JPH0124931Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire bonding device used in the assembly process of semiconductor devices.

Wire bonding equipment operates at high speed,
In addition, it is required to be able to easily respond to changes in the type of semiconductor devices, but in order to meet these demands, it is advantageous to directly drive the capillary with a DC motor, rather than the conventional method of driving the capillary with a cam. . However, in this method, when the capillary comes into contact with the electrode of the semiconductor pellet, a large pressure is temporarily applied to the electrode, which may adversely affect the bonding quality. In other words, if this control method is used that simply detects that the speed of the capillary becomes zero and then switches to pressure control, the capillary that is under speed control will be temporarily stopped, causing excessive stress on the DC motor. Drive current flows. This causes drawbacks such as cracks in the semiconductor pellet and excessive crushing of the gold wire.

The present invention eliminates the above-mentioned drawbacks, operates at high speed,
To provide a wire bonding device that can easily cope with the exchange of types of semiconductor devices and has high bonding quality.

In the present invention, in a wire bonding device in which a capillary is driven by a DC motor, after the capillary approaches a predetermined distance from an electrode until bonding is completed, a constant speed command is given to the DC motor, and a current flows through the DC motor. By limiting the value to a predetermined value corresponding to the bonding pressure, it is possible to prevent excessive pressure from being applied to the electrode when the capillary comes into contact with the electrode, thereby realizing a wire bonding device with high bonding quality.

This will be explained below using the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the present invention.
FIG. 2 is an explanatory diagram illustrating the operation of the capillary. In FIG. 1, 1 is a semiconductor pellet, and 2 is an external electrode. A capillary 4 is attached to the tip of an arm 5 directly connected to the shaft of a DC motor 6, and a gold wire 3 is connected to the electrode of the semiconductor pellet 1 and the external electrode 2. 4. Electrical connection is made by thermocompression bonding. Position detector 7 and speed detector 8 are DC motor 6
are attached to the shafts of the capillary 3 and detect the position and speed of the capillary 3, respectively. The speed command circuit 12 outputs a speed command value to the speed control circuit 13 while referring to the position signal from the position detector 7. The speed control circuit 13 compares the speed command value from the speed command circuit 12 and the speed signal from the speed detector 8, and supplies a current proportional to the difference to the DC motor 6 via the current limiting circuit 15.
flow to. The current limiting circuit 15 limits the drive current of the DC motor 6 to a set value or less.

Next, the operation of this embodiment will be explained according to the movement of the capillary shown in FIG. Between points a and b in FIG. 2, the current limiting circuit 15 is set to a sufficiently large current limiting value, and the speed of the DC motor 6, and therefore the speed of the capillary 3, follows the command value from the speed command circuit 12. Under profile control, the capillary 3 moves at high speed from the pellet electrode to a point b at a predetermined height. After reaching point b, the speed command circuit 12 outputs a low constant speed command value, and the current limit circuit 15 outputs a constant current limit value determined by the bonding pressure, the torque constant of the motor 6, and the length of the arm 5. Set. When the capillary 3 descends at a constant speed from point b and touches the pellet electrode at point c, the capillary is stopped and the speed control circuit 13 attempts to flow a current corresponding to the speed command value to the DC motor 6, but the current limit circuit 15 As a result, a current of an upper limit value set by the current limiting circuit 15 flows through the DC motor 6, and the capillary 3 generates a predetermined bonding pressure. At the same time, it is detected that the speed has become zero at point c, and the capillary 3 continues to be pressurized for a predetermined bonding time. When the bonding time ends at point d, the capillary rises to point e under the same control as from point a to point b, and then rises to point f.
descend to. During this time, capillary 3 is connected to arm 5,
It is moved to the top of the external electrode by an XY table (not shown) together with a drive system such as the motor 6. The points from point f to point g, and from point g to point h are the points b and c mentioned above.
After performing the same operation as between points d, it moves up to point i by performing the same operation as between points a and b, and is positioned at point i by a positioning circuit (not shown).

In the present invention, since the above-mentioned operation is performed, the current flowing through the DC motor 6 is limited in advance to prevent the generation of pressure greater than the bonding pressure at the points c and g where the capillary contacts the electrode, thereby causing cracks in the semiconductor pellet. High-quality bonding can be performed without crushing the gold wire too much.

As explained above, in the wire bonding device of the present invention, the capillary is directly driven by a DC motor, achieving high-speed operation and high flexibility for changing conditions. Since the amount of bonding is limited, high-quality bonding can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the operation of a capillary in a wire bonding apparatus. 1... Semiconductor pellet, 2... External electrode, 3...
...Gold wire, 4...Capillary, 5...Arm, 6...
...DC motor, 7... Position detector, 8... Speed detector, 12... Speed command circuit, 13... Speed control circuit, 15... Current limiting circuit.

Claims (1)

[Scope of utility model registration request] A DC motor that drives a capillary, means for detecting the position and moving speed of the capillary, a speed command circuit that generates a moving speed command for the capillary, and a difference between the moving speed of the capillary and a command value of the speed command circuit. In a wire bonding apparatus for a semiconductor device, the wire bonding apparatus includes a speed control circuit that causes a current proportional to the current to flow through the DC motor to match a moving speed of the capillary with a command value of the speed command circuit, wherein the speed control circuit allows current to flow through the DC motor. A current limiting circuit that variably sets an upper limit value of the current is provided, and a predetermined speed profile is output from the speed command circuit and the upper limit value of the current limiting circuit is set until the capillary approaches a predetermined distance from the electrode. After the capillary reaches the predetermined distance and until the capillary contacts the electrode and finishes bonding, the speed command circuit outputs a constant speed command value and the upper limit value of the current limit circuit is set to a sufficiently large value. A wire bonding device characterized by setting a predetermined value corresponding to bonding pressure.