JP6110167B2 - Die recognition means, die recognition method and die bonder - Google Patents

Description

  The present invention relates to a die bonder, and more particularly to a die recognition means and a die recognition method.

In the conventional die bonder, when a die is picked up from a wafer and placed on an intermediate stage, it is inspected for any defects such as misalignment and chipping.
Also, inspection is performed after die bonding to a frame or a substrate (hereinafter collectively referred to as a substrate). It should be noted that the inspection after die bonding can be inspected with a die bonder or with another inspection device.

However, in the conventional inspection, an image is picked up by one camera from above or obliquely from the die, and the picked-up image is inspected by visual observation or image processing.
In an image picked up from one direction, there may be a case where there is a defective portion such as a position shift or a defect that causes an inspection failure in a non-imaged portion on the opposite side.
In order to correct the position of the die, it is easiest to calculate the position by taking an image with the camera from directly above the die. However, it is physically difficult because the tip of the nozzle that picks up or sucks the die is placed directly above the die. In addition, in order to obtain data for correcting the position of the die, it is conceivable to move the nozzle and move the camera directly above to take an image, but this increases the offset (moving) operation, which increases the bonding time. was there.
For this reason, the die recognition camera is installed diagonally upward, and there are many methods for imaging the die from diagonally upward.

  In the technique described in Patent Document 1, the die picked up by the bonding head is picked up from below by the component recognition camera while the die is picked up from the wafer and placed on the intermediate stage. In this case, only the positional deviation was known, the side surface of the die was not imaged, and the side surface abnormality could not be detected.

JP 2012-248778 A

As described above, in the conventional technique, inspection is performed with an image captured in one direction from an oblique direction, and therefore, information for inspection cannot be obtained sufficiently, and there is a factor that causes the inspection to be rejected in a portion that is not captured. There was a case that I didn't know.
In view of the above-described problems, an object of the present invention is to provide a die recognition unit, a die recognition method, and a die bonder that can obtain a large amount of information with one camera.

  In order to achieve the above object, the die recognition means of the present invention includes a wafer supply unit for holding a wafer, a pickup device that picks up a die from the wafer and places it on a delivery stage, and a die from the delivery stage to the die. A die recognizing means of a die bonder comprising a bonding head part for picking up and bonding to a substrate, and a control part, wherein the dies placed on the delivery stage are located at at least two locations, such as diagonally upward left and diagonally upward right At least two first mirrors that reflect a subject image that is incident from at least two different directions and that respectively reflects downward in the vertical direction of the delivery stage, and is installed directly below the first mirror at the lower part of the delivery stage. At least two second mirrors that respectively reflect the subject image reflected from the first mirror in the horizontal direction. , At least two third mirrors that are installed immediately below the center of the delivery stage and that reflect the subject image reflected from the second mirror downward in the vertical direction, and the third mirror A first feature is that it has a single camera that is installed immediately below and captures the subject image reflected from the third mirror.

  In the die recognition means according to the first feature of the present invention, the control unit performs coordinate transformation of two subject images captured by the camera to synthesize a three-dimensional image as a second feature of the present invention. To do.

  In order to achieve the above object, a die recognition method of the present invention includes a wafer supply step for holding a wafer, a pickup step for picking up a die from the wafer and placing it on a delivery stage, and a die from the delivery stage. A die recognition method of a die bonder comprising a bonding step of picking up and bonding to a substrate, wherein the die placed on the delivery stage is imaged from at least two different directions such as an upper left direction and an upper right direction The third feature.

  In the die recognition method according to the third feature of the present invention, a fourth feature of the present invention is that a three-dimensional image is acquired by combining the plurality of captured subject images.

