Fixing apparatus for a probe card

A fixing apparatus for fixing a probe card to a holder includes a screw fixed to the holder and binding the probe card onto the holder in a vertical direction, a first bearing member intervening between a head of the screw and the probe card and allowing expansion and contraction of the probe card with respect to the screw in a horizontal direction, and a second bearing member intervening between the probe card and the holder and allowing expansion and contraction of the probe card with respect to the holder in the horizontal direction.

TECHNICAL FIELD

The present invention relates to a fixing apparatus for fixing to a holder a probe card to be used in a test of various types of electronic device (hereinafter referred also to as representatively “IC device”) such as an integrated circuit device formed on a semiconductor wafer.

BACKGROUND ART

In a production process of electronic devices, such as IC devices, there has been used an electronic device testing apparatus for testing performances and functional capabilities of IC devices in a situation where IC devices are embedded on a semiconductor wafer or packaged.

As the apparatus for testing electrical characteristics of an IC device embedded on a semiconductor wafer W under test, as shown inFIG. 6, one which pushes a wafer W by a prober90against a probe card50and tests the electrical characteristics of the IC device by a tester (not shown) via the probe card50and the test head10in the state bringing probe needles51mounted on the probe card50into electrical contact with electrodes of the IC device.

A heat source94is provided in the prober90. Due to heating and cooling the semiconductor wafer W by the heater, a test of the IC device is executed under the condition where a predetermined heat stress is applied on the semiconductor wafer W.

Meanwhile, the probe card50is tightly fixed to a holder70by using screws55or the like at a peripheral portion thereof. Accordingly, when there occurs a thermal expansion or a thermal contraction in the probe card50in accordance with a temperature change of the semiconductor wafer W, the probe card50deforms in the vertical direction, as shown inFIGS. 7A to 7C, thereby front ends of the probe pins51fluctuate in their heights. As a result, contact pressures of the probe needles51pressed to the electrodes on the semiconductor wafer W under test fluctuate, and it may be difficult to perform a test in high accuracy.

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

The object of the present invention is to provide a fixing apparatus for a probe card which can suppress the fluctuation in heights of the front ends of the probe needles.

Means for Solving the Problems

In order to achieve the object, in accordance with the present invention, there is provided a fixing apparatus for fixing to a holder a probe card to be used in a test of a device under test formed on a semiconductor wafer, wherein the probe card is provided stretchably with respect to the holder in a direction substantially parallel to a main surface of the probe card, and the probe card is bound onto the holder in a direction substantially perpendicular to the main surface of the probe card (refer to claim1).

Although not limited in the present invention, it is preferable that the fixing apparatus comprises: a binding means for binding the probe card onto the holder in the direction substantially perpendicular to the main surface of the probe card; and an allowing means for allowing expansion and contraction of the probe card with respect to the holder in the direction substantially parallel to the main surface of the probe card (refer to claim2).

Although not limited in the present invention, it is preferable that the binding means is fixed to the holder, and the allowing means includes: a first bearing member intervening between the binding means and the probe card and allowing expansion and contraction of the probe card with respect to the binding means in the parallel direction; and a second bearing member intervening between the probe card and the holder and allowing expansion and contraction of the probe card with respect to the holder in the parallel direction (refer to claim3).

Although not limited in the present invention, it is preferable that the binding means includes a screw member being fixed to the holder via a through-hole formed on a stiffener of the probe card (refer to claim4).

Although not limited in the present invention, it is preferable that the binding means is fixed to the probe card, and the allowing means includes: a first bearing member intervening between the binding means and the holder and allowing a small movement of the binding means with respect to the holder in the parallel direction; and a second bearing member intervening between the holder and the probe card and allowing expansion and contraction of the probe card with respect to the holder in the parallel direction (refer to claim5).

Although not limited in the present invention, it is preferable that the binding means includes a screw member being fixed to a stiffener of the probe card via passing through a through-hole formed on the holder (refer to claim6).

Although not limited in the present invention, it is preferable that the fixing apparatus comprises: a guiding member provided on one of the probe card or the holder along the direction substantially parallel to the main surface of the probe card; and a sliding member provided on another of the holder or the probe card, engaged with the guiding member in the direction perpendicular to the main surface of the probe card and being able to slide on the guiding member (refer to claim7).

