Carbon nanotube contact structures for use with semiconductor dies and other electronic devices
View Patent ↗A method of making carbon nanotube contact structures on an electronic device includes growing a plurality of carbon nanotube columns on a mandrel. Electrically-conductive adhesive is applied to ends of the columns distal from the mandrel, and the columns are transferred to the electronic device. An electrically-conductive material is deposited onto some or all of the columns. The mandrel can be reused to grow a second plurality of carbon nanotube columns.
1. A method of making carbon nanotube contact structures on a first electronic device, comprising:
growing a plurality of first carbon nanotube columns on a mandrel;
applying an electrically-conductive adhesive to ends of the first columns distal from the mandrel;
transferring the first columns to the first electronic device by bringing the ends of the first columns distal from the mandrel into contact with first terminals of the first electronic device;
separating the mandrel from the first columns to leave the first columns attached to the first terminals of the first electronic device by the electrically-conductive adhesive;
depositing an electrically-conductive material onto the first columns; and
reusing the mandrel to grow a second plurality of carbon nanotube columns on the mandrel,
wherein the applying an electrically-conductive adhesive comprises bringing a stamping tool into contact with the ends of the first columns distal from the mandrel to transfer the electrically-conductive adhesive from the stamping tool onto the ends of the first columns, wherein the electrically-conductive adhesive is applied to the stamping tool using a technique selected from the group consisting of coating and patterning.
2. The method of claim 1 , wherein the separating the mandrel from the first columns comprises physically separating the mandrel and the first electronic device.
3. The method of claim 1 , wherein the separating the mandrel from the first columns comprises applying a thermal shock to at least one of the first columns and the mandrel.
4. The method of claim 1 , wherein the depositing an electrically-conductive material is performed before the applying a conductive adhesive and the transferring the first columns to the first electronic device.
5. The method of claim 1 , wherein the depositing an electrically-conductive material is performed after the transferring the first columns to the first electronic device.
6. The method of claim 1 , wherein the depositing an electrically-conductive material comprises:
placing a first electrically-conductive material onto the first columns before the transferring the first columns to the first electronic device; and
placing a second electrically-conductive material onto the first columns after the transferring the columns to the first electronic device.
7. The method of claim 6 , wherein:
the first electrically-conductive material is selected from the group of ductile metals consisting of gold, silver, copper, aluminum, and combinations and alloys thereof; and
the second electrically-conductive material is selected form the group of rigid metals consisting of rhodium, nickel, palladium, cobalt, and combinations and alloys thereof.
8. The method of claim 1 , further comprising attaching tip structures onto ends of the first columns distal from the first electronic device.
9. The method of claim 1 further comprising attaching a semiconductor die to second terminals of the first electronic device, wherein the second terminals of the first electronic device are on an opposite side of the first electronic device from the first terminals, and ones of the first terminals are electrically connected to ones of the second terminals.
10. An electronic device comprising carbon nanotube contact structures formed in accordance with the method of claim 1 .
11. A method of making carbon nanotube contact structures on a first electronic device, comprising:
growing a plurality of first carbon nanotube columns on a mandrel;
applying an electrically-conductive adhesive to ends of the first columns distal from the mandrel;
transferring the first columns to the first electronic device by bringing the ends of the first columns distal from the mandrel into contact with first terminals of the first electronic device;
separating the mandrel from the first columns to leave the first columns attached to the first terminals of the first electronic device by the electrically-conductive adhesive;
depositing an electrically-conductive material onto the first columns; and reusing the mandrel to grow a second plurality of carbon nanotube columns on the mandrel, wherein the depositing an electrically-conductive material comprises:
positioning a stencil over the first electronic device such that the first columns extend through holes in the stencil and the first terminals of the device are exposed through the holes in the stencil; and
applying the electrically-conductive material through holes in the stencil to deposit the electrically-conductive material onto to the first columns and the first terminals.
12. The method of claim 11 , wherein the applying an electrically-conductive adhesive comprises bringing a stamping tool into contact with the ends of the first columns distal from the mandrel to transfer the electrically-conductive adhesive from the stamping tool onto the ends of the first columns, wherein the electrically-conductive adhesive is applied to the stamping tool using a technique selected from the group consisting of coating and patterning.