# US 10,479,085 B2 · Printhead electrical interconnects

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- Number: US 10,479,085 B2
- Document ID: US10479085B2
- Status: Granted
- Kind: B2
- Application number: 15/749,399
- Filed: 2015-10-21
- Published: 2018-08-09
- Granted: 2019-11-19
- Earliest claimed: 2015-10-21
- Assignees: Hewlett-Packard Development Company, L.P.
- Applicants: Hewlett-Packard Development Company, L.P.
- Inventors: Devin Alexander Mourey; Chien-Hua Chen; Michael W. Cumbie
- Web page: https://patentgrep.com/patent/US10479085B2

## CPC

- B41J 2/1637: {molding}
- B41J 2/1603: {of the front shooter type}
- B41J 2/1626: {etching}
- B41J 2/164: {thin film formation}
- B41J 2/175: Ink supply systems {; Circuit parts therefor}
- B41J 2/17503: {Ink cartridges}
- B41J 2202/22: Manufacturing print heads
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS

## Abstract

In one example, a method for fabricating a printhead is described. The method may include applying an electrical interconnect between a printhead die and an electrical fan out structure embedded in a molding of a printhead via a direct patterning additive process. The method may further include applying a passivation layer over the electrical interconnect as a dry film laminate.

## Claims

### Claim 1

A method comprising:
applying an electrical interconnect between a printhead die and an electrical fan out structure embedded in a molding of a printhead via a direct patterning additive process; and
applying a passivation layer over the electrical interconnect as a dry film laminate.

### Claim 2 (depends on 1)

The method of claim 1, wherein the direct patterning additive process comprises:
placing a shadow mask over the printhead; and
applying a conductive material via one of an evaporation, a sputtering, or a screen printing to form the electrical interconnect in a region of the printhead defined by the shadow mask.

### Claim 3 (depends on 2)

The method of claim 2, wherein the shadow mask is to cover a portion of the printhead die containing a printhead nozzle and at least a portion of the electrical fan out structure.

### Claim 4 (depends on 1)

The method of claim 1, wherein the direct patterning additive process comprises:
a jet dispensing of a conductive material to form the electrical interconnect.

### Claim 5 (depends on 1)

The method of claim 1, wherein the applying the electrical interconnect comprises depositing a conductive material over a surface of the printhead, the surface comprising: a contact pad of the printhead die, a portion of the molding, and a contact pad of the electrical fan out structure.

### Claim 6 (depends on 1)

The method of claim 1, wherein the electrical fan out structure comprises one of:
a printed circuit assembly;
a flex circuit; or
a lead frame.

### Claim 7 (depends on 1)

The method of claim 1, wherein the molding comprises an epoxy mold compound.

### Claim 8 (depends on 1)

The method of claim 1, wherein the passivation layer comprises a negative photo-resist.

### Claim 9 (depends on 8)

The method of claim 8, wherein the negative photo-resist comprises:
an epoxy resin;
a gamma butyrolactone; and
a triaryl sulfonium salt.

### Claim 10 (depends on 1)

The method of claim 1, further comprising:
attaching the printhead die to a support medium;
attaching the electrical fan out structure to the support medium;
embedding the printhead die and the electrical fan out structure in the molding to create the printhead; and
removing the support medium from the printhead.

### Claim 11 (depends on 1)

The method of claim 1, further comprising:
forming a printing fluid channel in a side of the molding opposite to a side of the molding containing the printhead die and the electrical fan out structure.

### Claim 12

A device comprising:
a printhead die;
a printed circuit assembly;
a molding, wherein the printhead die and the printed circuit assembly are embedded in a surface of the molding; and
an interconnect structure comprising:
an electrical interconnect over an electrical contact of the printhead die, an electrical contact of the printed circuit assembly, and a portion of the surface of the molding between the printhead die and the printed circuit assembly; and
a passivation layer over the electrical interconnect, wherein a thickness of the interconnect structure is less than 100 microns.

### Claim 13 (depends on 12)

The device of claim 12, wherein materials for forming the electrical interconnect structure are not deposited in a nozzle region of the printhead die.

### Claim 14 (depends on 12)

The device of claim 12, wherein the printed circuit assembly is embedded in the surface of the molding via a direct patterning additive process.

### Claim 15 (depends on 12)

The device of claim 12, wherein the molding comprises an epoxy mold compound.

### Claim 16 (depends on 12)

The device of claim 12, wherein the passivation layer comprises a negative photo-resist.

### Claim 17 (depends on 16)

The device of claim 16, wherein the negative photo-resist comprises:
an epoxy resin;
a gamma butyrolactone; and
a triaryl sulfonium salt.

### Claim 18 (depends on 12)

The device of claim 12, further comprising:
a printing fluid channel in a side of the molding opposite to a side of the molding containing the printhead die and the printed circuit assembly.

### Claim 19

A method, comprising:
applying a conductive layer between a printhead die and a printed circuit assembly embedded in a molding of a printhead via a shadow mask process to form an electrical interconnect; and
applying a dielectric layer over the electrical interconnect as a dry film laminate.

### Claim 20 (depends on 19)

The method of claim 19, wherein the shadow mask process comprises:
placing a shadow mask over the printhead to cover a nozzle portion of the printhead die and at least a portion of the printed circuit assembly; and
applying the conductive material via an evaporation or a sputtering to form the electrical interconnect in a region of the printhead defined by an open portion of the shadow mask.