IE20200242A1 - Probing method having alignment correcting mechanism and probe card - Google Patents

Abstract

A probing method includes the steps of aligning an image origin of an image capturing device with a probing end of a probe of a probe card and a target point of a first electric contact of a device under test along a vertical axis, obtaining an original reference point position of the probe card in a way that the image origin is kept aligned with the target point and the probing end along the vertical axis, probing the first electric contact, and before later probing of every other electric contact, moving the device under test to intend aligning the image origin with a target point of the electric contact, obtaining a positional error between the target point and the image origin and performing alignment correction by moving the probe card according to the original reference point position and the positional error for maintaining great testing quality.

Description

The present invention relates generally to technology of probing a device under test by a probe card and more particularly, to a probing method having an alignment correcting mechanism, and a probe card adapted for the probing method. 2. Description of the Related Art Nowadays, electronic components are developed with not only smaller and smaller size but also more and more complicated functions, so probe cards for testing electronic components should be developed with corresponding probing technique. For corresponding to the device under test, the probe card may be equipped with a plurality of probes for probing a plurality of electric contacts of the device under test at the same time. However, the electric contacts of the device under test may have not only quite small size themselves, but also quite small interval between their centers. Such interval between centers is also referred to as ‘pitch’ hereinafter. But probe arms of the probes have certain width probably much larger than the width of the electric contact of the device under test. Therefore, the pitch of the probes may be several times the pitch of the electric contacts of the device under test. In such condition, the probe card should perform multiple times of probing to accomplish the probing process of all the electric contacts of the device under test. For example, in the condition that the electric contacts of the device under test are arranged in a straight line, when the probe card performs every time of probing, the adjacent probes don’t probe the adjacent electric contacts. There are N electric contacts between two electric contacts probed by two adjacent probes, wherein N represents 28/10/2020 positive integer which may be one, two, three, etc. After one time of probing is performed, the probe card and the device under test are displaced relative to each other to locate the probes corresponding in position to the electric contacts that haven’t been probed, and then another time of probing is performed. Performing N+l times of probing in such manner can accomplish the probing process of all the electric contacts of the device under test.

However, the relative displacement of the probe card and the device under test usually has a little positional error, so that after the aforementioned relative displacement, probing ends of the probes will deviate from centers of the electric contacts to be probed.

The more times the aforementioned relative displacement is performed, the larger positional error the probing ends of the probes and the centers of the electric contacts to be probed by the probes usually have therebetween, which will affect the proceeding of the test and the test results.

SUMMARY OF THE INVENTION The present invention has been accomplished in view of the above-noted circumstances. It is an objective of the present invention to provide a probing method which has an alignment correcting mechanism capable of aligning a probing end of a probe with a center of an electric contact under test.

To attain the above objective, the present invention provides a probing method having an alignment correcting mechanism, which includes the steps of: aligning an image origin of an image capturing device with a target point (e.g. center) of a first electric contact of a device under test along a vertical axis, and using the image capturing device to identify that a probing end of a probe of a probe card is aligned with the target point of the first electric contact along the vertical axis; obtaining a relative position of a correction reference point of the probe card 28/10/2020 with respect to the image origin by the image capturing device in a way that the image origin is kept aligned with the target point of the first electric contact and the probing end of the probe along the vertical axis, and recording aforementioned relative position as an original reference point position; moving the probe card and the device under test relative to each other along the vertical axis to probe the first electric contact by the probe; moving the device under test in a way that the image origin is intended to be aligned with a target point (e.g. center) of a second electric contact of the device under test; obtaining a positional error between the target point of the second electric contact and the image origin by the image capturing device; and moving the probe card to make the relative position of the correction reference point with respect to the image origin a sum of the original reference point position and the positional error.

Asa result, the positional error of every time of movement of the device under test can be compensated by the movement of the probe card, so that the probing end of the probe can be aligned with the center of the electric contact to be probed before every time of probing for maintaining great testing quality. Besides, the present invention uses the movement of the device under test to intend moving the electric contact to be probed to the position corresponding to the image origin. Therefore, in every time of probing, the image capturing device needs no horizontal movement to approximately correspond in position to the electric contact under test, and the probing end of the probe is maintained adjacent to the electric contact under test, so that the image capturing device needs no horizontal movement to capture the image of the correction reference point and the probe card only needs to move for a tiny distance to compensate the positional error. In the 28/10/2020 condition that the device under test has light emitting elements, the light receiving device (e.g. integrating sphere) needs no movement to receive the light emitted by the light emitting element under test in every time of probing.

