KR20110060041A - Apparatus and method for measuring 3d surface shape and system thereof - Google Patents

Abstract

PURPOSE: Apparatus, method, and system for measuring a 3D surface shape are provided to enable vertical focusing on a target and same-interval linear scanning using a telecentric F-Theta lens as the lens of a device for measuring the 3D surface shape. CONSTITUTION: An apparatus for measuring a 3D surface shape comprises a light source(141), a rotating mirror(145), a telecentric F-Theta lens(147), a light sensor(149) and a half reflector(143). The light source radiates laser light to the surface of a target, of which 3D surface shape is measured. The rotating mirror rotates at a given speed and deflects laser lights, which are radiated from the light source and reflected from the target. The telecentric F-Theta lens makes the laser light deflected from the rotating mirror enter the surface of the target perpendicular. The telecentric F-Theta lens linearly moves the laser light along the surface of the target and scans the surface of the target.

Description

Apparatus and method for measuring 3D surface shape and system

The present invention relates to a three-dimensional surface shape measuring apparatus and method and system for measuring the surface shape of an object in three dimensions, in particular by measuring the reflection angle of the reflected light in the object to be inspected by laser scanning The present invention relates to a three-dimensional surface shape measuring apparatus and method capable of measuring a three-dimensional shape, and a system thereof.

In today's industry, miniaturization of parts requires so-called ultra-small microfabrication systems with the minimum processing capacity required for their processing. Micro-fabrication systems require micromachining technology, micro / accuracy transfer technology, micro-assembly assembly, inter-process part measurement systems, and finally require systems to check the quality of the machined parts.

As the precision and surface finish of mechanical parts are more important than ever in the modern industry, the measurement and understanding of surface shape is more urgently needed in the semiconductor industry, which is the core of the modern precision industry. .

In particular, three-dimensional surface shape measurement is essential for securing and improving the surface information of high value-added mechanical parts required by the industry, and occupies an important position for the determination and prediction of the normal function performance of precision parts. There is an increasing need for a three-dimensional surface shape measurement system for quickly and automatically performing quality inspection.

In this situation, the optical measurement method has attracted attention as a useful measurement method in the field of cracking, defect detection, and surface morphology.

The key to performance in a three-dimensional surface profiler is high speed and high resolution. To this end, the three-dimensional surface shape measuring instrument using the optical measuring principle should have a high resonance frequency and a small spring constant. For this purpose, an optical trapping microscope (OTM) using optically captured microparticles as a probe has been proposed. . This is because the light capture microscope has only a spring force and a very small mass of particles because the restoring force acting on the particles is only due to light.

On the other hand, as a system for inspecting the quality of a component, a small component surface measurement system using an atomic force microscope, which has been in the spotlight with recent nano-related technology development, has been proposed. An atomic force microscope is a device that can measure the surface of a sample to an atomic unit that cannot be observed with a conventional microscope.

The development of atomic force microscopy allows more accurate measurement of the sample surface shape, but the limit of the general measurement range in the absence of a separate driving device is generally 100 x 100 x 10 μm ³ or less. The measuring area is very limited.

Therefore, there is a problem in overall observation of the surface of a relatively large sample such as a small component using the light trapping microscope or atomic force microscope described above.

In other words, the performance is not only measured at high speed and high resolution in precision three-dimensional surface shape measuring device, but also depends on how fast and high resolution can be measured for the measurement range required by the user.

On the other hand, large equivalent wavelength interferometers have been studied to accurately and quickly measure machined surfaces in a large area. The equivalent wavelength interferometer uses a method of making and measuring a larger equivalent wavelength by inclining the light onto the surface of the object without using the wavelength of the light source as it is.

However, since the equivalent wavelength interferometer uses a prism or a diffraction grating to obtain a large equivalent wavelength by obliquely irradiating light onto the measurement surface, a large number of unnecessary diffraction light components are generated. There is a problem that the size of the measuring device is increased by using a beam splitter.

Since the measuring device using the equivalent wavelength interferometer requires a measuring device that is relatively large in size compared to the size of the sample to be measured, in order to be applied to various industrial sites, it is equipped with a space to accommodate it, and installed and driven. There is a problem that the auxiliary device for the need to be provided a lot.

