Optical triangular measurement system

Abstract

The embodiment of the utility model discloses an optical triangle measurement system, which comprises an illumination system, an imaging system, a motion system and a control system, and is characterized in that the illumination system comprises a line light source, and the imaging system comprises a camera and a second telecentric lens connected with the camera; the illumination system and the imaging system are respectively connected with the motion system; the control system is in communication connection with the motion system and is used for controlling the motion system to move so as to drive the illumination system and the imaging system to move, so that the incident angle of the illumination system and the reflection angle of the imaging system respectively reach a predetermined target incident angle; and the target incident angle is reflected into the imaging system, and the imaging system acquires an image for measuring the to-be-measured object, so that the measurement of the to-be-measured objects with different sizes can be realized.

Description

Technical Field

[0001] The present disclosure relates to chip measurement technology, and in particular to an optical triangulation measurement system. Background Art

[0002] As the packaging technology of semiconductor chip products develops from two-dimensional to three-dimensional, a new chip-to-substrate electrical interconnection method using bump manufacturing technology has emerged. Bump manufacturing technology is to make metal bumps (bumps) on the surface of the chip to provide a "point" interface for electrical interconnection between the chip and the substrate. It has been widely used in advanced packaging such as flip-chip (FC), wafer-level packaging (WLP), chip-scale packaging (CSP), and three-dimensional packaging (3D).

[0003] As semiconductor process technology becomes smaller and smaller, the height of the bumps on the original wafer that makes up the chip is also getting smaller and smaller. Currently, there are bump sizes of 2um. At present, the measurement of bumps of different sizes can be achieved through an optical triangulation system. In related technologies, the optical triangulation system is mainly composed of a line light source, a telecentric lens and a camera. The telecentric lens and the camera are connected through an interface and are called an imaging system. The installation of the imaging system and the line light source is affected by the optical lighting method. Generally, a reflective triangulation system is used, that is, the line light source and the imaging system are symmetrically distributed.

[0004] In the process of realizing the present disclosure, the inventors of the present disclosure discovered through research that with the development of semiconductor technology, there are many types of wafers, and the bumps on different types of wafers have various conditions such as height and density. In the related technology, the angle between the line light source and the horizontal axis in the optical triangulation system is fixed, which is restricted by the bump spacing and imaging depth of field and cannot be applied to the measurement of bumps on different types of wafers. Utility Model Content

[0005] The embodiments of the present disclosure provide an optical triangulation measurement system to achieve measurement of bumps on different types of wafers.

[0006] An optical triangulation system provided by an embodiment of the present disclosure includes an illumination system, an imaging system, a motion system and a control system, wherein the illumination system includes a line light source, the imaging system includes a camera and a second telecentric lens connected to the camera;

[0007] The lighting system and the imaging system are respectively connected to the motion system;

[0008] The control system is communicatively connected with the motion system, and is used for controlling the motion system to drive the illumination system and the imaging system to move, so that the incident angle of the illumination system and the reflection angle of the imaging system respectively reach predetermined target incident angles. After the light emitted by the line light source is incident on the object to be measured at the target incident angle, it is reflected to the imaging system at the target incident angle, and the imaging system collects images for measuring the object to be measured.

[0009] Optionally, in any embodiment of the present disclosure, the lighting system further comprises a first telecentric lens connected to the line light source; the motion system comprises: a first arc guide rail, a first angle driving mechanism and a first optical axis driving mechanism; the lighting system is slidably connected to the first arc guide rail, and the first angle driving mechanism is transmission-connected to the lighting system, and is used to drive the lighting system to slide on the first arc guide rail to adjust the angle of the optical axis of the lighting system; the first optical axis driving mechanism is transmission-connected to the first telecentric lens, and is used to drive the first telecentric lens to move along the optical axis direction;

[0010] a second arc guide rail, a second angle driving mechanism, and a second optical axis driving mechanism; the imaging system is slidably connected to the second arc guide rail, and the second angle driving mechanism is transmission-connected to the imaging system, and is used to drive the imaging system to slide on the second arc guide rail to adjust the angle of the optical axis of the imaging system; the second optical axis driving mechanism is transmission-connected to the second telecentric lens, and is used to drive the second telecentric lens to move along the optical axis direction;

[0011] The control system is communicatively connected with the first angle driving mechanism, the first optical axis driving mechanism, the second angle driving mechanism and the second optical axis driving mechanism respectively.

[0012] Optionally, in any embodiment of the present disclosure, the motion system also includes a first lens fixing member for fixing the first telecentric lens and a second lens fixing member for fixing the second telecentric lens, the first telecentric lens is connected to the first lens fixing member via the first optical axis drive mechanism, and the second telecentric lens is connected to the second lens fixing member via the second optical axis drive mechanism; the first lens fixing member is connected to the first arc guide rail via the first angle drive mechanism, and the second lens fixing member is connected to the second arc guide rail via the second angle drive mechanism.

