Test Engineer
Engineers who develop the tests, run on automatic test equipment (ATE), that check whether chips work to specification at wafer level and after packaging, balancing quality against test cost.
What the job involves
Test engineers create the tests that check whether manufactured chips work to specification and make them ready for volume production. Testing is generally split into wafer test, done on the wafer before dicing, and final test, done after the chips are assembled into packages. They develop test programs that run on ATE (automatic test equipment), defining what to measure, such as voltages, currents, timing and functions, and the pass/fail limits. The real skill lies in reliably catching defective parts while shortening test time per chip to keep costs down. After volume production starts, they keep analyzing test results and improving the tests.
Who they work with and what they handle
What can be tested is decided by the chip's design, so they work with circuit designers from an early stage, especially those responsible for DFT (design for testability). Test results are also used for yield analysis, so they work with yield and quality engineers too. What they handle: the ATE, probe cards that touch needles to the pads on the wafer, fixtures and boards that connect the chip to the ATE, test programs, and large volumes of test result data. Besides in-house test operations, they may work with an OSAT that provides test services to bring a product into volume production.
Knowledge and skills
You need the fundamentals of both digital and analog circuits. On the digital side, it helps to understand scan test, ATPG (automatic test pattern generation) and fault coverage; on the analog side, how to measure the characteristics of op-amps and ADCs. Programming skills for writing test programs, the ability to read datasheet specifications precisely, and the ability to spot measurement error and noise are also required. Test escapes lead to failures in the field while excessive testing raises cost, so the perspective of balancing the two is essential.
Where to start
Start with the “Testing and inspection” field to cover the basics of wafer test, burn-in, scan test and so on. To understand what you are testing, study “Logic circuits”, “Analog and electronic circuits” and “A/D and D/A conversion”; you will see which parameters are measured and why. How to read specifications is in “How to read datasheets”, and how test results are used is in “Yield and quality control”. Among the courses, “Back end, quality and safety” and “Circuits, design and memory” are recommended.
Fields to learn
Testing and inspection 51 questions Logic circuits 50 questions Analog and electronic circuits 50 questions A/D and D/A conversion 50 questions How to read datasheets 50 questions Yield and quality control 50 questions
10 starter questions for this role
Ten basic questions from the fields this role uses
Recommended courses
Back end, quality and safetyLearn what it takes to deliver chips as products: packaging and advanced packaging, testing, reliability, environment and safety, and industry trends.Circuits, design and memoryLearn what goes inside a chip and how it is designed: logic and analog circuits, AD/DA conversion, CPUs, memories and the design flow.
Key terms
ATE (automatic test equipment) Wafer test (probe test) Probe card DFT (design for testability) Scan test ATPG (automatic test pattern generation) Stuck-at fault Fault coverage BIST (built-in self-test) IDDQ test Burn-in KGD (known good die)
FAQ
Can I become a test engineer without a technical background or industry experience?
This role uses both circuit knowledge and programming, so in general people with electrical, electronics or computing knowledge tend to be the main candidates. Software development experience can be useful for developing test programs. Hiring requirements differ by company and change over time, but learning circuit basics and how testing works will help you understand the job faster.
How is it different from a design verification engineer?
Verification engineers check, before manufacturing, that the design itself meets the specification, mainly through simulation. Test engineers use equipment to check each manufactured chip for defects introduced during manufacturing. Put simply, the first finds design errors and the second finds manufacturing defects.
Do I need any license or certification?
In general, no specific license or certification is required to become a test engineer. In practice, understanding circuits, programming skills for writing test programs and the ability to analyze data and turn it into improvements count most. The ATE and programming environment differ by workplace and are usually learned on the job.