Method of protecting micropackages from their environment

A method for protecting active and passive electronic components mounted within a given component area of one substantially planar surface of a multilayer substrate from the ambient environment, said component area having a perimeter, said method comprising the steps of:

• a. cutting a segment of a thin membrane made of a material substantially nonpermeable to water vapor to a size that substantially covers the area of the substrate on which the components are mounted, said segment having a perimeter that substantially coincides with the perimeter of the component area of the substrate and having an inner and an outer surface;
• b. attaching the perimeter of the segment to the substrate substantially at the perimeter of the component area with a sealant adhesive;
• c. coating the outer surface of the membrane with a layer of a sealant adhesive having a thickness substantially greater than the thickness of the membrane, said layer of sealant adhesive adhering to the outer surface of the membrane and to the sealant adhesive;
• d. forming a small opening through the layer and the segment;
• e. subjecting the substrate to substantially reduced atmospheric pressure substantially in the range of one inch of mercury;
• and,
• f. sealing the opening formed through the layer and the segment with a sealant adhesive while the substrate is subjected to such substantially reduced atmosphere.

A method for protecting a plurality of large scale integrated circuit chips and passive electronic components mounted within a component area on a substantially planar surface of a multilayer substrate from the ambient environment, said component area having a perimeter, said method comprising the steps of:

• a. securing a vertical riser to the perimeter, said riser having an inner wall;
• b. forming a segment of a thin nonpermeable nonadherable membrane to a shape that substantially covers the component area of the substrate and the components mounted on the substrate in the component area, said membrane having a perimeter that substantially contacts the inner wall of the riser, said segment having an inner and outer surface;
• c. attaching the perimeter of the segment to the inner wall of the riser with a bead of room temperature vulcanizing silicone adhesive sealant;
• d. coating the outer surface of the segment with a substantial layer of substantially impermeable silicone adhesive sealant which is substantially thicker than the membrane of said segment and which adheres to the outer surface of the segment and to the bead of sealant adhesive;
• e. forming an opening through the coating and the segment;
• f. placing the substrate in a chamber and substantially reducing the atmospheric pressure in the chamber;
• and
• g. sealing the opening formed through outer layer and the segment with a room temperature vulcanizing silicone adhesive sealant while the substrate remains in the chamber at such a reduced atmospheric pressure.