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Wedge Wire Bonder
$500 (outsource prototype) → $12,000 (used bonder for production) = $12,500 total HIGH ● Required for all 48–72 electrical connections (heaters, SPADs, power, ground)Role in QLT Fabrication
Gold or aluminum wire bonding connects chip bond pads to ceramic/PCB package leads. This is the critical step that establishes all electrical connectivity to:
- 48 thermo-optic phase heater pads ● individually addressed for mesh reconfigurability
- 16 SPAD detector output pads ● high-speed signal path to readout electronics
- 8 ground/power pads ● common supply and return
- Total: ~72 wire bonds per chip
Bond Types Used at QLT
| Bond Type | Wire | Pad Material | Method | QLT Use Case |
|---|---|---|---|---|
| Wedge-wedge (Al) | 25 μm Al wire | Al or Au pads | Ultrasonic + pressure at room temp | Primary method ● no heat to chip |
| Ball-wedge (Au) | 25 μm Au wire | Au pads | Thermosonic (heat 130–200°C + US) | If Au pads specified |
| Ribbon | 2 mil Al ribbon | Low-inductance applications | Ultrasonic | Not needed for QLT |
Bond Requirements
| Parameter | Target |
|---|---|
| Pad size (chip) | 100–200 × 100–200 μm |
| Pad size (package) | 1 mm × 1 mm |
| Wire diameter | 25 μm (1 mil) Al or Au |
| Loop height | < 500 μm (to fit under package lid) |
| Bond pitch | 200 μm minimum |
| Pull strength | > 3 gf (per MIL-STD-883 Method 2011) |
| Shear strength | > 6 gf (per MIL-STD-883 Method 2019) |
| Bonds per chip | ~72 |
| Time per chip | 30–60 min (manual); 5–10 min (semi-auto) |
Recommended Configuration
| Parameter | Specification | ||
|---|---|---|---|
| Manufacturer | West Bond Inc., Anaheim, CA | ||
| Model | 7476D (45° feed) / 7600D (90° deep access) | ||
| Type | Manual wedge-wedge bonder | ||
| Wire types | Al, Au wire: 0.7–2.0 mil (17–50 μm); Au ribbon to 1×10 mil | ||
| Bonding mechanism | Ultrasonic (K~Sine 63 kHz transducer, 5 W) | ||
| Bond force range | 10–150 grams, adjustable | ||
| Heated stage | Radiant tool heat built-in (up to ~200°C for Au thermosonic) | ||
| Microscope | User-selected; Nikon SMZ-660 recommended (not included) | ||
| Stage travel | Manual XYZ single-lever micromanipulator, 8:1 ratio | ||
| Z encoder resolution | 0.001 inch | ||
| ESD protection | Electroless nickel plating; suitable for ESD-sensitive devices | ||
| Programming | 68000 microprocessor; 3 device buffers, 21 stitch bonds per wire | ||
| Display | 4-line, 40-character LCD | ||
| Power | 115 VAC, 50/60 Hz, 4A | ||
| Dimensions | 22 × 19 × 12 inches (56 × 48 × 30 cm) | ||
| Weight | 60 lbs (27 kg) uncrated | ||
| Price (new) | $18,000–$25,000 (contact West Bond for quote) | ||
| Price (refurbished) | $17,500–$18,000 (7476E model on eBay/Bridge Tronic) | ||
| Delivery (new) | 4–8 weeks | ||
| Contact | westbond.com | (714) 978-1551 | [email protected] |
| Parameter | Target |
|---|---|
| Pad size (chip) | 100–200 × 100–200 μm |
| Pad size (package) | 1 mm × 1 mm |
| Wire diameter | 25 μm (1 mil) Al or Au |
| Loop height | < 500 μm (to fit under package lid) |
| Bond pitch | 200 μm minimum |
| Pull strength | > 3 gf (per MIL-STD-883 Method 2011) |
| Shear strength | > 6 gf (per MIL-STD-883 Method 2019) |
| Bonds per chip | ~72 |
| Time per chip | 30–60 min (manual); 5–10 min (semi-auto) |
| Parameter | Specification | ||
|---|---|---|---|
| Manufacturer | West Bond Inc., Anaheim, CA | ||
| Model | 7476D (45° feed) / 7600D (90° deep access) | ||
| Type | Manual wedge-wedge bonder | ||
| Wire types | Al, Au wire: 0.7–2.0 mil (17–50 μm); Au ribbon to 1×10 mil | ||
| Bonding mechanism | Ultrasonic (K~Sine 63 kHz transducer, 5 W) | ||
| Bond force range | 10–150 grams, adjustable | ||
| Heated stage | Radiant tool heat built-in (up to ~200°C for Au thermosonic) | ||
| Microscope | User-selected; Nikon SMZ-660 recommended (not included) | ||
| Stage travel | Manual XYZ single-lever micromanipulator, 8:1 ratio | ||
| Z encoder resolution | 0.001 inch | ||
| ESD protection | Electroless nickel plating; suitable for ESD-sensitive devices | ||
| Programming | 68000 microprocessor; 3 device buffers, 21 stitch bonds per wire | ||
| Display | 4-line, 40-character LCD | ||
| Power | 115 VAC, 50/60 Hz, 4A | ||
| Dimensions | 22 × 19 × 12 inches (56 × 48 × 30 cm) | ||
| Weight | 60 lbs (27 kg) uncrated | ||
| Price (new) | $18,000–$25,000 (contact West Bond for quote) | ||
| Price (refurbished) | $17,500–$18,000 (7476E model on eBay/Bridge Tronic) | ||
| Delivery (new) | 4–8 weeks | ||
| Contact | westbond.com | (714) 978-1551 | [email protected] |
