Probe card

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2004-012077, filed Jan. 20, 2004, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a probe card used to test the electrical characteristics of an object to be tested such as a semiconductor element (to be described as a “device” hereinafter) formed on a wafer. More particularly, the present invention relates to a probe card capable of performing highly reliable testing even after it has become thermally deformed.

2. Description of the Related Art

A probe card is used in, e.g., a prober shown in FIG. 4. As shown in FIG. 4, the prober has a loader chamber 1 and a prober chamber 2. A wafer W is transported from the loader chamber 1. In the prober chamber 2, the electrical characteristics of a device or the like formed on the wafer W transported from the loader chamber 1 are tested. The wafer W is prealigned in the loader chamber 1, and transported into the prober chamber 2.

As shown in FIG. 4, the prober chamber 2 can include a main table 3, X-Y table 4, probe card 5, and alignment mechanism 6. The prealigned wafer W is placed on the main table 3. The main table 3 can adjust the temperature of the wafer W. The X-Y table 4 moves the main table 3 in the X and Y directions. The probe card 5 is arranged above the main table 3. The alignment mechanism 6 accurately aligns a plurality of probes 5A of the probe card 5 and the plurality of electrodes of the wafer W on the main table 3. As shown in, e.g., FIG. 5A, the probe card 5 can have the plurality of probes 5A, a printed wiring board 5B, reinforcing member 5D, and connecting members 5C. The probes 5A are connected to the printed wiring board 5B. The reinforcing member 5D is made of a metal such as stainless steel. The connecting members 5C connect the printed wiring board 5B and reinforcing member 5D to each other. The main table 3 incorporates an elevating mechanism. The elevating mechanism vertically moves the wafer W, to bring the probes 5A and electrodes on the wafer W into electrical contact with each other and electrically disconnect them from each other.

As shown in FIG. 4, a test head T connected to a tester is turnably disposed on a head plate 7 of the prober chamber 2. The test head T and probe card 5 are electrically connected to each other through a performance board (not shown).

The wafer W placed on the main table 3 can be heated or cooled within a temperature range of, e.g., −20° C. to +150° C. A test signal from the tester is transmitted to the probes 5A through the test head T and performance board. The test signal is applied to the electrodes of the wafer W from the probes 5A, and is utilized to test the electrical characteristics of a plurality of devices formed on the wafer W.

When testing the electrical characteristics of an object to be tested at a high temperature, a temperature adjusting mechanism (heating mechanism) in the main table 3 heats or cools the wafer to a predetermined temperature.

When the electrical characteristics of the object to be tested are to be tested, the object to be tested generates heat. Due to this heat, the printed wiring board 5B of the probe card 5 is thermally deformed. During high-temperature testing, the main table 3 is heated. Due to heat generated by the object to be tested or heating of the main table 3, the printed wiring board 5B is thermally deformed.

The reinforcing member 5D reinforces the printed wiring board 5B to suppress thermal deformation of the probe card 5. Jpn. Pat. Applin. KOKAI Publication No. 2000-67953 proposes a technique for bringing the distal ends of probes into contact with the electrodes of a device without changing the position of a probe card.

In the conventional probe card, the metal reinforcing member 5D prevents thermal deformation of the printed wiring board 5B. However, the reinforcing member 5D cannot suppress stress generated by thermal deformation completely. As is shown in FIG. 5B exaggeratedly, the probe card 5 warps downward as a result of thermal deformation and is bent. Consequently, the positions of the distal ends of the probes 5A are shifted to make the connection between the probes 5A and the object to be tested defective.

To thermally stabilize the probe card 5 before testing, the probe card 5 is preheated. Preheating, however, requires a long time, and decreases throughput.

According to one aspect of the present invention, there is provided a probe card that can decrease adverse effects of heat to electrically connect a contactor and an object to be tested more reliably. According to another aspect of the present invention, there is also provided a probe card that shortens the preheat time to accordingly increase the throughput.