[0013] Optionally, in any embodiment of the present disclosure, the optical triangulation system also includes a symmetrical connecting member connected to the motion system, and the symmetrical connecting member includes: a main bracket, a first rotating rod and a second rotating rod, each of which has one end connected to the bottom cross plate of the main bracket and can rotate around one end connected to the bottom cross plate of the main bracket, the other end of the first rotating rod is fixedly connected to the first lens fixing member, and the other end of the second rotating rod is fixedly connected to the second lens fixing member.

[0014] Optionally, in any embodiment of the present disclosure, the main bracket is fixedly arranged relative to the first arc-shaped guide rail and the second arc-shaped guide rail.

[0015] Optionally, in any embodiment of the present disclosure, the optical triangulation system further includes a monitoring system;

[0016] The monitoring system comprises: a distance sensor disposed on the main pole of the main support, and a distance meter communicatively connected to the distance sensor, at least one of the distance sensor and the distance meter communicatively connected to the control system;

[0017] The distance sensor is used to measure a first distance between the light outlet of the distance sensor and the bottom cross plate of the main bracket, a second distance between the light outlet of the distance sensor when the first rotating rod is perpendicular to the bottom cross plate of the main bracket, a third distance between the light outlet of the distance sensor when the second rotating rod is perpendicular to the bottom cross plate of the main bracket, a fourth distance between the light outlet of the distance sensor when the first rotating rod is rotated to a certain angle around the connecting end with the bottom cross plate of the main bracket, and a fifth distance between the light outlet of the distance sensor when the second rotating rod is rotated to a certain angle around the connecting end with the bottom cross plate of the main bracket, and sends the measured distance data to the distance meter for display;

[0018] At least one of the distance sensor and the distance measuring meter is used to send the distance data to the control system.

[0019] Optionally, in any embodiment of the present disclosure, the control system is also communicatively connected to at least one of the line light source and the camera.

[0020] Optionally, in any embodiment of the present disclosure, the control system includes a controller and a display module.

[0021] Optionally, in any embodiment of the present disclosure, it also includes a sample stage for placing a sample, and the sample stage is communicatively connected to the control system, and the control system is used to control the sample stage to move in the reverse direction at a preset scanning step and in a preset scanning direction, so that the optical triangulation system scans the sample in the preset scanning direction and at the preset scanning step.

[0022] Optionally, in any embodiment of the present disclosure, the driving mechanism in the motion system includes a driving motor or a driving cylinder.

[0023] Based on the embodiments of the present disclosure, a solution for implementing an optical triangulation system with adjustable measuring angle is provided. The optical triangulation system includes an illumination system, an imaging system, a motion system and a control system. The illumination system includes a linear light source. The imaging system includes a camera and a second telecentric lens connected to the camera. The illumination system and the imaging system are respectively connected to the motion system. The control system is in communication connection with the motion system. The motion system is controlled to move so as to drive the illumination system and the imaging system to move so that the incident angle of the illumination system and the reflection angle of the imaging system reach predetermined target incident angles respectively. After the light emitted by the linear light source is incident on the object to be measured at the target incident angle, the light is reflected by the target incident angle. The incident angle is reflected to the imaging system, and the imaging system collects images for measuring the object to be measured. Based on the structure of the embodiment of the present disclosure, it is possible to adjust the measurement angle and measure the height of objects to be measured of different sizes. It can be applicable to the measurement of bumps on different types of wafers, thereby meeting the measurement requirements of bumps on various types of wafers. Compared with the traditional optical triangulation measurement system with fixed measurement angle in the related technology, it does not require disassembly and reassembly of optical components to change the measurement angle and to achieve measurement of bumps of different sizes and spacings, thereby avoiding the work and time required for disassembly and reassembly of optical components, improving measurement efficiency and broadening the measurement range.

[0024] The technical solution of the present disclosure is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0026] The present disclosure may be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0027] Figure 1 FIG. 4 is a schematic diagram of the structure of an optical triangulation system according to an embodiment of the present invention.

[0028] Figure 2 FIG. 4 is a schematic structural diagram of another embodiment of the optical triangulation system disclosed in the present invention.

[0029] Figure 3FIG. 4 is a schematic diagram of the structure of another embodiment of the optical triangulation system disclosed in the present invention.

[0030] Figure 4 A schematic diagram of a measurement angle calculation principle in an embodiment of the present disclosure.

[0031] Figure 5 FIG. 4 is a schematic diagram showing the principle of performing bump measurement using the optical triangulation measurement system according to an embodiment of the present disclosure.

