Reliability Engineer, Advanced Packaging

CScale is building the interconnect for gigawatt-scale AI. As AI scale-up moves toward deployments spanning thousands of accelerators and dozens of racks, the network needs to deliver high bandwidth, predictable low latency, and continuous communication. CScale is building integrated optical interconnect designed for this new scale, enabling accelerators to work together like a single, much larger computer. But at this scale, performance is only part of the challenge. Optical failures are inevitable, and the system needs to keep running. CScale is designing the interconnect for continuity. Lasers will fail. Compute shouldn’t. The ambition is simple: Build AI interconnect you can take for granted. CScale came out of stealth in September 2026 with $145 million in Series C funding, bringing total funding to $188 million.

You will own package and assembly reliability for CScale's integrated optical engines: planning and running reliability tests on engineering and prototype builds, maturing the package qualification plan, driving testing through OSAT and test partners, commissioning failure analysis, and turning results into feedback the packaging and process teams can act on. This is a hands-on senior individual contributor role reporting to the head of reliability in Palo Alto, CA.

Responsibilities

Reliability testing

• Plan and run reliability testing on prototype and engineering builds, and get findings back to the packaging, process and optics teams quickly.
• Own and extend the package qualification plan: test selection, stress conditions, sample sizes and readouts, with a clear rationale for each cell.
• Organize and oversee reliability test cells, including fixtures, in-situ optical and electrical monitoring, calibration and data handling.
• Organize and oversee ongoing reliability testing (ORT)
• Decide which testing is outsourced to partners and which requires CScale's own capability, and help set up and run in-house testing where needed.

Partners and supplier quality

• Work directly with OSAT and test-partner engineers to execute testing, investigate reliability issues, and monitor process controls on the steps that matter for reliability.
• Select and manage reliability labs and failure analysis providers.
• Support process change notifications and define requalification scope.
• Support onboarding/qualification of new suppliers and partners, and transfer of development builds into production.

Failure analysis and corrective action

• Commission and direct failure analysis, and drive root cause to a physical mechanism.
• Own corrective-action closure with partners and suppliers, and verify that fixes work.
• Maintain a failure history so learning accumulates across builds.

Data and reporting

• Analyze life and stress data, apply appropriate acceleration models, and report results with stated confidence.
• Produce qualification reports and data packages.

Collaboration

• Work closely with the packaging/process team in Taiwan and in California. Coordinate with optics and test teams.
• Coordinate with the component reliability team so device- and package-level results form one consistent picture.

Required qualifications

• MS or PhD in materials science, mechanical engineering, electrical engineering, physics or a related field, or BS with equivalent experience.
• 5+ years in reliability engineering for semiconductor packaging, optoelectronic modules or advanced electronic assemblies.
• Experience qualifying packages to JEDEC and Telcordia reliability standards.
• Experience working directly with OSATs or assembly subcontractors.
• Experience commissioning and interpreting failure analysis on packaged devices.
• Working knowledge of reliability statistics and acceleration models.
• Business-fluent Mandarin and strong written and spoken English.

Preferred qualifications

• Reliability of 2.5D/3D and heterogeneously integrated packages (interposers, TSVs, fine-pitch flip-chip).
• Experience with package failure mechanisms such as solder fatigue, warpage, delamination and moisture-related failures.
• Experience with daisy-chain test vehicle design.
• Optoelectronic package reliability: optical alignment stability over temperature and life, fiber and connector attach.
• Experience with die-level reliability testing, including board design.
• Familiarity with thermomechanical simulation (FEA) for warpage and solder fatigue.
• Quality tools such as FMEA, control plans, SPC and DOE; JMP or Python for data analysis.
• Background in co-packaged optics, optical transceivers or datacenter interconnect.