JPH02249242A - Alignment of chip bonding - Google Patents

Abstract

PURPOSE:To facilitate accurate alignment whether a substrate is transparent or not by a method wherein the image of the substrate is picked up by a substrate detecting camera and the image of a chip is picked up by a chip detecting camera and the two images are synthesized into one image which is displayed by one monitor to align the chip with the substrate. CONSTITUTION:A substrate 1 is placed on a substrate positioning table 20 and a chip 2 is attracted by a bonding tool 23. The image of the substrate 1 on the substrate positioning table 20 is picked up by a substrate detecting camera 21 provided above the substrate positioning table 20 and the image of the chip 2 attracted by the bonding tool 23 is picked up by a chip detecting camera 22 provided away from the substrate positioning table 20. The two images picked up the two cameras 21 and 22 are synthesized into one image which is displayed by one monitor 33 to align the chip 2 with the substrate 1. For instance, the substrate detecting camera 21 is fixed to a point B directly above the reference point A of the substrate positioning table 20 and the chip detecting camera 22 is provided at a point C away from the reference point A by a distance X1 and Y1 so as to be able to rotate and to move along the X and Y directions.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention is a face bonding method in which bumps of a chip are directly stacked on pads or leads (the case of leads will be described below) of a substrate in order to manufacture semiconductor devices. The present invention relates to an alignment method for down-type chip bonding.

[Prior Art] Conventionally, in such chip bonding, the alignment of the leads of the substrate and the bumps of the chip is performed by the method shown in FIG. 5 or 6.

In the method shown in FIG. 5, a chip 2 is held by a bonding tool 3 by suction above a substrate l which is positioned and held in a bonding station (not shown), and a camera 4 disposed below the substrate 1 is used to detect the substrate l. and chip 2 on the same screen, lead 1a of board l and bump 2 of chip 2.
In the figure, 5 indicates a half mirror and 16 indicates a lamp.

In the method shown in FIG. 6, a camera 10 and a half mirror 11 are disposed above the substrate 1, and the light reflected from the substrate 1 by the lamp 12 and the light reflected from the chip 2 by the lamp 13 are transferred to the half mirror.
11 to capture the board 1 and the chip 2 on the same screen of the camera 10, and the leads 1a of the board 1 and the bumps 2a of the chip 2.
Align so that they overlap.

[Problems to be Solved by the Invention] Since the method shown in FIG. 5 projects the chip 2 through the substrate l, it cannot be applied unless the substrate l is transparent.

Since the method shown in FIG. 6 uses reflected light, it can be detected even if the substrate 1 is opaque. However, this method
In order to minimize the number of chips 11 used and simplify the structure, the center of the substrate 1 and the center of the chip 2 should be on a perpendicular line as shown in the figure.
In addition, the substrate 1, the chip 2, and the half mirror 11 must be placed horizontally, and all incident angles and reflection angles must be at the same angle θ1.For this purpose, a table on which the substrate 1 is placed, a bonding tool, etc. 3. The arrangement of the camera 10 and half mirror 11 may be restricted, making installation difficult. Further, there is a drawback that if even one of the angles θ is shifted, a positional shift occurs.

An object of the present invention is to provide a chip bonding alignment method that is applicable regardless of whether the substrate is transparent or opaque, and allows for more accurate alignment.

[Means for Solving the Problems] The above object is to place a board on a board positioning table, adsorb a chip with a bonding tool, and use a board detection camera disposed above the board positioning table to position the board on the board positioning table. The above board is photographed, the chip adsorbed to the bonding tool is photographed using a chip detection camera placed at a location away from the board positioning table, and the two images taken by the two cameras are combined into a circuit. This is accomplished by combining and projecting the images on one monitor and aligning the substrate and chip.

[Effect 1: The board and chip are captured as two images using two cameras installed at separate locations, and the composite circuit is used to combine and display the images on a single monitor. Align at a remote location. Therefore, it can be applied regardless of whether the substrate is transparent or opaque, and alignment can be performed easily and accurately. Furthermore, the camera can be installed at any position, and the angle of the camera can be easily set, making it difficult for positional deviation to occur.

[Example] An example of the present invention will be described below with reference to FIGS. 1 to 4. As shown in FIG. 1, a substrate detection camera 21 that detects the substrate l placed on the substrate positioning table 20 and a chip detection camera 22 that detects the chip 2 held by the bonding tool 23 are arranged. It is set up. The substrate detection camera 21 is fixed at a point B on the substrate positioning table 20 directly above the reference point A (for example, the bonding position).

