Method of hydrophobizing and patterning frontside surface of integrated circuit
View Patent ↗A method of hydrophobizing a frontside surface of an integrated circuit. The method includes the steps of: (a) depositing a hydrophobic polymeric layer onto the frontside surface; (b) depositing a protective metal film onto the hydrophobic polymeric layer; (c) depositing a sacrificial material onto the metal film; (d) patterning the sacrificial material; (e) etching through the metal film, the hydrophobic polymeric layer and the frontside surface; (f) performing MEMS processing steps on a backside of the integrated circuit; (g) subjecting the integrated circuit to an oxidizing plasma, wherein the metal film protects the hydrophobic polymeric layer from the oxidizing plasma; and (h) removing the protective metal film to provide an integrated circuit having a relatively hydrophobic patterned frontside surface.
1. A method of hydrophobizing a nozzle plate of a printhead integrated circuit, said method comprising the steps of:
(a) depositing a hydrophobic polymeric layer onto said nozzle plate;
(b) depositing a protective metal film onto said hydrophobic polymeric layer;
(c) depositing a sacrificial material onto said metal film;
(d) patterning said sacrificial material;
(e) etching through said metal film, said hydrophobic polymeric layer and said nozzle plate to define nozzle openings in said nozzle plate;
(f) performing MEMS processing steps on a backside of said printhead integrated circuit;
(g) subjecting said printhead integrated circuit to an oxidizing plasma, wherein said metal film protects said hydrophobic polymeric layer from said oxidizing plasma; and
(h) removing said protective metal film, thereby providing a printhead integrated circuit having a relatively hydrophobic nozzle plate with nozzle openings defined therein.
2. The method of claim 1 , wherein said protective metal film is comprised of a metal selected from the group consisting of: titanium and aluminium.
3. The method of claim 1 , wherein said protective metal film has a thickness in the range of 10 nm to 1000 nm.
4. The method of claim 1 , wherein said nozzle plate is comprised of a material selected from the group consisting of: silicon oxide, silicon nitride and silicon oxynitride.
5. The method of claim 1 , wherein step (e) is performed by sequential etching steps.
6. The method of claim 5 , wherein a first metal-etching step is followed immediately by a second etching step for removing the hydrophobic polymeric layer and nozzle plate material.
7. The method of claim 6 , wherein said second etching step is a dry etch employing a gas chemistry comprising O 2 and a fluorinated etching gas.
8. The method of claim 7 , wherein said fluorinated etching gas is selected from the group consisting of: CF 4 and SF 6 .
9. The method of claim 1 , wherein step (h) is performed by a wet rinse using peroxide or HF.
10. The method of claim 1 , wherein all plasma oxidizing steps are performed prior to removing said protective metal film in step (h).
11. The method of claim 1 , wherein step (g) removes any sacrificial material exposed to said oxidizing plasma.
12. The method of claim 1 , wherein all backside MEMS processing steps are performed prior to removing said protective metal film in step (h).
13. The method of claim 11 , wherein said printhead integrated circuit is a wafer, and wherein said backside MEMS processing steps include dicing the wafer into individual printhead integrated circuits.
14. The method of claim 1 , wherein said hydrophobic polymeric layer is comprised of a polymeric material selected from the group consisting of: polymerized siloxanes.
15. The method of claim 14 , wherein said polymeric material is polydimethylsiloxane.
16. The method of claim 1 , wherein said sacrificial material is photoresist.