JP2002151527A - Automatic die bond precision correction system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic die bond precision correction system which can automatically correct the precision in bonding under operation state of a facility without being influenced by the state change of parts in process. SOLUTION: This system picks up the position judgment images of a chip 1 and a package 2 to a reference plane with inspection image pickup cameras 5a and 5b, and processes the images with image processing circuits 17a and 17b, and stores it as position judgment image data in an image data memory 10, and picks up the inspection images of the parts C bonded in set positions with an inspection image pickup camera 5c, and processes the images with an image processing circuit 17c, and stores them in an image data memory 10 as inspection image data, and stores the basic data consisting of position judgment image data and inspection image data several times, and operates the offset quantity ΔS for positional correction of a chip 1 and a package 2 by the median data of bond accuracy data obtained from a plurality of basic data, and automatically feeds back and corrects the positional set value of at least one hand of the chip 2 and the package 2, and thereby can control the bond precision with high precision under facility operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic die bond accuracy correction system for automatically correcting die bond accuracy.

[0002]

2. Description of the Related Art In a die bonding apparatus, prior to wire bonding, a die (die), which is a strip of a semiconductor or an insulator, is placed one by one on a metal frame (lead) on which a die pad for fixing the die and a lead wire are formed. Frame),
A die pad and an external conductor are formed, and bonding to a bonding target such as a package in which a die to be connected is protected and arranged inside is performed with a specified accuracy while being positioned. Then, a final semiconductor product is assembled based on a bonding target such as a lead frame or a package to which the die is bonded. Where the die
Although it is also called a pellet or a chip, it is usually called a chip.
In the following description, it is called a chip. By the way, if this chip is not accurately bonded to a lead frame or package at a preset position,
It may have a negative effect on the operation of the final semiconductor product.For example, if the final semiconductor product is an electronic still camera, if the bonding accuracy of the CCD element chip to the package is not within the standard, The quality of the captured image formed by the electronic still camera may be reduced.

Conventionally, in order to realize bonding accuracy within a standard, an inspector performs a sampling inspection on a lead frame or a package at the beginning of a lot flow, thereby detecting a measured value of the bonding accuracy, and The difference from the value is calculated as an offset value, and the bonding accuracy is corrected at the bonding position based on the obtained offset value. Then, the bonding accuracy is measured based on the image processing based on the captured image of the component after the bonding, and it is determined whether or not the accuracy is within the standard, and the non-standard component is treated as a defective product.

[0004]

Since the conventional bonding accuracy detection as described above is basically performed by an inspector, the inspection results tend to vary, and the correction of the bonding accuracy at the bonding position by the offset value is difficult. May not work properly. In addition, since the operation of the equipment is stopped during the detection of the bonding accuracy, a smooth bonding operation is not performed, and further, the outer shape, brightness, and saturation of the chip may be slightly changed during the progress of the bonding process. There is a possibility that the correspondence between the determination of the bonding accuracy obtained by the image processing of the captured image and the detection value of the bonding accuracy obtained by the sampling inspection at the beginning of the lot flow may be broken, and the offset value obtained by the conventional method may be lost. In the correction, sufficient correction of the bonding accuracy cannot be performed.

The present invention has been made in view of the above-mentioned current situation of the correction of bonding accuracy, and has as its object to always provide a high-precision bonding accuracy without being affected by a change in the state of parts during the process. It is an object of the present invention to provide a die bonding accuracy automatic correction system capable of appropriately performing automatic correction under the operating state of equipment.

[0006]

According to a first aspect of the present invention, there is provided a position setting device for setting a two-dimensional relative position of a chip and a bonding object to which the chip is bonded with respect to a reference plane. Means, a position detection imaging means for imaging a position determination image at the set position of the chip and the bonding object for which the two-dimensional relative position has been set by the position setting means, and a position setting by the position setting means. In the performed state, an inspection image capturing unit that captures an inspection image of the chip and the bonding target bonded to each other, and position determination image data obtained by performing image processing on a position determination image from the position detection imaging unit, Basic data storage means for storing inspection image data obtained by performing image processing on the inspection image from the inspection image imaging means as basic data corresponding to each other. A correction data calculating means for calculating correction data for controlling the position setting means based on a plurality of preset basic data; and the position setting based on the correction data calculated by the correction data calculating means. And a correction control means for performing a feedback correction control on the means to finely adjust the two-dimensional relative position of at least one of the chip and the bonding object.