It is another objective of the present invention to provide a probe card which is 5 adapted for the above-described probing method having the alignment correcting mechanism.

To attain the above objective, the present invention provides a probe card which includes a top surface, a bottom surface, a through hole, at least one correction reference point, and at least one probe. The through hole penetrates through the top surface and the 10 bottom surface for enabling an image capturing device located above the top surface to capture an image of a device under test located below the bottom surface along a vertical axis through the through hole. The probe has a probing end for contacting the device under test. The probing end of the probe and the correction reference point are located in a way that they correspond in position to the through hole along the vertical axis.

Asa result, the probe card is adapted for being used with the image capturing device to enable the image capturing device to capture the image of the electric contact of the device under test and the probe and correction reference point of the probe card through the through hole. Besides, the position of the image origin of the image capturing device can be maintained stationarily on horizontal axes, and the image capturing device 20 can focus on the electric contact of the device under test or the correction reference point of the probe card by moving along the vertical axis only, so the probe card is adapted for being used with the above-described probing method.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the 25 detailed description and specific examples, while indicating preferred embodiments of 28/10/2020 the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: FIG. 1 is an assembled perspective view of a probe card according to a preferred embodiment of the present invention; FIG. 2 is a bottom view of the probe card according to the preferred embodiment of the present invention; FIG. 3 is a partially enlarged view of FIG. 2; FIG. 4 is a partially enlarged left view of the probe card according to the preferred embodiment of the present invention; FIG. 5 is a schematic left view of the probe card according to the preferred embodiment of the present invention, in which an image capturing device is schematically shown; FIG. 6 is a schematic view showing a part of the probe card according to the preferred embodiment of the present invention, a field of view of the image capturing 20 device, and a device under test; FIG. 7 is a partially enlarged view of FIG. 6; FIG. 8 is a flow diagram of a probing method having an alignment correcting mechanism of the present invention; and FIGS. 9-14 are schematic views of images captured by the image capturing device, showing the steps of the probing method.

DETAILED DESCRIPTION OF THE INVENTION 28/10/2020 First of all, it is to be mentioned that same or similar reference numerals used in the following embodiments and the appendix drawings designate same or similar elements or the structural features thereof throughout the specification for the purpose of 5 concise illustration of the present invention. It should be noticed that for the convenience of illustration, the components and the structure shown in the figures are not drawn according to the real scale and amount, and the features mentioned in each embodiment can be applied in the other embodiments if the application is possible in practice. Besides, when it is mentioned that an element is disposed on another element, it means that the 10 former element is directly disposed on the latter element, or the former element is indirectly disposed on the latter element through one or more other elements between aforesaid former and latter elements. When it is mentioned that an element is directly disposed on another element, it means that no other element is disposed between aforesaid former and latter elements.

Referring to FIGS. 1 and 2, a probe card 10 according to a preferred embodiment of the present invention includes a structure strengthening member 22, a main circuit board 24, a space transformer 26 and a probe head 30, which are connected from top to bottom in order. The probe card 10 is adapted to move along a vertical axis, i.e. Z-axis, to make its probes contact electric contacts of a device under test, which will be specified in the following. All the aforementioned members of the probe card 10 are approximately configured as plates arranged along horizontal axes, i.e. X-axis and Y-axis. The structures of the aforementioned members and the connections therebetween are relatively less related to the technical features of the present invention, thereby not detailedly described hereinafter. The probe card 10 of the present invention is unlimited 25 to the shape and structure provided in this embodiment, as long as it has the structural 28/10/2020 features related to the probing method described in the following.

