Package-on-Package Structure Including a Thermal Isolation Material

Abstract

A semiconductor device includes a first package component and a second package component. The first package component has a first die formed on a first substrate. A second package component has a second die formed on a second substrate. A thermal isolation material is attached on the first die, wherein the thermal isolation material thermally insulates the second die from the first die, and the thermal isolation material has a thermal conductivity of from about 0.024 W/mK to about 0.2 W/mK. A first set of conductive elements couples the first package component to the second package component.

What is claimed is: 
     
         1 . A method comprising:
 disposing a thermal isolation material on a top surface of a die, wherein the die is comprised in a lower package component, and wherein at a time the thermal isolation material is disposed, outer edges of the thermal isolation material are aligned to corresponding edges of the die;   bonding an upper package component to the lower package component, wherein the thermal isolation material is between, and is in contact with, both of the die and the upper package component; and   after the upper package component is bonded to the lower package component, disposing a molding compound between the upper package component and the lower package component.   
     
     
         2 . The method of  claim 1 , wherein the thermal isolation material is a solid plate that continuously extends from a first edge of the die to an opposing second edge of the die. 
     
     
         3 . The method of  claim 1 , wherein the thermal isolation material comprises a porous film. 
     
     
         4 . The method of  claim 1 , wherein the thermal isolation material comprises an aerogel. 
     
     
         5 . The method of  claim 1 , wherein the thermal isolation material has a thermal conductivity value in a range between about 0.024 W/mK and about 0.2 W/mK. 
     
     
         6 . The method of  claim 1 , wherein the molding compound is dispensed in a flowable form, and the method further comprises curing to solidify the molding compound. 
     
     
         7 . The method of  claim 1 , wherein the thermal isolation material is in a form of a seal ring encircling a space therein, and wherein after the upper package component is bonded to the lower package component, an air gap or vacuum is enclosed by the seal ring, the upper package component, and the die. 
     
     
         8 . The method of  claim 7 , wherein the molding compound is in contact with the outer edges of the seal ring, with the outer edges of the seal ring being the outer edges of the thermal isolation material, and wherein inner edges of the seal ring are exposed to air or vacuum. 
     
     
         9 . The method of  claim 8 , wherein the seal ring encircles air therein. 
     
     
         10 . The method of  claim 7 , wherein the seal ring encircles a vacuumed space therein. 
     
     
         11 . A method comprising:
 forming a lower package comprising a device die;   bonding an upper package over the lower package; and   forming a filling region between the lower package and the upper package, wherein the filling region encircles a space that is between the upper package and the device die, and the space comprises an air space or a vacuumed space.   
     
     
         12 . The method of  claim 11 , wherein the filling region comprises:
 attaching a first material in a region directly over the device die; and   dispensing a second material vertically offset from the device die, wherein the second material is different from the first material.   
     
     
         13 . The method of  claim 12 , wherein the first material and the second material have interfaces that are vertically aligned to outer edges of the device die. 
     
     
         14 . The method of  claim 12 , wherein the first material and the second material are attached to the device die through different processes. 
     
     
         15 . A method comprising:
 forming a lower package component comprising bonding a die to a substrate;   forming a seal ring on a first top surface of the die;   bonding a upper package component to the lower package component, wherein a space is defined by the upper package component, the die, and the seal ring; and   dispensing an encapsulant between, and contacting both of, the upper package component and the lower package component, so that the space and the seal ring are encircled by the encapsulant, wherein the encapsulant and the seal ring form interfaces that extend from a bottom surface to a second top surface of the seal ring, and the interfaces are vertically aligned to corresponding edges of the die.   
     
     
         16 . The method of  claim 15  further comprising curing the encapsulant. 
     
     
         17 . The method of  claim 15 , wherein at a time after the encapsulant is dispensed, the space is an air gap. 
     
     
         18 . The method of  claim 15 , wherein at a time after the encapsulant is dispensed, the space is a vacuumed space. 
     
     
         19 . The method of  claim 15 , wherein the seal ring comprises inner edges that face the space, and the inner edges are vertical and straight edges. 
     
     
         20 . The method of  claim 15 , wherein the encapsulant is dispensed after the seal ring is formed.