  In order to achieve the above object, a die bonder of the present invention includes a wafer supply unit that holds a wafer, a pickup device that picks up a die from the wafer and places it on a delivery stage, and picks up the die from the delivery stage A die bonder having a bonding head unit for bonding to a substrate and a control unit, wherein the dies placed on the delivery stage are installed in at least two locations, such as diagonally upward left and diagonally upward right, and at least two different directions And at least two first mirrors that respectively reflect the subject image incident on the transfer stage vertically downward from the delivery stage, and are reflected directly from the first mirror below the first mirror and below the delivery stage. At least two second mirrors that respectively reflect the subject image in the horizontal direction, and the delivery step And at least two third mirrors which are installed immediately below the center of the lens and reflect the subject image reflected from the second mirror downward in the vertical direction, respectively, and immediately below the third mirror. And a single camera that captures the subject image reflected from the third mirror, and the control unit synthesizes a three-dimensional image of the die from a plurality of images captured by the camera. According to a fifth feature of the present invention, the position of a die bonded to the substrate is corrected based on the obtained image.

  In the die bonder according to the fifth aspect of the present invention, the control unit calculates a die shift amount based on the synthesized image, and determines a suction position of the suction nozzle of the bonding head unit from the calculated shift amount. The sixth feature of the present invention is that the die is adsorbed by correction.

  In order to achieve the above object, a die recognition means, a die recognition method and a die bonder of the present invention include:

  According to the present invention, it is possible to realize a die recognition means, a die recognition method, and a die bonder that can obtain a lot of inspection information with a single camera.

It is the conceptual diagram which looked at the die bonder which is one Embodiment of this invention from the top. It is a figure which shows the external appearance perspective view of the pick-up apparatus which is one Embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the pick-up apparatus which is one Embodiment of this invention. It is a schematic side view of the principal part of one Example of the die bonder of this invention. It is a block diagram which shows the structure of one Example of the imaging unit for die position confirmation in the die bonder of this invention. It is a figure which shows one Example of the display screen of the image imaged by the imaging unit for die position confirmation in the die bonder of this invention. For the left and right images 4L and 4R acquired in FIG. 5, the three-dimensional image 4D of the die 4 is synthesized by known coordinate transformation such as affine transformation, and the synthesized three-dimensional image 4D is displayed on the screen 9.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In addition, the following description is for describing one embodiment of the present invention, and does not limit the scope of the present invention. Accordingly, those skilled in the art can employ embodiments in which these elements or all of the elements are replaced with equivalent ones, and these embodiments are also included in the scope of the present invention.
In the description of each drawing, the same reference numerals are assigned to components having the same function, and the description is omitted as much as possible to avoid duplication.

An embodiment of a die bonder of the present invention will be described with reference to FIG. FIG. 1 is a conceptual view of an embodiment of a die bonder according to the present invention as viewed from above. Reference numeral 100 denotes a die bonder, 1 denotes a wafer supply unit, 2 denotes a workpiece supply / conveyance unit, 3 denotes a die bonding unit, and 10 denotes a control unit that controls the operation of the die bonder.
The die bonder roughly includes a wafer supply unit 1, a work supply / conveyance unit 2, and a die bonding unit 3.
In the workpiece supply / conveyance unit 2, 21 is a stack loader, 22 is a frame feeder, and 23 is an unloader. Furthermore, in the die bonding part 3, 31 is a board | substrate check part, 32 is a bonding head part. Furthermore, in the wafer supply unit 1, 11 is a wafer cassette lifter, and 12 is a pickup device.
Reference numeral 10 denotes a control unit that accesses each device of the die bonder 100 and controls each device according to a predetermined program. In FIG. 1, signal lines for mutual access to each device are omitted.

The workpiece supply / conveyance unit 2 is responsible for the substrate conveyance process during the die bonding process. In the workpiece supply / conveyance unit 2, the substrate P (not shown) is supplied to the frame feeder 22 by the stack loader 21. The substrate P supplied to the frame feeder 22 is transferred to the unloader 23 through two processing positions on the frame feeder 22.
The die bonding unit 3 is responsible for the die attach process during the die bonding process. In the die bonding unit 3, the substrate check unit 31 images the substrate P transported by the frame feeder 22 with the imaging device C <b> 2 (not shown) and transmits the captured image data to the control unit 10. The control unit 10 calculates the amount of deviation between the origin of the die bonder 100 and the reference point on the transported substrate P by image processing. A correction amount at the time of bonding is calculated from the calculated shift amount.

