JPH06310569A - Face-down bonding method of semiconductor element - Google Patents

Abstract

PURPOSE:To bond a semiconductor element and a circuit board at the correct position by recognizing reference patterns with an image pickup camera, and controlling the position of a chuck part of a chip mounter so as to align the position with a through hole. CONSTITUTION:A pattern surface 10a of a semiconductor element 10 held with a flat collet 20 of a chip mounted, is brought close to a circuit board 1. A cross mark 30a and the cross mark on the chip mounter are recognized with an image pickup camera 22, respectively, from the lower side of a through hole 1a. The position of the flat collet 20 is controlled so that the positions of the cross mark 30a and the through holes 1a are aligned based on the image information obtained by processing the image of each output. Under the state wherein the position alignment is completed, the semiconductor element 10 is lowered to the side of the circuit board 1. Each bump 11 is brought into contact with each corresponding connecting terminal 5. Bonding is performed by thermocompression binding. The face-down bonding method, by which the mounting accuracy can be improved and which is suitable for the small-amount production for many kinds of articles, can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a face-down bonding method for a semiconductor element by a COB (Chip on Board) method, which is a kind of wireless bonding method for directly bonding a semiconductor element to a circuit board.

[0002]

2. Description of the Related Art Conventionally, as a face-down bonding method for such a semiconductor element, as shown in FIGS. 7 (a) and 7 (b), a semiconductor mount pattern surface 70a is directed to a circuit board side and a chip mounter is used. The chuck 71 holds the semiconductor element 70, and each bump 70 formed on each electrode portion on the semiconductor element pattern surface 70a, for example, each electrode pad.
A method is known in which b is joined to each connection terminal of the wiring pattern in the semiconductor element mounting portion on the circuit board, and the electrode of the semiconductor element 70 and the wiring pattern of the circuit board are connected via the bump 70b.

[0003]

However, in the above-mentioned conventional technique, since the semiconductor element 70 is mounted on the circuit board with the semiconductor element pattern surface 70a facing downward, the position of the semiconductor element 70 with respect to the circuit board is confirmed, that is, the semiconductor element 70 is mounted. It is difficult to confirm the position of each electrode portion (each bump 70b) of the semiconductor element 70 with each connection terminal of the circuit board, and each electrode portion of the semiconductor element 70 is correctly positioned at each connection terminal of the circuit board. There was a problem that it was difficult to join with.

Further, in the above-mentioned conventional technique, the semiconductor element 70 is used.
In order to improve the mounting accuracy of the chip mounter, a pyramid collet is used as the chuck portion 71 of the chip mounter.
The semiconductor element 70 is positioned with respect to the chip mounter such that the center of the semiconductor element 70 is aligned with the axis of the pyramid collet 71 and the semiconductor element pattern surface 70a is horizontal, and then the semiconductor element 70 is vacuum chucked with the pyramid collet 71 to form a circuit. A predetermined amount is conveyed to the substrate side. However, in this case, the semiconductor element may move and tilt during the transportation of the semiconductor element, and even if the semiconductor element held by the pyramid collet 71 is accurately transported by a predetermined amount, each electrode portion of the semiconductor element is transported. Is difficult to join to each connection terminal of the circuit board at the correct position, and the pyramid collet needs to be made according to the size of each semiconductor element. There was a problem that was not suitable for.

The present invention aims to improve the mounting accuracy and to provide a face-down bonding method suitable for small-quantity multi-product production by sharing the chuck part by using an inexpensive flat collet as the chuck part. It is an object.

