JPH03217039A - Inspection of wire bonding and wire bonder - Google Patents

Abstract

PURPOSE:To perform an inspection, even if a wire bonder is in operation, without requiring to take out a lead frame from a magazine for inspection by constituting the title method so that the arbitrary picture of a bonded lead frame picked up through an image-pickup device can be stored in a picture memory and reproduced. CONSTITUTION:An apparatus is equipped with a carrier means 3 for carrying a lead frame 4 to a bonding stage, a bonding means 1 for positioning the carried lead frame 4 and displacing a wire-holding tool relatively to the lead frame 4 and semiconductor pellet to perform bonding, a magazine 2 for housing the bonded lead frame 4, an image pickup means 6 provided between the bonding means 1 and housing magazine 2 and a picture storing and reproducing means 9 having a picture memory capable of writing and reading an image-picked up picture, and an arbitrary picture of the bonded lead frame picked up by the image pickup device 6 according to a picture storage starting command is stored in the picture memory and the stored picture can be read from the picture memory and reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire bonding inspection method and a wire bonding apparatus in the assembly process of semiconductor integrated circuits (ICs) and the like.

[Background Art] When manufacturing semiconductor integrated circuits (ICs) and large-scale integrated circuits (LSIs), a lead frame on which semiconductor pellets are arranged is positioned by a conveying device, and then a tool for holding wires is moved to the lead frame. By displacing the wires relative to the semiconductor pellet, the wires are guided and bonded to the lead posts provided on the lead frame and the pads of the semiconductor pellet, respectively. Conventionally, inspections such as the loop shape of the wire connected to the lead post of the lead frame and the pad of the semiconductor pellet that have been bonded through such a process, and whether the wire is securely connected are carried out by sampling immediately after wire bonding. It is done by. In this inspection, the inspector stops the wire bonding equipment, carefully removes the lead frame stored in the magazine from the magazine, and uses a microscope to visually check the wire loop shape and whether the wires are bonded correctly. The method of inspection is being taken.

[Problems to be Solved by the Invention] However, in the conventional wire bonding inspection method, the inspector stops the wire bonding device to inspect the lead frame, takes the lead frame out of the magazine, inspects it, and then inspects it again. Since the lead frame is stored back in the magazine, there are drawbacks such as impact on the lead frame during transport or contact with other objects, which may destroy the wire shape. Furthermore, the conventional inspection method has the disadvantage that the wire bonding apparatus must be stopped for inspection, which reduces work efficiency.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and there is no need to take out the lead frame from the magazine for inspection, and even when the wire bonding machine is in operation, an inspector can inspect the bonded leads without having to take them out. It is an object of the present invention to provide a wire bonding inspection method and a wire bonding device capable of performing an inspection by projecting a frame image on a video device.

[Means for Solving the Problems] The present invention provides a conveying means for conveying a lead frame to a bonding stage, and a tool for positioning the lead frame conveyed by the conveying means and holding wires, for transporting the lead frame and semiconductor pellets. bonding means for guiding and bonding the wire to a lead post provided on the lead frame and a pad on the semiconductor pellet by displacing the wire relative to the lead frame; a magazine for storage, at least one or more imaging means provided between the bonding means and the storage magazine, and an image storage and reproduction means having an image memory capable of writing and reading images captured by the imaging means. storing an arbitrary image of the bonded lead frame imaged by the imaging device in response to an image storage start command to the image storage and reproducing means, and reading out and reproducing the stored image from the image memory. It is configured so that it can be done.

The present invention provides a means for transporting a lead frame to a bonding stage, and a tool for positioning the lead frame transported by the transport means and holding a wire, and for displacing the lead frame and the semiconductor pellet relative to the lead frame and the semiconductor pellet. a bonding means for guiding and bonding the wire to a lead post provided on the lead frame and a pad on the semiconductor pellet, respectively; an imaging means disposed close to the bonding means and movable; It is equipped with a magazine for storing rebonded lead frames, and an image storage and reproducing means having an image memory capable of writing and reading images captured by the image capturing means, and the image storing and reproducing means is provided with an image storage start command to the image storing and reproducing means. The bonding means is moved to a set position, the image of the bonded lead frame is stored in an image memory by the imaging device, and the stored image can be read out from the image memory and reproduced. It is.

