JP2746808B2 - Wire bonding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of first bonding portions such as electrode pads of a semiconductor chip fixed to a lead frame or a substrate, and a plurality of first bonding portions of each lead terminal of the lead frame or a wiring pattern of a substrate. The present invention relates to a method of performing wire bonding between a plurality of second bonding portions with a thin metal wire.

[0002]

2. Description of the Related Art Conventionally, in this type of wire bonding, as described in, for example, Japanese Patent Application Laid-Open No. 55-107240, a ball is formed at the tip of a metal wire inserted through a capillary tool. The ball is pressed and joined to the first bonding portion by the downward movement of the capillary tool. Next, the capillary tool is moved to the position of the second bonding portion, the metal wire is bent in the direction of the second bonding portion, and then descends, thereby pressing and joining the metal wire to the second bonding portion. . Then, after raising the capillary tool while cutting the metal wire, the next first bonding portion is moved to form a ball at the tip of the metal wire, thereby completing one cycle of wire bonding,
A method is employed in which wire bonding in this cycle is repeatedly performed between the next first bonding portion and the second bonding portion.

[0003]

However, in the conventional wire bonding method, the one-cycle wire bonding is repeatedly performed for each of a large number of bonding portions, while the one-cycle wire bonding is required. Since the time includes the time required to bend the metal wire and the time required to press-bond the metal wire to the second bonding portion, wire bonding is performed to all the bonding portions. The time required for this is a value obtained by multiplying the time required for one cycle of wire bonding by the number of electrode pads, and a long time is required.
As a result, there is a problem that the cost is significantly increased.

An object of the present invention is to provide a method capable of reducing the time required for wire bonding to a large number of bonding portions.

[0005]

SUMMARY OF THE INVENTION In order to achieve this technical object, the present invention relates to a method in which a ball at the tip of a metal wire inserted into a capillary tool is moved downward for a plurality of first bonding portions. And pressing the capillary tool up and then fusing the middle of the metal wire and simultaneously forming balls at both ends of each of the first bonding portions. Then, a metal wire piece having a ball at the tip is erected, and then the metal wire pieces are bent toward a plurality of second bonding portions by a plurality of metal wire pieces, respectively. The ball at the tip of
Press bonding is simultaneously performed on the second bonding portions corresponding to the respective metal wire pieces.

[0006]

In this manner, a plurality of metal wire pieces erected on each of the first bonding portions are bent in the direction of the second bonding portion, and the ball at each of the ends is moved to the second bonding portion. By simultaneously pressing and bonding to each of the bonding portions, the metal wire piece bonded to the first bonding portion is bent in the direction of the second bonding portion, and
Since a plurality of balls can be simultaneously pressed and bonded to the second bonding portion at the tip of the metal wire piece, the ball is bent in the direction of the second bonding portion, and the ball is bonded to the second bonding portion. The time required for pressure bonding, as in the conventional case, bending the metal wire bonded to the first bonding portion in the direction of the second bonding portion, and pressing and bonding to the second bonding portion, Compared to the case of performing the bonding one by one, the bending of the metal wire pieces and the bonding to the second bonding portion can be significantly reduced by the amount of performing a plurality of pieces simultaneously.

[0007]

Therefore, according to the present invention, a large number of first
Since the time required for wire bonding between the bonding portion and the same number of second bonding portions can be considerably reduced, there is an effect that the cost of wire bonding can be surely reduced.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a lead frame. The lead frame 1 has a substantially rectangular tab 2 and a large number of lead terminals 3 (second bonding portions) extending toward four sides of the tab 2. And Reference numeral 4 denotes a substantially rectangular semiconductor chip fixed to the upper surface of the tab 2 of the lead frame 1. On the upper surface of the semiconductor chip 4, a large number of electrode pads 5 (first bonding portions) are provided. 4 are formed at appropriate intervals along the four sides.

In FIG. 2, reference numeral 6 denotes a capillary tool disposed above the semiconductor chip 4, and a ball 8 a at the tip of a metal wire 7 inserted into the capillary tool 6 is moved by the downward movement of the capillary tool 6. As shown in FIG. 3, the semiconductor chip 4 is pressed and joined to one electrode pad 5, and then the capillary tool 6 is moved upward. As described above, by blowing the hydrogen gas combustion torch ejected from the nozzle 9, the metal wire piece 7 ′ joined to the one electrode pad 5 from the metal wire 7 is blown, and at the same time, both ends of the blow, that is, ,
By forming balls 8a and 8b at the tip of the metal wire 7 and the tip of the metal wire piece 7 ', the ball 8b was formed at the tip of the one electrode pad 5 as shown in FIG. The metal wire pieces 7 'are joined and erected.