[0006]

In order to achieve the above object, the present invention is directed to a semiconductor element pattern surface on the semiconductor element pattern surface, with the semiconductor element pattern surface facing the circuit board side and holding the semiconductor element by the chuck portion of the chip mounter. In the face-down bonding method of the semiconductor element in which each electrode part of is bonded to each connection terminal of the wiring pattern in the semiconductor element mounting part on the circuit board, the circuit board is provided with a through hole serving as a positioning reference for each connection terminal. A step of providing, a step of providing a reference pattern on the semiconductor element pattern surface, which serves as a positioning reference for each of the electrode portions, and a step of providing the semiconductor element pattern surface in the vicinity of the circuit board, on the semiconductor element pattern surface. A step of recognizing the reference pattern from below the through hole with an imaging camera, and an image processing of the output of the imaging camera. A step of controlling the position of the chuck portion so that the reference pattern is aligned with the through hole based on image information obtained as a result, and the semiconductor element is moved to the circuit board side in a state where the alignment is completed. The process consists of pushing down.

[0007]

The image information obtained by recognizing the reference pattern on the semiconductor element pattern surface from below the through hole by the image pickup camera and processing the output of the image pickup camera with the semiconductor element pattern surface being close to the circuit board. Based on the above, the position of the chuck part of the chip mounter is controlled so that the reference pattern is aligned with the through hole, and when this alignment is completed, the semiconductor element is pushed down to the circuit board side, Since each of the electrode portions is bonded to each connection terminal of the wiring pattern in the semiconductor element mounting portion on the circuit board, each electrode portion of the semiconductor element is bonded to each connection terminal of the circuit board at the correct position.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A face-down bonding method for a semiconductor device according to an embodiment of the present invention will be described below with reference to the drawings. In this specification, the face-down bonding method is a wireless bonding method in which a semiconductor element is directly bonded to a circuit board by a COB (Chip on Board) method.

FIG. 2 shows a circuit board used in a face-down bonding method for a semiconductor device according to an embodiment of the present invention. As shown in FIGS. 2 and 3, the circuit board 1
The wiring pattern 2 is formed on the. A part of the wiring pattern 2 is covered with a solder resist 3 formed by printing. Further, in the semiconductor element mounting portion 4 of the circuit board 1, a plurality of wiring patterns 2 (in this embodiment, 1
1) of the connection terminals 5 is exposed to the outside.

On the other hand, in the semiconductor element 10 bonded to the circuit board 1, as shown in FIGS. 1A and 4, electrode patterns (not shown) on the pattern surface (semiconductor element pattern surface) 10a are formed. As with the wiring pattern 2, a plurality of bumps 11 (the same number as the connection terminals 5) made of gold are formed. Each bump 11 is formed at a position corresponding to the end of each connection terminal 5.

In order to carry out the face-down bonding method of the semiconductor device according to the embodiment of the present invention, as shown in FIG. 4, a flat collet (chuck portion) 20 for holding the semiconductor device 10 by vacuum chucking. And a chip mounter 21 for carrying the semiconductor element 10 held by the flat collet 20 and two image pickup cameras 22 and 23.
And an image processing device 24 for image-processing each output from both imaging cameras 22 and 23 and outputting an image information signal, and an XY table of the chip mounter 21 on which the flat collet 20 is mounted or a flat collet 20. The driving device 25 for driving the robot arm of the chip mounter 21 and the driving device 25 based on the image information signal from the image processing device 24.
And a control unit (CPU) 26 for controlling the.

A face-down bonding method for a semiconductor device according to an embodiment of the present invention is described in the following steps (1) to (1).
It has (6).

(1) The circuit board 1 is provided with circular through holes 1a and 1b serving as a positioning reference for each connection terminal 5 (see FIGS. 2 and 4). The through hole 1a is provided in the central portion of the semiconductor mounting portion 4. On the other hand, the through hole 1b may be separated from the through hole 1a by an arbitrary distance.

(2) Pattern surface 1 of the semiconductor element 10
0a is a reference pattern serving as a positioning reference for each of the bumps 11, and a cross mark 30a that is positioned with the through hole 1a is provided, and on the surface 21a of the chip mounter 21 facing the circuit board 1, A reference pattern serving as a positioning reference for the bump 11,
A cross mark 30b that is positioned with the through hole 1b is provided (see FIGS. 4 and 5).

