Integrated circuit package with transparent encapsulant and method for making thereof

Abstract

IC package with transparent encapsulant and method for making thereof. The IC package includes a die pad including a pad bottom surface, a die disposed on the die pad and including an integrated circuit, a plurality of leads including a plurality of lead bottom surfaces, a plurality of conductive wires connecting the die and the plurality of leads, and an encapsulant material. The encapsulant material is transparent for visible wavelengths. The pad bottom surface is exposed without being covered by the encapsulant material, and the plurality of lead bottom surfaces each are exposed without being covered by the encapsulant material.

1 . A method for making an IC package with transparent encapsulant, the method comprising: 
 providing a leadframe, the leadframe including a first die pad and a second die pad;    disposing a first die on the first die pad and a second die on the second die pad;    forming a cavity on the leadframe, the cavity including the first die pad and the second die pad;    injecting an encapsulant material into the cavity;    cutting the injected encapsulant material and the leadframe to form a first IC package and a second IC package;    wherein: 
 the encapsulant material is transparent for visible wavelengths; and  
 the injecting an encapsulant material is performed at an encapsulant temperature ranging from 140° c to 160° c.  
   
     
     
         2 . The method of  claim 1  wherein the injecting an encapsulant material comprising transferring the encapsulant material at a pressure ranging from 1100 psi to 1400 psi.  
     
     
         3 . The method of  claim 2  wherein the injecting an encapsulant material is further performed in an environment with a dust count lower than or equal to about 30 k parts per million (PPM).  
     
     
         4 . The method of  claim 1  wherein the encapsulant material is configured to provide a transmission rate higher than or equal to 80% for a wavelengths longer than or equal to 350 nm.  
     
     
         5 . The method of  claim 1  wherein the encapsulant material comprises a plastic.  
     
     
         6 . The method of  claim 1  wherein the leadframe comprises an outer frame surrounding a plurality of die pads, the plurality of die pads including the first die pad and the second die pad.  
     
     
         7 . The method of  claim 6  wherein the plurality of die pads forms a two dimensional array.  
     
     
         8 . The method of  claim 6  wherein the forming a cavity comprises forming a plurality of side boundaries approximately on the outer frame.  
     
     
         9 . The method of  claim 6  wherein the outer frame comprises a plurality of elongated openings around the circumference of the outer frame.  
     
     
         10 . An apparatus for making an IC package with transparent encapsulant, the apparatus comprising: 
 a leadframe, the leadframe including an outer frame and a plurality of connecting bars, the plurality of connecting bars attached to the outer frame and defining a plurality of inner frames arranged in a matrix pattern within the outer frame, the plurality of inner frames including a plurality of die pads respectively;    a plurality of side boundaries located approximately on the outer frame;    wherein: 
 the plurality of side boundaries, the outer frame, and the plurality of inner frames form at least parts of a cavity;  
 the cavity is at least partially filled with a transparent encapsulant material; and  
 the encapsulant material is transparent for visible wavelengths.  
   
     
     
         11 . The apparatus of  claim 10  wherein the encapsulant material is configured to provide a transmission rate higher than or equal to 80% for a wavelengths longer than or equal to 350 nm.  
     
     
         12 . The apparatus of  claim 10  wherein the encapsulant material comprises a plastic.  
     
     
         13 . The apparatus of  claim 10  wherein the cavity is configured to receive an injection of the transparent encapsulant material performed at an encapsulant temperature ranging from 140° c to 160° c.  
     
     
         14 . The apparatus of  claim 13  wherein the cavity is further configured to receive the injection of the transparent encapsulant material at a pressure ranging from 1100 psi to 1400 psi.  
     
     
         15 . The apparatus of  claim 14  wherein the cavity is further configured to receive the injection of the transparent encapsulant material further performed in an environment with a dust count lower than or equal to about 30 k parts per million (PPM).  
     
     
         16 . The apparatus of  claim 10  wherein the outer frame comprises a plurality of elongated openings around the circumference of the outer frame.  
     
     
         17 . An IC package with transparent encapsulant, the package comprising: 
 a die pad including a pad bottom surface;    a die disposed on the die pad and including an integrated circuit;    a plurality of leads including a plurality of lead bottom surfaces;    a plurality of conductive wires connecting the die and the plurality of leads; and    an encapsulant material;    wherein: 
 the encapsulant material is transparent for visible wavelengths;  
 the pad bottom surface is exposed without being covered by the encapsulant material;  
 the plurality of lead bottom surfaces each are exposed without being covered by the encapsulant material.  
   
     
     
         18 . The IC package of  claim 17  wherein the encapsulant material is configured to provide a transmission rate higher than or equal to 80% for a wavelength longer than or equal to 350 nm.  
     
     
         19 . The IC package of  claim 18  wherein the encapsulant material comprises a plastic.  
     
     
         20 . The IC package of  claim 17  wherein: 
 the die is disposed on the die pad through a bonding layer;    the die pad includes a pad plating layer;    the plurality of leads include a plurality of lead plating layers respectively.