The present invention transports a lead frame to a rebonding stage by a transport means, positions the transported lead frame, and displaces a tool for holding wires relative to the lead frame and the semiconductor pellet. Wires are guided and bonded to the lead post provided on the lead frame and the pad on the semiconductor pellet, respectively, and the number of the bonded lead frame and the position of the semiconductor pellet placed on the lead frame are set in advance. The control means determines whether the lead frame number and the position of the semiconductor pellet placed on the lead frame match, and if they match, the control means performs rebonding. The lead frame is imaged and the image can be stored and played back.

[Example] Next, an example of the present invention will be described in detail using the drawings.

FIG. 1 shows a wire bonding apparatus used in this embodiment.

In FIG. 1, the bonding head 1 is
It is mounted on an XY table (not shown) that can be moved in the X and Y directions, and is positioned between the lead post of the lead frame and the pad on the semiconductor pellet by moving relative q in the X and Y directions. This is a wire bonding connection. A lead frame 4 on which a plurality of semiconductor pellets are arranged is housed in a supply side magazine 5, and the lead frame 4 housed in this magazine 5 is delivered onto a transport device 3. This magazine 5 is configured to be intermittently movable up and down by a lifting means (not shown), and is configured so that lead frames 4 can be sequentially delivered onto the conveying device 3. Lead frame 4 sent out onto this conveyance device 3
is detected by a sensor (not shown) and is intermittently sent one frame at a time below the bonding arm of the bonding head 1 while being regulated in the width direction by a guide means (not shown).

When the lead frame 4 reaches the bonding stage where the bonding operation is performed, a sensor (not shown) detects the presence or absence of the lead frame 4, and the lead posts of the lead frame and the pads on the semiconductor pellet are relatively positioned, and the bonding 10 head is established. 1, a wire bonding connection is made. This bonding-connected lead frame 4 is 1
After being intermittently fed frame by frame and sequentially wire bonded, they are stored in the storage magazine 2. This storage magazine 2 is also configured to be intermittently movable up and down by a lifting means (not shown), and is configured to sequentially store lead frames 4 connected by bonding. This lead frame 4 usually has a plurality of semiconductor pellets arranged thereon. In the apparatus shown in FIG. 1, a TV camera 6 is installed between the bonding head 1 and the storage magazine 2 in addition to an imaging device (not shown), which is mounted on the bonding head 1 and is comprised of a TV camera or the like that performs image processing. , optical lens 7,
An imaging device including an illumination light 8 and the like is provided. Below the optical lens 7 of the image aligning device, a sensor (not shown) comprising a known optical sensor or the like for detecting the presence or absence of the lead frame 4 is provided in the conveying device 3. This TV
The camera 6 is configured so as to be able to process not only normal television signals but also binary signals. The video signal from the TV camera 6 is input to an image storage/reproduction device 9 having a built-in image memory. A block diagram showing the circuit configuration of this image storage/reproduction device 9 is shown in FIG.

In the figure, an image captured by an image manipulation device such as a TV camera 6 is converted from an analog signal to a digital signal by an A/D converter 12, and then stored in an image memory 14. Timing control of writing and reading images into and from the image memory 14 is performed by a control circuit 15. The image memory 14 is a memory that can be written to and read out at any time, and can store one frame. Since the image memory 14 is equipped with a plurality of frame memories, images of a plurality of frames (semiconductor chips) can be stored in this embodiment. This image storage/reproduction device 9 is equipped with a CPU 16 that issues various control commands, a floppy disk control 17, a communication control 18, a key control 19, and an input/output control 20. The floppy disk control 17 is a control circuit for recording the image stored in the image memory 14 onto an external magnetic storage medium such as a floppy disk, and the communication control 18 is a control circuit for recording the image stored in the image memory 14 on an external magnetic storage medium such as a floppy disk. This is a control circuit for transmitting images stored in the image storage/reproduction device 9 to the image processing device via a communication line.