The bonding head unit 32 picks up the die 4 (see FIG. 2 or FIG. 3) from the delivery stage 444 (see FIG. 4) of the pickup device 12 and moves the picked up die 4 upward and parallel to the frame feeder 22. Move to the bonding point. The bonding head unit 32 lowers the die 4 and bonds it onto the substrate P. At this time, the control unit 10 corrects and bonds the position to which the die 4 is attached using the correction amount based on the image captured by the substrate check unit 31.
Further, the wafer supply unit 1 performs a peeling process during the die bonding process. In the wafer supply unit 1, the wafer cassette lifter 11 has a wafer cassette (not shown) in which wafer rings are stored, and sequentially supplies the wafer rings to the pickup device 12. Detailed configuration and operation of the pickup device 12 will be described with reference to FIGS.

  The configuration of the pickup device 12 will be described with reference to FIGS. FIG. 2 is an external perspective view of the pickup device 12. FIG. 3 is a schematic cross-sectional view showing the main part of the pickup device 12. In the pickup apparatus 12, 5 is a wafer, 4 is an individual die of the wafer 5, 14 is a wafer ring, 15 is an expanding ring, 16 is a dicing tape, 17 is a support ring, 18 is a die attach film (die bonding tape), Reference numeral 50 denotes a push-up unit.

As shown in FIGS. 2 and 3, a die attach film 18 is attached to the rear surface (lower surface) of the wafer 5, and a dicing tape 16 is further attached to the rear surface (lower surface). Further, the edge of the dicing tape 16 is sandwiched and fixed between the wafer ring 14 and the expand ring 15.
That is, the pickup device 12 includes an expand ring 15 that holds the wafer ring 14, a support ring 17 that horizontally positions a dicing tape 16 that is held by the wafer ring 14 and to which a plurality of dies 4 (wafers 5) are bonded, and a support ring 17. A push-up unit 50 is disposed inside the ring 17 and pushes the die 4 upward.
The push-up unit 50 is moved in the vertical direction by a drive mechanism (not shown). The movement for positioning the push-up unit 50 to the die 4 to be picked up is, for example, such that the wafer ring 14 moves in the horizontal (X) direction and the push-up unit 50 moves in the depth (Y) direction. However, it is obvious that either of them may move relatively. The movement for aligning the suction nozzle 6 (see FIG. 4) and the die 4 to be picked up is the same.

  In recent years, the adhesive for die bonding is changed from a liquid form to a film form, and has a structure in which a film-like adhesive material called a die attach film 18 is pasted between the wafer 5 and the dicing tape 16. In the wafer 5 having the die attach film 18 on the back surface, dicing is performed on the wafer 5 and the die attach film 18. Recently, there is a tape in which the dicing tape 16 and the die attach film 18 are integrated. In this case as well, dicing is performed on the wafer 5 and the die attach film 18.

The pickup device 12 lowers the expanding ring 15 holding the wafer ring 14 when pushing up the die 4. At this time, since the support ring 17 does not descend, the dicing tape 16 held on the wafer ring 14 is stretched to widen the distance between the dies 4 so that the respective dies 4 can be easily recognized and the dies to be picked up are separated. It becomes easy to raise.
The push-up unit 50 pushes up the die 4 from below and improves the pick-up property of the die 4 by the suction nozzle 6. In the wafer 5 having the die attach film 18, dicing is performed on the wafer 5 and the die attach film 18. Therefore, in the peeling (pushing up) step, the die 4 and the die attach film 18 are peeled off from the dicing tape 16, and the suction nozzle 6 sucks and picks up the die 4.