[0010] Then, by performing this for each of the electrode pads 5 on the semiconductor chip 4, as shown in FIG.
The metal wire pieces 7 'formed with b are joined and erected. In FIG. 6, reference numeral 10 denotes an arm 10a configured to move in two directions: an X-axis direction and a Y-axis direction perpendicular thereto.
A vertical axis 10c provided at the tip of the arm 10a so as to rotate forward and backward by transmission of a belt 10b from a motor (not shown), and a bending rod 10d projecting laterally from the vertical axis 10c. The bending mechanism
The bending rod 10d in the bending mechanism 10 is set on the vertical axis 10c.
By appropriately performing a moving operation by rotation and movement of the arm 10a in the two directions, each of the metal wire pieces 7 'is bent while being distributed in the direction of the lead terminal 3 by a plurality of pieces.
As shown in FIG. 7, the ball 8b at the tip of each metal wire piece 7 'is connected to the lead terminal 3 corresponding to each metal wire piece 7'.
Contact against

Next, as shown in FIGS. 7 and 9, the ball 8b at the tip of each of the bent metal wire pieces 7 'is pressed into a plurality of balls 8b by a pressing member 11 as shown in FIGS. The members are pressed together and joined to the lead terminals 3. That is, a plurality of metal wire pieces 7 'erected on each of the electrode pads 5 in the semiconductor chip 4 are bent in the direction of the lead terminals 3 by a plurality of bending rods 10d, and the balls 8b at the respective tips are bent. Since each of the lead terminals 3 is simultaneously pressed and joined by the press member 11, the metal wire pieces 7 'joined to each of the electrode pads 5 are bent in the direction of each of the lead terminals 3. And ball 8b at the tip of each metal wire piece 7 '
Can be simultaneously bonded to the lead terminal 3 by a plurality of pieces, and each metal wire piece 7 'can be bent in the direction of the lead terminal 3;
Therefore, the time required for pressure bonding can be greatly reduced by the number of times that these are simultaneously performed.

In this case, the first step of connecting and setting up the metal wire pieces 7 'to the respective electrode pads 5 of the semiconductor chip 4 and the bending of the metal wire pieces 7' and the pressure bonding to the lead terminals are performed. By performing the second step to be performed in another stage, the first step and the second step can be performed in an overlapping manner, so that the time required for all wire bonding can be further reduced. You can do it.

The bending of the metal wire pieces 7 'and the pressure bonding to the lead terminals 3 may be performed simultaneously for all the metal wire pieces 7'. In the embodiment, wire bonding is performed between each of the electrode pads 5 of the semiconductor chip 4 fixed to the lead frame 1 and each of the lead terminals 3 of the lead frame 1, but the present invention is not limited to this. The present invention is not limited to this, and it is needless to say that the present invention can be applied to a case where wire bonding is performed between a semiconductor chip fixed to a substrate and a wiring pattern on the substrate.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state where a semiconductor chip is fixed to a lead frame.

FIG. 2 is a perspective view showing a state where a metal wire is bonded to the semiconductor chip.

FIG. 3 is an enlarged sectional view taken along the line II-II of FIG.

FIG. 4 is a diagram showing a state in which a metal wire is blown.

FIG. 5 is a perspective view of a state in which a metal wire piece is erected on the semiconductor chip.

FIG. 6 is a perspective view showing a state in which a large number of metal wire pieces are erected on the semiconductor chip.

FIG. 7 is a perspective view showing a state in which each of the metal wire pieces is bent in the direction of a lead terminal.

FIG. 8 is an enlarged sectional view taken along line VIII-VIII of FIG. 7;

FIG. 9 is a diagram showing a state in which the tip of the metal wire piece is pressed and joined to a lead terminal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead frame 2 Tab 3 Lead terminal 4 Semiconductor chip 5 Electrode pad 6 Capillary tool 7 Metal wire piece 8a, 8b Ball 10 Bending mechanism 10d Bending rod 11 Press member

Claims (1)

(57) [Claims] 1. A method according to claim 1, wherein:
The ball at the tip of the metal wire inserted into the capillary tool is pressed and joined by descending the capillary tool, and after raising the capillary tool, fusing the middle of the metal wire and simultaneously forming balls at both ends thereof, By performing the process for each one bonding portion, a metal wire piece having a ball at the tip is erected on each of the first bonding portions, and then a plurality of the second metal wire pieces are provided. After bending toward the bonding portion, the balls at the tips of the plurality of metal wire pieces are simultaneously pressed and bonded to the second bonding portions corresponding to each of the metal wire pieces. Wire bonding method.