[0032] Figure 6 FIG. 4 is an image of a bump in an embodiment of the present disclosure.

[0033] Figure 7 This is an example of a tiled image in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure unless otherwise specifically stated.

[0035] Those skilled in the art can understand that the terms "first" and "second" in the embodiments of the present disclosure are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0036] It should also be understood that in the embodiments of the present disclosure, “plurality” may refer to two or more than two, and “at least one” may refer to one, two, or more than two.

[0037] It should also be understood that any component, data or structure mentioned in the embodiments of the present disclosure can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0038] In addition, the term "and / or" in the present disclosure is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present disclosure generally indicates that the associated objects before and after are in an "or" relationship.

[0039] It should also be understood that the description of the various embodiments in the present disclosure focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced to each other, and for the sake of brevity, they will not be described one by one.

[0040] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0041] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0042] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0043] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0044] In the related art, the angle between the line light source and the horizontal axis in the optical triangulation system is fixed, which is restricted by the bump spacing and imaging depth of field, and cannot be applied to the measurement of bumps on different types of wafers. For example, when the line light source is incident at a low angle, the bump spacing is small in the case of overly dense bump distribution, which will cause the line light source to be unable to reach the base of the wafer. There is even a problem that the image of the reflected light at the top of the bump exceeds the clear area of ​​the camera's depth of field at the camera end, and the bump height cannot be calculated. If you want to change the measurement angle, you need to manually replace the optical components of the optical triangulation system, disassemble and reassemble the optical components of the optical triangulation system, and the disassembly and assembly work involved is complicated, which greatly limits the measurement efficiency.

[0045] Figure 1 FIG. 1 is a schematic diagram of the structure of an embodiment of the optical triangulation measurement system disclosed in the present invention. Figure 1 As shown, the optical triangulation system of this embodiment includes an illumination system 11 , an imaging system 12 , a motion system 13 and a control system 14 .

[0046] Among them, the lighting system 11 includes a line light source 111, and in addition, it can also selectively include a first telecentric lens 112 connected to the line light source 111. The line light source 111 and the first telecentric lens 112 can be fixedly connected by a fixed adapter frame, or can be fixedly connected by other methods. The embodiment of the present disclosure does not limit the connection method between the two. Optionally, in the embodiment of the present disclosure, if the line width and line length of the line light source 111 are within the field of view and meet the preset observation requirements, the lighting system 11 can also only be provided with a line light source 111 without configuring the first telecentric lens 112.

[0047] The imaging system 12 includes a camera 121 and a second telecentric lens 122 connected to the camera 121. The camera 121 and the second telecentric lens 122 can be fixedly connected using a fixed adapter or other methods. The embodiment of the present disclosure does not limit the connection method between the two.

[0048] The lighting system 11 and the imaging system 12 are respectively connected to the motion system 13. In a specific implementation, the lighting system 11 and the imaging system 12 can be respectively relatively fixedly connected to the motion system 13, or the lighting system 11 and the imaging system 12 can be respectively arranged on the motion system 13. The embodiment of the present disclosure does not limit the connection between the lighting system 11 and the imaging system 12 and the motion system 13, as long as the motion system 13 can drive the lighting system 11 and the imaging system 12 when it moves.

[0049] The control system 14 is communicatively connected with the motion system 13, and is used to control the motion system 13 to move so as to drive the lighting system 11 and the imaging system 12 to move, so that the incident angle of the lighting system 11 and the reflection angle of the imaging system 12 respectively reach predetermined target incident angles. After the light emitted by the line light source is incident on the object to be measured (e.g., a wafer) at the target incident angle, it is reflected to the imaging system 12 at the target incident angle. The imaging system 12 collects images for measuring the object to be measured (e.g., a bump on a wafer), and can measure the size of the object to be measured (e.g., the height of a bump on a wafer) and / or the spacing between the objects to be measured (e.g., the distance between two adjacent bumps on a wafer).

[0050] Optionally, in some of the implementations, the control system 14 can be implemented by a controller provided on an electronic device such as a terminal device, a computer, or a server.

[0051] Based on this embodiment, a solution for implementing an optical triangulation system with adjustable measuring angle is provided. The optical triangulation system includes an illumination system, an imaging system, a motion system and a control system. The illumination system includes a linear light source, the imaging system includes a camera and a second telecentric lens connected to the camera, the illumination system and the imaging system are respectively connected to the motion system, the control system is in communication connection with the motion system, and the motion system is controlled to move to drive the illumination system and the imaging system to move, so that the incident angle of the illumination system and the reflection angle of the imaging system reach predetermined target incident angles, respectively. After the light emitted by the linear light source is incident on the object to be measured at the target incident angle, the light is reflected by the target incident angle. The incident angle is reflected to the imaging system, and the imaging system collects images for measuring the object to be measured. Based on the structure of the embodiment of the present disclosure, it is possible to adjust the measurement angle and measure the height of objects to be measured of different sizes. It can be applicable to the measurement of bumps on different types of wafers, thereby meeting the measurement requirements of bumps on various types of wafers. Compared with the traditional optical triangulation measurement system with fixed measurement angle in the related technology, it does not require disassembly and reassembly of optical components to change the measurement angle and to achieve measurement of bumps of different sizes and spacings, thereby avoiding the work and time required for disassembly and reassembly of optical components, improving measurement efficiency and broadening the measurement range.

