Hermetically sealed electronics module with enhanced cooling of core integrated circuit

A hermetically sealed electronics module, comprising:

• an interconnecting substrate;
• a core integrated circuit (IC) installed on the substrate;
• a collar having a bottom edge hermetically bonded to the substrate, said collar being configured such that it surrounds and encircles the core IC;
• a lid hermetically sealed to a top edge of the collar, the lid, collar, and substrate together forming and enclosing a hermetically sealed chamber that contains the core IC;
• a heat spreader bonded to an inward-facing surface of the lid and positioned within the hermetically sealed chamber over the core IC, the heat spreader extending downward from the lid into proximal, thermal contact with an upper surface of the core IC;
• a tall component installed on the interconnecting substrate within the hermetically sealed chamber, the tall component extending upward from the substrate to a height that is greater than a height of the upper surface of the core IC, the heat spreader being configured such that it does not overlap the tall component, and such that it extends downward below the height of the tall component;
• wherein a plurality of core ICs are installed on the interconnecting substrate within the hermetically sealed chamber;
• wherein the heat spreader is positioned within the hermetically sealed chamber over all of the core ICs;
• wherein the heat spreader extends downward from the lid into proximal, thermal contact with upper surfaces of all of the core ICs;
• and
• wherein at least two of the core ICs differ in height, and wherein a thickness of the heat spreader is non-uniform, and is varied so as to be proximal to the upper surfaces of the core ICs according to their heights.