Inspection system and inspection method

Abstract

To provide an inspection system and inspection method capable of reducing a time and cost required to determine parallelism of an inspected body.SOLUTION: An inspection system includes: an inspection tool having a plurality of probes arranged to allow respective distal ends to face an inspected body; a measurement device for measuring an electric parameter to be changed depending on an interval between the inspected body and the distal end for each probe; a detection device for detecting a variation of the electric parameter due to a change of the interval for each probe with the use of measurement values of the electric parameters respectively measured at the plurality of intervals; and a determination device for determining whether the inspected body is arranged in parallel with the inspection tool based on the variation of the electric parameters.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inspection system and an inspection method used for checking the parallelism of an object to be inspected. [Background technology]

[0002] In some cases, it is necessary to check the parallelism of an object undergoing characteristic inspection or processing. Here, "parallelism" refers to the degree to which the object is parallel to the inspection or processing device. Inspection devices with probes that contact the object are used to inspect the characteristics of objects such as printed circuit boards or semiconductor devices formed on wafers. To accurately inspect an object while simultaneously contacting multiple probes with the object, each probe must contact the object with equal pressure. Therefore, it is important that the inspection jig holding the probes of the inspection device and the object are positioned parallel to each other. Furthermore, when processing the object, such as grinding or polishing, the object must be positioned parallel to the processing device. Hereinafter, an object requiring a parallelism inspection will also be referred to as the "inspected object." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-175572 Summary of the Invention [Problem to be solved by the invention]

[0004] To determine the parallelism of the object under test, for example, there is a method of measuring the distance between the tip of each probe and the object under test, in which the inspection jig and the object under test are made parallel by adjusting the arrangement of the inspection jig or the object under test so that the distance between the tip of each probe and the object under test is equal.

[0005] However, measuring the distance between the tip of each probe and the object under test takes time and requires a measuring device, which makes determining the parallelism between the inspection jig and the object under test time-consuming and costly.

[0006] An object of the present invention is to provide an inspection system and an inspection method that can reduce the time and cost required to determine the parallelism of an object under inspection. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided an inspection system including an inspection jig having multiple probes, a measurement device that measures electrical parameters, a detection device that detects changes in the electrical parameters, and a determination device that determines whether the object under test and the inspection jig are arranged parallel to each other. The inspection jig has multiple probes arranged so that their tips face the object under test. The measurement device measures, for each probe, an electrical parameter that changes depending on the distance between the object under test and its tip. The detection device uses the measured values ​​of the electrical parameters measured at each of the multiple distances to detect, for each probe, the amount of change in the electrical parameter caused by the change in distance. The determination device determines whether the object under test and the inspection jig are arranged parallel to each other based on the amount of change in the electrical parameter. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an inspection system and an inspection method that can reduce the time and cost required to determine the parallelism of an object under inspection. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an inspection system according to the first embodiment. [Figure 2] FIG. 2 is a flowchart illustrating the inspection method according to the first embodiment. [Figure 3] FIG. 3 is a flowchart showing an example of a method for setting the first facing distance. [Figure 4] FIG. 4 is a schematic diagram showing the configuration of an inspection system according to a modified example of the first embodiment. [Figure 5] FIG. 5 is a schematic diagram showing the configuration of a parallelism determination system of a comparative example. [Figure 6] FIG. 6 is a schematic diagram for explaining an inspection method using the inspection system according to the second embodiment. [Figure 7] FIG. 7 is a flowchart showing an example of a method for setting the second facing distance. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, identical or similar parts are designated by identical or similar reference numerals. However, it should be noted that the drawings are schematic, and the thickness ratios of the various parts may differ from those in reality. Furthermore, it goes without saying that the dimensional relationships and ratios of parts included in the drawings may differ from one another. The embodiments shown below exemplify devices and methods for embodying the technical ideas of the present invention, and the materials, shapes, structures, arrangements, etc. of the components of the embodiments of the present invention are not limited to those described below.

[0011] (First embodiment) An inspection system 1 according to a first embodiment of the present invention shown in FIG. 1 is used to inspect the parallelism of an object under test 2. After the parallelism of the object under test 2 has been confirmed, the inspection system 1 may be used to inspect the characteristics of the object under test 2. The object under test 2 has a first terminal 211 to a third terminal 213 arranged on a first surface 201. Hereinafter, the first terminals 211 to the third terminals 213 will be referred to as terminals 21 unless otherwise specified. The object under test 2 is, for example, a printed circuit board in which wiring patterns are connected to the multiple terminals 21, respectively. When the object under test 2 is a printed circuit board, the inspection system 1 is used to inspect the characteristics, for example, the presence or absence of short circuits or breaks in the wiring patterns of the printed circuit board.

[0012] The inspection system 1 includes an inspection jig 11 , a switch 12 , a measuring device 13 , a detecting device 14 , and a determining device 15 .

[0013] The inspection jig 11 has first probes 101 to third probes 103 whose tips face the device under test 2. The first probes 101 to 103 are arranged so that their tips face the first terminals 211 to 213 of the device under test 2. Hereinafter, the first probes 101 to 103 will be referred to as probes 10 unless otherwise specified. The inspection jig 11 is arranged facing the device under test 2. Hereinafter, a pair of a terminal 21 and a probe 10 that face each other will also be referred to as a "facing pair."

[0014] 1, the direction in which the inspection jig 11 is placed relative to the object under inspection 2 is defined as the Z direction. In FIG. 1, the Z direction is the vertical direction of the paper, the X direction is the horizontal direction of the paper, and the Y direction is the depth direction of the paper.

[0015] 1 shows an example in which the number of probes 10 held by the inspection jig 11 is three, but the number of probes 10 is not limited to three. A plurality of probes 10 are arranged on the inspection jig 11 so as to face a plurality of regions spaced apart from one another on the first surface 201 of the object under test 2. While FIG. 1 shows an example in which the probes 10 are arranged along the X direction, the probes 10 may also be arranged along the Y direction, or the probes 10 may be arranged in a matrix on an XY plane perpendicular to the Z direction.

[0016] The switch 12 selectively electrically connects the multiple probes 10 held by the inspection jig 11 to the measuring device 13. The switch 12 can electrically connect two or more probes 10 to the measuring device 13 at the same time.