BRIEF SUMMARY OF THE INVENTION

According to the first aspect of the present invention, there is provided a probe card which tests the electrical characteristics of an object to be tested. The probe card comprises:

a contactor;

a circuit board;

an intermediate member which is arranged between the contactor and circuit board and comes into contact with the contactor and circuit board flexibly and electrically; and

a connecting member which integrates the contactor and circuit board.

The probe card preferably comprises any one of the following (a) to (i) and, furthermore, some of the following (a) to (i) in combination.

(a) the intermediate member has a board and a plurality of elastically deformable contacts arranged at least on a circuit board side of the board.

(b) a reinforcing member which reinforces the circuit board.

(d) an elastic member arranged at least either between the contactor and circuit board or between the circuit board and reinforcing member.

(e) the intermediate member is attached to the elastic member arranged between the contactor and circuit board.

(f) the intermediate member is made of conductive rubber.

(g) the contactor has a ceramic board and a plurality of probes formed on an object-to-be-tested side of the ceramic board.

(h) as the intermediate member, a plurality of elastically deformable contacts which are provided on the contactor and come into electrical contact with the circuit board.

(i) a reinforcing member which reinforces the circuit board.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIGS. 1A to 1C are views schematically showing a probe card according to an embodiment of the present invention, in which FIG. 1A is a sectional view of the same, FIG. 1B is an enlarged sectional view of an intermediate member, and FIG. 1C is a plan view of a reinforcing member;

FIG. 2 is a view showing how the probe card shown in FIG. 1A is thermally deformed;

FIG. 3 is a view showing a probe card according to another embodiment of the present invention;

FIG. 4 is a partially cutaway front view of an example of a prober; and

FIGS. 5A and 5B are views showing a conventional probe card, in which FIG. 5A is a side view showing a probe card at room temperature, and FIG. 5B is a side view showing the probe card that has been thermally deformed.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described based on the embodiments shown in FIGS. 1A to 3. In the respective embodiments, the same or identical portions are denoted by the same reference numerals.

First Embodiment

A probe card 10 according to the first embodiment shown in FIGS. 1A to 1C can have a contactor 11, intermediate member 15, circuit board 12, connecting member 13, and reinforcing member 14. The intermediate member 15 can also be referred to as an “interposer”. The circuit board (to be also referred to as a “printed wiring board” hereinafter) 12 is electrically connected to the contactor 11. The connecting member 13 connects the contactor 11 and printed wiring board 12 to integrate them. The reinforcing member 14 reinforces the printed wiring board 12 integrated by the connecting member 13.

As shown in FIGS. 1A and 1B, the contactor 11 can have a ceramic board 11A, a plurality of probes 11B, terminal electrodes 11C, and connecting wirings 11D. The ceramic board 11A is made of, e.g., a ceramic material. The probes 11B are formed on the lower surface of the ceramic board 11A. The terminal electrodes 11C are formed on the upper surface of the ceramic board 11A. The connecting wirings 11D are formed in the ceramic board 11A to connect the terminal electrodes 11C and probes 11B to each other. The plurality of probes 11B are arranged such that their distal ends correspond to the layout of a plurality of electrodes (not shown) of at least one object to be tested (e.g., at least one device formed on the wafer).

The contactor 11 can be formed by a microprocessing technique such as a micromachine technique. The plurality of terminal electrodes 11C on the ceramic board 11A can be electrically connected to a plurality of terminal electrodes 12A on the printed wiring board 12 through the interposer 15.

The reinforcing member 14 can be formed of a metal having a low coefficient of linear expansion (e.g., a low-expansion alloy such as Invar), so that it will not expand much when it is heated during testing. The coefficient of linear expansion of Invar is approximately 2 ppm/° C. to 4 ppm/° C., which is much lower than that of a printed wiring board 12 made of a resin. FIG. 1C shows an example of the planar shape of the reinforcing member 14. The reinforcing member 14 can include, e.g., a ring 14a, disk 14b, and connectors 14c. The ring 14a is formed along the peripheral edge of the printed wiring board 12. The disk 14b is formed at the center of the ring 14a. The connectors 14c connect the ring 14a and disk 14b to each other. As the printed wiring board 12, a conventional resin printed wiring board can be used.