The probe card 10 has a top surface 11, i.e. top surface of the structure strengthening member 22, a bottom surface 12, i.e. bottom surface of a circuit board 33 of the probe head 30, and a through hole 18 penetrating through the top surface 11 and the bottom surface 12. In other words, the through hole 18 penetrates through the aforementioned structure strengthening member 22, main circuit board 24, space transformer 26, and probe head 30. As shown in FIG. 3, the probe head 30 in this embodiment has sixteen probes 34A and 34B (unlimited in amount) and four alignment rods 35A and 35B (unlimited in amount), which are provided on the bottom surface of the circuit board 33, i.e. the bottom surface 12 of the probe card 10. The probes 34A and 34B are manufactured by microelectromechanical system (also referred to as MEMS). Each of the probes 34A and 34B includes a base (not shown) extending from the bottom surface 12 in the negative direction of Z-axis, a cantilever section 341 extending to a place under the through hole 18 along Y-axis from the base, and a contact section 342 extending from the terminal end of the cantilever section 341 in the negative direction of Z-axis. The contact section 342 is provided at the bottom thereof with a probing end 344, as shown in FIG. 4. Each of the alignment rods 35A and 35B includes a base (not shown) extending from the bottom surface 12 in the negative direction of Z-axis, a rod body 351 extending to a place under the through hole 18 along Y-axis from the base, and an alignment hole 352 provided at the terminal end of the rod body 351. Specifically speaking, the cantilever sections 341 of the eight probes 34A (also called first probes) and the rod bodies 351 of the two alignment rods 35 A (also called first alignment rods), which are located in the left half of FIG. 3, extend to the places under the through hole 18 in the positive direction of Y-axis (also called first direction). The cantilever sections 341 of the eight probes 34B (also called second probes) and the rod bodies 351 of the two alignment 28/10/2020 rods 35B (also called second alignment rods), which are located in the right half of FIG. 3, extend to the places under the through hole 18 in the negative direction of Y-axis (also called second direction). The probing ends 344 of the first probes 34A and the probing ends 344 of the second probes 34B are arranged in a staggered manner and aligned along 5 a straight line LI. The probing ends 344 of the probes 34A and 34B and the alignment holes 352 of the alignment rods 35 A and 35B are all located correspondingly to, i.e. aimed at, the through hole 18 along the vertical axis, i.e. Z-axis.

Referring to FIGS. 5-7, the aforementioned probe card 10 is adapted to probe a plurality of electric contacts 41, 42 and 43 of a device under test 40 by the probing ends 10 344 of the probes 34A and 34B and work in association with an image capturing device 50, e.g. charge-coupled device camera or called CCD camera, to perform a probing method having an alignment correcting mechanism provided by the present invention. The image capturing device 50 is disposed on a first displacement device (not shown) and thereby movable upwardly and downwardly along Z-axis. The probe card 10 is disposed 15 on a second displacement device (not shown) in a way that the probe card 10 is movable upwardly and downwardly along Z-axis and movable horizontally along X-axis and Yaxis. The device under test 40 is disposed on a third displacement device (not shown) in a way that the device under test 40 is movable horizontally along X-axis and Y-axis. The aforementioned first to third displacement devices may be the conventional displacement 20 device composed of motor, slide rail and moving platform, the structure of which is well known and relatively less related to the technical features of the present invention, thereby not detailedly described hereinafter.

FIG. 5 shows that the image capturing device 50 is located above the top surface 11 of the probe card 10. The lens of the image capturing device 50 is located 25 correspondingly to, i.e. aimed at, the through hole 18 located at the center of the probe 28/10/2020 card 10, thereby capable of capturing the image of the device under test 40 located below the bottom surface 12 of the probe card 10 along the vertical axis (Z-axis) through the through hole 18. FIG. 6 shows that when the image capturing device 50 captures images downwardly from a certain height toward the through hole 18, the field of view 52 of the 5 image capturing device 50 can cover the device under test 40, the part of the probes 34A and 34B located above the device under test 40, and the alignment holes 352 of the alignment rods 35 A, 35B. At this time, the electric contacts 41, 42 and 43 of the device under test 40 cannot be photographed clearly, thereby not shown in FIG. 6. The image capturing device 50 can focus downwardly on a specific electric contact and thereby 10 photograph a part of the electric contacts 41, 42 and 43 clearly. FIG. 7 is a partially enlarged view of FIG. 6 and shows a part of the electric contacts 41, 42 and 43 of the device under test 40.