Nevertheless, the equivalent wavelength interferometer has a very good resolution because it can measure the surface at once. However, there is a disadvantage that the measuring range is limited. In addition, there is a critical error factor of 2π ambiguity on the discontinuous surface of the specimen.

As these methods have their own advantages and disadvantages, new measurement methods are being developed to overcome their shortcomings. Among them, the confocal principle is used to measure the shape of cells or tissues. It is used in, and is now widely applied to semiconductor surface inspection.

The confocal principle is a principle of obtaining surface information by irradiating a beam from a light source to a sample surface through a focusing lens, detecting a change in intensity of the beam reflected from the sample surface, and converting the beam into an electrical signal. Confocal microscopy (CFM) using this principle can obtain a three-dimensional image of the roughness or height of the sample surface that cannot be observed with a general optical microscope, and the image processing speed is fast and convenient to use.

However, the conventional measuring method using the confocal principle performs a scan for each direction while moving the sample in the three-axis (XYZ) direction to measure the three-dimensional surface shape to obtain data on one point on the surface of the sample. Detects the Z position for that point. Then, the sample is moved to a neighboring point in the X direction to perform a scan in the Z direction again. This process is performed for one line and then moved to the next line in the Y direction to repeat the Z direction scan and the X direction scan. As described above, the measurement method using the conventional confocal principle has a problem that it takes a lot of measurement time because it needs to scan about three axes.

In addition, since a conventional measuring apparatus using a confocal principle requires a plurality of lens systems for scanning in each of the three axis directions, there is a limitation that the size of the measuring apparatus cannot be miniaturized like the equivalent wavelength interferometer.

It is therefore an object of the present invention to provide a three-dimensional surface shape measuring apparatus and method and a system capable of measuring three-dimensional surface shape at high speed.

In addition, another object of the present invention is to provide a three-dimensional surface shape measuring apparatus and method and system capable of miniaturization by minimizing the measurement distance between the measuring device and the inspected object.

In addition, another object of the present invention is to provide a three-dimensional surface shape measuring apparatus and method and system having a high resolution while measuring a relatively large area with respect to the measurement area provided by a conventional measuring device.

In addition, another object of the present invention to provide a three-dimensional surface shape measuring apparatus and method and system that can be applied in a variety of working environment by implementing the three-dimensional surface shape measuring apparatus as a single module.

The three-dimensional surface shape measuring apparatus according to the present invention for achieving the above object, the light source for irradiating the laser light to the surface of the object to be measured the shape of the three-dimensional surface; A rotating mirror which rotates at a constant speed and deflects the laser light irradiated from the light source and the laser light reflected from the inspected object; The laser beam deflected from the rotating mirror is incident on the surface of the inspected object vertically, and the laser beam moving according to the rotation angle of the rotating mirror is moved along the surface of the inspected object in a straight line to scan the surface of the inspected object. A telecentric F-Theta lens for converging laser light reflected from the scanned object; An optical position sensor for receiving a laser beam reflected from the inspected object and deflected from the rotating mirror to measure a deflection degree of the received laser beam; And a semi-reflective mirror which reflects the laser light of the light source to the rotation mirror, and is reflected from the inspected object to transmit the laser beam deflected from the rotation mirror to be incident to the optical position sensor.

In addition, the three-dimensional surface shape measurement apparatus according to the present invention, the loading unit for loading the test object to the measurement position; A stage for aligning the inspected object mounted to the loading unit; A camera for photographing the entire state of the inspected object mounted on the loading unit; And a distance measuring device for measuring the height and the horizontality of the inspected object, by measuring the three-dimensional surface shape with one miniaturized device.

In addition, the three-dimensional surface shape measurement apparatus according to the present invention, a synchronization sensor for controlling the synchronization of the optical position measurement time of the optical position measurement sensor by capturing the time point to measure the laser light incident the optical position measurement sensor; By including it, it is possible to collect only valid data, thereby improving measurement speed and increasing data storage efficiency.

In addition, the three-dimensional surface shape measurement method according to the invention, the step of loading the inspection object to the loading unit; Photographing the entire state of the loaded test object; Aligning the loading unit with a test position of the test object; Measuring a three-dimensional surface of the aligned test object; Collecting and storing three-dimensional surface data of the measured object; Analyzing the stored data; And displaying a three-dimensional surface shape of the inspected object according to the analyzed data.