The chip detection camera 22 is rotatable and movable in the XY force directions, and is disposed at a zero point away from the reference point A. The bonding tool 23 is provided so as to be movable and rotatable in the vertical (Z) and XY force directions, and can be positioned at point D directly above point 0 and point E directly above point A. Further, a substrate feeder 24 is provided before and after the substrate positioning table 20 for feeding and feeding the substrate l to the substrate positioning table 20.

The two cameras 21 and 22, as shown in FIG.
The timing circuit 30 inputs rise and fall time signals set to the deflection circuit 31, and the camera 21
．． 22 converts the video beam into a signal, and a synthesis circuit 32 synthesizes and amplifies the signals from the two cameras 21 and 22.
The composite image is displayed by inputting it to a monitor 33.

Next, the method of the present invention will be explained. First, as shown in FIG. 3, a jig 43 stores two transparent plates 41 and 42 with a mark 40 or an alternative thereon on the point A of the substrate positioning table 20 with the marks 40 aligned. to be fixed. This is photographed by the substrate detection camera 21. Naturally, in this state, the marks 40 on the two transparent plates 41 and 42 overlap and are transferred to the monitor 33 (see FIG. 2).

Next, the bonding tool 23 is moved in the XY force direction using an electric manipulator to position it at point E directly above point A. Subsequently, the bonding tool 23 is lowered to attract the uppermost transparent plate 41, and again rises or rises to point E, and then moves in the XY force direction to position it at point D. The bonding tool 2 stores the xY force direction distances xt and yt of the bonding tool 23 at this time in a computer or the like.
3 is located at point D, the chip detection camera 22 photographs the transparent plate 41 that is adsorbed to the bonding tool 23, and the remaining transparent plate 4z photographed by the board detection camera 21 and the chip detection camera 22. The two images of the transparent plate 41 shown in the image are made into a composite image through the combining circuit 32 shown in FIG.
．． The position and magnification of the chip detection camera 22 are adjusted so that the alignment marks 40 of 42 coincide with each other. The position and magnification of the substrate detection camera 21 are set before the bonding tool 23 adsorbs the transparent plate 41.

This completes the adjustment of the magnification and position of the two cameras. Therefore, the transparent plates 41 and 42 and the jig 43 are removed.

Next, as shown in FIG. 1, the substrate 1, which is an actual sample, is positioned and placed on point A of the substrate positioning table 20, the chip 2 is attracted to the bonding tool 3, and the substrate detection camera 2
1 at point B and the bonding tool 23 at point D, respectively. Then, when the board 1 is photographed by the board detection camera 21 and the chip 2 is photographed by the chip detection camera 22, a composite image is displayed on the monitor 33 through the composition circuit 32 shown in FIG. 2 as shown in FIG. 4(a). 0 projected as
Next, the chip 2, that is, the bonding tool 23 is rotated and moved in the XY force direction, or the substrate positioning table 20 is rotated and moved in the XY force direction, so that the substrate
Align the leads Ia and the bumps 2a of the chip 2. Various methods can be considered for this positioning method, which will be described later.

Next, the bonding tool 23 is moved the distance Xl, Yl determined in the explanation of FIG. When attached, the bumps 2a of the chip 2 are superimposed on the leads la of the substrate l, and are bonded accurately.

Thereafter, the operations described in FIG. 1 are performed manually or automatically, and bonding is performed automatically in sequence.

Next, two methods for aligning the substrate 1 and the chip 2 from the state shown in FIG. 4(a) as shown in FIG. 4(C) will be described.

In Fig. 4 Ca'), x and y indicated by solid lines are reference cross lines, The reference lines are respectively shown, and θ' is the inclination of the reference lines x', y' from the reference lines x, y, that is, the inclination angle of the substrate 1, θ'
°° indicates the inclination of the reference lines X", y" from the reference lines x, y, that is, the inclination angle of the chip 2, respectively;
0゛, θ°°, and chip 2 or substrate 1 as θ=θ゛'
When rotated by -θ°, substrate 1 and chip 2 become parallel as shown in Figure (b) (the figure shows the state in which substrate l has been rotated). When the chip 2 is moved by Δy (parallel movement), the point a of the chip 2 aligns with the point b of the lead 1a, and the lead la and the bump 2a overlap as shown in FIG. 2C. In reality, it moves simultaneously in the θ direction and the xY force direction.

The state shown in FIG. 4(a) changes to the state shown in FIG. 4(C) all at once.

