JPH05259212A - Wire bonding device and discriminating method for polarity of semiconductor component using it - Google Patents

Abstract

PURPOSE:To automatically discriminate the polarities of IC chip pads (electrodes), which are semiconductor components, by applying positive or negative micro-current on the pads and detecting the current values. CONSTITUTION:A bonding device is provided with a power source circuit 40, a switching circuit 41 and a current detecting circuit 42. After locking a ball formed on the leading edge of wire by bonding tool, the ball is permitted to make contact with an electrode arranged on a semiconductor component by the movement of a bonding arm so as to apply micro-current of the different polarity by switching of the switching circuit and the polarity of the electrode of the semiconductor component is discriminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire bonding apparatus for connecting a semiconductor component (IC chip), which is a component to be bonded, and a lead, for wire bonding, and particularly to an IC chip as a semiconductor component. Wire bonding apparatus capable of automatically determining the polarity of the pad by applying a small positive or negative current to each pad (electrode) and detecting the respective current values, and determining the polarity of a semiconductor component using the apparatus Regarding the method.

[0002]

2. Description of the Related Art Conventionally, in order to perform a bonding connection between a pad of an IC chip and a lead by using this type of wire bonding apparatus, the wire is attached by a capillary as a bonding tool provided at the tip of a bonding arm. The wire is held, brought into contact with the surface of the target pad or lead, and a part of the wire having a ball formed at the tip thereof is crushed using the capillary and thermocompression-bonded to be welded. At this time, ultrasonic vibration may be applied to the tip of the wire at the same time.

A process of performing this wire bonding is shown in FIG.
Describing with reference to FIG. 5, when the wire bonding is attempted to the pad on the IC chip 25 mounted on the bonding stage 26, the capillary having the wire 9 having the ball formed at the tip by the electric discharge means (not shown) is inserted. 7
Is positioned by moving an XY table that is movable in a two-dimensional direction based on information from an image pickup device (not shown), and then the capillary 7 is lowered as shown in FIG. Perform thermocompression bonding.

In this step, → moves the bonding arm downward at a high speed, and → moves it at a low speed. At this time, the clamp 8a is open. Then this first
When the connection to the bonding point is finished, the bonding arm 1 moves upward in FIG. 5, that is, in the Z-axis direction while the clamp 8a remains open in →, and the clamp 8a moves as shown in accordance with a predetermined loop control. In the open state, the wire 9 is pulled out and connected to the lead 27 which is the second bonding point indicated by.

After this connection, the clamp 8a is closed while the wire 9 is pulled out from the tip of the capillary 7 by a predetermined feed amount f as shown by. In this state, the wire 9 is cut as shown in the process of further raising the bonding arm 1 to a predetermined height, a ball is formed again at the tip of the wire using an electric torch, and the clamp 8a is opened. Return to the state of. Wire bonding is performed by such a series of steps.

The wire is connected between the pad on the IC chip and the corresponding lead by the above wire bonding process. The pad serving as the first bonding point or the lead serving as the second bonding point. It has been conventionally practiced to apply a current to the wire to determine whether or not the wire is securely connected, that is, whether or not the bonding is not adhered.

[0007]

However, when a current is applied to a wire through a pad serving as a first bonding point or a lead serving as a second bonding point as in the prior art to determine whether or not bonding has failed, particularly in recent years. I
In the situation where the C chip is becoming thinner and more integrated, there is a problem that it may be destroyed by applying a voltage to a semiconductor component or may be destroyed due to generation of static electricity.

Therefore, conventionally, the polarity of the pad of the IC chip is input as data each time, for example, at the time of self-teaching based on the paper surface information obtained from the user or the like and stored in the memory of the control circuit (not shown). In addition, a method used to detect non-sticking at the time of bonding is adopted.

However, in such a method, since it is necessary to obtain and input each data each time the type of IC chip to be wire-bonded changes, a wire-bonding apparatus intended for high-speed processing is not available. There is a drawback that speedy correspondence cannot be achieved.

Therefore, the present invention has been made in view of the above-mentioned drawbacks of the prior art, in which a small positive or negative current is applied to a pad (electrode) of an IC chip as a semiconductor component to detect the respective current values. An object of the present invention is to provide a wire bonding apparatus capable of automatically determining the polarity of the pad and a semiconductor component polarity determining method using the apparatus.

[0011]

According to the present invention, there is provided a bonding stage on which a frame having semiconductor parts mounted thereon is mounted, a bonding arm for holding a bonding tool having a wire inserted therein, and a movable bonding arm. A support mechanism for supporting, a clamp means provided above the bonding tool for gripping the wire by the opening / closing mechanism and cutting the wire, and a wire held by the clamp means and fed from the tip of the bonding tool. In a wire bonding apparatus provided with electric discharge means for forming a ball at an end, the wire bonding apparatus includes a power supply circuit, a switching circuit, and a current detection circuit, and the bonding tool is formed at a wire tip. After moving the bonded ball, move the bonding arm. It is one that is configured to determine a polarity of the semiconductor component of the electrode by flowing a different polarities small current is brought into contact with the electrodes arranged in more said semiconductor component is switched by the switching circuit. According to the present invention, in the above bonding apparatus, after the ball formed at the tip of the wire is locked by the bonding tool, the ball is brought into contact with the electrode provided on the semiconductor component by the movement of the bonding arm. Then, the polarities of the electrodes of the semiconductor component are discriminated by passing minute currents of different polarities.