In addition, the three-dimensional surface shape measurement method according to the invention, before measuring the three-dimensional surface of the aligned inspection object, measuring the horizontal degree of the inspection object; Adjusting the horizontal level of the inspected object according to the measured horizontality; Performing initial scanning on the horizontally adjusted inspected object; And precisely adjusting the position of the inspected object according to the initial scanning result. Further, the initialization process may be performed, thereby enabling more accurate measurement.

In addition, the three-dimensional surface shape measurement system according to the present invention, the light source for irradiating the laser light to the surface of the object to be measured the shape of the three-dimensional surface, the laser light irradiated from the light source and rotated at a constant speed and the test object The rotating mirror for deflecting the laser beam reflected from the object and the laser beam spot which is deflected from the rotating mirror perpendicularly to the surface of the inspected object, and moves according to the rotation angle of the rotating mirror, the surface of the inspected object. A telecentric F-Theta lens which scans the surface of the inspection object by moving in a straight line and converges laser light reflected from the scanned inspection object, and a laser beam reflected from the inspection object and deflected from the rotation mirror; And a light position sensor for measuring a deflection degree of the received laser light, and a laser of the light source. And the reflection time in the foreground, is reflected by the inspected object optical part including a half mirror, which was transmitted through the deflected laser beam from the rotating view to be incident to the optical position sensor; A loading unit for loading the inspected object to a measurement position, a stage for aligning the inspected object mounted on the loading unit, a camera for photographing the entire state of the inspected object mounted on the loading unit, and the inspected object An adjusting unit including a range finder for measuring a horizontal level of the; And a motion board for controlling driving of the loading unit and the stage, a DAQ storing data measured at high speed from the optical unit, a storage unit storing data applied from the DAQ, the optical unit, an adjusting unit, And a central processing unit including a control operation unit for controlling the operation of the motion board, the DAQ, and the storage unit.

At this time, the three-dimensional surface shape measurement system according to the present invention, the synchronization sensor for capturing the point of time to measure the laser light incident by the optical position measurement sensor to control the synchronization of the optical position measurement time of the optical position measurement sensor; By including it, it is possible to collect only valid data, thereby improving measurement speed and increasing data storage efficiency.

In addition, the stage of the three-dimensional surface shape measurement system according to the present invention, the XYZ stage to align the inspection position of the inspection object by moving the loading portion back and forth, left and right, up and down, and by adjusting the inclination of the loading portion And a six-axis stage including a tilt stage for horizontally adjusting the inclination of the inspection position of the object and a rotation stage for aligning the inspection position of the inspected object by rotating the loading unit.

As described above, according to the present invention, the telecentric F-Theta lens is used as the lens of the three-dimensional surface shape measuring apparatus, and thus the linear scans at equal intervals can be performed while vertically focusing on the inspected object.

In addition, the present invention can minimize the measurement distance between the measuring device and the inspected object by using the telecentric F-Theta lens as the scanning lens of the three-dimensional surface shape measuring device, thereby miniaturizing the size of the measuring device. There is an advantage to that.

In addition, the present invention has an advantage of improving the constant speed of scanning by using a high-speed rotating mirror.

In addition, the present invention has the advantage that can significantly improve the surface measurement speed of the inspection object by using a high-speed rotary mirror and DAQ.

In addition, the present invention provides a device and method for measuring a relatively wide area with respect to a measurement area provided by a conventional measuring device and having a high resolution, and a system thereof, thereby satisfying the needs of the user for the function. It can work.

In addition, the present invention has the advantage that can be applied in a variety of working environment by implementing the three-dimensional surface shape measuring apparatus as a single module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be given with reference to the accompanying drawings. It should be noted that the same components in the drawings represent the same numerals wherever possible. Specific details are set forth in the following description, which is provided to provide a more thorough understanding of the present invention. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

First, FIG. 1 is a main configuration diagram of an optical unit of a three-dimensional surface shape measuring apparatus according to the present invention. Referring to FIG. 1, the optical measuring principle of the three-dimensional surface shape measuring apparatus according to the present invention will be described in detail.

As shown, the optical portion of the three-dimensional surface shape measuring apparatus according to the present invention, the light source 141, the semi-reflective mirror 143, the rotating mirror 145, the telecentric F-Theta lens 147 and the light It consists of a position measuring sensor 149. In addition, the light diffuser 142 for adjusting the light source from the light source 141 to the light beam of the required shape may be further provided.

