1. Field of the Invention
The present invention relates to a probe (in particular, a cantilever type probe) , a probe card, and a testing device. More particularly, the present invention relates to a probe, a probe card, and a testing device, especially suitable for testing a through hole (a via or a contact hole) to be filled with conductor, and which is provided in a circuit board, a wafer, or the like (hereinafter, referred to as “circuit board”).
2. Description of the Related Technology
As illustrated in
The conventional cantilever type probe 153 has, as illustrated in
In performing a test on the circuit board 150 using the probe card 152, the contact portion 154 of the probe 153 is brought into contact with the wiring 151 of the circuit board 150, and the probe card 152 further descends by a small distance. This makes the probe 153 elastically deformed to cause the contact portion 154 to slide a little over the wiring 151 in a longitudinal direction (in an X direction in
At this time, an oxide film formed on a surface of the wiring 151 is scraped off by the rectangular portion 155 of the contact portion 154, thereby attain stable electrical contact between the contact portion 154 of the probe 153 and the wiring 151.
However, when the probe card 152 having the conventional cantilever type probe 153 is used for testing a through hole provided in a circuit board and to be filled with the conductor to test how well it is filled with conductor the following problem arises.
It should be noted that, descriptions of the conventional probe will be made on the premise that plating 160 is provide to an inner surface of the through hole 158 and a rear surface 150b of the circuit board 150. In reality, a front surface 150a and the rear surface 150b of the circuit board are provided with wiring connected thereto.
By providing the contact hole 157, the wiring (not shown) provided on the front surface 150a and the rear surface 150b of the circuit board 150 can be electrically connectable. Further, a space between the front surface 150a side and the rear surface 150b side of the circuit board 150 can be kept as hermetic.
When the probe card 152 is used for testing how well the contact hole 157 is filled with the conductor 159, the probe card 152 and the probe 153 are disposed, for example, on the side of the front surface 150a of the circuit board 150. Then, the contact portion 154 of the probe 153 is brought into contact with the conductor 159. With this state, the resistance between the front surface 150a and the rear surface 150b of the conductor 159 and the resistance of a plating 160 provided on the inner periphery of the through hole 158 are measured with the probe 153.
At this time, when the through hole 158 of the contact hole 157 is completely filled with the conductor 159, electric current for the measurement flows through both the plating 160 provided on the inner surface of the through hole 158 and the conductor 159, which relatively reduces the resistance.
On the other hand, when the through hole 158 is hardly filled with the conductor 159 as illustrated in
Therefore, when the through hole 158 is hardly filled with the conductor 159, the resistance is relatively high as compared with a case where the through hole 158 is completely filled with the conductor 159. When only a part of the through hole 158 is filled with the conductor 159, the resistance is higher than that when the through hole 158 is completely filled with the conductor 159, and lower than that when the through hole 158 is hardly filled with the conductor 159.
Here, when the through hole 158 of the contact hole 157 is hardly filled with the conductor 159 or only a part of the through hole 159 is filled with the conductor 159 as described above, there is a possibility that the contact portion 154 of the probe 153 enters the through hole 158 as illustrated in
When the contact portion 154 of the probe 153 has entered he through hole 158 as described above, there is a possibility that the contact portion 154 might be brought into contact with the lower portion side of the plating 160 in the through hole 158 or with a support 161 for supporting the circuit board 150, provided that the thickness t of the circuit board 150 is thin or the length of the contact portion 154 of the probe 153 is relatively longer with respect to the thickness t of the circuit board 150 (as shown by a broken line).
In such a case, the resistance measured by using the probe card 152 is lower than the actual resistance. More specifically, a problem arises that, although the through hole 158 is hardly filled with the conductor 159 or the through hole 158 is only partly filled with the conductor 159, the result of measuring the resistance would be similar to that of a case where the through hole 158 is completely filled with the conductor 159. As described above, the conventional probe 153 has a problem that it can not accurately measure how well the through hole 158 is filled with the conductor 159.
