Light emitting diode package structure

Abstract

A LED package structure including a carrier substrate, a flip-chip LED and a molding compound is provided. The carrier substrate includes a main body and a patterned conductive layer embedded in the main body. The main body is composed of polymer material. The main body has a cavity, and a bottom surface of the cavity is aligned with an upper surface of the patterned conductive layer. A difference in coefficient of thermal expansion between the main body in a rubbery state and the patterned conductive layer is smaller than 30 ppm/° C. The flip-chip LED is disposed inside the cavity and electrically connected to the patterned conductive layer. The molding compound is disposed inside the cavity and encapsulates the flip-chip LED. A vertical distance between a top surface of the molding compound and the bottom surface of the cavity is smaller than or equal to a depth of the cavity.

What is claimed is: 
     
         1 . A light emitting diode package structure, comprising:
 a carrier substrate, comprising a main body and a patterned conductive layer embedded in the main body, the main body being composed of a polymer material, and the main body having a cavity, and a bottom surface of the cavity being aligned with an upper surface of the patterned conductive layer, wherein a difference in coefficient of thermal expansion between the main body in a rubbery state and the patterned conductive layer is smaller than 30 ppm/° C.;   a flip-chip light emitting diode, disposed inside the cavity of the carrier substrate, and straddling the patterned conductive layer, and   a molding compound, disposed inside the cavity of the carrier substrate, and encapsulating the flip-chip light emitting diode.   
     
     
         2 . The light emitting diode package structure as claimed in  claim 1 , wherein the flip-chip light emitting diode and the patterned conductive layer are electrically connected through eutectic bonding. 
     
     
         3 . The light emitting diode package structure as claimed in  claim 1 , wherein a difference in coefficient of thermal expansion between the main body in the rubbery state and the main body in a glassy state is smaller than 35 ppm/° C. 
     
     
         4 . The light emitting diode package structure as claimed in  claim 1 , wherein a sidewall of the cavity surrounds the bottom surface, and the bottom surface and the sidewall include an included angle, wherein the included angle ranges between 95 degrees and 170 degrees. 
     
     
         5 . The light emitting diode package structure as claimed in  claim 1 , wherein vertical height between a top surface of the molding compound and the upper surface of the patterned conductive layer is 0.15 to 0.25 times of a straight-line distance from a center point of the bottom surface to an edge of the bottom surface of the cavity. 
     
     
         6 . The light emitting diode package structure as claimed in  claim 1 , wherein the molding compound is doped with a fluorescent material, and the fluorescent material comprises a yellow fluorescent powder, a red fluorescent powder, a green fluorescent powder, a blue fluorescent powder or a yttrium aluminum garnet fluorescent powder. 
     
     
         7 . The light emitting diode package structure as claimed in  claim 6 , wherein a weight percentage concentration of the fluorescent material in the molding compound ranges between 20% and 40%. 
     
     
         8 . The light emitting diode package structure as claimed in  claim 1 , wherein a vertical distance between a top surface of the molding compound at a center point and the bottom surface of the cavity is smaller than a depth of the cavity. 
     
     
         9 . A light emitting diode package structure, comprising:
 a carrier substrate, comprising a main body and at least two conductive leadframes embedded in the main body and spaced by a portion of the main body, the main body being composed of a polymer material and having a cavity exposing the conductive leadframes, wherein a difference in coefficient of thermal expansion between the main body in a rubbery state and the conductive leadframes is smaller than 30 ppm/° C.;   a flip-chip light emitting diode, disposed over the conductive leadframes and two electrodes of the flip-chip light emitting diode electrically bridging the conductive leadframes;   a fluorescent material dispersed over the flip-chip light emitting diode; and   a molding compound, disposed inside the cavity of the carrier substrate and encapsulating the flip-chip light emitting diode, wherein a level at a center of a top surface of the molding compound is lower than a level of an upper edge of the cavity.   
     
     
         10 . The light emitting diode package structure as claimed in  claim 9 , wherein the electrodes of the flip-chip light emitting diode are coupled to the conductive leadframes through eutectic bonding. 
     
     
         11 . The light emitting diode package structure as claimed in  claim 9 , wherein a difference in coefficient of thermal expansion between the main body in the rubbery state and the main body in a glassy state is smaller than 35 ppm/° C. 
     
     
         12 . The light emitting diode package structure as claimed in  claim 9 , wherein a sidewall and a bottom surface of the cavity include an included angle, wherein the included angle ranges between 95 degrees and 170 degrees. 
     
     
         13 . The light emitting diode package structure as claimed in  claim 9 , wherein a thickness of the molding compound is 0.15 to 0.25 times of a distance from a center of a bottom of the cavity to an edge thereof. 
     
     
         14 . The light emitting diode package structure as claimed in  claim 9 , wherein the fluorescent material dispersed in the molding compound has a weight percentage concentration ranging between 20% and 40%. 
     
     
         15 . A light emitting diode package structure, comprising:
 at least two conductive leadframes, spaced from each other,   a resin member, uniting the conductive leadframes and exposing portions of the conductive leadframes, wherein a difference in coefficient of thermal expansion between the resin member in a rubbery state and the conductive leadframes is smaller than 30 ppm/° C.; and   at least one light emitting diode, electrically connected to the conductive leadframes.   
     
     
         16 . The light emitting diode package structure as claimed in  claim 15 , wherein the resin member comprises an epoxy resin or a siloxane compound. 
     
     
         17 . The light emitting diode package structure as claimed in  claim 15 , wherein a difference in coefficient of thermal expansion between the resin member in the rubbery state and the resin member in a glassy state is smaller than 35 ppm/° C. 
     
     
         18 . The light emitting diode package structure as claimed in  claim 15 , further comprising a wavelength conversion member covering the light emitting diode. 
     
     
         19 . The light emitting diode package structure as claimed in  claim 18 , wherein the resin member has a cavity to accommodate the light emitting diode and the wavelength conversion member, wherein the cavity has an inclined sidewall in an angle ranging between 95 degrees and 170 degrees. 
     
     
         20 . The light emitting diode package structure as claimed in  claim 19 , wherein a height of the wavelength conversion member at a center is below a height of the inclined sidewall of the cavity.