Method for determining the X and Y positions of surface particles

Abstract

The present disclosure provides a system including a modulator, a laser source, a reflector, a laser sensor, and a processor. The modulator is movable in a first direction. The laser source is configured to emit laser light in a direction parallel to a surface of the modulator. The reflector is configured to redirect the laser light. The laser sensor is configured to detect a first change in intensity when a particle on the surface of the modulator passes through the laser light emitted by the laser source. The laser sensor is further configured to detect a second change in intensity when the particle on the surface of the modulator passes through the laser light redirected by at least one reflector. The processor is configured to determine an X-Y position of the particle based on the first change in intensity and the second change in intensity.

Description

Technical Field

[0001] The present disclosure relates to inspection processes, and more particularly, to a process for detecting surface particles on an inspection tool. Background Art

[0002] An exemplary inspection process uses a modulator to detect defects in circuits on a glass panel. For example, the modulator can be moved over a portion of a glass panel and lowered to within tens of microns of the surface of the glass panel. When a drive signal is applied to the electrodes of the glass panel, the electric field from the glass panel produces a temporarily visible display on the modulator, which can be captured by a camera to inspect for defects. However, since the glass panel and the modulator are positioned adjacent to each other during inspection, foreign matter (e.g., particles) that may be present between the glass panel and the modulator during the inspection operation may cause damage. Particles may also reduce the accuracy of the inspection process.

[0003] Currently, methods for cleaning modulators are open ended, meaning that the modulator surface may be cleaned periodically during the inspection process, but there is no confirmation that the foreign material has been removed from the modulator. Additionally, existing methods for detecting foreign material on the modulator surface are unable to locate the particle to confirm its removal from the system or to diagnose the problem.

[0004] Therefore, a method for determining the X and Y positions of surface particles is needed. Summary of the invention

[0005] Embodiments of the present disclosure provide a system, which includes a modulator, a laser source, at least one reflector, a laser sensor, and a processor. The modulator may be configured to detect defects in a circuit. The modulator may be movable in a first direction. The modulator may be movable at a constant speed. The laser source may be positioned adjacent to a first side of the modulator. The laser source may be configured to emit laser light toward a second side of the modulator in a direction parallel to the modulator surface and at a first angle relative to the first direction. The laser light may overlap partially with the surface of the modulator. The at least one reflector may be positioned adjacent to the second side opposite to the first side of the modulator. The at least one reflector may be configured to redirect the laser light toward the first side of the modulator at a second angle relative to the first direction. The laser sensor may be positioned adjacent to the first side of the modulator. The laser sensor may be configured to detect a first change in the intensity of the laser light received from the laser source when a particle on the modulator surface passes through the laser light emitted by the laser source, and to detect a second change in the intensity of the laser light received from the laser source redirected by the at least one reflector when the particle on the modulator surface passes through the laser light redirected by the at least one reflector. The processor may be configured to determine an XY position of the particle based on the first change in intensity and the second change in intensity.

[0006] According to an embodiment of the present disclosure, the system may further include an air knife configured to remove the particle from the modulator surface after determining the XY position of the particle. The air knife may be positioned between the laser source and the laser sensor, or may be positioned downstream of the laser source and the laser sensor.

[0007] According to an embodiment of the present disclosure, the at least one reflector may include a pair of reflectors positioned at symmetrical angles with respect to the first direction.

[0008] According to an embodiment of the present disclosure, the at least one reflector may include a reflector positioned parallel to the first direction.

[0009] According to an embodiment of the present disclosure, the XY position of the particle may be determined relative to an origin defined by a corner of the modulator that first passes through the laser light emitted from the laser source.

[0010] According to an embodiment of the present disclosure, the XY position of the particle can be determined based on a first distance between the laser source and the origin determined at a time corresponding to the first change in intensity and a second distance between the laser sensor and the origin determined at a time corresponding to the second change in intensity.

[0011] According to an embodiment of the present disclosure, the XY position of the particle may be determined based on a difference between a time corresponding to the first change in intensity and a time corresponding to the second change in intensity.

[0012] According to an embodiment of the present disclosure, the XY position of the particle may be determined based on the first angle and / or the second angle. The first angle and the second angle may be between 0 degrees and 90 degrees.

[0013] Another embodiment of the present disclosure provides a method, which includes: moving a modulator in a first direction, the modulator being configured to detect defects in a circuit; emitting a laser toward a second side of the modulator in a direction parallel to a surface of the modulator and at a first angle relative to the first direction by a laser source positioned adjacent to a first side of the modulator, and the laser partially overlaps the surface of the modulator; redirecting the laser toward the first side of the modulator at a second angle relative to the first direction by at least one reflector positioned adjacent to the second side opposite to the first side of the modulator; when a particle on the surface of the modulator passes through the laser emitted by the laser source, detecting a first change in intensity of the laser received from the laser source by a laser sensor positioned adjacent to the first side of the modulator; when the particle on the surface of the modulator passes through the laser redirected by the at least one reflector, detecting a second change in intensity of the laser received from the laser source redirected by the at least one reflector by the laser sensor; and determining an XY position of the particle by a processor based on the first change in intensity and the second change in intensity.