The present invention has been made in view of the above-mentioned problem, and an object is to provide a probe, a probe card, and a testing device for precisely testing the state of a hole provided in a circuit board, in particular, how well a through hole provided in a circuit board and being to be filled with conductor, is filled with conductor.
In order to achieve the above object, the present invention adopts the following devices.
Examples of the above-described hole include a through hole and a contact hole. According to the present invention, even when a hole in a circuit board where conductive wiring is to be provided is hardly filled with the conductive wiring, or, when the hole is only partly filled with the conductive wiring, the contact portion of the probe can be prevented from entering the hole. Therefore, conductivity in the conductive wiring in the hole can be precisely tested.
(2) Examples of the contact portion include the one in the shape of an arc having a radius of curvature larger than a radius of the hole.
(3) Examples of the contact portion also include the one linear in shape which is in parallel with a surface of the circuit board to be tested and is longer than a diameter of the through hole.
(4) Further, the present invention is a probe card having a probe to be brought into contact with the conductive wiring for performing a test for conductivity of the conductive wiring in a hole, such as a through hole or a contact hole, provided in a circuit board,
(5) Further, a testing device of the present invention comprises:
As described above, according to the present invention, a contact portion of a probe can be prevented from getting in a hole provided in a circuit board. In particular, even when the through hole in a circuit board is hardly filled with conductor or the through hole is only partly filled with conductor, the contact portion of the probe can be prevented from entering the through hole. Therefore, it is possible to precisely test how well the through hole is filled with the conductor.
Hereinbelow, embodiments of a probe, a probe card, and a testing device according to the present invention will be described in detail with reference to the drawings.
It should be noted that, in this embodiment, the through hole 22 is filled with the conductor 21 to form a contact hole (VIA).
The probe 10 is provided with an elastically deformable leg portion 11 diagonally extending from the probe card 1, a bent portion 12 which is provided on a tip side of the leg portion 11 and extends to the circuit board 20 side, and a contact portion 13 provided on a tip side of the bent portion 12.
As illustrated in
In this embodiment, the contact portion 13 is formed to have an arc-shape. Here, d1 denotes the diameter of the through hole 22 and r1 denotes the radius of the through hole 22, and when it is r1=d1/2, a contact surface 13a, which is an outer peripheral. surface of the contact portion 13, has a radius of curvature r2 which is larger than the radius r1 of the through hole 22 (r2>r1)
The contact portion 13 is disposed over the through hole 22 to test how well the through hole 22 is filled with the conductor 21. It should be noted that a tip 13b of the contact portion 13 is disposed outside the through hole 22.
The bent portion 12 is formed by bending a tip side of the leg portion 11 in a direction away from the probe card 1 so as to form an appropriate angle. Further the contact portion 13 is formed by bending a tip side of the bent portion 12 in a direction toward the probe card 1 so as to form an arc.
When the through hole 22 is not filled with the conductor 21 (see
As illustrated in
In the case to where the conductive state (filled state) of the conductor 21 in the through hole 22 provided in the circuit board 20 is tested by the probe card 1 provided the probe 10, the contact portion 13 of the probe 10 is disposed over the through hole 22 and the conductor 21 as illustrated in
Here, when the through hole 22 is completely filled with the conductor 21, the contact portion 13 is brought into contact with the conductor 21. In this case, the resistance of a plating 23 and the resistance between the upper surface 20a and the lower surface 20b of the conductor 21 measured by the probe card 1 are relatively small. From this result of the measurement, it can be determined that the through hole 22 is completely filled with the conductor 21.
Further, as illustrated in
In this case, electric current for the measurement which flows between the probe 10 and the rear surface 20b of the circuit board 20 passes through only the plating 23 in the through hole 22. Accordingly, the resistance between the upper end surface 20a and the lower end surface 20b of the plating 23 is longer than that of a case where the through hole 22 is completely filled with the conductor 21. From this result, it can be determined that the through hole 22 is hardly filled with the conductor 21.
