Method of fabricating a micro-electromechanical device having a laminated actuator

• US 6,905,620 B2
• Filed: 12/08/2003
• Issued: 06/14/2005
• Est. Priority Date: 10/16/1998
• Status: Expired due to Fees

• Current Assignee: Zamtec Limited (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Mills, Gregory
• Assistant Examiner(s): CULBERT, ROBERTS P
• Application Number:
  US10/729,081
• Publication Number:
  US 20040118808A1
• Time in Patent Office: 554 Days
• Field of Search: 216/27, 438/21, 298/901, 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 2/04505 aiming at correcting alignment
• CPC Class Codes: B41J 2/04516 preventing formation of satellite drops
• CPC Class Codes: B41J 2/04518 reducing costs
• CPC Class Codes: B41J 2/0452 reducing demand in current or voltage
• CPC Class Codes: B41J 2/04528 aiming at warming up the head
• CPC Class Codes: B41J 2/04541 Specific driving circuit
• CPC Class Codes: B41J 2/04543 Block driving
• CPC Class Codes: B41J 2/04553 detecting ambient temperature
• CPC Class Codes: B41J 2/04563 detecting head temperature; Ink temperature
• CPC Class Codes: B41J 2/04565 detecting heater resistance
• CPC Class Codes: B41J 2/0457 Power supply level being detected or varied
• CPC Class Codes: B41J 2/04571 detecting viscosity
• CPC Class Codes: B41J 2/04585 controlling heads based on thermal bent actuators
• CPC Class Codes: B41J 2/04588 using a specific waveform
• CPC Class Codes: B41J 2/0459 Height of the driving signal being adjusted
• CPC Class Codes: B41J 2/04591 Width of the driving signal being adjusted
• CPC Class Codes: B41J 2/04593 Dot-size modulation by changing the size of the drop
• CPC Class Codes: B41J 2/04596 Non-ejecting pulses
• CPC Class Codes: B41J 2/04598 Pre-pulse
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/155 : for line printing
• 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 2/1628 : 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 2/1646 : thin film formation by sputtering
• CPC Class Codes: B41J 2/1648 : Production of print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2002/14419 : Manifold
• CPC Class Codes: B41J 2002/14491 : Electrical connection
• CPC Class Codes: B41J 25/005 : for serial printing movements superimposed to character- or line-spacing movements

Abstract

A method of fabricating a micro-electromechanical device includes the step of carrying out an integrated circuit fabrication process on a wafer to form control circuitry. Sacrificial material is deposited on the wafer. The sacrificial material is etched to form a deposition zone for a heater layer of a conductive material and contact regions for the heater layer to make electrical contact with the electrical power supply. The heater layer is deposited on the etched sacrificial material. The heater layer is etched so that the heater layer defines a heating circuit. A layer of a dielectric material is deposited on the heater layer. A bend compensator layer of the same material as the heater layer is deposited on the dielectric layer with substantially the same deposition characteristics as applied to the heater layer. The dielectric and bend compensator layers are etched to define the actuator arm. The sacrificial material is etched away.

Claims

1. A method of fabricating a micro-electromechanical device that includes a wafer, an elongate actuator arm that is anchored to the substrate at a fixed end and is connected to an electrical power supply, the elongate actuator arm having a free end that is displaceable to perform work when an electrical current is applied to the actuator arm and control circuitry that is positioned on the substrate to be interposed between the substrate and the actuator arm and for enabling and disabling the electrical power supply on receipt of a control signal, the method comprising the steps of:

carrying out an integrated circuit fabrication process on the wafer to form the control circuitry;

depositing sacrificial material on the wafer;

etching the sacrificial material to form a deposition zone for a heater layer of a conductive material and contact regions for the heater layer to make electrical contact with the electrical power supply;

depositing the heater layer on the etched sacrificial material;

etching the heater layer so that the heater layer defines a heating circuit;

depositing a layer of a dielectric material on the heater layer;

depositing a bend compensator layer of the same material as the heater layer on the dielectric layer with substantially the same deposition characteristics as applied to the heater layer;

etching the dielectric and bend compensator layers to define the actuator arm; and

etching away the sacrificial material.

2. A method as claimed in claim 1, in which the step of carrying out the integrated circuit fabrication process comprises the step of carrying out a CMOS process.

3. A method as claimed in claim 1, in which the step of depositing sacrificial material on the wafer includes the step of depositing at least one metal layer on the wafer.

4. A method as claimed in claim 1, in which the step of etching the heater layer includes the step of etching a discontinuity in the heater layer so that one part of the heater layer defines the heating circuit, while a remaining part of the heater layer defines structural support for the actuator arm.

5. A method as claimed in claim 1, in which the steps of depositing the heater layer and the bend compensator layer both comprise the step of depositing a layer of Titanium Nitride.

6. A method as claimed in claim 1, in which the step of depositing the dielectric layer includes the step of depositing a layer of PECVD glass.

7. A method as claimed in claim 1, in which the steps of depositing the heater layer, the bend compensator layer and the dielectric layer are carried out so that the dielectric layer is subjected to compressive residual stress.