Method of manufacture of an electrostatic ink jet printer

• US 6,235,212 B1
• Filed: 07/10/1998
• Issued: 05/22/2001
• 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): Gulakowski, Randy
• Assistant Examiner(s): Ahmed, Shamim
• Application Number:
  US09/112,825
• Time in Patent Office: 1,047 Days
• Field of Search: 216/27, 347/55, 347/62
• US Class Current: 216/27
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane
• 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 2/1639 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 2/16585 for paper-width or non-reciprocating print heads
• CPC Class Codes: B41J 2/17596 Ink pumps, ink valves
• CPC Class Codes: B41J 2002/041 Electromagnetic transducer
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• 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

This patent describes a method of manufacturing an electrostatic ink jet print head wherein an array of nozzles are formed on a substrate utilising planar monolithic deposition, lithographic and etching processes. Multiple ink jet heads are formed simultaneously on a single planar substrate such as a silicon wafer. The print heads can be formed utilising standard vlsi/ulsi processing and can include integrated drive electronics formed on the same substrate. The drive electronics preferably being of a CMOS type. In the final construction, ink can be ejected from the substrate substantially normal to the substrate plane.

Claims

1. A method of manufacture of a drop on demand ink jet print head arrangement including a series of nozzle chambers, said method comprising the steps of:

(a) utilising an initial semiconductor wafer having an electrical circuitry layer formed thereon;

(b) forming a bottom layer of conductive material on or in said electrical circuitry layer;

(c) depositing and etching a first hydrophobic layer on said bottom layer;

(d) depositing and etching a first sacrificial layer of sacrificial material on said first hydrophobic layer;

(e) depositing and etching a top layer of conductive material on said first sacrificial layer, said top layer including predetermined portions interconnecting with said electrical circuitry layer;

(f) depositing and etching a membrane layer on said top layer;

(g) depositing and etching a second sacrificial layer on said membrane layer, said second sacrificial layer forming a blank for said nozzle chamber walls;

(h) depositing and etching an inert material layer on said second sacrificial layer so as to form said nozzle chamber walls surrounding said nozzle chamber in addition to a nozzle fluid ejection hole in fluid communication with said nozzle chamber;

(i) etching an ink supply channel in fluid communication with said nozzle chamber; and

(j) etching away said sacrificial layers so as to leave a planar actuator which is defined by said top layer and said membrane layer, the actuator being arranged in the nozzle chamber above the bottom layer and being displaceable towards and away from said bottom layer, while remaining parallel to said bottom layer, to effect ink ejection, in use.

2. A method as claimed in claim 1 wherein said top layer and said membrane layer include a concertina edge so as to allow for movement of said membrane layer.

3. A method as claimed in claim 1 wherein said bottom layer is formed from a metal plane layer of said circuitry layer.

4. A method as claimed in claim 1 wherein said ink supply channel is formed by etching a channel from the back surface of said wafer.

5. A method as claimed in claim 1 wherein said step (h) includes etching a nozzle rim around said nozzle fluid ejection hole.

6. A method as claimed in claim 1 wherein said step (h) includes etching a series of small holes in at least one wall of said nozzle chamber.

7. A method as claimed in claim 1 wherein said hydrophobic layer comprises substantially polytetrafluoroethylene.

8. A method as claimed in claim 1 further including the step of depositing corrosion barriers over portions of said arrangement so as to reduce corrosion effects.

9. A method as claimed in claim 1 wherein said wafer comprises a double side polished CMOS wafer.

10. A method as claimed in claim 1 wherein said steps (i) and (j) are also utilised to simultaneously separate said wafer into separate printheads.