Probe for testing an electrical device

A probe having a first and a second arm portion extending between first and second connecting portions connecting the first and second arm portions respectively at their front end portion and base end portion, and a needle point portion below the first connecting portion. At least one of the entire first and second arm portions or the upper or lower edge portions of the first and second arm portions are arcuate.

CROSS-REFERENCE TO RELATED APPLICATION

This Application claims priority from International Application Number PCT/JP2003/11117, titled “Probe for Electric Test,”filed Aug. 29, 2003, and from Japanese Application Number 2003-134753, filed May 13, 2003.

FIELD OF ART

The present invention relates to a probe for use in electric test of a flat plate-like device under test such as a semiconductor integrated circuit.

BACKGROUND ART

A flat plate-like device under test such as a semiconductor integrated circuit is subjected to an electric test as to whether or not it is produced as per specification. This kind of electric test is conducted by using an electric connecting apparatus such as a probe card, a probe block, a probe unit or the like provided with a plurality of probes to be individually pressed against an electrode of the device under test. The electric connecting apparatus of this kind is used for electrically connecting the electrode of a device under test and a tester.

As probes for use in such an electric connecting apparatus, there are a needle type one produced from a conductive metal fine wire, a blade type one formed like a plate, and a probe element type one using a probe element which, forms a projected electrode in wiring formed on one face of an electrically insulated sheet (film).

The blade type probe includes a single plate type one produced from a conductive metal plate, and a lamination type one in which exposure and etching of a photoresist and plating its etched portion are made one or more times.

The probe of either type is supported in a cantilever-like manner on a support member such as a wiring plate with its needle point pressed against an electrode of a device under test. When the needle point is pressed against the electrode of the device under test, an over drive acts on the probe, which is curved by elastic deformation.

As one of the blade type probes, there is a Z-shaped one comprising: a first and a second arm portions extending in a second direction at an interval in a first direction; a first and a second connecting portions for connecting the first and second arm portions at their front end portions and base end portions; a needle point portion following one side in the first direction of the first connecting portion; and a mounting portion following the other side in the first direction of the second connecting portion (FIG. 1 of Japanese Patent Appln. Public Disclosure (KOKAI) No. 7-115110).

As another one of the blade type probes, there is one comprising: a first and a second arm portions extending in a second direction at an interval in a first direction; a connecting portion for connecting the first and second arm portions at their base end portions; a needle point portion following one side in the first direction of the front end portion of the first arm portion; and a mounting portion following the other side in the first direction of the front end portion of the second arm portion (FIG. 2 of Japanese Patent Appln. Public Disclosure (KOKAI) No. 2003-57264).

In each of the conventional probes, the mounting portion is attached to a proper support member and supported in a cantilever-like manner on the support member with its needle point pressed, in that state, against the electrode of the device under test. Thereby, the over drive acts on the probe, and the probe is curved by elastic deformation in the first and second arm portions.

In both these conventional probes, however, the first and second arm portions only extend in parallel to each other in the second direction which is diagonal to the first direction, so that, if an over drive amount is increased to greatly elastically deform the first and second arm portions, breaking occurs at least in one of the first and second arm portions.

Particularly, in case of a microprobe for an integrated circuit, the cross sectional areas of the first and second arm portions are remarkably small, so that a first and a second mechanical strengths are weak, and it is difficult to increase the over drive amount and elastically deform the first and second arm portions to a great extent.

Unless the over drive amount can be increased as mentioned above, pressing force (needle pressure) of the needle point against the electrode of the device under test cannot be increased, so that a good electrical connection between the electrode of the device under test and the needle point cannot be realized and the position of the needle point in the first direction should be coincided highly accurately. As a result, an accurate test cannot be expected.

DISCLOSURE OF THE INVENTION

An object of the present invention lies in making an over drive amount great to make the first and second arm portions greatly elastically deformable.