According to such means, the position setting means sets the two-dimensional relative position with respect to the reference plane of the chip and the bonding object to which the chip is bonded, and thus sets the two-dimensional relative position. Inspection of the chip and the bonding target to be bonded to each other in a state where the position determination image at the set position is captured by the position detection imaging unit for the set chip and the bonding target, and the position setting is performed by the position setting unit. An image is captured by the inspection image imaging unit, and position determination image data obtained by performing image processing on the position determination image from the position detection imaging unit, and inspection image data obtained by performing image processing on the inspection image from the inspection image imaging unit, The data is stored in the basic data storage means as basic data corresponding to each other. Then, correction data for correcting and controlling the position setting means is calculated by the correction data calculating means based on a plurality of preset basic data, and the correction control means is calculated based on the correction data calculated by the correction data calculating means. Thus, the two-dimensional relative position of at least one of the chip and the bonding object is automatically and finely adjusted by the feedback correction under the operating state of the equipment by the feedback correction control of the position setting means.

[0008] Similarly, in order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the invention, the correction data calculating means uses the median value of the plurality of basic data to perform the correction. It is characterized by calculating data.

According to such a means, the correction data calculating means calculates the correction data using the median value of the plurality of basic data, whereby the operation according to the first aspect of the present invention is executed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an explanatory diagram showing a whole configuration including a block diagram of a main part configuration of the present embodiment, and FIG. 2 is a flowchart showing an operation of the present embodiment.

In this embodiment, as shown in FIG. 1, a central control unit 6 for controlling the entire operation is provided, and the central control unit 6 is connected via a bus B to a ROM 7 in which a control program is stored. A RAM 8 in which various data are written and read during the control operation, an image data memory 10 in which image data is stored, a correction data operation circuit 11 in which correction data is calculated, and a control signal for correction control. Correction control circuit 12 is connected. Similarly, a die bonder driving circuit 1 that outputs a die bonding driving signal to the central control unit 6 via a bus B
3. A quality judging circuit 14 for judging the quality of the die-bonded component, and a notifying device 15 for notifying the quality failure based on the judgment result of the quality judging circuit 14 are connected.

On the other hand, in the present embodiment, a driver that sets the two-dimensional relative position of the chip 1 with respect to the reference plane of the stage 3 by movement in the X-axis direction and Y-axis direction and rotation about the axis. 16a, and the driver 16a
Is provided, an inspection imaging camera 5a for imaging the chip 1 in which the two-dimensional relative position is set, an output terminal of the correction control circuit 12 is connected to an input terminal of the driver 16a, and an output terminal of the inspection imaging camera 5a is The image processing circuit 17a is connected to an image processing circuit 17a that performs image processing on a captured image, and an output terminal of the image processing circuit 17a is connected to a first input terminal of the image data memory 10. Similarly, a driver 16b is provided for setting the two-dimensional relative position of the package 2 with respect to the reference plane of the stage 3 by movement in the X-axis direction and Y-axis direction and rotation about the axis. 1
6b, an inspection imaging camera 5b for imaging the package 2 in which the two-dimensional relative position is set is provided, an output terminal of the correction control circuit 12 is connected to an input terminal of the driver 16b, and an output terminal of the inspection imaging camera 5b is provided. Are connected to an image processing circuit 17b that performs image processing on a captured image, and an output terminal of the image processing circuit 17b is connected to a second input terminal of the image data memory 10.

In this embodiment, a die bonder 18 for bonding a chip 1 and a package 2 having a two-dimensional relative position with respect to a reference surface of a stage 3 to each other is provided.
Is provided, and an output terminal of the die bonder driving circuit 13 is connected to an input terminal of the die bonder 18. Then, the chip 1 and the package 2 bonded to each other
Imaging camera 5 for capturing an inspection image of component C made of
c is provided, and the output terminal of the inspection and imaging camera 5c is
The input terminal of the image processing circuit 17c that performs image processing is connected, and the output terminal of the image processing circuit 17c is connected to the third input terminal of the image data memory 10.

