Methods of making inkjet print heads using a sacrificial substrate layer

1. A method of making a plurality of inkjet print heads comprising:

forming a first wafer comprising a sacrificial substrate layer, and a first dielectric layer thereon having a plurality of first openings therein defining a plurality of inkjet orifices;

forming a second wafer having a plurality of inkjet chambers defined thereon, the second wafer being formed physically independent of the first wafer;

joining the first and second wafers together, by bringing together the physically independently formed first and second wafers, so that each inkjet orifice is aligned with a respective inkjet chamber; and

removing the sacrificial substrate layer thereby defining a plurality of inkjet print heads.

2. The method of claim 1 , further comprising dividing the joined-together first and second wafers into a plurality of individual inkjet print heads prior to removing the sacrificial substrate layer.

3. The method of claim 1 , further comprising dividing the joined-together first and second wafers into a plurality of individual inkjet print heads after removing the sacrificial substrate layer.

4. The method of claim 1 , wherein forming the second wafer comprises forming a second dielectric layer on a second substrate layer with the second dielectric layer having a plurality of second openings therein defining, with adjacent portions of the second substrate layer, the plurality of inkjet chambers.

5. The method of claim 4 , wherein forming the second wafer further comprises:

forming a plurality of ink heaters, with each ink heater within a respective inkjet chamber; and

forming control circuitry on the second substrate layer and coupled to the plurality of ink heaters.

6. The method of claim 4 , wherein forming the second wafer further comprises forming a plurality of microfluidic passageways through the second substrate layer with each microfluidic passageway in communication with a respective inkjet chamber.

7. The method of claim 6 , wherein removing the sacrificial substrate layer and forming the plurality of microfluidic passageways is performed in a common etching operation.

8. The method of claim 1 , wherein removing the sacrificial substrate layer comprises removing the sacrificial substrate layer by at least one of wet etching and reactive ion etching.

9. The method of claim 1 , wherein the first dielectric layer comprises an oxide layer, and the sacrificial substrate layer comprises silicon.

10. A method of making a plurality of inkjet print heads from first and second wafers; the first wafer comprising a sacrificial substrate layer, and a first dielectric layer thereon having a plurality of first openings therein defining a plurality of inkjet orifices; and the second wafer having a plurality of inkjet chambers defined thereon; the first and second wafers being physically separated; the method comprising:

joining the first and second wafers together, by bringing together the physically separated first and second wafers, so that each inkjet orifice is aligned with a respective inkjet chamber; and

removing the sacrificial substrate layer thereby defining a plurality of inkjet print heads.

11. The method of claim 10 , further comprising dividing the joined-together first and second wafers into a plurality of individual inkjet print heads prior to removing the sacrificial substrate layer.

12. The method of claim 10 , further comprising dividing the joined-together first and second wafers into a plurality of individual inkjet print heads after removing the sacrificial substrate layer.

13. The method of claim 10 , wherein removing the sacrificial substrate layer comprises removing the sacrificial substrate layer by at least one of wet etching and reactive ion etching.

14. The method of claim 10 , wherein the first dielectric layer comprises an oxide layer, and the sacrificial substrate layer comprises silicon.

15. A method of making a plurality of inkjet print heads comprising:

forming a first wafer comprising a sacrificial substrate layer, and a first dielectric layer thereon having a plurality of first openings therein defining a plurality of inkjet orifices;

forming a second wafer having a plurality of inkjet chambers defined thereon, the second wafer being formed physically independent of the first wafer;

joining the first and second wafers together, by bringing together the physically independently formed first and second wafers, so that each inkjet orifice is aligned with a respective inkjet chamber;

removing the sacrificial substrate layer by wet etching; and

dividing the joined-together first and second wafers into the plurality of inkjet print heads.

16. The method of claim 15 , wherein forming the second wafer comprises forming a second dielectric layer on a second substrate layer with the second dielectric layer having a plurality of second openings therein defining, with adjacent portions of the second substrate layer, the plurality of inkjet chambers.

17. The method of claim 16 , wherein forming the second wafer further comprises:

forming a plurality of ink heaters, with each ink heater within a respective inkjet chamber; and

forming control circuitry on the second substrate layer and coupled to the plurality of ink heaters.

18. The method of claim 16 , wherein forming the second wafer further comprises forming a plurality of microfluidic passageways through the second substrate layer with each microfluidic passageway in communication with a respective inkjet chamber.

19. The method of claim 18 , wherein removing the sacrificial substrate layer and forming the plurality of microfluidic passageways is performed in a common etching operation.

20. The method of claim 15 , wherein the first dielectric layer comprises an oxide layer, and the sacrificial substrate layer comprises silicon.