Hi Richard, 
 
Thanks for the link. It appears that Motorola's focus and claims were  around 
a polymer column.  
 
Tessera disclosed and patented a polymer ball concept in the same  general 
time frame. 
 
The operative sentence is "each conductive element 26 incorporates a  
flexible body 28 covered by a thin, flexible conductive shell 30"  
 
The first claim reads

1. A method of making a semiconductor chip assembly comprising the  steps of: 

(a) providing a plurality of deformable electrically  conductive elements, 
each including a thin, flexible metallic shell extending  over at least a 
portion of the surface of the conductive element, and mounting  said conductive 
elements to contacts on a chip so that the metallic shells are  exposed; then 

(b) connecting the chip to a substrate by metallurgically  bonding the 
conductive elements to contact pads on the substrate. 

I suspect that there are a number of other concepts out there as well. 
 
Very best, 
Joe
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