Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
2001-12-27
2003-12-23
Cuneo, Kamand (Department: 2829)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S760020, C324S754090
Reexamination Certificate
active
06667631
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the field of probe cards used for testing a semiconductor device-under-test, such as an integrated circuit (IC) device, including a semiconductor wafer, and more particularly, this invention relates to a probe card that can withstand high temperatures when testing a semiconductor device-under-test.
BACKGROUND OF THE INVENTION
Probe cards are used in the semiconductor manufacturing process when a semiconductor device-under-test, such as a semiconductor wafer, is tested in an Electrical Wafer Sort (EWS) test, a Final Test (FT), or other similar testing procedure. Throughout the following description, the term “Device-Under-Test” (DUT) is a common term and refers equally to the probe testing of dice during the Electrical-Wafer-Sort (EWS) or wafer probe or to the testing of an assembled or packaged dice or device during the Final Test (FT).
Many different probe cards are commercially available for use with different fixtures and testing systems. An example is disclosed in commonly assigned U.S. Pat. No. 5,187,431 to Libretti, issued Feb. 16, 1993, the disclosure which is hereby incorporated by reference in its entirety. Other probe cards and testing devices as representative examples are disclosed in U.S. Pat. Nos. 6,277,218; 4,906,920; and 6,181,145.
Greater numbers of CMOS and BiCMOS semiconductor devices are now providing customers a wide range of device usages. The increased use of these technologies include their use in the telecommunication and automotive industries under extreme conditions at very high and very low temperatures. Therefore, the Electrical Wafer Sort and Final Tests must guarantee device functionality at these extreme temperature ranges.
Many probe cards currently in use provide stacked printed circuit boards that form a probe interface board, having a lower testing face that carries a probe needle module (“spider”), having a large number of probe needles that electrically connect to electrical contacts (bond pads) of a semiconductor device-under-test (die). The probe interface board has various testing components mounted on the board, such as on its top surface. Typically, these probe cards have good performance in a standard EWS testing temperature range from about 25° C. to about 70-80° C. Modern car engine controls and microcontrollers, on the other hand, as commonly used in telecommunication and some automotive applications, have operating temperature ranges that occur above 130° C. Thus, a normal prior art probe card will be subject to overheat and thermal expansions and contractions. As a result, this probe card would be subject to printed circuit board misplanarity, probe tip misplanarity, probe needle misplanarity, defects in the printed circuit board layer stack, and defects in mounted components on the printed circuit board forming the probe interface board.
Some of these defects, such as probe tip and needle misplanarity, are recoverable, even though recovery may take a large amount of time and human resources to correct the resulting problems. Some of the defects, however, are unrecoverable defects, including the permanent deformation of the printed circuit board and broken or shorted printed circuit board internal layers.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a high temperature probe-card that withstands high temperatures and temperature variations for testing of a semiconductor device-under-test, which overcomes the drawbacks as identified above.
The present invention is advantageous and provides a probe card for testing a semiconductor dice-under-test on semiconductor wafers, which allows use of the probe card at extremely high wafer probe temperatures and maintains the wafer probe process on the same levels as for wafer probing at temperatures under 70-80° C. The present invention allows stable and reliable wafer probing at very high wafer probe temperatures, up to about 180° C. to about 200° C. by eliminating and minimizing heat impacts such as thermal deformations.
The present invention advantageously allows a gain in tester output capacity, tester time, and tester resources. The increased temperatures at which the probe card is usable also provides reliable wafer probing at around 180° C. to about 200° C., which is important for various semiconductor devices in automotive, telecommunication and military applications. The probe card of the present invention also provides increased planarity stability for probe needles at higher probe temperatures and increased co-planarity of the probe tips. The present invention provides extension of the probe capabilities of EWS testing departments with minimal investment.
The probe card of the present invention allows testing of semiconductor dice-under-test. A plurality of printed circuit boards are stacked together to form a probe interface board having a top surface and lower testing face. A heat sink is mounted on the probe interface board at the top surface and extends to the lower testing face. A needle supporting module is carried by the heat sink at the lower testing face and includes a plurality of probe needles for electrically connecting to electrical contacts of a semiconductor device-under-test.
In one aspect of the invention, the needle supporting module is formed from a thermally conducting ceramic material. The lower testing face on the probe interface board includes electrical contacts for interfacing with testing components carried by the probe interface board and an electrical connector extending from the electrical contacts to the needle supporting module for electrically connecting the probe needle to testing components carried by the probe interface board.
In yet another aspect of the present invention, the probe interface board is formed to have a central opening and edge defined by the central opening. The heat sink extends along the edge and around onto the lower testing face. The central opening can be substantially rectangularly configured. The heat sink also includes an outer portion, a central portion engaging the edge defined by the central portion, and at least one radial arm extending from the outer portion to the central portion. A mount is formed within the heat sink on the portion that extends around the lower testing face under which the needle supporting module mounts. The heat sink is formed of a metallic material and can be formed by one of copper or steel.
In yet another aspect of the present invention, at least one copper layer is positioned within the probe interface board and engages the heat sink to accumulate heat within the probe interface board and transfer heat to the heat sink. The upper layer also provides internal support to the probe interface board. The copper layer can be formed as two, spaced copper layers positioned within the probe interface board between various printed circuit board layers forming the probe interface board. Each copper layer is electrically insulated as having no electrical interconnection to any electrical components of a printed circuit board forming the probe interface board. A copper layer is preferably formed to have at least twice the thickness as a printed circuit board forming the probe interface board.
In yet another aspect of the present invention, a probe card is provided for testing a semiconductor device-under-test and includes a plurality of printed circuit boards stacked together to form a probe interface board having a top surface, a central opening defining an edge, and a lower testing face. A heat sink is mounted on the probe interface at the top surface and extends along the edge defined by the central opening to the lower testing face. At least one copper layer is positioned within the probe interface board and engages the heat sink to accumulate heat within the probe interface board and transfer heat to the heat sink and provide internal support to the probe interface board. A needle supporting module is carried by the heat sink and has a plurality of probe needles for electrically connecting to electrical conta
Cuneo Kamand
Kobert Russell M.
Regan Christopher F.
STMicroelectronics Inc.
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