[0014] According to an embodiment of the present disclosure, the method may further include passing the modulator through an air knife to remove the particles from the modulator surface. The air knife may be positioned between the laser source and the laser sensor, and the air knife may be configured to be turned off when the modulator is moved in the first direction. The method may further include moving the modulator in a second direction, the second direction being opposite to the first direction. The air knife may be configured to be turned on when the modulator is moved in the second direction.

[0015] According to an embodiment of the present disclosure, the air knife may be positioned downstream of the laser source and the laser sensor, and the air knife may be configured to turn on when the modulator is moved in the first direction.

[0016] According to an embodiment of the present disclosure, the method may further include defining a corner of the modulator that first passes through the laser light emitted from the laser source as an origin. The XY position of the particle may be determined relative to the origin.

[0017] According to an embodiment of the present disclosure, the processor determines the XY position of the particle based on the first change in intensity and the second change in intensity, which may include: determining a first distance between the laser source and the origin at a time corresponding to the first change in intensity; determining a second distance between the laser sensor and the origin at a time corresponding to the second change in intensity; and determining the XY position of the particle based on the first distance and the second distance.

[0018] According to an embodiment of the present disclosure, determining the XY position of the particle by the processor based on the first change in intensity and the second change in intensity may include: determining the distance traveled by the modulator in the first direction between a time corresponding to the first change in intensity and a time corresponding to the second change in intensity; and determining the XY position of the particle based on the distance traveled by the modulator in the first direction between the time corresponding to the first change in intensity and the time corresponding to the second change in intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] For a more complete understanding of the nature and purpose of the present disclosure, reference should be made to the following detailed description in conjunction with the accompanying drawings, in which:

[0020] Figure 1A 1 through 2 illustrate a modulator of the system of the present disclosure traversing in a first direction in a first configuration;

[0021] Figure 1G to H illustrate a modulator traversing the system in a second direction in a first configuration;

[0022] Figure 2A H illustrate a modulator and corresponding output signal diagram traversing the system of the present disclosure in a first direction in a second configuration;

[0023] Figure 3A to B illustrate a modulator traversing the system in a second direction in a second configuration;

[0024] Figure 4 is a flow chart of a method according to an embodiment of the present disclosure;

[0025] Figure 5 is a flowchart of a method according to another embodiment of the present disclosure; and

[0026] Figure 6 is a flowchart of a method according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] Although the claimed subject matter will be described in terms of certain embodiments, other embodiments, including embodiments that do not provide all of the advantages and features set forth herein, are also within the scope of the present disclosure. Various structural, logical, process step, and electronic changes may be made without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure is defined solely by reference to the appended claims.

[0028] An embodiment of the present disclosure provides a system 100 . Figure 1A H shows the system 100 in a first configuration, and Figure 2A 3A to H and 3A to B show system 100 in a second configuration. The first and second configurations of system 100 are referred to interchangeably herein. System 100 may be part of a system for inspecting circuits in, for example, glass display panels. Liquid crystal display (LCD) panels incorporate liquid crystals that exhibit electric field-dependent light modulation properties. They are often used to display images and other information in a variety of devices, from fax machines, laptop screens to large screen, high-definition televisions. Active matrix LCD panels are complex layered structures composed of several functional layers: polarizing films; TFT glass substrates incorporating thin film transistors, storage capacitors, pixel electrodes, and interconnect wiring; color filter glass substrates incorporating black matrices and color filter arrays and transparent common electrodes; oriented films made of polyimide; and actual liquid crystal materials incorporating plastic / glass spacers to maintain appropriate LCD cell thickness. System 100 may be used to inspect other types of glass display panels (e.g., OLED, micro-LED, etc.) or other types of circuits disposed on substrates.

[0029] refer to Figure 1A and 2A, the system 100 may include a modulator 110. The modulator 110 may be configured to detect defects in a circuit, such as defects in a glass panel. For example, the modulator 110 may be moved over a portion of a glass panel and lowered to within tens of microns of the surface of the glass panel. When a drive signal is applied to an electrode of the glass panel, an electric field from the glass panel may produce a temporarily visible display on a surface 113 of the modulator 110, which may be captured by a camera to inspect for defects. The modulator 110 may be moved in the X, Y, and Z directions by a gantry (not shown). The gantry may be configured to move the modulator at a constant speed v. For example, the modulator 110 may be moved at a speed v of 1 m / s. Other speeds (faster or slower) may be possible depending on system requirements. As further described herein, the modulator 110 may be moved to perform an inspection and cleaning process on the modulator 110. When performing the inspection and cleaning process, the modulator 110 may be moved in a first direction. The first direction may correspond to a -Y direction. The modulator 110 may be of various sizes and shapes. For example, the modulator 110 may have a square shape with each side less than 200 mm. In a specific example, the modulator 110 may be 131 mm by 131 mm. Larger sizes of the modulator 110 (eg, 500 mm) are possible. Other sizes and shapes of the modulator 110 are possible.