[0017] For each probe 10, the measuring device 13 measures an electrical parameter that varies depending on the distance between the terminal 21 and the tip of the probe 10 (hereinafter referred to as the "facing distance D"). The facing distance D is the distance along the Z direction. The measured values ​​of the electrical parameters measured by the measuring device 13 are stored in the measurement value storage device 16. When the switch 12 electrically connects multiple probes 10 to the measuring device 13 at the same time, the measuring device 13 measures the electrical parameters for multiple probes 10 at the same time.

[0018] The detection device 14 uses the measured values ​​of the electrical parameters measured by the measurement device 13 at multiple facing distances D for each probe 10 to detect the amount of change in the electrical parameters caused by changes in the facing distance D for each probe 10. For example, the detection device 14 may detect the amount of change in the electrical parameters as a difference between the measured values ​​of the electrical parameters measured at each of the different facing distances D.

[0019] The detection device 14 reads out the measured values ​​of the electrical parameters stored in the measurement value storage device 16 and detects the amount of change in the electrical parameters for each probe 10. Alternatively, the detection device 14 may obtain the measured values ​​of the electrical parameters measured by the measurement device 13 directly from the measurement device 13.

[0020] The determination device 15 determines whether the object under test 2 and the inspection jig 11 are arranged parallel to each other, based on the amount of change in the electrical parameter detected by the detection device 14. Hereinafter, the determination of whether the object under test 2 and the inspection jig 11 are arranged parallel to each other is also referred to as "determination of parallelism." The method of determining parallelism by the determination device 15 will be described in detail later.

[0021] The determination result display device 17 displays the result of the parallelism determination made by the determination device 15. The determination result display device 17 may be, for example, an image display device such as a display.

[0022] The inspection system 1 includes a gap adjustment device 18 that adjusts the gap between the object under inspection 2 and the inspection jig 11 to change the facing distance D. The inspection system 1 shown in FIG. 1 includes, as the gap adjustment device 18, an inspection stage 181 on which the object under inspection 2 is placed, and a stage driving device 182 that controls the inspection stage 181. For example, the stage driving device 182 moves the inspection stage 181 in the Z direction.

[0023] The inspection system 1 shown in FIG. 1 uses the capacitance between the device under test 2 and the tip of the probe 10 as an electrical parameter for determining parallelism. As shown in FIG. 1, the capacitance between the tip of the first probe 101 and the first terminal 211 is referred to as a first variable capacitance C11. The capacitance between the tip of the second probe 102 and the second terminal 212 is referred to as a second variable capacitance C12. The capacitance between the tip of the third probe 103 and the third terminal 213 is referred to as a third variable capacitance C13. Hereinafter, when each of the first variable capacitance C11 to the third variable capacitance C13 is not limited, the capacitance between the tip of the probe 10 and the terminal 21 is referred to as a variable capacitance C1. The variable capacitance C1 changes due to a change in the facing distance D.

[0024] The device under test 2 has a conductive parallel plate 23. The parallel plate 23 is capacitively coupled to the terminal 21. In the device under test 2 shown in FIG. 1, the parallel plate 23 is disposed on the second surface 202 opposite the first surface 201. The capacitances between the first terminal 211 to the third terminal 213 and the parallel plate 23 are referred to as first fixed capacitance C21 to third fixed capacitance C23. Hereinafter, when the first fixed capacitance C21 to third fixed capacitance C23 are not limited, the capacitance between the terminal 21 and the parallel plate 23 is referred to as fixed capacitance C2. For example, the fixed capacitance C2 is an internal capacitance of the device under test 2. The fixed capacitance C2 does not change even if the facing distance D changes.

[0025] A reference terminal 22 electrically connected to the parallel plate 23 is disposed on the first surface 201 of the device under test 2. For example, the reference terminal 22 and the parallel plate 23 are electrically connected by an internal wiring 24 that passes through the device under test 2 from the first surface 201 to the second surface 202.

[0026] The inspection system 1 includes a measurement terminal 121 that can be electrically connected to the reference terminal 22 when measuring an electrical parameter. The measurement device 13 measures the electrical parameter between the probe 10 and the measurement terminal 121. That is, the measurement device 13 shown in FIG. 1 measures a capacitance that is a combination of a variable capacitance C1 and a fixed capacitance C2.

[0027] With the first probe 101 connected to the measurement device 13, the measurement device 13 measures a first total capacitance C31 for an electrical path including the opposing pair of the first probe 101 and the first terminal 211. Here, the first total capacitance C31 is a total capacitance obtained by connecting the first variable capacitance C11 and the first fixed capacitance C21 in series. Furthermore, with the second probe 102 connected to the measurement device 13, the measurement device 13 measures a second total capacitance C32 for an electrical path including the opposing pair of the second probe 102 and the second terminal 212. The second total capacitance C32 is a total capacitance obtained by connecting the second variable capacitance C12 and the second fixed capacitance C22 in series. Furthermore, with the third probe 103 connected to the measurement device 13, the measurement device 13 measures a third total capacitance C33 for an electrical path including the opposing pair of the third probe 103 and the third terminal 213. The third combined capacitance C33 is a combined capacitance obtained by connecting the third variable capacitance C13 and the third fixed capacitance C23 in series. Hereinafter, when the first combined capacitance C31 to the third combined capacitance C33 are not limited to any particular capacitance, the combined capacitance of the variable capacitance C1 and the fixed capacitance C2 will be referred to as combined capacitance C3.

[0028] The inspection system 1 sequentially measures the composite capacitance C3 for each probe 10 while switching the probe 10 connected to the measurement device 13 using the switch 12. Alternatively, the switch 12 may electrically connect multiple probes 10 to the measurement device 13 at the same time, and the measurement device 13 may measure electrical parameters for the multiple probes 10 at the same time. For example, the inspection system 1 may simultaneously measure the first composite capacitance C31, the second composite capacitance C32, and the third composite capacitance C33. By simultaneously measuring the electrical parameters for the multiple probes 10, the time required to determine the parallelism can be shortened.

