JP3686064B2 - Bonding method and bonding apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the assembly process of a semiconductor device, the present invention bonds a pad (electrode) on a chip to be bonded to an external lead formed on a lead frame or the like to be bonded to which the chip is attached. The present invention relates to a bonding method and a bonding apparatus for connecting with a wire or the like.
[0002]
[Prior art]
Conventionally, a part to be bonded having a chip composed of a plurality of LEDs, transistors, etc. on a lead frame or a substrate first detects the amount of deviation of one chip in the bonding area, and then uses the amount of deviation data. The position of the pad on the chip is corrected, and bonding between the chip pad and the lead on the lead frame is performed. Thereafter, the shift amount detection and bonding are sequentially repeated for a predetermined number of chips.
[0003]
In addition, first, a deviation amount of all the chips in the bonding area is detected, and after the deviation amount is detected, the pad and the lead may be bonded together.
[0004]
However, since the detection of the chip displacement amount in the bonding process and the bonding between the pad and the lead are performed sequentially, the proportion of the detection time of the displacement amount in the bonding step is large, so the productivity of the parts to be bonded is low. It was.
[0005]
For this reason, a bonding method is disclosed in which the detected device is wire-bonded based on the corrected data simultaneously with the detection of the shift amount (see, for example, Patent Document 1).
[0006]
The bonding method disclosed in Patent Document 1 will be described below with reference to FIG. The detector (camera) is attached to the bonding head at a pitch of two devices from the tool (capillary). An image of one or two points of any reference on the pellet (chip) of the first tenth device is detected and stored by a detector (camera), and then the actual detection point with respect to the reference point based on the stored image The amount of deviation is calculated by the computer, and the bonding points stored in advance in the computer are corrected and stored. When the detection is completed, the X motor is driven by one device, the detector is positioned above the ninth pellet, and the bonding point of the ninth device is similarly detected, corrected, and stored. Next, when the X motor is driven by one device and the detector is positioned above the eighth pellet, the tool is positioned above the tenth pellet and bonding of the tenth pellet previously detected and stored is performed. The motor is driven according to the detection signal of the point and lead bonding point, and the bonding head moves, the tool is guided to the bonding point, and the wire is connected to the bonding point of the tenth pellet and the bonding point of the lead for bonding. Do. While the bonding head is stopped during the bonding, the bonding point of the eighth device is detected and corrected in the same manner as described above and stored in the computer. Thereafter, the above operations are sequentially repeated to perform detection and wire bonding.
[0007]
As shown in FIG. 7, in steps 1 and 2, only the devices 10 and 9 are detected. In steps 3 to 10, the detection is performed for the devices 8 to 1 and the bonding is performed for the devices 10 to 3 at the same time. In steps 11 and 12, bonding is performed for the second and first devices.
[0008]
Thereby, since bonding and position detection are simultaneously performed by a plurality of devices, the detection time of the shift amount is shortened.
[0009]
[Patent Document 1]
JP 58-220435 A (page 6, FIG. 4)
[0010]
[Problems to be solved by the invention]
In the conventional bonding method, when wire bonding is performed, it is performed according to the bonding position coordinates of the pads and leads set in advance by self-teach or the like. The detection of the chip shift amount is a sequence for detecting the nth chip after the chip to be bonded. The detected chip displacement data corresponds to the chip n chips ahead of the currently bonded chip. Further, the detection order of chip deviation detection and the order of bonding chips are the same.
[0011]
FIG. 8A shows a configuration of a part to be bonded including the chips 20 attached to the substrate 30 in a matrix. When the distance between the capillary and the camera is set at an interval of one chip in the X direction (the camera is positioned on the chip number c5 when the capillary is positioned on the chip number c1 in FIG. 8A) In addition, in the bonding of the parts to be bonded shown in FIG. 8A, the chip detection order and the chip bonding order are the same as shown in FIG. 8B, so the camera mounted on the XY table, the bonding The capillary as a tool is moved from the chip number c4 to the chip number c5, and from the chip number c8 to the chip number c9, as shown by the dotted line in FIG. It is necessary to perform each movement of the chip number c12 to the chip number c13. As a result, the movement operation of the XY table increases, so that the movement time becomes longer, and the time required for the bonding process increases, resulting in a decrease in the number of bonded parts to be produced.
