Inspection device and test apparatus

Abstract

To detect an abnormality of a probe part for testing without directly examining the probe part in a semiconductor chip inspection.SOLUTION: An inspection device comprises: an image acquisition unit that acquires an image of an electrode after contact with a probe part; and a state detection unit that detects a state of a tip of the probe part on the basis of the image. The state detection unit may detect three states such as foreign matter adhesion to the tip of the probe part, wear of the tip of the probe part, and an abnormal contact angle of the tip of the probe part on the basis of a change region in the image.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an inspection device and a test device. [Background technology]

[0002] Conventionally, a probe inspection device that inspects the shape of the tip of a contact probe that is pressed against a contact pad of an integrated circuit is known (see, for example, Patent Document 1). Also known is a probe contact mark detection method for confirming contact between the electrodes of multiple semiconductor chips (dies) formed on a semiconductor wafer and the probe (see, for example, Patent Document 2). [Prior art document] [Patent documents] [Patent Document 1] JP 2008-191167 A [Patent Document 2] JP 2007-103860 A Summary of the Invention [Problem to be solved by the invention]

[0003] In the inspection of semiconductor chips, it is preferable to be able to detect abnormalities in the probe portion. [Means for solving the problem]

[0004] A first aspect of the present invention provides an inspection device. The inspection device may include an image acquisition unit that acquires an image of the electrode after the probe portion has contacted it. Any of the above inspection devices may include a state detection unit that detects the state of the tip of the probe portion based on the image.

[0005] In any of the above inspection devices, the condition detection unit may detect three conditions based on the changed area of ​​the image: adhesion of foreign matter to the tip of the probe unit, wear of the tip of the probe unit, or an abnormal contact angle of the tip of the probe unit.

[0006] In any of the above inspection devices, the state detection unit may detect three states, namely, the adhesion of foreign matter, the wear, or the abnormal contact angle, based on the color of the changed region.

[0007] In any of the above inspection devices, the state detection section may detect three states, namely, the adhesion of foreign matter, the wear, or the abnormal contact angle, based on the shape of the changed region.

[0008] In any of the inspection devices described above, the state detection section may detect wear of the probe section when the shape of the changed area in the image includes a central circle and double rings surrounding the central circle.

[0009] In any one of the inspection devices described above, the double ring may have an outer ring and an inner ring, and the condition detection unit may detect the wear based on a result of comparing the brightness of the outer ring and the central circle.

[0010] In any of the above inspection devices, when the luminance of the central circle is defined as a central luminance, the luminance of the inner ring is defined as an inner luminance, the luminance of the outer ring is defined as an outer luminance, and the average luminance of the image is defined as an overall luminance, one of the central luminance and the inner luminance may be higher than the overall luminance, and the other may be lower than the overall luminance. In any of the above inspection devices, one of the outer luminance and the inner luminance may be higher than the overall luminance, and the other may be lower than the overall luminance.

[0011] In any of the inspection devices described above, the state detection section may detect the wear by comparing the diameter of the central circle with the diameter of the probe section.

[0012] In any of the inspection devices described above, the state detection section may detect an abnormality in the contact angle of the probe section when the shape of the changed area in the image has a center circle and an arc portion along the center circle.

[0013] In any of the above inspection devices, when the brightness of the central circle is defined as the central brightness, the brightness of the arc portion is defined as the arc brightness, and the average brightness of the image is defined as the overall brightness, one of the central brightness and the arc brightness may be higher than the overall brightness, and the other may be lower than the overall brightness.

[0014] In any of the above-described inspection devices, a plurality of the probe portions may be in contact with the electrode. In any of the above-described inspection devices, the state detection unit may select the change region from which the state of the tip of the probe portion can be detected by comparing the arrangement of the plurality of probe portions with the arrangement of the change region.

[0015] In any of the above inspection devices, the condition detection unit may detect three conditions, namely, the adhesion of foreign matter, the wear, or the abnormal contact angle, based on changes in the changed area in two or more of the images acquired at different times.

[0016] In any of the above inspection devices, the shape of the change area may be a central circle and double rings surrounding the central circle. In any of the above inspection devices, the double rings may have an outer ring and an inner ring. In any of the above inspection devices, the condition detection unit may detect the wear when the diameter of the inner ring is increasing in two or more of the images acquired at different times.

[0017] In any of the above inspection devices, the state detection unit may notify the user when it is time to replace the probe unit based on a history of changes in the diameter of the inner circumferential ring.

[0018] In a second aspect of the present invention, there is provided a test device. The test device may include any one of the inspection devices described above. Any one of the test devices described above may include the probe unit.

[0019] The above summary of the invention does not list all of the necessary features of the present invention, and subcombinations of these features may also be inventions. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 shows a test apparatus 90 according to one embodiment of the present invention. [Figure 2] 10A and 10B are diagrams showing the state of the probe portion 24 and the corresponding image features of the electrode 14. FIG. [Figure 3] FIG. 10 is a diagram showing the relationship between the worn probe portion 24 and the size of the change area. [Figure 4] 10 is a diagram showing the positional relationship between a plurality of probe portions 24 and a change area on the surface of an electrode 14. FIG. [Figure 5] FIG. 10 is a diagram showing changes in change areas over time for each abnormal state. [Figure 6] FIG. 10 is a diagram showing the change in diameter d1 of the inner circumferential ring 44 over time. [Figure 7] 10 is a flowchart showing an example of a procedure for detecting the state of the tip of the probe section 24. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. In this specification, the same parts in each drawing are given the same reference numerals, and their description may be omitted. Furthermore, for the sake of convenience, some components may not be illustrated.

[0022] In this specification, when we say "same" or "equal," it may include cases where there is an error due to manufacturing variations, etc. The error is, for example, within 10%.

[0023] 1 is a diagram showing a test apparatus 90 according to one embodiment of the present invention. The test apparatus 90 tests a semiconductor chip 10. The test apparatus 90 of this example performs an electrical test of the semiconductor chip using a test probe 20. The test apparatus 90 includes the test probe 20 and an inspection apparatus 30.

[0024] The semiconductor chip 10 has a semiconductor substrate 12 and an electrode 14. The semiconductor substrate 12 is, for example, a silicon substrate or a silicon carbide substrate. An element structure such as a transistor or a diode is formed on the semiconductor substrate 12. The electrode 14 is formed above the main surface of the semiconductor substrate 12, and at least a portion of it is exposed on the surface of the semiconductor chip 10. For example, if the semiconductor substrate 12 is a transistor, the electrode 14 is a source electrode or an emitter electrode. Other members such as a protective film may be provided on the surface of the semiconductor chip 10, but are omitted in this example.

[0025] The test probe 20 has a contact block 22 and a probe portion 24. In this example, a plurality of probe portions 24 are attached to the contact block 22. The probe portions 24 are brought into contact with the electrodes 14 of the semiconductor chip 10 to perform an electrical test on the semiconductor chip 10. In this example, the probe portions 24 are conductive members formed in a rod shape. FIG. 1 schematically shows how the test probes 20 are brought into contact with a number of semiconductor chips 10 to perform tests sequentially.

[0026] The inspection device 30 estimates the state of the probe portion 24 by examining the electrodes 14 of the semiconductor chip 10 after the test. In Fig. 1, the semiconductor chip 10 after the test has been moved to a position facing the inspection device 30. The inspection device 30 includes an image acquisition unit 32 and a state detection unit 34.

[0027] The image acquisition unit 32 acquires an image of the electrode 14 after the probe portion 24 has come into contact with it. As an example, the image acquisition unit 32 is a CCD image sensor. The image acquisition unit 32 outputs the acquired image to the state detection unit 34.

[0028] The condition detection unit 34 detects the condition of the tip of the probe unit 24 based on the image acquired by the image acquisition unit 32. The tip of the probe unit 24 is the portion of the probe unit 24 that comes into contact with the electrode 14. As will be described later, the image of the electrode 14 reflects the condition of the tip of the probe unit 24. Therefore, the condition detection unit 34 can estimate the condition of the tip of the probe unit 24 based on the image of the electrode 14. In this case, the condition detection unit 34 may detect the condition of the tip of the probe unit 24 only from the image of the electrode 14. In other words, the condition of the tip of the probe unit 24 may be detected without further inspecting the condition of the probe unit 24 using a separate method. This makes it possible to discover abnormalities in the probe unit 24 early on using a simple device.

[0029] Generally, in the manufacturing process of a semiconductor device, a visual inspection of the semiconductor chip 10 is performed. The image acquisition unit 32 may take an image for the visual inspection. The state detection unit 34 may acquire an image for the visual inspection. This makes it possible to detect the state of the probe unit 24 without adding a new process. The image acquisition and state detection described above may be performed as part of an automatic visual inspection, which automatically inspects the appearance.

[0030] As will be described later, the image of the electrode 14 reflects the type of condition of the tip of the probe section 24. Therefore, the condition detection section 34 may determine not only whether or not there is an abnormality in the probe section 24, but also the type of abnormality. The condition detection section 34 may detect at least two types of abnormalities in the tip of the probe section 24, or may detect at least three types of abnormalities in the tip of the probe section 24, based on the image of the electrode 14.

[0031] The illumination used when the image acquisition unit 32 acquires an image of the electrode 14 may be coaxial illumination. Coaxial illumination is illumination using coaxial light, which is highly directional and has a low degree of diffusion. The coaxial light may be parallel light. The coaxial light may be incident on the electrode 14 at a single incident angle and emitted from the electrode 14 at a single exit angle. When the coaxial light is irradiated onto a flat portion of the electrode 14, the incident angle and the exit angle may be the same. As an example, the light source that irradiates the coaxial light is a laser light source.

[0032] 2 is a diagram showing the states of the probe section 24 and the corresponding image features of the electrode 14. The first line shows four states of the probe section 24. The second line shows a schematic diagram of the image and the third line shows an explanation of the image as the image features corresponding to each state.

[0033] The leftmost column in Figure 2 shows a case where the probe portion 24 is in a normal state. In this case, the image of the electrode 14 shows almost no contact marks of the probe portion 24. In the electrode image in Figure 2, the original color of the electrode surface is represented by hatching.

[0034] The second column from the left in FIG. 2 shows a case where a foreign substance is attached to the tip of the probe portion 24. In this case, a circular black area appears in the image of the electrode 14. This area is designated as the black circular area 40. This is because the probe portion 24 with the foreign substance attached comes into contact with the electrode 14, causing part of the foreign substance to adhere to the surface of the electrode 14. However, the shape of the black circular area 40 may be an ellipse. It may also be a shape other than a circle.

[0035] The third column from the left in Fig. 2 shows a case where the tip of the probe portion 24 has worn away. The schematic diagram of the state of the probe portion 24 shown in the first row in this case is an enlarged view of the tip of the probe portion 24, showing a state where the probe portion 24 has worn away from a new state. The black arrows in the figure indicate the stress applied to the electrode 14 when the probe portion 24 comes into contact with the electrode 14.

[0036] When the probe portion 24 is new, the tip is spherical (curved in cross section). This distributes the stress generated in the electrode 14. However, as wear progresses, the tip becomes flat. This causes the load to be applied differently, and shear stress occurs outside the flat portion of the probe portion 24.

[0037] When the tip of the probe portion 24 is worn, a central circle 42 and a double ring 48 surrounding the central circle 42 appear in the electrode image. The central circle 42 appears white because it is brighter than the surface of the electrode 14. The double ring 48 includes an outer ring 46 and an inner ring 44. The inner ring 44 surrounds the central circle 42, and the outer ring 46 surrounds both the inner ring 44 and the central circle 42. The outer ring 46 appears white because it is brighter than the surface of the electrode 14. The inner ring 44 appears black because it is less bright than the surface of the electrode 14. Wear of the probe portion 24 changes the shape of the tip, which in turn changes the load applied to the electrode 14, resulting in the appearance of the above-mentioned pattern. In particular, the white outer ring 46 is thought to be due to shear stress generated in the electrode 14. Performing a test with a worn tip of the probe portion 24 can result in problems, such as the measured current value deviating from the set value.

[0038] The shapes of the center circle 42, the inner ring 44, and the outer ring 46 may be ellipses. The shapes of the center circle 42, the inner ring 44, and the outer ring 46 may correspond to the shape of the tip of the probe portion 24. Furthermore, the inner ring 44 and the outer ring 46 do not have to be complete, seamless rings. The inner ring 44 and the outer ring 46 may have portions missing. For example, if 80% or more of the circumference is visible, it may be considered to be the inner ring 44 or the outer ring 46. The center circle 42 may also have portions missing.

[0039] The fourth column from the left in Figure 2 shows a case where the contact angle of the probe portion 24 is inappropriate (abnormal contact angle). The contact angle is the angle of the tip of the probe portion 24 relative to the surface of the electrode 14. In a normal probe portion 24, this angle is 90° in all cross sections perpendicular to the surface of the electrode 14. However, in a case where the contact angle is inappropriate, the angle is smaller than 90° in a specific cross section. The schematic diagram of the state of the probe portion 24 shown in the first row shows the cross section with the smallest contact angle among the specific cross sections, and the contact angle is indicated by α. In a case where the contact angle is inappropriate, a different load is applied than in a normal case. However, an abnormal contact angle may include a case where the probe portion 24 is bent not only at the tip but also from the base.

[0040] If the contact angle of the probe portion 24 is inappropriate, a central circle 42 and an arc portion 50 will appear in the electrode image. The central circle 42 appears white because it is brighter than the surface of the electrode 14. The arc portion 50 appears black because it is brighter than the surface of the electrode 14. The arc portion 50 is formed in an arc shape along the central circle 42. The shape of the arc portion 50 does not have to be a complete, seamless ring. The arc portion 50 may be partially missing. For example, if 40% or more of the circumference is visible, it may be considered an arc portion 50. Note that in this example, the central circle 42 may also be an ellipse. The central circle 42 in this example may also be partially missing.

[0041] The center of the arc portion 50 may be offset in a specific direction relative to the center of the central circle 42. The specific direction may correspond to the contact angle of the probe portion 24. In other words, in the cross section where the contact angle is smallest, the arc portion 50 may be offset in the opposite direction from the probe portion 24 with respect to the central circle 42. It is believed that the center of the arc portion 50 is offset due to stress generated in the electrode 14 when the contact angle of the probe portion 24 is inappropriate. However, the arc portion 50 may also surround the central circle.

[0042] Here, the average brightness of the entire electrode image is defined as the overall brightness. A region that has a brightness difference of a predetermined value or more from the overall brightness and has an area equal to or greater than the predetermined value is referred to as a change region. The predetermined brightness value may be determined based on the brightness of at least one of the black circle region 40, the central circle 42, the inner ring 44, the outer ring 46, or the arc portion 50. An area equal to or greater than the predetermined value is, for example, 10% or more of the cross-sectional area of ​​the probe portion 24. The black circle region 40, the central circle 42, the inner ring 44, the outer ring 46, and the arc portion 50 are examples of change regions. The procedure for determining a change region will be described later.

[0043] The condition detection unit 34 may detect three conditions based on the changed area of ​​the image: foreign matter adhesion to the tip of the probe unit 24, wear of the tip of the probe unit 24, or an abnormal contact angle of the tip of the probe unit 24. As an example, the condition detection unit 34 detects the three conditions of foreign matter adhesion, wear, or an abnormal contact angle based on the color of the changed area. Here, color may refer to a level of brightness. A "white" color may mean that the brightness is higher than the overall brightness by a predetermined value or more. Similarly, a "black" color may mean that the brightness is lower than the overall brightness by a predetermined value or more. For example, the condition detection unit 34 detects foreign matter adhesion to the tip when only a black area is found in the changed area, detects an abnormal contact angle when a black area and a white area are found, and detects wear of the tip when a black area and two white areas are found.

[0044] The condition detection unit 34 may detect three conditions based on the shape of the changed area: foreign matter adhesion, wear, or abnormal contact angle. For example, the condition detection unit 34 may detect foreign matter adhesion to the tip when only a single area is confirmed in the changed area. The condition detection unit 34 may detect abnormal contact angle when the shape of the changed area includes a center circle 42 and an arc portion 50 along the center circle 42. The condition detection unit 34 may detect wear when the shape of the changed area includes a center circle 42 and a double ring 48 surrounding the center circle 42. In another example, the condition detection unit 34 may detect abnormal contact angle when two areas with different brightnesses are confirmed in the changed area, and may detect wear when three areas with different brightnesses are confirmed.

[0045] The condition detection unit 34 may detect three conditions—foreign matter adhesion, wear, or abnormal contact angle—based on both the color and shape of the changed area. That is, the color characteristics of the changed area and the shape characteristics of the changed area may be combined to detect the three conditions—foreign matter adhesion, wear, or abnormal contact angle. For example, the condition detection unit 34 detects wear based on a comparison of the brightness of the outer ring 46 and the inner ring 44. When the probe unit 24 is in a normal state, the color of the outer ring 46 is light. As wear of the probe unit 24 progresses, the color of the outer ring 46 becomes darker. Therefore, by comparing the brightness of the outer ring 46 and the inner ring 44, it is possible to detect the presence or absence of wear and the progress of the wear. The comparison result may be the difference in brightness. The condition detection unit 34 may also detect wear based on a comparison of the brightness of the outer ring 46 and the center circle 42. In this case, as wear progresses, the difference in brightness between the outer ring 46 and the center circle 42 becomes smaller.

[0046] In the example of the electrode image in Fig. 2, the central circle 42 and the outer peripheral ring 46 are displayed in white (i.e., at a higher brightness than the overall brightness), and the black circular area 40, the inner peripheral ring 44, and the arc portion 50 are displayed in black (i.e., at a lower brightness than the overall brightness). In other examples, the electrode image may be an image in which black and white are reversed from the electrode image shown in Fig. 2. In this electrode image, the central circle 42 and the outer peripheral ring 46 are displayed in black (i.e., at a lower brightness than the overall brightness), and the black circular area 40, the inner peripheral ring 44, and the arc portion 50 are displayed in white (i.e., at a higher brightness than the overall brightness).

[0047] In the example where the tip of the probe portion 24 is worn, the brightness of the central circle 42 is referred to as the central brightness, the brightness of the inner ring 44 as the inner brightness, and the brightness of the outer ring 46 as the outer brightness. These brightnesses may be the average brightness in each region. One of the central brightness and the inner brightness is higher than the overall brightness, and the other is lower than the overall brightness. As in the example of Figure 2, when the central circle 42 is white, the inner ring 44 may be black. Also, one of the outer brightness and the inner brightness is higher than the overall brightness, and the other is lower than the overall brightness. As in the example of Figure 2, when the outer ring 46 is white, the inner ring 44 may be black.

[0048] In the example where the contact angle of the probe portion 24 is abnormal, the brightness of the central circle 42 is defined as the central brightness, and the brightness of the arc portion 50 is defined as the arc brightness. These brightnesses may be the average brightness in each region. One of the central brightness and the arc brightness is higher than the overall brightness, and the other is lower than the overall brightness. As in the example of Figure 2, when the central circle 42 is white, the arc portion 50 may be black.

[0049] FIG. 3 is a diagram showing the relationship between the worn probe portion 24 and the size of the change region. The tip of the probe portion 24 shown in FIG. 3 is worn and flattened. The electrode 14 shown in FIG. 3 has a central circle 42 and a double ring 48 formed thereon. In FIG. 3, the diameter of the central circle 42 is d1, and the diameter of the probe portion 24 is d2. The diameter of the probe portion 24 may be the diameter of the cylindrical portion, not the tip formed by wear.

[0050] The condition detection unit 34 may detect wear by comparing the diameter d1 of the center circle 42 with the diameter d2 of the probe portion 24. For example, if a foreign object adheres to the tip of the probe portion 24 or if a foreign object adheres directly to the surface of the electrode 14, the diameter of the change area caused by the foreign object may be larger than the diameter of the probe portion 24. Therefore, the condition detection unit 34 may detect wear when the diameter d1 of the center circle 42 is smaller than the diameter d2 of the probe portion 24. Furthermore, if the diameter d1 is smaller than the diameter d2, the condition detection unit 34 may inspect the color and shape of the double ring 48 described above. If the diameter d1 of the center circle 42 is more than twice the diameter d2 of the probe portion 24, the condition detection unit 34 may determine that wear is not due to wear of the tip of the probe portion 24. The condition detection unit 34 may detect wear by comparing the diameter d2 of the probe portion 24 with the diameter d1 of the inner circumferential ring 44 instead of the diameter d1 of the center circle 42. The diameter of the inner circumferential ring 44 may also be smaller than the diameter of the probe portion 24.

[0051] As described above, the outer ring 46 is believed to be caused by shear stress occurring outside the flat portion at the tip of the worn probe portion 24. Therefore, the diameter of the outer ring 46 may be larger than the diameter of the flat portion at the tip of the probe portion 24, and may be larger than the diameter d2 of the probe portion 24.

[0052] FIG. 4 is a diagram showing the positional relationship between multiple probe portions 24 and change areas on the surface of electrode 14. Test probe 20 has multiple probe portions 24. During testing, multiple probe portions come into contact with electrode 14. As a result, change areas are formed on electrode 14. Multiple change areas may be formed on electrode 14. In FIG. 4, two change areas, 62-1 and 62-2, are formed.

[0053] The probe contact area 60 shown in FIG. 4 represents the area where the probe section 24 comes into contact with the electrode 14. The state detection unit 34 may select a change area 62 that can detect the state of the tip of the probe section 24 by comparing the arrangement of the multiple probe sections 24 with the arrangement of the change area 62. The arrangement of the multiple probe sections 24 may be the arrangement of the probe contact areas 60. In this example, the two change areas 62-1 overlap with the probe contact areas 60, so it can be assumed that they are change areas that reflect the state of the probe sections 24. On the other hand, the change area 62-2 does not overlap with the probe contact area 60, so it can be assumed that they are not change areas that reflect the state of the probe sections 24, but rather that they are foreign matter that is directly attached to the surface of the electrode 14, for example. This makes it possible to prevent the state of the probe section 24 from being erroneously detected.

[0054] Figure 5 shows how the change area changes over time for each abnormal state. Starting from the top row, it shows the cases of foreign matter adhesion, tip wear, and contact angle abnormality. Also, the time elapses from the left column to the right column. The passage of time means an increase in the number of tests.

[0055] The condition detection unit 34 may detect three conditions, namely, foreign matter adhesion, wear, or abnormal contact angle, based on changes in the changed area in two or more images acquired at different times. The images may be images acquired of different electrodes 14 (different semiconductor chips 10). The condition detection unit 34 may detect three conditions, namely, foreign matter adhesion, wear, or abnormal contact angle, based on changes in the color of the changed area in two or more images acquired at different times, and may detect three conditions, namely, foreign matter adhesion, wear, or abnormal contact angle, based on changes in the shape of the changed area.

[0056] In the case of foreign matter adhesion, the area of ​​the black circle region 40 decreases over time. This is thought to be because as the test is performed, the foreign matter attached to the tip of the probe portion 24 adheres (moves) to the surface of the electrode 14, reducing the amount of foreign matter attached to the tip of the probe portion 24. The state detection unit 34 may detect foreign matter adhesion when the area of ​​the changed region decreases in two or more images acquired at different times.

[0057] In the case of wear, the area of ​​the change region, which is the combined area of ​​the central circle 42 and the double ring 48, increases over time. This is thought to be because wear progresses and the flat areas increase. The condition detection unit 34 may detect wear when the diameter d3 of the inner ring 44 increases in two or more images acquired at different times. The diameter d3 of the inner ring 44 increases over time. The condition detection unit 34 may also detect wear when the diameter d1 of the central circle 42 (see FIG. 3) increases over time. The inspection device 30 may further include a storage unit that stores the diameters of the inner ring 44 or the central circle 42 in past images. In the case of wear, the outer ring 46 becomes more clearly visible over time.

[0058] In the case of a contact angle abnormality, the area of ​​the change region, which is the combination of the central circle 42 and the arc portion 50, also increases over time. This is thought to be because the contact angle decreases over time. Furthermore, the contact angle decreases over time, and the load applied to the electrode 14 changes, causing the center of the arc portion 50 to move. The center of the arc portion 50 moves away from the center of the central circle 42 over time. The state detection unit 34 may detect a contact angle abnormality if the center of the arc portion 50 moves in two or more images acquired at different times.

[0059] Fig. 6 is a diagram showing the change over time in diameter d3 of the inner circumferential ring 44. The horizontal axis of Fig. 6 represents time, and the vertical axis represents diameter d3 of the inner circumferential ring 44. In Fig. 6 as well, the passage of time refers to an increase in the number of tests.

[0060] The state detection unit 34 measures the diameter d3 of the inner circumferential ring 44 from images of the electrode 14 acquired at different times. In FIG. 6, the measurement results are plotted as black circles. The measurement results from the past to the present are used as a change history. The state detection unit 34 may notify the user when to replace the probe unit 24 based on the change history of the diameter d3 of the inner circumferential ring 44. The state detection unit 34 may predict the future value of the diameter d3 of the inner circumferential ring 44 by approximating the change history of the diameter d3 of the inner circumferential ring 44. In FIG. 6, the change history of the diameter d3 of the inner circumferential ring 44 is approximated by a straight line, and the future value of the diameter d3 of the inner circumferential ring 44 is predicted using the approximated straight line (solid line in the figure).

[0061] As an example, the state detection unit 34 may determine that the replacement time t is the time when the predicted value of the diameter d3 of the inner circumferential ring 44 becomes equal to the diameter d2 of the probe unit 24. When the value of the diameter d3 of the inner circumferential ring 44 becomes equal to the diameter d2 of the probe unit 24, it is considered that wear at the tip of the probe unit 24 has progressed significantly, and therefore the probe unit 24 can be replaced based on the above notification. The replacement time t may be the time when the predicted value of the diameter d3 of the inner circumferential ring 44 becomes 90% or 80% of the diameter d2 of the probe unit 24.

[0062] As another example, the state detection unit 34 may acquire in advance the value of the diameter of the inner circumferential ring 44 when worn, and compare that value with a predicted value calculated from the change history. For example, the state detection unit 34 may determine that the replacement time t is the time when the predicted value of the diameter d1 of the inner circumferential ring 44 becomes equal to that value. The state detection unit 34 may notify the replacement time of the probe unit 24 based on the change history of the diameter d1 of the center circle 42 using the method described above.

[0063] 7 is a flowchart showing an example of a procedure for detecting the state of the tip of the probe portion 24. The detection procedure includes an image reading step S100, an averaging step S102, a dynamic threshold processing step S104, a noise removal step S106, an area detection step S108, a binarization step S110, an area detection step S112, a binarization step S114, and an area detection step S116.

[0064] In the image reading step S100, the state detection unit 34 reads the image of the electrode 14 acquired by the image acquisition unit 32. The image read at this time is referred to as an original image.

[0065] In the averaging step S102, the state detection unit 34 creates an image by averaging the luminance of the original image for each pixel. The image created at this time is called an average image. The luminance of the average image may be the overall luminance described above.

[0066] In the dynamic threshold processing step S104, regions where the difference in brightness between the original image and the average image is equal to or greater than a predetermined value are extracted. These regions are regions where the brightness varies relative to the surface of the electrode 14. The predetermined value may be determined based on the brightness of at least one of the black circle region 40, the central circle 42, the inner ring 44, the outer ring 46, or the arc portion 50 described above.

[0067] In the noise removal step S106, noise-caused regions are removed from the regions extracted in the dynamic threshold processing step S104. As an example, regions with an area equal to or smaller than a predetermined value are removed as noise-caused regions. As a result, the remaining regions become change regions. As an example, the predetermined value is 10% of the cross-sectional area of ​​the probe portion 24.

[0068] However, it is not necessary to perform the averaging process step S102 and the dynamic threshold process step S104. If the surface of the electrode 14 has a uniform brightness, it is also possible to directly extract from the original image a region having a brightness equal to or greater than a predetermined value.

[0069] In the area detection step S108, the state detection unit 34 checks whether a black change area exists. A black change area is an area within the change area that has a brightness lower than the overall brightness. Since a black change area is detected in any of the cases of foreign matter adhesion, wear, and abnormal contact angle described above, if a black change area does not exist, the probe unit 24 is determined to be normal. If a black change area exists, the state detection unit 34 proceeds to the binarization step S110.

[0070] In the binarization step S110, the state detection unit 34 binarizes the change area. That is, the change area is divided into a black change area and a white change area. A white change area is an area within the change area that has a brightness greater than the overall brightness.

[0071] In the region detection step S112, the status detection unit 34 checks whether or not a white change region exists. As described above, in the case of foreign matter adhesion, only black change regions are detected. Therefore, if a white change region does not exist, it may be determined that foreign matter is attached to the tip of the probe unit 24 (defective determination). In this case, the status detection unit 34 may notify the outside that foreign matter has adhered. This allows appropriate measures to be taken, such as cleaning the tip of the probe unit 24. The status detection unit 34 may also notify the outside to clean the tip of the probe unit 24. If a white change region exists, the status detection unit 34 proceeds to the binarization step S114.

[0072] In the binarization step S114, the state detection unit 34 binarizes the outer peripheral portion outside the black changed region. The outer peripheral portion is a region having a predetermined width extending outward from the boundary of the black changed region.

[0073] In the region detection step S116, the status detection unit 34 checks whether or not a white ring-shaped region exists in the outer periphery. As described above, in the case of wear, a white outer ring 46 is formed. Therefore, if a white ring-shaped region exists, it may be determined that the tip of the probe unit 24 is worn (defective). In this case, the status detection unit 34 may notify the outside of the wear. This allows appropriate measures to be taken, such as replacing the probe unit 24. The status detection unit 34 may also notify the outside of the request to replace the probe unit 24.

[0074] On the other hand, in the case of an abnormal contact angle, a white center circle 42 is present in part of the outer periphery, but no white ring-shaped region is present. In this way, if no white ring-shaped region is present, it may be determined that the contact angle of the tip of the probe unit 24 is inappropriate (defective). In this case, the status detection unit 34 may notify the outside of the abnormal contact angle. This allows appropriate measures to be taken, such as replacing the probe unit 24. The status detection unit 34 may also notify the outside of the request to replace the probe unit 24.

[0075] The notification may be made when the same defective judgment is made a predetermined number of times or more consecutively in different images. This makes it possible to suppress notifications due to erroneous detections. In addition, in the case of foreign matter adhesion, it is possible that performing a test will remove the foreign matter from the tip of the probe portion 24, and the probe portion 24 will return to normal. On the other hand, in the case of wear or an abnormal contact angle, it is unlikely that the probe portion 24 will return to normal even if a test is performed. Therefore, the predetermined number of times in the case of wear or an abnormal contact angle may be set lower than the predetermined number of times in the case of foreign matter adhesion.

[0076] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0077] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, flowcharts, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order. [Explanation of symbols]

[0078] 10...Semiconductor chip, 12...Semiconductor substrate, 14...Electrode, 20...Test probe, 22...Contact block, 24...Probe section, 30...Inspection device, 32...Image acquisition section, 34...Status detection section, 40...Black circle area, 42...Central circle, 44...Inner ring, 46...Outer ring, 48...Double ring, 50...Arc portion, 60...Probe contact area, 62...Change area, 90...Test device

Claims

1. an image acquisition unit that acquires an image of the electrode after the probe unit has come into contact with the electrode; a state detection unit that detects the state of the tip of the probe unit based on the image; An inspection device comprising:

2. The state detection unit detects three states based on a changed area of ​​the image: adhesion of a foreign substance to the tip of the probe unit; wear of the tip of the probe unit; and an abnormal contact angle of the tip of the probe unit. The inspection device according to claim 1 .

3. The state detection unit detects three states, namely, the adhesion of foreign matter, the wear, and the abnormal contact angle, based on the color of the changed region. The inspection device according to claim 2 .

4. The state detection unit detects three states, namely, the adhesion of foreign matter, the wear, and the abnormal contact angle, based on the shape of the change area.

4. The inspection device according to claim 2 or 3.

5. The state detection unit detects wear of the probe unit when the shape of the changed area of ​​the image includes a center circle and a double ring surrounding the center circle. The inspection device according to claim 1 .

6. The double ring has an outer ring and an inner ring, The state detection unit detects the wear based on a comparison result between the brightness of the outer ring and the brightness of the center circle. The inspection device according to claim 5 .

7. When the brightness of the central circle is defined as the central brightness, the brightness of the inner ring is defined as the inner brightness, the brightness of the outer ring is defined as the outer brightness, and the average brightness of the image is defined as the overall brightness, one of the central luminance and the inner peripheral luminance is higher than the overall luminance, and the other is lower than the overall luminance; One of the outer periphery luminance and the inner periphery luminance is higher than the overall luminance, and the other is lower than the overall luminance. The inspection device according to claim 6.

8. The state detection unit detects the wear by comparing the diameter of the center circle with the diameter of the probe unit. The inspection device according to claim 5 .

9. The state detection unit detects an abnormality in the contact angle of the probe unit when the shape of the changed area of ​​the image has a center circle and an arc portion along the center circle. The inspection device according to claim 1 .

10. When the brightness of the central circle is the central brightness, the brightness of the arc portion is the arc brightness, and the average brightness of the image is the overall brightness, One of the center luminance and the arc luminance is higher than the overall luminance, and the other is lower than the overall luminance. The inspection device according to claim 9.

11. A plurality of the probe portions contact the electrodes, The state detection unit selects the change area that can detect the state of the tip of the probe unit by comparing the arrangement of the plurality of probe units with the arrangement of the change area. The inspection device according to claim 2 .

12. The state detection unit detects the three states of the foreign matter adhesion, the wear, and the contact angle abnormality based on changes in the changed region in two or more of the images acquired at different times. The inspection device according to claim 2 .

13. the shape of the change area is a central circle and a double ring surrounding the central circle, The double ring has an outer ring and an inner ring, The state detection unit detects the wear when the diameter of the inner circumferential ring increases in two or more of the images acquired at different times. The inspection device according to claim 12.

14. The state detection unit notifies the user when it is time to replace the probe unit based on a history of changes in the diameter of the inner circumferential ring. The inspection device according to claim 13.

15. The inspection device according to claim 1 ; The probe portion A test device comprising:

Images