# US 8,465,659 B2 · Polymer layer removal on pzt arrays using a plasma etch

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- Number: US 8,465,659 B2
- Document ID: US8465659B2
- Status: Granted
- Kind: B2
- Application number: 13/011,409
- Filed: 2011-01-21
- Published: 2012-07-26
- Granted: 2013-06-18
- Earliest claimed: 2011-01-21
- Assignees: Xerox Corporation
- Applicants: Bryan R. Dolan; John R. Andrews; Bradley J. Gerner; Mark A. Cellura
- Inventors: Bryan R. Dolan; John R. Andrews; Bradley J. Gerner; Mark A. Cellura
- Web page: https://patentgrep.com/patent/US8465659B2

## CPC

- B41J 2/161: {of film type, deformed by bending and disposed on a diaphragm}
- B41J 2/1623: {bonding and adhesion}
- B41J 2/1631: {photolithography}
- B41J 2/1634: {laser machining}
- Y10T 428/31504: Composite [nonstructural laminate]
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method for forming an ink jet print head can include attaching a plurality of piezoelectric elements to a diaphragm, dispensing a dielectric fill layer over the diaphragm and the plurality of piezoelectric elements to encapsulate the piezoelectric elements, curing the dielectric fill layer to form an interstitial layer, then removing the interstitial layer from an upper surface of the plurality of piezoelectric elements using a plasma etch.

## Claims

### Claim 1

A method for forming an ink jet print head, comprising:
attaching a diaphragm attach material to a diaphragm, wherein the diaphragm comprises a plurality of openings;
attaching a plurality of piezoelectric elements to the diaphragm;
dispensing a dielectric fill material to encapsulate the plurality of piezoelectric elements and to contact the diaphragm, wherein the diaphragm attach material prevents the flow of dielectric fill material through the plurality of openings in the diaphragm;
curing the dielectric fill material to form an interstitial layer between the plurality of piezoelectric elements and over an upper surface of the plurality of piezoelectric elements; and
removing the interstitial layer from the upper surface of the plurality of piezoelectric elements using a plasma etch.

### Claim 2 (depends on 1)

The method of claim 1, wherein the plasma etch comprises:
introducing an oxygen gas into an etch chamber at a delivery rate sufficient to provide an equilibrium chamber pressure of between about 100 mTorr and about 200 mTorr; and
igniting a plasma at a radiofrequency power of between about 800 W and about 1,000 W.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
attaching the diaphragm attach material covers the plurality of openings through the diaphragm; and
subsequent to curing the dielectric fill material, removing the diaphragm attach material which covers the plurality of openings through the diaphragm.

### Claim 4 (depends on 3)

The method of claim 3, wherein the diaphragm attach material which covers the plurality of openings through the diaphragm is removed by laser ablation.

### Claim 5 (depends on 4)

The method of claim 4, further comprising removing a portion of the interstitial layer between piezoelectric elements during the removal of the diaphragm attach material which covers the plurality of openings through the diaphragm.

### Claim 6 (depends on 1)

The method of claim 1, wherein the dispensing of the dielectric fill material dispenses a material comprising a thermoset polymer.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
the diaphragm is part of a jet stack subassembly comprising an inlet/outlet plate and a body plate;
the diaphragm attach material attaches the diaphragm to the body plate;
attaching the diaphragm attach material to the diaphragm covers the plurality of opening through the diaphragm;
subsequent to curing the dielectric fill material, removing the diaphragm attach material which covers the plurality of openings through the diaphragm; and
subsequent to removing the diaphragm attach material which covers the plurality of openings through the diaphragm, attaching an aperture plate comprising a plurality of nozzles to the body plate.

### Claim 8 (depends on 7)

The method of claim 7, further comprising:
electrically coupling the plurality of piezoelectric elements to a plurality of printed circuit board electrodes.

### Claim 9 (depends on 1)

The method of claim 1, further comprising:
attaching a piezoelectric element layer to a transfer carrier;
dicing the piezoelectric element layer to form the plurality of piezoelectric elements; and
subsequent to attaching the plurality of piezoelectric elements to the diaphragm, removing the transfer carrier from the plurality of piezoelectric elements.

### Claim 10 (depends on 9)

The method of claim 9, wherein the attachment of the piezoelectric element layer to the transfer carrier attaches a piezoelectric element layer comprising a nickel-plated lead-zirconate-titanate piezoelectric layer.

