SHIELD USA: Leap-Ahead Organic Substrate Enabled by Fan-Out Technology, Domestic Materials, Process Innovations, and Novel EDA Workflows

This paper will present the goals and, and for the first time in public, technical progress of the SHIELD USA (Substrate-based Heterogeneous Integration Enabling Leadership Demonstration for the USA) program funded under the CHIPS and Science Act. The vision to design and develop molded core substrates that enable leap-ahead performance in organic substrate microelectronic packaging will be laid out. SHIELD USA will enable a domestic ecosystem of new materials, processes, equipment and designs proven on a series of demonstrators and product exemplars. The SHIELD USA molded-core substrates are manufactured using fan-out technology with embedded active and passive devices (e.g. inductors and capacitors), fine pitch through substrate core vias, and dual-sided redistribution layer (RDL) wiring. The current status of the engineering developments of the SHIELD USA team will be discussed.

Progress on SHIELD USA’s key features such as high aspect (AR>15) vertical interconnect blocks (VIB) will be presented. VIBs enable a vertical interconnect which is not aspect ratio limited, as it is the case for traditional approaches of through-mold vias, mechanical or laser drilled vias and through-silicon or through-glass vias. The VIB multi-layer wiring is first fabricated on a planar silicon wafer, then singulated into blocks of interconnects, rotated by 90 degrees during placement, and then embedded into the molded substrate core to form through-substrate connections. Because the VIB wiring is built laterally, critical dimensions of ≤ 20μm with non-rectilinear patterns are feasible. Fabricated VIBs will be highlighted in the paper.

Progress on SHIELD USA’s molded fan-out core developments will be summarized in the paper. The molded fan-out core serves as a functional core for the substrate enabled by the embedding of capacitors, inductors, dies, and VIBs. Fabricated molded fan-out cores along with their electrical and thermo-mechanical characteristics will be highlighted in the paper. Exploration of embedding passive components into the substrate core with low-resistivity, thick Cu connections on both top and bottom surfaces will be discussed. Such embedded passive solutions along with power management and delivery ICs (e.g. voltage regulators) will enable a vertical power delivery solution fully embedded in the SHIELD USA substrate core.

Progress on the process engineering of ultra-high density planarized wiring layers (UHDPW) will be presented. We will describe Deca’s MDx™ process which is employed to achieve 2μm line and spacing with 5μm vias, while addressing the topography and coplanarity challenges. Unlike traditional photopolymer vias, MDx vias are defined by additively electroplated Cu vias in photoresist over each wiring layer. The vias are then encapsulated with a novel build-up film dielectric, developed by SHIELD USA’s partner Rogers Corporation, and planarized to reveal. Since these vias are defined by photoresist with high resolution and excellent sidewalls, capture pads are not required, significantly increasing routing density. The planarized structure also allows via stacking without inherent process limitations. Fabricated UHDPW wiring will be highlighted in the paper.

The paper will also cover SHIELD USA team progress on design automation efforts to ensure design accuracy, manufacturing robustness and reliability. Our progress on enabling chip-design-like EDA software tools supporting comprehensive modeling workflows will be outlined including developments on process design kits (PDK), parasitic extraction, electrical and thermomechanical modeling. Deca’s Adaptive Patterning® and Adaptive Defect Mitigation technologies will be outlined.

Finally, the commercial viability and the key applications for the SHIELD USA molded core substrates will be put forward with a focus on artificial intelligence (AI), high-performance computing (HPC), networking, and advanced driver assistance systems (ADAS) applications.