US 12,266,629 B2
Ball bond impedance matching
Patrick E. Boyle, Dorchester, MA (US); James E. Benedict, Chelmsford, MA (US); Erika Klek, Wilmington, MA (US); and Mikhail Pevzner, Woburn, MA (US)
Assigned to Raytheon Company, Arlington, VA (US)
Filed by Raytheon Company, Arlington, VA (US)
Filed on Feb. 5, 2021, as Appl. No. 17/169,098.
Prior Publication US 2022/0254750 A1, Aug. 11, 2022
Int. Cl. H01L 23/00 (2006.01)
CPC H01L 24/48 (2013.01) [H01L 24/85 (2013.01); H01L 2224/48225 (2013.01); H01L 2224/48482 (2013.01); H01L 2224/85047 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method of forming an interconnection having a selected impedance, comprising:
providing a board having a first conductive layer, a first dielectric layer having a first hole in the first dielectric layer that exposes a portion of the first conductive layer, and a conductive trace on a top surface of the first dielectric layer;
selecting a number of balls in a ball stack to achieve the selected impedance, wherein the number of balls is at least two;
determining a radius of the balls to achieve desired capacitive and inductance characteristics of the selected impedance, wherein all of the balls have the same determined radius; and
using wire bonding equipment to melt wire to form the number of balls with the same determined radius on top of each other on the exposed portion of the first conductive layer in the first hole and bonded to each other with the top of the ball stack level with the top surface of the first dielectric layer and then to form a single wirebond interconnection from the top of the ball stack to the conductive trace.