JP2004146776A - Machine and method for mounting flip-chip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machine for mounting flip-chips capable of stabilizing the quality by improving the bonding precision, shortening the working time required for the inspection, and improving the productivity. <P>SOLUTION: The position data is obtained by picking up the image and performing image processing of a chip 9 for inspection formed with a chip side recognition mark 8 previously sucked and held on a bonding head 1 and a substrate 11 for inspection formed with a substrate side recognition mark 10 supported by a substrate supporting table 2 by a first image pickup means 6. From the position data, thereafter, the chip 9 for inspection is bonded to the substrate 11 for inspection by correcting the position of the bonding head 1 and the substrate supporting table 2. The substrate of a semiconductor chip is mounted after correcting the position of the bonding head 1 and the substrate supporting table 2 again by the position data obtained by picking up the image and performing image processing of the position deviation of chip 9 for inspection and the substrate 11 for inspection by a second pickup means 7. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flip chip mounting apparatus and a mounting method for flip chip mounting a semiconductor chip on a substrate.
[0002]
[Prior art]
A flip chip bonder for flip-chip mounting a semiconductor chip on a substrate will be described. When flip-chip mounting a semiconductor chip on a board, it is necessary to align the connection terminals of the chip with the lands of the board and bond them. Therefore, check the mounting position accuracy of the flip-chip bonder before mounting. Things are going on.
[0003]
For example, in FIG. 5, in a state where an inspection chip (for example, a glass chip) 52 is sucked and held by a bonding head 51 and the inspection substrate 53 is held on a stage 54 that supports an inspection substrate (for example, a glass substrate) 53, The position of the chip 52 and the substrate 53 are imaged by the position correcting camera 55. A vernier (vernier scale) 57 is engraved on the inspection chip 52 and the inspection substrate 53 so that the amount of misalignment between them can be confirmed. The images of the chip surface and the substrate surface captured by the position correcting camera 55 are subjected to image processing in a control unit such as a controller (not shown) to calculate corrected position data. After the position of the stage 54 in the XY direction is corrected based on the corrected position data and the position of the bonding head 51 in the θ direction is corrected, the bonding head 51 is moved down toward the stage 54 to Is bonded to the inspection substrate 53.
[0004]
Next, the inspection substrate 53 to which the inspection chip 52 has been bonded is removed from the stage 54, and the image of the vernier 57 is enlarged using a microscope 56 or the like. I was verifying. After the confirmation, if the displacement is within the allowable error range, the semiconductor chip is mounted on the substrate with the position of the bonding head 51 and the stage 54 set. Further, when the position is outside the allowable error range, the positions of the bonding head 51 and the stage 54 in the XY directions are corrected again, and then the semiconductor chip is mounted on the substrate.
[0005]
[Patent Document 1]
JP-A-7-283272
[Problems to be solved by the invention]
Since the verification work of the positional deviation error between the inspection chip 52 and the inspection substrate 53 is performed off-line, it takes a long time for the inspection, and since an operator visually checks the error, an artificial reading error easily accumulates. However, there is a problem that bonding accuracy may be reduced.
[0007]
An object of the present invention is to solve the above-mentioned problems of the prior art, stabilize the quality by improving the bonding accuracy, shorten the work time required for inspection, and improve the flip-chip mounting apparatus and the flip-chip mounting method that can improve the productivity. To provide.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configuration.
In a flip-chip mounting apparatus for flip-chip mounting a semiconductor chip on a substrate, an up-down and rotatable bonding head for sucking and holding the semiconductor chip and bonding the semiconductor chip to the substrate, and a substrate support table for supporting the substrate are provided by X-axis. First imaging for moving a table moving mechanism provided so as to be movable in the Y direction, moving forward and backward between the bonding head and the substrate support table, imaging the chip surface and the substrate surface, and detecting a displacement between the chip surface and the substrate surface. Means, and a second image pickup means provided below the substrate support table, for picking up an image of the substrate to which the semiconductor chip is bonded, and for detecting a positional shift between the two. Inspection chip with chip-side recognition mark formed and board-side recognition mark supported on board support table formed The inspection chip is superimposed on the inspection substrate by correcting the positional deviation of the bonding head and the substrate support table from the position data obtained by imaging the inspected substrate with the first imaging means and performing image processing. The position of the bonding head and the substrate support table is corrected again from the position data obtained by imaging the inspection chip and the inspection substrate by the second imaging means and performing image processing, and then correcting the position of the semiconductor chip. It is characterized in that mounting on a substrate is performed.