[0030] Although the present disclosure is described with respect to the modulator 110, the system 100 may also be used for particle detection on a wafer that may be circular and between 100 mm and 300 mm in diameter, or on plain glass that may be as large as 3 m by 3 m.

[0031] The system 100 may further include a laser source 120. The laser source 120 may be positioned adjacent to the first side 111 of the modulator 110. For example, the laser source 120 may be disposed on the first support structure 101 of the system 100. When performing the inspection and cleaning process, the modulator 110 may be moved in a first direction so that the first side 111 of the modulator 110 is adjacent to and parallel to the first support structure 101. The laser source 120 may be configured to emit a laser 122 toward the second side 112 of the modulator 110 in a direction parallel to the surface 113 of the modulator 110 and at a first angle α relative to the first direction. For example, the laser 122 may be a circular spot laser having a diameter of at least 100 μm, but other laser diameters are possible. In a particular embodiment, the laser diameter may be approximately 1 mm. The laser 122 may be directed parallel across the surface of the modulator 110 and may at least partially overlap the surface 113 of the modulator 110. The laser light 122 may be directed across the surface of the modulator 110 at a converging or diverging angle as long as the laser light 122 at least partially overlaps the surface 113 of the modulator 110 along the entire path.

[0032] The first angle α may be 0 to 90 degrees. For example, the first angle α may be greater than 0 degrees and less than 90 degrees, and / or between 10 degrees and 70 degrees. In a specific embodiment, the first angle α may be 20 degrees.

[0033] The system 100 may further include at least one reflector 130. The at least one reflector 130 may be positioned adjacent to a second side 112 of the modulator 110 opposite to the first side 111. For example, the at least one reflector 130 may be disposed on a second support structure 102 of the system 100. When performing the inspection and cleaning process, the modulator 110 may be moved in the first direction so that the second side 112 of the modulator 110 is adjacent to and parallel to the second support structure 102. In this manner, when performing the inspection and cleaning process, the modulator 110 may be moved in the first direction between the first support structure 101 and the second support structure 102. The at least one reflector 130 may be configured to redirect the laser light 122 toward the first side 111 of the modulator 110 at a second angle β relative to the first direction. As used herein, the laser light 122 redirected by the at least one reflector may be described as redirected laser light 124.

[0034] The second angle β may be 0 to 90 degrees. For example, the second angle β may be greater than 0 and less than 90 degrees, and / or between 10 and 70 degrees. In a particular embodiment, the second angle β may be 20 degrees. The first angle α and the second angle β may be the same or different angles. Although the first angle α and the second angle β are shown in the figure as angles relative to the vertical direction (i.e., the X direction), it should be understood that some calculations may use the supplementary angles of the first angle α and the second angle β (i.e., 90-α or 90-β) to use angles relative to the horizontal direction (i.e., the Y direction). In this way, the values ​​of the first angle α and the second angle β may depend on the definition of the coordinate system of the system 100.

[0035] In an embodiment, the at least one reflector 130 may include a pair of reflectors. For example, the at least one reflector 130 may include a first reflector 131 and a second reflector 132. Figure 1A H. Laser light 122 from the laser source 120 may be redirected from the first reflector 131 to the second reflector 132. The portion of the laser light redirected from the first reflector 131 and incident on the second reflector 132 may be referred to as intermediate laser light 123. The first reflector 131 and the second reflector 132 may be separated by a distance greater than or equal to the length of the modulator 110. In this manner, the modulator 110 may completely pass through the laser light 122 before passing through the redirected laser light 124. Different distances (e.g., smaller or larger) may be used based on system requirements.

[0036] The first reflector 131 and the second reflector 132 may be positioned at symmetrical angles relative to the first direction. In this way, the first angle α of the laser light 122 incident on the first reflector 131 and the second angle β of the redirected laser light 124 from the second reflector 132 may be equal. For example, the first reflector 131 and the second reflector 132 may be positioned so that the intermediate laser light 123 is parallel to the first direction. In this way, the width between the first support structure 101 and the second support structure 102 may be minimized, and / or the intermediate laser light 123 may not pass through the surface 113 of the modulator 110. In other designs, the first reflector 131 and the second reflector 132 may be positioned at different angles relative to the first direction. In this way, the first angle α of the laser light 122 incident on the first reflector 131 and the second angle β of the redirected laser light 124 from the second reflector 132 may be different, and the intermediate laser light 123 may be angled relative to the first direction. The different angles of the first angle α and the second angle β may be determined based on system requirements.

[0037] The at least one reflector 130 may include more than two reflectors and may be alternately disposed on the first support structure 101 and the second support structure 102 to redirect the laser light 122 additional multiple times.

[0038] In another embodiment, the at least one reflector 130 may include a reflector such as Figure 2A To H and Figure 3A 1. The reflector 130 may be disposed on the second support structure 102. The reflector 130 may be positioned parallel to the first direction. In this way, the first angle α of the laser 122 incident on the reflector 130 and the second angle β of the redirected laser 124 may be equal. In this design, the reflector 130 may be simply set up and aligned with other components of the system 100. In other designs, the reflector 130 may be positioned at an angle relative to the first direction so that the first angle α and the second angle β may be different relative to the first direction. The different angles of the first angle α and the second angle β may be determined based on system requirements. In either case, using one reflector 130 may reduce space requirements compared to using more than one reflector 130.