FIG. 4 is a schematic side view of the main part of an embodiment of the die bonder of the present invention. The die bonder in FIG. 4 is an example in which a delivery stage is used to correct the die suction position and accurately perform die attach. Reference numeral 100 denotes a die bonder main body, 12 denotes a pickup device, 444 denotes a delivery stage, 3 denotes a die bonding unit for performing a die attach operation, 4 denotes a die, and 6 denotes a suction nozzle that sucks the die 4 and attaches it to the substrate P. Also, 5 is a wafer, 14 is a wafer ring for holding the wafer 5, 450 is a push-up unit for pushing up the die 4 from below and peeling the die from the dicing tape, and 46 is a vacuum suction of the die 4 placed on the delivery stage 444 A vacuum chamber P is a substrate which is a mounting member on which the die 4 is mounted, and 13 is an attachment table of the die bonding unit 3. Reference numeral 45 denotes a resin coating portion on the upper surface of the delivery stage 444, 62 denotes an upper surface of the attachment table 13, 130 denotes an opening on the upper surface of the attachment table 13, and 140 denotes a heating device for heating the attachment table 13.
FIG. 4 does not show the die recognition camera. The die recognition camera of the present invention will be described with reference to FIG.

In FIG. 4, the wafer ring 14 of the pickup device 12 holds a semiconductor wafer 5 (referred to herein as a wafer) 5 in which a large number of dies 4 are assembled. The wafer 5 is diced so that it can be picked up separately for each die 4. The push-up unit 450 pushes up the die 4 to be picked up on the wafer 5 from below, and peels off the die 4 from the dicing tape attached to the back surface of the wafer 5. On the other hand, the suction nozzle 6 descends to a position directly above the die 4 to be picked up, and vacuum-sucks the die 4 peeled from the dicing tape. The suction nozzle 6 places the die 4 on a predetermined position of the delivery stage 444 by performing a lifting operation, a parallel movement operation, and a lowering operation after vacuum suction of the die 4.
The die 4 placed on the delivery stage 444 is captured by the imaging unit C1 (see FIG. 5) for confirming the die position, and the captured image is transmitted to the control unit of the die bonder. The control unit 10 calculates the deviation amount (X, Y, θ direction) of the die 4 on the delivery stage 444 from the die position reference point of the die bonder by image processing. The die position reference point holds a predetermined position of the delivery stage 444 as an initial setting of the apparatus in advance.
The control unit 10 adsorbs the die 4 by correcting the adsorption position of the adsorption nozzle 6 from the calculated shift amount of the die 4. The suction nozzle 6 that sucks the die 4 from the delivery stage 444 lifts, translates, and descends after the vacuum suction of the die 4 and moves the die 4 to a predetermined position on the substrate P on the die attach table 13 of the die bonding unit 3. Attach 4

  Further, similarly to the imaging unit C1 for confirming the die position, the substrate P placed on the attach table 13 is also imaged by the imaging device C2 for confirming the substrate position (not shown), and the captured image is controlled by the die bonder. Sent to the department. The control unit 10 calculates the amount of deviation (X, Y, θ direction) of the substrate P from the substrate position reference point of the die bonder by image processing. The substrate position reference point holds a predetermined position of the substrate check unit as an initial setting of the apparatus in advance.

Next, the imaging unit C1 for confirming the die position according to the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of an embodiment of the imaging unit C1 for confirming the die position in the die bonder of the present invention.
FIG. 5 is a sectional view showing the vicinity of the delivery stage 444 (inside the broken line frame 500) in the schematic side view of the main part of the embodiment of the die bonder of the present invention shown in FIG.
In FIG. 5, the die 4 sucked by the suction nozzle 6 and picked up from the wafer 5 is placed on the resin coating portion 45 of the delivery stage 444. At this time, the vacuum chamber 46 of the delivery stage 444 is decompressed by a vacuum pump (not shown), and the die 4 is sucked by a plurality of suction holes (not shown) provided in the resin coating portion 45 and separated from the suction nozzle 6.

