a plug - in zero insertion force type socket for making temporary electrical connection between the leads on a semiconductor device and testing circuitry where each connection between the high density array of semiconductor device leads and testing circuitry is shielded from external radiation to eliminate cross talk and capacitance coupling . transit time effects on the shielded electrical connections are minimized by providing short electrical connections which include a high density flared array of coaxial leads connecting a multi - planar arrangement of testing circuitry to the socket .