The interposer 15 can be provided between the contactor 11 and printed wiring board 12 to bring them into contact with each other flexibly and electrically. The interposer 15 absorbs thermal deformation of the printed wiring board 12, as will be described later. The interposer 15 shortens the preheat time of the probe card 10.

As shown in FIGS. 1A and 1B, the interposer 15 has a board 15A, a plurality of elastically deformable contacts 15B, a plurality of elastically deformable contacts 15C, and via hole conductors 15D. The board 15A is made of a ceramic material. The contacts 15B are formed on the upper surface of the board 15A. The contacts 15C are formed on the lower surface of the board 15A. The via hole conductors 15D electrically connect the contacts 15B and 15C to each other. The plurality of contacts 15B are arranged such that their distal ends correspond to the respective positions of the plurality of terminal electrodes 12A of the printed wiring board 12. The plurality of contacts 15C formed on the lower surface of the board 15A are arranged such that their distal ends correspond to the positions of the terminal electrodes 11C. The interposer 15 is fixed to the connecting member 13 through an elastic member 17 (to be described later).

The plurality of contacts 15B on the upper surface of the board 15A are arranged obliquely upward from the via hole conductors 15D. Terminals 15E at the distal ends of the respective contacts 15B come into electrical contact with the corresponding terminal electrodes 12A of the printed wiring board 12. The plurality of contacts 15C formed on the lower surface of the board 15A are arranged obliquely downward from the via hole conductors 15D. Terminals 15E′ at the distal ends of the respective contacts 15C come into electrical contact with the terminal electrodes 11C on the upper surface of the ceramic board 11A. The contacts 15B and 15C can be made of an elastic metal (e.g., tungsten) to be elastically deformable. The contacts 15B and 15C electrically connect the contactor 11 and printed wiring board 12 to each other, and absorb thermal deformation of the printed wiring board 12.

The upper and lower contacts 15B and 15C, respectively, reliably come into contact with the terminal electrodes 12A and 11C when the probe card 10 is thermally stable (state during testing). In other words, the terminal electrodes 12A of the printed wiring board 12 and the terminal electrodes 11C of the contactor 11 can be formed with such sizes that they can reliably come into contact with the terminals 15E and 15E′ of the contacts 15B and 15C of the interposer 15 even when the printed wiring board 12 has been thermally deformed to the maximum extant possible.

An elastic member 16 and the elastic member 17 made of rubber or the like can be mounted on and under the printed wiring board 12. The elastic member 16 can be arranged between the printed wiring board 12 and reinforcing member 14. The elastic member 17 can be arranged between the contactor 11 and printed wiring board 12. The elastic members 16 and 17 absorb thermal deformation of the printed wiring board 12 and stabilize the positions of the distal ends of the probes 11B.

The operation of the probe card 10 will be described with reference to FIG. 2. When performing high-temperature testing of an object to be tested by using the probe card 10, a main chuck is preheated prior to the testing, to thermally stabilize the probe card 10 or the like. A temperature adjusting mechanism incorporated in the main chuck (not shown) heats the main chuck to a predetermined temperature. During or after the heating, the main chuck is moved close to the probe card 10 to preheat it. When the temperature of the probe card 10 increases by preheating, of the probe card 10, the printed wiring board 12 having a higher coefficient of linear expansion than other members thermally expands much more than the other members. During the thermal expansion, the printed wiring board 12 is bound from around by the connecting member 13. Thus, heat stress of the printed wiring board 12 has no means of escape. As the printed wiring board 12 expands, it gradually bends downward, as shown in FIG. 2. The coefficients of linear expansion of the contactor 11 and reinforcing member 14 are much lower than that of the printed wiring board 12. Thus, the contactor 11 and reinforcing member 14 are thermally deformed only slightly and thus maintain their flatness.

