Wafer probe station having a skirting component

• US 7,589,518 B2
• Filed: 02/11/2005
• Issued: 09/15/2009
• Est. Priority Date: 06/11/1992
• Status: Expired due to Fees

• Current Assignee: Cascade Microtech Incorporated (FormFactor Incorporated)
• Original Assignee: Cascade Microtech Incorporated (FormFactor Incorporated)
• Inventors: Smith, Kenneth R., Warner, Richard H., Schwindt, Randy J., Harwood, Warren K., Tervo, Paul A.
• Primary Examiner(s): KARLSEN, ERNEST F
• Application Number:
  US11/056,647
• Publication Number:
  US 20050184744A1
• Time in Patent Office: 1,677 Days
• Field of Search: None
• US Class Current: 324/757.03
• CPC Class Codes: A46D 1/00 Bristles; Selection of materials for bristles making artificial bristles D01D, D01F
• CPC Class Codes: G01R 1/0416 Connectors, terminals G01R1/0425 and G01R1/0433 take precedence; with measurement function for battery poles G01R31/364
• CPC Class Codes: G01R 1/06705 Apparatus for holding or moving single probes for moving multiple probe heads or ICs under test G01R31/2886
• CPC Class Codes: G01R 1/06794 Devices for sensing when probes are in contact, or in position to contact, with measured object
• CPC Class Codes: G01R 1/07392 manipulating each probe element or tip individually
• CPC Class Codes: G01R 1/18 Screening arrangements against electric or magnetic fields, e.g. against earth's field
• CPC Class Codes: G01R 31/2886 Features relating to contacting the IC under test, e.g. probe heads; chucks G01R31/2865 takes precedence, test connections, e.g. test sockets, or probes per se, G01R1/04 or G01R1/06
• CPC Class Codes: G01R 31/2887 involving moving the probe head or the IC under test; docking stations moving single probes G01R1/06705; moving individual probes in multiple probes G01R1/07392
• CPC Class Codes: H01L 21/68785 characterised by the mechanical construction of the susceptor, stage or support

Abstract

A probe station includes a fully guarded chuck assembly and connector mechanism for increasing sensitivity to low-level currents while reducing settling times. The chuck assembly includes a wafer-supporting first chuck element surrounded by a second chuck element having a lower component, skirting component and upper component each with a surface portion extending opposite the first element for guarding thereof. The connector mechanism is so connected to the second chuck element as to enable, during low-level current measurements, the potential on each component to follow that on the first chuck element as measured relative to an outer shielding enclosure surrounding each element. Leakage current from the first chuck element is thus reduced to virtually zero, hence enabling increased current sensitivity, and the reduced capacitance thus provided by the second chuck element decreases charging periods, hence reducing settling times. With similar operation and effect, where any signal line element of the connector mechanism is arranged exterior of its corresponding guard line element, such as adjacent the chuck assembly or on the probe-holding assembly, a guard enclosure is provided to surround and fully guard such signal line element in interposed relationship between that element and the outer shielding enclosure.

Claims

1. A probe station having a chuck for supporting a semiconductor under test comprising:

(a) a screw with a screw head and a shaft supported by said chuck;

(b) a conductive member laterally surrounding and spaced apart from said chuck, wherein said shaft supports said conductive member and said screw head is exterior to said conductive member;

(c) a spacer surrounding said shaft and positioned between said conductive member and said chuck, wherein said spacer and said conductive member are at the same potential; and

(d) a probe for testing a semiconductor resting on said chuck.

2. The probe station of claim 1 wherein said conductive member comprises a skirt extending vertically above said chuck.

3. The probe station of claim 1 wherein said conductive member is a sheet-like shield.

4. The probe station of claim 1 wherein said screw passes through an oversized aperture in said chuck thereby preventing contact between said shaft and said chuck.

5. The probe station of claim 1 wherein said spacer is constructed of a material having low dielectric constant.