(3) Pattern surface 10a of the semiconductor element 10
So that the semiconductor element 10 is flat and the flat collet 20
And vacuum chuck to convey it above the circuit board 1 (see FIG. 1).
(See (a)).

(4) Pattern surface 10a of the semiconductor element 10
The circuit board 1 close to the circuit board 1 (the state of FIG. 1A)
To form the cross mark 30a on the pattern surface 10a and the cross mark 30b on the chip mounter 21 in the through holes 1a, 1
It is recognized by the imaging cameras 22 and 23 from below b (see FIG. 1A and FIG. 4).

(5) Based on the image information obtained by image-processing the outputs of both imaging cameras 22 and 23, the cross mark 3
The position of the flat collet 20 is controlled so that 0a and 30b are aligned with the through holes 1a and 1b. That is, the outputs of both imaging cameras 22 and 23 are image-processed by the image processing device 24, and the control unit 26 determines the centers of the through holes 1a and 1b and the respective images based on the image information signal output from the image processing device 24. The displacement amount from the center of the cross marks 30a and 30b is calculated and a control signal corresponding to the displacement amount is output to the driving device 25, and the XY table of the chip mounter 21 on which the flat collet 20 is mounted is driven by the driving device 25. Alternatively, the robot arm of the chip mounter 21 holding the flat collet 20 is driven. As a result, each cross mark 30
The position of the flat collet 20 is feedback-controlled so that the centers of a and 30b coincide with the centers of the through holes 1a and 1b.

(6) With the above alignment completed,
That is, as shown in FIG. 5 and FIG.
With the centers of a and 30b aligned with the centers of the through holes 1a and 1b, the semiconductor element 10 at the position shown in FIG.
With each corresponding connection terminal 5 (see FIG. 1B).

(7) The semiconductor element 10 is further pushed down to the circuit board 1 side so that each bump 11 is crushed by a certain amount in a state of contacting each corresponding connection terminal 5 (state of FIG. 1B).

(8) Each bump 11 is bonded to each connection terminal 5 by thermocompression bonding (see FIG. 6).

(9) The dispenser 40 positioned above the semiconductor element 10 and the dispenser 4 inserted into the through hole 1a with each bump 11 bonded to each connection terminal 5.
By discharging a sealing agent such as epoxy resin from 1 and 2, the entire periphery of the semiconductor element 10 is sealed with the sealing agent from both upper and lower sides of the semiconductor element 10 to protect the semiconductor element 10 (FIG. 1C). And (d)). The outline of the covering by this sealant is shown by a chain line A in FIG.

According to this embodiment, the cross mark 30a on the pattern surface 10a and the cross mark 30b on the chip mounter 21 are recognized by the image pickup cameras 22 and 23 from below the through holes 1a and 1b, respectively (see the above step (4 )), Based on the image information obtained by performing image processing on the outputs of both imaging cameras 22 and 23, the flat collet 20 is arranged so that the centers of the cross marks 30a and 30b coincide with the centers of the through holes 1a and 1b. Is feedback-controlled (step (5) above) to complete the alignment, that is, in FIG.
Also, as shown in FIG. 6, with the center of each cross mark 30a, 30b aligned with the center of each through hole 1a, 1b, the semiconductor element 10 is pushed down to the circuit board 1 side and each bump 11 is pressed.
To contact each corresponding connection terminal 5 (see the above step (6)), and thereafter each bump 11 on the pattern surface 10a is bonded to each connection terminal 5, so that each bump (electrode portion) of the semiconductor element 10 Are bonded to the respective connection terminals 5 of the circuit board 1 at correct positions (see FIG. 6).