The electric contacts of the device under test 40 in this embodiment include first to third electric contacts 41, 42 and 43, the pitch Pl of which equals to one third of 15 the pitch P2 of the probing ends 344 of the probes 34A and 34B. Therefore, as shown in FIG. 7, when the probing ends 344 of the probes 34A and 34B are aligned with the centers Cl of the first electric contacts 41, there are still a second electric contact 42 and a third electric contact 43 located between every two adjacent probes 34A and 34B and not aligned with the probing ends 344 of the probes 34A and 34B. In such condition, the 20 probe card 10 should perform at least three times of probing by the following probing method, i.e. the probing of the first electric contacts 41, the probing of the second electric contacts 42 and the probing of the third electric contacts 43, to accomplish the probing process of all the electric contacts 41, 42 and 43 of the device under test 40. It is to be mentioned that the purpose of the alignment correction performed in this embodiment is 25 to align the probing ends of the probes with the centers of the electric contacts for 28/10/2020 attaining the best probing effect, but the present invention is unlimited thereto. For example, a target point of the electric contact can be defined by four known corners of the electric contact for being aligned with the probing end of the probe. In other words, the centers of the electric contacts are taken as the target points of the electric contacts in 5 this embodiment, but the target points of the electric contacts are unlimited to the centers of the electric contacts.

Referring to FIGS. 8-14, the probing method having the alignment correcting mechanism provided by the present invention includes the following steps: a) As shown in FIG. 9, an image origin O of the image capturing device 50 is aligned with the center Cl of a first electric contact 41 of the device under test 40 (e.g. the leftmost first electric contact 41, which will be regarded as the aforesaid first electric contact below) along the vertical axis (Z-axis), and the image capturing device 50 is used to identify that the probing end 344 of a probe of the probe card 10 (e.g. the leftmost probe 34A, which will be regarded as the aforesaid probe below) is aligned with the center Cl of the first electric contact 41 along the vertical axis (Z-axis). This step is the step SI shown in FIG. 8.

Specifically speaking, in this step the image capturing device 50 focuses on one of the first electric contacts 41, and at the same time the image capturing device 50 is adjustable in optical setting thereof to recognize the position of the probing end 344 of the probe 34A, so that the probe card 10 can be moved by the aforementioned second displacement device to make the probing end 344 of the probe 34A aligned with the center Cl of the first electric contact 41. More specifically speaking, through the adjustment of the depth of field of the image capturing device 50, the part of the probe card 10 concealing the probing end 344 of the probe 34A and the first electric contact 41 can be located out of the scope of the depth of field of the image capturing device 50, so that the 28/10/2020 diffraction of light makes it visible to the image capturing device 50 that whether the probing end 344 of the probe 34Ais aligned with the center Cl of the first electric contact 41. In this way, the image origin O, the probing end 344 of the probe 34A and the center Cl of the first electric contact 41 are aligned in a straight line along Z-axis, so that they 5 marked by a same point in FIG. 9. In this step, the aligning action is performed to only the center Cl of a first electric contact 41 and the probing end 344 of a probe 34A, which makes the probing ends 344 of the other probes 34A and 34B also aligned with the centers Cl of the other first electric contacts 41, respectively. b) As shown in FIG. 10, in the next step the relative position (i.e. coordinates in X-Y plane) of a correction reference point R of the probe card 10 with respect to the image origin O is obtained by the image capturing device 50 in a way that the image origin O is kept aligned with the center Cl of the first electric contact 41 and the probing end 344 of the probe 34A along the vertical axis (Z-axis), and the aforementioned relative position is recorded as an original reference point position (xo,yo). This step is the step S2 shown in FIG. 8.

In this embodiment, the center of the alignment hole 352 of one of the alignment rods 35 A of the probe card 10 is taken as the correction reference point R. Because in the step a) the image capturing device 50 focuses on the center Cl of the first electric contact 41 and thereby cannot capture the image of the alignment hole 352 of the probe card 10, 20 in this step the image capturing device 50 is moved upwardly along Z-axis to the height it can capture the image of the correction reference point R. In other words, the image capturing device 50 is moved to where the field of view 52 thereof covers the alignment hole 352 of the probe card 10. The image origin O is still kept aligned with the center Cl of the first electric contact 41 and the probing end 344 of the probe 34A. Besides, the 25 correction reference point R in the present invention is unlimited to be a through hole, i.e. 28/10/2020 the aforementioned alignment hole 352. For example, the correction reference point R may be a mark having a specific shape (e.g. round dot, cross pattern, etc.) and color (e.g. black, white, etc.), a specifically shaped recess, a specifically shaped protrusion, etc. All the aforementioned configurations should be included in the implementation scope of the 5 present invention. c) Thereafter, the probe card 10 and the device under test 40 are moved relative to each other along the vertical axis (Z-axis), e.g. the probe card 10 is moved downwardly, to make the first electric contacts 41 probed by the probes 34A and 34B. This step is the step S3 shown in FIG. 8.