[0029] Measurements for determining the parallelism between the inspection jig 11 and the test object 2 are performed by changing the facing distance D while the measurement terminal 121 and the reference terminal 22 are electrically connected. For example, by using a flexible measurement terminal 121, the facing distance D can be changed while the measurement terminal 121 and the reference terminal 22 remain electrically connected. Alternatively, a configuration that is flexible in the Z direction may be adopted for the measurement terminal 121, and the facing distance D may be changed while the measurement terminal 121 and the reference terminal 22 remain electrically connected. For example, a probe having a spring portion that is flexible in the Z direction may be used as the measurement terminal 121 that is flexible in the Z direction. Furthermore, the measurement terminal 121 and the measurement device 13 may be connected by a connecting member such as a flexible conductive wire.

[0030] An example of a method for determining the parallelism between the inspection jig 11 and the object under inspection 2 using the inspection system 1 shown in FIG. 1 will be described below with reference to FIG.

[0031] In step S10 of FIG. 2, with the measuring terminal 121 and the reference terminal 22 electrically connected, the gap adjusting device 18 sets the gap between the device under test 2 and the inspection jig 11 to a first facing distance D1.

[0032] Next, in step S20, the measurement device 13 measures, as an electrical parameter, the resultant capacitance C3 at the first facing distance D1 for each probe 10. The measured resultant capacitance C3 is stored in the measurement value storage device 16 in association with the first facing distance D1 for each probe 10.

[0033] Next, in step S30, the gap adjusting device 18 sets the gap between the object under test 2 and the inspection jig 11 to a second facing distance D2 different from the first facing distance D1. For example, the second facing distance D2 is set shorter than the first facing distance D1.

[0034] Next, in step S40, the measurement device 13 measures, as an electrical parameter, the resultant capacitance C3 at the second facing distance D2 for each probe 10. The measured resultant capacitance C3 is stored in the measurement value storage device 16 in association with the second facing distance D2 for each probe 10.

[0035] In step S50, the detection device 14 detects, for each probe 10, a change in the electrical parameter caused by a change in the facing distance D, using the measured values ​​of the electrical parameter measured at the first facing distance D1 and the second facing distance D2. That is, the detection device 14 detects, for each probe 10, a change in the composite capacitance C3 caused by a change in the facing distance D, using the composite capacitance C3 measured at the first facing distance D1 and the composite capacitance C3 measured at the second facing distance D2. For example, the detection device 14 reads out from the measurement value storage device 16 the composite capacitance C3 measured at the first facing distance D1 (hereinafter referred to as the "first measured capacitance C3A") and the composite capacitance C3 measured at the second facing distance D2 (hereinafter referred to as the "second measured capacitance C3B"). The detection device 14 then detects the difference between the first measured capacitance C3A and the second measured capacitance C3B as the amount of change in the combined capacitance C3 caused by the change in the facing distance D (hereinafter also referred to as the "differential capacitance Cd"). For example, when the second facing distance D2 is shorter than the first facing distance D1, the value obtained by subtracting the first measured capacitance C3A from the second measured capacitance C3B is the differential capacitance Cd. The detected differential capacitance Cd is transmitted to the determination device 15.

[0036] In step S60, the determination device 15 determines whether the device under test 2 and the inspection jig 11 are arranged in parallel based on the differential capacitance Cd, which is the amount of change in the electrical parameter. For example, the determination device 15 determines whether the differential capacitance Cd for each probe 10 is within a predetermined range of determination values. The determination device 15 determines that the device under test 2 and the inspection jig 11 are arranged in parallel when the differential capacitance Cd for all of the probes 10 is within the range of determination values. On the other hand, if there is even one probe 10 whose differential capacitance Cd is not within the range of determination values, the determination device 15 determines that the device under test 2 and the inspection jig 11 are not arranged in parallel.

[0037] The judgment result by the judgment device 15 is transmitted to the judgment result display device 17. The user of the inspection system 1 may refer to the judgment result displayed by the judgment result display device 17 to determine whether or not to perform a characteristic inspection of the object under test 2. That is, if the judgment result indicates that the object under test 2 and the inspection jig 11 are arranged parallel to each other, the characteristic inspection of the object under test 2 using the inspection system 1 is performed. On the other hand, if the judgment result indicates that the object under test 2 and the inspection jig 11 are not arranged parallel to each other, the user of the inspection system 1 adjusts the arrangement of either or both of the object under test 2 and the inspection jig 11 so that the object under test 2 and the inspection jig 11 are parallel to each other. For example, the angle formed by the object under test 2 or the inspection stage 181 with respect to the XY plane is adjusted. Alternatively, the angle formed by the inspection jig 11 with respect to the XY plane is adjusted.

[0038] The judgment value used by the judgment device 15 to judge the parallelism between the object under test 2 and the inspection jig 11 can be set arbitrarily depending on the accuracy of parallelism required for the inspection content of the object under test 2. In other words, the judgment value is set so that the parallelism between the object under test 2 and the inspection jig 11 can be obtained within a range that does not affect the inspection of the object under test 2. The judgment value may be input to the judgment device 15 via an input device (not shown) of the inspection system 1, for example.

[0039] The first facing distance D1 and the second facing distance D2 are set to distances that allow measurement of the variable capacitance C1. For example, the first facing distance D1 and the second facing distance D2 are set so that the variable capacitance C1 falls within a distance range that is a valid measurement value with guaranteed measurement accuracy through simulation or prior test measurements. In addition, the difference between the first facing distance D1 and the second facing distance D2 is set so that a certain difference occurs between the first measurement capacitance C3A and the second measurement capacitance C3B.

[0040] When the facing distance D is sufficiently long, the variable capacitance C1 is zero. The variable capacitance C1 increases when the facing distance D is shortened. Therefore, the multiple facing distances D at which the measurement device 13 measures the composite capacitance C3 may include a first facing distance D1 at which the first measurement capacitance C3A is zero and a second facing distance D2 that is shorter than the first facing distance D1.

[0041] The first facing distance D1 may be set, for example, as shown in Fig. 3. First, in step S11, the gap adjustment device 18 sets the gap between the device under test 2 and the inspection jig 11 to an arbitrary initial distance. Next, in step S12, the measurement device 13 measures the capacitance between any one of the multiple probes 10 and the reference terminal 22. For example, the measurement device 13 measures the capacitance between the first probe 101 and the reference terminal 22. Hereinafter, the capacitance value measured in step S12 will also be referred to as the "setting capacitance value."