Further, as illustrated in
Therefore, the resistance between the upper end surface 20a and the lower end surface 20b of the plating 23 measured by the probe card 1 is longer than that of a case where the through hole 22 is completely filled with the conductor 21, and smaller than that of a case where the through hole 22 is hardly filled with the conductor 21. From the result of the measurement, it can be determined that the through hole 22 is only partly filled with the conductor 21.
Further, as described above, the probe 10 of the present invention is provided with the abrasion marks 14 over the contact surface 13a of the contact portion 13 which is to be brought into contact with the circuit board 20.
Therefore, when the probe card 1 descends to cause the contact portion 13 to slide in a longitudinal direction Y of the probe 10 as illustrated in
This makes it possible to attain stable electrical contact between the contact portion 13 of the probe 10 and the conductor 21.
The probe 30 has a leg portion 11, a bent portion 12, and a linear contact portion 33. The contact portion 33 is made of a material having an electrical conductivity. The contact portion 33 is fixed to a tip of the bent portion 12 by means of using an electrically conductive adhesive or welding.
Further, the contact portion 33 is disposed substantially in parallel with a surface 20a to be tested of a circuit board 20. The length L of the contact portion 33 is longer than the diameter dl of a through hole 22 in the circuit board 20.
Further, as illustrated in
In a case where a test is performed for conductive state (filled state) of a conductor 21 in the through hole 22 of the circuit board 20 by a probe card 1 having the probe 30, the contact portion 33 of the probe 30 is disposed over the through hole 22 of the circuit board 20 and over the conductor 21 as illustrated in
Accordingly, the contact portion 33 of the probe 30 is prevented from entering in the through hole 22 even when the through hole 22 of the circuit board 20 is hardly filled with the conductor 21 or when the through hole 22 is only partly filled with the conductor 21.
Therefore, it is possible to perform a test for conductive state (filled state) of the conductor 21 accurately even is the case where. the through hole 22 is completely filled with the conductor 21, where the through hole 22 is hardly filled with the conductor 21, or where the through hole 22 is only partly filled with the conductor 21.
The contact portion 43 is formed by bending a tip side of the bent portion 12 so as to be in parallel with a probe card 1. The length L of the contact portion 43 is formed to be longer than the diameter d1 of a through hole 22.
As illustrated in
In a care where a test is performed for conductive state (filled state) of the conductor 21 in the through hole 22 of the circuit board 20 by a probe card 1 having the probe 40, the contact portion 43 of the probe 40 is disposed over the through hole 22 in the circuit board 20 and the conductor 21. A tips surface 43b of the contact portion 43 is disposed outside the through hole 22.
The contact portion 43 of the probe 40 can be prevented from entering in the through hole 22 even when the through hole 22 is hardly filled with the conductor 21 or the through hole 22 is only partly filled with the conductor 21. Therefore, it is possible to perform a test for conductive state of the conductor 21 in the through hole 22 with precision.
The contact portion 53 is provided with the bent portion 12 having the tip thereof formed to be hemispherical. A radius of curvature r3 of the contact portion 53 is larger than the radius r1 of the through hole 22 in the circuit board 20 (r1=d1/2).
Further, as illustrated in
In a care where a test is perform for conductive state (filled state) of conductor 21 in the through hole 22 of the circuit board 20 by a probe card 1 having the probe 50, the contact portion 53 is disposed over the through hole 22 and the conductor 21.
Here, as illustrated in
Further, when the through hole 22 is hardly filled with the conductor 21 as illustrated in
Accordingly, the contact portion 53 is prevented from entering in the through hole 22. Therefore, it is possible to test how well the through hole 22 is filled with the conductor 21, accurately.
