Forward Bonding

Forward Bonding is a wire bonding sequence where the first bond (ball) is made on the die pad and the second bond (stitch) on the lead frame or substrate.

## What Is Forward Bonding?

  • Sequence: Ball bond on die → Loop → Stitch bond on lead
  • Prevalence: Standard method for >80% of wire bonding
  • Advantage: Ball bond's strength protects sensitive die pads
  • Contrast: Reverse bonding places first bond on substrate

## Why Forward Bonding Is Standard

Ball bonds are mechanically stronger and more reliable than stitch bonds. Placing the ball on the critical die pad optimizes reliability.

Forward Bonding Sequence:Step 1: Ball on Die Step 2: Form Loop Step 3: Stitch on Lead FAB ╭────╮ ╭────╮ │ │ │ │ │ ○ ← Ball ○ │ ○ ═══ ──────── ──────── │ ──────── ═══ Die Pad Die Pad │ Die Pad Lead ↓ Loop formation

Forward vs. Reverse Bonding:
| Aspect | Forward | Reverse |
|--------|---------|---------|
| 1st bond location | Die pad | Lead frame |
| Typical use | Standard | Stacked die, low loop |
| Loop height | Normal | Can be lower |
| Die pad stress | Lower | Higher |

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