Flip-chip phosphor coating method and devices fabricated utilizing method

Abstract

Methods for fabricating light emitting diode (LED) chips one of which comprises flip-chip mounting a plurality of LEDs on a surface of a submount wafer and forming a coating over said LEDs. The coating comprising a conversion material at least partially covering the LEDs. The coating is planarized to the desired thickness with the coating being continuous and unobstructed on the top surface of the LEDs. The LEDs chips are then singulated from the submount wafer. An LED chip comprising a lateral geometry LED having first and second contacts, with the LED flip-chip mounted to a submount by a conductive bonding material. A phosphor loaded binder coats and at least partially covers the LED. The binder provides a substantially continuous and unobstructed coating over the LED. The phosphor within the coating absorbs and converts the wavelength of at least some of the LED light with the coating planarized to achieve the desired emission color point of the LED chip.

We claim: 
     
         1 . A light emitting diode (LED) chip wafer, comprising:
 a plurality of LEDs comprising contacts accessible at one side;   a phosphor loaded binder coating at least partially covering said LEDs and comprising substantially the same thickness over each of said LEDs and being continuous and unobstructed over each of said LEDs.   
     
     
         2 . The LED chip wafer of  claim 1 , wherein said plurality of LEDs are mounted to a metal lead frame and said contacts are accessible at said metal lead frame. 
     
     
         3 . The LED chip wafer of  claim 1 , wherein said plurality of LEDs are mounted to a submount wafer and said contacts are accessible at said submount wafer. 
     
     
         4 . The LED chip wafer of  claim 3 , further comprising conductive vias through said submount wafer, wherein each of said conductive vias is in electrical contact with one of said contact. 
     
     
         5 . The LED chip wafer of  claim 4 , further comprising a dielectric material insulating said conductive vias from said submount wafer. 
     
     
         6 . The LED chip wafer of  claim 1 , wherein at least one of said plurality of LEDs has a lateral geometry. 
     
     
         7 . The LED chip wafer of  claim 1 , wherein said at least some of said plurality of LED comprises oppositely doped layers with a mesa formed on one of said oppositely doped layers. 
     
     
         8 . The LED chip wafer of  claim 1 , wherein said contacts comprise first and second contacts, the first being on said mesa of one of said oppositely doped layers and the second being on the other of said oppositely doped layers. 
     
     
         9 . The LED chip wafer of  claim 1 , wherein at least some of said LEDs have a textured surface that comprises texture features larger than 10% of the thickness of said LED. 
     
     
         10 . The LED chip wafer of  claim 1 , wherein said submount wafer is capable of being separated into LED chips. 
     
     
         11 . The LED chip wafer of  claim 1 , wherein said coating has a uniform thickness above said LEDs. 
     
     
         12 . The LED chip wafer of  claim 1 , wherein said coating has a textured surface. 
     
     
         13 . The LED chip wafer of  claim 1 , wherein said coating comprises multiple phosphors. 
     
     
         14 . The LED chip wafer of  claim 1 , wherein said coating comprises scattering particles. 
     
     
         15 . The LED chip wafer of  claim 1 , wherein said LEDs are made of materials from the Group-III nitride material system. 
     
     
         16 . The LED chip wafer of  claim 1 , further comprising a temporary carrier. 
     
     
         17 . The LED chip wafer of  claim 1 , wherein said LEDs are interconnected in an LED array. 
     
     
         18 . The LED chip wafer of  claim 2 , further comprising an underfill material filling the spaces between said metal lead frame and said plurality of LED chips. 
     
     
         19 . The LED chip wafer of  claim 2 , further comprising a reflective layer formed on the same side of the plurality of LEDS as said metal lead frame. 
     
     
         20 . The LED chip wafer of  claim 1 , wherein said coating comprises multiple layers with different compositions. 
     
     
         21 . The LED chip wafer of  claim 1 , capable of emitting white light from said LEDs and coating. 
     
     
         22 . The LED chip wafer of  claim 1 , wherein said wafer is designed to be singulated into a plurality of LEDs, such that the light emitted from each of said singulated LEDs is substantially uniform, at least some of the light emitted from said LEDs passing through said coating where at least some of said LED light is wavelength-converted in said coating. 
     
     
         23 . A light emitting diode (LED) chip, comprising:
 a lateral geometry LED comprising first and second contacts;   a phosphor loaded binder coating on and covering a first surface of said LED, said phosphor within said coating absorbing and converting the wavelength of at least some of said LED light; and   wherein said first and second contacts are accessible from a surface opposite said first surface, said first and second contacts further comprising first and second leads for surface mounting.   
     
     
         24 . The LED chip of  claim 23 , wherein said first and second leads are capable of being surface mounted without an intervening submount. 
     
     
         25 . The LED chip of  claim 23 , further comprising an underfill material filling the spaces between said leads and said LED chip. 
     
     
         26 . The LED chip of  claim 23 , wherein said LED is capable of being flip-chip mounted to a submount by a conductive bonding material, such that said leads are in contact with said submount and an electrical signal is applied to said LED through said submount and said leads. 
     
     
         27 . The LED chip of  claim 26 , wherein said submount comprises electrically conductive vias electrically coupled to said contacts. 
     
     
         28 . The LED chip of  claim 27 , further comprising a dielectric material insulating said conductive vias from said submount. 
     
     
         29 . The LED chip of  claim 27 , wherein said conductive vias permit an electrical signal to be applied to said LED through said submount. 
     
     
         30 . The LED chip of  claim 27 , wherein said submount comprises surface mount leads. 
     
     
         31 . The LED chip of  claim 23 , wherein said phosphor coating is continuous over the top surface of said LED and has a substantially uniform thickness. 
     
     
         32 . The LED chip of  claim 23 , wherein said LED chip is adapted to emit a white light combination of LED light and light from said phosphor. 
     
     
         33 . The LED chip of  claim 23 , wherein said phosphor loaded binder coating is on and covering a side surface of said LED. 
     
     
         34 . The LED chip of  claim 23 , wherein said first surface comprises a substrate.