Package Design & Layout Engineer

Cspeed IO is a stealth start up 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.

Cspeed IO 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

You will own the physical design of our optical engine packages — redistribution layers, substrate, and the bump and ball maps that tie the die stack to the host board. This is a hands-on layout role with real architectural influence.

You will work between our PIC and EIC design teams, our SI/PI and thermal engineers, and our supply chain (wafer fab, substrate vendor, OSAT). You will not be handed a finished floorplan to route — you will help define it.

What You'll Do

Layout execution

• Deliver RDL/UBM and package substrate layouts for our optical engine products and test vehicles, from floorplan through tape-out.
• Define and release bump maps, ball maps, and escape routing strategies for multi-die assemblies (PIC, EIC, and light source die).
• Design to 200G/lane-class electrical requirements: differential pair routing, reference-plane integrity, crosstalk isolation, and power delivery for high-current, low-noise rails.

Co-design and floor planning

• Participate from concept phase: produce preliminary floorplans and stack-up proposals that reconcile electrical, optical, thermal, and mechanical constraints before they are frozen.
• Iterate with SI/PI engineers on test routes to converge routing topologies and design rules.

Design rules, DFM, and supplier engagement

• Work directly with wafer fabs, substrate suppliers, and OSATs to capture and negotiate design rules, stack-ups, and assembly constraints.
• Generate fab and assembly release packages; drive DFM/DFA closure and design reviews through to sign-off.
• Flag rule conflicts early and propose alternatives rather than routing around them silently.

Verification and automation

• Run and own physical verification: DRC, connectivity/LVS-style netlist checks, and cross-domain consistency between die, package, substrate, and board.
• Manage netlists for heterogeneous assemblies across revisions and product variants.
• Build scripted automation (SKILL, Python, or equivalent) for repetitive layout, checking, and release tasks.

Build support

• Support test vehicle definition, first builds, bring-up, failure analysis, and yield learning — including layout changes driven by assembly reality.

Required Qualifications

• BS or MS in Electrical Engineering, or equivalent practical background.
• 6+ years of IC package physical design, including at least one product taken from concept through tape-out and volume-relevant build.
• Expert-level proficiency in a package layout tool: Cadence Allegro Package Designer / APD+ / SiP, Siemens Xpedition Package Designer, Synopsys IC Package, or equivalent.
• Demonstrated experience with multi die packaging: 2D or 2.5/3D integration.
• Working fluency with multi-layer organic substrate construction and how material and stack-up choices constrain routing.
• Practical experience closing DFM/DFA with external substrate suppliers and OSATs.
• Comfortable working in English across a distributed team and multiple time zones.

Preferred Qualifications

• Demonstrated experience with advanced packaging: 2.5D/3D integration, RDL, TSV interposers, fan-out, microbump or Cu-pillar flip-chip.
• Layout for 112G/224G SerDes or comparable high-speed interfaces; familiarity with signal and power integrity workflows (e.g. Cadence Sigrity/PowerSI, Ansys).
• Familiarity with mask and RDL vendor flows, GDS-based layout environments (Virtuoso, KLayout), and AutoCAD file exchange.
• Experience with package/IC co-design environments (e.g. Cadence Integrity 3D-IC).
• Scripting for design automation and rule checking.
• Experience at a startup or on a first-of-its-kind product, where the design rules did not exist yet.

Why This Role Is Different

Most package layout roles are a step in someone else's flow. Here, the package is the product. You will be one of a handful of people who determine whether a next-generation optical engine is manufacturable, and you will see your layout decisions land in silicon and in an OSAT line within months, not years.