Another method is to use the tip 2 as shown in Figure 4(a).
any two points a1, a2 on the substrate 1, and any two points b1 on the substrate 1,
b2 is determined in advance. First, the inclination angle α of the chip 2 is determined. The deviation in the xy direction of the reference line of the predetermined a, a2 is Δx1, - Δy2. If the inclination angle β of the substrate l is determined, β=j anτ. Therefore, the deviation angle θ between the substrate l and the chip 2 is θ =α−
It is determined by β. Here, θ〉0 is clockwise as seen from the figure, θ
0 means counterclockwise rotation as seen from the diagram. Therefore, the substrate l is θ
When rotated, the substrate 1 and the chip 2 become parallel as shown in the same figure (b).The deviation ΔX, Δy between the predetermined point al of the chip 2 and the point S of the substrate 1, which are predetermined in the 0th order, is detected. However, when the chip 2 is moved by Δx in the X-axis direction and Δy in the y-axis direction, the leads 1a and the bumps 2a overlap as shown in FIG. In this way, any arbitrary two
By determining points and determining which points correspond to which points, automatic detection and automatic bonding can be performed.

Note that the two cameras 21 and 22 explained in FIG.
It is only necessary to adjust the magnification and position once at the beginning, and it is not necessary during subsequent alignment and bonding.
Although a cross mark 40 is attached to the mark, the present invention is not limited to this, and triangle, square, or circle marks may also be attached.
Alternatively, the marks 40 may not be attached, and the transparent plates 41 and 42 may have the same size so that their outer shapes match. Although the position in the XY force direction was calculated when the board was moved upward, the position of the board positioning table 20 was already
It goes without saying that when the distance from the position to above the chip detection camera 22 is known in advance, there is no need to calculate this distance anew.

[Effects of the Invention] As is clear from the above explanation, according to the chip bonding alignment method of the present invention, two cameras installed correspondingly to the substrate and the chip can be used at separate locations. Since the two images are taken out and combined on one monitor using a compositing circuit, and the board and chip are aligned at a separate location, it can be applied regardless of whether the board is transparent or opaque, and alignment is easy. Can be performed quickly and accurately. Also, the camera can be installed in any position,
Furthermore, the angle of the camera can be easily set, and positional deviations that occur in the prior art are less likely to occur.

[Brief explanation of drawings]

Fig. 1 shows an embodiment of the present invention, (a) is a front view, (b) is a perspective view, Fig. 2 is a circuit diagram, and Fig. 3 is a method for adjusting the magnification of the camera. ) is a front explanatory view, (b)
4(a), 4(b), and 4(c) are illustrations showing the position adjustment of the substrate 1 and chip 2 projected on the monitor, and FIG. 5 is a conventional method in the case of a transparent substrate. FIG. 6 is an explanatory diagram showing a conventional method in the case of an opaque substrate. 1: Board, 2: Chip, 20: Board positioning stand,
21: Board detection camera, 22: Chip detection camera, 23: Bonding tool, 32
: synthesis circuit, 33: monitor, 40: mark,
41.42: Transparent plate. (G) 22: Chip detection camera 23: Bonding tool (a) Figure 2: Chip zO: Board positioning 21: Board detection camera 22: Chip detection camera 23: Bonding tool Figure (b) 20: Board Positioning table 2L: Board detection camera 22: Chip detection camera 23: Bonding tool 40: Marks 41.42: Transparent plate

Claims (2)

[Claims] (1) Place the board on the board positioning table, adsorb the chip with a bonding tool, photograph the board on the board positioning table with a board detection camera disposed above the board positioning table, and take a picture of the board on the board positioning table. A chip detection camera placed far away from the bonding tool captures the chip adsorbed to the bonding tool, and the two cameras take out the chip.
A chip bonding alignment method characterized in that two images are synthesized and displayed on one monitor using a synthesis circuit, and a substrate and a chip are aligned. (2) Place one of the two transparent plates with marks or of the same size on the substrate positioning table, attach the other to the bonding tool, and use the board detection camera installed above the substrate positioning table to The transparent plate on the substrate positioning table was photographed, the transparent plate adsorbed to the bonding tool was photographed using a chip detection camera placed at a location away from the substrate positioning table, and the two cameras taken out by the two cameras were photographed. The images are synthesized and displayed on one monitor using a synthesis circuit, and
Adjust the magnification and position of the camera on the stand, then place the board on the board positioning stand, adsorb the chip to the bonding tool, take out the board and chip as two images with the two cameras, and combine the A chip bonding alignment method characterized in that the substrate and the chip are aligned by combining and projecting the images on the one monitor using a circuit.