Electrically Conductive Pins For Microcircuit Tester

Abstract

The terminals of a device under test (DUT) are temporarily electrically connected to corresponding contact pads on a load board by a series of electrically conductive pin pairs. The pin pairs are held in place by an interposer membrane with a top facing the device under test, a bottom facing the load board, and a vertically resilient, non-conductive member between the top and bottom contact plates. Each pin pair includes a top and bottom pin, which extend beyond the top and bottom contact plates, respectively, toward the device under test and the load board, respectively. The bottom pins has a lower contact surface which includes an arcuate portion or ridge which increases contact pressure and ablates oxides by the rocking action of ridge when the DUT in inserted.

1 . In a contactor to be interposed between a contact load board and a device under test, the contactor including a plurality of having a plurality of contact pads ( 4 ), each contact pad ( 4 ) being laterally arranged to correspond to exactly one terminal ( 2 ), comprising:
 a longitudinally compressible membrane ( 10 ) for forming a plurality of temporary mechanical and electrical connections between a device under test ( 1 )   a longitudinally resilient, electrically insulating interposer ( 50 ) between the load board and device under test;   a plurality of longitudinally slideable, electrically conductive pin pairs ( 20 ,  30 ) extending through longitudinal holes in the interposer each pin pair in the plurality being laterally arranged to correspond to one terminal ( 2 ) on the device under test ( 1 );   the plurality of pin pairs including a top and bottom contact, the top contact having a top engagement surface which engages electrical connections to a device under test, said top engagement; the bottom contact for engaging a contact on the load board;   the improvement comprising;
 said bottom contact which engages said load board includes a bottom surface, said bottom surface being arcuate. 
   
     
     
         2 . The contactor of  claim 1  wherein said bottom surface includes a cylindrical ridge. 
     
     
         3 . The contactor of  claim 1  wherein said bottom surface includes a ridge extending downwardly toward said load board. 
     
     
         4 . The contactor of  claim 1  wherein said bottom surface includes a rocking member for contracting the load board. 
     
     
         5 . The contactor of  claim 1  wherein said bottom surface includes a partial cylinder with its curved portion for contacting a load board. 
     
     
         6 . The contactor of  claim 1  wherein said bottom surface includes a sharp ridge. 
     
     
         7 . The contactor of  claim 1  wherein said bottom surface includes a plurality of sharp ridges. 
     
     
         8 . The contactor of  claim 1  wherein said bottom surface includes a plurality of parallel arcuate shapes. 
     
     
         9 . The contactor of  claim 1  wherein said bottom surface is non-planar. 
     
     
         10 . A method of lowering the resistance between a terminal on an integrated circuit and the load board having
 an electrically conductive pin having a bottom surface engagable with the load board, the method comprising;   forming the bottom surface to include an arcuate ridge along the surface, whereby engagement of the ridge with the terminal will focus contact pressure over a small surface area and may further cause ablation of oxides on the terminal.   
     
     
         11 . The method of  claim 10  wherein the step of forming the bottom surface includes forming a cylindrical foot thereon. 
     
     
         12 . The method of  claim 10  wherein the step of forming the bottom surface includes forming a foot with a peaked ridge thereon.