The light source 141 irradiates a laser beam to the surface of the inspection object to be measured in the shape of the three-dimensional surface. The light source 141 uses a laser light having a characteristic of parallel light and monochromatic light in order to minimize the size of the focal point formed on the inspected object. In particular, the light source 141 of the three-dimensional surface shape measuring apparatus according to the present invention measures the shape of the inspected object by using the telecentric F-Theta lens 147, thereby focusing the laser beam between the inspected object and the device. In order to minimize the required distance, the overall size of the equipment can be minimized.

The semi-reflective mirror 143 reflects the laser light of the light source 141 to the rotating mirror 145, and transmits the laser light reflected from the inspected object to be incident to the optical position sensor 149.

The rotating mirror 145 rotates at a constant speed and deflects the laser light irradiated from the light source 141 and the laser light reflected from the inspected object. In particular, the rotating mirror 145 according to the present invention can be performed at a high speed by rotating at a constant speed and a high speed. Therefore, it is preferable that the rotating mirror 145 uses a rotating cross-section mirror having good uniformity, convenience of operation, and high concentration of the scanning light beam. In addition, it is preferable to use a servo motor for constant speed and high speed rotation of the rotating mirror 145, and a galvano scanner, polygon, or the like may be used.

The telecentric F-Theta lens 147 injects the laser light deflected from the rotating mirror 145 perpendicularly to the surface of the inspected object and moves the laser light moving according to the rotation angle of the rotating mirror 145. The surface of the inspected object is scanned by moving in a straight line along the surface of the inspected object, and the laser beam reflected from the scanned inspected object is converged. In particular, the telecentric F-Theta lens 147 according to the present invention vertically enters the laser light into the inspected object, thereby converging the reflected light reflected from the inspected object in the same path.

In particular, since the use of an additional lens system is not necessary according to the measurement plane vertical incidence characteristic of the telecentric F-Theta lens 147, the distance between the object side lens and the inspected object can be minimized. In addition, since the offset of the data measured by scanning according to the constant velocity linear scanning characteristic of the telecentric F-Theta lens 147 does not need to be corrected, data can be stored and analyzed at high speed in response to high speed data scanning. .

The telecentric F-Theta lens 147 is generally used in a device such as a laser marker or a laser printer. Unlike the conventional application of the telecentric F-Theta lens 147 to irradiate a laser beam in one direction of the incident or the exit, the present invention is incident. It is used to measure the surface shape of the inspected object while both and emission are processed by the same optical system.

The optical position sensor 149 receives a laser beam reflected from the inspected object and measures a deflection degree of the received laser beam. The optical position sensor 149 is a quadrant detector or an array image sensor. This can be used. In the following description, a quadrature detector will be mainly used, and the quadrature detector generates a voltage signal corresponding to the amount of light detected in each of the four divided sectors, and the generated voltage signal is then centered on the light beam detected by the quadrature detector. The position is calculated and thus used to analyze the shape of the surface of the object.

Figure 2 is a perspective view of the top plate of the three-dimensional surface shape measuring apparatus according to the present invention, showing the optical portion of Figure 1 mounted on the top plate to perform each function in the device. In particular, referring to Figure 2, the rotating mirror 145 is mounted to be rotated by the servo motor 123 for the constant speed and high speed rotation.

On the other hand, reference numeral 111 is a camera module is used to photograph the overall appearance of the inspection object to measure the three-dimensional surface shape. The user selects a portion to be measured from the entire image of the inspected object photographed by the camera module 111.

Reference numeral 113 is used as a distance measurer to adjust the height and level of the inspected object by measuring the distance between the optical unit and the inspected object, and it is preferable to use a laser range finder. When the distance between the optical unit and the inspected object is measured by the distance measurer 113, the height of the inspected object is adjusted to be a predetermined distance.

Reference numeral 112 denotes a reflector that is to be measured on the three-dimensional surface shape is loaded on the lower portion of the upper plate of Figure 2, so that the entire image of the inspected object can be taken from the position where the camera module 111 is mounted It is used to reflect the illumination of the camera module 111, including the image.

