# US 12,119,432 B2 · Encapsulated light emitting diodes for selective fluidic assembly > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,119,432 B2 - Document ID: US12119432B2 - Status: Granted - Kind: B2 - Application number: 16/984,491 - Filed: 2020-08-04 - Published: 2020-11-19 - Granted: 2024-10-15 - Earliest claimed: 2014-10-31 - Assignees: eLux, Inc. - Applicants: eLux Inc. - Inventors: Kenji Sasaki; Paul J. Schuele - Web page: https://patentgrep.com/patent/US12119432B2 ## CPC - H10H 20/853: characterised by their shape - H10H 20/855: Optical field-shaping means, e.g. lenses - H10H 20/857: Interconnections, e.g. lead-frames, bond wires or solder balls - H10H 29/142: {Two-dimensional arrangements, e.g. asymmetric LED layout} - H10P 72/74: {using temporarily an auxiliary support} - H10W 72/0198: {batch processes} - H10W 74/014: {using batch processing} - H10W 74/141: {the encapsulations being on at least the sidewalls of the semiconductor body} - H10W 90/00: Package configurations - H10H 20/018: {Bonding of wafers} - H10H 20/0362: {of encapsulations} - H10H 20/819: characterised by their shape, e.g. curved or truncated substrates - H10H 20/825: containing nitrogen, e.g. GaN - H10H 20/856: Reflecting means - H10P 72/7426: {used as a support during build up manufacturing of active devices} - H10P 72/7428: {used to support diced chips prior to mounting} - H10P 72/7432: {used in a transfer process involving transfer directly from an origin substrate to a target substrate without use of an intermediate handle substrate} - H10P 72/7434: {used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate} - H10W 70/682: {comprising holes having chips therein} - H10W 72/012: {of bump connectors, dummy bumps or thermal bumps} - H10W 72/019: {of bond pads} - H10W 72/072: {of bump connectors} - H10W 72/20: Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps - H10W 72/9413: {on encapsulations} - H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract A method is provided for fabricating an encapsulated emissive element. Beginning with a growth substrate, a plurality of emissive elements is formed. The growth substrate top surface is conformally coated with an encapsulation material. The encapsulation material may be photoresist, a polymer, a light reflective material, or a light absorbing material. The encapsulant is patterned to form fluidic assembly keys having a profile differing from the emissive element profiles. In one aspect, prior to separating the emissive elements from the handling substrate, a fluidic assembly keel or post is formed on each emissive element bottom surface. In one variation, the emissive elements have a horizontal profile. The fluidic assembly key has horizontal profile differing from the emissive element horizontal profile useful in selectively depositing different types of emissive elements during fluidic assembly. In another aspect, the emissive elements and fluidic assembly keys have differing vertical profiles useful in preventing detrapment. ## Claims ### Claim 1 An encapsulated emissive element for selective fluidic assembly comprising: a micro-light emitting diode (micro-LED) having a closed perimeter shape, as viewed from a horizontal plane top-down perspective, comprising a top surface, a bottom surface with a first length in the horizontal plane, sidewall surfaces with a first thickness less than the first length between the micro-LED top and bottom surfaces less than the first length, and a pair of electrical contacts with at least one electrical contact formed on the micro-LED top surface; and, a fluidic assembly key exposing the electrical contacts and exposing a second length portion of the micro-LED bottom surface, where the second length is greater than the first thickness, while at least partially encapsulating the micro-LED to form a closed perimeter shape, as viewed from the horizontal plane top-down perspective, different than the micro-LED closed perimeter shape. ### Claim 2 (depends on 1) The encapsulated emissive element of claim 1 further comprising: a plurality of micro-LED types, each micro-LED type configured to emit a unique wavelength of light; and, a plurality of fluidic assembly key types, each fluidic assembly key type associated with a corresponding micro-LED type, and having a unique closed perimeter shape. ### Claim 3 (depends on 1) The encapsulated emissive element of claim 1 further comprising: a plurality of micro-LED types, each micro-LED type configured to emit a unique wavelength of light; and, a plurality of fluidic assembly key types, each fluidic assembly key type associated with a corresponding micro-LED type, and having a different closed perimeter shape than the corresponding micro-LED type. ### Claim 4 (depends on 1) The encapsulated emissive element of claim 1 further comprising: a plurality of micro-LED types, each micro-LED type configured to emit a unique wavelength of light; and, a plurality of fluidic assembly key types, each fluidic assembly key type having a circular closed perimeter shape with a unique diameter. ### Claim 5 (depends on 1) The encapsulated emissive element of claim 1 further comprising: a plurality of micro-LED types, each micro-LED type having a unique closed