[0009]
Further, in the flip chip mounting method for flip chip mounting a semiconductor chip on a substrate, an inspection chip on which a chip side recognition mark previously formed by suction and held by a bonding head is formed, and a substrate side recognition mark supported on a substrate support table. A first imaging step of imaging the formed inspection substrate, and a positional deviation of the bonding head and the table moving mechanism from position data obtained by performing image processing on the image data captured in the first imaging step. A first position correction step of correcting the inspection chip, an inspection bonding step of moving the bonding head to overlay the inspection chip on the inspection substrate, and a second imaging step of imaging the overlapped inspection chip and the inspection substrate. From the position data obtained by performing image processing on the image data captured in the second imaging process And a second position correction step of correcting a displacement between the positioning head and the table moving mechanism, and holding the semiconductor chip on the bonding head and mounting the substrate on the substrate supplied to the substrate support table. It is characterized by the following.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1 and 2 are explanatory views showing a work for inspecting a position shift of the flip chip mounting apparatus, FIG. 3 is a block diagram of a control system, and FIG. 4 is an explanatory view of a chip-side recognition mark and a board-side recognition mark.
[0011]
First, a schematic configuration of a flip chip mounting apparatus will be described with reference to FIG.
Reference numeral 1 denotes a bonding head, which holds a semiconductor chip by suction and bonds the semiconductor chip to a substrate. The bonding head 1 is rotatably provided by a vertical movement mechanism (ball screw, servomotor, etc.) and a rotation mechanism (rotation motor) (not shown).
[0012]
Reference numeral 2 denotes a substrate supporting table for supporting the substrate, which is mounted on the table moving mechanism 3. The table moving mechanism 3 includes an X direction moving stage 4 and a Y direction moving stage 5, and the substrate support table 2 is mounted on the X direction moving stage 4.
Reference numeral 6 denotes a mounting position correcting camera (for example, a CCD camera), which is a first imaging means, which moves forward and backward between the bonding head 1 and the substrate support table 2 to image the chip surface and the substrate surface, and positions both of them. Detect the shift. The mounting position correcting camera 6 is provided with camera lenses 6a and 6b on the upper and lower sides, and a control unit, which will be described later, calculates chip and substrate positional deviation data based on images captured by the camera lenses 6a and 6b. Thus, the position of the bonding head 1 in the θ direction is corrected, and the position of the substrate support table 2 in the XY direction is corrected.
[0013]
Reference numeral 7 denotes a bonding inspection camera (for example, a CCD camera) which is a second imaging unit. The bonding inspection camera is provided on the X-direction moving stage 4 below the substrate support table, and images the substrate to which the semiconductor chip has been bonded by the bonding head 1 to detect a displacement between the two. The image picked up by the bonding inspection camera 7 is subjected to image processing by a control unit described later, and a positional shift between the two is detected.
[0014]
In this embodiment, as shown in FIG. 4, an inspection chip (for example, a glass chip) 9 on which a chip-side recognition mark (for example, a graphic mark) 8 is formed in advance and a substrate-side recognition mark (for example, a graphic mark) 10 are formed. After the position of the bonding head 1 and the substrate support table 2 is corrected using the inspection substrate (for example, a glass substrate) 11, the semiconductor chip is mounted on the substrate. A vernier (vernier scale) 12 is engraved on the inspection chip 9 and the inspection substrate 11 by etching or the like, and is used for position correction.
[0015]
Specifically, the inspection chip 9 previously held by suction on the bonding head 1 and the inspection substrate 11 supported on the substrate support table 2 are imaged by the mounting position correction camera 6 and image processing is performed. Based on the position data obtained from the deviation of the vernier 12, the position of the bonding head 1 is corrected in the θ direction, the position of the substrate support table 2 is corrected in the X and Y directions, and then the inspection chip 9 is transferred to the inspection substrate 11. Perform bonding.
