Method of fabricating monolithic microelectromechanical fluid ejection device

• US 7,398,597 B2
• Filed: 01/03/2005
• Issued: 07/15/2008
• Est. Priority Date: 07/15/1997
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Cazan; Livius R.
• Application Number:
  US11/026,046
• Publication Number:
  US 20050120552A1
• Time in Patent Office: 1,289 Days
• Field of Search: 298/901, 296/11, 298/31, 216/27, 438/21, 347/56, 347/61
• US Class Current: 29/890.1
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane
• 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 2/1626 etching
• 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 2/1643 thin film formation by plating
• CPC Class Codes: B41J 2/1645 thin film formation by spincoating
• CPC Class Codes: B41J 2/1646 thin film formation by sputtering
• CPC Class Codes: B41J 2/1648 Production of print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/16585 for paper-width or non-reciprocating print heads
• CPC Class Codes: B41J 2/17513 Inner structure
• 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 2002/14443 : Nozzle guard
• CPC Class Codes: B41J 2202/21 : Line printing
• CPC Class Codes: G06F 21/79 : in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 21/86 : Secure or tamper-resistant housings
• CPC Class Codes: G06F 2221/2129 : Authenticate client device independently of the user
• CPC Class Codes: G06K 1/121 : by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26
• CPC Class Codes: G06K 19/06037 : multi-dimensional coding
• CPC Class Codes: G06K 7/14 : using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1417 : 2D bar codes
• CPC Class Codes: G07F 7/08 : by coded identity card or credit card or other personal identification means without personal verification means G07F7/02
• CPC Class Codes: G07F 7/086 : by passive credit-cards adapted therefor, e.g. constructive particularities to avoid counterfeiting, e.g. by inclusion of a physical or chemical security-layer for security documents G07D7/00; for the reading of record-carriers in general G06K7/00; for the design of coded credit-cards G06K19/10
• CPC Class Codes: G07F 7/12 : Card verification
• CPC Class Codes: G11C 11/56 : using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
• CPC Class Codes: H04N 23/00 : Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 5/2628 : Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation
• CPC Class Codes: Y10T 29/49083 : Heater type
• CPC Class Codes: Y10T 29/49117 : Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49128 : Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49169 : Assembling electrical component directly to terminal or elongated conductor
• CPC Class Codes: Y10T 29/49172 : by molding of insulating material
• CPC Class Codes: Y10T 29/49401 : Fluid pattern dispersing device making, e.g., ink jet

Abstract

A method for forming a printhead having a very high dot-per-inch printing capability is described. The method includes forming a layer containing electronic control circuits upon a semiconductor wafer. Nozzle chambers are then etched into the wafer and corresponding fluid ejection assemblies are formed for each nozzle chamber. Ink inlets for the nozzle chambers are produced by back-etching through the wafer. Steps for fabricating thermal bend actuators to eject ink from the nozzles are also described.

Claims

1. A method for fabricating a monolithic microelectromechanical fluid ejection device comprising a plurality of fluid ejection nozzles upon a semiconductor wafer, the method including:

forming a layer containing electronic control circuits upon the wafer;

etching nozzle chambers into the wafer to contain fluid;

forming fluid ejection assemblies for each nozzle chamber including depositing a first layer of heater material, depositing a layer of glass over the first layer of heater material, and depositing a second layer of heater material over the layer of glass; and

back-etching through the wafer to define ink inlets in communication with the nozzle chambers.

2. A method according to claim 1, wherein the step of forming fluid ejection assemblies includes depositing heater material on the wafer to heat an activating arm of the fluid ejection assemblies in their complete state.

3. A method according to claim 1, wherein the step of depositing the first layer of heater material comprises depositing a cupronickel layer.

4. A method according to claim 3, wherein the step of depositing the cupronickel layer includes:

depositing a layer of anti-corrosion material;

depositing a seed layer; and

electroplating the cupronickel layer.

5. A method according to claim 1, including etching the first and second layers of heater material and the layer of glass with a mask defining actuators and paddles of the fluid ejection assemblies.

6. A method according to claim 5, including forming nozzle chamber walls by depositing sacrificial material onto the wafer and etching the sacrificial material with a mask defining the nozzle chamber walls.

7. A method according to claim 1, including hydrophobizing a fluid ejection surface of the fluid ejection device.

8. A method according to claim 1, wherein the layer containing electronic control circuits comprises a CMOS layer.