Introduction to HTOL

HTOL (High Temperature Operating Life) testing is a stress test defined by JEDEC to define the reliability of IC products, and is an essential part of ASIC qualification tests. This post provides a high-level overview of HTOL test. Obviously, you should refer to the standard if you plan to perform HTOL JEDEC semiconductor testing.

HTOL meaning is High Temperature Operating Life and it s a semiconductor test that indicated the reliability of the semiconductor device. HTOL test is used to determine device resistance to continued operating stress, both electrical and thermal.

To predict reliability and operating life of IC products, JEDEC has defined a stress test that exposes the IC to extreme temperature conditions. Test results are then used to predict the long term failure rate of the IC. Almost every ASIC that is going to production must go thought HTOL testing.

HTOL reliability test is performed in an oven with 125C degrees, while the ICs are activated with dynamic signals and the VCC pins with max voltage. The HTOL test conditions are specified in the following table.

JEDEC Standard	JESD22-108, JESDS85
Name	HTOL
Temperature	T>=125C
VCC	VCC>=VCCmax
No. of Lots	3
No. Devices per Lot	77
Duration	1000 hours
Accept criteria	0 fails

After the HTOL stress test is completed the ICs must go through electrical screening to determine how many devices passed or failed the stress test. The JEDEC requirements define zero failures as an acceptable criterion, with test results defined in terms of FITs (failures in time). One FIT symbolizes one failure in 109 device hours.

To perform the HTOL test, all ICs must be in an oven, ideally placed in sockets and located on a HTOL board. Both sockets and burn-in-board must be able to withstand the high temperature during the test.