Wire Bonding — Gold and Copper

Category: Packaging

Process Overview

Wire bonding is a critical packaging process used to create electrical interconnections between semiconductor dies and package leads or substrates. Gold (Au) and copper (Cu) wires are commonly employed due to their conductivity, reliability, and cost-effectiveness. The process uses ultrasonic energy, heat, and pressure to form metallurgical bonds at the wire-to-pad and wire-to-substrate interfaces. In data center and high-performance semiconductor manufacturing, wire bonding enables high-density packaging while maintaining signal integrity and thermal performance.

Gold bonding is preferred for fine-pitch applications and high-reliability environments, while copper bonding offers lower costs and better thermal conductivity. The process is widely used in power modules, RF devices, and advanced packaging for AI accelerators and network processors. Compliance with standards like JEDEC JESD22 (reliability testing) and SEMI E14 (wire bonding equipment specifications) ensures consistency and quality.

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Key Process Parameters

| Parameter | Gold Bonding Range | Copper Bonding Range |
|-------------------------|-------------------------|-------------------------|
| Temperature (°C) | 150–250 | 200–300 |
| Bonding Force (g) | 50–150 | 100–250 |
| Ultrasonic Power (W) | 50–150 | 100–200 |
| Bonding Speed (mm/s) | 1–3 | 1–2.5 |
| Wire Diameter (µm) | 25–50 | 25–45 |

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Equipment & Parts Required

1. Capillaries

   • Purpose: Guide and shape the bonding wire, forming precise bond loops.
   • Caladan Integration: Caladan’s high-precision capillaries (e.g., Model C-3000 series) are optimized for Au/Cu wire diameters and feature wear-resistant coatings to extend lifespan.

2. Bonding Wire (Au/Cu)

   • Purpose: Conducts electrical signals between die and substrate.
   • Caladan Integration: Caladan supplies Au/Cu wire with ISO 9001-certified purity and consistency for high-yield bonding.

3. Clamps

   • Purpose: Secure the die and substrate during bonding to prevent misalignment.
   • Caladan Integration: Caladan’s vacuum clamps (e.g., V-Clamp 2.0) ensure stability under high-force bonding conditions.

4. USG Transducers

   • Purpose: Convert electrical energy into ultrasonic vibrations for bond formation.
   • Caladan Integration: Caladan’s high-efficiency USG transducers deliver 95%+ energy conversion, critical for Cu bonding’s higher power demands.

5. Vision Systems

   • Purpose: Align bonds and inspect quality via real-time imaging.
   • Caladan Integration: Caladan’s AI-enhanced vision systems (e.g., VisionX 4K) achieve sub-micron alignment accuracy, reducing rework.

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Common Issues & Troubleshooting

1. Poor Ball Formation

   • Cause: Incorrect temperature/power settings or worn capillary tips.
   • Fix: Calibrate temperature to 180–220°C for Au/Cu, replace capillary if wear exceeds 5 µm.

2. Wire Breaks During Bonding

   • Cause: Insufficient tension or USG transducer misalignment.
   • Fix: Adjust clamping

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Parts for This Process

Looking for parts to support this process? Caladan Semi stocks used and refurbished components including: Capillaries, bonding wire, clamps, USG transducers, vision systems.

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