ABB 5SHY55L4500 Thyristor (IGCT) Module

The provided text discusses stress relief strategies for improving the reliability of high-power modules, particularly focusing on optimizing the design of terminal leads, managing stress in bond wires, and addressing issues related to self inductance in the current path.

Stress Relief for Reliability:

1. Terminal Lead Design Optimization:
   • Balancing low electrical resistance and flexibility is crucial in designing terminal leads.
   • Thermal cycles cause height changes in the fixed and soldered terminals.
2. Stress-Relieving Measures:
   • Stress-relief features are incorporated into the terminals to reduce stress on solder joints, preventing early failure.
   • Thermal cycling-induced stress is evaluated using tensile testing, demonstrating improved flexibility in newer designs.
3. Trade-Off for Electrical Resistance and Flexibility:
   • Achieving a balance between low electrical resistance and good flexibility is a key consideration in terminal lead design.
4. Bond Wires and Electrical Resistance:
   • Bond wires contribute to electrical resistance, and a trade-off situation, similar to main terminals, is considered.
   • Stress in bond wires arises from the coefficient of thermal expansion (CTE) mismatch between aluminum bond wires and the silicon chip.
5. Limitations in Bond Wire Design:
   • The number and size of bond wires are constrained by the available space on the active area of the chip.
   • High current density within bond wires can lead to thermal stress and potential failure.
6. Self Inductance Reduction:
   • Minimizing self inductance is crucial for optimal current path performance.
   • Good performance is achieved when conductors with opposite current flow are close, compensating for each other’s magnetic field.
7. Development Trends:
   • Current HiPak modules are rated for specific terminal currents for IGBTs and diodes.
   • New chip technologies drive the need for even higher terminal current ratings.
   • Ongoing development aims at designing terminals with lower resistance and enhanced cooling capabilities, especially with trends toward higher operating temperatures.

Conclusion:

The text emphasizes the importance of stress relief measures in terminal lead design, managing stress in bond wires, and addressing self inductance to enhance the reliability and performance of high-power modules. If you have further questions or need additional information, feel free to ask.