[0042] In step S13, the measuring device 13 compares the setting capacitance value with a predetermined capacitance threshold value. If the setting capacitance value is greater than the capacitance threshold value, the process proceeds to step S14, where the distance between the device under test 2 and the inspection jig 11 at that time is set to the first facing distance D1. On the other hand, if the setting capacitance value does not exceed the capacitance threshold value in step S13, the process proceeds to step S15, where the distance between the device under test 2 and the inspection jig 11 is narrowed. After step S15, the process returns to step S12.

[0043] The capacitance threshold is an electric capacitance value that serves as a guide for bringing the object under test 2 and the inspection jig 11 closer together. The capacitance threshold is set to a valid measurement value with guaranteed measurement accuracy. The initial distance may be, for example, the maximum distance at which a valid measurement value can be obtained by the measurement device 13.

[0044] Although the above describes an example in which one probe 10 faces one terminal 21, multiple probes 10 may face one terminal 21. For example, the first terminal 211 and the second terminal 212 of the device under test 2 may be connected. Furthermore, when the device under test 2 has one terminal 21 extending over the first surface 201, the inspection system 1 can determine the parallelism of the device under test 2 by arranging multiple probes 10 facing the terminal 21 at a distance from each other.

[0045] It is not necessary that the probes 10 face all of the terminals 21 of the device under test 2. In other words, it is sufficient that a plurality of probes 10 are arranged facing the first surface 201 of the device under test 2, and the distance between the probes 10 is within a range that allows the parallelism of the device under test 2 to be determined.

[0046] Furthermore, although the above description concerns a device under test 2 having a parallel plate 23 that is capacitively coupled to the terminal 21, the device under test 2 does not have to have a parallel plate 23. In a device under test 2 that does not have a parallel plate 23, the terminal 21 and the reference terminal 22 are capacitively coupled due to, for example, the internal capacitance of the device under test 2, and the test system 1 measures the combined capacitance C3. Furthermore, the device under test 2 does not have to have either the terminal 21 or the parallel plate 23. The region of the first surface 201 facing the tip of the probe 10 and the reference terminal 22 are capacitively coupled due to the internal capacitance of the device under test 2, and the test system 1 measures the combined capacitance C3.

[0047] In the above, the method of determining the parallelism between the object under test 2 and the inspection jig 11 by comparing the differential capacitance Cd of each opposing pair with a determination value has been described. However, the parallelism between the object under test 2 and the inspection jig 11 may be determined by other methods using the differential capacitance Cd.

[0048] For example, if the difference between the maximum and minimum values ​​of the differential capacitance Cd detected for each probe 10 is within a predetermined range of judgment values, it may be determined that the device under test 2 and the inspection jig 11 are arranged in parallel.

[0049] Alternatively, one of the probes 10 may be selected as a reference probe, and the parallelism of the DUT 2 may be determined using the measurement value of the reference probe. That is, the inspection system 1 may determine that the DUT 2 and the inspection jig 11 are arranged parallel to each other if the difference between the differential capacitance Cd of all the probes 10 excluding the reference probe and the differential capacitance Cd of the reference probe is within a predetermined determination value range. This reference probe may be selected using the measurement value of the composite capacitance C3. For example, the probe 10 whose measured composite capacitance C3 is closest to the average value of the composite capacitances C3 measured for all the probes 10 may be selected as the reference probe. In this case, the reference probe may be selected during the measurement of the composite capacitance to determine the parallelism of the inspection jig 11 and the DUT 2.

[0050] <Modification> In the inspection system 1 shown in FIG. 1, most of the second surface 202 of the device under test 2 is separated from the inspection stage 181. On the other hand, in the inspection system 1 shown in FIG. 4, the inspection stage 181 contacts the entire surface of the second surface 202 of the device under test 2. Because the inspection stage 181 is conductive, the terminal 21 of the device under test 2 and the reference terminal 22 can be electrically connected even if the device under test 2 does not have a parallel plate 23. In other words, as long as the second surface 202 of the device under test 2 is in contact with the conductive inspection stage 181, the inspection system 1 can measure the combined capacitance C3 even if the device under test 2 does not have a parallel plate 23.

[0051] For comparison with the determination of parallelism by the inspection system 1, a method for determining the parallelism between the inspection jig 11 and the object under inspection 2 by a parallelism determination system 1M of a comparative example shown in Fig. 5 will be described below. The parallelism determination system 1M includes a displacement measuring device 51 and a displacement determination device 52.

[0052] The displacement measuring device 51 is disposed between the inspection jig 11 and the object under inspection 2. The displacement measuring device 51 has a first laser displacement meter 511 disposed opposite the inspection jig 11 and a second laser displacement meter 512 disposed opposite the object under inspection 2. Under the control of a displacement meter driving device 513, the first laser displacement meter 511 and the second laser displacement meter 512 move along the XY plane.

[0053] 5, in order to measure the distance from the displacement measuring device 51 to the tip of the first probe 101, the displacement meter driving device 513 moves the first laser displacement meter 511 to a position directly below the first probe 101. The first laser displacement meter 511 then receives the reflected light from the first probe 101 of the first laser beam L1 projected onto the first probe 101, and measures the distance from the displacement measuring device 51 to the first probe 101. Furthermore, while the displacement meter driving device 513 changes the position of the first laser displacement meter 511, the first laser displacement meter 511 measures the distance from the displacement measuring device 51 to the second probe 102 and the distance from the displacement measuring device 51 to the third probe 103.

[0054] The distance from the displacement measuring device 51 to the probe 10 is transmitted to the displacement determination device 52. The displacement determination device 52 uses the distance from the displacement measuring device 51 to each probe 10 to determine whether the parallelism between the inspection jig 11 and the displacement measuring device 51 is within a predetermined tolerance range. For example, the displacement determination device 52 determines that the parallelism between the inspection jig 11 and the displacement measuring device 51 is within the tolerance range when all differences in the distances from the displacement measuring device 51 to the probes 10 are smaller than a parallelism threshold value. The parallelism threshold value may be input to the displacement determination device 52 from an input device 521. The determination result by the displacement determination device 52 is displayed on a determination display device 522.

