Inkjet printhead with encapsulant-retaining features

Patent metadata

Field	Value
Publication number	US-2019337291-A1
Application number	US-201916400949-A
Country	US
Kind code	A1
Filing date	May 1, 2019
Priority date	May 3, 2018
Publication date	Nov 7, 2019
Grant date	—

Abstract

A MEMS chip assembly including: a support structure having a chip mounting surface; a MEMS chip mounted on the chip mounting surface, each MEMS chip having an active surface including one or more MEMS devices and a plurality of bond pads disposed alongside a connection edge of the MEMS chip; electrical connectors connected to the bond pads; and an encapsulant material covering the electrical connectors. The MEMS chip has encapsulant-retaining trenches defined in the active surface extending alongside the connection edge, each encapsulant-retaining trench being disposed between the bond pads and the MEMS devices.

First claim

1 . A MEMS chip assembly comprising:
a support structure having a chip mounting surface; a MEMS chip mounted on the chip mounting surface, each MEMS chip having an active surface including one or more MEMS devices and a plurality of bond pads disposed alongside a connection edge of the MEMS chip; electrical connectors connected to the bond pads; and an encapsulant material covering the electrical connectors,
wherein the MEMS chip has one or more encapsulant-retaining trenches defined in the active surface extending alongside the connection edge, each encapsulant-retaining trench being disposed between the bond pads and the MEMS devices,
and wherein the encapsulant material does not encroach past the encapsulant-retaining trenches towards the MEMS devices.

2 . The MEMS chip assembly of claim 1 , wherein the electrical connectors comprise wirebonds or TAB connections.

3 . The MEMS chip assembly of claim 1 , wherein multiple rows of encapsulant-retaining trenches are disposed between the bond pads and the MEMS devices.

4 . The MEMS chip assembly of claim 2 , wherein the rows of encapsulant-retaining trenches extend parallel with the connection edge.

5 . The MEMS chip assembly of claim 1 , wherein each encapsulant-retaining trench has a depth in the range of 2 to 10 microns and a width in the range of 2 to 20 microns.

6 . The MEMS chip assembly of claim 1 , wherein each encapsulant-retaining trench has a rectangular profile in cross-section.

7 . The MEMS chip assembly of claim 1 , wherein the encapsulant material does not encroach beyond the encapsulant-retaining trenches towards the MEMS devices.

8 . The MEMS chip assembly of claim 1 , wherein the encapsulant material is a polymer applied as a liquid during encapsulation.

9 . The MEMS chip assembly of claim 1 , wherein the MEMS devices are inkjet nozzle devices and the support structure is a fluid manifold for delivering ink to the inkjet nozzle devices.

10 . A MEMS chip comprising a substrate having an active surface, the active surface including a plurality of MEMS devices, a plurality of bond pads arranged alongside a connection edge of the substrate and one or more encapsulant-retaining trenches defined therein, wherein the encapsulant-retaining trenches extend alongside the connection edge and each encapsulant-retaining trench is disposed between the bond pads and the MEMS devices.

11 . The MEMS chip of claim 10 , wherein multiple rows of encapsulant-retaining trenches are disposed between the bond pads and the MEMS devices.

12 . The MEMS chip of claim 10 , wherein the rows of encapsulant-retaining trenches extend parallel with the connection edge.

13 . The MEMS chip of claim 10 , wherein each encapsulant-retaining trench has a depth in the range of 2 to 10 microns and a width in the range of 2 to 20 microns.

14 . The MEMS chip of claim 10 , wherein the MEMS devices are inkjet nozzle devices.

15 . A method of fabricating a MEMS chip assembly, said method comprising the steps of:
mounting a MEMS chip to a chip mounting surface of a support structure, each MEMS chip comprising a substrate having an active surface, the active surface including a plurality of MEMS devices, a plurality of bond pads arranged alongside a connection edge of the substrate and one or more encapsulant-retaining trenches defined therein, wherein the encapsulant-retaining trenches extend alongside the connection edge and each encapsulant-retaining trench is disposed between the bond pads and the MEMS devices; connecting electrical connectors to the plurality of bond pads; applying one or more beads of liquid encapsulant material over the electrical connectors; pinning an advancing liquid front of the encapsulant material at an edge of one of the encapsulant-retaining trenches defined in the active surface; and curing the encapsulant material.

16 . The method of claim 15 , wherein the encapsulant-retaining trench minimizes encroachment of the encapsulant material onto the MEMS devices.

17 . The method of claim 15 , wherein the encapsulant material is a liquid polymer.

18 . The method of claim 15 , wherein the encapsulant-retaining trench extends parallel with a longitudinal edge of the MEMS chip.

19 . The method of claim 15 , wherein the MEMS chip is a printhead chip and the MEMS chip assembly is an inkjet printhead.

Assignees

• Memjet Technology Ltd

Inventors

• Perez Elmer Dimaculangan
• North Angus
• Lowe Graeme
• Tan See-Huat
• Barton Christopher

Classifications

• B41J2202/15

  Moving nozzle or nozzle plate · CPC title

• B81B7/0032

  Packages or encapsulation (processes for packaging MEMS B81C1/00261; packaging of smart-MEMS B81C1/0023) · CPC title

• B41J2/145 Primary

  Arrangement thereof · CPC title

• B81B2201/052

  Ink-jet print cartridges · CPC title

• B41J2202/20

  Modules · CPC title