[0012]

Embodiments of the present invention will now be described with reference to the drawings. 1 shows the main part of the wire bonding apparatus according to the present invention, and FIG.
FIG. It should be noted that components having the same configuration and the same function as those of the conventional device will be described using the same reference numerals and detailed description thereof will be omitted.

In this wire bonding apparatus, as shown in FIG. 1, a bonding arm 1 composed of a holding frame 1a and a horn 1b can swing together with a swing arm 2 around an axial center of a support shaft 3. The bonding arm 1 is firmly fitted to the support shaft 3, and the swing arm 2 is swingably fitted to the support shaft 3. The support shaft 3 is mounted on an XY table or the like (not shown) that is movable in two dimensions. An ultrasonic transducer (not shown) for vibrating the horn 1b is incorporated in the holding frame 1a. Swing arm 2 and holding frame 1
A solenoid 4a and an electromagnetic attraction piece 4b are fixed to each other in a, and when the bonding arm 1 is swung, the solenoid 4a is energized from a power source (not shown) and the solenoid 4a is electromagnetically coupled to the solenoid 4a. The bonding arm 1 and the swinging arm 2 are fixed and coupled to each other by generating a suction force between the swinging arm 4 and the suction piece 4b. A fixed adjustable stopper 6 is provided. A magnet 5a and a coil 5b are attached to the swing arm 2 and the holding frame 1a, respectively, in front of the electromagnetic attraction means. These magnet 5a and coil 5b
Constitutes a means for generating a suction force for urging the tip of the bonding arm 1 at the time of bonding, that is, the portion holding the capillary 7 as a bonding tool downward in FIG.

A clamp arm 8 is provided at the tip of the swing arm 2, and a wire 9 is gripped at the tip of the clamp arm 8 by an opening / closing mechanism (not shown) composed of a solenoid and a spring. A clamp 8a is provided as a clamping means for cutting by the method described later. Further, below the capillary 7, an electric torch 10 as an electric discharge means is arranged on a vertical shaft (not shown) so as to be rotatable by the action of an actuator or the like, and around the capillary 7 along with the movement of the bonding arm 1. It has a rotatable structure. This electric torch 10 applies a predetermined voltage to form a ball at the tip of the wire 9. Further, above the clamp 8a, fixedly supported by a frame (not shown), a predetermined tension is applied to the wire 9 so that the wire 9 is always held straight up to the tip of the capillary 7 of the bonding arm 1. A tension clamp 11 that can be opened and closed by an opening / closing mechanism (not shown) is provided, and the wire 9 is further wound by a spool 36 via a guide 12.

As shown in FIG. 2, a support shaft 15a is provided on the rear end side of the swing arm 2, and the arm side cam follower 15 and the swing base 16a are rotatable around the support shaft 15a. Has become. A bearing guide 16b is fixed to the swing base 16a at one end, and a preload arm 16d is rotatably attached to the other end of the bearing guide 16b via a support pin 16c. A support shaft 17a is provided at a free end of the preload arm 16d, and a cam follower 17 is rotatably attached to the support shaft 17a. A preload spring 16e, which is a tension spring, is stretched over the tip of the preload arm 16d and the tip of the swing base 16a, and the arm side cam follower 15 and the cam follower 17 have a cam 18 formed in a substantially heart shape. Is pressed against the cam surface, which is the outer peripheral surface of the. The two contact points of the arm side cam follower 15 and the cam follower 17 with respect to the cam 18 are located with the center of rotation of the cam 18 in between.

A frame structure is formed by the swing base 16a, the bearing guide 16b, and the preload arm 16d, and is collectively referred to as a swing frame 16.
The bearing guide 16b as a component of the swing frame 16 is in contact with the outer ring of the radial bearing 20 attached to the cam shaft 19 to which the cam 18 is fitted. The cam 18 is rotated by the torque applied to the cam shaft 19 by the motor 21. The height position of the capillary 7 as a bonding tool is detected by a rotary encoder (not shown) connected to the support shaft 3.

Next, I as a semiconductor component according to the present invention
An apparatus and method for discriminating the polarity of the pad of the C chip will be described with reference to FIGS. 3 and 4. In addition, in FIG.
It is a figure which shows the outline of a structure of the apparatus which discriminate | determines the polarity of the pad of the IC chip which concerns on this invention, and FIG. 4 is a figure which shows the detail of the power supply circuit and switching circuit which are shown in FIG. 3, and is an example of these circuits. ..

