Method for coating semiconductor device using droplet deposition

• US 8,390,016 B2
• Filed: 09/20/2011
• Issued: 03/05/2013
• Est. Priority Date: 01/09/2006
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Keller, Bernd, Loh, Ban P.
• Primary Examiner(s): Picardat, Kevin M
• Application Number:
  US13/237,789
• Publication Number:
  US 20120007126A1
• Time in Patent Office: 532 Days
• Field of Search: 257/88, 257/89, 257/91, 257/98, 257/99, 257/100
• US Class Current: 257/98
• CPC Class Codes: B41J 3/407 for marking on special material
• CPC Class Codes: H01L 21/6715 Apparatus for applying a liquid, a resin, an ink or the like H01L21/67126 takes precedence
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil

Abstract

Methods and systems for coating of semiconductor devices using droplets of wavelength conversion or phosphor particles in a liquid medium. A plurality of nozzles delivers a controlled amount of the matrix material to the surface of the semiconductor device, with each of said nozzles having an opening for the matrix material to pass. The opening has a diameter wherein the diameter of the phosphor particles is less than or approximately equal to one half the diameter of the opening. The phosphor particles are also substantially spherical or rounded. The nozzles are typically arranged on a print head that utilizes jet printing techniques to cover the semiconductor device with a layer of the matrix material. The methods and systems are particularly applicable to covering LEDs with a layer of phosphor materials.

Claims

1. A light emitter package, comprising:

a solid state emitter having a plurality of semiconductor layers, said solid state emitter emitting light in response to an electrical bias; and

a layer of phosphor material covering at least a portion of said solid state emitter, said layer of phosphor material comprising substantially rounded conversion particles deposited on said solid state emitter through a print head nozzle, such that gravity and surface tension cause said phosphor material to form a conformal coating on at least a portion of said solid state emitter, wherein said layer of phosphor material down-converts the wavelength of at least some of said emitter light.

2. The light emitter package of claim 1, wherein said solid state emitter comprises a light emitting diode (LED).

3. The light emitter package of claim 1, wherein said conversion particles are deposited on said solid state emitter in a liquid medium.

4. The light emitter package of claim 1, wherein said phosphor material down-converts the wavelength of less than all of said emitter light, said light emitter package emitting a combination of light from said solid state emitter and phosphor material.

5. A light emitter package, comprising:

a solid state emitter having a plurality of semiconductor layers, said solid state emitter emitting light in response to an electrical bias; and

a layer of phosphor material covering at least a portion of said solid state emitter, said layer of phosphor material comprising substantially rounded conversion particles deposited on said solid state emitter through a print head nozzle, such that gravity and surface tension cause said phosphor material to form a conformal coating on at least a portion of said solid state emitter, said print head nozzle having an opening wherein the diameter of said conversion particles is less than or approximately equal to half the diameter of said opening, said layer of phosphor material absorbing and down converting at least some of said emitter light.

6. The light emitter package of claim 5, wherein said solid state emitter comprises a light emitting diode (LED).

7. The light emitter package of claim 5, wherein said conversion particles are deposited on said solid state emitter in a liquid medium.

8. The light emitter package of claim 5, wherein said phosphor material down-converts the wavelength of less than all of said emitter light, said package emitting a combination of light from said solid state emitter and phosphor material.