Patent ID: 7772861

Claim:
A probe card for testing a wafer, comprising: a printed circuit board configured to transmit test signals; a fastened ring, arranged below said printed circuit board; and a plurality of needles passing through said fastened ring, each of the plurality of needles including one end for connecting with a circuit of said printed circuit board and including a tip portion at the other end for connecting to a pad of the wafer; wherein each needle comprises a bent portion between said fastened ring and said tip portion to absorb most or a majority of contact stress applied to the pad of the wafer, said fastened ring is made of a material comprising electrical conducting polymer, said plurality of needles comprises a metal core, an insulating cladding enclosing the metal core, and a metal shielding enclosing the insulating cladding, and the metal shielding electrically connects to said fastened ring, such that the grounding path and induction loop can be reduced.