[0016]
Next, an image of the inspection substrate 11 on which the inspection chip 9 is superimposed is picked up by the bonding inspection camera 7, image processing is performed, and the amount of displacement between the chip-side recognition mark 8 and the substrate-side recognition mark 10 is determined based on the position data. calculate. After the positions of the bonding head 1 and the substrate support table 2 are corrected again from the obtained position data, the semiconductor chip is mounted on the substrate. The substrate support table 2 is provided with a fixing portion for the inspection substrate 11 separately from a setting portion for mounting the semiconductor chip on the substrate. The fixed portion of the inspection substrate 11 is provided on a part of the substrate support table 2 (for example, an end of the substrate support table 2), and is imaged by the bonding inspection camera 7 in a state where the inspection chips 9 are overlapped. A transparent portion or an opening is formed so as to be able to. The set portion of the mounting substrate to which the semiconductor chip is bonded is provided near the fixing portion of the inspection substrate 11.
[0017]
In addition, the inspection chip 9 and the inspection substrate 11 are provided with the identification mark provided on the inspection chip 9 and the identification mark provided on the inspection substrate 11 in a state where the inspection chip 9 is overlaid on the inspection substrate 11. Is used to detect mutual positional deviation from the deviation of the recognition mark. Therefore, in order to accurately detect the displacement between the inspection chip 9 and the inspection substrate 11, in a state where the inspection chip 9 is overlaid on the inspection substrate 11, each of the recognition marks is sharp. It needs to be able to be taken as an image. This is because if the edge of the recognition mark is blurred, the position of the recognition mark cannot be accurately specified, and the measurement error increases.
[0018]
The inspection chip 9 and the inspection substrate 11 are provided with a chip-side identification mark 8 and a substrate-side identification mark 10 on surfaces facing each other. In a state where the inspection chip 9 and the inspection substrate 11 are overlapped, the chip-side recognition mark 8 and the substrate-side recognition mark 10 are seen through from below the inspection substrate 11 by the bonding inspection camera 7. With respect to the recognition mark 10, a portion (back surface) in contact with the inspection substrate 11, and with respect to the chip-side recognition mark 8, a portion (front surface) exposed on the outer surface of the inspection chip 9 is visually recognized.
[0019]
In the present embodiment, in order to make these chip-side recognition marks 8 and substrate-side recognition marks 10 clearly visible, the recognition marks are formed by chrome evaporation or the like so that the front and back surfaces are mirror-finished. The front and back surfaces of the recognition mark mean the side in contact with the base material and the side exposed on the front surface of the base material.By making the front and back surfaces of the recognition mark mirror surfaces, it is possible to obtain a clear reflected image, By accurately detecting the edge portions of the side recognition mark 8 and the board side recognition mark 10, it is possible to accurately detect the displacement of these recognition marks.
As a method of forming the front and back surfaces of the chip-side recognition mark 8 and the substrate-side recognition mark 10 into a mirror surface, a method of forming a recognition mark in a predetermined pattern on the surface of the substrate by vapor deposition or a method of forming a predetermined mark on the surface of the substrate by plating For example, a method of forming a recognition mark on the pattern can be used.
[0020]
Next, a control system of the flip chip mounting apparatus will be described with reference to the block diagram of FIG. The control unit 13 controls the operation of the entire apparatus, and data is input and output through an input / output (I / O) unit 15. The control unit 13 includes a CPU for controlling the operation of each unit, a ROM storing various operation programs, a temporary storage of input data, a RAM used as a work area of the CPU, and image data captured by each camera. , An arithmetic unit for calculating position data from image data, and the like.
[0021]
Various operation commands and various setting values are input to the control unit 13 from an operation unit 14 such as a keyboard and a touch panel, and image data captured by the mounting position correction camera 6 and the bonding inspection camera 7 is transmitted. The control unit 13 also outputs and displays the image data and processed position data on the monitor 16, and drives the θ-axis motor 18, the X-axis motor 19, the Y-axis motor 20, etc. through the motor driver 17. Or to control.
[0022]
Next, a flip chip mounting method will be described with reference to FIGS. 1, 2, and 4. FIG.
In FIG. 1, an inspection chip 9 on which a chip-side recognition mark 8 previously absorbed and held by a bonding head 1 is formed, and an inspection chip 9 on which a substrate-side recognition mark 10 fixed at a predetermined position on the substrate support table 2 is formed. The substrate 11 and the mounting position correcting camera 6 are imaged. (First imaging step).
