Senior SI/PI Engineer — 2.5D/3D Advanced Packaging

Excelon Solutions; Sunnyvale (CA); On-site; USD 150,000 - 190,000; Full time

Job summary

Excelon Solutions, Sunnyvale, CA, seeks an experienced SI/PI Engineer to advance signal and power integrity analysis for next-generation packaging, including 2.5D/3D architectures and high-bandwidth memory interfaces.

You will develop high-speed channel models, perform full-wave EM simulations, and optimize PDN from die to board, collaborating across IC, substrate, PCB, and thermal teams. Strong Python/MATLAB/Tcl scripting and lab measurement experience are required.

Qualifications

• 5+ years of experience in SI/PI analysis for semiconductor packaging or high-speed PCB design.
• Deep understanding of transmission line theory and S-parameter analysis.
• Experience with high-speed interface protocols (PCIe, UCIe, HBM, DDR, Ethernet SerDes).
• Proficiency in package stackup design, impedance control, and via transition optimization.
• Hands-on measurement correlation (VNA, TDR/TDT, oscilloscope).
• Programming/scripting in Python, MATLAB, Tcl for automation and post-processing.

Responsibilities

• Perform SI/PI analysis and design optimization for advanced silicon packages (CoWoS, EMIB, chiplet architectures).
• Develop and validate high-speed channel models for package interconnects (bumps, microbumps, TSVs, RDL, interposers).
• Run full-wave EM simulations to characterize S-parameters, crosstalk, impedance, and loss.
• Design and optimize PDN including decoupling, IR drop, and AC impedance from die to board.
• Conduct time-domain simulations (eye diagrams, BER) for PCIe Gen5/6, UCIe, HBM3/3E, DDR5, SerDes >112 Gbps.
• Collaborate with IC/package/PCB/thermal teams to co-optimize electrical performance.
• Develop and correlate simulation models with lab measurements (VNA, TDR, oscilloscope).
• Define SI/PI design guidelines for substrate stackup, routing, bumps/via assignments.
• Support DFM reviews with OSAT partners and substrate vendors.
• Investigate and resolve SI/PI-related failures during bring-up and validation.

Skills

SI/PI analysis

EM & circuit theory

Python

MATLAB

Tcl

S-parameter analysis

Transmission line theory

Tools

Ansys HFSS

Ansys SIwave

Cadence Clarity 3D

Keysight ADS Momentum

Synopsys HSPICE

Cadence Spectre

Keysight ADS

Ansys RedHawk

Cadence Voltus

Sigrity PowerDC/PowerSI

Job description

Excelon Solutions, Sunnyvale, CA, seeks an experienced SI/PI Engineer to advance signal and power integrity analysis for next-generation packaging, including 2.5D/3D architectures and high-bandwidth memory interfaces.

You will develop high-speed channel models, perform full-wave EM simulations, and optimize PDN from die to board, collaborating across IC, substrate, PCB, and thermal teams. Strong Python/MATLAB/Tcl scripting and lab measurement experience are required.