# US 2010/0167433 A1 · Piezoelectric inkjet printhead and method of manufacturing the same

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- Number: US 2010/0167433 A1
- Document ID: US20100167433A1
- Status: Published application
- Kind: A1
- Application number: 12/722,843
- Filed: 2010-03-12
- Published: 2010-07-01
- Earliest claimed: 2006-01-26
- Assignees: Samsung Electronics Co., Ltd.
- Inventors: Jae-chang Lee; Jae-woo Chung; Kyo-yool Lee; Chang-seung Lee; Sung-gyu Kang
- Web page: https://patentgrep.com/patent/US20100167433A1

## CPC

- B41J 2/14233: {of film type, deformed by bending and disposed on a diaphragm}
- B41J 2/161: {of film type, deformed by bending and disposed on a diaphragm}
- B41J 2/1623: {bonding and adhesion}
- B41J 2/1628: {dry etching}
- B41J 2/1629: {wet etching}
- Y10T 29/42: Piezoelectric device making
- Y10T 29/49401: Fluid pattern dispersing device making, e.g., ink jet
- 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 piezoelectric inkjet printhead including an upper substrate formed of a single crystal silicon substrate or an SOI substrate and having an ink inlet therethrough, and a lower substrate formed of an SOI substrate having a sequentially stacked structure with a first silicon layer, an intervening oxide layer, and a second silicon layer in which a manifold, pressure chambers, and dampers are formed in the second silicon layer by wet or dry etching, and nozzles are formed through the intervening oxide layer and the first silicon layer by dry etching, and a method of manufacturing the same.

## Claims

### Claim 1

A method of manufacturing a piezoelectric inkjet printhead, comprising:
processing a lower silicon-on-insulator substrate having a sequentially stacked structure with a first silicon layer, an intervening oxide layer, and a second silicon layer by etching the second silicon layer to form a manifold, a plurality of pressure chambers arranged along at least one side of the manifold and connected with the manifold, and a plurality of dampers connected with the pressure chambers, and by etching the first silicon layer and the intervening oxide layer to form a plurality of vertical nozzles through the first silicon layer and the intervening oxide layer to corresponding ones of the plurality of dampers;
stacking and bonding an upper substrate on the lower substrate;
reducing the upper substrate to a predetermined thickness; and
forming a piezoelectric actuator on the upper substrate to apply a driving force to the respective pressure chambers to eject ink.

### Claim 2 (depends on 1)

The method of claim 1, wherein the dampers are formed to have a depth substantially equal to a thickness of the second silicon layer by etching the second silicon layer using the intervening oxide layer as an etch stop layer, and the nozzles are formed to have a length substantially equal to a total thickness of the first silicon layer and the intervening oxide layer or substantially equal to a thickness of the first silicon layer.

### Claim 3 (depends on 2)

The method of claim 2, wherein the manifold has a depth smaller than the thickness of the second silicon layer, and the pressure chambers have a depth smaller than the depth of the manifold.

### Claim 4 (depends on 1)

The method of claim 1, wherein the processing of the lower substrate comprises:
forming a first etch mask on a top surface of the second silicon layer, the first etch mask including a first opening corresponding to the manifold, second openings corresponding to the pressure chambers, and third openings corresponding to the dampers;
forming a second etch mask on the top surface of the second silicon layer and a top surface of the first etch mask, the second etch mask covering the second openings and opening the first and third openings;
forming a third etch mask on the top surface of the second silicon layer and a top surface of the second etch mask, the third etch mask covering the first and second openings and opening the third openings; and
forming the manifold, the pressure chambers, and the dampers by etching the second silicon layer of the lower substrate sequentially using the third etch mask, the second etch mask, and the first etch mask.

### Claim 5 (depends on 4)

The method of claim 4, wherein the manifold, the pressure chambers, and the dampers comprise sidewalls inclined with respect to an ink ejecting direction by wet etching the second silicon layer of the lower substrate.

### Claim 6 (depends on 5)

The method of claim 5, wherein first and second ends of each of the plurality of pressure chambers taper toward the manifold and corresponding ones of the plurality of dampers, respectively, and are connected to the manifold and the corresponding ones of the plurality of dampers, respectively.

### Claim 7 (depends on 5)

The method of claim 5, wherein the first opening, the second openings, and the third openings are spaced from each other by a predetermined distance.

### Claim 8 (depends on 5)

The method of claim 5, wherein the first and second etch masks are formed of silicon oxide layers, and the third etch mask is formed of at least one layer selected from the group consisting of a silicon oxide layer, a parylene layer, and a Si3N4 layer.

### Claim 9 (depends on 5)

The method of claim 5, wherein the wet etching of the second silicon layer of the lower substrate is performed using tetramethyl ammonium hydroxide or KOH as a silicon etchant.

### Claim 10 (depends on 4)

The method of claim 4, wherein the manifold, the pressure chambers, and the dampers comprise sidewalls vertically formed with respect to an ink ejecting direction by dry etching the second silicon layer of the lower substrate.

### Claim 11 (depends on 10)

The method of claim 10, wherein first and second ends of the second openings are connected to the first opening and the third openings, respectively.

### Claim 12 (depends on 10)

The method of claim 10, wherein the first and second etch masks are formed of silicon oxide layers, and the third etch mask is formed of at least one layer selected from the group consisting of a silicon oxide layer, a photoresist layer, and a Si3N4 layer.