As described above, of the probe card 10, only the printed wiring board 12 bends downward. The upper contacts 15B of the interposer 15 absorb the bending of the printed wiring board 12. The elastic members 16 and 17 absorb the thermal deformation of the printed wiring board 12. Hence, the thermal stress applied by the printed wiring board 12 to the contactor 11 decreases, and the flatness of the contactor 11 is maintained. The printed wiring board 12 is thermally deformed, and the upper contacts 15B of the interposer 15 are pushed downward. However, the contacts 15B are located within the surfaces of the terminal electrodes 12A of the printed wiring board 12, and the electrical contact of the contactor 11 and printed wiring board 12 can be maintained.

As described above, according to this embodiment, the contactor 11, printed wiring board 12, interposer 15, connecting member 13, and reinforcing member 14 are provided. The interposer 15 is provided between the contactor 11 and printed wiring board 12 to bring them into contact with each other flexibly and electrically. The connecting member 13 integrates the contactor 11, printed wiring board 12, and interposer 15. The reinforcing member 14 reinforces the printed wiring board 12 integrated through the connecting member 13. Thus, according to this embodiment, the printed wiring board 12 is thermally deformed to bend downward, thus applying a stress to the contactor 11. The elasticity of the interposer 15, however, can decrease the stress, and prevent the probes 11B of the contactor 11 from shifting from the corresponding electrode pads of the object to be tested. The probe card 10 is preheated to a test temperature, and the printed wiring board 12 is gradually thermally deformed. The interposer 15 brings the contactor 11 and printed wiring board 12 into electrical contact with each other reliably. Thus, the necessity of preheating the printed wiring board 12 until it stabilizes thermally is low. Consequently, the preheat time can be shortened in comparison with a conventional case, and the throughput can be increased.

According to this embodiment, as the interposer 15 has the elastically deformable contacts 15B and 15C, the thermal deformation of the printed wiring board 12 can be absorbed by the contacts 15B and 15C.

Second Embodiment

A probe card 10 of the second embodiment can have, as an intermediate member, a plurality of elastically deformable contacts 11E arranged on the upper surface of a contactor 11, as shown in, e.g., FIG. 3, in place of the intermediate member 15 shown in FIGS. 1 and 2.

The contacts 11E can be formed in the same manner as the contacts 15C of the interposer 15 shown in FIG. 1B. As shown in FIG. 3, the contacts 11E can be directly fixed to terminal electrodes 11C formed on the. upper surface of a ceramic board 11A of the contactor 11. The contactor 11 comes into electrical contact with terminal electrodes 12A of a printed wiring board 12 through the plurality of contacts 11E.

According to this embodiment, even when the printed wiring board 12 is deformed by thermal expansion, the thermal deformation can be absorbed by the contacts 11E of the contactor 11. This embodiment can provide the same operation and effect as those of the first embodiment. According to this embodiment, the structure of the probe card 10 can be simplified more than in the case of the first embodiment.

The present invention can be suitably utilized as a probe card for, e.g., a testing apparatus.

According to one embodiment of the present invention, there can be provided a probe card that can decrease the adverse effect of heat and reliably bring the contactor and object to be tested into electrical contact with each other.

According to another embodiment of the present invention, there can be provided a probe card that can shorten the preheat time and improve the throughput.

The present invention is not limited to the above embodiments. A probe card having, between a circuit board and contactor that form the probe card, an intermediate member which can absorb thermal deformation of the circuit board is incorporated in the present invention.

For example, when conductive rubber is used as the intermediate member, the same operation and effect as those of the above embodiments can be expected. The shape and material of the contacts are not particularly limited provided the contacts are elastically deformable and conductive.

Information

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CPC

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Abstract

Description

Claims

Priority Claims (1)