X-Wire™ Technology > Background


About 90% of all integrated circuit devices use extremely small wires (thinner than a human hair) called wire bonds to make internal electrical connections between the semiconductor die and device substrate pads. The method to attach these very fine wires is called wire bonding and although the process was initially developed over 50 years ago, today it is still used in mainstream high volume manufacturing throughout the world.


Wire Bonding


Wire bonding involves the use of special wire bonding equipment that applies pressure, temperature and ultrasonic energy to the bonding wire to form interconnecting welds between the semiconductor die and device substrate pads. There are two types of wire bonds that are formed: ball bonds and wedge bonds.

A brief summary of one cycle of the wire bonding process is outlined below. This cycle may repeat thousands of times in order to complete all the wire bonded electrical connections within a single integrated circuit device.

1. Bonding wire on a spool passes through a capillary tool and down to meet an electrode where an electrical spark is used to melt the tip of the bonding wire to form a free-air-ball (sphere) approximately 2x the diameter of the wire.

2. Thermosonic (ultrasonic plus thermal) energy is applied to the ball through the capillary tool to weld the first end of the wire to the metal-plated semiconductor die pad and form a ball bond.

3. The capillary tool moves following a specific trajectory path to form a wire loop above the connecting device substrate pad.

4. The capillary tool then descends and again applies thermosonic energy to weld the second end of the wire end to the metal-plated device substrate pad to form a wedge bond.

5. The capillary tool then makes a final movement to cut the wire from the wedge bond and extend a fresh tail length of wire for the free-air-ball of the next wire bond.