Because the probing ends 344 of the probes 34A and 34B are aligned with the centers Cl of the first electric contacts 41 respectively by the above-described steps, in this step the probes 34A and 34B can be used to probe the first electric contacts 41 and attains great testing quality. It is to be mentioned that the probe card 10 in this embodiment probes sixteen first electric contacts 41 by sixteen probes 34A and 34B at the same time, 15 but the probing method of the present invention is unlimited to the application of probing multiple contacts at the same time, which means the amount of the probe of the probe card 10 is unlimited. This step is unlimited to be attained by the movement of the probe card 10 along Z-axis. In fact, the probing is usually performed by moving a chuck (not shown) bearing the device under test 40 along Z-axis. However, to avoid accuracy 20 problem of the chuck, the probing is preferably performed by moving the probe card 10 along Z-axis in the present invention. d) In the next step, the device under test 40 is moved in a way that the image origin O is intended to be aligned with the center C2 of a second electric contact 42 of the device under test 40 (e.g. the leftmost second electric contact 42, which will be regarded 25 as the aforesaid second electric contact below). This step is the step S4 shown in FIG. 8. 28/10/2020 In this embodiment, because the electric contacts 41, 42 and 43 of the device under test 40 is arranged in a straight line along X-axis and the probing ends 344 of the probes 34A and 34B of the probe card is also arranged in a straight line along X-axis, this step can be performed only by using the aforementioned third displacement device to 5 move the device under test 40 along X-axis on a horizontal plane (X-Y plane) perpendicular to the Z-axis (vertical axis) after the step c) is completed and the probes 34A and 34B are disengaged from the first electric contacts 41. The word ‘intended’ mentioned in the present invention means that in this step the center C2 of the second electric contact 42 should be moved to a predetermined position, i.e. the position aligned 10 with the image origin O, but because of the accuracy limit of the third displacement device this movement will have a little error to cause that the center C2 of the second electric contact 42 will a little deviate from its predetermined position, as shown in FIG. 11. e) As shown in FIG. 11, a positional error Axi between the center C2 of the second electric contact 42 and the image origin O is obtained by the image capturing 15 device 50. This step is the step S5 shown in FIG. 8.

In other words, in this step the image capturing device 50 focuses on the second electric contact 42 to obtain the position of the center C2 of the second electric contact 42, so as to obtain the positional error Axi. At this time, the probing end 344 of the probe 34A is still aligned with the image origin O, so the centers C2 of the second electric 20 contacts 42 a little deviate from the probing ends 344 of the probes 34A and 34B respectively, and this deviation equals to the positional error Axi. f) The probe card 10 is then moved to make the relative position (coordinates in X-Y plane) of the correction reference point R with respect to the image origin O the sum of the original reference point position (xo,yo) and the positional error Axi. This step 25 is the step S6 shown in FIG. 8. 28/10/2020 In this step the image capturing device 50 is moved upwardly along Z-axis again to identify the position of the correction reference point R, and then the probe card 10 is moved by the aforementioned second displacement device according to the original reference point position (xo,yo) and the positional error Δχι to locate the correction reference point R at the position (xo+Axi,yo). It should be noticed that the positional error mentioned in the present invention is a directed value. For example, the center C2 of the second electric contact 42 shown in FIG. 11 deviates from its predetermined position in the negative direction of X-axis, which means the positional error Δχι is a negative value, so the probe card 10 is moved in the negative direction of X-axis in this step. Besides, the example taken in this embodiment is provided with positional error on X-axis only. In practice, there may be also positional error Ayi on Y-axis, and in such circumstance the correction reference point R is moved to the position (xo+Axi,yo+Ayi) in this step. Alternatively, there may be only positional error Ayi on Y-axis, but no positional error on X-axis, and in such circumstance the correction reference point R is moved to the position (xo,yo+Ayi) in this step. After this step f) is accomplished, the correction reference point R is located at a first reference point position, i.e. the aforementioned position (xo+Axi,yo), (xo,yo+Ayi) or (xo+Axi,yo+Ayi).

