Reliability Engineer
Engineers who verify and assure that products keep working without failure over their service life, using accelerated stress tests and analysis of failure mechanisms.
What the job involves
Reliability engineers confirm that semiconductor products keep working without failure over their intended service life and operating environment. Since you cannot wait for the real service life to pass, they run accelerated tests that speed up degradation with higher temperature, voltage or humidity. Typical tests include HTOL (high-temperature operating life), THB (temperature-humidity-bias), HAST (highly accelerated stress test) and temperature cycling. They plan these tests and take part in qualification, the decision on whether a product can go into volume production and ship based on the results. When failures occur, they analyze the mechanism and feed it back into design or process improvements.
Who they work with and what they handle
Degradation can originate in the transistors, the wiring or the package, so they work with device engineers, process engineers, packaging engineers and circuit designers. When customers request reliability data or a problem occurs in the field, they may also respond together with quality assurance. What they handle: environmental chambers and test boards, test standards, analysis results for failed samples, and lifetime data with its statistical analysis. Test conditions are often based on industry standards such as JEDEC standards and, for automotive products, AEC-Q100.
Knowledge and skills
Understanding failure mechanisms is at the core. Examples include electromigration, in which metal atoms in the wiring are moved by current; TDDB (time-dependent dielectric breakdown), in which the gate dielectric breaks down over time; NBTI and hot carrier injection (HCI), which shift the threshold voltage; and package failures caused by thermal strain. To translate accelerated test results to real use conditions, you need to be fluent with acceleration models such as the Arrhenius model and lifetime statistics such as the Weibull distribution. Reading standards precisely and recording and explaining conditions and results carefully is also expected.
Where to start
Start with the “Reliability” field to learn the bathtub curve, how failure rates are expressed, the main failure mechanisms and the idea behind accelerated testing. If you will handle automotive products, “Automotive Semiconductors and Functional Safety” covers their quality requirements and standards. Because most failures occur in transistors, wiring or packages, also studying “MOSFET”, “Interconnect processes” and “Packaging and assembly” lets you reason about causes from the structure. The “Back end, quality and safety” course gives the overall picture from the back end through quality.
Fields to learn
Reliability 51 questions Automotive Semiconductors and Functional Safety 50 questions Packaging and assembly 50 questions MOSFET 50 questions Interconnect processes 51 questions Yield and quality control 50 questions
10 starter questions for this role
Ten basic questions from the fields this role uses
Recommended courses
Key terms
HTOL (high-temperature operating life test) THB (temperature-humidity-bias test) HAST (highly accelerated stress test) Temperature cycling Bathtub curve Arrhenius model Weibull distribution FIT rate Electromigration TDDB (time-dependent dielectric breakdown) NBTI (negative bias temperature instability) AEC-Q100
FAQ
Can I become a reliability engineer without a science or engineering background?
Because you need to understand failure mechanisms physically, in general a background in electrical engineering, physics, materials or mechanical engineering is useful for this role. On the other hand, test planning, statistical analysis and standards-based management have a lot in common with reliability and quality work in other industries. Hiring requirements differ by company and change over time.
How is it different from a yield and quality engineer?
Yield and quality engineers focus on reducing parts that are already defective when they are made. Reliability engineers deal with whether parts that were good when shipped will fail during use. Both use failure analysis and statistics, but it helps to think of the difference as the time scale each one covers.
Do I need any license or certification?
In general, no specific license or certification is required. Some people use certificates in reliability engineering or quality control as study aids, but how much they count in hiring differs by company. In practice, understanding failure mechanisms, reading test standards correctly and judging results statistically count most.