[0052] Figure 2 FIG. 1 is a schematic diagram of the structure of another embodiment of the optical triangulation measurement system disclosed in the present invention. Figure 2As shown, in some of the implementations, the motion system 13 may include: a first arc guide 131, a first angle drive mechanism 132 and a first optical axis drive mechanism 133, and a second arc guide 134, a second angle drive mechanism 135 and a second optical axis drive mechanism 136. The control system 14 is respectively connected to the first angle drive mechanism 132, the first optical axis drive mechanism 133, the second angle drive mechanism 135 and the second optical axis drive mechanism 136 for communication. Among them, the lighting system 11 is slidably connected to the first arc guide 131, and the first angle drive mechanism 132 is connected to the lighting system 11 in a transmission manner, and is used to drive the lighting system 11 to slide on the first arc guide 131 to adjust the angle of the optical axis of the lighting system 11. The first optical axis drive mechanism 133 is connected to the first telecentric lens 112 in a transmission manner, and is used to drive the first telecentric lens 112 to move along the optical axis direction. The imaging system 12 is slidably connected to the second arc-shaped guide rail 134, and the second angle driving mechanism 135 is transmission-connected to the imaging system 12, and is used to drive the imaging system 12 to slide on the second arc-shaped guide rail 134 to adjust the angle of the optical axis of the imaging system 12. The second optical axis driving mechanism 136 is transmission-connected to the second telecentric lens 122, and is used to drive the second telecentric lens 122 to move along the optical axis direction.

[0053] In this embodiment, the control system 14 is specifically used to: drive the lighting system 11 to move by controlling the first angle driving mechanism 132 to slide along the first arc-shaped guide rail 131; and drive the imaging system 12 to move by controlling the second angle driving mechanism 135 to slide along the second arc-shaped guide rail 134.

[0054] Optionally, in some of the implementations, the driving mechanism in the motion system 13, such as any one of the first angle driving mechanism 132, the first optical axis driving mechanism 133, the second angle driving mechanism 135, and the second optical axis driving mechanism 136, can be implemented by any driving element with the function of driving hardware movement, such as a driving motor and a driving cylinder. The embodiments of the present disclosure do not limit the specific implementation method of the driving mechanism.

[0055] Optionally, see Figure 2 In other implementations, the motion system 13 may further include: a first lens fixing member 137 for fixing the first telecentric lens 114, and a second lens fixing member 138 for fixing the second telecentric lens 124, the first telecentric lens 114 is connected to the first lens fixing member 137 via a first optical axis driving mechanism 133, and the second telecentric lens 124 is connected to the second lens fixing member 138 via a second optical axis driving mechanism 136. The first lens fixing member 137 is connected to the first arc guide rail 131 via a first angle driving mechanism 132, and the second lens fixing member 138 is connected to the second arc guide rail 134 via a second angle driving mechanism 135.

[0056] In a specific implementation, the first lens fixing member 137 can be fixedly connected to the first angle driving mechanism 132 and the two can be integrally arranged on the first arc-shaped guide rail 131. The first lens fixing member 137 can be provided with a slide groove that matches the first arc-shaped guide rail 131, so that the first lens fixing member 137 can slide along the first arc-shaped guide rail 131 driven by the first angle driving mechanism 132. The first telecentric lens 112 can be fixed to the first optical axis driving mechanism 133, so that the first lens fixing member 137 can move along the optical axis direction driven by the first optical axis driving mechanism 133.

[0057] In a specific implementation, the second lens fixing member 138 can be fixedly connected to the second angle driving mechanism 135 and the two can be integrally arranged on the second arc-shaped guide rail 134. The second lens fixing member 138 can be provided with a slide groove that matches the second arc-shaped guide rail 134, so that the second lens fixing member 138 can slide along the second arc-shaped guide rail 134 driven by the second angle driving mechanism 135. The second telecentric lens 122 can be fixed to the second optical axis driving mechanism 136, so that the second lens fixing member 138 can move along the optical axis direction driven by the second optical axis driving mechanism 136.