[0039] The system 100 may further include a laser sensor 140. The laser sensor 140 may be positioned adjacent to the first side 111 of the modulator 110. For example, the laser sensor 140 may be disposed on the first support structure 101 of the system 110. The laser sensor 140 may be located downstream of the laser source 120 in the first direction. The laser sensor 140 may generate an output signal 145 based on the laser light 122 received from the laser source 120. A graph showing the output signal 145 is shown in FIG. Figure 2B , 2D, 2F, and 2H. A constant intensity in the output signal 145 generated by the laser sensor 140 may indicate that the surface 113 of the modulator is flat (e.g., free of defects or foreign matter). A change in intensity (i.e., a spike) in the output signal 145 generated by the laser sensor 140 may indicate a defect or foreign matter (e.g., a particle 115) on the surface 113 of the modulator 110. When the change in intensity is greater than a preset threshold, a defect or foreign matter may be indicated. The output signal 145 may be the opposite of the measured power, meaning that a rising spike indicates a short-term interruption along the laser path at that moment. Alternatively, the laser sensor 140 may be configured to generate a positive-going output signal 145 with appropriate changes to the system logic.

[0040] When the modulator 110 is close to the panel, particles 115 on the modulator 110 may cause damage. These particles may be 20 μm to 30 μm in diameter or larger.

[0041] When the particle 115 on the surface 113 of the modulator 110 passes through the laser light 122 emitted by the laser source 120, the laser sensor 140 may be configured to detect a first change 141 (eg, Figure 1C , 2C 2D). In other words, when the modulator 110 moves in the first direction, the modulator 110 may pass through the laser light 122 emitted by the laser source 120. The particles 115 on the surface 113 of the modulator 110 may cause a first change 141 in intensity in the output signal 145.

[0042] The laser sensor 140 may be further configured to detect a second change 142 (e.g., a second change in intensity 144) in the laser light 124 received from the laser source 120 and redirected by the at least one reflector 130 when the particle 115 on the surface 113 of the modulator 110 passes through the laser light 124 redirected by the at least one reflector 130. Figure 1F , 2E 2F). In other words, when the modulator 110 moves in the first direction, the modulator 110 may further pass through the redirected laser light 124. The particles 115 on the surface 113 of the modulator 110 may cause a second change 142 in intensity in the output signal 145.

[0043] The system 100 may further include a processor 150. The processor 150 may include a microprocessor, a microcontroller, or other devices.

[0044] The processor 150 may be coupled to the components of the system 100 in any suitable manner (e.g., via one or more transmission media that may include wired and / or wireless transmission media) such that the processor 150 may receive the output. The processor 150 may be configured to use the output to perform a number of functions. The inspection tool may receive instructions or other information from the processor 150. The processor 150 may optionally be in electronic communication with another inspection tool, metrology tool, or retest tool (not illustrated) to receive additional information or send instructions.

[0045] Processor 150 may be part of a variety of systems, including a personal computer system, an image computer, a mainframe computer system, a workstation, a network appliance, an Internet appliance, or other devices. The subsystem or system may also include any suitable processor known in the art, such as a parallel processor. In addition, the subsystem or system may include a platform with high-speed processing and software, as a stand-alone tool or a networked tool.

[0046] Processor 150 may be disposed in or as part of system 100 or another device. In an example, processor 150 may be part of an independent control unit, or in a centralized quality control unit. Multiple processors 150 may be used, defining multiple subsystems of system 100.

[0047] The processor 150 may be implemented in practice by any combination of hardware, software, and firmware. In addition, its functions as described herein may be performed by one unit, or divided between different components, each of which may in turn be implemented by any combination of hardware, software, and firmware. Program codes or instructions for the processor 150 to implement various methods and functions may be stored in a readable storage medium such as a memory.

[0048] The processor 150 may be configured according to any of the embodiments described herein.The processor 150 may also be configured to perform other functions or additional steps using the output of the system 100 or using images or data from other sources.

[0049] The processor 150 may be communicatively coupled to any of the various components or subsystems of the system 100 in any manner known in the art. In addition, the processor 150 may be configured to receive and / or obtain data or information from other systems via a transmission medium that may include wired and / or wireless portions. In this manner, the transmission medium may be used as a data link between the processor 150 and other subsystems of the system 100 or systems external to the system 100. The various steps, functions, and / or operations of the system 100 and the methods disclosed herein are performed by one or more of: electronic circuits, logic gates, multiplexers, programmable logic devices, ASICs, analog or digital controls / switches, microcontrollers, or computing systems. The above description should not be construed as limiting the present disclosure, but is merely illustrative.