Further, the key control 19 is an operation means for importing an image that the operator wants to store into the image memory 14 using the image storage/reproduction device 9, and the input/output control 2
Reference numeral 0 is connected to the wire bonding control device 11 shown in FIG. 1, and is used to output commands such as an image storage start command based on commands from the wire bonding control device 11 side. This wire bonding control device 11 is separately provided with key controls (not shown) for performing various operations of the wire bonding device, and the lead frame can be stored in advance in the image memory 14 in the image storage and reproducing device 9. You can set the required number of frames, etc. This stored image can be recorded on an external storage medium such as a floppy disk, and by connecting to a communication line, the stored image can be sent to an external image processing device via the communication line. It is configured so that it can be done.

Furthermore, when an inspector needs to inspect the wire bonding results, he or she performs the inspection by displaying the image of the bonded lead frame stored in the image storage and reproducing device 9 on the television monitor 10.

Next, the operation of this embodiment having the above configuration will be explained.

The lead frame 4 delivered from the supply side magazine 5 onto the conveying device 3 is bonded by the bonding head 1 and then intermittently fed one frame at a time. The lead frame 4 bonded by the bonding head 1 is located under an imaging device such as a TV camera 6.

For example, to store images of 5 lead frames,
The required number of frames is set in the wire bonding control device 11 in advance. The wire bonding control device 11 is
After conveying the lead frame, a storage start signal is sent to the image storage/reproduction device 14 9, and the signal from the imaging device is converted by the A/D converter 12 and stored in the image memory 14. As a result, after the lead post of the lead frame and the pad on the semiconductor pellet are connected by wire bonding, they are sent intermittently one after another, and the images for five frames preset in the image memory are automatically generated. is memorized.

In order for an inspector to inspect wire bonding on a wire bonding device, a playback switch (not shown) provided in the key control 19 of the image storage and playback device 9 is required.
Press to recall the image of the required frame from the image memory 14. At this time, the D/A converter 13 causes the image memory l4 to
The image stored in the digital signal is converted into an analog signal, and the image is instantly displayed on the television monitor 10. Since the same image is displayed on the television monitor 10 until the reproduction switch is pressed again, the same image can be viewed on the monitor until the inspector completes the necessary inspection. If this image does not need to be inspected immediately, it can be recorded on an external storage medium such as a floppy disk via the floppy disk 15 control 17, or it can be recorded on an external storage medium such as a floppy disk via the communication control 18 using a communication line. Images can be sent to a processing device and reproduced for inspection when necessary. By doing so, it is possible to erase the already written image and write a new image in the memory. In addition, by changing the field of view of the optical lens by changing the magnification of the optical lens depending on the inspection content, and by installing at least one or more multiple imaging devices, it is possible to obtain an overall image of the lead frame as shown in Figure 3. You can also store a portion of the image. By changing the field of view of the optical lens in this manner, it is possible to easily check whether the wire bonding connection is being made reliably. For example, if the entire image is captured and then a portion corresponding to the entire image is enlarged and displayed, the connection status of the wires can be immediately determined.

Next, a method of counting lead frame numbers and frame numbers using the apparatus having the configuration of the above embodiment will be described. A sensor (not shown) for detecting lead frames is provided near the supply side magazine 5 on the transport device 3, and a counter (not shown) for counting the number of lead frames detected by the sensor is provided. It is provided in the wire bonding control device 11. Furthermore, sensors for detecting the lead frame 4 are provided at the bonding stage position on the transport device 3 and below the optical lens 7 of the imaging device.

First, let A be the number of frames in the lead frame. Here the fifth
As shown in the figure, A=6.

Next, referring to the flowchart shown in FIG. 4, the magazine 5 containing the lead frame 4 is set on the supply side of the wire bonding apparatus shown in FIG. 1 (step S). When the first lead frame 4 sent from the magazine 5 onto the transport device 3 is detected by a sensor (not shown) provided in the transport device 3 (step S2), the wire bonding control device The counter 11 sets the number F of the lead frame 4 to 1, and sets the number K of the lead frames 4 to 0 (step S3). Next, after the lead frame 4 is conveyed one frame at a time on the conveying device 3 (step S4), it is determined whether the lead frame 4 is present on the bonding stage (step SS). If there is no lead frame 4 on this bonding stage, that is,
Even if there is a gap of one frame between lead frames, the already bonded lead frame 4 may be located at the imaging position. Therefore, in this case, it is necessary to count the number of frames on the lead frame 4, so in step S9, the number of frames on the lead frame 4 is counted.
It is determined whether or not is at the imaging position. If there is no lead frame 4 at this imaging position, step S4
Returning to step 2, the lead frame 4 is transported and the process moves to the next step.