### Claim 11

A method for forming an ink jet print head, comprising:
attaching a diaphragm attach material to a diaphragm, wherein the diaphragm comprises a plurality of openings therethrough;
attaching a plurality of piezoelectric elements to the diaphragm;
dispensing a dielectric fill material to encapsulate the plurality of piezoelectric elements and to contact the diaphragm, wherein the diaphragm attach material prevents the flow of dielectric fill material through the plurality of openings in the diaphragm;
curing the dielectric fill material to form an interstitial layer between the plurality of piezoelectric elements and over an upper surface of the plurality of piezoelectric elements;
placing a patterned adhesive layer and a patterned removable liner over the interstitial layer, wherein openings within the patterned adhesive layer and the patterned removable liner expose the interstitial layer at locations which overlie the piezoelectric elements; and
removing the interstitial layer from the upper surface of the plurality of piezoelectric elements with a plasma etch using the patterned removable liner and the patterned adhesive layer as an etch mask.

### Claim 12 (depends on 11)

The method of claim 11, wherein the plasma etch comprises:
introducing an oxygen gas into an etch chamber at a delivery rate sufficient to provide an equilibrium chamber pressure of between about 100 mTorr and about 200 mTorr; and
igniting a plasma at a radiofrequency power of between about 800 W and about 1,000 W.

### Claim 13 (depends on 11)

The method of claim 11, further comprising:
placing a conductor into the openings within the patterned adhesive layer and the patterned removable liner;
subsequent to placing the conductor into the openings, removing the removable liner; and
electrically coupling the plurality of piezoelectric elements with a plurality of printed circuit board (PCB) electrodes using the conductor.

### Claim 14 (depends on 13)

The method of claim 13, further comprising:
mechanically attaching the interstitial layer to a PCB using the patterned adhesive layer.

### Claim 15 (depends on 11)

The method of claim 11, further comprising:
clearing the diaphragm attach material, the interstitial layer, and the patterned adhesive layer from the openings in the diaphragm using laser ablation.

### Claim 16 (depends on 11)

The method of claim 11, further comprising:
attaching a piezoelectric element layer to a transfer carrier;
dicing the piezoelectric element layer to form the plurality of piezoelectric elements; and
subsequent to attaching the plurality of piezoelectric elements to the diaphragm, removing the transfer carrier from the plurality of piezoelectric elements.

### Claim 17

A method for forming an ink jet print head, comprising:
attaching a piezoelectric element layer to a transfer carrier;
dicing the piezoelectric element layer to form a plurality of piezoelectric elements;
attaching the plurality of piezoelectric elements to a diaphragm of a jet stack subassembly, wherein the jet stack subassembly further comprises an inlet/outlet plate, a body plate, a plurality of openings in the diaphragm, and a diaphragm attach material which covers the plurality of openings in the diaphragm;
dispensing a dielectric fill material to encapsulate the plurality of piezoelectric elements and to contact the diaphragm, wherein the diaphragm attach material prevents the flow of dielectric fill material through the plurality of openings in the diaphragm;
curing the dielectric fill material to form an interstitial layer between the plurality of piezoelectric elements and over an upper surface of the plurality of piezoelectric elements;
placing a patterned adhesive layer and a patterned removable liner over the interstitial layer, wherein openings within the patterned adhesive layer and the patterned removable liner expose the interstitial layer at locations which overlie the piezoelectric elements;
removing the interstitial layer from the upper surface of the plurality of piezoelectric elements with a plasma etch using the patterned removable liner and the patterned adhesive layer as an etch mask, wherein the plasma etch comprises introducing an oxygen gas into an etch chamber at a delivery rate sufficient to provide an equilibrium chamber pressure of between about 100 mTorr and about 200 mTorr and igniting a plasma at a radiofrequency power of between about 800 W and about 1,000 W;
placing a conductive paste within the openings in the patterned removable liner and the patterned adhesive layer;
removing the patterned removable liner;
using a laser beam, ablating the diaphragm attach material, the interstitial layer, and the patterned adhesive layer from the plurality of openings in the diaphragm, wherein the body plate and the inlet/outlet plate mask the laser beam;
mechanically attaching a printed circuit board (PCB) to the interstitial layer with the patterned adhesive layer, wherein the conductive paste electrically coupled PCB electrodes to the piezoelectric elements; and
attaching a manifold to the PCB.

### Claim 18

A method for forming an assembly, comprising:
encapsulating a piezoelectric structure within an epoxy; and
plasma etching at least a portion of the epoxy to expose the piezoelectric structure.

### Claim 19 (depends on 18)

The method of claim 18, wherein the plasma etch comprises:
introducing an oxygen gas into an etch chamber at a delivery rate sufficient to provide an equilibrium chamber pressure of between about 100 mTorr and about 200 mTorr; and
igniting a plasma at a radiofrequency power of between about 800 W and about 1,000 W.