Optimizing Signal Integrity in 3-D Sensor Packaging Using Embedded Inverted T-Slot Shielding Structures

To address the escalating signal integrity (SI) challenges in high-frequency 3D sensor packaging, this study proposes an embedded inverted T-slot shielding structure integrated within redistribution layers (RDL). Unlike conventional surface-level shielding, the inverted T-slot provides three-dimensional electromagnetic confinement by intercepting lateral and vertical fields. Full-wave and circuit co-simulations demonstrate up to 20 dB reduction in near-end coupling (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sub>), with a notable 35 dB improvement in return loss (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub>) and a 1.3 dB reduction in insertion loss (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sub>) across the 0–50 GHz band. Comparative analysis across silicon and glass substrates highlights material-dependent optimization strategies, where glass substrates yield superior impedance matching and silicon substrates achieve stronger coupling suppression. The proposed structure remains fully compatible with standard RDL manufacturing processes, offering a practical and scalable solution for high-density sensor platforms, 5G/6G transceivers, and mmWave communication systems requiring robust SI performance.