Next, when the lead frame 4 is on the bonding stage, the position of the pellet is detected (step S6) 1 8 ? in the same way as in normal wire bonding. Then, wire bonding is performed (step S7), and it is determined in step S8 whether all wire bonding has been completed. If it has not ended, step S7 is continued; if it has ended, it is determined whether the lead frame 4 is at the imaging position (step S.)
. Here, if there is no lead frame 4, step S4
Returning to step Sho, the above steps are repeated, and if lead frame 4 is present, the process moves to step Sho and KK+1 is set. Here, since A=6, in step S1, if K>A, the next lead frame 4 is set at the imaging position, so F←F+1, K-1 is set (step S1 ■). However, in step S II, K
>A, it means that the new lead frame 4 has not been set at the imaging position, so step S1
Without performing the setting (2), the process moves to step Sl3 and it is determined whether or not the number and frame position of the lead frame 4 match. If they do not match, the process moves to step S4, the lead frame is transported, and 1 9 ? If so, a storage start signal to the image storage/reproduction device 9 is outputted from the wire bonding control device 11 (step S, 4).L image is stored (step S+6).L moves to the lead frame conveying process of step S4.

Also, when the setting in step S12 is made, the process moves to the steps 318 to 18 described above.

Since the number of the lead frame and the number of frames can be counted and stored as an image through the above process, the number M and the number of frames N of the lead frame 4 whose image is to be stored are set in advance by the wire bonding control device 11. Accordingly, the number M and the number N of frames of a predetermined lead frame 4 can be automatically stored using the apparatus shown in FIG.

Next, although the apparatus shown in FIG. 1 uses an imaging device consisting of a TV camera 6, an optical lens 7, and an illumination light 8, it is mounted on the bonding head 1 without using such a separate imaging device. An image of the lead frame 4 can be stored using an imaging device having the same functions as the imaging device including the TV camera 206, optical lens 7, and the like. This will be explained using the flowchart shown in FIG. Note that the other configurations are the same as those shown in FIG.

First, the number M and frame position N of the lead frame whose image is to be stored are set in the wire bonding control device 1l in advance. This setting can be made multiple times. Next, the wire bonding control device 11 determines the position of the image to be stored on the XY stage on which the bonding head 1 is mounted.
to be memorized. This is because the bonded state is imaged after the XY stage moves and the bonding work is performed, so the position to be imaged needs to be stored as a position on the coordinates of the XY stage.

As shown in FIG. 6, when a start command is issued from the wire bonding control device 11, the position of the pellet is detected in step SA. Step SA. Wire bonding is performed in step 21 SA. It is determined whether wire bonding has been completed. If this wire bonding has not been completed, the process returns to the previous step, and if the bonding has been completed, it is determined in step SA4 whether or not the preset lead frame number M and the position of the frame N match. Ru. If they do not match, step SA
．． , and transport the lead frame. Here, the number F of lead frames 4 is counted by a counter, and the number K of frames of lead frames 4 is also counted, so this F. It will be determined whether =M and K=N. In this step SA4, lead frame 4
If the numbers and the number of frames match, the XY stage is moved to the image storage position. This image storage location is XY
Since it is stored as a coordinate point of the table, after this movement is performed, an image storage start command signal is issued to the image storage/reproduction device 9 (SA6). Store image (SA.).

After the storage of this image is completed, the lead frame is transported (SA). After this conveyance is completed, step SA. The process returns to , and the same steps as above are repeated.

As described above, since the image of the number and frame position of the lead frame 4 preset by the command from the wire bonding control device 11 has been taken into the image memory 14 of the image storage and reproducing device 9, the connection status of wire bonding can be checked. When the inspector is about to inspect, press key control 19.
By operating the playback switch provided on the operating means of the TV monitor 1, a desired image is recalled from the memory.
It can be projected on 0. By viewing and inspecting this projected image, it is possible to determine whether the wire bonding is good or bad.