The operation of the present embodiment having such a configuration is described below.
This will be described according to the flowchart of FIG. When the die bonding operation is started, a preset initial position set value is set in the chip 1 and the package 2 by a command of the central control unit 6, and in step S1 of the flowchart of FIG. 1 is XY
The coordinate is moved to the set coordinate position of the coordinate, rotated by a predetermined angle θ1 about the axis, and the initial position of the chip 1 is set. Next, the process proceeds to step S2, where the driver 16b
As a result, the package 2 is moved to the set coordinate position of the XY coordinates, rotated by a predetermined angle θ2 about the axis, and the initial position of the chip 1 is set. Then, a position determination image of the chip 1 whose initial position has been set is captured by the inspection imaging camera 5a, and the captured position determination image is
After the image processing is performed by the image processing circuit 17a, the image data is stored in the image data memory 10. Similarly, the inspection imaging camera 5b
Thus, the position determination image of the package 2 whose initial position has been set is captured, and the captured position determination image is subjected to image processing by the image processing circuit 17b, and is then processed by the image data memory 10.
Is stored in

Next, in step S3, the die bonder drive circuit 13 operates according to a command from the central control unit 6, and the die bonder 18 driven by the drive signal from the die bonder drive circuit 13 causes the die bonder 18 to move with respect to the reference surface of the stage 3. Chip 1 and package 2 with initial position set
Are bonded to each other. Then, step S4
To the package 2 by the inspection imaging camera 5c.
An inspection image of the component C having the chip 1 bonded thereto is captured, and the captured inspection image is stored in the image data memory 10 in step S5 after being subjected to image processing by the image processing circuit 17c. In this case, the instruction of the central control unit 6 causes the image data memory 10 to store the position-determined image data of the image-processed chip 1, the position-determined image data of the image-processed package 2, and the part C of the image-processed component C The inspection image data is stored as basic data associated with each other, and a difference value between actual measurement value data obtained from the inspection image data and set value data obtained from the image determination image data is calculated as bond accuracy data Db. Is stored. In accordance with a command from the central control unit 6, a plurality of sets of basic data are repeatedly stored for a predetermined number of components C to be subjected to bonding processing in the manufacturing process.

Further, in this embodiment, every time the inspection image data of the part C is inputted to the image data memory 10, the quality judgment circuit 14 is operated by the command of the central control unit 6, and the quality judgment circuit 14 It is determined whether or not the inspection image data is within the predetermined allowable standard range, and if it is determined that the inspection image data is not within the allowable standard range, the central control unit 6
The notification of the occurrence of a defective product is issued from the notification device 15 in response to the command.

The above-described basic data storage operation is performed as follows:
Step S6 indicates that the predetermined number of times has been reached.
Is confirmed in step S7 by the correction data calculation circuit 11 operated by the command of the central control unit 6.
, The median data Db (1/2) n of the bond precision data Db1 to Dbn from the plurality of basic data stored in the image data memory 10 is read, and the read median data Db (1/2) ) The correction data is calculated based on n. In this calculation, the current offset amount is
As S0, an offset amount △ S as correction data is calculated by the following equation.

△ S = △ S0−Db (１ ／) n

Assuming that the detected position data of the package 2 is Pd and the detected position data of the sensor 1 is Sd, the package correction amount Pam and the sensor correction amount Sam are respectively calculated by the following equations.

Pam = Pd + △ S Sam = Sd + △ S

FIG. 2 shows a case where the feedback correction of only the package 2 is performed. In step S8, the position of the package 2 is automatically corrected by the offset ΔS.

