Product Overview
The nano silver sintering machine is a precision pressure-assisted low-temperature sintering system designed for die attach and chip interconnection in wide-bandgap semiconductor packaging. It implements low-temperature nano-silver sintering technology (LTJT) to replace traditional leaded solder, forming dense silver bonding layers via solid-state atomic diffusion of silver nanoparticles without melting the silver material itself.
This equipment integrates servo pressure, multi-zone heating, high vacuum / controlled forming gas atmosphere, gas purification and water cooling subsystems. It realizes programmable heating, holding, pressurization and cooling curves. The sintered silver joint features ultra-high thermal & electrical conductivity, high shear strength and outstanding high-temperature long-term reliability, which is the core bonding equipment for SiC/GaN power devices, high-power lasers, automotive power modules and high-brightness LED packaging.
Core Working Principle
After nano silver paste is dispensed or stencil-printed on the substrate, the die is mounted. The assembly enters the chamber for solvent pre-drying. Under vacuum or inert gas protection, the system applies precise mechanical pressure while heating to 200–300°C. Nanoscale silver particles diffuse and form metallurgical necking between particles, organic carriers decompose and volatilize, and the silver layer densifies to create a permanent metallic bond between die and substrate.
Key Features
- Independent upper/lower heating platens + multi-channel PID control: Closed-loop thermocouple feedback, low overshoot, excellent temperature uniformity across the whole sintering zone.
- High-precision servo pressure system: Stepless programmable pressure ramping, constant pressure and pressure relief; pressure distribution uniform, low stress for large-area chips.
- Vacuum + controlled atmosphere: Dry pump + molecular pump for high vacuum; 4 gas channels for N₂ / forming gas (H₂/N₂ mixed) to reduce surface oxidation and minimize void rate.
- Fully programmable recipe management: Store multiple sintering recipes; real-time curve recording for traceability, suitable for R&D and mass production.
- Low void sintering: Sintered silver joint void ratio can be controlled below 3% under optimized parameters.
- Safety interlock: Chamber door interlock, over-temperature, over-pressure, water flow and gas leakage protection.
Typical Applications
- SiC, GaN wide bandgap power semiconductors, IGBT, MOSFET power modules
- Automotive power electronics, new energy vehicle inverter packaging
- High-power laser diodes, RF power devices, concentrated PV cells
- High-brightness LED, MEMS, thermoelectric modules
Technical Specification Table
表格
| Item | Specification |
|---|---|
| Sintering Working Area | 220 × 220 mm (custom: 160mm / 320×420mm optional) |
| Max Sintering Temperature | 320 °C |
| Working Temperature Range | RT ~ 320 °C |
| Temperature Uniformity | ≤ ±3 °C (full platen) |
| Temperature Control Precision | ±1 °C |
| Heating Rate | 1 ~ 30 K/min programmable |
| Cooling Rate | 1 ~ 20 K/min, water + nitrogen auxiliary cooling |
| Pressure Type | Servo mechanical pressure |
| Pressure Range | 0 ~ 30 MPa (custom up to 35 MPa) |
| Pressure Control Accuracy | ±1% FS |
| Pressure Uniformity | ≤ ±3% across platen |
| Max Total Press Force | 100 kN (10 ton) |
| Vacuum System | Dry pump + turbomolecular pump |
| Ultimate Vacuum | ≤ 5×10⁻² Pa |
| Chamber Leak Rate | ≤1×10⁻⁵ Pa·m³/s |
| Gas Channels | 4 channels (N₂, Forming gas optional) |
| Oxygen Content in Chamber | ≤50 ppm (under protective gas) |
| Platen Material | SiC silicon carbide |
| Tooling Material | Titanium alloy |
| Power Supply | 380V AC, 3-phase, 25~50A |
| Cooling | Closed-loop circulating water cooling |
| Outer Dimension (L×W×H) | 2480 × 1650 × 2400 mm |
| Machine Weight | ~3000 kg |
| Recipe Storage | 99 groups of process recipes |
| Data Output | Real-time temperature / pressure curve, CSV export |
| Compatible Wafer Size | 2”,4”,6” wafer & discrete power chips |
| Post-sinter Shear Strength | 25–40 MPa (depends on nano silver paste & process) |
Process Sequence (Standard Recipe)
- Loading → Chamber close & leak check
- Pre-drying: 80~120°C, vacuum, remove solvent
- Ramp to sinter temperature
- Apply target pressure + temperature holding (main sinter stage)
- Slow cooling under protective atmosphere
- Pressure release → chamber venting → unload
Advantage vs Traditional Soldering
表格
| Property | Nano Silver Sinter Joint | High-Temp Solder |
|---|---|---|
| Thermal Conductivity | 200~250 W/m·K | ~50 W/m·K |
| Max Long-Term Operating Temp | >250°C | <180°C |
| Shear Strength | High | Medium |
| Intermetallic Growth | Minimal | Severe |
| Environmental | Lead-free, RoHS | Contains lead for high-temp grades |
Notes: Parameters can be customized according to customer chip size, paste formulation and production throughput requirements. Pressureless nano silver sintering model is available as alternative for stress-sensitive devices.
