System for maintaining a controlled atmosphere in an electronic circuit package

A system for maintaining electronic components, such as integrated circuit chips, in a contaminant-free controlled atmosphere is disclosed. The components, which may be mounted on a multichip module, are housed in a sealed enclosure and a positive pressure of contaminant-free gas, such as pure nitrogen, is maintained within the enclosure. A source of pressurized gas, controllably connected to the enclosure is provided and, preferably, an exhaust valve is used to equalize the pressure in the enclosure when it is necessary to access the interior for purposes of maintenance or repair. Preferably, there is a control system which monitors and maintains the proper level of pressure within the enclosure and which may be used to periodically flush the enclosure. Also preferably, one or more canisters of getter material are attached to the enclosure for removing contaminants.