[0050] The processor 150 may communicate with the laser sensor 140. For example, the processor 150 may be configured to receive an output signal 145 from the laser sensor 140. Thus, the processor 150 may receive a first change in intensity 141 and a second change in intensity 142 from the laser sensor 140. The processor 150 may be configured to determine an XY position of the particle 115 on the modulator 110 based on the first change in intensity 141 and the second change in intensity 142 according to any of the calculation methods disclosed herein. The XY position of the particle 115 may be determined relative to an origin O. The origin O may be defined by a corner of the modulator 110 that first passes through the laser light 122 emitted from the laser source 120 (e.g., Figure 1B and 2A 145). Using the output signal 145 and the velocity v, the distance of the laser source 120 and the laser sensor 140 from the origin O can be determined. For example, with a velocity v of 1 m / s, the distance of the laser source 120 from the origin O can change by 1 mm every 1 ms. Therefore, the length of the modulator 110 (in mm) can correspond to the time period (in ms) in the output signal 145, and the distance of the laser source 120 from the origin O can be determined at each moment in the output signal 145. Alternatively, a position encoder can be used to track the position of the modulator 110, so that the processor 150 can query the position of the modulator 110 at the time corresponding to the first change in intensity 141 and the second change in intensity to determine the relative distance from the origin O. In this way, the processor 150 can correlate the time and position information from the position encoder with the time and laser power information in the output signal 145 from the laser sensor 140. By further using the first angle α and / or the second angle β, the XY position of the particle 115 can be determined using one of the following methods.

[0051] In an embodiment, the XY position of the particle 115 may be based on the time T corresponding to the first change 141 in intensity. 1 The first distance D between the laser source 120 and the origin O is determined 1 and at time T corresponding to the second change 142 of intensity 2 The second distance D between the laser sensor 140 and the origin O is determined 2 For example, the sensor output 145 may be determined at time T when the laser 122 is at the origin O. 0 Start. Time T 1 is the time T 0 The time point after that. Time T 2 is the time point at which the redirected laser 124 is behind the origin O. The first distance D 1 and the second distance D 2 It can be obtained by multiplying the speed v by the time T1 and time T 2 can be determined directly from the position encoder. 1 , the particle 115 may be along a line L defined by the laser light 122 from the laser source 120 1 Found somewhere, and at time T 2 , the particle may be along a line L defined by the redirected laser light 124 received by the laser sensor 140 2 Therefore, the XY position of particle 115 can be determined by line L 1 and L 2 This method is used in Figure 1A This is most evident in the configuration of system 100 shown in FIG. 1 , but it is also applicable to Figure 2A To the configuration of system 100 in H.

[0052] Line L 1 and L 2 The intersection of the two can be determined by defining a line L with a slope-intercept y=mx+b. 1 and L 2 is determined by where m is the slope of the line and b is the y-intercept. Using the first angle α and the second angle β, the line L 1 and L 2 The slopes of can be equal to -tanα and tanβ respectively. Depending on the definition of the X and Y directions, the line L 1 and L 2 The slopes of L can be equal to tan(90-α) and -tan(90-β) or other values. Based on the position of the origin O, the line L 1 and L 2 The y-intercept of can be equal to the first distance D 1 and the second distance D 2 Therefore, line L 1 and L 2 Can be defined as y = -tanαx + D 1 and y = tan βx + D 2 Using these functions, the XY position of particle 115 can be determined algebraically.

[0053] In an example, the modulator 110 may have a velocity v of 1 m / s, the first angle α may be 20°, the second angle β may be 20°, and the time T 1 can be 77ms, and time T 2 It can be 15ms. The first distance D 1 It can be calculated as 77mm, and the second distance D 2 It can be calculated as 15mm. Therefore, line L 1 and L 2They can be defined as y=-tan20x+77 and y=tan20x+15 respectively. The XY position of particle 115 can be approximately calculated as (86 mm, 46 mm) as follows:

[0054] -tan 20x+77=tan 20x+15

[0055] -0.36x+77=0.36x+15

[0056] 0.72x=62

[0057] x=86mm

[0058] y=tan 20(86)+15

[0059] y=46mm

[0060] In another embodiment, the XY position of the particle 115 can be based on the time T corresponding to the first change 141 of the intensity. 1 and the time T corresponding to the second change 142 of the intensity 2 For example, the sensor output 145 may be determined at the time T when the laser 122 is at the origin O. 0 Start, and time T 1 and time T 2 is the time T 0 Using the velocity v, it can be determined that the modulator 110 is at time T 1 With time T 2 The distance B traveled in the first direction between the particles 115 and the modulator. The distance B can also be determined directly from the position encoder. Using the distance B and the width W of the modulator, the distance A of the reflector 130 from the second side 112 of the modulator, the first angle α, and the second angle β, the XY position of the particle 115 can be determined using the following equation:

[0061] B=(T 2 -T 1 )v

[0062]

[0063] x=A+WC

[0064] y=T 1 vX tanα

[0065] It will be appreciated that the above equations may differ depending on the definitions of the X and Y directions and may require the use of the supplementary angles of the first angle α and the second angle β. Figure 2A This is most evident in the configuration of system 100 shown in FIG. 1 , but it is also applicable to Figure 1A To the configuration of system 100 shown in H.

