Method of fabricating printhead having hydrophobic ink ejection face
View Patent ↗A method of fabricating a printhead having a hydrophobic ink ejection face is provided. The method comprises the steps of: (a) providing a partially-fabricated printhead comprising a plurality of nozzle chambers and a relatively hydrophilic nozzle surface, the nozzle surface at least partially defining the ink ejection face; (b) depositing a layer of relatively hydrophobic polymeric material onto the nozzle surface, the polymeric material being resistant to removal by ashing; and (c) defining a plurality of nozzle openings in the nozzle surface, thereby providing a printhead having a relatively hydrophobic ink ejection face. Steps (b) and (c) may be performed in any order.
1. A method of fabricating a printhead having a hydrophobic ink ejection face, the method comprising the steps of:
(a) providing a partially-fabricated printhead comprising a plurality of nozzle chambers filled with sacrificial material and a relatively hydrophilic nozzle surface, said nozzle surface at least partially defining the ink ejection face;
(b) depositing a layer of relatively hydrophobic polymeric material onto the nozzle surface;
(c) defining a plurality of nozzle openings in said nozzle surface by the sub-steps of;
(c 1 ) depositing a photoresist mask on said polymeric material;
(c 2 ) patterning said photoresist mask so as to unmask said polymeric material in a plurality of nozzle opening regions;
(c 3 ) etching said unmasked polymeric material and said underlying nozzle surface to define the plurality of nozzle openings; and
(d) removing said sacrificial material and said photoresist mask by ashing in an oxidative plasma, said polymeric material being resistant to removal by said oxidative plasma,
thereby providing a printhead having a relatively hydrophobic ink ejection face,
wherein said polymeric material is selected from the group consisting of: polymerized siloxanes.
2. The method of claim 1 , wherein, in said partially-fabricated printhead, a roof of each nozzle chamber is supported by a sacrificial photoresist scaffold, said method further comprising the step of removing said photoresist scaffold by ashing.
3. The method of claim 1 , wherein said polymeric material is polydimethylsiloxane (PDMS).
4. The method of claim 1 , wherein at least some of said polymeric material is UV-cured after deposition.
5. The method of claim 1 , wherein a same gas chemistry is used to etch said polymeric material and said nozzle surface.
6. The method of claim 5 , wherein said gas chemistry comprises O 2 and a fluorine-containing compound.
7. The method of claim 1 , wherein a roof of each nozzle chamber is defined at least partially by said nozzle surface.
8. The method of claim 7 , wherein said nozzle surface is spaced apart from a substrate, such that sidewalls of each nozzle chamber extend between said nozzle surface and said substrate.
9. The method of claim 1 , wherein a roof and sidewalls of each nozzle chamber are comprised of a ceramic material depositable by CVD.
10. The method of claim 9 , wherein said roof and sidewalls are comprised of a material selected from the group comprising: silicon oxide, silicon nitride and silicon oxynitride.
11. The method of claim 1 , wherein said hydrophobic polymeric material forms a passivating surface oxide in said oxidative plasma.
12. The method of claim 11 , wherein said hydrophobic polymeric material recovers its hydrophobicity after being subjected to said oxidative plasma.