3D surface measurement system according to the present invention will be described with reference to Figures 6 and 7 for the horizontal adjustment according to the entire image shooting and the distance measurement of the inspected object using the camera module 111 and the distance measurer 113 And the method will be described again in detail.

Figure 3 is an internal perspective view of the three-dimensional surface shape measuring apparatus according to the present invention, the top plate of Figure 2 is mounted, the three-dimensional surface shape measurement combined with the necessary adjustment and auxiliary elements for measuring the three-dimensional surface shape of the inspection object The overall appearance of the device is shown. In addition, Figure 4 is an external perspective view of the three-dimensional surface shape measuring apparatus according to the present invention, showing a state in which the three-dimensional surface shape measuring apparatus of Figure 3 is covered for use in an actual industrial site, reference numeral 20 is a test object In order to measure the loading of the loading unit 121 when the cover 20 is instructed to open.

First, referring to FIG. 3, the upper plate 100 described above is fixed on a cradle of an apparatus, and below the loading unit 121, an X-axis stage 131a, a Y-axis stage 131b, and a Z-axis stage ( 131c, the left and right tilt stage 133a, the front and rear tilt stage 133b, and the adjustment part comprised from the rotation stage 135 are mounted. The camera module 111 and the distance measurer 113 described with reference to FIG. 2 are included in the adjustment unit in function.

The adjusting unit performs a function of aligning the correct object to an accurate measurement position by moving and rotating the inspected object so that the optical unit can measure the inspected object more accurately. To this end, the adjusting unit inserts and withdraws the test object into the measurement position, aligns the position of the test object to the correct position, and provides the user with the entire image of the test object so that the user can select the measurement position.

In addition, since the three-dimensional surface shape that the optical unit can scan in the primary alignment position is limited to one linear region, the adjusting unit serves to align the adjacent linear scan region by moving the inspected object. In addition, when the user selects a plurality of measurement positions from the entire image of the inspected object, when the scanning operation at one measuring position is completed, the adjusting unit moves to the next measuring position to move the position of the inspected object to the correct position. It also performs the sorting function.

The loading unit 121 is a portion in which an object to be measured to measure a three-dimensional surface shape is loaded. When loading the object, the cover 20 shown in FIG. 4 is opened, and the object is loaded through the open part. do. When the inspected object is loaded into the loading unit 121, the cover 20 is closed, and the inspected object moves along the X axis stage 131a to a designated measurement position under the optical unit 100.

Subsequently, the six-axis stage including the Y-axis stage 131b including the X-axis stage 131a, the Z-axis stage 131c, the left-right Tilt stage 133a, the front-rear Tilt stage 133b, and the rotation stage 135 By adjusting, the position of the object under test is aligned with the measurement position specified by the user. When the distance between the optical unit and the inspected object is measured by the distance measurer 113, the height of the inspected object is adjusted to be a predetermined distance by the Z-axis stage 131c.

Alignment of the measurement position of the inspection object by the six-axis stage will be described in detail later in the three-dimensional surface measurement system and method according to the present invention described with reference to FIGS. 6 and 7.

On the other hand, the optical unit and the adjustment unit is mounted on the vibration damping table 30 so as not to be affected by vibration or shock from the outside for precise measurement. The vibration damping table 30 may be manufactured by a stone tablet, etc., and is a table on which a three-dimensional surface shape measuring device according to the present invention is mounted. It consists of a plate of material.

The isolator 40 allows the vibration damping table 30 to which the 3D surface shape measuring device is directly mounted to be mounted on the lower frame 50 at the same time, and can be mounted without being affected by vibration or shaking from the surrounding environment. To absorb vibrations or vibrations.

5 is a perspective view of a three-dimensional surface shape measurement system according to the present invention, the three-dimensional surface shape measurement data of the test object measured from the three-dimensional surface shape measurement apparatus as shown in the end to the central processing unit of the PC or server form The data is stored, analyzed, reconstructed by the central processing unit, and displayed on the display device 117 to provide the measurement result to the user. An example of a three-dimensional surface shape measurement result according to the present invention provided through the display device 117 is illustrated in FIG. 12.

On the other hand, reference numeral 115 denotes a user input device, the user can request the required measurement results through the input device 115, or can set various requests in the measurement step to obtain the corresponding measurement results.