After this step is accomplished, as shown in FIG. 12, the probing end 344 of the probe 34Ais aligned with the center C2 of the second electric contact 42, which both deviate from the image origin O, and this deviation equals to the positional error Δχι. At the same time, the probing ends 344 of the other probes 34A and 34B are also aligned with the centers C2 of the other second electric contacts 42. Then the test process returns to the step S3 shown in FIG. 8 to probe the second electric contacts 42 by the probes 34A and 34B and attain great testing quality.

The above-described process accomplishes the probing of the first and second 28/10/2020 electric contacts 41 and 42. The probing of the third electric contacts 43 can be performed by performing the steps S4-S6 again, as the following description. As shown in FIG. 13, the device under test 40 is moved in a way that the image origin O is intended to be aligned with the center C3 of a third electric contact 43 of the device under test 40 (e.g. the leftmost third electric contact 43, which will be regarded as the aforesaid third electric contact below). Then, another positional error Ax2 between the center C3 of the third electric contact 42 and the image origin O is obtained by the image capturing device 50. Then, the probe card 10 is moved to move the correction reference point R to the position (xo+Ax2,yo) to make the probing end 344 of the probe 34A aligned with the center C3 of 10 the third electric contact 43, as shown in FIG. 14. At the same time, the probing ends 344 of the other probes 34A and 34B are also aligned with the centers C3 of the other third electric contacts 43, such that the probes 34A and 34B can probe the third electric contacts 43 and attain great testing quality. In this process, before the positional error Ax2 between the center C3 of the third electric contact 42 and the image origin O is obtained, the correction reference point R may be maintained at the aforementioned first reference point position, which means the probing end 344 of the probe 34A and the image origin O are maintained having the aforementioned positional error Δχι therebetween, as shown in FIG. 13. After the aforementioned positional error Ax2 is obtained, the probe card 10 is moved to move the correction reference point R from the first reference point position to a second reference point position, e.g. the aforementioned position (xo+Ax2,yo). Alternatively, after the second electric contacts 42 are probed by the probes 34A and 34B, the probe card 10 may be firstly moved to move the correction reference point R from the first reference point position to the original reference point position (xo,yo), which means the probing end 344 of the probe 34A is moved back to the position aligned with the image origin O. After the positional error Ax2 between the center C3 of the third electric 28/10/2020 contact 42 and the image origin O is obtained, the probe card 10 is moved to move the correction reference point R from the original reference point position (xo,yo) to the second reference point position, such correcting manner is relatively more accurate. The process described in this section takes the condition with only positional error Ax2 on X5 axis as an example. As described above, there may be positional error on Y-axis, but no positional error on X-axis. Alternatively, there may be positional error on both X-axis and Y-axis.

The above-described process accomplishes the probing of the electric contacts formerly located between the adjacent probes but not corresponding in position to the 10 probes, but it may only accomplish the probing of the electric contacts in a specific section of the device under test 40. After that, the same process can be performed to other sections haven’t been probed, so as to accomplish the probing of all electric contacts of the device under test 40. For example, the sixteen probes 34A and 34B in this embodiment performs three times of probing in the above-described process to accomplish the probing of forty15 eight electric contacts 41, 42 and 43, and then can be moved to the forty-ninth electric contact in a way that the forty-ninth electric contact is regarded as the leftmost first electric contact 41 in the above-described process, so that the same process can be performed to accomplish the probing of forty-eight other electric contacts, and so on.

It can be known from the above description that the probing method of the 20 present invention is to obtain an original reference point position (xo,yo) of the probe card 10 at first. Then, before every time of probing, the position of the probe card 10 is adjusted according to the positional error between the image origin O and the center of the electric contact to be probed, so as to compensate the positional error between the probing end 344 of the probe and the center of the electric contact to be probed, thereby maintaining 25 great testing quality. Besides, it can be known from the above-described alignment 28/10/2020 correcting process for the third electric contact 43 that in this time of correction the correction reference point R is moved to the position (xo+Ax2,yo) without any relation to the positional error Δχι in the previous time of correction. Therefore, even the displacement of the probe card 10 in the step S6 has a little error, the error will not be accumulated to the next time of probing. In other words, the probing method of the present invention can not only compensate the error of the displacement of the device under test 40, but also prevent the error of the displacement of the probe card 10 from affecting the next time of probing. In addition, the present invention uses the movement of the device under test 40 to intend moving the electric contact to be probed to the position corresponding to the image origin O. Therefore, in every time of probing, the image capturing device 50 will approximately correspond in position to the electric contact under test without the need of horizontal movement, and the probing end 344 of the probe will be maintained adjacent to the electric contact under test, so that the image capturing device 50 can capture the image of the correction reference point R without the need of horizontal movement, and the probe card 10 only needs to move for a tiny distance to compensate the positional error of the movement of the device under test 40. In the condition that the device under test 40 has light emitting elements, the light receiving device (e.g. integrating sphere) can receive the light emitted by the light emitting element under test in every time of probing without the need of movement.