[0023]
The positions of the bonding head 1 and the table moving mechanism 3 are corrected from the position data obtained by performing image processing on the image data captured by the mounting position correcting camera 6. That is, the image data of the chip and the substrate imaged by the mounting position correcting camera 6 is output while being superimposed on the monitor screen. Then, a positional shift amount is calculated from the overlapping position of the vernier 12. Then, the θ-axis motor 18 is started to correct the position of the bonding head in the θ-direction, and the X-axis motor 19 and the Y-axis motor 20 are started to move the X-direction moving stage 4 and the Y-direction moving stage 5 to support the substrate. The position in the XY direction of the table 2 is corrected (first position correction step).
[0024]
Next, in FIG. 2, the inspection chip 9 is superimposed on the inspection substrate 11 by lowering the bonding head 1. More specifically, the inspection chip 9 is adhered to the inspection substrate 11 while the inspection chip 9 is attracted to the bonding head 1 (inspection bonding step).
[0025]
Next, the inspection chip 9 and the inspection substrate 11 that are superimposed are imaged from the substrate side by the bonding inspection camera 7 (second imaging step). The positional deviation of the bonding head 1 and the table moving mechanism 3 is corrected from the position data obtained by performing image processing on the image data captured by the bonding inspection camera 7.
Specifically, in FIG. 4, the control unit 13 calculates a positional shift in the X-Y-θ direction from the overlapping position of the chip-side recognition mark 8 and the board-side recognition mark 10, and sends it to the control unit 13. The feedback control is performed, and the control unit 13 activates the θ-axis motor 18 through the motor driver 17 to correct the position of the bonding head in the θ direction, and activates the X-axis motor 19 and the Y-axis motor 20 to move the X-direction moving stage 4 and Y The direction moving stage 5 is moved to correct the XY position of the substrate support table 2 (second position correcting step).
[0026]
Then, after returning the inspection chip 9 to a predetermined position in the apparatus by the bonding head 1, the semiconductor chip is sucked and held by the bonding head 1, and the substrate is mounted on the circuit board supplied to the set portion of the substrate support table 2. (Substrate mounting process). When mounting the substrate, for example, the X-direction moving stage 4 is moved in the X direction until the setting position of the substrate support table 2 is located directly below the bonding head 1 before the mounting. According to this mounting method, an error at the time of flip chip mounting can be suppressed to ± 2 μm or less.
[0027]
If the above-described flip-chip mounting apparatus and flip-chip mounting method are used, before and after the inspection chip 9 is mounted on the inspection substrate 11, both images are taken, position data is detected, and the positional deviation amount is fed back to perform bonding. After the positions of the head 1 and the substrate support table 2 are corrected, the flip-chip bonding of the semiconductor chip is performed, so that no artificial reading error is accumulated and the quality can be stabilized by improving the bonding accuracy. . In addition, since the inspection can be performed online, the work time required for the inspection is short, and the productivity can be improved. In addition, since the inspection can be performed on-line, it is possible to prevent a sudden failure by performing the periodic inspection, and it is possible to maintain a stable operation operation of the flip chip bonding.
[0028]
Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, the bonding head 1 is not limited to a single unit, and a plurality of bonding heads 1 can operate simultaneously. The number of chips to be suction-held may be not limited to one, but may be plural. Although the camera 6 for mounting position correction and the camera 7 for bonding inspection are imaged by different cameras, they may be performed by the same camera. The inspection chip 9 and the inspection substrate 11 are not limited to glass materials. Other materials such as a plastic material may be used. Further, the substrate support table 2 may be configured to be movable in the θ-axis direction, and the bonding head 1 is configured to be movable in the X-Y direction between the fixed portion of the inspection substrate 11 and the set portion of the mounting substrate. May be. Further, the pattern shapes of the chip-side recognition mark 8 and the substrate-side recognition mark 10 are not limited to those shown in FIG. 4 and may be arbitrary. For example, many modifications may be made without departing from the spirit of the law. .
[0029]
【The invention's effect】
By using the flip-chip mounting apparatus and the flip-chip mounting method according to the present invention, before and after mounting the inspection chip on the inspection substrate, images of both are taken, position data is detected, and the positional deviation amount is fed back to perform bonding. Since the flip-chip bonding of the semiconductor chip is performed after the positions of the head and the substrate support table are corrected, artificial reading errors do not accumulate, and quality can be expected to be stabilized by improving the bonding accuracy. In addition, since the inspection can be performed online, the work time required for the inspection is short, and the productivity can be improved. Further, since the inspection can be performed on-line, it is possible to prevent a sudden failure by performing the periodic inspection, and it is possible to maintain a stable operation operation of the flip chip bonding.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a position shift inspection operation of a flip chip mounting apparatus.
