Forming a carbon nano-tube dispersion
Various embodiments disclose a molding compound comprising a resin, a filler, and a carbon nano-tube dispersion and methods of forming a package using the molding compound is disclosed. The carbon non-tube dispersion has a number of carbon nano-tubes with surfaces that are chemically modified by a functional group to chemically bridge the surfaces of the carbon nano-tubes and the resin, improving adhesion between the carbon nano-tubes and the resin and reducing agglomeration between various ones of the carbon nano-tubes. The carbon nano-tube dispersion achieves a low average agglomeration size in the molding compound thereby providing desirable electro-mechanical properties and laser marking compatibility. A shallow laser mark may be formed in a mold cap with a maximum depth of less than about 10 microns. Other apparatuses and methods are disclosed.
1. A method comprising:
forming a package having a portion formed from a molding compound comprising a resin, a filler, and carbon nano-tube dispersion, the carbon non-tube dispersion having a plurality of carbon nano-tubes with surfaces that are chemically modified by a functional group to chemically bridge the surfaces of the carbon nano-tubes and the resin to improve adhesion between the carbon nano-tubes and the resin and to reduce agglomeration between various ones of the plurality of carbon nano-tubes;
selecting the carbon nano-tube dispersion to comprise from about 0.001 percent by weight to about 0.05 percent by weight of the molding compound; and
irradiating a portion of the molding compound with a radiation source to produce a mark on a surface of the package.
2. The method of claim 1 , wherein the irradiating ablates the resin, the filler, and the carbon nano-tube dispersion.
3. The method of claim 1 , wherein the mark has a maximum depth of less than about 10 microns.
4. The method of claim 1 , further comprising curing the molding compound with microwave heating prior to forming the package.
5. The method of claim 1 , further comprising selecting portions of the molding compound to comprise:
the resin to be at about 10 to about 30 percent by weight;
and
the filler to be at about 60 to about 90 percent by weight.
6. The method of claim 1 , further comprising using a laser to produce the mark in the surface of the package.
7. A method of forming a package, the method comprising:
forming at least a portion of the package from a molding compound with a carbon nano-tube dispersion having a plurality of carbon nano-tubes;
selecting the carbon nano-tube dispersion to comprise from about 0.001 percent by weight to about 0.05 percent by weight of the molding compound; and
chemically modifying surfaces of the plurality of carbon nano-tubes with a functional group to reduce agglomeration between various ones of the plurality of carbon nano-tubes.
8. The method of claim 7 , further comprising forming the package from a resin and a filler.
9. The method of claim 8 , wherein the surfaces of the carbon nano-tubes that are chemically modified by the functional group chemically bridges the surfaces of the carbon nano-tubes and the resin thereby improving adhesion between the carbon nano-tubes and the resin.
10. The method of claim 8 , further comprising:
selecting the resin to comprise an epoxy; and
selecting the filler to comprise silica.
11. The method of claim 8 , further comprising:
selecting the filler to comprise between about 60 percent by weight to about 89 percent by weight of the molding compound; and
selecting the resin to comprise between about 10 percent by weight to about 30 percent by weight.
12. The method of claim 7 , wherein the chemical modification includes anchoring a silane coupling agent at one end to the surfaces of the plurality of carbon nano-tubes resulting in C—O—Si covalent bonding at the surfaces of the carbon nano-tubes, and bonding an opposing end of the silane coupling agent to the functional group.
13. A method comprising:
forming at least a portion of a package from a molding compound with a carbon nano-tube dispersion, the carbon non-tube dispersion having a plurality of carbon nano-tubes with surfaces that are chemically modified by a functional group for chemically bridging the surfaces of the carbon nano-tubes for reducing agglomeration between various ones of the plurality of carbon nano-tubes, the chemical modification including anchoring a silane coupling agent at one end to the surfaces of the plurality of carbon nano-tubes resulting in C—O—Si covalent bonding at the surfaces of the carbon nano-tubes, and bonding an opposing end of the silane coupling agent to the functional group; and
selecting the carbon nano-tube dispersion to comprise from about 0.001 percent by weight to about 0.05 percent by weight of the molding compound.
14. The method of claim 13 , wherein the chemical modification includes applying a silane coupling agent and 3-glycidoxypropyltrimethoxysilane (3-GPTMS).
15. The method of claim 13 , wherein the chemical modification further comprises:
surface treating the plurality of carbon nano-tubes with ultraviolet (UV) radiation; and
immersing the UV surface-treated plurality of carbon nano-tubes in silane.
16. The method of claim 15 , further comprising immersing the UV surface-treated plurality of carbon nano-tubes in silane for approximately six hours at about 60° C. to about 80° C.
17. A method of forming an electronic package, the method comprising:
bonding a semiconductor device to a substrate;
forming a molding compound over the semiconductor device and at least a portion of the substrate, the molding compound comprising a resin, a filler, and a carbon nano-tube dispersion, the carbon non-tube dispersion having a plurality of carbon nano-tubes with surfaces that are chemically modified by a functional group for chemically bridging the surfaces of the carbon nano-tubes and the resin thereby improving adhesion between the carbon nano-tubes and the resin and reducing agglomeration between various ones of the plurality of carbon nano-tubes;
selecting the carbon nano-tube dispersion to comprise from about 0.001 percent by weight to about 0.05 percent by weight of the molding compound; and
irradiating a portion of the molding compound with a radiation source to produce an identifying mark on a surface of the electronic package.
18. The method of claim 17 , wherein the molding compound is formed over the semiconductor device and at least a portion of the substrate by injection molding.
19. The method of claim 17 , further comprising selecting the carbon nano-tube dispersion to have an average agglomeration size of less than about one micron.
20. The method of claim 17 , further comprising selecting the functional group to be an epoxide group.
21. The method of claim 17 , wherein reducing the agglomeration between various ones of the plurality of carbon nano-tubes is for increasing an electrical resistance value in the molding compound as compared with an electrical resistance value of a plurality of agglomerated carbon nano-tubes.