The probe according to the present invention comprises: a first and a second arm portions extending in a second direction at an interval in a first direction; a first and a second connecting portions for connecting the first and second arm portions at their front end portions and base end portions to each other; and a needle point portion following one side in the first direction of the first connecting portion or the second arm portion. In at least one of the first and second arm portions, at least one of the entire arm portion, one of edge portions in the first direction of the arm portion, and an edge portion the other side in the first direction of the arm portion is made arcuate.

The above-mentioned probe is supported in a cantilever manner at a support member on the side of the second connecting portion which connects the base end portions of the first and second arm portions, and the needle point is pressed against the electrode of the device under test in that state. When the needle point is pressed against the electrode, the over drive acts on the probe, whereby the first and second arm portions are elastically deformed to be curved.

In the above-mentioned probe, however, at least one of the first and second arm portions has at least one arcuate part, thereby increasing the mechanical strength of the first or the second arm portion having such an arcuate part. For this reason, even if a great over drive acts on the probe, both arm portions are elastically deformed and curved without causing a break in the first and second arm portions.

As a result, since the pressure of the needle point (needle pressure) against the electrode of the device under test can be increased by making the over drive amount great, it is possible to render the electrode of the device under test and the needle point in a state of good electrical connection, and to bring the electrode of the device under test and the needle point surely into contact without making the position of the needle point in the first direction coincide with a high accuracy, thereby enabling to carry out an accurate test.

The probe can further comprise a mounting portion located on the other side in the first direction relative to the first and second arm portions and an extended portion extending from the mounting portion to the one side in the first direction and following the second connecting portion. By this, the probe can be supported at the support member in the mounting portion.

The probe may have a shape of a plate whose thickness direction is a direction intersecting the first and second directions.

The mounting portion can have a hole penetrating in its thickness direction. By this, the through hole can be used as a positioning hole, thereby facilitating a work for mounting the probe on the support member.

The probe can further comprise a projection extending from the mounting portion toward the other side in the first direction. Thereby, by forming a hole for fitting the projection in the support member and inserting the projection into the fitting hole, positioning of the probe relative to the support member is carried out, thereby further facilitating the mounting work of the probe to the support member.

The needle point can comprise a pedestal portion following the first connecting portion and the first or second arm portion as well as a contact portion projecting from the one side in the first direction of the pedestal portion.

The contact portion may be made of a material different at least from that of the pedestal portion. The pedestal portion may be made of the same material as that of at least the first and second arm portions and the first and second connecting portions.

The contact portion may have a front end face which makes an angle from 0.1° to 5° to the second direction and of which a part nearer the side in the second connecting portion is nearer the side of the first connecting portion in the first direction.

The probe can further comprise a reference portion formed at a position different from the needle point of the needle point portion. By this, when positioning relative to a prober or the device under test, by picking-up image of the probe by an area sensor from the needle point side (the device under test side), and picture processing an output signal of the area sensor, the position of each probe can be obtained as a coordinate position of the needle point within a image picking-up region of the area sensor. As a result, since the probe has the reference portion formed at a position different from that of the needle point, the reference portion can easily identify from surroundings by using the output sensor of the area sensor, thereby easily determining the coordinate position of the reference portion, too. Also, since the positional relation between the reference portion and the needle point is constant, the position of the needle point can be easily determined from the position of the reference portion.

The reference portion can have a light reflection property in the first direction different from at least a part of a region next thereto. By this, the reference portion can be identified by using a difference in a reflected light amount in the other direction.

It is possible that the probe further comprises a projected portion projecting in the second direction from one of the needle point portion and the second arm portion, the projected portion has at least one inclined plane portion inclined to the axis of the projected portion and a flat plane portion following the front end of the inclined plane portion and perpendicular to the axis and retreated toward the arm portion side than to the needle point, and the reference portion is made the flat plane portion.

The projected portion may be projected from the needle point portion or the second arm portion. The reference portion can include a region enclosed by a surrounding region different in the light reflection property in the first direction.