| Parameter | K&S 4523 (Wedge) | K&S 4524AD (Ball) | K&S 4526 (Wedge) |
|---|---|---|---|
| Type | Manual wedge bonder | Semi-auto ball bonder | Auto-stepback wedge |
| Wire | 0.7–3.0 mil Al/Au | 1.3 mil Au (ball-wedge) | 25 μm Al or Au |
| Stage temp | Heated work holder | Up to 250°C | Up to 125°C |
| Bond time | 10–120 ms (std) / 1000 ms (long) | Programmable | 10–1000 ms selectable |
| Features | Individual bond parameters | NEFO ball control, 200 programs | Auto stepback, loop control |
| Price (used) | $7,000–$20,000 | $8,000–$12,000 | $10,000–$15,000 |
| Availability | Excellent used market | Good used market | Good used market |
| Sources | eBay, LabX, AllTest | eBay, wotol.com | NIST uses this model |
Process Integration
Pre-Bond Preparation
- Clean chip pads: O₂ plasma ash (30 s, 100 W) to remove organic residue from pads
- Inspect pads: Verify pad metallization integrity under microscope (no peeling, cracking)
- Mount chip: Epoxy die-bond chip to ceramic package or PCB carrier using die bonder (#08-Die-Bonder)
- Cure die attach: 150°C, 30 min (or UV cure if using UV epoxy)
- Load wire: Thread 25 μm Al wire through bonder clamp and wedge tool
- Set parameters: US power = 200 mW, force = 25 g, time = 30 ms (starting recipe for Al on Au pads)
Bond Cycle (per wire)
- Lower wedge tool to chip pad ● first bond (ultrasonic weld)
- Raise tool, feed wire to form loop (100–500 μm height)
- Lower to package pad ● second bond (ultrasonic weld)
- Clamp and tear wire
- Move to next pad ● repeat 72 times per chip
Post-Bond Inspection
- Visual inspection: 100% bonds under 50× microscope
- Pull test: Sample 5 bonds per chip ● pull > 3 gf pass (MIL-STD-883 Method 2011)
- Shear test: Sample 3 bonds per chip ● shear > 6 gf pass
- Electrical continuity: Verify all 72 connections with probe station
Vendor Options & Pricing
| Model | Manufacturer | Type | Price (New) | Price (Used/Refurb) | Delivery | Source |
|---|---|---|---|---|---|---|
| West Bond 7476D | West Bond (Anaheim, CA) | Manual wedge | $18,000–$25,000 | $17,500–$18,000 | 4–8 weeks | westbond.com |
| West Bond 7476E | West Bond | Manual wedge (updated) | $20,000–$28,000 | $17,500–$18,000 | 4–8 weeks | eBay, Bridge Tronic |
| K&S 4523 | Kulicke & Soffa (PA) | Manual wedge | Discontinued (legacy) | $7,000–$20,000 | 1–3 weeks | eBay, wotol.com |
| K&S 4524AD | Kulicke & Soffa | Semi-auto ball | Discontinued (legacy) | $8,000–$12,000 | 1–3 weeks | eBay, AllTest |
| K&S 4526 | Kulicke & Soffa | Auto-stepback wedge | Discontinued (legacy) | $10,000–$15,000 | 1–3 weeks | eBay, LabX |
| TPT HB10 | TPT (Germany) | Semi-auto, auto Z | $15,000–$22,000 | ● | 4–8 weeks | tpt-wirebonder.com |
| TPT HB16 | TPT (Germany) | Semi-auto, motor Z+Y | $20,000–$30,000 | ● | 4–8 weeks | tpt-wirebonder.com |
| F&K Delvotec 56XX | F&K Delvotec (Germany) | Semi-auto wedge | $25,000–$45,000 | $15,000–$30,000 | 4–8 weeks | fkdelvotec.com |
| Hesse Mech-EL | Hesse (Germany) | Semi-auto | $30,000–$60,000 | $15,000–$30,000 | 6–12 weeks | hfrequency.com |
| Outsource | SPT Micro, Palomar, Promex | Service | $5–$15/chip | ● | 1–2 weeks/batch | Various |
Facility Requirements
| Parameter | Specification |
|---|---|
| Power | 115 VAC, 50/60 Hz, 4A (standard outlet) |
| Compressed gas | N₂ or forming gas at 60 PSIG for ball bonding flame-off (Au wire only) |
| Vibration | CRITICAL ● vibration-isolated bench required (Newport, TMC, or Minus K) |
| Temperature | 22 ± 2°C (standard lab) |
| Humidity | 40–60% RH (prevent static; too dry = ESD risk) |
| Cleanliness | Clean area; particles on pads cause bond failures |
| Floor space | 0.6 × 0.5 m (benchtop unit) |
| Weight | 27 kg ● standard lab bench is sufficient |
| Exhaust | None required (no hazardous gases) |
| Water | None required |
| Microscope lighting | Separate LED ring light or Luxuray 21-LED illuminator |
| ESD | ESD-safe workstation: wrist strap, mat, grounded bench |
Safety & Handling
| Hazard | Risk Level | Mitigation |
|---|---|---|
| ESD damage to chip | HIGH | ESD wrist strap, conductive mat, grounded bonder chassis |
| UV from plasma clean | LOW | UV goggles during O₂ plasma pad cleaning step |
| Wire handling | LOW | 25 μm wire is fragile ● handle spools with care |
| Microscope eye strain | MEDIUM | Limit continuous bonding sessions to 2 hours; use camera + monitor |
| Repetitive stress | MEDIUM | Ergonomic seating; alternate operators for long bonding runs |
| Hot stage burns (Au bonding) | LOW–MEDIUM | Stage can reach 200°C ● warning label, cool-down protocol |