- Gold Ball Wire Bonding (Thermosonic @ +150°C).
- Gold Wedge Wire Bonding (Thermosonic @ +150°C).
- Aluminum Wedge Wire Bonding (Ultrasonic @ +25°C).
- Ribbon Bonding for high frequency applications 20-100 GHz.
Gold Ball Wire Bonding and stitch bonding is the most widely used assembly process in the semiconductor industry to interconnect the die circuitry to the package or substrate. This method is commonly known as Thermosonic Gold Ball Wire Bonding. It uses force, power, time, temperature up to 150°C and ultrasonic energy.
Aluminum and Gold Wedge Wire Bonding process is called wedge-to-wedge bonding. The difference between the two processes is that aluminum wedge wire bonding is an Ultrasonic bonding process done with temperature at 25°C and gold wedge wire bonding is a Thermosonic bonding process with temperature up to 150°C.
Ribbon Bonding is recommended for high frequency applications of 20-100 GHz. The higher the frequency, the shorter the wire needs to be for the circuit to function the way it is designed. Ribbon wire inherently carries lager amounts of power and generates stronger wire pull interconnects that last longer.
- Wire Bonding wire diameter: 18µm to 50µm (0.70 mil to 2.0 mil).
- Ribbon Bonding: 50x12um (2.0×0.5 mil) up to 250x25um (10×1 mil).
- Ultra-Fine Pitch Wire Bonding: ≥40µm (1.60 mil) bond pad pitch capability.
- Wire Bond Area (Small) – Au Ball: 56mm x 80mm (2.20”x3.15”).
- Wire Bond Area (Large) – Al & Au Wedge: 250mm x 200mm (10.0”x8.0”).
- Loop height: 3x wire diameter minimum, typical 100-250µm (4 mil to 10 mil).
- Wire length (Au Ball): 500µm (20 mil) up to 150x wire diameter.
- Wire length (Al & Au Wedge): 500µm (20 mil) up to 200x wire diameter.
- ENEPIG: Ni 3-6µm (118-236 µin), Pd 0.05-0.3µm (2-12 µin), Au ≥0.1µm (≥4 µin).
- ENIG: Ni 3-6µm (118-236 µin), Au ≥0.05µm (≥2 µin).
Different pad metallization on the IC chip are used for wire bonding. Therefore, different metallurgical systems can be formed with different reliability behaviors.
- Au Wire to Al Bond Pads on the IC chip. (Gold Ball or Gold Wedge) Gold wire bonded to an aluminum pad is the most used wire bonding process in the semiconductor industry for IC Packaging.
- Au Wire to Au Bond Pads on the IC chip. (Gold Ball or Gold Wedge) Gold wire bonded to a gold bond pad is the most reliable wire bonding process. The bond is not subject to corrosion, intermetallic formation, or degradation.
- Al Wire to Al Bond Pads on the IC chip. (Aluminum Wedge) Aluminum wire bonded to an aluminum bond pad is extremely reliable. The bond is not subject to corrosion, intermetallic formation, or degradation.
- Al Wire to Au Bond Pads on the IC chip. (Aluminum Wedge) Not recommended wire bonding because of reliability concerns.