Package Mechanical FEA Engineer

CspeedIO is a stealth 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.

CspeedIO 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 structural finite element analysis for CspeedIO optical engine packages: warpage prediction through the assembly process, stress in bump and interconnect structures, and the lifetime models supporting qualification.

Responsibilities

Warpage and process simulation

• Predict warpage at each stage of the assembly process — bonding, reflow, underfill cure, encapsulation, lid attach, singulation
• Own the flatness, coplanarity, and facet planarity budgets that assembly and optical coupling depend on.

Interconnect stress and reliability

• Analyze stress and strain in micro-bump, copper pillar, C4, and second-level interconnect structures, including chip-package interaction and low-k dielectric risk.
• Own solder and interconnect fatigue life prediction, and model thermal cycling, shock, drop, and board-level reliability against JEDEC and IPC methodology.
• Quantify stress in the photonic IC and its consequences for optical performance, in partnership with the photonic design team.

Methodology, correlation, and design influence

• Define simulation methodology and modeling standards with documented, auditable assumptions, and correlate predictions against measured warpage, cross-section, and reliability data.
• Provide design guidance and sign-off criteria during architecture definition — stack-up, thickness, bump pitch, underfill and stiffener selection — rather than after design freeze.
• Engage substrate suppliers and OSATs on process assumptions, measured warpage data, and material characterization.

Required Qualifications

• MS or PhD in Mechanical Engineering, Materials Science, Engineering Mechanics, or equivalent practical background.
• 6+ years of structural FEA for semiconductor packaging, including warpage and interconnect stress analysis on a product carried into build.
• Deep hands-on capability in Ansys Mechanical, Abaqus, or equivalent, including nonlinear material modeling.
• Command of nonlinear and time-dependent material behavior — creep, viscoplasticity, viscoelasticity, fatigue — with correct treatment of temperature and rate dependence.
• Working knowledge of solder constitutive models and fatigue life prediction methods.
• Demonstrated correlation against physical measurement, and the judgment to distinguish a modeling error from a process excursion.

Preferred Qualifications

• Chip-package interaction analysis including back-end-of-line and low-k dielectric stress.
• Board-level reliability and PCB-to-package interaction modeling; JEDEC and IPC qualification methodology.
• Photonic or optoelectronic packaging, particularly warpage as an optical alignment constraint or stress effects on optical behavior.
• Coupled thermal-structural workflows, including transfer of a computed temperature field into a structural model.
• Design of experiments and surrogate modeling to compress large parametric studies.