Method of fabricating an ink jet printhead chip with differential expansion actuators

• US 7,022,250 B2
• Filed: 07/02/2004
• Issued: 04/04/2006
• Est. Priority Date: 07/15/1997
• Status: Expired due to Fees

• Current Assignee: Zamtec Limited (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Hassanzadeh, Parviz
• Assistant Examiner(s): CULBERT, ROBERTS P
• Application Number:
  US10/882,773
• Publication Number:
  US 20040252165A1
• Time in Patent Office: 641 Days
• Field of Search: 216/27, 298/901, 438/21, 347/20, 347/44, 347/47, 347/54, 347/56, 347/67, 347/75, 347/77
• US Class Current: 216/27
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/1601 Production of bubble jet print heads B41J2/1606, B41J2/162 take precedence
• 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 2/17503 Ink cartridges
• 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 2202/21 : Line printing
• CPC Class Codes: B41J 3/445 : Printers integrated in other types of apparatus, e.g. printers integrated in cameras
• 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: 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

Abstract

A method of fabricating an inkjet printhead chip includes the step of forming a layer of sacrificial material on a substrate, such that the layer is between three and ten microns thick. A first layer of thermal expansion material is formed on the sacrificial material. A heater circuit is formed on the first layer of thermal expansion material. The sacrificial material and the first layer of thermal expansion material are formed to permit the electrical circuit to make electrical contact with the drive circuitry. A second layer of the thermal expansion material is formed on the heater circuit. A suitable process is applied on the second layer of thermal expansion material to render a surface of the second layer hydrophilic. The sacrificial material is removed.

Claims

1. A method of fabricating a printhead chip for an inkjet printhead, the printhead chip including a wafer substrate that incorporates drive circuitry and defines a plurality of ink inlet channels, a plurality of nozzle arrangements positioned on the substrate, each nozzle arrangement including nozzle chamber walls that define a nozzle chamber and an ink ejection port in fluid communication with the nozzle chamber with an ink inlet channel opening into the nozzle chamber and an actuator that is positioned in the nozzle chamber, the actuator having an electrical circuit connected to the drive circuitry layer and positioned in thermal expansion material so that the expansion material experiences thermal expansion when the heating circuit receives an electrical signal from the drive circuitry layer and the actuator is displaced towards the ink ejection port to eject a drop of ink from the nozzle chamber, the method comprising the steps of:

forming a layer of sacrificial material on the substrate, such that the layer is between one and ten microns thick;

forming a first layer of the thermal expansion material on the sacrificial material;

forming the heater circuit on the first layer of thermal expansion material, the sacrificial material and the first layer of thermal expansion material being formed to permit the electrical circuit to make electrical contact with the drive circuitry;

forming a second layer of the thermal expansion material on the heater circuit wherein the expansion material is polytetrafluoroethylene (PTFE);

plasma processing the surface of the second layer of PTFE to render said surface hydrophilic; and

removing the sacrificial material.

2. A method as claimed in claim 1, in which the layer of sacrificial material is formed to be between three and six microns thick.

3. A method as claimed in claim 1, in which the thermal expansion material and the heater circuit are formed so that each actuator overlies a respective ink inlet opening.

4. A method as claimed in claim 1, which includes the steps of forming a further layer of sacrificial material on the second layer of PTFE, forming the nozzle chamber walls on the second layer of sacrificial material such that the nozzle chamber walls define the nozzle chamber and the ink ejection port in fluid communication with the nozzle chamber and removing the second layer of sacrificial material.

5. A method as claimed in claim 1 which includes the step of forming the first and second layers of expansion material and the heater circuit such that the actuator is a laminated structure with the heater circuit sandwiched between the first and second layers of expansion material.