The die recognition camera 42 is installed directly below the delivery stage 444 and is installed with the viewing angle vertically upward so that the center axis of the delivery stage 444 coincides with the optical axis of the die recognition camera 42.
The die 4 placed on the delivery stage 444 is appropriately irradiated with illumination (not shown) in order to obtain a brightness that can be imaged by the die recognition camera 42. The reflected light of the irradiated light (subject images 4L and 4R (broken arrows) on the die 4) enters the left and right mirrors 7L1 and 7R1. Preferably, the reflected lights 4L and 4R form a viewing angle and an optical axis so as to be imaged obliquely from above. With this configuration, the die recognition camera 42 can take an image from the lower side of the die 4 to the surface.
The optical image incident on the mirror 7L1 is reflected and vertically incident on the mirror 7L2 installed below the delivery stage 444 in the vertical downward direction of the mirror 7L1. The light image incident on the mirror 7L2 is reflected (for example, reflected by 90 [°]) and incident in the horizontal direction on the mirror 7L3 installed at the same height as the mirror 7L2 just below the center of the delivery stage 444. To do. The light image incident on the mirror 7L3 is reflected (for example, 90 [°] reflection) and vertically incident along the optical axis of the die recognition camera 42 installed immediately below the mirror 7L3.
Similarly, the light image incident on the mirror 7R1 is reflected and vertically incident on the mirror 7R2 installed below the delivery stage 444 in the vertical downward direction of the mirror 7R1. The light image incident on the mirror 7R2 is reflected (for example, 90 [°] reflection) and is incident on the mirror 7R3 installed at the same height as the mirror 7R2 just below the center of the delivery stage 444 in the horizontal direction. To do. The light image incident on the mirror 7R3 is reflected (for example, 90 [°] reflection) and vertically incident along the optical axis of the die recognition camera 42 installed immediately below the mirror 7R3.
The die recognition camera 42 captures subject images reflected from the mirror 7L3 and the mirror 7R3, respectively.
Here, the imaging unit C1 includes a die recognition camera 42, mirrors 7L1, 7L2, and 7L3, mirrors 7R1, 7R2, and 7R3, and illumination (not shown). In addition, an image captured by the die recognition camera 42 of the image capturing unit C1 is output to the control unit 10, subjected to image processing, and also displayed on a display screen (not shown).

In FIG. 5, a mirror is installed so that the die 4 placed on the delivery stage 444 is imaged from the upper left and the upper right. However, it is not necessary to limit to the left-right direction, and you may install in arbitrary positions. This is more convenient for clearing restrictions on the device configuration such as a die bonder.
Also, the number of images may be two or more.
Furthermore, the installation position of the die recognition camera does not have to be directly below the delivery stage, and the optical axis direction of the camera may be set to be horizontal or oblique in consideration of the number of reflection mirrors, the installation location, and the like.

As a result, the die recognition camera 42 can capture an image of the die 4 placed on the delivery stage 444 as viewed from the left-right direction. It is a figure which shows one Example of the display screen of the image imaged by the imaging unit for die position confirmation in the die bonder of this invention.
For example, as shown in the screen 8 of FIG. 6A, an image of the die 4 viewed from the left direction is obtained on the left side of the screen 8, and an image of the die 4 viewed from the right direction is obtained on the right side of the screen 8.
Further, as shown in the screen 8 ′ of FIG. 6B, if the distant sides of the die imaged from the left and right are displayed at the center of the screen so as to be combined, it is easier to grasp the entire die 4.

7, the left and right images 4L and 4R acquired in FIG. 5 are synthesized by a known coordinate transformation such as affine transformation, and the three-dimensional image 4D of the die 4 is synthesized, and the synthesized three-dimensional image 4D is displayed on the screen 9. Is.
Note that the three-dimensional image 4D can be arbitrarily rotated and displayed, and a plan view seen from the upper surface, a plan view seen from the lower surface, and side views seen from various directions, not limited to right and left, can be displayed. As a result, the worker can easily find a defective portion such as a position shift or a defect that results in an inspection failure.

According to the above-described embodiment, it is possible to realize a die recognition unit, a die recognition method, and a die bonder that can obtain a lot of inspection information with a single camera.
In addition, even with a video imaged obliquely from above with a single camera, a die recognition means, a die recognition method, and a die bonder that can be correctly aligned can be realized in the same manner as an image captured from directly above a die.