[0058] Based on this embodiment, the motion system can be used to control the movement of the illumination system and the imaging system, thereby adjusting the incident angle of the illumination system and the reflection angle of the imaging system, and controlling the illumination system and the imaging system to move along the optical axis to achieve focus calibration of the imaging system along the optical axis, so as to compensate for the distance deviation of the focus position caused by the change in the measurement angle within a small range of distances.

[0059] See also Figure 2 In some other implementations, the optical triangulation system also includes a symmetrical connecting member 15 connected to the motion system 13, and the symmetrical connecting member 15 includes: a main bracket 151, a first rotating rod 152 and a second rotating rod 153, one end of which is connected to the bottom cross plate 1511 of the main bracket 151 and can rotate around one end connected to the bottom cross plate 1511 of the main bracket 151, the other end of the first rotating rod 152 is fixedly connected to the first lens fixing member 137, and the other end of the second rotating rod 153 is fixedly connected to the second lens fixing member 138.

[0060] Optionally, in some implementations, the main support 151 is fixedly arranged relative to the first arc-shaped guide rail 131 and the second arc-shaped guide rail 134 to prevent the lighting system 11 and the imaging system 12 from drifting in angle during measurement.

[0061] Figure 3 FIG. 1 is a schematic diagram of the structure of another embodiment of the optical triangulation measurement system disclosed in the present invention. Figure 3As shown, based on any of the above-mentioned optical triangulation system embodiments, the optical triangulation system of this embodiment may further include a monitoring system 16, which includes: a distance sensor 161 arranged on the main pole 1512 of the main bracket 151, and a distance meter 162 communicatively connected to the distance sensor 161, and at least one of the distance sensor 161 and the distance meter 162 is communicatively connected to the control system 14.

[0062] Among them, the distance sensor 161 is used to measure the first distance between the light outlet of the distance sensor 161 and the bottom cross plate 1511 of the main bracket 151, the second distance between the first rotating rod 152 and the light outlet of the distance sensor 161 when it is perpendicular to the bottom cross plate 1511 of the main bracket 151, the third distance between the second rotating rod 153 and the light outlet of the distance sensor 161 when it is perpendicular to the bottom cross plate 1511 of the main bracket 151, the fourth distance between the first rotating rod 152 and the light outlet of the distance sensor 161 when it is rotated to a certain angle around the connection end with the bottom cross plate 1511 of the main bracket 151, and the fifth distance between the second rotating rod 153 and the light outlet of the distance sensor 161 when it is rotated to a certain angle around the connection end with the bottom cross plate 1511 of the main bracket 151, and send the measured distance data (hereinafter referred to as: distance measurement data) to the distance measuring meter 162 for display. At least one of the distance sensor 161 and the distance meter 162 is used to send distance data to the control system 14, so that the control system 14 obtains the rotation angle of the first rotating rod 152 and the rotation angle of the second rotating rod 153 through the distance data, thereby determining the current incident angle reached by the lighting system 11 and the current reflection angle reached by the imaging system 12.

[0063] In this embodiment, the distance sensor can measure the distance by emitting laser and receiving its reflected light, and send the distance measurement data to the distance meter for display in real time, and transmit it to the control system for display and / or angle calculation, that is, calculate the incident angle of the lighting system and the reflection angle of the imaging system.

[0064] Figure 4 FIG. 1 is a schematic diagram of a measurement angle calculation principle in an embodiment of the present disclosure. Figure 4 As shown, in a specific implementation example, taking the calculation of the incident angle of the lighting system as an example, the angle calculation method is as follows:

[0065] First, the distance sensor 161 is used to measure the first distance D between the light outlet of the distance sensor 161 and the bottom cross plate 1511 of the main bracket 151, and the second distance x between the light outlet of the distance sensor 161 and the first rotating rod 152 when the first rotating rod 152 is perpendicular to the bottom cross plate 1511 of the main bracket 151. When the first rotating rod 152 rotates from the bottom cross plate 1511 perpendicular to the main bracket 151 to a certain angle α, the distance y from the light outlet of the distance sensor 161 to the first rotating rod 152 is measured. Then, the angle α of the first rotating rod 152 at this time can be calculated by the following formula (1):

[0066]

[0067] Likewise, the angle of the second rotating rod 153, ie, the reflection angle of the imaging system, can be measured in a similar manner.