### Claim 13 (depends on 10)

The method of claim 10, wherein the dry etching of the second silicon layer of the lower substrate comprises:
performing reactive ion etching using inductively coupled plasma.

### Claim 14 (depends on 1)

The method of claim 1, wherein the nozzles are formed into a vertical hole shape having a constant diameter by dry etching the first silicon layer and the intervening oxide layer of the lower substrate.

### Claim 15 (depends on 14)

The method of claim 14, wherein the dry etching of the first silicon layer and the intervening oxide layer of the lower substrate comprises:
performing reactive ion etching using inductively coupled plasma.

### Claim 16 (depends on 1)

The method of claim 1, wherein the upper substrate is formed of a single crystal silicon substrate or an SOI substrate.

### Claim 17 (depends on 1)

The method of claim 1, further comprising:
forming an ink inlet in the upper substrate, the ink inlet being connected with the manifold.

### Claim 18 (depends on 17)

The method of claim 17, wherein the forming of the ink inlet is performed prior to the stacking and bonding of the upper substrate or after the reducing of the upper substrate.

### Claim 19 (depends on 17)

The method of claim 17, wherein the forming of the ink inlet comprises:
performing dry or wet etching.

### Claim 20 (depends on 1)

The method of claim 1, wherein the bonding of the upper substrate on the lower substrate comprises:
performing silicon direct bonding to bond the upper substrate and the lower substrate.

### Claim 21 (depends on 1)

The method of claim 1, wherein the reducing of the upper substrate is performed by dry or wet etching.

### Claim 22 (depends on 1)

The method of claim 1, wherein the reducing of the upper substrate comprises:
performing chemical-mechanical polishing.

### Claim 23 (depends on 1)

The method of claim 1, wherein the forming of the piezoelectric actuator comprises:
forming a lower electrode on the upper substrate;
forming a plurality of piezoelectric layers on the lower electrode, the piezoelectric layers corresponding to the pressure chambers;
forming an upper electrode on each of the piezoelectric layers; and
performing polling on the respective piezoelectric layers by applying an electric field to the piezoelectric layers to activate a piezoelectric characteristic of the piezoelectric layers.

### Claim 24

A method of manufacturing a printhead including an upper silicon substrate having an ink inlet and a piezoelectric actuator and a lower silicon substrate having first and second silicon layers separated by an intervening oxide layer, the method comprising:
forming a manifold, a plurality of pressure chambers, and a plurality of dampers in the second silicon layer of the lower silicon substrate;
forming a plurality of nozzles in the intervening oxide layer and the first silicon layer of the lower silicon substrate; and
attaching the upper and lower silicon substrates together to form an ink flow path defined by the ink inlet, the manifold, the plurality of pressure chambers, the plurality of dampers, and the plurality of nozzles.

### Claim 25 (depends on 24)

The method of claim 24, wherein the forming of the manifold, the plurality of pressure chambers, and the plurality of dampers comprises:
wet etching the second silicon layer of the lower substrate to form the manifold, the plurality of pressure chambers, and the plurality of dampers in the second silicon layer.

### Claim 26 (depends on 25)

The method of claim 25, wherein the wet etching of the second silicon layer comprises:
wet etching first portions of the second silicon layer to a first predetermined depth corresponding to a thickness of the second silicon layer to form the plurality of dampers;
wet etching second portions of the second silicon layer to a second predetermined depth to form the plurality of pressure chambers; and
wet etching a third portion of the second silicon layer to a third predetermined depth to form the manifold.

### Claim 27 (depends on 24)

The method of claim 24, wherein the forming of the manifold, the plurality of pressure chambers, and the plurality of dampers comprises:
dry etching the second silicon layer of the lower substrate to form the manifold, the plurality of pressure chambers, and the plurality of dampers in the second silicon layer.

### Claim 28 (depends on 27)

The method of claim 27, wherein the dry etching of the second silicon layer comprises:
dry etching first portions of the second silicon layer to a first predetermined depth corresponding to a thickness of the second silicon layer to form the plurality of dampers;
dry etching second portions of the second silicon layer to a second predetermined depth to form the plurality of pressure chambers; and
dry etching a third portion of the second silicon layer to a third predetermined depth to form the manifold.

### Claim 29 (depends on 24)

The method of claim 24, wherein the forming of the plurality of nozzles comprises:
dry etching the intervening layer and the first silicon layer of the lower substrate to form the plurality of nozzles in the intervening layer and the first silicon layer.

### Claim 30 (depends on 29)

The method of claim 29, wherein the dry etching of the intervening layer and the first silicon layer comprises:
dry etching a portion of the intervening layer and the first silicon layer to a predetermined depth corresponding to thicknesses of the intervening oxide layer and the first silicon layer.

### Claim 31

A method of manufacturing a piezoelectric inkjet printhead, the method comprising:
forming an ink inlet on an upper substrate allow an inflow of ink;
forming a manifold to connect with the ink inlet, a plurality of pressure chambers arranged along at least one side of the manifold and connected with the manifold, a plurality of dampers connected with the pressure chambers, and a plurality of nozzles connected with the dampers on a lower substrate formed of a silicon-on-insulator substrate; and
forming a piezoelectric actuator on the upper substrate to apply a driving force to the plurality of pressure chambers to eject the ink,
wherein the upper substrate is stacked and bonded on the lower substrate.