Compared with low-voltage or low-current IGBTs, the core challenge in producing a 1700 V / 40 A IGBT is to minimize on-state voltage drop and switching losses while maintaining a high blocking voltage. This requires exceptional performance in materials, chip design, and manufacturing techniques. SHYSEMI outlines below the key process characteristics and application areas of this device.
The unique features are reflected in the following aspects:
1.Chip Design and Structure
1.1 Ultra-Thin Wafer Processing Technology
Achieving a 1700 V withstand voltage demands a sufficiently thick N-drift region (typically over 150 µm) to endure the high electric field. However, reducing the on-state voltage drop requires this region to be as thin as possible—a fundamental trade-off. The solution involves ultra-precision thinning and grinding of silicon wafers to a thickness of 100–200 µm, far less than the 700 µm or more of conventional chips. This process demands exceptional stability to prevent wafer breakage.
1.2 Field-Stop Layer / Soft Punch-Through Design
A key technology for high-voltage IGBTs, a field-stop (N-type buffer) layer is implanted behind the N-drift region. It rapidly terminates the electric field at this layer when the device blocks high voltage, allowing thinner wafers to achieve the same rating and optimizing the trade-off between on-state voltage drop and turn-off losses.
1.3 Cellular Structure Optimization
Advanced cell designs, such as trench gate structures, create a vertical channel within the silicon. This increases cell density, improves current handling, and further lowers on-state voltage drop for a given chip area.
2.Backside Processing
2.1 Precision Ion Implantation and Laser Annealing
The P⁺ collector region and N⁺ field-stop layer are formed on the backside of the thinned wafer using high-precision ion implantation. Laser annealing replaces traditional thermal annealing to activate dopants while minimizing the heat-affected zone and preventing wafer warpage.
2.2 Metallization and Sintering
The backside collector electrode is bonded to a copper base using high-temperature silver paste or low-temperature nanosilver sintering. These methods reduce thermal and contact resistance and provide superior thermal fatigue resistance compared with traditional soldering.
3.Terminal Protection Structure
High-voltage devices require careful management of electric-field concentration at the chip edges to avoid premature breakdown. Complex peripheral protection structures include:
- Field Rings / Field Plates — Doped rings or metal extensions that gradually dissipate the edge electric field.
- Trench Termination — Trenches etched and filled with dielectric material to equalize the electric field.
Fabrication demands extremely precise photolithography and etching.
4.Packaging Technology
4.1 High Insulation and Thermal Conductivity
The 1700 V rating requires packaging materials with excellent dielectric strength, while the 40 A current demands very low thermal resistance.
4.2 Common Package Types
Industry-standard packages such as TO-247 Plus and TO-264 are typically used. These incorporate highly thermally conductive insulating spacers to isolate the chip from the metal housing and enable efficient heat dissipation.
4.3 Soldering and Wire Bonding
Multiple thick aluminum or copper wires are used for internal connections to handle high currents. The reliability of the die-attach (chip-to-substrate bond) is also critical.
In summary, the production process masters the "thin yet robust" balance by combining sophisticated structural designs (field-stop layers, trench gates) with advanced techniques such as ultra-thin wafer processing, backside laser annealing, and precise terminal protection. This synergy delivers high blocking voltage, low loss, and outstanding reliability.
5.Main Application Areas
With its high voltage rating and medium current capability, the 1700 V / 40 A IGBT is widely used in industrial applications operating at high DC-bus voltages, including:
Photovoltaic / Solar Inverters — String inverters in large-scale photovoltaic plants (DC bus up to 1000–1500 V) use 1700 V IGBTs for safe power switching in boost and inverter circuits.
Industrial Motor Drives — Medium- to high-power variable-frequency drives and servo drives powered by 380 V / 400 V three-phase AC. The 1700 V rating provides additional safety margin over standard 1200 V devices.
Uninterruptible Power Supplies (UPS) — High-power three-phase UPS systems, especially online double-conversion models, require high-voltage switching devices for increased power density and efficiency.
Induction Heating and Welding Equipment — Power conversion circuits for medium- to high-power induction furnaces and welding machines.
Electric Vehicle Charging Stations — AC-DC and DC-DC conversion modules in DC fast-charging stations.
Auxiliary Power Supplies for Rail Transit — Used in auxiliary systems such as air conditioning and lighting, complementing higher-power traction modules.