X‑Ray Assisted Device Alteration for 3DIC with Gate‑All‑Around Transistors, Backside Power Delivery Networks, and Advanced Packaging
X‑Ray Assisted Device Alteration for 3DIC with Gate‑All‑Around Transistors, Backside Power Delivery Networks, and Advanced Packaging
Wednesday, October 7, 2026: 9:00 AM
Summary:
Three‑dimensional (3D) integration with gate‑all‑around (GAA) transistors, backside power delivery networks (BSPDNs), and advanced packaging is rapidly reducing the effectiveness of conventional optical fault‑isolation techniques such as laser‑assisted device alteration (LADA) and thermal‑assisted device alteration (TADA), as backside metallization, buried power structures, and stacked dies severely limit near‑infrared access to active devices. X‑ray assisted device alteration (XADA) provides an alternative by using focused X‑ray beams to perturb deeply buried circuitry, but its behavior in modern GAA technologies and BSPDN‑enabled 3DICs has not been fully characterized. This work extends earlier feasibility demonstrations of XADA by systematically investigating X‑ray induced perturbations across device, circuit, and chip levels: we interpret the response in terms of total‑ionizing‑dose behavior, showing cumulative timing slow‑down in ring oscillators and spatially isolated inverter/NMOS/PMOS structures, demonstrate that the effective XADA interaction region scales with X‑ray beam size down to a few micrometers, and show that focused X‑rays can perturb a functional base die through a realistic 3DIC stack with increased dwell time required to achieve comparable circuit response. Additional BSPDN‑enabled speed‑path experiments show that XADA can also be applied to timing‑related failures. Building on these studies, we present a detailed XADA case on an advanced chip design with GAAFET devices and BSPDNs: using a ~1.6 µm focused X‑ray beam, raster scans with 1 µm and 0.25 µm spatial sampling, and gradient‑based analysis, we localize a scan‑chain defect to specific scan cells with submicron spot size and confirm the result with static XADA measurements and correlation to TADA hotspots. To our knowledge, this is the first demonstration of static XADA on a complex advanced GAA node die with backside power delivery, establishing XADA as a viable and scalable fault‑isolation technique for next‑generation 3DIC technologies.
Three‑dimensional (3D) integration with gate‑all‑around (GAA) transistors, backside power delivery networks (BSPDNs), and advanced packaging is rapidly reducing the effectiveness of conventional optical fault‑isolation techniques such as laser‑assisted device alteration (LADA) and thermal‑assisted device alteration (TADA), as backside metallization, buried power structures, and stacked dies severely limit near‑infrared access to active devices. X‑ray assisted device alteration (XADA) provides an alternative by using focused X‑ray beams to perturb deeply buried circuitry, but its behavior in modern GAA technologies and BSPDN‑enabled 3DICs has not been fully characterized. This work extends earlier feasibility demonstrations of XADA by systematically investigating X‑ray induced perturbations across device, circuit, and chip levels: we interpret the response in terms of total‑ionizing‑dose behavior, showing cumulative timing slow‑down in ring oscillators and spatially isolated inverter/NMOS/PMOS structures, demonstrate that the effective XADA interaction region scales with X‑ray beam size down to a few micrometers, and show that focused X‑rays can perturb a functional base die through a realistic 3DIC stack with increased dwell time required to achieve comparable circuit response. Additional BSPDN‑enabled speed‑path experiments show that XADA can also be applied to timing‑related failures. Building on these studies, we present a detailed XADA case on an advanced chip design with GAAFET devices and BSPDNs: using a ~1.6 µm focused X‑ray beam, raster scans with 1 µm and 0.25 µm spatial sampling, and gradient‑based analysis, we localize a scan‑chain defect to specific scan cells with submicron spot size and confirm the result with static XADA measurements and correlation to TADA hotspots. To our knowledge, this is the first demonstration of static XADA on a complex advanced GAA node die with backside power delivery, establishing XADA as a viable and scalable fault‑isolation technique for next‑generation 3DIC technologies.