[0055] 5, in order to measure the distance from the displacement measuring device 51 to the first terminal 211, the displacement meter driving device 513 moves the second laser displacement meter 512 to a position directly above the first terminal 211. The second laser displacement meter 512 receives the reflected light from the first terminal 211 of the second laser beam L2 projected onto the first terminal 211, and measures the distance from the displacement measuring device 51 to the first terminal 211. Furthermore, while the displacement meter driving device 513 changes the position of the second laser displacement meter 512, the second laser displacement meter 512 measures the distance from the displacement measuring device 51 to the second terminal 212 and the distance from the displacement measuring device 51 to the third terminal 213.

[0056] The distances from the displacement measuring device 51 to the terminals 21 are transmitted to the displacement determining device 52. The displacement determining device 52 uses the distances from the displacement measuring device 51 to each terminal 21 to determine whether the parallelism between the object under test 2 and the displacement measuring device 51 is within a predetermined tolerance range. For example, if all differences in the distances from the displacement measuring device 51 to the terminals 21 are smaller than the parallelism threshold value, the displacement determining device 52 determines that the parallelism between the object under test 2 and the displacement measuring device 51 is within the tolerance range. The determination result by the displacement determining device 52 is displayed on the determination display device 522.

[0057] As described above, the parallelism determination system 1M measures the distance from the displacement measuring device 51 to the probe 10 and determines the parallelism between the inspection jig 11 and the displacement measuring device 51. Furthermore, the parallelism determination system 1M measures the distance from the displacement measuring device 51 to the terminal 21 and determines the parallelism between the object under test 2 and the displacement measuring device 51. The parallelism determination system 1M determines the parallelism between the inspection jig 11 and the displacement measuring device 51, and the parallelism between the object under test 2 and the displacement measuring device 51, thereby indirectly determining the parallelism between the inspection jig 11 and the object under test 2.

[0058] The parallelism determination system 1M moves the first laser displacement meter 511 a number of times equal to the number of probes 10, and measures the distance from the displacement measuring device 51 to the probe 10 for each probe 10. Then, the parallelism determination system 1M moves the second laser displacement meter 512 a number of times equal to the number of terminals 21, and measures the distance from the displacement measuring device 51 to the terminal 21 for each terminal 21. Therefore, it is necessary to align the probe 10 with the first laser displacement meter 511 a number of times equal to the number of probes 10, and to align the terminal 21 with the second laser displacement meter 512 a number of times equal to the number of terminals 21.

[0059] For this reason, the method of determining the parallelism between the inspection jig 11 and the object under test 2 using the parallelism determination system 1M requires a long time to determine the parallelism. In particular, the greater the number of probes 10 and the number of terminals 21, the longer the time required for the parallelism determination system 1M to determine the parallelism. For example, assuming that the measurement time using a laser displacement meter is one second per location, if there are 10,000 probes 10 and 10,000 terminals 21, it takes approximately 333 minutes just to measure the distance. Thus, the method of determining the parallelism between the inspection jig 11 and the object under test 2 using the parallelism determination system 1M has low productivity.

[0060] On the other hand, when the parallelism between the inspection jig 11 and the object under test 2 is determined using the inspection system 1, the measuring device 13 measures the electrical parameters for each probe 10 while all of the probes 10 and terminals 21 are aligned. Therefore, the method using the inspection system 1 can reduce the time required to determine the parallelism compared to the method using the parallelism determination system 1M. Furthermore, since a measuring device such as a laser displacement meter for measuring distance is not required, the cost for determining the parallelism between the inspection jig 11 and the object under test 2 can be reduced.

[0061] As described above, in the inspection system 1 according to the first embodiment, the amount of change in capacitance is measured for the probe 10 as the amount of change in the electrical parameter caused by a change in the facing distance D. Then, based on the amount of change in capacitance measured for the probe 10, the parallelism between the inspection jig 11 and the device under test 2 is determined. Therefore, the inspection system 1 can reduce the time and cost required to determine the parallelism between the inspection jig 11 and the device under test 2.

[0062] (Second embodiment) The inspection system 1 according to the second embodiment differs from the inspection system 1 according to the first embodiment, in which the electrical parameter measured for the probe 10 is electrical resistance, in that the electrical parameter measured for the probe 10 is electrical capacitance. Fig. 6 is a schematic diagram illustrating an inspection method using the inspection system 1 when the electrical parameter used to determine the parallelism between the inspection jig 11 and the object under test 2 is electrical resistance. The inspection system 1 shown in Fig. 6 includes the inspection jig 11, a measuring device 13, a detecting device 14, a determining device 15, and a gap adjusting device 18, similar to the inspection system 1 shown in Fig. 1.

[0063] 6, the electrical resistance between the tip of the first probe 101 and the first terminal 211 is referred to as a first variable electrical resistance R11. The electrical resistance between the tip of the second probe 102 and the second terminal 212 is referred to as a second variable electrical resistance R12. The electrical resistance between the tip of the third probe 103 and the third terminal 213 is referred to as a third variable electrical resistance R13. Hereinafter, when the first variable electrical resistance R11 to the third variable electrical resistance R13 are not limited, the electrical resistance between the tip of the probe 10 and the terminal 21 is referred to as a variable electrical resistance R1.

[0064] For ease of explanation, FIG. 6 illustrates the variable electrical resistance R1 when the tip of the probe 10 and the terminal 21 are separated. The variable electrical resistance R1 changes due to changes in the facing distance D. That is, when the facing distance D is sufficiently long, the variable electrical resistance R1 is almost infinite. On the other hand, when the tip of the probe 10 and the terminal 21 are in contact, the variable electrical resistance R1 is almost zero. In this way, the variable electrical resistance R1 changes when the facing distance D is changed.

[0065] The device under test 2 has a conductive plate 25 electrically connected to the terminal 21. In the device under test 2 shown in FIG. 6, the conductive plate 25 is arranged on the first surface 201 on which the terminal 21 is arranged. Furthermore, a reference terminal 22 electrically connected to the conductive plate 25 is arranged on the first surface 201 of the device under test 2. The terminal 21 and the reference terminal 22 are electrically connected via the conductive plate 25, and the electrical resistance between the terminal 21 and the reference terminal 22 is zero. Similar to the inspection system 1 shown in FIG. 1, the measurement terminal 121 of the inspection system 1 shown in FIG. 6 is electrically connected to the reference terminal 22 when measuring electrical parameters.