Thus, according to the present embodiment,
The position determination images for determining the setting positions of the chip 1 and the package 2 with respect to the reference plane of the stage 3 are captured by the inspection imaging cameras 5a and 5b, respectively, and the image processing circuit 1
The parts made up of the chip 1 and the package 2 are subjected to image processing in 7a and 17b, stored in the image data memory 10 as position determination image data, and bonded to each other at a set position with respect to the reference surface of the stage 3 by the inspection imaging camera 5c. The inspection image of C is taken and the image processing circuit 17
Image processing is performed in step c, and the image data is stored in the image data memory 10 as inspection image data, and inspection image data corresponding to the position determination image data is stored a plurality of times as basic data.
Then, median data of the bond accuracy data is read from the plurality of basic data, and an offset amount ΔS for correcting the set position of the chip 1 and the package 2 is calculated based on the read median data, 1 and package 2
Since feedback correction control is performed on at least one of the position settings, the bonding accuracy can be automatically controlled and set to a predetermined value within a standard range with high accuracy while the equipment is operated. According to the measurements by the inventors, it has been confirmed that the accuracy control can be performed with a high accuracy of ± 30 μm in the case where the accuracy control within ± 50 μm has conventionally been the limit.

[0023]

According to the first aspect of the present invention, the two-dimensional relative position of the chip and the bonding object to which the chip is bonded with respect to the reference plane is set by the position setting means. For the chip and the bonding target for which the relative position is set, a position determination image at the set position is captured by the position detection imaging unit,
In a state where the position setting is performed by the position setting unit, the inspection image of the chip and the bonding target to be bonded to each other is captured by the inspection image capturing unit, and the position determination image from the position detection capturing unit is subjected to the image processing. The determination image data and the inspection image data obtained by performing image processing on the inspection image from the inspection image imaging unit are stored in the basic data storage unit as basic data corresponding to each other. Then, correction data for correcting and controlling the position setting means is calculated by the correction data calculating means based on a plurality of preset basic data, and the correction control means is calculated based on the correction data calculated by the correction data calculating means. By performing the feedback correction control of the position setting means, the two-dimensional relative position of at least one of the chip and the bonding target is finely adjusted. As described above, the correction data stored in the basic data storage means and based on a plurality of sets of basic data composed of the position determination image data and the inspection image data corresponding to each other, based on the correction data calculated by the correction data calculation means, The position setting means is corrected and controlled, and at least one of the two-dimensional relative position of the chip and the bonding target is feedback corrected with an offset value based on the inspection image data, and in a state where the equipment is operated, the bonding accuracy is determined. It is possible to control and set a predetermined value within a standard range with high accuracy.

According to the second aspect of the present invention, the effect of the first aspect of the present invention is realized by the correction data calculating means calculating the correction data using the median of a plurality of basic data. Becomes possible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration including a block diagram of a main configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the embodiment.

[Explanation of symbols]

1. chip, 2. package, 3. stage, 5.
a to 5c inspection camera, 6 central control unit, 10 image data memory, 11 correction data operation circuit, 12 correction control circuit, 13 die bonder drive circuit, 14 quality judgment Circuit, 15 ... Notifier, 16
a, 16b ··· driver, 17a to 17c ··· image processing circuit, 18 ··· die bonder.

Claims (2)

[Claims] 1. A position setting means for setting a two-dimensional relative position of a chip and a bonding object to which the chip is to be bonded with respect to a reference plane; and the chip having the two-dimensional relative position set by the position setting means; Position detection imaging means for imaging a position determination image of the bonding object at the set position; and an inspection image of the chip and the bonding object bonded to each other in a state where the position setting is performed by the position setting means. Inspection image imaging means for imaging, position determination image data obtained by performing image processing on the position determination image from the position detection imaging means, and inspection image data obtained by performing image processing on the inspection image from the inspection image imaging means, Basic data storage means for storing basic data corresponding to each other; and a position setting means based on a plurality of preset basic data. Correction data calculating means for calculating correction data for correcting and controlling the position setting means based on the correction data calculated by the correction data calculating means, and performing feedback correction control on the position and the bonding object. And a correction control means for finely adjusting at least one of the two-dimensional relative positions. 2. A system according to claim 1, wherein said correction data calculating means calculates said correction data using a median of said plurality of basic data.