[0012]
Therefore, an object of the present invention is to provide a bonding method and a bonding apparatus that can improve the number of parts to be bonded by determining an optimal detection order based on the bonding order.
[0013]
[Means for Solving the Problems]
The bonding method according to the present invention includes a bonding unit that bonds to a component to be bonded, a positioning unit that moves the bonding unit relative to the component to be bonded two-dimensionally, and a positioning unit. An image pickup means for picking up an image of the mounted component to be bonded, a detection means for detecting a fixed point deviation amount of the bond target component from image data from an image pickup signal of the image pickup means, and a control means including a microprocessor. A bonding method for simultaneously detecting a chip shift amount and bonding in a bonding apparatus, wherein the control means determines whether the bonding means is based on a preset position of a bonding position and an offset amount between the bonding means and the imaging means. At the bonding position Calculating a chip as an object to be bonded part can be imaged by the imaging means when, and determining a detection order of the chips corresponding to the sequence of bonding operation, the chip which corresponds to the order of bonding operations A step of automatically creating and storing a pre-detection table storing the detection order, and during the bonding operation, the corresponding chip stored in the pre-detection table is imaged by the imaging unit, The amount of deviation of the chip is detected by the detecting means from the image data of the imaging means.
[0014]
The bonding apparatus according to the present invention includes a bonding unit that performs bonding on a component to be bonded, a positioning unit that moves the bonding unit relative to the component to be bonded two-dimensionally, and a positioning unit. An image pickup means for picking up an image of the mounted part to be bonded, a detection means for detecting a fixed point shift amount of the part to be bonded from image data from an image pickup signal of the image pickup means, and a control means including a microprocessor. A bonding apparatus for simultaneously detecting a chip shift amount and bonding, wherein the control means determines whether the bonding means is a bonding position based on the coordinates of the bonding position set in advance and the offset amount between the bonding means and the imaging means. Said imaging hand when located in Means for calculating a chip as imageable the bonding parts in, means for determining a detection order of the chips corresponding to the sequence of bonding operation, before storing the detection order of the chips corresponding to the sequence of bonding operations Means for automatically creating and storing a detection table, and during the bonding operation, the corresponding chip stored in the previous detection table is imaged by the imaging means, and the image data of the imaging means is used to The amount of deviation of the chip is detected by the detecting means.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a bonding method and a bonding apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a bonding apparatus according to the present invention, FIG. 2 is a flowchart for creating a pre-detection table for determining the order of chip displacement detection, and FIG. 3 is a matrix on a substrate as a part to be bonded. FIG. 4 is a diagram showing a pre-detection table of chips formed in a matrix shown in FIG. 3.
[0018]
As shown in FIG. 1, a bonding apparatus 1 includes a camera 3 as an imaging means, a bonding arm 4 with a capillary 4a attached to the tip, a bonding head 5 that drives the bonding arm 4 up and down, a bonding arm 4 and An XY table 6 as a positioning means for mounting and positioning a bonding means and an imaging means comprising a bonding head 5 in a two-dimensional manner in the X and Y directions, and a bonding stage 8 on which a bonding operation is performed by the bonding head 5. The bonding stage 8 has a heater (not shown) for heating a lead frame or the like on which a plurality of chips are arranged and adhered in the longitudinal direction.
[0019]
As shown in FIG. 1, the bonding apparatus 1 includes an image detection apparatus 10 serving as a detection unit that receives an imaging signal from the camera 3 and detects a fixed point deviation amount of a part to be bonded from image data, and an image detection apparatus. A monitor 11 that receives the video output from 10, a control device 12 that includes a microprocessor 12 a, a manipulator 15 that outputs a signal for manually moving the XY table 6 to the control device 12, A driving device 12 is provided that issues a driving signal to the bonding head 5 and the XY table 6 in response to the command signal.
[0020]
As shown in FIG. 1, the camera 3 mounted on the bonding head 5 is attached at a position away from the capillary 4a. The distance between the optical axis of the optical system of the camera 3 and the axis of the bonding tool 4a is referred to as camera tool offset (hereinafter referred to as CTD). Usually, the CTD is set to be an integral multiple of the chip interval on the lead frame in the same direction as the transport direction of the transport device 7.
