Microfluidic device for continuous ejection of fluids, in particular for ink printing, and related manufacturing process

A method, comprising:

• forming a plurality of piezoelectric actuators on a surface of a first dielectric layer of a first semiconductor wafer;
• forming a first protective layer on the piezoelectric actuator and on the surface of the first dielectric layer;
• forming a second protective layer on the first protective layer;
• forming a plurality of supply channels adjacent to respective piezoelectric actuators of the plurality of piezoelectric actuators and extending through the first protective layer, the second protective layer, and the first dielectric layer of the first semiconductor wafer;
• forming a plurality of cavities in a second semiconductor wafer into a semiconductor layer of the second semiconductor wafer;
• forming a plurality of holes that extend into the second semiconductor wafer and entirely through the semiconductor layer of the second semiconductor wafer;
• overlapping each respective hole of the plurality of holes of the second semiconductor wafer with a corresponding supply channel of the plurality of supply channels of the first semiconductor wafer by coupling the second semiconductor wafer to the first semiconductor wafer;
• forming a plurality of chambers in the first semiconductor wafer in fluid communication with the plurality of supply channels of the first semiconductor wafer, wherein forming the plurality of chambers includes forming each respective chamber of the plurality of chambers to include:
• a first portion with a first diameter;
• a second portion with a second diameter greater than the first diameter;
• and
• a connecting portion extending from the first portion to the second portion, the connecting portion having a width substantially equal to the first diameter.

A method, comprising:

• forming a piezoelectric actuator on a first semiconductor wafer;
• forming a first protective layer on and covering the piezoelectric actuator;
• forming a second protective layer on and covering the first protective layer;
• forming a supply channel adjacent to the piezoelectric actuator and extending through the first protective layer, through the second protective layer, and into the first semiconductor wafer;
• forming a cavity extending into a semiconductor layer of a second semiconductor wafer;
• forming a hole extending into and entirely through the semiconductor layer of the second semiconductor wafer;
• overlapping the hole of the second semiconductor wafer with the supply channel of the first semiconductor wafer by coupling the second semiconductor wafer to the first semiconductor wafer;
• forming a chamber in the first semiconductor wafer in fluid communication with the supply channel of the first semiconductor wafer, forming the chamber in the first semiconductor wafer including:
• forming a first portion with a first diameter;
• forming a second portion with a second diameter greater than the first diameter;
• and
• forming a connecting portion extending from the first portion to the second portion, the connecting portion having a width substantially equal to the first diameter.