It should be noted that the contact surface 53a of the contact portion 53 may be a flat surface which is in parallel with a surface 20a of the circuit board 20 as illustrated in
By forming the contact surface 53a of the contact portion 53 is a flat surface, even when the contact portion 53 is misaligned with the through hole 22 to some extent, it is possible to bring the contact surface 53a into contact with the conductor 21 in the through hole 22, which makes it possible to perform the test precisely.
While, in the above first to fourth embodiments, the cases where the plating 23 is formed on the rear surface 20b of the circuit board 20 and on the inner surface of the through hole 22 are described, there is another case where the plating 23 is formed only on the inner surface of the through hole 22 as illustrated in
In this case, the probe card 1 (see
The probe card 1 is provided with the probe 10 of the first embodiment. It should be noted that the probe card 1 may also be provided with, instead of the probe 10, the probe 30, 40, or 50 of the second, third, fourth, or fifth embodiment described above.
Further, in this embodiment, a plurality of chips are provided on the circuit board 20 and a plurality of through holes 22 are provided in each chip. A case where all the through holes in each chip are simultaneously tested will be described.
Here, first, the circuit board 20 is mounted on a predetermined position of the mechanism portion 61 and is held by the vacuum chuck (S101) Next, the circuit board 20 is moved to a center position and position adjustment is made in X, Y, and Z directions (S102). Then, adjustment of the rotational position of the circuit board 20 (θ adjustment) is made (S103)
This adjustment of the rotational position is made in order to align an arrangement of the plurality of through holes 22 provided in the circuit board 20 with an arrangement of the plurality of probes 10 of the probe card 1. The adjustment is made based on the result of detection performed by the alignment mark detecting device 63.
When it is determined that the predetermined number M is m (S104), the Z stage ascends. When the through hole 22 is completely filled with the conductor 21, the contact portion 13 of the probe 10 is brought into contact with the conductor 21 in the through hole 22. When the through hole 22 is hardly filled with the conductor 21 or when the through hole 22 is only partly filled with the conductor 21, the contact portion 13 of the probe 10 is brought into contact with plating 23 provided on the inner surface of the through hole 22 (S105).
Then, the number n of the tests (n=1, 2, 3, . . . ) is set based on a predetermined number N (S106). Next, the resistance between the upper end surface 20a and the lower end surface 20b of the conductor 21 and the resistance of the plating 23 provided on the inner periphery of the through hole 22 are measured by the measuring device 64 (S107). Then, the result of measurement is stored in a database or the like (S108).
Further, it is determined whether a predetermined number M is 0 or not (S109). When the predetermined number M is 0, the resistance is measured in the above step (S107).
When the predetermined number M is not 0, the stage further descends (S110). Next it is determined whether measurement of the resistance is completed or not with respect to all the chips on the circuit board 20 (S111).
When it is determined in the above step (S111), that the test is completed on all the chips, the circuit board 20 is moved to a replacement position (S112). Further, the test result is displayed on the personal computer 65. This is the end of the test on one circuit board 20.
When it is determined in the above step (S111), that the test is not completed on all the chips, then, the processes are repeated from the above step (S104).
Accordingly, the testing device 60 of a circuit board or the like according to the present invention can test states of conductivity of the conductor 21 is many through holes 22 provided in the circuit board 20 and to be filled with the conductor 21, simultaneously and accurately. Therefore, the test on the circuit board 20 can be completed in a short time.
It should be noted that, although the above first to sixth embodiments describe the cases where the present invention is applied to a circuit board having a through hole in which the conductive wiring is provided, the present invention is also applicable to a wafer having a hole in which the conductive wiring is to be provided or the like.
<Others>
The disclosures of Japanese patent application No.JP2006-042313 filed on Feb. 20, 2006 including the specification, drawings and abstract are incorporated herein by reference.
Number | Date | Country | Kind |
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JP2006-042313 | Feb 2006 | JP | national |