Effectiveness of IC shielded packages against space radiation

This paper discusses research undertaken to evaluate and improve the effectiveness of shielded packages for protecting commercial microelectronics against ionizing dose from electrons and protons in space. The IC shielded package design data base was extended to include all important shield parameters (thickness, atomic number (Z), and edge effects). The shielding effectiveness of these packages was calculated using both forward and adjoint Monte Carlo codes, and the results verified using new methods to simulate omnidirectional electron and proton radiation exposure. Furthermore, a method was developed permitting manufacturers to describe shielded packages in such a way that their effectiveness in any orbit can be quickly and accurately calculated by the user. Finally, it was demonstrated experimentally that shielding with high atomic number shield materials does not increase SEU from proton radiation.