Articles techniques et présentations

In power electronics applications, microelectronic chips face swift temperature changes during operation, characterized by heat pulses of sub-millisecond duration with temperatures rising by hundreds of Kelvin. Over time, these conditions may lead to degradation in the metallization layers, posing a significant issue for reliability. Silicon-based test chips with a 20-μm-thick copper metallization and integrated active heating have been developed to simulate power pulses with heating rates on the scale of 1 K/µs [1]. These conditions closely mirror those found in real-world applications and allow for highly controlled fatigue testing. However, due to the extremely short duration of these pulses, experimental data is restricted to the power applied, the electrical behavior of the metallization, and the local temperature in specific temperature sensing structures. To ascertain the thermal loading on the metallization, thermal simulations are required.

A user-friendly application, developed with COMSOL Multiphysics, enables such simulations. This application generates a 3D model of any test device for a given technology using its GDS layout using the ECAD Import and Design modules. The Heat Transfer module's Thin Layer feature is employed to model functional layers that don't require detailed resolution, thus optimizing for minimal computational effort.

The design of this app (fig. 1) incorporates the Application Builder form template to leverage predefined basic visualizations and auto-generated input fields for parameters. It allows users to upload GDS layout files and experimental data directly from local storage or a proprietary data storage system through a Java client. On completion of the transient thermal simulation, the app offers a visual representation of the temperature field, enabling users to interactively create local temperature evaluations.

This app streamlines the process of conducting thermal simulations without requiring in-depth knowledge of the COMSOL Multiphysics GUI. Access to temperature field data facilitates a far superior interpretation of, for instance, metallographic analysis compared to interpretations solely relying on local sensor temperatures.