[0021]
The self-teach performed in advance prior to the bonding operation will be described. The self-teach is for setting various conditions related to bonding positions on the pads to be bonded and leads.
[0022]
As shown in FIG. 1, the operator operates the manipulator 15 while viewing the image based on the imaging signal from the camera 3 on the monitor 11 to move the XY table 6, and is provided on the screen of the monitor 11. The intersection of the cross lines 11a is aligned with at least one fixed point on the chip. The position of the XY table 6 when the intersection of the cross lines 11a shown in FIG. 1 is aligned with one fixed point on the chip by self-teaching is referred to as a reference point a. Further, the operator operates the manipulator 15 to move the camera 3 on the XY table 6, and the intersection of the cross lines 11a provided on the screen of the monitor 11 is set as a fixed point on the chip, a pad bonding point, and a lead. Hereinafter, the operation of matching the bonding points and the like will be referred to as “matching”. Note that the position of the camera 3 and the coordinate position of the XY table 6 are different, and the alignment is when viewed from the screen of the monitor 11, and the position coordinate of the XY table 6 at that time is the reference point a. .
[0023]
Then, the position coordinates of the reference point a of the XY table 6 at a fixed point on the chip are stored in a memory (storage device) in the control device 12, and in the window 11b on the monitor 11 at the reference point a of the XY table 6 An image centered on a fixed point of the chip is stored in the memory (storage device) 12b of the image detection apparatus 10 as a reference pattern.
[0024]
The above-described alignment at the reference point a is the alignment of a fixed point on the chip, but in addition, the alignment is performed at one fixed point on the lead frame . The position of the XY table 6, which is a fixed point set on the lead frame by self-teaching , is set as a reference point c.
[0025]
The position coordinates of the reference point c of the XY table 6 are stored in the memory 12b in the control device 12, and the fixed point on the lead frame in the window 11b on the monitor 11 at the reference point c of the XY table 6 is centered. Is stored in the memory of the image detection apparatus 10 as a reference pattern.
[0026]
Although the above-described self-teach is an example in which one reference point is set on the chip, two reference points may be set on the chip, and the lead frame transport mode and lead size may be set. For example, the reference point on the lead frame may not be provided. The setting of the reference point is appropriately determined according to the type of chip, the conveyance form, and the like.
[0027]
With the above operation, the reference points of the chip and the lead, and the reference patterns at the reference points are stored in the memory 12b of the control device 12 and the memory of the image detection device 10.
[0028]
Next, the camera 3 on the XY table 6 is moved to align the bonding positions of the pads and leads to be bonded. Thereafter, the pads and leads are aligned sequentially, and all pads and leads are aligned. The position coordinates of the bonding points of the pads and leads are stored in the memory 12b in the control device 12.
[0029]
Next, creation of a pre-detection table for simultaneously detecting the chip shift amount and bonding based on the bonding position coordinates of the pad obtained by self-teaching will be described with reference to the flowchart shown in FIG.
[0030]
The pre-detection table creation program shown in FIG. 2 is stored in the memory 12b in the control circuit 12 shown in FIG. 1, and the pre-detection table is created when the microprocessor 12a executes the program.
[0031]
As shown in FIG. 2, first, the chip number n and the detection chip number a are initialized (step S1). The chip number is a number for specifying a chip in the bonding area, and is obtained by assembling the chips in ascending order in the bonding order. For example, a chip number n = 1 indicates a chip to be bonded first. The detection chip number indicates a chip number for detecting a deviation amount with respect to a chip number n indicating the bonding order.
[0032]
Next, it is checked with reference to the previous detection table whether the detection chip number a has been registered in the previous detection table (step S2). When the detection chip number a has been registered in the previous detection table, the process proceeds to step S7, and a value obtained by adding 1 to the detection chip number a is set as the detection chip number a (step S7). When the detection chip number a is not registered in the previous detection table, the bonding position coordinate data of the chip number n and the bonding position coordinate data of the detection chip number a are read from the memory 12b, and the chip number n and the detection chip number a are detected. (Step S3), it is checked whether the capillary 4a is at the bonding position of the chip number n and the camera 3 can image the chip of the detection chip number a (step S4). The check is performed by determining whether the distance and direction calculated in step S3 are values within a predetermined range based on the CTD. If the chip with the detection chip number a cannot be captured by the camera 3, it is determined whether the detection chip number a is the last chip (step S5). If the chip is not the final chip, the process proceeds to step S7. . In the case of the final chip, since there is no chip that can be imaged by the camera 3 at the bonding position of the chip of chip number n, “0 (zero)” is written in the previous detection table (step S6), and the process proceeds to step S9. . If the chip with the detection chip number a can be picked up by the camera 3, the detection chip number “a” is written in the previous detection table (step S8).
