Change – Announcement of Appointment:Appointment of Chief Commercial and Strategy Officer
- 25 Aug, 2025
Media Contact
Categories
The Growing Challenge of Ultrasonic Wedge Bonding
Ultrasonic wedge bonding is a cornerstone of semiconductor packaging, power electronics, and microelectronics assembly. It connects fine wires, often aluminum (Al) or copper (Cu), to device bond pads using ultrasonic vibration, mechanical pressure, and heat.
This process is fast and reliable but comes with significant operational challenges. The ultrasonic motion creates localized high temperatures, while repeated contact causes rapid tool wear and adhesion issues. These pain points directly impact yield, reliability, and cost efficiency in modern manufacturing.
Key challenges include:
- Elevated friction and stiction, generating excess heat
- Accelerated tool wear and micro-chipping under ultrasonic stress
- Wire and tool sticking, especially with Cu wires
- Inconsistent solder uniformity, leading to unreliable interconnects
As device designs move toward higher density and higher current capacity, conventional wedge bonding coatings are no longer sufficient.
The Limitations of Conventional DLC Coatings
Traditional Diamond Like Carbon (DLC) coatings applied via PVD or PACVD have long been used to extend wedge bonding tool life. They offer hardness values in the range of 15–30 GPa (1,500–2,800 HV) and a relatively low coefficient of friction (0.10–0.20).
But in demanding applications, particularly Cu wedge bonding, DLC coatings reveal critical weaknesses:
- Thermal instability, degrading above 300–350 °C
- Micro-chipping and wear during prolonged ultrasonic bonding
- Rising friction over time, reducing consistency
- Non-uniform solder flow, weakening bond integrity
For advanced semiconductor assembly, manufacturers require coatings that perform far beyond these limits.
i-TAC® engineered for Extreme Wedge Bonding Environments
NTI Nanofilm’s i-TAC® coating is a breakthrough solution designed to meet the harsh demands of wedge bonding. Developed with Filtered Cathodic Vacuum Arc (FCVA) technology, i-TAC® forms a multilayer structure that redefines coating performance.
i-TAC® Advantages at a Glance:
- Extreme hardness: ~2.7× harder than DLC, exceeding 70 GPa (>5000 HV)
- High thermal stability: Reliable performance up to 600 °C
- Ultra-low friction: ~0.10 COF, minimizing heat buildup and wire sticking
- Defect-free density: Preserves solder uniformity and consistent bond quality
i-TAC® vs. Conventional DLC
| Challenge | Conventional DLC Coatings | i-TAC® Advantages |
| Wear Resistance | 15–30 GPa (1,500–2,800 HV), prone to micro-chipping | ~2.7× harder (>70 GPa, >5000 HV), superior durability in high load bonding |
| Thermal Resilience | Stable only to 300–350 °C | Stable up to 600 °C, even in prolonged ultrasonic cycles |
| Friction / Stiction | COF 0.10–0.20, increases with wear | Sustained <0.10 COF, reducing heat and preventing wire sticking |
| Solder Uniformity | Degrades with tool wear | Dense, defect-free coating ensures consistent solder flow |
Real World Benefits for Manufacturers
Adopting i-TAC® delivers measurable impact across semiconductor assembly lines:
- Longer tool life: Reduced replacements and downtime
- Higher throughput: Low friction and low heat enable faster cycles
- Improved yield: Uniform solder distribution enhances bond reliability
- Fewer defects: Stable tool condition lowers rework and scrap
- Cost efficiency: Better ROI through productivity and maintenance savings
Conclusion: The Future of Wedge Bonding Reliability
As the semiconductor industry moves deeper into Cu wedge bonding and advanced packaging, the demands on bonding tools continue to rise. Conventional DLC coatings cannot keep pace with the heat, wear, and adhesion challenges of modern assembly.
NTI Nanofilm’s i-TAC® provides the industry with a proven, next-generation coating that combines extreme hardness, thermal stability, ultra-low friction, and solder uniformity to deliver unmatched bonding performance.