Patent ID: 6949201

Claim:
Process for manufacturing a thermal ink jet printhead comprising a tank suitable for containing ink, comprising steps of: providing a wafer comprising a plurality of dice, each of which includes a substrate and a plurality of resistors, said dice having an upper face and a lower face; making elementary blind holes through said upper face, in correspondence with each of said resistors; etching a first part of a groove in said substrate on said lower face of each of said dice, said groove being intended for conveying said ink of said tank; applying a first layer of positive photoresist on said upper face of each of said dice, and obtaining a plurality of cavities on said first layer of positive photoresist, each of said cavities being in correspondence with each of said resistors and having a shape that covers the corresponding resistor and at least one of said elementary holes; depositing a plurality of sacrificial layers inside each of said cavities; applying a second layer of positive photoresist on said upper face of each of said dice and on said sacrificial layers; producing from said second layer of positive photoresist a plurality of casts, each of said casts being adherent to each of said sacrificial layers and having an outer face; applying a structural layer on said upper face of each of said dice, on said sacrificial layers and on said casts, said structural layer having an outer surface co-planar with said outer face of said casts; etching a second part of said groove in said substrate on said lower face of each of said dice, until said elementary holes are reached and rendered through-holes; removing said positive photoresist from said elementary holes—separating said dice; removing said casts; and removing said sacrificial layers.