[0066] In an example, the modulator 110 may have a width W of 131 mm and a speed v of 1 m / s, the reflector 130 may be disposed at a distance A of 10 mm from the second side 112 of the modulator 110, the first angle α may be 20°, the second angle β may be 20°, and the time T 1 can be 77ms, and time T 2 The XY position of particle 115 can be approximately calculated as (86 mm, 46 mm) as follows:

[0067] B=(T 2 -T 1 )v=(117-77)(1)=40mm

[0068]

[0069] x=A+WC=10+131-55=861mm

[0070] y=T 1 vX tanα=(77)(1)-(86)tan 20=46mm

[0071] Reference Figure 1A and 2A , the system 100 may further include an air knife 160. The air knife 160 may be configured to remove particles 115 from the surface 113 of the modulator 110. For example, air may be ejected from the air knife 160 toward the surface 113 of the modulator 110 so as to remove foreign matter from the surface 113 of the modulator 110. Using the air knife 160, foreign matter may be effectively removed from the surface 113 of the modulator 110 while minimizing damage to the surface 113 of the modulator 110. Although the air knife 160 is described herein as being used to clean the surface 113 of the modulator 110, other tools (e.g., scrapers, hard brushes, soft brushes, cloths, etc.) capable of removing liquid, solid, and / or gaseous particles from the surface 113 of the modulator 110 may be used.

[0072] The air knife 160 may be configured to, after determining the XY position of the particle 115 (i.e., after Figure 1G and 2G After that, the particles 115 are removed from the surface 113 of the modulator 110. In this way, the system 100 can track the XY position of the particles to diagnose system-level problems and / or use a second inspection process (i.e., inspection, cleaning, inspection) to confirm that the cleaning process has removed the particles 115. In the second inspection process (i.e., after Figure 3B Detection of particles 115 thereafter may indicate a problem with the air knife 160 or a defect on the surface 113 of the modulator 110 .

[0073] The air knife 160 can be disposed on the first support structure 101 and the second support structure 102 of the system 100. For example, the air knife 160 can extend from the first support structure 101 to the second support structure 102. In this manner, the modulator 110 can pass under the air knife 160 when moving between the first support structure 101 and the second structure 102 in the first direction.

[0074] exist Figure 1A In the embodiment shown in FIG. 1A , the air knife 160 can be positioned between the laser source 120 and the laser sensor 140. For example, the air knife 160 can be disposed on the first support structure 101 and the second support structure 102 between the laser source 120 and the laser sensor 140. In this manner, the modulator 110 can pass under the air knife 160 after passing through the laser 122 but before passing through the redirected laser 124, as shown in FIG. Figure 1E 100 within the overall inspection system. However, to avoid removing the particle 115 from the surface 113 of the modulator 110 before the XY position of the particle 115 is determined, the air knife 160 can be set to an off state. After the XY position of the particle 115 is determined, the air knife 160 can be set to an on state to remove the particle 115 from the surface 113 of the modulator 110, as shown in FIG. Figure 1G and 1H The modulator 110 may be moved in a second direction opposite to the first direction in order to pass under the air knife 160 after the XY position of the particle 115 is determined.

[0075] exist Figure 2A In the embodiments shown in 3A to 3B, the air knife 160 can be positioned downstream of the laser source 120 and the laser sensor 140. For example, the air knife 160 can be disposed on the first support structure 101 and the second support structure 102 downstream of the laser source 120 and the laser sensor 140. In this way, the modulator 110 can pass under the air knife 160 after passing through the laser 122 and the redirected laser 124, as shown in FIG. Figure 3A Thus, before determining the XY position of the particle 115, the modulator 110 may not pass under the air knife 160, as shown in FIG. Figure 2G This design may not require changing the direction of movement of the modulator 110 and / or switching the on and off states of the air knife 160 when performing the cleaning process to prevent the particle 115 from being removed before the XY position of the particle 115 is determined.

[0076] Based on space requirements, the air knife 160 may be positioned elsewhere in the system 100. The air knife 160 may also be positioned so that the modulator 110 may be moved in directions other than the first direction and / or the second direction to pass under the air knife 160.

[0077] With the disclosed system 100, the output signal 145 of the laser light 122 reflected by the mirror 130 can be used to determine the XY position of the particle 115 on the surface 113 of the modulator 110. By locating the particle 115, the cleaning process can be closed-loop, where feedback is provided to the system 100 to confirm effective cleaning of the modulator 110 and / or to diagnose system-level problems.

[0078] Although the present disclosure is described with reference to a single particle 115 on the surface 113 of the modulator 110, the system 100 can be used in the case of multiple particles 115. For example, after determining the XY position of the particle 115 on the surface 113 of the modulator 110 and passing the modulator 110 under the air knife 160, the detection process can be performed again. If additional particles 115 are detected, the modulator 110 can be passed under the air knife 160 again, and the detection process can be repeated until the surface 113 of the modulator 110 is confirmed to be free of particles 115. The system 100 can also include multiple modulators 110, which can be individually passed through the laser 122 to detect surface particles, and passed under the air knife 160 to remove surface particles. By determining the XY position of a particle on each of the multiple modulators 110, system-level problems can be diagnosed, where there is a correlation between the position of the particles on each of the modulators.

