Semiconductor device and method of forming shielding material containing conductive spheres
A semiconductor device has a substrate and an electrical component disposed over the substrate. An encapsulant is deposited over the electrical component and substrate. A shielding material, containing a plurality of spheres embedded in a matrix, is formed on the encapsulant. The shielding material 144 can be formed by spray coating, printing, liquid flow, or droplets. The spheres can have a curved or angled shape, e.g., circular, oval, or many flat or curved surfaces joining as a globe. The spheres each have a shell formed over a core. The shell can be a conductive material, while the core is an insulating material. Alternatively, the shell can be an insulating material, while the core is a conductive material. The shielding material scatters electromagnetic interference noise waves by reflection off the shell of the spheres. The shielding material can absorb electromagnetic interference noise waves into the core of the spheres.
1 . A semiconductor device, comprising: a substrate; an electrical component disposed over the substrate; an encapsulant deposited over the electrical component and substrate; an adhesive layer disposed in contact with the encapsulant; a first shielding layer formed in contact with a surface of the adhesive layer; and a second shielding material including a conductive ink and a plurality of spheres embedded in the conductive ink and deposited as droplets in contact with a surface of the first shielding layer encapsulant as droplets, wherein a first one of the plurality of spheres contacts a second one of the plurality of spheres to dissipate electro-magnetic interference and the first shielding layer remains absent the plurality of spheres.
2 . The semiconductor device of claim 1 , wherein the spheres each include:
a core; and
a shell formed over the core, wherein the shell of a first one of the plurality of spheres contacts the shell of a second one of the plurality of spheres to dissipate electro-magnetic interference.
3 . The semiconductor device of claim 2 , wherein the shell includes a conductive material and the core includes an insulating material.
4 . The semiconductor device of claim 2 , wherein the shell includes an insulating material and the core includes a conductive material.
5 . The semiconductor device of claim 2 , wherein the second shielding material scatters electromagnetic interference noise waves by reflection off the shell of the spheres.
6 . The semiconductor device of claim 2 , wherein the second shielding material absorbs electromagnetic interference noise waves into the core of the spheres.
7 . A semiconductor device, comprising:
an electrical component;
an encapsulant deposited over the electrical component;
a first shielding layer formed over the encapsulant; and
a second shielding material including a conductive ink and a plurality of spheres, each comprising a core and a shell formed over the core, embedded in the conductive ink and deposited in contact with a surface of the first shielding layer opposite the encapsulant, wherein the shell of a first one of the plurality of spheres contacts the shell of a second one of the plurality of spheres to dissipate electro-magnetic interference, while the first shielding layer remains absent the plurality of spheres.
8 . The semiconductor device of claim 7 wherein the shell includes a conductive material and the core includes an insulating material.
9 . The semiconductor device of claim 7 , wherein the shell includes an insulating material and the core includes a conductive material.
10 . The semiconductor device of claim 7 , wherein the second shielding material scatters electromagnetic interference noise waves by reflection off the shell of the spheres.
11 . The semiconductor device of claim 7 , wherein the second shielding material absorbs electromagnetic interference noise waves into the core of the spheres.
12 . The semiconductor device of claim 7 , further including a substrate, wherein the electrical component is disposed over the substrate.
13 . A method of making a semiconductor device, comprising:
providing a substrate;
disposing an electrical component over the substrate;
depositing an encapsulant over the electrical component and substrate;
forming a first shielding layer over the encapsulant; and
forming a second shielding material including a conductive ink and a plurality of conductive spheres embedded in the conductive ink and deposited as droplets in contact with a surface of the first shielding layer opposite the encapsulant, wherein a first one of the plurality of spheres contacts a second one of the plurality of spheres to dissipate electro-magnetic interference, while the first one of the spheres and the second one of the spheres are electrically isolated from the substrate and the first shielding layer remains absent the plurality of spheres.
14 . The method of claim 13 , wherein the spheres each include a shell formed over a core and the shell of a first one of the plurality of spheres contacts the shell of a second one of the plurality of spheres to dissipate electro-magnetic interference.
15 . The method of claim 14 , wherein the shell includes a conductive material and the core includes an insulating material.
16 . The method of claim 14 , wherein the shell includes an insulating material and the core includes a conductive material.
17 . The method of claim 14 , wherein the second shielding material scatters electromagnetic interference noise waves by reflection off the shell of the spheres.
18 . The method of claim 14 , wherein the second shielding material absorbs electromagnetic interference noise waves into the core of the spheres.
19 . A method of making a semiconductor device, comprising:
providing an electrical component;
depositing an encapsulant over the electrical component;
forming a first shielding layer over the encapsulant; and
forming a second shielding material including a conductive ink and a plurality of spheres embedded in the conductive ink and deposited in contact with a surface of the first shielding layer opposite the encapsulant, wherein a first one of the plurality of spheres contacts a second one of the plurality of spheres to dissipate electro-magnetic interference, while the first shielding layer remains absent the plurality of spheres.
20 . The method of claim 19 , wherein the spheres each include a shell formed over a core and the shell of a first one of the plurality of spheres contacts the shell of a second one of the plurality of spheres to dissipate electro-magnetic interference.
21 . The method of claim 20 , wherein the shell includes a conductive material and the core includes an insulating material.
22 . The method of claim 20 , wherein the shell includes an insulating material and the core includes a conductive material.
23 . The method of claim 20 , wherein the second shielding material scatters electromagnetic interference noise waves by reflection off the shell of the spheres.
24 . The method of claim 20 , wherein the second shielding material absorbs interference noise waves into the core of the conductive spheres.