6 and 7, the method of measuring the three-dimensional surface shape according to the present invention by looking at the detailed internal components and the operations performed by the respective components of the three-dimensional surface shape measurement system according to the present invention as described above. Will be described in detail. Figure 6 is a block diagram of a three-dimensional surface shape measurement system according to the present invention, Figure 7 is a control flowchart showing a three-dimensional surface shape measurement method according to the present invention.

As shown, the three-dimensional surface shape measurement system according to the present invention, the loading device 121 for loading the inspection object, and the inspection object loaded in the loading device 121 to move to the position to be measured and to the correct position It comprises a six-axis stage 130 to align, and the motion board 120 for controlling the operation of the loading device 121 and the six-axis stage 130. The motion board 120 also controls the operation of the servo motor 123 for rotating the rotating mirror of the optical unit 100 at constant speed and high speed.

The motion board 120 is a part that performs a function of controlling the operation of all components that perform physical movement in the three-dimensional surface shape measurement system according to the present invention, each component in consideration of the overall efficiency of the system It is preferable that the control unit 110 is configured separately from the control unit 110 which converts and stores an electrical signal into data for the element and analyzes the data. The motion board 120 is controlled by the control operation unit 110.

The control operation unit 110 controls the motion board 120 to drive the loading device 121 and the 6-axis stage 130 so that the inspected object is aligned with the measurement position.

In addition, the control operation unit 110 controls the camera 111 and the laser range finder 113 to measure the entire image and the distance of the object to be inspected, and provides the captured image to the user through the display device 117. In addition, the measurement position selection of the user is input through the input device 115 and stored in the storage device 150. The control operation unit 110 controls the motion board 120 according to the distance measured from the distance measuring unit 113 to adjust the horizontal level of the inspected object.

In addition, the control operation unit 110 controls the light source 141 to allow the optical unit 140 to measure the three-dimensional surface shape of the object to be inspected, and to control the DAQ 130 generated from the optical position measuring sensor 149 The voltage signal to be stored in the storage device 150. In this case, the control operation unit 110 controls the synchronization sensor 119 to allow the optical position measurement sensor 149 to detect only the surface scanning data of the inspected object. Accordingly, the DAQ 130 can collect and store only valid data, thereby improving measurement speed and increasing data storage efficiency.

In addition, the control operation unit 110 stores the voltage signal applied from the optical position sensor 149 in the temporary buffer in the section in which the surface of the inspection object is scanned by the rotating mirror 145, and the rotating mirror ( By controlling the DAQ 130 to store the voltage signal stored in the temporary buffer in the storage device 150 in a section where the surface of the test object is not scanned, the temporal efficiency in data measurement and storage is further increased. Can be.

On the other hand, when the rotary cross-sectional mirror is used as the rotary mirror 145 used in the three-dimensional surface shape measurement apparatus according to the present invention, the ratio of the interval (time) to the interval (time) for scanning the light beam or galvanoscanner or Since it has a disadvantage that it is relatively longer than the rotary face mirror, the use of the synchronous sensor 119 together with the above-described constant speed and high speed servo motor 123 is very efficient.

As described above, in the three-dimensional surface shape measurement apparatus according to the present invention, since the high-speed rotating mirror 145 is used to minimize the measurement time, the optical position sensor 149 reacts in a short time. Therefore, the data measured according to the three-dimensional surface shape measurement method according to the present invention is stored in the storage device 150 through the DAQ 130, which is a high-speed data collection device. In particular, in the method of measuring a three-dimensional surface shape according to the present invention, the DAQ 130 stores the measured data in a file form every scan to increase the memory efficiency of the storage device 150. A large amount of data obtained through the DAQ 130 is separated and stored for analysis and representation in a form having a variety of information.

Meanwhile, after the measured data is first stored in the storage device 150, the control operation unit 110 may call and analyze the stored value, or may simultaneously analyze the stored data. In addition, the analyzed result value is stored in the storage device 150 and displays the corresponding result on the display device 117 according to a preset user request and additional request.

Next, the method of measuring the three-dimensional surface shape according to the present invention will be described in detail with reference to FIGS. 6 and 7. FIG. 7 sequentially illustrates a control process performed by the control operation unit 110 of FIG. 6 for measuring a 3D surface shape according to the present invention.