[0068] If the distance from the light outlet of the distance sensor 161 to the first rotating rod 152 is the same as the distance to the second rotating rod 153, and the angle deviation between the first rotating rod 152 and the second rotating rod 153 calculated by the above formula (1) is zero (i.e., the angles are the same), it means that the lighting system and the imaging system are symmetrically distributed at this moment. If the control system 14 controls the movement of the first angle driving structure 132 and the second angle driving structure 135 to drive the illumination system and the imaging system to move to a certain target angle, and the distance from the light outlet to the first rotating rod 152 measured by the distance sensor 161 is different from the distance to the second rotating rod 153, and / or the angle of the first rotating rod 152 calculated based on the above formula (1) is different from the angle of the second rotating rod 153, it means that the sliding of the first angle driving structure 132 and / or the second angle driving structure 135 is not accurate. Based on whether the calculated angle deviates from the target angle set by the control system 14, the first angle driving structure 132 and / or the second angle driving structure 135 with inaccurate sliding can be determined, and the sliding accuracy of the first angle driving structure 132 and / or the second angle driving structure 135 with inaccurate sliding can be calibrated until both can reach the target angle required by the control system 14 according to the control of the control system 14, so as to ensure that the illumination system and the imaging system can be symmetrically distributed each time the angle is adjusted.

[0069] Based on this embodiment, the distance between the first rotating rod and the second rotating rod in the symmetrical connecting member is measured and displayed by the monitoring system to observe the symmetry of the first rotating rod and the second rotating rod, and the angle and angle deviation corresponding to the distance data can be displayed by the control system to observe whether the lighting system and the imaging system reach the position corresponding to the measured angle during the movement, as well as the symmetry of the lighting system and the motion system, thereby realizing real-time monitoring of the measured angle and its symmetry.

[0070] Alternatively, if Figure 2 and Figure 3 As shown, the optical triangulation measurement system of the present disclosure may also include a sample stage 18 for placing a sample (i.e., a wafer to be measured) 17, and the sample stage is in communication connection with the control system 14. The control system 14 may control the sample stage 18 to move in the reverse direction at a preset scanning step and in a preset scanning direction, so that the optical triangulation measurement system scans the sample 17 in the preset scanning direction and at a preset scanning step. In a specific implementation, an adsorption groove may be provided on the sample stage 18, and the sample 17 placed on the adsorption groove may be adsorbed to fix the sample 17. The embodiment of the present disclosure does not limit the specific structure and implementation of the sample stage 18.

[0071] In a specific test, during the movement of the lighting system 11 and the imaging system 12, the distance from the sample 17 to the first telecentric lens 112 (or the front end of the line light source 111) along the optical axis, and the distance to the second telecentric lens 122 (or the front end of the camera 121) along the optical axis need to be kept constant at all times. If a distance deviation occurs during the movement, it can be automatically adjusted by the first optical axis driving structure 133 and the second optical axis driving structure 136 accordingly.

[0072] In some of the implementations, the automatic adjustment method is: placing a bump-free wafer on the sample stage 18 as a sample, and observing the camera 121 collecting images of the sample on the display screen of the control system 14. Since the bump-free wafer has no bumps but only a substrate, its image in the image is a line; the control system 14 controls the first optical axis driving structure 133 to move up and down along the optical axis, driving the illumination system 11 to move up and down along the optical axis, and the control system 14 controls the second optical axis driving structure 136 to move up and down along the optical axis, driving the imaging system 12 to move up and down along the optical axis. In this process, the substrate imaging in the image is observed in real time, and the position where the number of pixels occupied by the substrate imaging line width is the smallest and the grayscale value of the imaging line width reaches above the preset grayscale value is found, which is the focused and clear position. In practical applications, the preset grayscale value may be 220, for example. When the grayscale value of the substrate imaging line width reaches above 220, the brightness is relatively high and can meet the test requirements. At this time, the substrate imaging reaches a thin and bright state, indicating that the current position of the lighting system 11 and the imaging system 12 is a position with higher focus clarity and the position can be fixed.

[0073] Based on this embodiment, during the movement of the lighting system 11 and the imaging system 12 to change the measurement angle, and during the movement up and down along the optical axis, the imaging effect can be observed in real time, which helps to find the appropriate measurement angle and focus clear position more quickly, and improve the measurement efficiency and the accuracy of the measurement results; in addition, the lighting system and the imaging system can be controlled to move along the optical axis, and the focus calibration of the imaging system along the optical axis can be achieved by observing the number of pixels and grayscale values ​​occupied by the substrate imaging line width during the movement, which can compensate for the distance deviation of the focus position caused by the change in the measurement angle within a small range of distances.

[0074] Optionally, in some of the implementations, the control system 14 is also communicated with at least one of the line light source 112 and the camera 122 so as to adjust the working parameters of the line light source 112 (such as the switch, brightness, etc. of the line light source 112), the working parameters of the camera 122 (such as the focal length, frame rate, etc. of the camera 122), and receive and display images captured by the camera 122.