The probe can further comprise at least one recess formed at the needle point portion, and a conductive coat formed in the recess and the needle point of the needle point portion. By this, wear of the needle point can be reduced by making the coat of a harder material and another portion such as the needle point. Also, since a coat is formed in the recess, too, even if the needle point portion slides against the electrode in a state of being pressed against the electrode due to an over drive at the time of an electric test, the coat can be prevented from peeling off the needle point portion.

THE BEST MODE FOR WORKING THE INVENTION

Hereinafter, inFIG. 1A, it is defined that the upward and downward direction is the first direction, the rightward and leftward direction the second direction, and the direction perpendicular to the surface of the paper the third direction, but those directions differ according to a chuck top of the prober which receives a device under test to be excited.

Referring toFIGS. 1A and 1B, the probe10includes: a first and a second arm portions12,14extending in the second direction (rightward and leftward) at an interval in the first direction (upward and downward); a first and a second connecting portions16,18for connecting the first and second arm portions12,14at their front end and base end portions; a needle point portion20following one side (lower edge side) in the first direction of the first connecting portion16; a mounting portion22located on the other side (upper edge side) in the first direction to the first and second arm portions12,14; and an extended portion24extending toward one side in the first direction from the mounting portion22and following the second connecting portion18.

The needle point portion20is provided with a pedestal portion26integrally following the lower edge portion of the first connecting portion16and the lower edge portion on the front end side of the second arm portion14, and a contact portion28projecting from the lower edge portion of the pedestal portion26.

The arm portions12,14, the first and second connecting portions16,18, the mounting portion22, the extended portion24and the pedestal portion26are shaped as an integral plate having substantially the same thickness dimension, so that the probe10is made a generally flat blade-type probe.

On the other hand, the contact portion28has a truncated conical or truncated pyramidal shape, and is integrally formed on the underside of the pedestal portion26at corresponding parts of the bottom face of such a conical or pyramidal shape.

The contact portion28has a front end face having an angle θ from 0.1° to 5° to an imaginary horizontal plane which is perpendicular to the upward and downward direction. In the illustration, this front end face acts as a needle point30to be pressed against the electrode of the device under test.

The needle point (front end face)30is an inclined plane in which the side (front end side) of the first connecting portion16in the rightward and leftward direction is the upper side. The needle point30may, however, be made a horizontal plane perpendicular to the upward and downward direction, or a hemispherical plane. Also, the needle point30may be an acute needle point instead of a plane.

The first arm portion12is generally made arcuate having a proper radius of curvature R1and projecting upward. The radius of curvature R1may have a value corresponding to an interval H between the arms12and14in the upward and downward direction, an interval W between the connecting portions16and18in the rightward and leftward direction, and a distance (effective length of the arm portion) L from the second connecting portion18to the center of the contact portion28, as well as corresponding to a slipping amount of both when the needle point30is pressed against the electrode of the device under test.

As a material of the probe10can be given a conductive metal material such as an alloy of nickel and phosphor (Ni—P), an alloy of nickel and tungsten (Ni—W), rhodium (Rh), phosphor bronze (BeCu), nickel (Ni), an alloy of palladium and cobalt (Pd—Co), and an alloy of palladium, nickel and cobalt (Pd—Ni—Co) or the like.

The probe10may be entirely made of the above-mentioned material. The contact portion28, however, may be made of a different material at least from that of the pedestal portion26. In this case, the pedestal portion26may be made of the same material as those of both arm portions12,14, both connecting portions16,18, the mounting portion22and the extended portion24, or different material therefrom.

Production of the probe10is facilitated if the probe10is made of the same material in its entirety or generally except the contact portion28.

The probe10is assembled into an electric connecting apparatus80such as a probe card, as shown inFIGS. 15 through 19described later. The electric connecting apparatus80is detailed later, but is briefly explained in the following.

The electric connecting apparatus80has a circular wiring plate82connected to a tester, a circular reinforcing plate84disposed on the top face of the wiring plate82, and a ring86disposed on the underside of the wiring plate82attached coaxially in an overlapped state with a plurality of bolts88. A circular connection plate90and a mounting plate92are disposed inside the ring86and on the lower side of the wiring plate82.

