Microfluidic delivery system with a die on a rigid substrate

An electronic subsystem, comprising:

• a rigid support member having a first surface and a second surface opposite to the first surface, the rigid support member including:
• a plurality of contact pads on the first surface at a first end of the rigid support member;
• a first opening through the rigid support member at a second end of the rigid support member, the first opening exposing an interior surface of the rigid support member that extends from the first surface to the second surface of the rigid support member;
• and
• a layer of inert coating on the first surface of the rigid support member, the second surface of the rigid support member, and the interior surface of the rigid support member in the first opening;
• a fluid ejection die on the first surface of the rigid support member, the fluid ejection die including:
• a second opening aligned with the first opening through the rigid support member;
• and
• a plurality of nozzles coupled to the second opening.

An electronic subsystem, comprising:

• a printed circuit board having a first surface, a second surface opposite to the first surface, the printed circuit board including:
• a first opening through the printed circuit board that exposes an internal sidewall of the printed circuit board;
• and
• a liner layer on the first surface, the second surface, and on the internal sidewall of the printed circuit board;
• a microfluidic die on the first surface of the printed circuit board.