First, the test object is loaded through the loading apparatus 121 in step S01, and the entire image of the test object is taken by controlling the camera 111 in step S03. Subsequently, the entire image of the inspection object photographed in step S03 is displayed on the display device 117, and in step S05, it is determined whether there is a user input of the measurement area selection. The user selects the measurement area through the input device 115 in response to the measurement area selection request of the control operation unit 110 in step S08 through the display device 117.

When the selection of the measurement area in step S07 is completed, the control operation unit 110 controls the motion board 120 so that the 6-axis stage 130 aligns the inspected object to the test position, and proceeds to step S11 to determine whether to initialize. To judge. The determination of the initialization of the step S11 is to omit unnecessary initialization process when performing a process for improving the accuracy of the three-dimensional surface shape measurement.

In order to obtain precise data, the degree of focusing and the tilt of the laser light are very important when the laser light from the light source 141 is reflected after being incident on the inspected object and received by the light position measuring sensor 149. Therefore, a process of analyzing the data measured by the optical position sensor 149 and precisely controlling the tilt and height of the inspected object by using the distance measurer 113 is required.

For the same reason as above, the control operation unit 110 controls the distance measurer 113 in order to measure the horizontality of the object under test in step S13, and in accordance with the distance measured from the distance measurer 113 in step S15. Control relevant components to control Subsequently, the control operation unit 110 performs initial scanning by controlling the optical unit 140 in step S17, and performs final fine adjustment in step S19 according to the result.

On the other hand, the control operation unit 110 does not perform the initialization step of the above-described step S13 to S19 when moving only the scanning line in the same measurement position or when performing the measurement for the inspection area of the other location of the same inspection object This prevents the delay of the measurement time due to the unnecessary initialization step.

When the initialization step is completed, the control operation unit 110 measures the three-dimensional surface in step S21, collects and stores the three-dimensional data measured in step S23, and in step S25, when all the measurement areas are measured in steps S27 to S31. Analyzes the stored data, displays them by reconstructing them into 3D surface shape information. If the measurement area is not finished in step S25 or if another measurement area is registered in step S33, the control operation unit 110 moves to the scan position in step S26 to continuously perform the three-dimensional surface measurement step of step S21. To perform.

As described above, the measurement result of the test object is converted into voltage values of the optical position sensors 149 and PSD, collected through the DAQ 130, and stored in the storage device 150 (HDD). The stored data can be read back after the measurement is completed. Through this read value, the 3D height information of the inspected object is finally restored.

The surface of an object having a three-dimensional surface shape may be regarded as having a three-dimensional height function. If the three-dimensional height function is defined as z = f (x, y), the slope of the surface may be defined as a derivative of height. It can be defined as Equation 1.

In addition, thereby moving the position of a laser beam is twice as if it reflected at an angle, defining a travel path length of the reflected light by the line l, the multiple of the angle of reflection of the light to help l in accordance with the test water gradient function incident on the inspected object. Therefore, the position of the reflected light measured by the optical position measuring sensor may be calculated as in Equation 2 below.

In the case of a quadrant detector commonly used as an optical position sensor, there are four divided optical sensors, and the amount of light that reaches each divided region (hereinafter referred to as “sector”) is compared with each other. The position of the light beam is calculated. If the light quantity of the light beam reaching each region is defined as A, B, C, and D, and the radius of the light position measuring sensor is defined as R, it may be calculated as in Equation 3 below. .

The data collected and stored by the DAQ 130 is a voltage value proportional to A, B, C, and D. The control operation unit 110 reads the stored A, B, C, and D, which is a three-dimensional shape of the test object. By reconstructing z, the above equation may be obtained through an inverse operation process as shown in Equation 4 below.

Here Cy (x) is introduced as a function of the integral constant for the concatenation of the y-direction height function at a specific x coordinate and the y-direction height function at an adjacent x coordinate.

Hereinafter, a process of storing and analyzing three-dimensional surface shape measurement data according to the three-dimensional surface shape measurement method according to the present invention will be described in detail with reference to FIGS. 8 to 12.

8 is a view showing a data storage value storage process of the optical position sensor according to the three-dimensional surface shape measurement method of the present invention, Figure 9 is a light quantity position of the optical position sensor according to the three-dimensional surface shape measurement method of the present invention 10 is a view showing the calculation process, Figure 10 is a view showing the slope calculation process of the surface according to the three-dimensional surface shape measurement method of the present invention, Figure 11 is a process of calculating the height of the surface according to the three-dimensional surface shape measurement method of the present invention It is a diagram showing.

