Method of fabricating an ink jet printhead chip having actuator mechanisms located about ejection ports

• US 7,179,395 B2
• Filed: 12/08/2003
• Issued: 02/20/2007
• Est. Priority Date: 06/09/1998
• Status: Expired due to Fees

• Current Assignee: Zamtec Limited (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia, McAvoy, Gregory John
• Primary Examiner(s): Ahmed; Shamim
• Application Number:
  US10/728,924
• Publication Number:
  US 20040118807A1
• Time in Patent Office: 1,170 Days
• Field of Search: 216/27, 216/41, 438/21, 347/54, 347/59
• US Class Current: 216/27
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• CPC Class Codes: B41J 2/1433 Structure of nozzle plates
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/16 Production of nozzles
• CPC Class Codes: B41J 2/1623 bonding and adhesion
• CPC Class Codes: B41J 2/1628 dry etching
• CPC Class Codes: B41J 2/1629 wet etching
• CPC Class Codes: B41J 2/1631 photolithography
• CPC Class Codes: B41J 2/1632 machining
• CPC Class Codes: B41J 2/1635 dividing the wafer into individual chips
• CPC Class Codes: B41J 2/1637 molding
• CPC Class Codes: B41J 2/1639 sacrificial molding
• CPC Class Codes: B41J 2/1642 thin film formation by CVD [chemical vapor deposition]
• CPC Class Codes: B41J 2/1648 Production of print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/17596 Ink pumps, ink valves
• CPC Class Codes: B41J 2002/041 Electromagnetic transducer
• CPC Class Codes: B41J 2002/14346 Ejection by pressure produced by thermal deformation of ink chamber, e.g. buckling
• CPC Class Codes: B41J 2002/14435 Moving nozzle made of thermal bend detached actuator
• CPC Class Codes: B41J 2002/14475 characterised by nozzle shapes or number of orifices per chamber
• CPC Class Codes: B41J 2202/15 Moving nozzle or nozzle plate
• CPC Class Codes: Y10T 29/49128 : Assembling formed circuit to base
• CPC Class Codes: Y10T 29/4913 : Assembling to base an electrical component, e.g., capacitor, etc.
• CPC Class Codes: Y10T 29/49155 : Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/49156 : with selective destruction of conductive paths
• CPC Class Codes: Y10T 29/49401 : Fluid pattern dispersing device making, e.g., ink jet

Abstract

A method of fabricating an inkjet printhead chip includes the step of etching a drive circuitry layer that is positioned on a substrate to define regions for roof structures. A first layer of a thermally expandable material is deposited on the drive circuitry layer to cover said regions. The first layer of thermally expandable material and the drive circuitry layer are etched to define a deposition zone for heating circuit material at each region and contact vias for the heating circuit material. At least one heating circuit is formed at each region in electrical contact with the drive circuitry layer by means of the contact vias. A second layer of a thermally expandable material is deposited on the heating circuit material. Both layers of thermally expandable material are etched to define a roof structure at each region such that each roof structure includes at least one actuator at each region and defines an ink ejection port, and such that each heating circuit is embedded in each respective actuator in a position such that heating of the expandable material by the heating circuit results in differential thermal expansion of the actuator and resultant displacement of each actuator. The substrate is etched to define a plurality of nozzle chambers and corresponding ink inlet channels, such that each nozzle chamber and its associated ink inlet channel are positioned beneath each roof structure.

Claims

1. A method of fabricating an inkjet printhead chip, the method comprising the steps of:

etching a drive circuitry layer that is positioned on a substrate to define regions for roof structures;

depositing a first layer of a thermally expandable material on the drive circuitry layer to cover said regions;

etching the first layer of thermally expandable material and the drive circuitry layer to define a deposition zone for heating circuit material at each region and contact vias for the heating circuit material;

forming at least one heating circuit at each region in electrical contact with the drive circuitry layer by means of the contact vias;

depositing a second layer of a thermally expandable material on the heating circuit material;

etching both layers of thermally expandable material to define a roof structure at each region such that each roof structure includes at least one actuator at each region and defines an ink ejection port, and such that each heating circuit is embedded in each respective actuator in a position such that heating of the expandable material by the heating circuit results in differential thermal expansion of the actuator and resultant displacement of each actuator; and

etching the substrate to define a plurality of nozzle chambers and corresponding ink inlet channels, such that each nozzle chamber and its associated ink inlet channel are positioned beneath each roof structure.

2. A method as claimed in claim 1, in which the steps of depositing the first and second layers of thermally expandable material comprise the steps of depositing first and second layers of polytetrafluoroethylene.

3. A method as claimed in claim 1, which includes the step of forming a plurality of heating circuits at each region and etching the layers of thermally expandable material so that each roof structure includes a plurality of actuators positioned about the ink ejection port, the layers being etched so that an arm is interposed between consecutive actuators and a rim that defines the ink ejection port is mounted on the arms.

4. A method as claimed in claim 1, which includes the step of crystallographically etching the substrate through the etched layers of the thermally expandable material to define the nozzle chambers.

5. A method as claimed in claim 1, in which the substrate is back-etched to define the ink inlet channels.

6. A method as claimed in claim 1, which includes the step of depositing and patterning a conductive material on the first layer of thermally expandable material using a lift-off process.

7. A method as claimed in claim 6, which includes the step of depositing and patterning one of the conductive materials selected from the group containing gold and copper.