The wiring plate82, ring86, connection plate90and mounting plate92act as support members, i.e., support plates of the probe10. A device under test94like an integrated circuit on a semiconductor wafer is disposed and supported horizontally on a chuck top96of an inspection stage.

The probe10is supported at the mounting portion22in a cantilever manner on the mounting plate92, and is pressed in that state against the electrode of the device under test94. When the needle point30is pressed against the electrode of the device under test94, the over drive acts on the probe10to cause both arm portions12,14to be elastically deformed and curved.

In the probe10, however, since the first arm portion12is generally curved to be arcuate, mechanical strength of the arcuate first arm portion12is increased. For this reason, even if a great over drive acts on the probe10, both arm portions12,14are elastically deformed and curved without breaking.

As a result, since the pressure (needle pressure) of the needle point30against the electrode of the device under test94can be increased by making the over drive amount greater, a favorable electric connection between the electrode of the device under test94and the needle point30can be achieved.

Also, to conduct an electric test of the device under test94, a plurality of probes10having such a structure as mentioned above are attached to the support member (in particular, the mounting plate92). In this case, even if the positions of the needle points30in the upward and downward direction of adjoining probes10do not coincide with high accuracy, it is possible to conduct accurate inspection by increasing the over drive amount to elastically deform the probes to become the greater, the nearer the electrode of the device under test94, and bringing the electrode of the device under test94and the needle points30surely into contact.

Referring toFIGS. 2A and 2B, the mounting portion22may have holes32penetrating in its thickness direction at a plurality of positions at intervals in the rightward and leftward direction, or may form projections34extending upward from the mounting portion22at a plurality of positions at intervals in the rightward and leftward direction.

According to the probe10having holes32in the mounting portion22, the holes32can be used as positioning holes of the probes10relative to the mounting plate92, thereby facilitating a work for mounting the probes10on the mounting plate92.

Also, according to the probe10having projections34extending upward from the mounting portion22, probes10are positioned relative to the mounting plate92by forming holes for fitting projections in the mounting plate92and inserting the projections34in the fitting holes, thereby facilitating mounting work of the probes10on the mounting plate92.

As shown inFIG. 3, in place of curving the first arm12into an arc shape, the second arm portion14may be curved into an arc shape which projects upward with a proper radius of curvature R2. By this, since the mechanical strength of the second arm portion14becomes greater, even if a great over drive acts on the probe10, both arm portions12,14are elastically deformed and curved without breaking.

As shown inFIG. 4, the first and second arm portions12and14may be curved into an arc shape projecting upward with proper radii of curvature R1and R2, or as shown inFIG. 5, the second arm portion14may be curved into an arc shape projecting downward with the proper radius of curvature R2, or further as shown inFIG. 6, the first and second arm portions12and14may be curved into an arc shape projecting downward with proper radii of curvature R1and R2.

In any of the probes shown inFIGS. 4,5and6, mechanical strength of the second arm portion14becomes greater, so that even if a great over drive acts on the probe10, both arm portions12,14tend to be easily elastically deformable without breaking.

In any of the above embodiments, the width dimension of the pedestal portion26in the rightward and leftward direction may be made the same as the width dimension of the first connecting portion16in the rightward and leftward direction, or as shown inFIG. 7, the length dimension of the first and second arm portions12and14in the rightward and leftward direction may be made the same. In particular, according to the latter, the second arm portion14is easily elastically deformed, so that even if a great over drive is made to act on the probe10, both arm portions12,14are more surely elastically deformed without breaking.

In any of the above embodiments, in place of integrally forming the contact portion28on the underside of the pedestal portion26at a corresponding position on its conical or pyramidal bottom face, it is possible, as shown inFIGS. 8A and 8B, to make the contact portion28independently at least from the pedestal portion26and adhere the contact portion28to the underside36of the pedestal portion26by a conductive adhesive such as solder at a position corresponding to the conical or pyramidal bottom face.