perimeter shape and configured to emit a unique wavelength of light; and, a plurality of fluidic assembly key types, each fluidic assembly key type associated with a corresponding micro-LED type. ### Claim 6 (depends on 1) The encapsulated emissive element of claim 1 further comprising: a plurality of micro-LED types, each micro-LED type having a common closed perimeter shape and configured to emit a unique wavelength of light; and, a plurality of fluidic assembly key types, each fluidic assembly key type associated with a corresponding micro-LED type. ### Claim 7 (depends on 1) The encapsulated emissive element of claim 1 further comprising: a plurality of micro-LED types, each micro-LED type having a circular closed perimeter shape and configured to emit a unique wavelength of light; and, a plurality of fluidic assembly key types, each fluidic assembly key type associated with a corresponding micro-LED type. ### Claim 8 (depends on 1) The encapsulated emissive element of claim 1 wherein the micro-LED electrical contacts are arranged in an orientation selected from the group consisting of vertical, with a first electrical contact formed on the micro-LED top surface and a second electrical contact formed on the micro-LED bottom surface, and surface mount, with both the first and second electrical contacts formed on the micro-LED top surface. ### Claim 9 A fluidic assembly emissive display comprising: a substrate comprising: a top surface; a plurality of trap sites formed in the substrate top surface, with each trap site having sidewalls and an opening with a closed perimeter shape, as viewed from a horizontal plane top-down perspective, and a bottom surface with at least a first electrical interface connected to a corresponding intersection in an underlying row/column enablement matrix; an encapsulated emissive element occupying each trap site, each encapsulated emissive element comprising: a micro-light emitting diode (micro-LED) having a closed perimeter shape, as viewed from the horizontal plane top-down perspective, comprising a top surface, a bottom surface with a first length in the horizontal plane, sidewall surfaces with a first thickness less than the first length between the micro-LED top and bottom surfaces less than the first length, and a pair of electrical contacts with at least one electrical contact formed on the micro-LED top surface; a fluidic assembly key exposing the electrical contacts and exposing a second length portion of the micro-LED bottom surface, where the second length is greater than the first thickness, while at least partially encapsulating the micro-LED to form a closed perimeter shape, as viewed from the horizontal plane top-down perspective, matching the trap site opening closed perimeter shape; and, wherein the trap site openings reveal the micro-LED bottom surface exposed second lengths. ### Claim 10 (depends on 9) The emissive display of claim 9 wherein at least one fluidic assembly key type has a different closed perimeter shape than its corresponding micro-LED. ### Claim 11 (depends on 9) The emissive display of claim 9 wherein a plurality of fluidic assembly key types have a unique closed perimeter shape. ### Claim 12 (depends on 9) The emissive display of claim 9 wherein a plurality of fluidic assembly key types have a circular closed perimeter shape with a unique diameter. ### Claim 13 (depends on 9) The emissive display of claim 9 wherein a plurality of micro-LED types have a unique closed perimeter shape. ### Claim 14 (depends on 9) The emissive display of claim 9 wherein a plurality of micro-LED types have a common closed perimeter shape. ### Claim 15 (depends on 9) The emissive display of claim 9 wherein a plurality of micro-LED types have a circular closed perimeter shape. ### Claim 16 (depends on 9) The emissive display of claim 9 wherein the micro-LED electrical contacts are arranged in an orientation selected from the group consisting of vertical, with a first electrical contact formed on the micro-LED top surface and a second electrical contact formed on the micro-LED bottom surface, and surface mount, with both the first and second electrical contacts formed on the micro-LED top surface. ### Claim 17 An encapsulated emissive element for selective fluidic assembly comprising: a micro-light emitting diode (micro-LED) having a closed perimeter shape, as viewed from a horizontal plane top-down perspective, comprising a top surface, a bottom surface, sidewall surfaces between the micro-LED top and bottom surfaces, with a sidewall first profile as viewed from a vertical partial cross-sectional perspective, and a pair of electrical contacts with at least one electrical contact formed on the micro-LED top surface; and, a fluidic assembly key exposing the electrical contacts and at least a portion of the micro-LED bottom surface, while at least partially encapsulating the micro-LED to form a closed perimeter shape, as viewed from the horizontal plane top-down perspective, different than the micro-LED closed perimeter shape, with a second sidewall profile between fluidic assembly key top and bottom surfaces, as viewed from a vertical partial cross-sectional view perspective, formed independent of the first profile.