Air bridge structures and methods of making and using air bridge structures
A probe card assembly, according to some embodiments of the invention, can comprise a tester interface configured to make electrical connections with a test controller, a plurality of electrically conductive probes disposed to contact terminals of an electronic device to be tested, and a plurality of electrically conductive data paths connecting the tester interface and the probes. At least one of the data paths can comprise an air bridge structure trace comprising an electrically conductive trace spaced away from an electrically conductive plate by a plurality of pylons.
1. A method of making an air bridge structure trace comprising:
providing a substrate comprising an electrically conductive plate;
depositing a plurality of layers of droplets onto the substrate, the droplets comprising:
droplets of a first material disposed to form a plurality of pylons on the plate, droplets of a second material disposed to fill spaces between the pylons, and
droplets of a third material disposed to form an electrically conductive outer seed layer;
electrodepositing a conductive material onto the seed layer; and
removing the droplets of the second material.
2. The method of claim 1 , wherein the seed layer is spaced away from the plate by ones of the pylons and generally parallel to the plate.
3. The method of claim 1 , wherein:
the droplets of the third material are disposed to form a plurality of seed layers each generally parallel to and spaced apart by ones of the pylons from the plate; and
the electrodepositing comprises electrodepositing the conductive material onto the seed layers.
4. The method of claim 1 , wherein:
the substrate further comprises an electrically conductive terminal; and
droplets of the third material are disposed to form a pylon on the terminal.
5. The method of claim 1 , wherein the first material comprises a dielectric material.
6. The method of claim 1 , wherein the removing comprises dissolving the droplets of the second material in a solvent that does not dissolve the first material.
7. The method of claim 6 , wherein the solvent comprises water.
8. The method of claim 1 , wherein the depositing comprises depositing the droplets through a print head.
9. The method of claim 8 , wherein the print head comprises an ink jet print head.
10. The method of claim 1 , wherein the conductive material forms a conductive trace spaced away from the plate by the pylons and generally parallel to the plate.
11. The method of claim 10 , wherein ones of the pylons disposed between the trace and the plate occupy less than twenty-five percent of a space between the trace and the plate.