High reliability desiccant package designs with controlled moisture ingress rates for use in low particulate environments

摘要

The use of desiccants to maintain low humidity environments in closed systems is a common practice. Commercial desiccants typically use certain types of large surface area oxide media to serve as the water adsorption members. In general, these oxide materials are brittle and are prone to generate dust particles. These oxide media are often enclosed in housings ranging from plastic envelopes to perforated metal canisters. For some high reliability applications, conventional desiccant packaging may not be suitable. The potential release of fine desiccant particles could compromise the clean environment required for the assembly of high relability systems. The rate of the moisture adsorbed by the desiccant material during the system assembly operation in factory is another concern in an open environment. Common desiccant materials, such as silica gel and molecular sieves, can adsorb water rapidly; about 50