Wafer probe station having full guarding

A method for guarding a probe station comprising:

• (a) providing a probe-holding assembly for holding an electrical probe;
• (b) providing a chuck assembly having respective first and second chuck assembly elements electrically insulated from each other, said first chuck assembly element having an upper surface for horizontally supporting a test device for probing by said electrical probe, a lower surface opposite said upper surface and a peripheral surface extending between said upper and lower surfaces;
• (c) shielding said chuck assembly against electromagnetic radiation via an electrically conductive outer enclosure enclosing said chuck assembly;
• (d) providing on said second chuck assembly element respective upper and lower components each of conductive material and each in spaced relationship to said first chuck assembly element, said upper component including a surface portion extending opposite said upper surface, said lower component including a surface portion extending opposite said lower surface;
• (e) providing a connector mechanism;
• and
• (f) electrically guarding said first chuck assembly element by means of said second chuck assembly element including the steps of establishing, via said connector mechanism, a first potential difference between said first chuck assembly element and said outer enclosure and a second potential difference substantially equal to said first potential difference between said second chuck assembly element and said outer enclosure.

A probe station comprising:

• (a) a probe-holding assembly for holding an electrical probe;
• (b) a chuck assembly having an upper surface for horizontally supporting a test device for probing by said electrical probe;
• (c) a connector mechanism including respective first and second conductive line elements in exterior arrangement to each other for electrical connection with one of said electrical probe and said chuck assembly;
• (d) an electrically conductive outer enclosure enclosing said first and second conductive line elements;
• (e) an electrically conductive inner enclosure surrounding said first conductive line element in interposed relationship between said first conductive line element and said outer enclosure, said second conductive line element being electrically connected to said inner enclosure;
• and
• (f) said connector mechanism enabling a first nonzero potential difference to be established between said first conductive line element and said outer enclosure and a second nonzero potential difference substantially equal to said first nonzero potential difference to be established between said inner enclosure and said outer enclosure.