Reliable operation at -40°C to 125°C used to be considered high-rel. But auto makers want no worse than one defective part in a million components that are shipping at rates of more than a million per month. Thus, auto makers are demanding and getting more reliability than the military ever required.
To meet the old high-rel standards, chip makers depended on packaging and screening. Today, where using ordinary process technologies and packaging, the key lies in the design, including failure mode analysis.