High Temperature Protection against Unwanted Species within Hermetic Packaging

Abstract

The need for electronic applications to be able to withstand high temperatures has become more prevalent in recent years. With drilling in the oil and gas industry getting deeper, the operating temperatures are getting higher, with typical geothermal gradients of 25 °C/km. Temperatures up to 250 °C are often seen by drilling operations, which is putting a greater strain on the electronics and associated packaging. Standard methods of cooling are not viable for these harsh environments, so new technology is required to negate the effects of the extreme temperatures. As well as the use of high temperature stable electronic components, High Temperature Getters are required to remove gaseous contaminants from electronic housings to negate the associated deleterious effect on performance. The contaminating species to be removed are commonly H2O, CO2, and H2, and sometimes short chain organic molecules. Conventional getter materials can remove damaging species at temperatures up to about 80 °C. New technology is however required to eliminate these species at temperatures up to 250 °C, where existing getter formulations would certainly fail. Johnson Matthey has developed a range of getters that can remove multiple contaminants at both ambient and elevated temperatures. The first product in the series, HTA 1 can remove water and carbon dioxide. Addition of a metal oxide component in HTA 2 facilitates hydrogen removal at elevated temperatures, with capacities in excess of 70 cm3/g achieved. HTA 3 can adsorb unwanted organic contaminants in addition to removing water and carbon dioxide. HTA 4 is a combined getter capable of eliminating all of the aforementioned contaminant species. These products, combined with the unique, precision engineered Hi-Rel encapsulation (Figure 1) allow getters to be supplied pre-activated, without the end user needing to apply a thermal treatment prior to use. The product can be fitted into any hermetic device to extend the lifetime, thus decreasing the number of failures within electronic assemblies, improving system reliability and preventing operations being shut down as frequently.