# US 10,864,733 B2 · Inkjet printhead with encapsulant-retaining features > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,864,733 B2 - Document ID: US10864733B2 - Status: Granted - Kind: B2 - Application number: 16/400,949 - Filed: 2019-05-01 - Published: 2019-11-07 - Granted: 2020-12-15 - Earliest claimed: 2018-05-03 - Assignees: Memjet Technology Limited - Applicants: Memjet Technology Limited - Inventors: Elmer Dimaculangan Perez; Angus North; Graeme Lowe; See-Huat Tan; Christopher Barton - Web page: https://patentgrep.com/patent/US10864733B2 ## CPC - B41J 2/14427: {Structure of ink jet print heads with thermal bend detached actuators} - B41J 2/145: Arrangement thereof - B41J 2/04541: {Specific driving circuit} - B41J 2/14024: {Assembling head parts} - B41J 2/14072: {Electrical connections, e.g. details on electrodes, connecting the chip to the outside...} - B41J 2/1601: {Production of bubble jet print heads (B41J2/1606, B41J2/162 take precedence)} - B81B 7/0032: {Packages or encapsulation (processes for packaging MEMS B81C1/00261; packaging of smart-MEMS B81C1/0023)} - B41J 2002/14491: {Electrical connection} - B41J 2202/15: Moving nozzle or nozzle plate - B41J 2202/20: Modules - B81B 2201/052: Ink-jet print cartridges - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00) ## 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. ## Claims ### 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 rows of MEMS devices and a row of bond pads disposed alongside a connection edge of the MEMS chip and parallel with the rows of MEMS devices; electrical connectors connected to the bond pads; and an encapsulant material covering the electrical connectors, wherein: the MEMS chip has multiple rows of encapsulant-retaining trenches defined in the active surface; the multiple rows of encapsulant-retaining trenches extend parallel with the rows of MEMS devices; a distance between neighboring encapsulant-retaining trenches is greater than a width of each encapsulant-retaining trench; the multiple rows of encapsulant-retaining trenches are disposed between the bond pads and the MEMS devices; and the encapsulant material does not encroach past the encapsulant-retaining trenches towards the MEMS devices. ### Claim 2 (depends on 1) The MEMS chip assembly of claim 1, wherein the electrical connectors comprise wirebonds or TAB connections. ### Claim 3 (depends on 1) The MEMS chip assembly of claim 1, wherein the rows of encapsulant-retaining trenches extend parallel with the connection edge. ### Claim 4 (depends on 1) 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. ### Claim 5 (depends on 1) The MEMS chip assembly of claim 1, wherein each encapsulant-retaining trench has a rectangular profile in cross-section. ### Claim 6 (depends on 1) The MEMS chip assembly of claim 1, wherein the encapsulant material is a polymer applied as a liquid during encapsulation. ### Claim 7 (depends on 1) 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. ### Claim 8 A MEMS chip comprising a substrate having an active surface, the active surface including: a plurality of rows of MEMS devices; and a row of bond pads arranged alongside a connection edge of the substrate and parallel with the rows of MEMS devices; and wherein: the MEMS chip has multiple rows of encapsulant-retaining trenches defined in the active surface; the multiple rows of encapsulant-retaining trenches extend parallel with the rows of MEMS devices; a distance between neighboring encapsulant-retaining trenches is greater than a width of each encapsulant-retaining trench; and the multiple rows of encapsulant-retaining trenches are disposed between the bond pads and the MEMS devices. ### Claim 9 (depends on 8) The MEMS chip of claim 8, wherein the rows of encapsulant-retaining trenches extend parallel with the connection edge. ### Claim 10 (depends on 8) The MEMS chip of claim 8, 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. ### Claim 11 (depends on 8) The MEMS chip of claim 8, wherein the MEMS devices are inkjet nozzle devices. ### Claim 12 (depends on 8) A method of fabricating a MEMS chip assembly, said method comprising the steps of: mounting a MEMS chip according to claim 8 to a chip mounting surface of a support structure; connecting electrical connectors to the row 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. ### Claim 13 (depends on 12) The method of claim 12, wherein the multiple encapsulant-retaining trenches minimize encroachment of the encapsulant material onto the MEMS devices. ### Claim 14 (depends on 12) The method of claim 12, wherein the encapsulant material is a liquid polymer. ### Claim 15 (depends on 12) The method of claim 12, wherein the rows of encapsulant-retaining trenches extends parallel with a longitudinal edge of the MEMS chip. ### Claim 16 (depends on 12) The method of claim 12, wherein the MEMS chip is a printhead chip and the MEMS chip assembly is an inkjet printhead.