As shown inFIGS. 9A and 9B, it may be a plate-like contact portion38having a trapezoidal shape generally with the same thickness. The probe10shown inFIGS. 9A and 9Bcan be made as shown inFIGS. 10A-10F.

Firstly, as shown inFIGS. 10A and 10B, a plate40is prepared, a photoresist42is applied to the plate40, a region of the photoresist42corresponding to a probe region other than the contact portion38is exposed and developed, a recess is formed in the exposed and developed region, and a conductive metal material is filled in the recess by electroplating using electroforming.

Next, as shown inFIGS. 10C and 10D, a photoresist46is applied to the photoresist42and a filler44, a region of the photoresist46corresponding to a front end region including the contact portion38is exposed and developed, a recess is formed in the exposed and developed region, and a conductive metal material is filled in the recess by electroplating using electroforming.

Then, as shown inFIGS. 10E and 10F, a photoresist50is applied to the photoresist46and a filler48, a region of the photoresist50corresponding to a probe region other than the contact portion38is exposed and developed, a recess is formed in the exposed and developed region in the photoresists46and50, and a conductive metal material is filled in the recess by electroplating using electroforming.

Thereafter, all the photoresists42,46and50are removed, the probe10integrated with fillers44,48and52is detached from the plate40.

In place of making the contact portion28conical or pyramidal, a semi-cylindrical contact portion56elongated in the thickness direction of the probe10as shown inFIG. 11may be used. The contact portion56has a trapezoidal shape as viewed from the thickness direction of the probe10. The probe10with the contact portion56can be also made easily by conducting several times exposing and developing of the photoresist and electroplating such as mentioned above.

The probe for electric test is generally positioned to the prober or device under test in a state of being disposed on the prober. For this reason, an image of the probe10is picked-up by an area sensor from the side (side of the device under test) of the needle point30. The position of each probe10is obtained as a coordinate position of the needle point30within an image picking-up region of the are a sensor by image-processing an output signal of the area sensor.

Therefore, the probe10has a reference portion60, as shown inFIG. 12, at a position different from that of the needle point30. The reference portion60shown inFIG. 12forms a recess62on the underside of the pedestal portion26and forms a projecting portion64projecting downward from the pedestal portion26and is made a flat face portion of the lower end of the projecting portion64.

The projecting portion64extends in the thickness direction of the probe10and is made to have a trapezoidal cross section by the flat face portion, i.e., reference portion60and a pair of right and left inclined plane portion66which is inclined to the axis of the projecting portion64.

The reference portion (flat face portion)60follows the front ends of both inclined plane portions66and is made perpendicular to the axis of the projecting portion64, and retreated toward the arm portion14than toward the needle point30, and further shaped like a strip extending in the thickness direction of the probe10.

When positioning relative to the prober or the device under test, the image of the probe10is picked-up by the area sensor from the side (side of the device under test) of the needle point30. The position of the probe10is obtained as a coordinate position of the needle point within the image picking-up region of the area sensor by image-processing an output signal of the area sensor.

Since the probe10shown inFIG. 12has the reference portion60formed at a position different from that of the needle point30, it is possible to distinguish the reference portion60easily from the surroundings by using an output signal of the area sensor, thereby enabling to determine easily the coordinate position of the reference portion60. Also, since the positional relation between the reference portion60and the needle point30is constant, the position of the needle point30can be easily determined from the position of the reference portion60.

The reference portion60, being the flat face portion, has a downward light reflection property different from at least a part of the neighboring region. For this reason, it is possible to determine the reference portion60easily by utilizing a difference in the amount of downward reflection light.

Referring toFIG. 13, the probe10has the projected portion64projected downward from the right end portion of the arm portion14, making the flat face portion at the lower end of the projected portion64the reference portion60.