[0066] 6, the measurement device 13 measures the electrical resistance between each probe 10 and the measurement terminal 121. Hereinafter, the total electrical resistance between the probe 10 and the measurement terminal 121 is also referred to as the "composite electrical resistance." The composite electrical resistance includes the variable electrical resistance R1.

[0067] 2, an example of a method for determining the parallelism between the inspection jig 11 and the device under test 2 using the inspection system 1 shown in FIG. 6 will be described below. First, in step S10, the gap adjustment device 18 sets the gap between the device under test 2 and the inspection jig 11 to a first facing distance D1. For example, the distance at which the probes 10 and the terminals 21 come into contact may be set to the first facing distance D1.

[0068] Next, in step S20, the switch 12 switches the probes 10 connected to the measuring device 13, and the measuring device 13 sequentially measures the combined electrical resistance at the first facing distance D1 for each probe 10 as an electrical parameter. Alternatively, the switch 12 electrically connects multiple probes 10 to the measuring device 13 at the same time, and the measuring device 13 measures the combined electrical resistance for the multiple probes 10 simultaneously. The measured combined electrical resistance is stored in the measurement value storage device 16 in association with the first facing distance D1 for each probe 10. For example, when the probe 10 and the terminal 21 are in contact at the first facing distance D1, the measured combined electrical resistance is zero Ω.

[0069] Next, in step S30, the gap adjusting device 18 sets the gap between the device under test 2 and the inspection jig 11 to a second facing distance D2 different from the first facing distance D1. For example, when the probe 10 and the terminal 21 come into contact with each other at the first facing distance D1, the second facing distance D2 is set to be longer than the first facing distance D1.

[0070] Next, in step S40, the measurement device 13 measures, as an electrical parameter, the combined electrical resistance at the second facing distance D2 for each probe 10. The measured combined electrical resistance is stored in the measurement value storage device 16 in association with the second facing distance D2 for each probe 10.

[0071] In step S50, the detection device 14 detects, for each probe 10, the amount of change in the combined electrical resistance caused by a change in the facing distance D, using the combined electrical resistance measured at the first facing distance D1 and the combined electrical resistance measured at the second facing distance D2. For example, the detection device 14 detects the difference between the combined electrical resistance measured at the first facing distance D1 and the combined electrical resistance measured at the second facing distance D2 as the amount of change in the combined electrical resistance caused by a change in the facing distance D (hereinafter also referred to as the "differential electrical resistance Rd"). The detected differential electrical resistance Rd is transmitted to the determination device 15. For example, when the probe 10 and the terminal 21 are in contact with each other at the first facing distance D1, the combined electrical resistance measured at the first facing distance D1 is zero Ω, and therefore the differential electrical resistance Rd is the combined electrical resistance measured at the second facing distance D2.

[0072] In step S60, the determination device 15 determines whether the object under test 2 and the inspection jig 11 are arranged in parallel based on the differential electrical resistance Rd. For example, the determination device 15 determines whether the differential electrical resistance Rd for each probe 10 is within a predetermined range of determination values. If the differential electrical resistance Rd for all probes 10 is within the range of determination values, the determination device 15 determines that the object under test 2 and the inspection jig 11 are arranged in parallel. On the other hand, if there is even one probe 10 whose differential electrical resistance Rd is not within the range of determination values, the determination device 15 determines that the object under test 2 and the inspection jig 11 are not arranged in parallel.

[0073] For example, when the probes 10 and the terminals 21 are in contact at the first facing distance D1, the determination device 15 determines that the device under test 2 and the inspection jig 11 are arranged in parallel if the combined electrical resistance measured at the second facing distance D2 is the open resistance value for all the probes 10. Here, the "open resistance value" is a resistance value that indicates that the probes 10 and the reference terminals 22 are separated from each other. The open resistance value is greater than the combined electrical resistance when the probes 10 and the terminals 21 are in contact at the first facing distance D1.

[0074] The first facing distance D1 and the second facing distance D2 are set to distances that allow a comparison of the combined electrical resistance at the first facing distance D1 and the combined electrical resistance at the second facing distance D2.

[0075] For example, the first facing distance D1 may be set to the distance at which the probes 10 and the terminals 21 contact each other, and the second facing distance D2 may be set to the distance at which the probes 10 and the terminals 21 are separated from each other. In this case, the measuring device 13 may confirm that the electrical resistance between all of the probes 10 and the reference terminals 22 at the first facing distance D1 is a short-circuit resistance value. Here, the "short-circuit resistance value" is a resistance value indicating that the probes 10 and the reference terminals 22 are in contact with each other, and is approximately zero Ω. The second facing distance D2 is set to the distance at which all of the probes 10 and the terminals 21 are separated from each other when the parallelism between the inspection jig 11 and the device under test 2 is within an allowable range.

[0076] When the first facing distance D1 is set so that all the probes 10 come into contact with the terminals 21, the second facing distance D2 may be set by, for example, the method shown in FIG.

[0077] 7, the gap adjusting device 18 sets the gap between the device under test 2 and the inspection jig 11 to a first facing distance D1. At this time, it may be confirmed that the combined electrical resistance of all the probes 10 is a short-circuit resistance value. Next, in step S32, the gap adjusting device 18 widens the gap between the device under test 2 and the inspection jig 11.

[0078] In step S33, the measuring device 13 measures the electrical resistance between any one of the multiple probes 10 and the reference terminal 22. For example, the measuring device 13 measures the electrical resistance between the first probe 101 and the reference terminal 22. Hereinafter, the electrical resistance value measured in step S33 will also be referred to as the "setting electrical resistance value."

[0079] In step S34, the measuring device 13 determines whether the setting electrical resistance value is an open resistance value. If the setting electrical resistance value is an open resistance value, the process proceeds to step S35, where the distance between the device under test 2 and the inspection jig 11 at that time is set to a second facing distance D2. Therefore, the second facing distance D2 is the distance between the probe 10 and the terminal 21. On the other hand, if the setting electrical resistance value is not an open resistance value in step S34, the process returns to step S32, where the distance between the device under test 2 and the inspection jig 11 is increased. Thereafter, the process proceeds to step S33.