[0033]
Next, it is checked whether the chip number n is the last chip (step S9). If it is not the last chip, a value obtained by adding 1 to the chip number n is set as the chip number n, and the detection chip number a Initialization is performed (step S10), and the process proceeds to step S2.
[0034]
In the case of the last chip, an undetected chip is extracted from the previous detection table (step S11). The detection order of undetected chips extracted from the previous detection table is determined (step S12). The detection order of undetected chips is determined so that the moving distance of the bonding head 5 is the shortest based on the arrangement of the chips on the CTD and the lead frame. Thus, the previous detection table is created.
[0035]
The above-described pre-detection table will be described by taking, as an example, a component to be bonded formed of chips that are attached in a matrix on a substrate. FIG. 3 shows a bonded component made of chips attached in a matrix. FIG. 4 shows a pre-detection table in which the part to be bonded shown in FIG. 3 is created by the pre-detection table creation program. The distance between the capillary 4a and the camera 3 is set at an interval of one chip in the X direction. As shown in FIG. 4, the chip number corresponding to each chip number stored in the table indicating the bonding order is stored in the pre-detection table. At the time of bonding with the chip number c1 shown in the bonding order table, the chip number c8 is imaged by the camera 3 from the previous detection table. Thereafter, the detection operation is performed simultaneously until the bonding of the chip number c12. Note that the chip numbers that are not detected simultaneously with bonding from the previous detection table are c1, c2, c3, and c4, and the chip numbers that are only bonded are c13, c14, c15, and c16.
[0036]
Next, the bonding sequence will be described with reference to the flowchart shown in FIG. First, a chip that performs only detection is searched from the previous detection table stored in the memory 12b of the control device 12 (step S20). The chip detection position data is read from the memory 12b from the chip number of the previous detection table (step S21), and the camera 3 is moved to the chip detection position based on the chip detection position data (step S22). After moving to the chip detection position, the image detection apparatus 10 captures an image from the camera 3, detects the chip shift amount, and outputs the shift amount data to the control device 12 (step S23). It is checked whether or not the detection of the deviation amounts of all the chips for detection only has been completed (step S24), and if not completed, the process proceeds to step S21 and the data of the next chip detection position from the previous detection table. Is read. When the detection of all the chip shift amounts only for detection is completed, the bonding position data is read from the memory 12b, the position correction is performed based on the chip shift amount data, and the tool offset is added to the position corrected data. Then, the XY table 6 is moved based on the added data. After the movement of the XY table 6 is completed, the capillary 4a is positioned on the pad of the chip to be bonded, and the camera 3 is positioned on the chip specified by the previous detection table. The chip 3 is imaged by the camera 3 at the bonding position (step S25).
[0037]
Next, the capillary 4a is lowered by the bonding head 5 to connect the wire to the pad (step S26). The image processing apparatus detects a chip shift amount from the chip image data from the camera 3 (step S27). Next, the XY table 6 is moved to the bonding position on the lead, and the capillary 4a is lowered by the bonding head 5 to connect the wire to the lead (step S28). Next, it is checked whether the operation of all the chips that perform the simultaneous operation of detection and bonding is completed (step S29). If the operations of all the chips that perform the simultaneous detection and bonding operations have not been completed, the process proceeds to step S25 to move to the next bonding position. When the operations of all the chips that perform simultaneous detection and bonding are completed, unbonded chips are bonded (step S30). At this time, since the deviation amount of the chip to be bonded has already been detected, the detection operation is not performed. It is checked whether bonding of all chips has been completed (step S31). If bonding of all chips has not been completed, the process proceeds to step S30 to bond unbonded chips. When all the chips have been bonded, the lead frame is transported by the transport device 7 (step S32).