In this embodiment, the image storage/reproduction device 9 and the wire bonding control device 11 are configured separately, but they may be configured integrally.

[Effects of the Invention] As explained above, according to the present invention, there is no need for an inspector to stop the wire bonding machine to inspect the lead frame, and bonding can be performed even when the wire bonding machine is in operation. Since the image of the finished lead frame can be displayed on an imaging device for inspection, there is an advantage that the wire shape will not be damaged due to impact on the lead frame or contact with other objects. Further, according to the present invention, there is no need to stop the wire bonding apparatus for inspection, which has the effect of improving work efficiency. Moreover, since a plurality of images can be stored, the connection status of wire bonding can be displayed on video for comparative inspection, etc., and quality control can also be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention, and shows a wire bonding device used in the present invention, FIG. 2 is a block diagram of the image storage and reproducing device shown in FIG. 1, and FIG. FIG. 4 is a flowchart illustrating a method of counting lead frame numbers and frame numbers and storing images according to the present invention, and FIG. is a schematic diagram of a lead frame used in the present invention,
FIG. 6 is a flowchart showing a method for automatically detecting lead frame numbers and frame positions and storing them in an image memory using the wire bonding control device according to the present invention. 1... Bonding head, 2... Storage magazine,
3... Conveyance device, 4... Lead frame, 5... Supply side magazine, 6... TV camera, 7... Optical lens, 8... Lighting lamp, 9... Image storage and playback device , 10
... Te1/Bi monitor, l1... Wire bonding control device, 12... A/D converter, l3... D/A
Converter, l4... Image memory, 15... Control circuit.
16...CPU. 17...Floppy disk control, 18...Communication control 0-Jlz, 19...
-Key control, 20...Input/output control.

Claims (5)

[Claims] (1) By displacing a conveying means for conveying the lead frame to the bonding stage and a tool for positioning the lead frame conveyed by the conveying means and holding the wires relative to the lead frame and the semiconductor pellet. A bonding means for guiding and bonding the wire to a lead post provided on the lead frame and a pad on the semiconductor pellet, a magazine for storing the lead frame bonded by the bonding means, and the bonding means. and at least one imaging means provided between the storage magazine and the storage magazine, and an image storage and reproducing means having an image memory capable of writing and reading images captured by the imaging means, and the image storage and reproducing means includes: An arbitrary image of the bonded lead frame captured by the imaging device according to the image storage start command is stored in the image memory, and the stored image can be read out from the image memory and reproduced. wire bonding equipment. (2) By displacing a conveying means for conveying the lead frame to the bonding stage and a tool for positioning the lead frame conveyed by the conveying means and holding the wires relative to the lead frame and the semiconductor pellet. bonding means for guiding and bonding the wire to a lead post provided on the lead frame and a pad on the semiconductor pellet, respectively; an imaging means disposed close to the bonding means and movable; and an image storage/reproduction means having an image memory capable of writing/reading images captured by the image pickup means, the image storage/reproduction means being set in advance by an image storage start command to the image storage/reproduction means. Wire bonding characterized in that the bonding means is moved to a position, the image of the bonded lead frame is stored in an image memory by the imaging device, and the stored image can be read out from the image memory and reproduced. Device. (3) The wire bonding apparatus according to claim 1 or 2, wherein the image stored in the image memory can be read out and written to another storage medium. (4) The wire according to claim 1 or claim 2, characterized in that the image stored in the image memory can be read and reproduced by another image storage and reproduction device via communication means. bonding equipment. (5) The lead frame is transported to the bonding stage by the transport means, and the tool for positioning the transported lead frame and holding the wire is displaced relative to the lead frame and the semiconductor pellet, and the wire is moved to the bonding stage. Bonding is performed by guiding the lead post provided on the lead frame and the pad on the semiconductor pellet, respectively, and the number of the bonded lead frame and the position of the semiconductor pellet disposed on the lead frame are set in advance. The control means determines whether the number of the lead frame matches the position of the semiconductor pellet arranged on the lead frame, and if the number matches the position of the semiconductor pellet arranged on the lead frame, the control means controls the bonded lead frame. A wire bonding inspection method characterized by capturing an image, storing the image, and reproducing the image.