Methods

Military testing standards were widely used initially. The military contracting market in significantly different from commercial manufacturers market. A noteworthy feature of today’s commercial marketing is very short market windows; products achieve success or failure in a year or less.  Active and ongoing competition amongst producers to provide and short market windows drives the need for cost-effective, time compression of defect discovery.

If your product is competing in today’s commercial competitive market, it has to use the fastest most cost-effective methods to find real data on the potential field reliability of the newest electronic materials and components. HALT is a process to improve competitiveness in a very short time.

It is nearly impossible to acquire timely and relevant field data on electronic assemblies by stressing them under worst-case design temperature specifications. Those temperatures are relatively benign compared to the strength of the materials.

In considering the thermal stress for components it is important to remember that in SMT re-flow processes, the entire circuit board with components is heated to greater than 183°C with temperature change rates of 120°C/minute and these process to not damage the components. Solder melting is not a relevant HALT failure and most HALT processes do not get even close to those temperatures. Most HALT procedures are limited to 130°C to 150°C, at the highest, unless it is a special use of electronics, which have to normally operate at those temperatures. Most average electronic assemblies can operate over 100°C for durations of time without damage or using a significant amount of life.