[0079] Another embodiment of the present disclosure provides a method 200. Figure 4 As shown in FIG. 2 , method 200 may include the following steps.

[0080] At step 210, a modulator is moved in a first direction. The modulator may be configured to detect defects in a circuit. The modulator may be the modulator 110 described above. Figure 1A To F and Figure 2A , 2C , 2E and 2G respectively, the modulator can be seen moving in the first direction.

[0081] At step 220, a laser source positioned adjacent to a first side of the modulator emits laser light in a direction parallel to a surface of the modulator and at a first angle relative to the first direction toward a second side of the modulator. The laser light may partially overlap a surface of the modulator.

[0082] At step 230, at least one mirror positioned adjacent a second side of the modulator opposite the first side redirects the laser light toward the first side of the modulator at a second angle relative to the first direction.

[0083] At step 240, a laser sensor positioned adjacent to a first side of the modulator detects a first change in intensity of laser light received from the laser source when a particle on the modulator surface passes through laser light emitted by the laser source. Figure 1C and Figure 2CIn the image, particles on the modulator surface can be seen passing through laser light emitted by the laser source.

[0084] At step 250, the laser sensor detects a second change in the intensity of laser light received from the laser source as the particles on the modulator surface pass through the laser light redirected by the at least one mirror. Figure 1F and Figure 2E In the image, particles on the modulator surface can be seen passing through laser light that is redirected by at least one mirror.

[0085] At step 260, the processor determines the XY position of the particle based on the first change in intensity and the second change in intensity. For example, the processor may receive an output signal from a laser sensor and may determine the XY position of the particle based on the timing of the first change in intensity and the second change in intensity in the output signal.

[0086] According to an embodiment of the present disclosure, step 260 may include the following steps (eg Figure 5 (shown in the).

[0087] At step 261, the corner of the modulator that first passes through the laser light emitted from the laser source is defined as the origin. The XY position of the particle can be determined relative to the origin.

[0088] In step 262, a first distance between the laser source and the origin is determined at a time corresponding to a first change in intensity. The first distance is Figure 1C Visible in.

[0089] In step 263, a second distance between the laser sensor and the origin is determined at a time corresponding to the second change in intensity. Figure 1F Visible in.

[0090] At step 264, the XY position of the particle is determined based on the first distance and the second distance. For example, the first distance and the second distance may be used to define two lines that intersect at the XY position of the particle. The intersection point is Figure 1G Specifically, the first distance and the second distance can be equal to the y-intercepts of the two lines. The slopes of the two can be determined by the first angle and the second angle of the laser and the redirected laser. Using the equations of the two lines, the intersection point can be determined algebraically.

[0091] According to an embodiment of the present disclosure, step 260 may include the following steps (eg Figure 6 (shown in the).

[0092] At step 261, the corner of the modulator that first passes through the laser light emitted from the laser source is defined as the origin. The XY position of the particle can be determined relative to the origin.

[0093] The distance traveled by the modulator in the first direction between the time corresponding to the first change in intensity and the time corresponding to the second change in intensity is determined at step 265. For example, the distance may be determined by multiplying the difference between the time corresponding to the first change in intensity and the time corresponding to the second change in intensity by the speed of the modulator.

[0094] At step 266, the XY position of the particle is determined based on the distance traveled by the modulator in the first direction between the time corresponding to the first change in intensity and the time corresponding to the second change in intensity. For example, the calculated distance and the width of the modulator, the distance of the mirror from the second side of the modulator, the known values ​​of the first angle and the second angle can be used to calculate the XY position of the particle. These parameters are Figure 2A and 2E Visible in.

[0095] According to an embodiment of the present disclosure, method 200 may further include, at step 270, passing the modulator through an air knife to remove particles from a surface of the modulator. Step 270 may be performed after determining the XY position of the particle at step 260.

[0096] exist Figure 1A In the configuration shown in FIG. 1 , the air knife is positioned between the laser source and the laser sensor. Thus, when the modulator is moved in a first direction, the air knife is configured to be turned off to avoid removing particles before the XY position of the particles is determined. Thus, method 200 may further include moving the modulator in a second direction, the second direction being opposite to the first direction. This is Figure 1G and 1H The air knife is configured to be turned on when the modulator is moved in the second direction so as to remove the particle from the modulator surface after the XY position of the particle is determined.

[0097] exist Figure 2A In the configuration shown in Figure 1, the air knife is positioned downstream of the laser source and the laser sensor. Figure 3A As shown in FIG. 2 , the air knife may be configured to turn on when the modulator is moved in a first direction to remove particles from the surface of the modulator. After determining the XY position of the particle and removing the particle from the surface of the modulator, method 200 may further include moving the modulator in a second direction. Figure 3B . By moving the modulator in a second direction, the modulator can be passed through the laser again. This can be used to confirm that the air knife has removed particles from the modulator surface, or to diagnose system-level problems.

[0098] With the disclosed method 200, the output signal of the laser reflected from the mirror can be used to determine the XY position of the particle on the modulator surface. By locating the particle, the cleaning process can be closed-loop, where feedback is provided to the system to confirm effective cleaning of the modulator and / or diagnose system-level problems.