Referring toFIG. 14, the probe10forms a surrounding region68on the underside of the pedestal26, making the region inside the surrounding region68a reference portion70. The reference portion70is higher in the downward light reflection property than the surrounding region68and is a flat face. The surrounding region68is made a coarse face to reflect a light irregularly.

While the surrounding region68is circular in the illustration, it may have another shape, such as a triangle, a rectangle or an asterisk. Also, the surrounding region68and the reference portion70may be formed on the underside of the arm portion14instead of the pedestal portion26.

The reference portions60and70may be made acute portions in place of flat faces. Also, it suffices that the reference portions60and70differ in the downward light reflection property from that of the surrounding or neighboring region66,68. Accordingly, the reference portions60and70may be made larger or smaller than the surrounding or neighboring region66,68in the downward light reflection property.

Both of the probes10shown inFIGS. 13 and 14bring about the same action and effect as the probe shown inFIG. 12.

It suffices that the reference portion60or70of any probe10shown inFIGS. 12,13and14has higher or lower light reflection property than its neighboring region, but it is preferable that the light reflection properties be greatly different between the reference portion60or70and its neighboring region. Therefore, the reference portion60or70may be made a flat face and its surrounding region may be made an inclined plane inclined to the reference portion, an irregular light-reflection plane, a low light-reflection plane, etc.

While in any of the above embodiments, the whole of the arm portion12or14is curved in an arc-like shape, it is possible to make at least one of the edge portion on one side in the upward and downward direction of the arm portion12or14and the edge portion on the other side in the upward and downward direction of the arm portion12or14may be made arcuate.

Any probe shown inFIGS. 1-7andFIGS. 11-14can also be produced like the probe shown inFIG. 7by the technique shown inFIG. 8.

In the following, embodiments of an electric connecting apparatus using the above-mentioned probe are explained.

Referring toFIGS. 15-19, as already mentioned, an electric connecting apparatus80has a circular wiring plate82, a circular reinforcing plate84disposed on the top face of the wiring plate82, and a ring86disposed on the underside of the wiring plate82coaxially attached with a plurality of bolts88in an overlapped state. Inside the ring86, a circular connecting plate90and a mounting plate92are disposed on the underside of the wiring plate82.

The wiring plate82is provided at the peripheral edge portion of the top face a plurality of tester lands100connected to an electric circuit of a tester, and though not shown, a plurality of wiring portions individually connected to the tester lands on the underside or the inside.

The reinforcing plate84has a circular hole102at the central portion and a plurality of crescent-shaped holes104provided therearound. The ring86has a plurality (three in the drawing) of plate-like holding portions106extending horizontally from the lower end edge toward the center so as to receive the mounting plate92in the inside at equal angular intervals about the axis of the ring86.

The wiring plate82, the reinforcing plate84and the ring86are positioned relatively by a plurality of positioning pins108penetrating them in the thickness direction.

The connecting plate90has a plurality of first connection lands110formed on its underside, solders a plurality of connection members112individually to the first , connection lands110, and connects the connection lands110to the wiring portions of the wiring plate82by a plurality of wiring portions (not shown).

The connecting plate90is attached to the wiring plate82in a state of being pressed against the wiring plate82with proper fasteners such as bolts. The wiring plate82, the ring86and the connection plate90constitute a support plate for probes114. The connection plate90may be integrated with the wiring plate82.

Each connection member112in the drawing is the probe shown inFIGS. 1A and 1BorFIGS. 2A and 2B, and is soldered in a cantilever-like manner to the corresponding first connection land110at the mounting portion22such that a needle point portion20faces downward and that the arm portions12,14extend in the rightward and leftward direction.

The mounting plate92has a circular flange portion formed in the outer peripheral portion of the upper end of its circular body portion, and a plurality of probes114attached to the underside. The mounting plate92is provided with a plurality of second connection lands116to be pressed individually against the connection members112, and a plurality of wiring portions120connecting the second connection lands116and probe seats118in one-to-one correspondence.

