Self-assembled nanometer conductive bumps and method for fabricating
A self-assembled nanometer conductive bump and a method for fabricating the bump. In the method, a multiplicity of carbon nanotubes that are coated at two ends with chemically functional groups is first provided. A substrate that is equipped with at least one bond pad on a surface is then positioned juxtaposed to the carbon nanotubes for forming a bond between the carbon nanotubes and the metal pads facilitated by a chemical affinity existed between the functional groups and the metal pad.
1. A self-assembly method for fabricating nanometer conductive bumps comprising the steps of:
providing a multiplicity of carbon nanotubes, each of said multiplicity of carbon nanotubes having two free ends;
attaching to said two free ends of said multiplicity of carbon nanotubes a plurality of functional groups;
providing a template having at least one metal pad on a surface;
attaching said multiplicity of carbon nanotubes to said at least one metal pad by an attraction force existed between said plurality of functional groups on said free end of said carbon nanotubes and said metal pad;
attaching a multiplicity of nanometer metal balls to the other free end of said multiplicity of carbon nanotubes forming a nanometer metal layer;
providing a substrate having at least a bond pad on a surface;
attaching said nanometer metal layer on said multiplicity of carbon nanotubes to said bond pad on the substrate; and
removing said template.
2. A self-assembly method for fabricating nanometer conductive bumps according to claim 1 further comprising the step of providing said functional groups from a group consisting of thiol groups, amide groups, imine groups and isocyanide groups.
3. A self-assembly method for fabricating nanometer conductive bumps according to claim 1 further comprising the step of fabricating said nanometer metal layer from a metal selected from the group consisting of gold, silver, copper, platinum and palladium.
4. A self-assembly method for fabricating nanometer conductive bumps according to claim 1 further comprising the step of removing said template by a wet etch method.
5. A self-assembly method for fabricating nanometer conductive bumps according to claim 1 further comprising the step of forming said nanometer metal layer with a metal that provides wetting characteristics during said attachment process between the nanometer metal layer and the bond pad on the substrate.
6. A self-assembly method for fabricating nanometer conductive bumps according to claim 1 further comprising the step of attaching said nanometer metal layer to said bond pad on the substrate by a solder layer.