In order to achieve the object, in accordance with the present invention, there is provided a testing apparatus for an electronic device, comprising: a testing apparatus main frame for testing a device under test formed on a semiconductor wafer; a probe card for establishing an electrical connection between the device under test and the testing apparatus main frame; a prober for pressing the probe card onto the semiconductor wafer; and a holder for fixing the probe card to the prober. The probe card is fixed to the holder by using the above-described fixing apparatuses (refer to claim8).

Advantageous Effect of the Invention

According to the present invention, the fixing apparatus allows the deformation of the probe card caused by thermal expansion or thermal contraction thereof to escape in the horizontal direction. Therefore, the deformation of the probe card in the vertical direction is reduced, and the front ends of the probe needles become less variation in their heights.

DESCRIPTION OF REFERENCE NUMERALS

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1is a schematic sectional view illustrating a structure of an electronic device testing apparatus according to a first embodiment of the present invention,FIG. 2is a schematic sectional view illustrating a fixing apparatus according to the first embodiment of the present invention, andFIG. 3is a sectional view illustrating the fixing apparatus according to the first embodiment of the present invention in case that a probe card thermally expands.

An electronic device testing apparatus1according to the first embodiment of the present invention is an apparatus for testing electrical characteristics of an IC device embedded on a semiconductor wafer W under test. As shown inFIG. 1, the electronic device testing apparatus1has a test head10electrically connected through a cable with a tester (not shown) for testing the IC device, a probe card50for establishing an electrical connection between the IC device on the semiconductor wafer W under test and the test head10, and a prober90for pressing the semiconductor wafer W under test onto the probe card50.

The probe card50is, as shown inFIG. 1, electrically connected with the test head10through a Hifix11. The probe card50is configured to have a large number of probe needles51to be electrically contacted with electrodes of the IC device embedded on the semiconductor wafer W under test, a printed circuit board52on which the probe needles51are mounted, a plurality of connectors53for electrically connecting the probe card50to connectors12provided on the Hifix11side, and a stiffener54for reinforcing the probe card50.

As shown in the figure, the probe needles51are mounted on a approximately center area of one main surface of the printed circuit board52, and arranged so as to correspond to the electrodes of the IC device embedded on the semiconductor wafer W under test. In contrast, the connectors53and the stiffener54are provided on the other main surface of the printed circuit board52, and each probe needle51is electrically connected to the connector53via a wiring pattern formed in the printed circuit board52.

The probe card50is held by a ring shaped holder70in a posture such that the probe pins51faces downward through a center opening71of the holder70. The probe card50is fixed to the holder70by means of fixing apparatuses60A at several peripheral positions thereof.

The screw61is fixed at a thread portion61bto a fix hole72formed on the holder70via a through-hole54bformed in the stiffener54of the probe card50. Because A head61aof the screw61has an outer diameter which is larger than the inner diameter of the through-hole54bof the stiffener54, by fixing the screw61to the holder70, the screw61binds the probe card50with respect to the holder70in the vertical direction. It is to be noted that the through-hole54bof the stiffener54is formed so as to have a diameter slightly larger than the diameter of the thread portion61bof the screw61in order to allow the probe card50to have a stretchability with respect to the screw61in the horizontal direction. In addition, the head61aof the screw61is positioned in a recessed area54aof the stiffener54.

The first bearing member62is configured to have a plastic frame and a plurality of balls supported by the plastic frame such that the plurality of balls are rotatably arranged in a circular pattern. The first bearing member62has an inner opening in which the thread portion61bof the screw61is inserted, and intervenes between the head61aof the screw61and the stiffener54. The first bearing member62allows the probe card50to have a stretchability with respect to the screw61in the horizontal direction.

Similarly, the second bearing member63is configured to have a plastic frame and a plurality of balls supported by the plastic frame such that the plurality of balls are rotatably arranged in a circular pattern. The second bearing member63has an inner opening in which the thread portion61bof the screw61is inserted, and is inserted between the stiffener54and the holder70. The second bearing member63allows the probe card50to have a stretchability with respect to the holder70in the horizontal direction.

Referring again toFIG. 1, the holder70holding the probe card50as described above is held by a ring-shaped adapter80, and the adapter80is further held by an opening92formed at a top plate91of the prober90. The adapter80is used for adapting to the opening92of the prober90probe cards50having different sizes in accordance with products category of the semiconductor wafer W under test and the shape of the test head10, or the like. The probe card50side and the Hifix11side are mechanically connected to each other by engaging a hook13provided at the downside of the Hifix11with a hook81provided at the adapter80.

