Fluid ejection device with break(s) in cover layer

Patent metadata

Field	Value
Publication number	US-11745507-B2
Application number	US-201917311593-A
Country	US
Kind code	B2
Filing date	Apr 29, 2019
Priority date	Apr 29, 2019
Publication date	Sep 5, 2023
Grant date	Sep 5, 2023

Abstract

In various examples, a fluid ejection device may include a fluid ejection die formed with a first material and that includes a bondpad and a plurality of fluid ejectors, and a cover layer adjacent the fluid ejection die. The cover may be formed with a second material that is different than the first material and may include a first region that overlays the bondpad and a second region that overlays the plurality of fluid ejectors. In various examples, the first and second regions are separated by a break in the cover layer. The break may be filled with a third material that is different than one or both of the first and second material.

First claim

What is claimed is:

1. A fluid ejection device, comprising:
a fluid ejection die formed with a first material and that includes a bondpad and a plurality of fluid ejectors;
a cover layer adjacent the fluid ejection die and formed with a second material that is different than the first material, wherein the cover layer includes a first region that includes the bondpad and a second region, separate from the first region, that includes the plurality of fluid ejectors, wherein the first and second regions are separated by a break in the cover layer; and
a third material that is different than one or both of the first and second material, wherein the third material fills the break separating the first and second regions of the cover layer.

2. The fluid ejection device of claim 1 , wherein the cover layer comprises a plurality of sublayers constructed with the first material.

3. The fluid ejection device of claim 2 , wherein the break between the first and second regions comprises a break in top hat and chamber sublayers of the plurality of sublayers.

4. The fluid ejection device of claim 1 , wherein the first region of the cover layer comprises a wall formed with the second material that surrounds and prevents fluid from contacting the bondpad.

5. The fluid ejection device of claim 1 , wherein the second material comprises SU-8.

6. The fluid ejection device of claim 5 , wherein the third material comprises an epoxy mold compound (“EMC”).

7. The fluid ejection device of claim 6 , wherein the first material comprises silicon.

8. The fluid ejection device of claim 1 , wherein the fluid ejection die comprises a die sliver.

9. A printbar, comprising:
a printhead mounted to the printbar, the printhead including:
a die sliver that includes a bondpad and a plurality of fluid ejectors;
a photoresist layer adjacent the die sliver, wherein the photoresist layer includes a bondpad protection portion surrounding the bondpad and an orifice portion, separate from the bondpad protection portion, including the plurality of fluid ejectors and separated from the bondpad protection portion by a break in the photoresist layer; and
an epoxy mold compound (“EMC”) that fills the break separating the bondpad protection and orifice portions of the photoresist layer.

10. The printbar of claim 9 , wherein the photoresist layer is comprised of a negative photoresist.

11. The printbar of claim 9 , wherein the photoresist layer comprises a plurality of sublayers.

12. The printbar of claim 11 , wherein the break between the bondpad protection and orifice portions comprises a break in top hat and chamber sublayers of the plurality of sublayers.

13. The printbar of claim 9 , wherein the bondpad protection portion of the photoresist layer comprises a wall that surrounds and prevents fluid from contacting the bondpad.

14. A method for making a fluid ejection device, comprising:
applying a cover layer to a surface of a fluid ejection die so that a bondpad protection region of the cover layer includes a bondpad of the fluid ejection die and an orifice region, separate from the bondpad protection region, of the cover layer includes a plurality of fluid ejectors of the fluid ejection die;
forming a break in the cover layer between the bondpad protection and orifice regions of the cover layer; and
filling the break between the bondpad protection and orifice regions of the cover layer with a mold compound.

15. The method of claim 14 , wherein the cover layer comprises SU-8, and the applying comprises:
applying a continuous layer of SU-8 to the surface of the fluid ejection die; and
applying a mask to the continuous layer of SU-8, wherein the mask is shaped to allow light to pass to a first part of the continuous layer of SU-8 and to block light from reaching a second part of the continuous layer of SU-8.

Assignees

• Hewlett Packard Development Co

Inventors

• Cumbie Michael W
• Fuller Anthony M
• Chen Chien-Hua

Classifications

• B41J2/1433 Primary

  Structure of nozzle plates · CPC title

• B41J2/162

  Manufacturing of the nozzle plates · CPC title

• B41J2/1637

  molding · CPC title

• B41J2/14072 Primary

  Electrical connections, e.g. details on electrodes, connecting the chip to the outside... · CPC title

• B41J2/1603

  of the front shooter type · CPC title