[0075] Optionally, in a specific implementation, the control system 14 can be implemented by a controller and a display module (such as a display screen, a display, etc.) installed on an electronic device such as a terminal device, a computer, a server, etc., and other units except the control system 14 in the optical triangulation measurement system of the embodiment of the present disclosure can be specifically connected or communicated with the controller. Among them, the controller has a user interaction interface, and can receive the operating parameters of the lighting system and the imaging system set by the user (such as the operating parameters of the line light source, the operating parameters of the camera, etc.), the control parameters of the motion system (such as the motion parameters of the first angle drive mechanism, the first optical axis drive mechanism, the second angle drive mechanism, the second optical axis drive mechanism, etc.), the operating parameters of the monitoring system (such as the measurement parameters of the distance sensor and the display parameters of the distance meter, etc.), the motion parameters of the sample stage (such as the scanning step, the scanning direction, etc.), the processing parameters of the image collected by the imaging system (such as the parameters of the image synthesis direction, etc.) and the display parameters (such as whether to display in real time, etc.), etc. The display module can display the data sent by the controller.

[0076] The optical triangulation measurement system of the embodiment of the present disclosure is further described below by measuring bumps in a wafer using the optical triangulation measurement system of the embodiment of the present disclosure.

[0077] like Figure 5 FIG. 1 is a schematic diagram showing the principle of performing bump measurement using the optical triangulation measurement system according to an embodiment of the present disclosure. Figure 5In the figure, 171 is the bump in the wafer, 172 is the substrate in the wafer, θ is the incident angle of the line light source, and the imaging size of the bump 171 (i.e., the size of the bump image, the height value of the bump image) l can be expressed by the pixel size k in the imaging system multiplied by the number of pixels n: l = n × k. Among them, b = a × sin β, β = 2 × θ, a is the length of the bump in the incident direction of the light emitted by the line light source, b is the distance between the reflected light at the two endpoints corresponding to the length, and β is the angle between the incident light and the reflected light. If the magnification of the second telecentric lens is m, the height value H of the bump can be determined as follows:

[0078]

[0079] like Figure 6 As shown, it is an imaging diagram of a bump when the incident angle and the reflection angle are 30°. Figure 6 In the figure, the number of pixels in the height direction of the bump image (ie, the number of pixels representing the bump height) between the top image of the bump (called: the first reflected image) and the base image (called: the second reflected image) is 59 pixels.

[0080] In the disclosed embodiment, when the bump measurement of the wafer is performed using the optical triangulation system, the control system 14 can be used to control the sample stage 18 on which the wafer is located to move in the opposite direction at a preset scanning step and in a preset scanning direction, so that the optical triangulation system scans the wafer in a preset scanning direction and at a preset scanning step, and the imaging system 12 is used to capture images during each scan to obtain multiple frames of images. Thereafter, the multiple frames of images can be synthesized according to the preset scanning direction to obtain a tiled image.

[0081] Afterwards, by obtaining the number of pixels between the first reflection images of the tops of two adjacent bumps in the wafer in the height direction of the bump images in the tiled image, the distance value between the two adjacent bumps is determined based on the preset scanning step and the number of pixels between the first reflection images of the tops of the two adjacent bumps in the tiled image in the distance direction. For example, in a specific implementation, the distance value P between the two adjacent bumps can be determined based on the preset scanning step and the number of pixels between the first reflection images of the tops of the two adjacent bumps in the tiled image in the distance direction by the following formula (3):

[0082] P=w×n step Formula (3)

[0083] Where w represents the scanning step, n step Indicates the number of pixels in the distance direction between the first reflection images of the tops of two adjacent bumps in the tiled image.

[0084] like Figure 7As shown, it is an example of a tiled image in an embodiment of the present disclosure. In this embodiment, the preset scanning step is 10um (i.e. 1step=10um), and the number of pixels in the distance direction between the tops of two adjacent bumps in the first reflection image in the tiled image is 25 (i.e. 25 pixels), thereby determining the distance value P (Pitch) between the two adjacent bumps to be 250um (i.e. Pitch=250um).

[0085] Based on this embodiment, when the optical triangulation system scans the wafer according to a preset scanning direction and with a preset scanning step, the multiple frames of images correspondingly acquired by the imaging system are synthesized according to the preset scanning direction to obtain a tiled image, and the distance value between the two adjacent bumps is accurately determined based on the preset scanning step and the number of pixels in the distance direction between the reflection images of the top ends of the two adjacent bumps in the tiled image.

[0086] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referenced to each other.

[0087] The block diagrams of the devices, apparatuses, equipment, and systems involved in this disclosure are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including," "comprising," "having," and the like are open words, referring to "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or," and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0088] The system of the present disclosure may be implemented in many ways. For example, the system of the present disclosure may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. It should also be noted that in the system of the present disclosure, each component or each step may be decomposed and / or recombined. These decompositions and / or recombinations shall be regarded as equivalent solutions of the present disclosure.

