# US 2009/0275151 A1 · Method Of Forming Printhead By Removing Sacrificial Material Through Nozzle Apertures

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- Number: US 2009/0275151 A1
- Document ID: US20090275151A1
- Status: Published application
- Kind: A1
- Application number: 12/501,473
- Filed: 2009-07-12
- Published: 2009-11-05
- Earliest claimed: 1997-07-15
- Assignees: Silverbrook Research Pty Ltd
- Inventors: Kia Silverbrook
- Web page: https://patentgrep.com/patent/US20090275151A1

## CPC

- B41J 2/14427: {Structure of ink jet print heads with thermal bend detached actuators}
- B41J 2/1626: {etching}
- B41J 2/1631: {photolithography}
- B41J 2/1639: {sacrificial molding}
- B41J 2/1642: {thin film formation by CVD [chemical vapor deposition]}
- B41J 2/1648: {Production of print heads with thermal bend detached actuators}
- Y10T 29/42: Piezoelectric device making
- Y10T 29/49401: Fluid pattern dispersing device making, e.g., ink jet
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method of fabricating an inkjet printhead by forming a plurality of actuators on a monolithic substrate, covering the actuators with a sacrificial material, covering the sacrificial material with a printhead surface layer, defining a plurality of nozzle apertures in the printhead surface layer such that each of the actuators corresponds to one of the nozzle apertures and then, removing at least some of the sacrificial material on each of the actuators through the nozzle aperture corresponding to each of the actuators.

## Claims

### Claim 1

A method of fabricating an inkjet printhead comprising the steps of:
forming a plurality of actuators on a monolithic substrate;
covering the actuators with a sacrificial material;
covering the sacrificial material with a printhead surface layer;
defining a plurality of nozzle apertures in the printhead surface layer such that each of the actuators corresponds to one of the nozzle apertures; and,
removing at least some of the sacrificial material on each of the actuators through the nozzle aperture corresponding to each of the actuators.

### Claim 2 (depends on 1)

A method according to claim 1 further comprising the step of supporting the actuators on the monolithic substrate by CMOS drive circuitry positioned between the monolithic substrate and the actuators and the monolithic substrate.

### Claim 3 (depends on 2)

A method according to claim 2 further comprising the step of depositing a protective layer over the CMOS drive circuitry and etching the protective layer to expose areas of the CMOS drive circuitry configured to be electrical contacts for the actuators.

### Claim 4 (depends on 3)

A method according to claim 3 wherein the protective layer is a nitride material.

### Claim 5 (depends on 3)

A method according to claim 3 wherein the protective layer is silicon nitride.

### Claim 6 (depends on 1)

A method according to claim 1 further comprising the step of forming etchant holes in the printhead surface layer for exposing the sacrificial material beneath the printhead surface layer to etchant, the etchant holes being smaller than the nozzle apertures such that during printer operation, ink is not ejected through the etchant holes.

### Claim 7 (depends on 6)

A method according to claim 6 wherein the printhead surface layer is a nitride material deposited over a sacrificial layer.

### Claim 8 (depends on 7)

A method according to claim 7 wherein the printhead surface layer is silicon nitride.

### Claim 9 (depends on 1)

A method according to claim 1 wherein the monolithic substrate has an ink ejection side providing a planar support surface for the CMOS drive circuitry and the plurality of actuators, the monolithic substrate also having an ink supply surface opposing the ink ejection side, the printhead surface layer has a roof layer extending in a plane parallel to the planar support surface, and side wall structures formed integrally with the roof layer and extending toward the planar support surface.

### Claim 10 (depends on 9)

A method according to claim 9 wherein the printhead surface layer has a plurality of filter structures formed integrally with the roof layer and positioned to filter ink flow to each of the actuators respectively.

### Claim 11 (depends on 10)

A method according to claim 10 further comprising the step of etching ink supply channels from the ink supply surface of the monolithic substrate to the planar support surface of the ink ejection side.

### Claim 12 (depends on 11)

A method according to claim 11 wherein the step of removing at least some of the sacrificial material on each of the actuators through the nozzle apertures is performed after the ink supply channels are etched from the ink supply surface.