The Hifix11is attached to the bottom of the test head10. The Hifix11is provided with the connector12at the lower surface thereof. One end of the connector12is electrically connected with a coaxial cable which is electrically with the test head10. Therefore, by connecting the connector12of the test head10side with the connector53provided with the probe card50, the test head10is electrically connected with the probe card50. For example, ZIF (Zero Insertion Force) connectors or the like may be used as the connectors12and53.

The prober90has a carrier arm93for moving the semiconductor wafer W under test held by a suction stage in X-Y-Z directions and for rotating θ the wafer W around the Z-axis. In addition, a heater or the like as a thermal source94is embedded in the suction stage of the carrier arm93, thereby enabling to heat the semiconductor wafer W held by suction. Alternatively, in the case of cooling the semiconductor wafer W under test during the testing of the IC device, a refrigerant may be circulated in the suction stage of the carrier arm93.

During the test, the carrier arm93makes the semiconductor wafer W to face to the probe card50approaching into the prober90through the opening92, and presses the semiconductor wafer W to the probe card50. In this situation, the tester inputs a testing signal into the IC device embedded in the wafer W and receives a signal output from the IC device, thereby to execute the test of the IC device.

In this period, since the thermal source94heats the wafer W under test, the wafer W may thermally expand. In the present embodiment, when the semiconductor wafer W under test thermally expands, as shown inFIG. 3, balls of the bearing members62and63rotates, and the first bearing member62allows the probe card50to expand in the horizontal direction with respect to the screw61and the second bearing member63allows the probe card50to expand in the horizontal direction with respect to the holder70so as to escape the thermal expansion of the probe card50in the horizontal direction. As a result, the deformation of the probe card50in the vertical direction is reduced, and the front ends of the probe needles51become less variation in their heights.

It is to be noted that the fixing apparatus according to the present invention is not limited to the structure as described above.

FIG. 4is a schematic sectional view illustrating a fixing apparatus according to a second embodiment of the present invention. A fixing apparatus60B according to the second embodiment of the present invention includes, as shown inFIG. 4, similarly to the first embodiment, a screw64and two bearing members65and66. The different points from the first embodiment are, however, that the screw64is fixed to the stiffener54through a through-hole formed in the holder70, that the first bearing member65intervenes a head of the screw64and the holder70, and that the second bearing member66intervenes the holder70and the stiffener54.

In the present embodiment, when the semiconductor wafer W under test thermally expands, balls of the bearing members65and66rotates, and the first bearing member65allows a small movement of the screw64in the horizontal direction with respect to the holder70and the second bearing member66allows the probe card50to expand in the horizontal direction with respect to the holder70so as to escape the thermal expansion of the probe card50in the horizontal direction. As a result, the deformation of the probe card50in the vertical direction is reduced, and the front ends of the probe needles51become less variation in their heights.

FIG. 5is a schematic sectional view illustrating a fixing apparatus according to a third embodiment of the present invention. A fixing apparatus60C according to the third embodiment of the present invention has a linear guide67, as shown inFIG. 5. The linear guide67includes a guide rail67aprovided on an upper surface of the holder70along radial direction, and a sliding member67bfixed to a lower surface of the probe card50by means of a screw and being able to slide on the guide rail67a. The sliding member67bis engaged with a groove formed on a side surface of the guide rail67ain order to avoid removing of the sliding member67bfrom the guide rail67ain the vertical direction.

In the present embodiment, when the semiconductor wafer W under test thermally expands, the sliding member67bslides on the guide rail67aso as to escape the thermal expansion of the probe card50in the horizontal direction. As a result, the deformation of the probe card50in the vertical direction is reduced, and the front ends of the probe pins51become less variation in their heights. Alternatively, the guide rail67amay be fixed to the lower surface of the stiffener54and the sliding member67bmay be fixed to the upper surface of the holder70

Note that, the above explained embodiment was described for facilitating understanding of the present invention and was not described for limiting the present invention. Therefore, the elements disclosed in the above embodiment include all design changes and equivalents falling under the technical scope of the present invention.

For example, although it is described the case that the probe card50thermally expands in the above first to third embodiments, when the probe card50thermally contracts by cooling, the fixing apparatuses60A to60C allow the deformation of the probe card50to escape in the horizontal direction.