[0089] The description of the present disclosure is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present disclosure to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present disclosure, and to enable those of ordinary skill in the art to understand the present disclosure and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. An optical triangulation system, characterized in that: It includes an illumination system, an imaging system, a motion system and a control system, wherein the illumination system includes a line light source, and the imaging system includes a camera and a second telecentric lens connected to the camera; The lighting system and the imaging system are respectively connected to the motion system; The control system is communicatively connected with the motion system, and is used for controlling the motion system to drive the illumination system and the imaging system to move, so that the incident angle of the illumination system and the reflection angle of the imaging system respectively reach predetermined target incident angles. After the light emitted by the line light source is incident on the object to be measured at the target incident angle, it is reflected to the imaging system at the target incident angle, and the imaging system collects images for measuring the object to be measured.

2. The system according to claim 1, characterized in that The lighting system also includes a first telecentric lens connected to the line light source; The motion system comprises: a first arc guide rail, a first angle driving mechanism and a first optical axis driving mechanism; the lighting system is slidably connected to the first arc guide rail, the first angle driving mechanism is transmission-connected to the lighting system, and is used to drive the lighting system to slide on the first arc guide rail to adjust the angle of the optical axis of the lighting system; the first optical axis driving mechanism is transmission-connected to the first telecentric lens, and is used to drive the first telecentric lens to move along the optical axis direction; a second arc guide rail, a second angle driving mechanism, and a second optical axis driving mechanism; the imaging system is slidably connected to the second arc guide rail, and the second angle driving mechanism is transmission-connected to the imaging system, and is used to drive the imaging system to slide on the second arc guide rail to adjust the angle of the optical axis of the imaging system; the second optical axis driving mechanism is transmission-connected to the second telecentric lens, and is used to drive the second telecentric lens to move along the optical axis direction; The control system is communicatively connected with the first angle driving mechanism, the first optical axis driving mechanism, the second angle driving mechanism and the second optical axis driving mechanism respectively.

3. The system according to claim 2, characterized in that The motion system also includes a first lens fixing member for fixing the first telecentric lens and a second lens fixing member for fixing the second telecentric lens, the first telecentric lens is connected to the first lens fixing member through the first optical axis driving mechanism, and the second telecentric lens is connected to the second lens fixing member through the second optical axis driving mechanism; the first lens fixing member is connected to the first arc guide rail through the first angle driving mechanism, and the second lens fixing member is connected to the second arc guide rail through the second angle driving mechanism.

4. The system according to claim 3, characterized in that The optical triangulation system also includes a symmetrical connecting member connected to the motion system, and the symmetrical connecting member includes: a main bracket, a first rotating rod and a second rotating rod, one end of which is respectively connected to the bottom cross plate of the main bracket and can rotate around one end connected to the bottom cross plate of the main bracket, the other end of the first rotating rod is fixedly connected to the first lens fixing member, and the other end of the second rotating rod is fixedly connected to the second lens fixing member.

5. The system according to claim 4, characterized in that The main bracket is fixedly arranged relative to the first arc-shaped guide rail and the second arc-shaped guide rail.

6. The system according to claim 4, characterized in that The optical triangulation system also includes a monitoring system; The monitoring system comprises: a distance sensor disposed on the main pole of the main support, and a distance meter communicatively connected to the distance sensor, at least one of the distance sensor and the distance meter communicatively connected to the control system; The distance sensor is used to measure a first distance between the light outlet of the distance sensor and the bottom cross plate of the main bracket, a second distance between the light outlet of the distance sensor when the first rotating rod is perpendicular to the bottom cross plate of the main bracket, a third distance between the light outlet of the distance sensor when the second rotating rod is perpendicular to the bottom cross plate of the main bracket, a fourth distance between the light outlet of the distance sensor when the first rotating rod is rotated to a certain angle around the connecting end with the bottom cross plate of the main bracket, and a fifth distance between the light outlet of the distance sensor when the second rotating rod is rotated to a certain angle around the connecting end with the bottom cross plate of the main bracket, and sends the measured distance data to the distance meter for display; At least one of the distance sensor and the distance measuring meter is used to send the distance data to the control system.

7. The system according to any one of claims 1 to 6, characterized in that: The control system is also in communication with at least one of the line light source and the camera.

8. The system according to any one of claims 1 to 6, characterized in that: The control system includes a controller and a display module.

9. The system according to any one of claims 1 to 6, characterized in that: It also includes a sample stage for placing samples, and the sample stage is communicatively connected to the control system. The control system is used to control the sample stage to move in the reverse direction at a preset scanning step size and in a preset scanning direction, so that the optical triangulation system scans the sample in the preset scanning direction and at the preset scanning step size.

10. The system according to any one of claims 2 to 6, characterized in that: The driving mechanism in the motion system includes a driving motor or a driving cylinder.

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