Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
1998-07-30
2001-07-10
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S1540PB, C324S756010
Reexamination Certificate
active
06259260
ABSTRACT:
TECHNICAL FIELD
The present invention relates to wafer testing systems and, more particularly, to devices for coupling a test head and a probe card in a wafer testing system.
BACKGROUND INFORMATION
Wafer testing systems typically include a test head and a probe card. The probe card includes a pattern of contacts for electrically probing portions of an integrated circuit formed on a semiconductor wafer. The test head is configured to drive various contacts of the probe card to carry out particular test procedures within the integrated circuit. In the course of a test procedure, the test head receives output signals from the integrated circuit via the contacts of the probe card. The output signals are indicative of electrical characteristics of the integrated circuit under test. The probe card and test head are uniquely configured for a particular integrated circuit and, in some cases, a particular test procedure. Accordingly, the probe card and/or test head must be changed for different integrated circuits and test procedures.
The test head and probe card are electrically coupled to one another with a coupling apparatus often referred to as a “pogo” unit. The pogo unit engages the test head, or some intermediate coupling structure associated with the test head, and the probe card. The pogo unit includes an array of spring-loaded contacts referred to as pogo pins. The pogo pins are arranged to electrically couple contacts on the probe card to corresponding contacts on the test card. The spring force of the pogo pins helps maintain uniformity of electrical contact between the various contacts of the probe card and test head. When the test head and probe card are engaged with the pogo unit to exert pressure against the pogo pins, the pins respond with a spring force that enhances coupling pressure. The resilience of the pins generally ensures adequate coupling pressure despite planar deformation of the test head or probe card during a test procedure.
SUMMARY
The present invention is directed to an apparatus for coupling a test head and a probe card in a wafer testing system. The coupling apparatus incorporates a number of features that contribute to controlled impedance and reduced cross-talk. Consequently, the coupling apparatus is particularly advantageous for high-speed test applications. The coupling apparatus may include, for example, an array of discrete conductor conduits that contain individual conducting elements such as pogo pins. The conduits can be insulated, if desired, to reduce leakage. The conduits can be made from metal, and are terminated in dielectric interface plates for improved impedance matching. Divider elements can be provided to physically and electrically isolate adjacent rows of conductor conduits. Also, adjacent conducting elements can be connected to carry ground and signal potentials in an alternating manner such that signal carrying elements in a common row are separated from one another by ground carrying elements.
In one embodiment, the present invention provides an apparatus for coupling a test head and a probe card in a wafer testing system, the apparatus comprising a first plate having first sockets, a second plate having second sockets, conduits extending between the first plate and the second plate, each of the conduits having a first end mounted at one of the first contacts and a second end mounted at one of the second contacts, and electrical conducting members disposed within the conduits, each of the conducting members having a first end accessible via one of the first sockets and a second end accessible via one of the second sockets.
In another embodiment, the present invention provides an apparatus for coupling a test head coupling structure and a probe card coupling structure in a wafer testing system, the apparatus comprising a first dielectric plate having first sockets, a second dielectric plate having second sockets, metal conduits extending between the first plate and the second plate, each of the conduits having a first end mounted at one of the first sockets and a second end mounted at one of the second sockets, wherein the elongated conduits are generally arranged in rows, electrical shielding members disposed between adjacent rows of the conduits, thereby reducing electrical cross-talk, and electrical conducting members disposed within the conduits, each of the electrical conducting members having a first end accessible via one of the first sockets and a second end accessible via one of the second sockets.
In a further embodiment, the present invention provides an apparatus for coupling a test head coupling structure and a probe card coupling structure in a wafer testing system, the apparatus comprising a first dielectric plate having first sockets, a second dielectric plate having second sockets, conduits extending between the first plate and the second plate, each of the conduits having a first end mounted within one of the first sockets and a second end mounted within one of the second sockets, wherein the conduits are generally arranged in rows, electrical conducting members disposed within the conduits, each of the electrical conducting members having a first end accessible via one of the first sockets and a second end accessible via one of the second sockets, wherein alternating conducting members in each row of conduits carry a common ground signal and the conducting members between the alternating conducting members carry data signals, thereby reducing electrical cross-talk, and electrical shielding members disposed between adjacent rows of the conduits, thereby reducing electrical cross-talk.
In an added embodiment, the present invention provides a wafer testing apparatus comprising a test head coupling structure having first pins, a probe card coupling structure having second pins, a first plate having first sockets receiving the first pins, a second plate having second sockets receiving the second pins, conduits extending between the first plate and the second plate, each of the conduits having a first end mounted at one of the first contacts and a second end mounted at one of the second contacts, electrical conducting members disposed within the conduits, each of the conducting members having a first end accessible by one of the first pins via one of the first sockets and a second end accessible by one of the second pins via one of the second sockets, some of the first pins thereby being electrically coupled to at least some of the second pins.
Other advantages, features, and embodiments of the present invention will become apparent from the following detailed description and claims.
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Sargent, IV Thornton W.
Smith Douglas W.
InTest IP Corporation
Metjahic Safet
Nguyen Jimmy
Ratner & Prestia
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