As shown in FIG. 6, the probe card 10 in this embodiment has four alignment rods 35 A and 35B, each of the centers of the alignment holes 352 of which can be taken as a correction reference point R. The above-described alignment correcting process only relates to the error on X-axis and/or Y-axis, so only one of the correction reference points R is used. It is understandable that the probe card 10 of the present invention may have at least one correction reference point R. In this embodiment, the first probes 34A are 28/10/2020 located between the two first alignment rods 35A, the second probes 34B are located between the two second alignment rods 35B, and the alignment rods 35A and 35B don’t extend to the straight line LI, in which the probing ends 344 of the probes 34A and 34B are arranged. Therefore, according to the direction shown in FIG. 6, two correction reference points R are provided by the upside of the straight line LI, and two other correction reference points R are provided by the downside of the straight line LI. The straight line LI is located between the imaginary connecting line L2 of the correction reference points R of the two first alignment rods 35 A and the imaginary connecting line L3 of the correction reference points R of the two second alignment rods 35B, and no 10 connecting line of any two of the correction reference points R coincides with the straight line LI. Besides, the probing ends 344 of the probes 34A and 34B are all located within an area 36 defined by the correction reference points R. A plurality of correction reference points R enable the correction of multi-axial error, and the above-described arrangement of the correction reference points R and the probes 34A and 34B provided in this 15 embodiment even enables the correction of an angular error between the direction of the arrangement of the probes and the direction of the arrangement of the electric contacts to be tested.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the scope 20 of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims (18)

1. A probing method having an alignment correcting mechanism, the probing method comprising the steps of: a) aligning an image origin of an image capturing device with a target point of 5 a first electric contact of a device under test along a vertical axis, and using the image capturing device to identify that a probing end of a probe of a probe card is aligned with the target point of the first electric contact along the vertical axis; b) obtaining a relative position of a correction reference point of the probe card with respect to the image origin by the image capturing device in a way that the image 10 origin is kept aligned with the target point of the first electric contact and the probing end of the probe along the vertical axis, and recording said relative position as an original reference point position; c) moving the probe card and the device under test relative to each other along the vertical axis to probe the first electric contact by the probe; 15 d) moving the device under test in a way that the image origin is intended to be aligned with a target point of a second electric contact of the device under test; e) obtaining a positional error between the target point of the second electric contact and the image origin by the image capturing device; and f) moving the probe card to make the relative position of the correction 20 reference point with respect to the image origin a sum of the original reference point position and the positional error.

2. The probing method as claimed in claim 1, wherein in the step a), the image capturing device is disposed above the probe card. 28/10/2020

3. The probing method as claimed in claim 2, wherein in the step b), the image capturing device is moved upwardly along the vertical axis to where a field of view of the image capturing device covers an alignment hole of the probe card, and a center of the alignment hole is taken as the correction reference point of the probe card.

4. The probing method as claimed in claim 3, wherein the probe card comprises a through hole, said probe and an alignment rod; the probe and the alignment rod extend under the through hole, and the alignment rod has said alignment hole. 10

5. The probing method as claimed in claim 1, wherein in the step d), the device under test is moved along a horizontal axis perpendicular to the vertical axis.

6. The probing method as claimed in claim 5, wherein in the step e), the positional error comprises one of: 15 a positional error between the target point of the second electric contact and the image origin on the horizontal axis; a positional error between the target point of the second electric contact and the image origin on another horizontal axis perpendicular to the vertical axis and perpendicular to said horizontal axis; and 20 a positional error between the target point of the second electric contact and the image origin on said horizontal axis and on said another horizontal axis.

