Hollow-cavity flip-chip package with reinforced interconnects and process for making the same

An apparatus comprising:

• a substrate having an upper surface with a plurality of substrate I/O pads;
• a reinforcement layer over the upper surface of the substrate;
• a flip-chip die having a die body and a plurality of interconnects extending outward from a bottom surface of the die body, wherein each of the plurality of interconnects connects to a corresponding one of the plurality of substrate I/O pads through the reinforcement layer and at least one portion of the reinforcement layer encapsulates a first portion of each of the plurality of interconnects;
• an air cavity formed between the bottom surface of the die body and the upper surface of the substrate;
• and
• a protective layer extending over a top surface of the die body, down side surfaces of the die body, and toward the upper surface of the substrate to define a perimeter of the air cavity, wherein a second portion of each of the plurality of interconnects is exposed to the air cavity.