Signal & Power Integrity (SI/PI) Engineer - Advanced Packaging

Signal & Power Integrity (SI/PI) Engineer – Advanced Packaging

CScale is a startup backed by Sutter Hill Ventures and Atreides Capital - headquartered in Palo Alto, CA. Our executive team has a demonstrated track record of building and scaling category-defining semiconductor and infrastructure businesses at companies like Broadcom, Lumentum, Tesla, Apple, Samsung, Intel, and VMware.

CScale is developing next-generation optical semiconductor solutions for the AI infrastructure market, focused on enabling true “scale-up” architectures. Our mission is to replace traditional copper interconnects with advanced fiber-optic technologies that overcome the limitations of existing optics solutions and architectures.

The Role

This position owns the electrical performance of CspeedIO optical engine packages across three areas: signal integrity between the electronic IC and the photonic dies inside the package; signal integrity across the channel between the CspeedIO package and the host ASIC; and power integrity for the package as a whole. This role defines the modeling and measurement approach as much as it applies one.

You will drive the electrical definition of the package architecture rather than validate a design handed to you after floorplan freeze.

Responsibilities

3D EM modeling and correlation

• Perform 3D EM design and simulation of high-speed interconnects.
• Model and characterize in-package interconnect between the electronic IC and the photonic dies, including transition structures.
• Develop and validate test vehicles to characterize next-generation PCB materials, packages, and interconnects.
• Conduct S-parameter and time-domain measurement to extract channel performance and correlate against simulation.

Channel architecture and standards compliance

• Perform link-level analysis against advanced high-speed standards, and design package substrate stackups, via structures, breakout regions, and connector transitions to meet IEEE, CEI, and MSA compliance.
• Define routing constraints, reference plane design, and return path continuity to hold signal degradation within budget.
• Design and optimize PDNs to meet target impedance, minimize noise coupling, and support fast transient loads for high-speed DSPs and ICs.

Design collaboration and bring-up

• Work with CMOS design, optical, and packaging teams to converge stack-up, breakout, and routing strategy for high-density designs without sacrificing manufacturability or reliability.
• Provide SI/PI layout guidelines to package substrate designers, and review placement and routing on high-speed paths and power domains before release.
• Support bring-up and validation.

Required Qualifications

• BS or higher in Electrical Engineering, Applied Physics, or a related field, with emphasis on electromagnetics, signal integrity, power integrity, or high-speed digital design.
• 7+ years of package-level SI/PI analysis experience on high-speed interconnects in optical, networking, or high-performance hardware systems.
• Hands-on proficiency with 2.5D/3D EM solvers: Ansys HFSS, SiWave, Cadence Sigrity, CST, or Keysight ADS.
• Command of signal integrity fundamentals, including S-parameter analysis and channel modeling.
• High-speed differential signal integrity at 224G or similar.
• Working knowledge of PCB and package substrate stackup design, via modeling, impedance control, and crosstalk mitigation.
• Working knowledge of power delivery design: decoupling strategy, PDN impedance analysis, and noise mitigation.

Preferred Qualifications

• Co-packaged optics or interposer-structure package experience.
• Custom model and workflow development for EM simulation or measurement automation.
• 2.5D/3D package architecture experience extending beyond interconnect-level SI/PI.