[0099] Although the present disclosure has been described with respect to one or more specific embodiments, it should be understood that other embodiments of the present disclosure may be implemented without departing from the scope of the present disclosure. Therefore, the present disclosure is deemed to be limited only by the appended claims and reasonable interpretations thereof.

Claims

1. A detection system, comprising: a modulator configured to detect defects in the circuit, the modulator being movable in a first direction; a laser source positioned adjacent to a first side of the modulator, the laser source configured to emit laser light toward a second side of the modulator in a direction parallel to a surface of the modulator and at a first angle relative to the first direction, and the laser light partially overlaps the surface of the modulator; at least one mirror positioned adjacent the second side of the modulator opposite the first side and configured to redirect the laser light toward the first side of the modulator at a second angle relative to the first direction; a laser sensor positioned adjacent the first side of the modulator, the laser sensor configured to: detecting a first change in the intensity of the laser light received from the laser source when a particle on the surface of the modulator passes through the laser light emitted by the laser source; and detecting a second change in intensity of the laser light received from the laser source and redirected by the at least one reflector when the particle on the surface of the modulator passes through the laser light redirected by the at least one reflector; and A processor is configured to determine an XY position of the particle based on the first change in intensity and the second change in intensity.

2. The detection system of claim 1, further comprising an air knife configured to remove the particle from the surface of the modulator after determining the XY position of the particle.

3. The detection system of claim 2, wherein the air knife is positioned between the laser source and the laser sensor.

4. The detection system of claim 2, wherein the air knife is positioned downstream of the laser source and the laser sensor. The detection system of claim 1 , wherein the first angle and the second angle are between 0 degrees and 90 degrees.

6. The detection system of claim 1, wherein the at least one reflector comprises a pair of reflectors positioned at symmetrical angles relative to the first direction.

7. The detection system of claim 1, wherein the at least one reflector comprises a reflector positioned parallel to the first direction.

8. The detection system of claim 1, wherein the XY position of the particle is determined relative to an origin defined by a corner of the modulator that first passes through the laser light emitted from the laser source.

9. A detection system according to claim 8, wherein the XY position of the particle is determined based on a first distance between the laser source and the origin determined at a time corresponding to the first change in intensity and a second distance between the laser sensor and the origin determined at a time corresponding to the second change in intensity.

10. The detection system of claim 8, wherein the XY position of the particle is determined based on a difference between a time corresponding to the first change in intensity and a time corresponding to the second change in intensity.

11. The detection system of claim 1, wherein the XY position of the particle is determined based on the first angle and / or the second angle.

12. The detection system of claim 1, wherein the modulator is movable at a constant speed.

13. A detection method, comprising: moving a modulator in a first direction, the modulator configured to detect a defect in a circuit; emitting laser light by a laser source positioned adjacent to a first side of the modulator in a direction parallel to a surface of the modulator and at a first angle relative to the first direction toward a second side of the modulator, with the laser light partially overlapping the surface of the modulator; redirecting the laser light toward the first side of the modulator at a second angle relative to the first direction via at least one mirror positioned adjacent to the second side of the modulator opposite the first side; detecting, by a laser sensor positioned adjacent to the first side of the modulator, a first change in intensity of the laser light received from the laser source when a particle on the surface of the modulator passes through the laser light emitted by the laser source; detecting, by the laser sensor, a second change in the intensity of the laser light redirected by the at least one reflector and received from the laser source when the particle on the surface of the modulator passes through the laser light redirected by the at least one reflector; and An XY position of the particle is determined by a processor based on the first change in intensity and the second change in intensity.

14. The detection method of claim 13, further comprising passing the modulator through an air knife to remove the particles from the surface of the modulator.

15. The detection method of claim 14, wherein the air knife is positioned between the laser source and the laser sensor, and the air knife is configured to be turned off when the modulator is moved in the first direction. 16 . The detection method of claim 15 , further comprising moving the modulator in a second direction, the second direction being opposite to the first direction, wherein the air knife is configured to turn on when the modulator is moved in the second direction.

17. The detection method of claim 14, wherein the air knife is positioned downstream of the laser source and the laser sensor, and the air knife is configured to turn on when the modulator is moved in the first direction.

18. The detection method of claim 13, further comprising defining a corner of the modulator that first passes through the laser light emitted from the laser source as an origin, wherein the XY position of the particle is determined relative to the origin.

19. The detection method of claim 18, wherein determining, by the processor, the XY position of the particle based on the first change in intensity and the second change in intensity comprises: determining a first distance between the laser source and the origin at a time corresponding to the first change in intensity; determining a second distance between the laser sensor and the origin at a time corresponding to the second change in intensity; and The XY position of the particle is determined based on the first distance and the second distance.

20. The detection method of claim 18, wherein determining, by the processor, the XY position of the particle based on the first change in intensity and the second change in intensity comprises: determining a distance traveled by the modulator in the first direction between a time corresponding to the first change in intensity and a time corresponding to the second change in intensity; and The XY position of the particle is determined based on the distance traveled by the modulator in the first direction between the time corresponding to the first change in intensity and the time corresponding to the second change in intensity.

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