Each probe114is the probe shown inFIGS. 1A and 1BorFIGS. 2A and 2B, and is soldered in a cantilever-like manner to the corresponding probe seat118at the mounting portion22such that the needle point portion20faces downward and that the arm portions12,14extend laterally.

The mounting plate92is incorporated into the ring86by a plurality (three in the drawing) of positioning plates122attached at equal angular intervals to the underside of the ring86with bolts124in a state of being placed on the holding portion106with the second connection lands116pressed against the needle point portions20of the corresponding connection members112.

Each positioning plate122is positioned relative to the ring86, in turn, to the wiring plate82with a positioning pin126. Each positioning plate122can be a spring leaf so as to energize the mounting plate92toward the connection plate90or to elastically deform when the probe114is pressed against the device under test94.

The mounting plate92is mounted on the top face of the positioning plate122with a plurality of bolts128and positioned relative to each positioning plate122with a positioning pin130.

The mounting plate92is energized toward the holding portion106by means of the connection members112, thereby being relatively pressed against each second connection land116and the needle point portion20of the corresponding connection member112.

The positioning plate122is positioned at equal angular intervals about the axis of the ring86, thereby making the pressing forces of the second connection lands116against the connection members112the same.

Instead of attaching the probe-like connection members112to the first connection land110such that the needle points20are projected downward, they may be attached to the second connection land116such that the needle points20are projected upward to be brought into contact with the first connection land110.

The electric connecting apparatus80has the needle point30of each probe114pressed against the electrode of the device under test94, as shown inFIG. 19. By this, the over drive acts on each probe114, and both arm portions12,14are elastically deformed and curved.

A plurality of probe-like connection members112disposed in a cantilever-like manner between the connection plate90and the mounting plate92are, as shown inFIG. 19, curved at the cantilever-like arm portions12,14when the probe114and the device under test94are pressed, and absorb a part of the force to be transmitted to the connection plate90, in turn, to the wiring plate82when the probe114and the device under test94are pressed. This reduces the force to be transmitted to the connection plate90and the wiring plate82when the probe114and the device under test94are pressed.

In particular, as the connection member112and probe114, if, like the probes shown inFIGS. 1 through 14, the probe10of which one of the arm portions12,14is made arcuate at least at the whole of the arm portion, the upper edge portion of the arm portion, and the lower edge portion of the arm portion is used, the mechanical strength of the arm portion having an arcuate portion becomes great as mentioned above, so that even if a great over drive acts on the probe, both arm portions are elastically deformed and curved without breaking.

As a result, since, by making the amount of over drive great, the pressing force (needle pressure) of the needle points against the electrode of the device under test94can be made great, the electrode of the device under test94and the needle point can be rendered into a state of favorable electric connection, and the electrode of the device under test94and the needle points can be surely brought into contact without making the positions of the needle points in the upward and downward direction coincide with high accuracy, which results in an accurate testing.

Referring toFIG. 20, the probe10further includes the recess72formed in the pedestal portion26of the needle point portion20, and the conductive coat74formed in a region containing the recess72and the needle point30of the needle point portion20.

Though the recess72is shown as a hole penetrating the pedestal portion26, it may be a bottomed hole. In that case, such bottomed holes may be formed at a plurality of positions such as both faces in the thickness direction of the pedestal portion26, at the front end face and the rear end face of the pedestal portion26, the bottom face of the pedestal portion, etc.

The coat74may be formed not only in such a region as mentioned above, but also on the whole body of the needle point portion20, or in a region including the above-mentioned region and another region containing the whole needle point portion20, the arm portion14and the connecting portion16, the entire probe.

According to the probe having the coat74, by making the coat74of a harder material than other portions such as the needle point portion20, ware of the needle-point30can be reduced. Also, since the coat74is formed in the recess72, too, the coat74is prevented from peeling off the needle point portion20even if, due to an over drive at the time of an electric test, the needle point30slides relative to the electrode in a state of being pressed against the electrode of the device under test.

The present invention is not limited to the above embodiments but can be variously modified without departing from its purport.