JPH0482056B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an internal lead bonding method for collectively bonding electrodes of a semiconductor pellet and inner leads of a film carrier.

[Prior Art] As the material of the bonding surface of the electrode, Au, Al, etc. are generally used. When the electrode bonding surface is made of Au, the material of the inner lead bonding surface is generally Au,
If Sn, solder, Cu, etc. are used and the electrode bonding surface is Al, the material for the inner lead bonding surface is
Au is used.

The bonding tools used for these bonds are diamond, heat-resistant metal, or the like. Additionally, the surface temperature of the welding tool that is heated during welding is generally approximately 500℃.
The above is extremely high.

[Problems to be Solved by the Invention] In the above conventional example, bonding is carried out at high temperatures, which not only adversely affects the semiconductor pellet, but also causes problems such as thermal expansion of the holder that holds the bonding tool and enlargement of the power supply line. There was a big problem with the configuration.

Conventionally, in wire bonders that connect the electrodes of semiconductor pellets and the inner leads of film carriers using wires such as Au wires and Al wires, when bonding the wires to the electrodes of semiconductor pellets, the bonding tool through which the wires are inserted is used. A method of promoting bonding by vibrating with ultrasonic waves is known.

Therefore, in so-called gigantic bonding, in which the electrodes of the semiconductor pellet and the inner leads of the film carrier are bonded together, the conventional ultrasonic wire bonding method is adopted.
One possibility is to apply ultrasonic vibration to the welding tool.

However, even if we apply ultrasonic vibration to the welding tool,
Since the bonding tool merely rubs on the inner leads and does not act in any way between the inner leads and the electrodes of the semiconductor pellet, no effect of promoting bonding can be obtained. Therefore, it is necessary to vibrate the film carrier together with the bonding tool, but the holder that holds the film carrier has a very large mass, and the load during bonding is several hundred times that of wire bonding, so it is difficult to is difficult.

To solve these problems, for example, as shown in Japanese Patent Laid-Open No. 59-111340, an ultrasonic horn and an ultrasonic vibrator are attached to the stage, and the ultrasonic vibrator is driven by a high-frequency power source. A known device is one in which sonic vibrations are transmitted to a stage via an ultrasonic horn to cause the stage and semiconductor pellet to vibrate ultrasonically.

By the way, although not shown in the above publication,
The stage is generally fixed on an XY table that is driven in the XY directions in order to align the electrodes of the semiconductor pellet placed on the stage with the inner leads of the film carrier.
However, in the above conventional technology, since an ultrasonic horn and an ultrasonic vibrator are attached to the stage,
The drive sources (X-direction drive motor and Y-direction drive motor) for the XY table that drives the stage require large capacity ones. Furthermore, since it requires an ultrasonic horn, an ultrasonic vibrator, and a high-frequency power source, it becomes an expensive device.

An object of the present invention is to provide an internal lead bonding method that does not require increasing the capacity of the drive source of the XY table, does not increase the cost of the device, allows bonding at low temperatures and low loads, and improves the reliability of semiconductor pellets. Our goal is to provide the following.

[Means for Solving the Problems] The problem with the above conventional technology is that the stage is fixed on an XY table that is driven in the In an internal lead bonding method in which an electrode of a semiconductor pellet and an inner lead of a film carrier are collectively bonded by pressing a lead with a bonding tool, a state in which the bonding tool presses the inner lead of the film carrier against the electrode of the semiconductor pellet. This problem can be solved by driving the XY table and applying horizontal vibration to the stage.

[Function] By vibrating the semiconductor pellets, bonding is promoted by the effect of ultrasonic waves, so bonding can be achieved even at low temperatures and low loads. In this case, the semiconductor pellet is vibrated by driving an XY table to which a stage is fixed. In other words, it is performed by driving the XY table originally included in the bonding equipment, without adding any special means for applying vibration to the stage.
There is no need to increase the capacity of the drive source for the XY table,
Moreover, the price of bonding equipment will not increase.

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2. The stage 2 for positioning and fixing the semiconductor pellet 1 is driven by an X-direction drive motor 3 and a Y-direction drive motor 3.
XY driven in the XY direction by the directional drive motor 4
It is fixed on the table 5. Therefore, the semiconductor pellet 1 positioned and fixed on the stage 2 is
The XY table 5 is driven to send it to the joining position. On the other hand, the film carrier 6 is fed by means not shown, and thereby the inner lead 7 provided on the film carrier 6 is fed to the joining position.

Next, as shown in FIG. 2, the bonding tool 8 descends and presses the inner lead 7 against the electrode 1a of the semiconductor pellet 1. In this state, the motors 3 and 4 are reciprocated by a certain amount in response to a predetermined signal from the control device, thereby imparting horizontal vibration to the XY table 5, that is, the stage 2. As a result, the semiconductor pellet 1 is also horizontally vibrated together with the stage 2, and the inner lead 7 and the electrode 1a are rubbed against each other, promoting bonding between them.

In this case, vibration can be applied in both the X direction and the Y direction by the motors 3 and 4. Furthermore, since vibration is applied by the motors 3 and 4, even if the weight is relatively large, the vibration can be sustained by the motor torque. By using pulse motors for the motors 3 and 4, the amplitude can be changed freely.

As a result of the experiment, the vibration of stage 2 has an amplitude of 1~
5 μm, vibration frequency is 100 cycles to 10 kilocycles,
When vibration was performed for approximately 5 to 100 msec, the heating temperature was 200 to 400°C, and the pressing load of the welding tool 8 was 10 to 80°C.
Very good bonding was obtained even at

[Effects of the Invention] As is clear from the above description, according to the present invention, since the semiconductor pellet side having a small mass is vibrated, it is easy to implement, and ultrasonic bonding can be performed by applying vibration to the semiconductor pellet. This makes it possible to bond at low temperatures and low loads, improving the reliability of semiconductor pellets. In addition, since the XY table originally included in the bonding equipment is driven without adding any special means for applying vibration to the stage, there is no need to increase the capacity of the drive source for the XY table, and the price of the bonding equipment increases. Not at all.

[Brief explanation of the drawing]

1 and 2 are explanatory front views showing one embodiment of the method of the present invention. 1... Semiconductor pellet, 1a... Electrode, 2...
Stage, 6...Film carrier, 7...Inner lead, 8...Joining tool.

Claims (1)

[Claims] 1. A stage is fixed on an XY table that is driven in the XY directions, and a bonding tool is used to press the inner lead of the film carrier against the electrode of the semiconductor pellet positioned and placed on this stage to connect the electrode of the semiconductor pellet and the inner lead of the film carrier. In the internal lead bonding method for bonding the semiconductor pellets at once, the XY table is driven with the bonding tool pressing the inner leads of the film carrier against the electrodes of the semiconductor pellet to apply horizontal vibration to the stage. An internal lead joining method characterized by: