Electrical circuit inspection system with modulator maintenance unit

Abstract

To make it possible to perform more efficient cleaning and / or detection of a modulator.SOLUTION: An electrical circuit inspection system of the present disclosure includes: a chuck configured to support an electrical circuit; a modulator 31 movable above the chuck and positioned above the electrical circuits and configured to detect defects in the electrical circuits; and a modulator maintenance unit 50 comprising at least one of cleaning means for removing foreign matter from a surface of the modulator and detecting means for detecting flatness of the surface of the modulator. The modulator 31 is movable and can be positioned next to the modulator maintenance unit 50.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an electrical circuit inspection system having a modulator maintenance unit. [Background technology]

[0002] Liquid crystal display (LCD) panels incorporate liquid crystals that exhibit electric-field-dependent light-modulating properties. They are often used to display images and other information in a variety of devices, from facsimile machine and laptop computer screens to large-screen high-definition TVs. Active-matrix LCD panels have complex multilayer structures, consisting of several functional layers, such as deflection films, a TFT glass substrate incorporating thin-film transistors, storage capacitors, pixel electrodes, and interconnecting wiring, a color filter glass substrate incorporating a black matrix, color filter array, and transparent common electrode, a polyimide alignment film, and the actual liquid crystal material, along with plastic / glass spacers to maintain the proper LCD cell thickness. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2012-519390 Summary of the Invention [Problem to be solved by the invention]

[0004] LCD and OLED panels are manufactured under highly controlled conditions in clean room environments to maximize yields. Nevertheless, manufacturing failures force the disposal of large numbers of LCD and OLED panels.

[0005] As mentioned above, to improve the production yield of complex electronic devices, various inspection steps are performed to identify various defects that may occur at various stages of the manufacturing process. These inspection steps can be performed between manufacturing steps or after the entire manufacturing process is complete. One example of such an inspection process is the testing of TFT arrays for LC and OLED displays for electrical defects. Various inspection equipment is used to perform this testing. An example of an equipment that can be used for this purpose is the Array Checker™ commercially available from Orbotech Ltd. [Means for solving the problem]

[0006] According to one or more embodiments of the present disclosure, an electrical circuit inspection system can be provided that includes a chuck configured to support electrical circuits, a modulator that is movable above the chuck and positioned above the electrical circuits and configured to detect defects in the electrical circuits, and a modulator maintenance unit that includes at least one of a cleaning means for removing foreign matter from the surface of the modulator and a detection means for detecting the flatness of the surface of the modulator, wherein the modulator is movable and can be positioned next to the modulator maintenance unit.

[0007] According to one embodiment, the modulator can be configured to be positioned next to the modulator maintenance unit i) before testing of the electrical circuits begins, ii) after testing of the electrical circuits is completed, or iii) during testing operations of the electrical circuits.

[0008] According to one embodiment, the cleaning means may comprise one or more air knives.

[0009] According to one embodiment, the detection means may include one or more laser sensors each having a laser light emitting unit and a laser light receiving unit.

[0010] According to one embodiment, the laser emitting unit is configured to emit laser light in a direction parallel to a surface of the modulator positioned between the laser emitting unit and the laser receiving unit, and the laser light emitted from the laser emitting unit can be partially overlapped on the surface of the modulator.

[0011] According to one embodiment, the laser receiving unit can be configured to detect changes in laser light intensity due to lateral movement of the modulator positioned between the laser emitting unit and the laser receiving unit.

[0012] According to one embodiment, the system may further include a control unit that determines whether or not at least one of a convex portion and a concave portion is present on the surface of the modulator based on a change in the laser light intensity detected by the laser receiving unit.

[0013] According to one embodiment, the system can be configured to cause the cleaning means to remove foreign matter from the surface of the modulator if the control unit determines that a protrusion is present on the surface of the modulator.

[0014] According to one embodiment, the system can be configured to generate an abnormality signal by the control unit if the control unit determines that at least one of a protrusion and a recess is present on the surface of the modulator.

[0015] According to one embodiment, the modulator maintenance unit may comprise the cleaning means and the detection means, and may be configured to simultaneously perform a cleaning operation by the cleaning means and a detection operation by the detection means when the modulator is positioned adjacent to the modulator maintenance unit.

[0016] According to one embodiment, the modulator maintenance unit can include the cleaning means and suction means for sucking up foreign matter removed from the surface of the modulator by the cleaning means.

[0017] According to one embodiment, the modulator maintenance unit may be provided with two cleaning means, the suction means being located between the two cleaning means.

[0018] According to one embodiment, the modulator maintenance unit may be positioned on a side of the chuck.

[0019] According to one embodiment, the modulator maintenance unit may be located on one side of the chuck, particularly on one of the sides of the chuck adjacent to the front of the inspection system.

[0020] According to one embodiment, the modulator maintenance unit may be located on one side of the chuck, particularly on one of the sides of the chuck adjacent to the rear of the inspection system.

[0021] According to one embodiment, the modulator maintenance unit can be positioned on one side of the chuck, particularly on one of the sides of the chuck adjacent to the point where the modulator begins testing the electrical circuit.

[0022] Those skilled in the art will be able to better appreciate the many advantages of the present disclosure by reviewing the accompanying drawings, in which: [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a conceptual diagram illustrating an inspection system (100) according to one or more embodiments of the present disclosure. [Figure 2] FIG. 1 is a conceptual diagram illustrating an electro-optical sensor unit (30) according to one or more embodiments of the present disclosure. [Figure 3]FIG. 1 is a conceptual diagram illustrating a modulator maintenance unit (50) in accordance with one or more embodiments of the present disclosure. [Figure 4] 5A-5C are schematic diagrams illustrating the operation of detecting the flatness of the surface of a modulator (31) by a detection means (52) in accordance with one or more embodiments of the present disclosure. [Figure 5] FIG. 1 is a conceptual diagram illustrating an inspection system (100') according to one or more embodiments of the present disclosure. [Figure 6] 10 is a graph illustrating the results of detecting the surface condition of a modulator by a detection means of a modulator maintenance unit in accordance with one or more embodiments of the present disclosure. [Figure 7] 10 is a graph illustrating the results of detecting the surface condition of another modulator by a detection means of a modulator maintenance unit in accordance with one or more embodiments of the present disclosure. [Figure 8] FIG. 1 is a conceptual diagram illustrating a modulator maintenance unit (50') according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0024] Reference will now be made in detail to the disclosed subject matter, which is illustrated in the accompanying drawings. The present disclosure has been particularly shown and described with reference to certain embodiments and specific features thereof. The embodiments described herein should be considered illustrative and not limiting. It will be readily apparent to those skilled in the art that various changes and modifications in form and detail can be made therein without departing from the spirit and scope of the present disclosure.

[0025] An inspection system 100 according to one or more embodiments of the present disclosure will now be described in more detail with reference to FIGS.

[0026] FIG. 1 is a conceptual diagram illustrating an inspection system (100) according to one or more embodiments of the present disclosure.

[0027] The inspection system 100 depicted in Figure 1 can be configured to inspect electrical circuits using electro-optical sensor units (modulators). The inspection system 100 can be used to inspect electrical circuits, for example, but not limited to, flat panel display electrical circuits, and can be used to inspect any other suitable type of substrate-side electrical circuitry.

[0028] The inspection system 100 may include a chassis, such as the chassis 10 of an automated flat panel display inspection system, such as the ARRAY CHECKER™ system commercially available from Orbotech Ltd. Materials such as granite, polymer casting, steel, or carbon fiber may be used for the chassis 10 of the inspection system 100 to provide rigidity over a large area.

[0029] The inspection system 100 may include a chuck 20 for supporting a glass sheet (also known as a substrate or plate), particularly a glass sheet containing electrical circuitry to be tested. The chuck 20 supports the glass sheet (not shown) and provides a rigid reference plane for the glass sheet. For example, air may be blown across the entire surface of the chuck 20, creating an air cushion between the chuck 20 and the glass sheet. According to this embodiment, the glass sheet may be suspended on the air cushion and then aligned using a mechanical device such as a gripper, scrubber, or the like. After alignment, the air may be turned off and a vacuum applied to clamp the glass sheet into place for processing. Examples of materials for the chuck 20 include anodized aluminum, ceramics, glass, and / or metal.

[0030] The glass sheet can be moved onto the chuck 20 by a factory robot arm. The glass sheet supported by the chuck 20 can incorporate multiple electrical circuits for one or more flat panel displays. Typically, the electrical circuits on the glass sheet are identical to one another, but a single glass sheet can contain electrical circuits of different shapes and designs. For example, a glass sheet measuring 2m x 2m to 3m x 3m can be subdivided after inspection into multiple sections each containing a separate electrical circuit. Displays containing these subdivided electrical circuits can be used, for example, in televisions, telephones, and other small display applications. Each electrical circuit under test can include, for example, at least one array of uniformly spaced parallel conductors. The uniformly spaced conductors are typically spaced in a generally parallel configuration, but as can be appreciated, the uniformly spaced conductors can have any suitable geometric configuration. The at least one array can be one-dimensional or two-dimensional. Each conductor in the at least one array may be associated with at least one individual pixel in an electrical circuit within the flat panel display. For example, a two-dimensional array of individual pixels may be provided within the electrical circuit, and each pixel may be considered an individual conductor and electrically controlled by the circuit. Each of the electrical circuits may include a plurality of conductive, insulating, and semiconductor elements. Each pixel may be driven with an electrical signal such that the array of pixels corresponds to a one- or two-dimensional array of parallel conductors.

[0031] Although not specifically shown, the test system 100 may include voltage drivers that apply voltages to individual conductors in the electrical circuit currently under test, which is preferably accomplished through the use of shorting bars, for example, but may also be a two-dimensional array probing system.

[0032] As shown in FIG. 1 , electro-optic sensor units 30, such as one or more electro-optic sensor units including electro-optic modulators, can be mounted on a gantry 40 or other movable structure. The gantry 40 can be movably mounted on the chassis 10 to allow the electro-optic sensor units 30 to move up and down and laterally above the electrical circuitry. For example, to inspect the electrical circuitry on a glass sheet, the electro-optic sensor units 30 can be moved laterally over a portion of the glass sheet and then lowered to within a few tens of microns of the surface of the glass sheet. After inspection is complete, the electro-optic sensor units 30 can be lifted away from the surface of the glass sheet.

[0033] FIG. 2 is a conceptual diagram illustrating an electro-optical sensor unit (30) according to one or more embodiments of the present disclosure. The electro-optical sensor unit (30) can be configured to detect electrical defects in electrical circuits on the glass sheet. As shown in FIG. 2, the electro-optical sensor unit (30) can include a modulator (31). A drive signal can be applied to electrodes on the glass sheet to inspect the electrical circuits. A gap (32) between the glass sheet and the modulator (31) allows an electric field from each pixel electrode on the glass sheet on which the electrical circuits are formed to couple to the modulator (31), thereby generating a temporary visual representation of the glass sheet. This visual representation can be captured by a camera (33) for defect identification. After inspecting an area, the modulator (31) can be lifted and moved to another area on the glass sheet, and the process can be repeated. Through this step-and-repeat process, the electrical circuits can be inspected for defects. In one embodiment, the modulator 31 may include an LC material 31-1 and flat glass 31-2. However, the configuration of the electro-optical sensor unit 30 is not limited to that shown in Figure 2, and the electro-optical sensor unit may be configured in various forms to detect electrical defects on the glass sheet, such as a light source, a beam expander, a beam splitter, etc., to couple an electric field from each pixel electrode on the glass sheet to the modulator.

[0034] In one embodiment, the disclosed test system (100) employs a method known as "VOLTAGE IMAGING" (registered trademark), which utilizes a reflective liquid crystal-based modulator configured to measure the voltage on individual TFT array pixels. During TFT array testing, drive voltage patterns are applied to the TFT panel under test, and the resulting panel pixel voltages are measured by positioning the electro-optic modulator described above in close proximity (typically about 50 μm) to the TFT array under test and exposing the modulator to a high-voltage square wave voltage pattern. The amplitude of the voltage square wave pattern applied to the modulator can be varied depending on the test conditions. For example, the voltage square wave pattern applied to the modulator could have an amplitude of 300 V and a frequency of 60 Hz. Due to its proximity to the pixels of the TFT array under test to which the drive voltage is applied, the potential formed on the test system's electro-optic modulator forces a change in the field-dependent spatial orientation of the liquid crystals within the modulator, which in turn locally changes the optical transmittance of the liquid crystals above the modulator. In other words, the optical transmittance of a modulator is representative of the voltage on the array pixel nearby. To capture the changed modulator transmittance, the modulator is illuminated with a light pulse, and the light reflected by the modulator, supplied with the panel voltage, is imaged onto a Voltage Imaging Optical Subsystem (VIOS) camera, which captures and digitizes the resulting image.

[0035] 2, when inspecting electrical circuits, the modulator 31 can be held at a small gap 32 from the surface of the glass sheet on which the electrical circuits are mounted, as shown in FIG. 2. The modulator 31 is generally held above the glass sheet at a distance of about 30 μm to 50 μm. The distance between the modulator 31 and the glass sheet should be controlled to be as close as practical without causing side effects such as short circuits, heat transfer, or mechanical distortion due to stress.

[0036] However, because the glass sheet and modulator 31 are positioned side-by-side, any foreign matter (e.g., particles) present between the glass sheet and modulator 31 could damage the glass sheet and / or modulator 31 during the inspection process. To prevent this damage, conventionally, an operator would manually unload the modulator, place it in a specific position (e.g., the home position), and then clean the modulator by directly wiping its surface. However, this conventional method requires stopping the system during the inspection process to clean the modulator, reducing process efficiency. Furthermore, some particles and damage spots on the modulator surface that affect the inspection results can be very small, making it difficult for an operator to identify and remove these small particles or damage with the naked eye.

[0037] To address these issues, an inspection system 100 may be provided with a modulator maintenance unit 50 in accordance with an embodiment of the present disclosure, as shown in Figure 1. As shown in Figure 1, the modulator maintenance unit 50 may be located on the side of the chuck 20 that supports the glass sheet. However, the location of the modulator maintenance unit 50 is not limited thereto, and the modulator maintenance unit 50 may be located in any area of ​​the system 100 that is reachable from the modulator 31.

[0038] 3 is a conceptual diagram illustrating a modulator maintenance unit 50 according to one or more embodiments of the present disclosure. As shown in FIG. 3, the modulator maintenance unit 50 may include at least one of a cleaning means 51 for removing foreign matter on the surface of the modulator and a detection means 52 for detecting the flatness of the surface of the modulator.

[0039] According to one or more embodiments, the cleaning means 51 can include one or more air knives, as shown in FIG. 3. The modulator 31 can be positioned adjacent to these air knives, and air can be blown from the air knives toward the surface of the modulator 31 to remove particles from the surface of the modulator 31 before, after, or during the inspection of the glass sheet. Using an air knife as the cleaning means 51 can more efficiently remove foreign matter from the surface of the modulator 31 while minimizing damage to the surface of the modulator 31. While the cleaning means 51 is depicted in FIG. 3 as including an air knife, the cleaning means 51 is not limited thereto and can include one or more tools, such as wipers, hard brushes, soft brushes, cloths, etc., capable of removing liquid, solid, and / or gas phase particles from the surface of the modulator 31.

[0040] According to one or more embodiments, the modulator maintenance unit 50 of one or more embodiments of the present disclosure may further include a detection means 52 for detecting the flatness of the surface of the modulator 31, as shown in Figure 3. By detecting the flatness of the surface of the modulator using the detection means 52, it is possible to check whether there are foreign objects (particles) on the surface of the modulator 31 and / or whether there are any damaged areas on the surface of the modulator 31.

[0041] As shown in FIG. 3, the detection means 52 may include a laser sensor having a laser emitting unit 52-1 and a laser receiving unit 52-2. For example, the laser emitting unit 52-1 may emit a laser beam with a circular spot of approximately 1 mm. The modulator 31 may be positioned adjacent to the detection means 52 before, after, or during the glass sheet inspection operation, and the detection means 52 may detect the flatness of the modulator 31 located adjacent to the modulator 31. Using a laser sensor as the detection means 52 makes it possible to detect surface damage or particles on the surface of the modulator 31, which may be several microns to several tens of microns in size. While the detection means 52 is depicted in FIG. 3 as including a spot laser sensor, this is not limiting. The detection means 52 may include one or more tools, such as a CCD camera or a 3D camera, capable of detecting the flatness of the surface of the modulator 31.

[0042] FIG. 4 schematically illustrates the operation of detecting the flatness of the surface of the modulator 31 using the detector 52 according to one or more embodiments of the present disclosure. As shown in FIG. 4, the modulator 31 can be disposed between the laser emitting unit 52-1 and the laser receiving unit 52-2 of the detector 52, and the surface of the modulator 31 can be scanned by the detector 52 while the modulator 31 is moved laterally. Specifically, as shown in FIG. 4, the laser emitting unit 52-1 emits a laser beam parallel to the surface of the modulator 31 and perpendicular to the direction of movement of the modulator 31. By appropriately positioning the detector 52, the laser beam emitted from the laser emitting unit 52-1 can be made to partially overlap the surface of the modulator 31 as it is moving laterally. The laser receiving unit 52-2 of the detection means 52 can detect changes in laser light intensity due to lateral movement of the modulator 31, thereby detecting the flatness of the surface of the modulator 31. For example, a control unit included in the inspection system 100 can determine whether or not there are convex portions (due to foreign matter, etc.) or concave portions (due to surface damage, etc.) on the surface of the modulator 31 based on the changes in laser light intensity detected by the laser receiving unit 52-2. In other words, by scanning the surface of the modulator 31, it is possible to determine whether or not there are foreign matters on the surface of the modulator 31 and whether or not there is damage to the surface of the modulator 31. According to one embodiment, the inspection system 100 can be configured so that if the control unit determines that there is a foreign matter on the surface of the modulator 31, the cleaning means 51 removes the foreign matter from the surface of the modulator 31. According to one embodiment, the inspection system 100 can be configured to send an equipment abnormality signal to a main system or appropriate factory automation equipment if the control unit determines that there are protrusions and / or depressions on the surface of the modulator 31.

[0043] According to certain embodiments, both the cleaning means 51 and the detection means 52 can be operated when the modulator 31 is located next to the modulator maintenance unit 50, i.e., the cleaning means 51 can remove particles from the surface of the modulator 31, and the detection means 52 can detect the flatness of the modulator 31. In other words, when a modulator 31 configured to be movable laterally and / or vertically is positioned next to the modulator maintenance unit 50, the cleaning means 51 can remove particles from the surface of the modulator 31, and the detection means 52 can detect the surface condition of the modulator 31, substantially simultaneously. In some embodiments, the cleaning means 51 can be located closer to the modulator 31 than the detection means 52 along the direction of movement of the modulator 31, i.e., the detection operation by the detection means 52 can be performed after the removal operation by the cleaning means 51. In some embodiments, the detection means (52) may be located closer to the modulator (31) than the cleaning means (51) along the direction of movement of the modulator (31), i.e., the removal operation by the cleaning means (51) may be performed after the detection operation by the detection means (52).

[0044] In the above embodiment, both the cleaning means 51 and the detection means 52 are operational when the modulator 31 is located adjacent to the modulator maintenance unit 50, but this is not limiting, and only one of the cleaning means 51 and the detection means 52 may be configured to operate when the modulator 31 is located adjacent to the modulator maintenance unit 50. Furthermore, while Figure 3 depicts the modulator maintenance unit 50 as having both the cleaning means 51 and the detection means 52, this is not limiting, and the modulator maintenance unit 50 may have only one of the cleaning means 51 and the detection means 52.

[0045] 3, the modulator maintenance unit 50 according to one or more embodiments of the present disclosure may further include a cylinder 53 supporting the cleaning means 51 and the detection means 52. The cylinder 53 allows the cleaning means 51 and the detection means 52 to be adjusted vertically, thereby eliminating mechanical interference during operation of the inspection system.

[0046] 1 above, a modulator maintenance unit 50 according to one or more embodiments of the present disclosure can be positioned on one side of the chuck 20. Because the modulator maintenance unit 50 is positioned on one side of the chuck 20, the modulator 31 can be moved onto that side of the chuck 20 before, after, or during an inspection of a glass sheet supported by the chuck 20, and cleaning and / or inspection operations can be performed on the surface of the modulator 31 by the modulator maintenance unit 50. In some embodiments, the modulator maintenance unit 50 can be located at any point within the inspection system 100 that can reach the modulator 31 other than on the side of the chuck 20. In this case, the modulator 31 can be moved to position the modulator 31 adjacent to the modulator maintenance unit 50, which can then perform cleaning and / or inspection operations on the surface of the modulator 31 adjacent to the modulator maintenance unit 50. The frequency, number, and timing of operations of the modulator maintenance unit 50 can be controlled by an operator. In some embodiments, the modulator maintenance unit 50 can be controlled by a control unit included in the inspection system 100 to operate each time the modulator 31 is positioned adjacent to the modulator maintenance unit 50. In other embodiments, the modulator maintenance unit 50 can be controlled by a control unit included in the inspection system 100 to operate each time a glass sheet is replaced, after a predetermined number of glass sheets have been replaced, at predetermined time intervals, or before and / or after inspecting the glass sheets.

[0047] Although FIG. 1 depicts two modulator maintenance units 50 positioned on one side of the chuck 20, the number of modulator maintenance units 50 is not limited thereto, and the inspection system 100 may include one or more modulator maintenance units 50. According to certain embodiments, the inspection system 100 may include the same number of modulator maintenance units 50 as the number of modulators 31. In this case, cleaning and / or inspection of multiple modulators 31 can be performed simultaneously by multiple maintenance units 50, each corresponding to a respective one of the multiple modulators 31, thereby more efficiently performing the cleaning and / or inspection operations of the modulators 31. In some embodiments, cleaning and / or inspection of multiple modulators 31 may be performed sequentially by the same modulator maintenance unit 50.

[0048] 1 depicts the modulator maintenance unit 50 located on one side of the chuck 20 adjacent to the front of the inspection system 100 (i.e., the side where the glass sheet is loaded / unloaded), the location of the modulator maintenance unit 50 is not limited thereto, and the modulator maintenance unit 50 can be located at any point on each side of the chuck 20. In addition, multiple modulator maintenance units 50 can be located on multiple sides of the chuck 20.

[0049] Figure 5 is a conceptual diagram illustrating an inspection system 100' according to one or more embodiments of the present disclosure. The configuration of the inspection system 100' shown in Figure 5, excluding the location of the modulator maintenance unit 50, can be applied in the same manner as the inspection system shown in Figure 1, and therefore the same configuration will not be described again. Figure 5 does not depict the electro-optical sensor unit 30 and gantry 40 shown in Figure 1 in order to more clearly show the location of the modulator maintenance unit 50.

[0050] 5, unlike the inspection system 100 shown in FIG. 1, the modulator maintenance unit 50 can be located on one of the sides of the chuck 20 adjacent to the rear of the inspection system 100′. According to one embodiment, the electro-optical sensor unit 30 can be configured to start inspecting the electrical circuits from one of the sides of the chuck 20 adjacent to the rear of the inspection system 100′, and the modulator maintenance unit 50 can be located next to the inspection start position of the electro-optical sensor unit 30. In this case, cleaning and / or flatness detection of the surface of the modulator 31 can be automatically performed by the modulator maintenance unit 50 at the start of the inspection operation for the electrical circuits. Therefore, more efficient cleaning and / or detection of the modulator can be achieved without additional movement of the modulator 31 for cleaning and / or detection.

[0051] FIG. 6 is a graph showing the results of detecting the surface condition of a modulator using a detection means of a modulator maintenance unit according to an embodiment of the present disclosure. Specifically, FIG. 6 shows the results of scanning the surface of the modulator before and after cleaning using the spot laser sensor shown in FIG. 3 as the detection means. To clean the surface of the modulator, the air knife shown in FIG. 3 was used as the cleaning means. Furthermore, to scan the surface of the modulator, the modulator was moved laterally between the laser emitting unit and the laser receiving unit of the laser sensor shown in FIG. 3, and the change in laser intensity due to the movement of the modulator (i.e., over time) was detected by the laser receiving unit. The flatness of the surface of the modulator can be detected through the change in laser intensity over time. FIG. 6 depicts the detection results of the change in laser intensity before cleaning the surface of the modulator ("before cleaning") and after cleaning the surface of the modulator ("after cleaning"). As shown in the graph of FIG. 6, the modulator has an uneven surface, as can be seen in the graph showing the surface scan results before cleaning the modulator. Furthermore, the cleaning removed particles from the surface of the modulator, leaving the modulator with a flat (smooth) surface, as can be seen in the graph showing the surface scan results after cleaning the modulator.

[0052] Figure 7 is a graph showing the results of detecting the surface condition of another modulator using a detection means according to an embodiment of the present disclosure. Specifically, Figure 7 shows the results of scanning the surface of the modulator using the air knife shown in Figure 3 as the cleaning means and the spot laser sensor shown in Figure 3 as the detection means. As shown in the graph in Figure 7, the modulator after cleaning has a flatter surface condition in some areas than before cleaning, but still has an uneven surface condition in other areas. These detection results confirm that there is damage on the surface of the modulator that cannot be removed by cleaning.

[0053] FIG. 8 is a conceptual diagram illustrating a modulator maintenance unit 50′ according to one or more embodiments of the present disclosure. As shown in FIG. 8, the modulator maintenance unit 50′ may include a cleaning means 51′ for removing particles from the surface of the modulator 31, a detection means 52′ for detecting the surface condition of the modulator 31, and a suction means 54 for sucking particles removed from the surface of the modulator 31. For example, as shown in FIG. 8, the cleaning means 51′ may include two air knives arranged on both sides of the detection means 52′, and the air knives may be configured to eject air toward the surface of the modulator 31. By positioning the air ejection ports of the two air knives so that they face the area between the two air knives, particles removed from the surface of the modulator 31 can be collected in the area between the two air knives. In addition, by providing a suction means 54 for sucking up particles removed from the surface of the modulator 31 between the two air knives as shown in Figure 8, it is possible to prevent the surface of the modulator 31 from being recontaminated by particles removed from the surface of the modulator 31. Although Figure 8 illustrates the modulator maintenance unit 50' as having two cleaning means 51' and one suction means 54, the arrangement and number of the cleaning means 51' and the suction means 54 are not limited thereto, and one or more cleaning means and one or more suction means may be disposed in appropriate positions.

[0054] Each component of the inspection system according to one or more embodiments of the present disclosure can be controlled by a control unit. According to certain embodiments, one or more modulator maintenance units can be individually or collectively controlled by the control unit. Additionally, the modulator maintenance unit according to one or more embodiments of the present disclosure can include at least one of a cleaning means and a detection means, and the operation of the cleaning means and the detection means can be individually or collectively controlled by the control unit. According to certain embodiments of the present disclosure, an operator (user) can set the operating conditions of the modulator maintenance unit, such as the operating time point, the number of operating time points, the operating frequency, the operating cycle, the operating procedure, etc., and the operation of the modulator maintenance unit can be automatically controlled by the control unit based on the settings.

[0055] Information collected by an inspection system according to certain embodiments of the present disclosure can be subsequently processed by one or more processors running software. The software used in the inspection system of the present disclosure can be configured to receive and analyze the results of a modulator surface scan by a modulator maintenance unit and notify a user of the results. The software used in the inspection system can further be configured to analyze the results of a modulator surface scan to determine whether damage above a threshold (e.g., a predetermined number and / or size) has occurred on the modulator surface and, if so, to issue an alert to the user.

[0056] The subject matter described herein is sometimes depicted as having various components embedded within, or connected or coupled to, other components. It should be understood that these illustrated architectures are merely exemplary, and that in fact, many other architectures can be implemented to achieve the same functionality. Conceptually, if any arrangement of components achieves the same functionality, then that arrangement is substantially "associated" with one another to achieve the desired functionality. Thus, any two components herein that are combined to achieve a particular function can be considered to be "associated" with one another to achieve the desired functionality, regardless of the architecture or intervening components. Similarly, any two components so associated can also be considered to be "connected" or "coupled" to one another to achieve the desired functionality, and any two components that can be so associated can also be considered to be "combinable" with one another to achieve the desired functionality. Examples of "couplable" include, but are not limited to, physically interactable and / or physically interacting components, and / or wirelessly interactable and / or wirelessly interacting components, and / or logically interactable and / or logically interacting components.

[0057] The present disclosure and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes can be made in the form, construction and arrangement of the parts without departing from the disclosed subject matter or diminishing all of its essential advantages. The described form is merely illustrative, and it is the intent of the following claims to encompass and embrace all such modifications. It will further be understood that it is the appended claims which define the invention. [Explanation of symbols]

[0058] 100,100' inspection system, 10 chassis, 20 chuck, 30 electro-optical sensor unit, 31 modulator, 32 gap, 33 camera, 40 gantry, 50,50' modulator maintenance unit, 51,51' cleaning means, 52,52' detection means, 52-1 laser emitting unit, 52-2 laser receiving unit, 53 cylinder, 54 suction means.

Claims

1. 1. A system for testing an electrical circuit, comprising: a chuck configured to support the electrical circuit; a modulator movable above the chuck and positioned above the electrical circuits and configured to detect defects in the electrical circuits; a modulator maintenance unit including at least one of a cleaning means for removing foreign matter from the surface of the modulator and a detection means for detecting the flatness of the surface of the modulator; Equipped with the detecting means includes one or more laser sensors each having a laser emitting unit and a laser receiving unit; A system in which the modulator is movable and can be positioned next to the modulator maintenance unit.

2. 2. The system of claim 1, wherein the modulator is configured to be positioned next to the modulator maintenance unit i) before testing of the electrical circuits begins, ii) after testing of the electrical circuits is completed, or iii) during testing operations of the electrical circuits.

3. 10. The system of claim 1, wherein the cleaning means comprises one or more air knives.

4. 2. The system of claim 1, wherein the laser emitting unit is configured to emit laser light in a direction parallel to a surface of the modulator positioned between the laser emitting unit and the laser receiving unit, and the laser light emitted from the laser emitting unit partially overlaps the surface of the modulator.

5. 2. The system of claim 1, wherein the laser receiving unit is configured to detect changes in laser light intensity due to lateral movement of the modulator positioned between the laser emitting unit and the laser receiving unit.

6. 6. The system of claim 5, further comprising: A system comprising a control unit that determines whether or not at least one of a convex portion and a concave portion exists on the surface of the modulator based on a change in the laser light intensity detected by the laser receiving unit.

7. 7. The system of claim 6, wherein the cleaning means removes foreign matter from the surface of the modulator when the control unit determines that a protrusion exists on the surface of the modulator.

8. 7. The system of claim 6, wherein the control unit generates an abnormality signal when the control unit determines that at least one of a protrusion and a recess exists on the surface of the modulator.

9. 2. The system of claim 1, wherein the modulator maintenance unit comprises the cleaning means and the detection means, and the modulator maintenance unit is configured to simultaneously perform a cleaning operation by the cleaning means and a detection operation by the detection means when the modulator is positioned adjacent to the modulator maintenance unit.

10. 2. The system of claim 1, wherein the modulator maintenance unit comprises the cleaning means and suction means for sucking foreign matter removed from the surface of the modulator by the cleaning means.

11. 11. The system of claim 10, wherein the modulator maintenance unit comprises two cleaning means, and the suction means is located between the two cleaning means.

12. 10. The system of claim 1, wherein the modulator maintenance unit is disposed on a side of the chuck.

13. 2. The system of claim 1, wherein the modulator maintenance unit is positioned on one side of the chuck, the side being the side of the chuck adjacent to the front of the inspection system.

14. 2. The system of claim 1, wherein the modulator maintenance unit is positioned on one side of the chuck, the side being the side of the chuck adjacent to the rear of the inspection system.

15. 2. The system of claim 1, wherein the modulator maintenance unit is positioned on one side of the chuck, the side being adjacent one of the sides of the chuck to a point where the modulator begins testing the electrical circuit.

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