Compact high density interconnect structure

An electronic system comprising:

• a plurality of segments, each of said segments comprising:
• a substrate having a perimeter and first and second sides having first and second major surfaces, respectively, and a plurality of feedthrough conductors extending through said substrate, each of said feedthrough conductors having first and second ends associated respectively with said first and second sides of said substrate.
• an electronic component having contact pads on a contact surface thereof, said electronic component being disposed with its contact surface in substantially the plane of said first major substrate surface, and
• a high density interconnect structure bonded to said electronic component and said first major surface of said substrate, said high density interconnect structure including dielectric material and a pattern of conductors disposed on or in said dielectric material, said pattern of conductors including conductors electrically connected to said contact pads of said electronic component and conductors electrically connected to said feedthrough conductors;
• said segments being arranged in a stack, said stack comprising:
• means for electrically connecting conductors of different, adjacent ones of said segments to each other at adjacent surfaces of said adjacent segments, said means for electrically connecting being disposed within the perimeters of both of said adjacent substrates, and
• a base segment having a given substrate size and a stack segment having a smaller substrate, said base segment having a seal ring on said first major surface thereof;
• and
• a sidewall sealed to said seal ring for enclosing said stack substrate in an enclosure comprising said substrate of said base segment and said sidewall.