Semiconductor Light Emitting Device Packages and Methods

Abstract

A submount for a light emitting device package includes a substrate with a first bond pad and a second bond pad on a first surface. The first bond pad includes a die attach region offset toward a first end of the substrate and configured to receive a light emitting diode. The second bond pad includes a bonding region between the first bond pad and the second end of the substrate and a second bond pad extension that extends from the bonding region along a side of the substrate toward a corner of the substrate at the first end of the substrate. First and second solder pads are on the second surface of the substrate. The first solder pad is adjacent the first end of the substrate and contacts the second bond pad. The second solder pad is adjacent the second end of the substrate and contacts the first bond pad.

That which is claimed is: 
     
         1 . A method of forming a plurality of packaged light emitting diodes, comprising:
 providing a sheet of ceramic material including a two-dimensional array of light emitting devices mounted thereon;   providing a mold including a plurality of cavities therein;   dispensing a liquid encapsulant material in respective ones of the plurality of cavities;   bringing the sheet of ceramic material into contact with the mold so that respective ones of the light emitting devices extend into a corresponding one of the plurality of cavities; and   at least partially curing the liquid encapsulant so as to form encapsulant coatings around the respective light emitting devices.   
     
     
         2 . The method of  claim 1 , further comprising separating the sheet of ceramic material from the mold leaving the encapsulant coatings around the respective light emitting devices. 
     
     
         3 . The method of  claim 2 , wherein the mold comprises a plurality of sidewalls between ones of the plurality of cavities, and wherein bringing the sheet of ceramic material into contact with the mold comprises bringing the sheet of ceramic material into contact with top surfaces of ones of the plurality of sidewalls. 
     
     
         4 . The method of  claim 3 , further comprising preventing ones of the encapsulated coatings from contacting adjacent ones of the encapsulated coatings. 
     
     
         5 . The method of  claim 3 , further comprising forming a plurality of metallized holes in the sheet of ceramic material, and wherein bringing the sheet of ceramic material into contact with the mold comprises aligning ones of the plurality of metallized holes with ones of the plurality of sidewalls. 
     
     
         6 . The method of  claim 5 , further comprising separating the sheet of ceramic material along separation lines that extend through a subset of the plurality of metallized holes to thereby define individual light emitting diode substrates. 
     
     
         7 . The method of  claim 6 , wherein the plurality of metallized holes are arranged in a lattice of rectangular patterns on the sheet of ceramic material such that ones of the plurality of metallized holes are placed at corners of the rectangular patterns, and wherein the rectangular patterns define the individual light emitting diode substrates upon separation. 
     
     
         8 . The method of  claim 7 , wherein the plurality of metallized holes form castellations at the corners of the rectangular patterns upon separation, the castellations comprising respective electrical vies thereon extending from first surfaces of the individual light emitting diode substrates to second surfaces of the individual light emitting diode substrates opposite the first surfaces. 
     
     
         9 . The method of  claim 8 , wherein the castellations of each individual light emitting diode substrate are at opposite corners of the substrate. 
     
     
         10 . The method of  claim 7 , wherein the plurality of metallized holes comprises square holes. 
     
     
         11 . The method of  claim 7 , wherein the plurality of metallized holes comprises circular holes. 
     
     
         12 . The method of  claim 1 , further comprising:
 forming holes at corners of the sheet of ceramic material;   forming holes at edges of the sheet of ceramic material; and   aligning the sheet of ceramic material during the bringing using the holes at the corners and the edges of the sheet of ceramic material.   
     
     
         13 . The method of  claim 12 , wherein forming holes at the corners of the sheet of ceramic material comprises forming  114  circle holes and forming holes at the edges of the sheet of ceramic material comprises forming ½ circle holes. 
     
     
         14 . The method of  claim 1 , wherein ones of the plurality of cavities comprise lens molding surfaces shaped to mold the liquid encapsulant material into specified lens shapes at specified locations on the sheet of ceramic material. 
     
     
         15 . A method of forming a plurality of packaged light emitting diodes, comprising:
 forming a plurality of light emitting devices on a sheet of ceramic material;   molding liquid encapsulant over ones of the plurality of light emitting devices;   partially curing the liquid encapsulant so as to form encapsulant coatings around the respective light emitting devices; and   separating the sheet of ceramic material to thereby define individual light emitting diode substrates.   
     
     
         16 . The method of  claim 15 , further comprising forming a plurality of metallized holes in the sheet of ceramic material, and wherein separating comprises separating the sheet of ceramic material along separation lines that extend through a subset of the plurality of metallized holes. 
     
     
         17 . A method of forming a submount for a light emitting diode (LED) package, comprising:
 providing a substrate having a first surface and a second surface opposite the first surface, a first end and a second end opposite the first end, a first corner at the first end and a second corner at the second end and diagonally across the substrate from the first corner;   forming a seed layer on the first surface of the substrate;   patterning the seed layer to form a first bond pad pattern and a second bond pad pattern on the first surface of the substrate;   forming a first bond pad on the first bond pad pattern, wherein the first bond pad includes a die attach region offset from a center of the first surface toward the first end of the substrate and configured to receive a light emitting diode thereon;   forming a second bond pad on the second bond pad pattern, wherein the second bond pad includes a bonding region that is between the first bond pad and the second end of the substrate and a second bond pad extension that continuously extends from the bonding region of the second bond pad along a side of the first surface of the substrate toward a corner of the substrate at the first end of the substrate; and   etching the first bond pad and the second bond pad to increase a separation between the first bond pad and the second bond pad.   
     
     
         18 . The method of  claim 17 , further comprising forming first and second solder pads on the second surface of the substrate, wherein the first solder pad is adjacent the first end of the substrate and the second solder pad is adjacent the second end of the substrate, and wherein the second bond pad is in electrical contact with the first solder pad and the first bond pad is in electrical contact with the second solder pad. 
     
     
         19 . The method of  claim 17 , further comprising:
 forming a thermal spreading layer on the seed layer, wherein the thermal spreading layer comprises a layer of copper having a thickness greater than about 5 μm; and   forming a first barrier layer comprising nickel on the thermal spreading layer opposite the seed layer and a second barrier layer comprising nickel between the seed layer and the thermal spreading layer.   
     
     
         20 . The method of  claim 19 , further comprising:
 forming a reflective layer on the barrier layer opposite the thermal spreading layer.