[0080] When setting the first facing distance D1 so that all the probes 10 contact the terminals 21, care should be taken to ensure that the device under test 2 and the inspection jig 11 are somewhat parallel to each other before setting the first facing distance D1. If the inspection jig 11 is significantly tilted relative to the device under test 2, the probes 10 that come into strong contact with the terminals 21 at the first facing distance D1 may damage the terminals 21.

[0081] In the above description, the second facing distance D2 is longer than the first facing distance D1. Alternatively, the second facing distance D2 may be shorter than the first facing distance D1. For example, the facing distance D is narrowed from a state in which the facing distance D is sufficiently large and the composite electrical resistance is infinite to the first facing distance D1 at which the measurement device 13 can measure the composite electrical resistance. In this case, the facing distance D may be gradually narrowed while measuring the composite electrical resistance for any of the probes 10. Then, the facing distance D at which an effective composite electrical resistance is measured is set as the first facing distance D1. After measuring the composite electrical resistance at the first facing distance D1, the facing distance D is gradually shortened while measuring the composite electrical resistance for any of the probes 10 until the composite electrical resistance changes from the measured value at the first facing distance D1. Then, the facing distance D at which the composite electrical resistance changes from the measured value at the first facing distance D1 is set as the second facing distance D2.

[0082] Incidentally, the facing distance D may be changed while measuring the electrical resistance between the plurality of probes 10 and the reference terminal 22. In this case, the switch 12 selectively electrically connects two or more of the plurality of probes 10 held by the inspection jig 11 to the measuring device 13.

[0083] An example will be described below in which the switch 12 electrically connects the first probe 101 and the third probe 103 to the measuring device 13 at the same time. In this example, as will be described below, the measuring device 13 simultaneously measures the electrical resistance between the first probe 101 and the reference terminal 22 and the electrical resistance between the third probe 103 and the reference terminal 22.

[0084] While changing the facing distance D, the measuring device 13 simultaneously measures the electrical resistance between the first probe 101 and the reference terminal 22 (hereinafter referred to as the "first set resistance Rs1") and the electrical resistance between the third probe 103 and the reference terminal 22 (hereinafter referred to as the "third set resistance Rs3"). The detecting device 14 simultaneously monitors the first set resistance Rs1 and the third set resistance Rs3 measured by the measuring device 13. The detecting device 14 stops changing the facing distance D when at least one of the first set resistance Rs1 and the third set resistance Rs3 falls outside a predetermined resistance threshold range. The resistance threshold is an electrical resistance value that serves as a guide for detecting changes in the electrical resistance between the probe 10 and the terminal 21. By measuring the combined electrical resistance for each probe 10 after stopping the change in the facing distance D, the in-plane distribution of the combined electrical resistance in the XY plane can be obtained.

[0085] By obtaining the in-plane distribution of the combined electrical resistance, the parallelism between the inspection jig 11 and the device under test 2 can be efficiently determined. On the other hand, when the facing distance D is set based on the electrical resistance value between one probe 10 and the reference terminal 22, the following problem may occur. For example, when the tip of the third probe 103 is closer to the device under test 2 than the tip of the first probe 101, the third probe 103 and the third terminal 213 are in contact, but the first probe 101 is not in contact with the first terminal 211. In this case, when the combined electrical resistance is measured for all probes 10, it is difficult to determine the parallelism between the inspection jig 11 and the device under test 2 from the in-plane distribution of the combined electrical resistance.

[0086] In contrast to this, it is possible to detect the tendency of the in-plane distribution of the electrical resistance values ​​of the test object 2 by changing the facing distance D while measuring the electrical resistance between the multiple probes 10 and the reference terminal 22. By detecting the tendency of the in-plane distribution, it is possible to efficiently determine the parallelism between the inspection jig 11 and the test object 2.

[0087] In the above, an example has been described in which the switch 12 electrically connects the first probe 101 and the third probe 103 to the measuring device 13 at the same time, but any number of probes 10 may be connected to the measuring device 13 at the same time. Note that by simultaneously measuring the electrical resistance values ​​of the probes 10 arranged at the center and outer edge of the inspection jig 11, the effects of tilt and bending of the inspection jig 11 can be taken into consideration.

[0088] In the inspection system 1 described above in which the electrical parameter is electrical resistance, the parallelism between the object under test 2 and the inspection jig 11 is determined by a method of comparing the differential electrical resistance Rd of each of the probes 10 with a judgment value. However, the parallelism between the object under test 2 and the inspection jig 11 may also be determined by another method using the differential electrical resistance Rd.

[0089] For example, the inspection system 1 may determine that the device under test 2 and the inspection jig 11 are arranged parallel to each other when the difference between the maximum and minimum values ​​of the differential electrical resistances Rd detected for each of the probes 10 is within a predetermined range of judgment values. Alternatively, one of the multiple probes 10 may be selected as a reference probe, and the parallelism may be determined using the measurement value of the reference probe. That is, the inspection system 1 may determine that the device under test 2 and the inspection jig 11 are arranged parallel to each other when the difference between the differential electrical resistances Rd of all the probes 10 except the reference probe and the differential electrical resistance Rd of the reference probe is within a predetermined range of judgment values.

[0090] As described above, the inspection system 1 according to the second embodiment uses electrical resistance as an electrical parameter that changes due to a change in the facing distance D, and determines the parallelism between the inspection jig 11 and the object under test 2 based on the amount of change in electrical resistance. Otherwise, the second embodiment is substantially similar to the first embodiment, and therefore, redundant description will be omitted.

[0091] (Other embodiments) Although the present invention has been described above by way of the preferred embodiment, the descriptions and drawings that form part of this disclosure should not be understood as limiting the present invention. From this disclosure, various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art.

[0092] For example, in the above example, the facing distance D is changed by moving the inspection stage 181 on which the object under test 2 is placed in the Z direction. However, the facing distance D may also be changed by moving the inspection jig 11 in the Z direction.