As shown in FIG. 3, a power supply circuit 40 is provided between one end of the clamp 8a and the bonding stage 26.
The switching circuit 41 and the current detection circuit 42 are connected.
The power supply circuit 40 is a separate system from the power supply applied to the electric torch 10 shown in FIG. 1, and is used to pass a minute current through the wire 9 and is composed of a DC constant current power supply. The switching circuit 41 is composed of a switch for switching between positive and negative. Further, the current detection circuit 42 detects the current value of the current switched to the positive or negative by the switching circuit 41. When the clamp 8a grips the wire 9 by the opening / closing mechanism according to a command from a control circuit (not shown), a positive or negative current flows through the wire 9 and the IC pad (through the ball formed at the tip of the wire 9). 25a _{1 to} 25a _n ), I to which the IC pad is connected
Bonding stage 2 through C pellets and leads
6 is input to the other terminal of the power supply circuit 40. At this time, although the pad and the IC pellet cannot be said to be conductive, a closed loop is formed on the circuit as a resistance component. Therefore, the current detection circuit 42 can determine the polarity of the pad by detecting the current value when the switching circuit 41 switches between positive and negative.

It is possible to determine the polarity of the pads by performing such an operation for all the pads during the self-teaching when setting the conditions of the bonding apparatus, and the data obtained by this work is shown in the drawing. By storing it in the memory of the control means,
Even if the type of semiconductor component is changed, it is possible to easily deal with it.

By the way, as shown in FIG. 4, the power supply circuit 40 is constituted so as to act as a constant current power supply by a Zener diode ZD or the like. The power supply circuit 40 is connected to the switching circuit 41. The changeover circuit 41 is composed of positive or negative changeover switches SW ₁ and SW ₂ which are changed over by a control signal from a control means (not shown). That is, when the switch SW _{1 that} is interlocked and switched as shown in FIG. 4 is turned on, a positive current flows through the wire W through the lead frame L / F and the other switch SW ₁ . Conversely, when the switch SW ₂ is turned on, SW ₁ is turned off and the lead frame L /
It flows in the opposite direction through F, the wire W and the other switch SW ₂ . These switches SW ₁ and SW ₂
The timing of switching of is controlled by the control means. Therefore, it is possible to easily know the polarities of the pads 25a _{1 to} 25a _n as data by switching the switches SW ₁ and SW ₂ as described above, and by effectively utilizing these data when detecting non-bonding of the semiconductor, It is possible to avoid destruction of parts.

In this embodiment, the power supply circuit 41, the switching circuit 41 and the current detection circuit 42 are directly connected, but the current flowing through the pad or the like through the wire 9 can be detected as a closed loop. Of course, other circuit configurations may be used as long as they are provided. Moreover, it is also possible to appropriately change and use it within the scope of the present invention.

[0022]

As described above, according to the present invention,
There is an effect that a positive or negative minute current is passed through a pad (electrode) of an IC chip as a semiconductor component, each current value is detected, and the polarity of the pad can be automatically determined.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of a wire bonding apparatus according to the present invention.

2 is a cross-sectional view taken along the line AA of FIG.

FIG. 3 is a diagram showing an outline of a configuration of an apparatus for discriminating the polarity of an IC pad according to the present invention.

FIG. 4 is a circuit diagram showing details of a power supply circuit and a switching circuit shown in FIG.

FIG. 5 is an explanatory diagram showing a bonding process of a conventional wire bonding apparatus.

[Explanation of sign]

 1 Bonding Arm 2 Swing Arm 3 Support Shaft 7 Capillary 8 Clamp Arm 8a Clamp 9 Wire 10 Electric Torch 15 Arm Side Cam Follower 17 Cam Follower 18 Cam 16 Swing Frame 21 Motor 40 Power Supply Circuit 41 Switching Circuit 42 Current Detection Circuit

Claims (2)

[Claims] 1. A bonding stage on which a frame on which a semiconductor component is mounted is placed, a bonding arm for holding a bonding tool having a wire inserted therein, and a support mechanism for movably supporting the bonding arm.
Clamping means provided above the bonding tool for holding the wire by an opening / closing mechanism to cut the wire, and forming a ball at the end of the wire held by the clamping means and fed from the tip of the bonding tool. In the wire bonding apparatus, the wire bonding apparatus includes a power supply circuit, a switching circuit, and a current detection circuit, and the bonding tool locks the ball formed at the tip of the wire. After that, the polarity of the electrode of the semiconductor component can be determined by contacting the electrode provided on the semiconductor component by the movement of the bonding arm and causing a minute current of different polarity to flow by being switched by the switching circuit. A wire bonding apparatus characterized in that 2. A bonding stage on which a frame having semiconductor components mounted thereon is mounted, a bonding arm for holding a bonding tool having a wire inserted therein, and a support mechanism for movably supporting the bonding arm.
Clamping means provided above the bonding tool for holding the wire by an opening / closing mechanism to cut the wire, and forming a ball at the end of the wire held by the clamping means and fed from the tip of the bonding tool. A wire bonding apparatus comprising: an electric discharge means for locking the ball formed at the tip of the wire with a bonding tool, and then moving the bonding arm to the electrode provided on the semiconductor component. A polarity discriminating method in a wire bonding apparatus, characterized in that the polarities of electrodes of the semiconductor component are discriminated by bringing balls into contact with each other and passing minute currents of different polarities.