[0038]
FIG. 6 shows a table of chip detection order and bonding order shown in FIG. As shown in FIG. 6, in sequence 1 to 4, detection operations are performed in the order of chip numbers c4, c3, c2, and c1, and in sequence 5, chip number c8 is detected when chip number c1 is bonded. Detection and bonding are performed at the same time, and the remaining chip numbers c13, c14, c15, and c16 are bonded from sequence 17. As a result, the movement of the XY table 6 (shown by the arrow line in FIG. 3) can be optimized as shown in FIG. 3, so that the bonding process time can be shortened and the number of parts to be bonded produced. Can be increased.
[0039]
In the bonding method and bonding apparatus described above, the case where the distance (CTD) between the capillary and the camera is set at an interval of one chip in the X direction has been described, but the chip attached to the lead frame, the substrate, or the like. The present invention can also be applied when the CTD is set to an integral multiple of the interval.
[0040]
Further, in the bonding method and bonding apparatus according to the present invention, applicable chips are not limited to LEDs and transistors, but may be ICs having a small chip size, for example.
[0041]
【The invention's effect】
As described above, according to the bonding method and the bonding apparatus of the present invention, by determining the optimum detection order based on the bonding order, there is no wasteful movement of the XY table, and the number of parts to be bonded produced. Can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a bonding apparatus.
FIG. 2 is a flowchart for determining the order of chip detection.
FIG. 3 is a diagram showing a configuration of a chip attached in a matrix on a substrate as a part to be bonded;
4 is a view showing a front detection table of chips attached in a matrix form shown in FIG. 3; FIG.
FIG. 5 is a flowchart of a bonding sequence.
6 is a view showing a bonding process of chips attached in a matrix on the substrate shown in FIG. 3;
FIG. 7 is a diagram showing a conventional detection and bonding process.
8A is a configuration diagram of a component to be bonded made of chips attached in a matrix on a substrate, and FIG. 8B is a diagram illustrating a bonding component detection and bonding process shown in FIG. 8A. is there.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bonding apparatus 3 Camera 4 Bonding arm 4a Capillary 5 Bonding head 6 XY table 7 Conveyance apparatus 8 Bonding stage 10 Image detection apparatus 11 Monitor 11a Cross line 11b Window 12 Control apparatus 12a Microprocessor 12b Memory 13 Drive apparatus 15 Manipulator 20 Chip 30 Lead frame (substrate)

Claims (2)

Bonding means for bonding to a part to be bonded, positioning means for positioning by bonding the bonding means relative to the part to be bonded two-dimensionally, and the part to be bonded mounted on the positioning means Chip displacement amount in a bonding apparatus comprising: an image pickup means for picking up images; a detection means for detecting a shift amount of a fixed point of the part to be bonded from image data from an image pickup signal of the image pickup means; and a control means including a microprocessor. A bonding method that performs detection and bonding simultaneously,
The control means, as a part to be bonded that can be imaged by the imaging means when the bonding means is located at the bonding position, from the coordinates of the bonding position set in advance and the offset amount between the bonding means and the imaging means. A step of calculating a chip, a step of determining the detection order of the chip corresponding to the order of the bonding operation, and a pre-detection table storing the detection order of the chip corresponding to the order of the bonding operation are automatically created and stored. A process,
During the bonding operation, the corresponding chip stored in the previous detection table is imaged by the imaging unit, and the deviation amount of the chip is detected by the detection unit from the image data of the imaging unit. Bonding method. Bonding means for bonding to a part to be bonded, positioning means for positioning by bonding the bonding means relative to the part to be bonded two-dimensionally, and the part to be bonded mounted on the positioning means A detecting means for detecting a deviation amount of the fixed point of the part to be bonded from image data from an imaging signal of the imaging means, and a control means including a microprocessor. A bonding apparatus that performs bonding at the same time,
The control means, as a part to be bonded that can be imaged by the imaging means when the bonding means is located at the bonding position, from the coordinates of the bonding position set in advance and the offset amount between the bonding means and the imaging means. A means for calculating the chip, a means for determining the detection order of the chip corresponding to the order of the bonding operation, and a pre-detection table storing the detection order of the chip corresponding to the order of the bonding operation are automatically created and stored. Means and
During the bonding operation, the corresponding chip stored in the previous detection table is imaged by the imaging unit, and the deviation amount of the chip is detected by the detection unit from the image data of the imaging unit. Bonding equipment.

Images