7. The probing method as claimed in claim 1, wherein after the step f), the correction reference point is located at a first reference point position; then, the probe 25 card and the device under test are moved relative to each other along the vertical axis to 28/10/2020 make the second electric contact probed by the probe; then, the device under test is moved in a way that the image origin is intended to be aligned with a target point of a third electric contact of the device under test; then, another positional error between the target point of the third electric contact and the image origin is obtained by the image capturing 5 device; then, the probe card is moved to move the correction reference point from the first reference point position to a second reference point position, wherein the second reference point position is a sum of the original reference point position and said another positional error; then, the probe card and the device under test are moved relative to each other along the vertical axis to make the third electric contact probed by the probe.

8. The probing method as claimed in claim 1, wherein after the step f), the correction reference point is located at a first reference point position; then, the probe card and the device under test are moved relative to each other along the vertical axis to make the second electric contact probed by the probe; then, the device under test is moved 15 in a way that the image origin is intended to be aligned with a target point of a third electric contact of the device under test; then, another positional error between the target point of the third electric contact and the image origin is obtained by the image capturing device; then, the probe card is moved to make the relative position of the correction reference point with respect to the image origin a sum of the original reference point 20 position and said another positional error, so that the correction reference point is located at a second reference point position; then, the probe card and the device under test are moved relative to each other along the vertical axis to make the third electric contact probed by the probe; in a process after the second electric contact is probed by the probe and before the third electric contact is probed by the probe, the correction reference point 25 of the probe card is firstly moved from the first reference point position to the original 28/10/2020 reference point position and then moved from the original reference point position to the second reference point position.

9. A probe card comprising a top surface, a bottom surface, a through hole, at 5 least one correction reference point, and at least one probe, the through hole penetrating through the top surface and the bottom surface for enabling an image capturing device located above the top surface to capture an image of a device under test located below the bottom surface along a vertical axis through the through hole, the probe having a probing end for contacting the device under test, the probing end of the probe and the correction 10 reference point being located corresponding in position to the through hole along the vertical axis.

10. The probe card as claimed in claim 9, wherein the probe card further comprises at least one alignment rod; the alignment rod is fixed on the bottom surface 15 and extends under the through hole; the alignment rod has an alignment hole; the correction reference point is located at a center of the alignment hole.

11. The probe card as claimed in claim 9, wherein the probe card comprises a plurality of said correction reference points and a plurality of said probes.

12. The probe card as claimed in claim 11, wherein the probing ends of the probes are arranged in a straight line; no connecting line of any two of the correction reference points coincides with the straight line. 25

13. The probe card as claimed in claim 12, wherein each of two sides of the straight line is provided with at least one of said correction reference points. 28/10/2020

14. The probe card as claimed in claim 13, wherein each of the two sides of the straight line is provided with two of said correction reference points, and the probing ends 5 of the probes are all located within an area defined by the correction reference points.

15. The probe card as claimed in claim 11, wherein the probe card further comprises a plurality of alignment rods; each of the alignment rods is fixed on the bottom surface and extends under the through hole; each of the alignment rods has an alignment 10 hole; the correction reference points are located at centers of the alignment holes, respectively.

16. The probe card as claimed in claim 15, wherein the probes comprise a plurality of first probes fixed on the bottom surface and extending under the through hole 15 in a first direction, and a plurality of second probes fixed on the bottom surface and extending under the through hole in a second direction opposite to the first direction; the probing ends of the first probes and the probing ends of the second probes are arranged in a staggered manner and arranged in a straight line; no connecting line of any two of the correction reference points coincides with the straight line.

17. The probe card as claimed in claim 16, wherein the alignment rods comprise two first alignment rods and two second alignment rods; the first probes are located between the two first alignment rods; the second probes are located between the two second alignment rods; the straight line, in which the probing ends of the probes are 25 arranged, is located between a connecting line of the correction reference points of the two first alignment rods and another connecting line of the correction reference points of the two second alignment rods. 28/10/2020

18. The probe card as claimed in claim 9, wherein the probe card further 5 comprises at least one alignment rod; the alignment rod is fixed on the bottom surface and extends under the through hole; the alignment rod has one of an alignment hole, a mark, a recess and a protrusion to serve as the correction reference point.