As demands for quality, safety, and reliability in automotive systems increases, auto makers and tier 1 suppliers turn to new IC testing technologies.
The safety-critical systems in cars are only as good as the integrated circuits (IC) in the system. The ICs must be of automotive-grade, meaning that they meet tough standards for quality, safety, and reliability. How do you ensure that the ICs are free of defects that can affect reliability through the life of the automobile? That answer is complex, but one critical factor is high-quality testing of the circuits after they are manufactured and throughout the operational life of the IC in the system.
What kind of testing ensures the levels of quality, safety, and reliability required for ICs in safety-critical automotive systems? First, the ICs are tested after being manufactured. The IC is connected physically to a specialized tester (via a probe or cable) that sends stimuli through dedicated test circuitry. The responses to those stimuli indicate potential chip defects that could lead to failures. The test circuitry on the chip and the software that generates test patterns come from EDA providers like Mentor, a Siemens Business.
For automotive applications, the goal is zero defects. Getting there isn’t always easy, and often includes deploying more and/or better test patterns and using big-data techniques to find and fix the underlying causes of defects in early versions of the chips.
How can you verify the IC continues to correctly function after it’s operating the car? All the electronic systems need to be tested throughout their lifetime of operation in the vehicle. Every time you turn on the ignition, the car systems go through a power-on-self-test, right down to checking the ICs in the systems. This is done through a technology called built-in-self-test (BIST). BIST is fast and does not require external testers, which has led to it also being used along with traditional test at the manufacturing stage to control test cost.
The new quality, safety, and reliability requirements for safety-critical automotive ICs – plus the pressures of competing in the fastest growing IC market – requires some adjustments to traditional IC test strategies. Mentor, a Siemens business, has been a leader in semiconductor test for many years and now offers new test software that allows the makers of automotive ICs to develop the most reliable products for the era of fully-autonomous driving. That’s why the world’s leading suppliers of ICs for automotive applications use Mentor’s Tessent DFT (design for test) and yield tools.
Our latest innovation for in-system testing for automotive ICs is called Tessent MissionMode. It is both software and hardware (in the form of a finite state machine that is added to the IC). Tessent MissionMode is notable for two reasons:
- It is the first commercial automated solution that enables ICs in the vehicle’s electronic systems to easily communicate errors to the main controller, which can warn drivers, send data to service centers, or execute self-repair.
- It allows, for the first time, continuous testing in the system ICs during operation, not just test at power-on.
How does it work? An on-chip controller sends messages (test patterns) to its assigned circuitry and uses the response to determine that it is functioning properly. If the controller gets an unexpected response, it sends the information to the MissionMode controller. This could be a simple pass/fail note, but the system can be configured to provide more detailed diagnostic information. For example, rather than just relaying that a particular memory chip failed, the BIST controller can specify the address and bit location of a failure. This information can be used to repair the memory on the fly by swapping in a spare memory element.
The MissionMode controller can also take direction from the car’s main engine control unit (ECU) to make repairs or obtain additional diagnostic information, including the source and type of error that occurred and where it occurred on the chip. This data helps service centers find the exact parts that need to be replaced, helps auto makers identify problem parts and adjust inventories, and helps the semiconductor companies or foundries fix the problem in subsequent batches of the chip and future designs.
The most successful and competitive semiconductor companies are using Mentor Tessent technology, including Tessent MissionMode, Tessent TestKompress with Cell-aware ATPG, and Tessent ScanPro with VersaPoint technology, to ensure the highest safety and reliability in ISO 26262 compliant ICs designed for use in automotive electronics. The Mentor Graphics Tessent family of silicon test and yield analysis tools are SGS-TUV Saar certified as standalone tools or in a tool-chain up to and including ASIL D for any tool confidence level (TCL).
To learn more, download this new whitepaper Tessent MissonMode: New Runtime DFT Technology Paves Way for Self-Correcting Automotive Electronics