  1: Wafer supply unit, 2: Workpiece supply / conveyance unit, 3: Die bonding unit, 4: Die, 4R, 4L, 4D: Subject image, 5: Wafer, 6: Suction nozzle, 7L1-7L3, 7R1-7R3: Mirror, 8, 8 ′, 9: Screen, 8L: Image viewed from the left direction, 8R: Image viewed from the right direction, 8D: Three-dimensional image, 10: Control unit, 11: Wafer cassette lifter, 12: Pickup device 13: Attach table, 14: Wafer ring, 15: Expanding ring, 16: Dicing tape, 17: Support ring, 18: Die attach film, 21: Stack loader, 22: Frame feeder, 23: Unloader, 31: Substrate check Part 32: Bonding head part 42: Die recognition camera 45: Resin coating part 4 6: vacuum chamber, 50: push-up unit, 62: upper surface, 100: die bonder, 130: opening, 140: heating device, 444: delivery stage, 450: push-up unit, C1: imaging unit, P: substrate.

Claims (6)

A wafer supply unit that holds a wafer, a pickup device that picks up a die from the wafer and places it on a delivery stage, a bonding head unit that picks up the die from the delivery stage and bonds it to a substrate, and a control unit The die recognition means of the die bonder,
At least two dies that are placed on at least two locations, such as diagonally upward left and diagonally upward to the right, are placed on the delivery stage and reflect object images incident from at least two different directions downward in the vertical direction of the delivery stage. A first mirror and at least two second mirrors that are installed directly below the first mirror at the lower part of the delivery stage and respectively reflect the subject image reflected from the first mirror in the horizontal direction; At least two third mirrors that are installed immediately below the center of the delivery stage and reflect the subject image reflected from the second mirror downward in the vertical direction, respectively, and directly below the third mirror And a single camera for picking up subject images respectively reflected from the third mirror.   2. The die recognition means according to claim 1, wherein the control unit performs coordinate transformation of two subject images captured by the camera to synthesize a three-dimensional image. Die recognition of a die bonder comprising a wafer supply process for holding a wafer, a pickup process for picking up a die from the wafer and placing it on a delivery stage, and a bonding process for picking up the die from the delivery stage and bonding it to a substrate A method,
The die placed on the delivery stage is imaged from at least two different directions such as diagonally upward left and diagonally upward right ;
In the imaging, at least two first mirrors that reflect a subject image incident from at least two directions downward in the vertical direction of the delivery stage, respectively, and a lower part of the delivery stage, directly below the first mirror And at least two second mirrors that respectively reflect the subject image reflected from the first mirror in the horizontal direction and the second mirror that is installed immediately below the center of the delivery stage and reflected from the second mirror. By at least two third mirrors that respectively reflect the subject image vertically downward, and one camera that is installed directly below the third mirror and that captures the subject image reflected from the third mirror. die recognition method, which comprises carrying out.   4. The die recognition method according to claim 3, wherein a three-dimensional image is obtained by combining the plurality of captured subject images. A wafer supply unit that holds a wafer, a pickup device that picks up a die from the wafer and places it on a delivery stage, a bonding head unit that picks up the die from the delivery stage and bonds it to a substrate, and a control unit Die bonder,
At least two dies that are placed on at least two locations, such as diagonally upward left and diagonally upward to the right, are placed on the delivery stage and reflect object images incident from at least two different directions downward in the vertical direction of the delivery stage. A first mirror and at least two second mirrors that are installed directly below the first mirror at the lower part of the delivery stage and respectively reflect the subject image reflected from the first mirror in the horizontal direction; At least two third mirrors that are installed immediately below the center of the delivery stage and reflect the subject image reflected from the second mirror downward in the vertical direction, respectively, and directly below the third mirror And a single camera that captures the subject images reflected from the third mirror,
The said control part synthesize | combines the three-dimensional image of die | dye from the several image imaged with the said camera, and performs die position correction | amendment of die-bonding to the said board | substrate by the synthesize | combined image.   6. The die bonder according to claim 5, wherein the control unit calculates a shift amount of the die based on the synthesized image, and corrects a suction position of the suction nozzle of the bonding head unit from the calculated shift amount. A die bonder characterized by adsorbing water.

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