Wafer level packaging of multiple light emitting diodes (leds) on a single carrier die

Abstract

An LED wafer includes LED dies on an LED substrate. The LED wafer and a carrier wafer are joined. The LED wafer that is joined to the carrier wafer is shaped. Wavelength conversion material is applied to the LED wafer that is shaped. Singulation is performed to provide multiple LED dies that are joined to a single carrier die. The multiple LED dies on the single carrier die are connected in series and/or in parallel by interconnection in the LED dies and/or in the single carrier die. The singulated devices may be mounted in an LED fixture to provide high light output per unit area. Related devices and fabrication methods are described.

What is claimed is: 
     
         1 . A lighting device comprising:
 a substrate comprising an inner face, an outer face opposing the inner face, and a thickness;   an array of LEDs supported by the substrate proximate to the inner face, wherein the array of LEDs comprises a plurality of anode contacts and a plurality of cathode contacts in conductive electrical communication with the array of LEDs, and the array of LEDs is arranged to transmit LED emissions through the substrate to exit the outer face;   a carrier comprising a plurality of anode pads in conductive electrical communication with the plurality of anode contacts, and comprising a plurality of cathode pads in conductive electrical communication with the plurality of cathode contacts; and   a plurality of reflective features;   wherein the array of LEDs is arranged between the substrate and the carrier; and   wherein at least a portion of each reflective feature of the plurality of reflective features is arranged between different LEDs of the array of LEDs.   
     
     
         2 . The lighting device of  claim 1 , further comprising a plurality of trenches defined in the inner face of the substrate, wherein the at least a portion of each reflective feature of the plurality of reflective features extends into a different trench of the plurality of trenches. 
     
     
         3 . The lighting device of  claim 1 , wherein the plurality of reflective features is embodied in at least one internal interconnection layer. 
     
     
         4 . The lighting device of  claim 1 , further comprising a plurality of recesses formed in the substrate, wherein each recess of the plurality of recesses extends from the outer face in a direction toward the inner face, and each recess is substantially registered with a boundary between adjacent LEDs of the array of LEDs. 
     
     
         5 . The lighting device of  claim 4 , wherein each recess of the plurality of recesses extends through less than an entirety of the thickness of the substrate. 
     
     
         6 . The lighting device of  claim 1 , further comprising a wavelength conversion material arranged on or over the outer face of the substrate. 
     
     
         7 . The lighting device of  claim 6 , further comprising a protective layer that is devoid of wavelength conversion material and that is arranged over the wavelength conversion material. 
     
     
         8 . The lighting device of  claim 1 , wherein the outer face of the substrate comprises textural features. 
     
     
         9 . The lighting device of  claim 8 , further comprising a wavelength conversion material arranged on or over the textural features of the outer face of the substrate. 
     
     
         10 . The lighting device of  claim 1 , wherein the substrate comprises a growth substrate on which epitaxial layers forming the array of LEDs were grown. 
     
     
         11 . The lighting device of  claim 1 , further comprising an insulating material arranged between the array of LEDs and the plurality of reflective features. 
     
     
         12 . The lighting device of  claim 1 , wherein the plurality of reflective features comprises at least one metal. 
     
     
         13 . The lighting device of  claim 1 , wherein the carrier comprises at least one reflector structure configured to reflect emissions of the plurality of LEDs toward the outer face of the substrate. 
     
     
         14 . The lighting device of  claim 1 , wherein the plurality of anode contacts and the plurality of cathode contacts are substantially coplanar. 
     
     
         15 . The lighting device of  claim 1 , further comprising a housing, wherein the lighting device is devoid of a dome between the array of LEDs and the housing. 
     
     
         16 . The lighting device of  claim 1 , wherein:
 the carrier comprises an inner surface and an outer surface that opposes the inner surface;   the plurality of anode pads and the plurality of cathode pads are arranged on or along the inner surface; and   the carrier further comprises a plurality of device anodes and a plurality of device cathodes arranged on or along the outer surface.   
     
     
         17 . The lighting device of  claim 1 , wherein each LED of the array of LEDs comprises a flip-chip configuration. 
     
     
         18 . A method for fabricating a lighting device, the method comprising:
 growing epitaxial layers over an inner face of a growth substrate and defining a plurality of trenches in the epitaxial layers to produce an array of LEDs;   providing a plurality of anode contacts and a plurality of cathode contacts in conductive electrical communication with the array of LEDs;   forming a plurality of reflective features in the plurality of trenches; and   mounting the array of LEDs over a carrier, including establishing conductive electrical communication between the plurality of anode contacts and a plurality of anode pads of the carrier, and establishing conductive electrical communication between the plurality of cathode contacts and a plurality of cathode pads of the carrier.   
     
     
         19 . The method of  claim 18 , further comprising thinning the growth substrate after said growing of the epitaxial layers. 
     
     
         20 . The method of  claim 18 , wherein the growth substrate further comprises an outer face that opposes the inner face, and the method further comprises defining a plurality of recesses in the growth substrate in a direction extending from the outer face toward the inner face. 
     
     
         21 . The method of  claim 18 , wherein the growth substrate further comprises an outer face that opposes the inner face, and the method further comprises depositing a wavelength conversion material on or over the outer face. 
     
     
         22 . The method of  claim 18 , further comprising forming at least one insulating layer in the plurality of trenches prior to said forming of the plurality of reflective features in the plurality of trenches.