In this embodiment, as a through hole serving as a positioning reference for each connection terminal 5, a circular through hole 1a is provided at the center of the semiconductor element mounting portion 4 and also at a portion other than the mounting portion 4. Although the circular through hole 1b is provided, the present invention is not limited to this. For example, as another embodiment, a configuration in which a deformed through hole such as a long hole shape is provided only in the central portion of the mounting portion 4 is conceivable. In this case,
The cross mark 30b provided on the surface 21a of the chip mounter 21 is unnecessary.

[0024]

As described in detail above, according to the present invention,
With the semiconductor element pattern surface close to the circuit board,
The chip mounter is used so that the reference pattern on the semiconductor element pattern surface is recognized by the imaging camera from below the through hole, and the reference pattern is aligned with the through hole based on the image information obtained by image processing the output of the imaging camera. By controlling the position of the chuck part of the device and pushing down the semiconductor element to the circuit board side when this alignment is completed, each electrode part on the semiconductor element pattern surface is placed in the wiring pattern on the semiconductor element mounting part on the circuit board. Since each of the electrode terminals of the semiconductor element is joined to each of the connecting terminals of the circuit board at the correct position. Therefore, it is possible to improve the mounting accuracy, and by using an inexpensive flat collet as a chuck portion for holding a semiconductor element, the chuck portion can be shared, and a face-down bonding method suitable for small-quantity multi-product production. Can be obtained.

[Brief description of drawings]

1A to 1D are explanatory views of a face-down bonding method for a semiconductor device according to an embodiment of the present invention, and FIG. 1A is a diagram showing a state in which the semiconductor device is brought close to a circuit board. FIG. 7A is a diagram in which each bump of the semiconductor element is joined to each connection terminal of the circuit board. FIG. 9C is a cross-sectional view showing a state in which the entire periphery of the semiconductor element is sealed from the upper and lower surfaces with a sealant. FIG. 4 is a cross-sectional view showing a state in which the entire semiconductor element is sealed with a sealant.

FIG. 2 is a plan view showing a circuit board used in a face-down bonding method for a semiconductor device according to the present invention.

FIG. 3 is a partially enlarged view of FIG.

FIG. 4 is a schematic configuration diagram showing an apparatus for carrying out a face-down bonding method for a semiconductor device according to the present invention.

FIG. 5 is a plan view of the circuit board seen from below, which is an explanatory diagram for explaining the alignment of the semiconductor element and the circuit board.

FIG. 6 is a plan view showing a state in which each bump of the semiconductor element is bonded to each connection terminal of the circuit board at a correct position.

FIG. 7A is a view showing a conventional example, and is a cross-sectional view showing a state in which a semiconductor element is vacuum chucked by a chuck portion;
FIG. 7B is a plan view of FIG. 7A viewed from below.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit board 1a, 1b Through hole 2 Wiring pattern 4 Semiconductor element mounting part 5 Connection terminal 10 Semiconductor element 10a Pattern surface (semiconductor element pattern surface) 20 Flat collet (chuck part) 21 Chip mounter 22 Imaging camera

Claims (1)

[Claims] 1. A semiconductor element is held by a chuck portion of a chip mounter with the semiconductor element pattern surface facing the circuit board side, and each electrode portion on the semiconductor element pattern surface is provided in a semiconductor element mounting portion on the circuit board. In a face-down bonding method of a semiconductor element to be bonded to each connection terminal of a pattern, a step of providing a through hole which serves as a positioning reference for each connection terminal in the circuit board, and each electrode part on the semiconductor element pattern surface. A step of providing a reference pattern serving as a positioning reference for the semiconductor element pattern surface in a state where the semiconductor element pattern surface is brought close to the circuit board, and the reference pattern on the semiconductor element pattern surface is recognized from below the through hole by an imaging camera. And a reference pattern based on image information obtained by image-processing the output of the imaging camera. A semiconductor device comprising: a step of controlling the position of the chuck part so as to be aligned with the through hole; and a step of pushing down the semiconductor element to the circuit board side in a state where the alignment is completed. Face down bonding method.