[0093] Furthermore, although an example of inspecting the characteristics of the object under test 2 has been described above, the parallelism of the object under test 2 may be checked in order to perform an appearance inspection or a dimensional inspection of the object under test 2. After checking the parallelism of the object under test 2, another inspection system may be used instead of the inspection system 1 to inspect the characteristics of the object under test 2. For example, another inspection device may be connected to the inspection jig 11 to inspect the object under test 2.

[0094] Although the case where the object under test 2 is a printed circuit board has been described as an example, the object under test 2 may be something other than a printed circuit board. For example, the object under test 2 may be a semiconductor device formed on a wafer. When the object under test 2 is a semiconductor device, the inspection system 1 is used to inspect the electrical characteristics of the semiconductor device. Before inspecting the electrical characteristics of the semiconductor device, the inspection system 1 determines the parallelism between the inspection jig 11 and the wafer by measuring electrical parameters of the probes 10 that face terminals 21 formed on the semiconductor device.

[0095] Alternatively, the object under test 2 may be a metal plate or an insulating plate. The object under test 2 may also be an object to be processed. That is, after the parallelism of the object under test 2 is confirmed, the object under test 2 may be ground or polished using a processing device. The inspection system 1 can be suitably used to confirm the parallelism of the object under test 2, such as a flat plate, to be inspected or processed.

[0096] Thus, it goes without saying that the present invention includes various embodiments not described here. [Explanation of symbols]

[0097] 1. Inspection system 2...Test object 10...Probe 11...Inspection jig 12...Switch 13...Measuring equipment 14...Detection device 15...Judgment device 18…Space adjustment device 21...Terminal

Claims

1. An inspection system used to inspect the parallelism of an object to be inspected, an inspection jig having a plurality of probes arranged so that their tips face the object under inspection; a measuring device for measuring an electrical parameter that varies depending on the distance between the test object and the tip of each of the probes; a detection device that detects, for each of the probes, a change in the electrical parameter caused by a change in the distance using measured values ​​of the electrical parameter measured at each of the plurality of distances; a determination device that determines whether the object under test and the inspection jig are arranged in parallel based on the amount of change in the electrical parameter; An inspection system comprising:

2. 2. The inspection system according to claim 1, wherein the determination device determines that the object to be inspected and the inspection jig are arranged in parallel when the amount of change for all of the probes is within a range of a predetermined determination value.

3. 2. The inspection system according to claim 1, wherein the determination device determines that the object under test and the inspection jig are arranged parallel to each other when a difference between a maximum value and a minimum value of the amount of change detected for each of the probes is within a predetermined determination value range.

4. 2. The inspection system according to claim 1, wherein the determination device determines that the object under test and the inspection jig are arranged in parallel when one of the plurality of probes is used as a reference probe and the difference between the amount of change detected by all of the other probes excluding the reference probe and the amount of change detected by the reference probe is within a predetermined determination value range.

5. 5. The inspection system according to claim 4, wherein the probe for which a measured value of the electrical parameter measured for each of the probes is closest to an average value of the measured values ​​of the electrical parameter measured for each of the probes is selected as the reference probe.

6. The inspection system according to claim 1 , wherein the electrical parameter includes an electrical capacitance between the device under test and the tip of the probe.

7. 7. The inspection system of claim 6, wherein the distance at which the measurement device measures the electrical parameter includes a first opposing distance at which electrical capacitance between the device under test and the tip of the probe is zero, and a second opposing distance that is shorter than the first opposing distance.

8. The inspection system according to claim 1 , wherein the electrical parameter comprises an electrical resistance between the device under test and the tip of the probe.

9. 9. The inspection system of claim 8, wherein the distance at which the measurement device measures the electrical parameter includes a first opposing distance at which the probe contacts the device under test and a second opposing distance at which the probe and the device under test are separated.

10. The inspection system of claim 1 , wherein the measurement device measures the electrical parameters for a plurality of the probes simultaneously.

11. The inspection system according to claim 1 , wherein the probe is brought into contact with the object under test to inspect characteristics of the object under test.

12. An inspection jig having a plurality of probes is arranged so that the tips of the probes face the object to be inspected; For each of the probes, an electrical parameter is measured that varies depending on the distance between the test object and the tip; detecting, for each of the probes, a change in the electrical parameter due to a change in the distance using the measured values ​​of the electrical parameter measured at each of the plurality of distances; Based on the amount of change in the electrical parameter, it is determined whether the device under test and the inspection jig are arranged in parallel.

12. A testing method comprising:

13. 13. The inspection method according to claim 12, wherein it is determined that the device under test and the inspection jig are arranged in parallel when the amount of change for all of the probes is within a range of a predetermined determination value.

14. 13. The inspection method according to claim 12, wherein it is determined that the object to be inspected and the inspection jig are arranged parallel to each other when the difference between the maximum and minimum values ​​of the change amounts detected for each of the probes is within a predetermined judgment value range.

15. 13. The inspection method according to claim 12, wherein one of the plurality of probes is set as a reference probe, and if a difference between the amount of change detected by all of the other probes excluding the reference probe and the amount of change detected by the reference probe is within a range of a predetermined judgment value, it is determined that the object under test and the inspection jig are arranged in parallel.

16. 16. The inspection method according to claim 15, wherein the probe for which a measured value of the electrical parameter measured for each of the probes is closest to an average value of the measured values ​​of the electrical parameter measured for each of the probes is selected as the reference probe.

17. 17. The inspection method according to claim 12, wherein the electrical parameter includes an electrical capacitance between the device under test and the tip of the probe.

18. 18. The inspection method according to claim 17, wherein the distance when measuring the electrical parameter includes a first opposing distance at which the electrical capacitance between the device under test and the tip of the probe is zero, and a second opposing distance that is shorter than the first opposing distance.

19. 17. The inspection method according to claim 12, wherein the electrical parameter includes an electrical resistance between the device under test and the tip of the probe.

20. 20. The inspection method of claim 19, wherein the distance when measuring the electrical parameter includes a first opposing distance at which the probe contacts the device under test and a second opposing distance at which the probe and the device under test are separated.

21. 21. The inspection method according to claim 12, wherein the electrical parameters are measured simultaneously for a plurality of the probes.

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