FIG. 2 is an explanatory diagram showing a work for inspecting a position shift of the flip chip mounting apparatus.
FIG. 3 is a block diagram of a control system.
FIG. 4 is an explanatory diagram of a chip-side recognition mark and a board-side recognition mark.
FIG. 5 is an explanatory view showing a work for inspecting a position shift of a conventional flip chip mounting apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Bonding head 2 Substrate support table 3 Table moving mechanism 4 X direction moving stage 5 Y direction moving stage 6 Mounting position correcting camera 7 Bonding inspection camera 8 Chip side recognition mark 9 Inspection chip 10 Board side recognition mark 11 Inspection board 12 Vernier 13 Control unit 14 Operation unit 15 Input / output unit 16 Monitor 17 Motor driver 18 θ-axis motor 19 X-axis motor 20 Y-axis motor

Claims (7)

In a flip chip mounting apparatus for flip chip mounting a semiconductor chip on a substrate,
A vertically movable and rotatable bonding head for sucking and holding the semiconductor chip and bonding the semiconductor chip to a substrate;
A table moving mechanism provided with a substrate supporting table that supports the substrate so as to be movable in XY directions;
First imaging means for moving back and forth between the bonding head and the substrate support table to image the chip surface and the substrate surface and to detect a displacement between the two;
A second image pickup means provided below the substrate support table, for picking up an image of the substrate to which the semiconductor chip is bonded, and detecting a displacement between the two; The inspection chip on which the recognition mark is formed and the inspection substrate on which the board-side identification mark supported by the substrate support table is formed are imaged by the first imaging means, and are obtained from position data obtained by performing image processing. The position of the bonding head and the substrate support table is corrected, the inspection chip is superimposed on the inspection substrate, and the inspection chip and the inspection substrate are imaged by the second imaging means and image processing is performed. The semiconductor chip is mounted on the substrate after correcting the positional deviation of the bonding head and the substrate support table again from the obtained position data. Flip chip mounting apparatus for. The glass chip on which a chip-side recognition mark is formed is used as the inspection chip, and the glass substrate on which a board-side recognition mark is formed is used as the inspection substrate. Flip chip mounting device. For the inspection chip, a glass chip having a chip-side recognition mark whose front and back surfaces are formed in a mirror surface is used, and in the inspection substrate, a glass substrate having a substrate-side recognition mark whose front and back surfaces are formed in a mirror surface is used. 3. The flip chip mounting device according to claim 2, wherein the flip chip mounting device is used. From the chip-side recognition mark and the board-side recognition mark imaged by the first and second image pickup means, image processing is performed to calculate chip and board position data in the X-Y-θ direction. 4. The flip chip mounting apparatus according to claim 1, wherein the position of the bonding head in the θ direction is corrected based on the data, and the position of the substrate support table in the XY direction is corrected. In a flip chip mounting method of flip chip mounting a semiconductor chip on a substrate,
A first imaging step of imaging an inspection chip on which a chip-side identification mark previously held by suction on a bonding head is formed, and an inspection substrate on which a substrate-side identification mark supported on a substrate support table is formed;
A first position correction step of correcting a displacement of the bonding head and the table moving mechanism from position data obtained by performing image processing on image data captured in the first imaging step;
An inspection bonding step of moving the bonding head and overlaying the inspection chip on the inspection substrate;
A second imaging step of imaging the superposed inspection chip and the inspection substrate, and a bonding head and a table from position data obtained by performing image processing on the image data imaged in the second imaging step. Through a second position correction step for correcting the displacement of the moving mechanism,
A substrate mounting step of adsorbing and holding the semiconductor chip on the bonding head and mounting the substrate on a substrate supplied to a substrate support table. The first position correction step is characterized in that the chip-side vernier and the substrate-side vernier are each imaged, the position of the bonding head is corrected in the θ direction, and the position of the substrate support table in the X-Y direction is corrected. The flip-chip mounting method according to claim 5, wherein The second position correction step calculates a position shift in the X-Y-θ direction between the chip-side recognition mark and the substrate-side recognition mark, performs position correction in the θ direction of the bonding head, and The flip-chip mounting method according to claim 5, wherein the position correction in the -Y direction is performed.

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