The position and the displacement of the reflected light reaching the optical position sensor 149 are different from each other in the displacement calculation method according to the optical position sensor 149. Therefore, in the detailed description of the present invention, a quadrant detector used as a conventional optical position measuring sensor 149 will be described as an example.

Analysis of the three-dimensional surface shape measurement data measured according to the three-dimensional surface shape measurement method according to the present invention may be performed by performing the following processes.

<1. Read Stored Data>

This process is a process of reading the data stored in the storage device 150 in order in the measuring step. As shown in FIG. 8, the data are each divided into four sectors A and B of the optical position sensor PSD. , C and D) are divided into data measured from four sensors, respectively, and can be divided into a plurality of lines and a plurality of points within the order of scanning the surface of the inspection object. have.

For example, if the surface of an object of 20 X 20 mm2 is divided into 5,000 lines and 5,000 points, each of the sectors of the optical positioning sensor (PSD) stores 25M data, and 4 sectors, so 100M data can be stored. Reading them in order is the first step in analysis and restoration.

<2. Optical Position Sensor (PSD) Position Value Calculation>

As shown in FIG. 9, if the four sector values A, B, C, and D are read and the diameter of the beam is known, the center of the beam is positioned at the top, bottom, left, and right positions of the optical position sensor PSD. It can be calculated whether it has reached.

Since the four sectors of the optical position sensor (PSD) are divided in the up, down, left and right directions, if the light distribution is uniform, the sector in the direction where the light beam is located according to the position of the light beam receives more light than the opposite direction. And as a result, you have a larger number of data. Therefore, the center position of the light beam can be known by comparing the difference in the amount of light in the up, down, left and right sectors.

However, if the intensity of the total light amount is large, the difference in the up, down, left, and right light amounts becomes larger in proportion to the greater intensity of the total light amount, even if the positions of the light beams are the same as compared with the case where the total light intensity is small. In order to prevent crosstalk, the difference between the upper, lower, left, and right light amounts is divided by the size of the total light amounts and normalized.

In addition, if the width of the light beam is large, even if the position of the light beam is the same as compared with the light beam width, the difference in the amount of light up, down, left and right becomes smaller in inverse proportion to the width of the light beam. To prevent this, multiply the difference between the top, bottom, left, and right amounts of light by half the size of the beam, and the distance is used.The size of the beam used here does not change depending on the condition of the specimen. use.

As a result, as shown in Equation 5 below, by dividing the total light quantity by the difference in the light quantity of up, down, left and right and multiplying by half the size of the light beam, it is calculated where the light beam is located up, down, left, or right of the optical position sensor (PSD) sensor. You can do it.

<3. Calculating the Surface Slope Value of the Subject>

Since the up-down, left-right position value of the optical position sensor PSD is changed according to the slope of the local region of the object under test, knowing the top-down, left-right position value of the optical position sensor PSD has a local area slope of the test object surface. Can be inverted.

For example, as shown in FIG. 10, if the distance from the surface of the object to the effective surface of the lens is l and the local area slope of the surface of the object is θ, the angle of the reflected light reflected from the surface of the object is determined. 2θ, which is twice the inclination of the local region of, and when the reflection angle proceeds to the effective surface of the lens, the separation distance of tan (2θ), the tangent of angle 2θ, and tan (2θ) xl, which is the product of the distance l, compared to the non-tilted reflected light. Has Therefore, as shown in Equation 6 below, when θ is a very small angle, tan (2θ) xl (2θ x l can be approximated.

The separation distance thus obtained is equal to the up-down, left-right position calculated from the optical position measurement sensor (PSD) measurement data, so that 2l, which is twice the distance, is divided by the up-down-left-right position, thereby providing a local inclination value θ on the surface of the inspection object. It can be obtained as shown in Equation 7 below.

The up, down, left, and right positions calculated from the optical position sensor (PSD) measurement data can obtain two values of up, down, left, and right. Thus, the inclination of the surface of the inspection object and the inclination of the front, back, left, and right directions are obtained. do.

<4. Calculate the surface height of the object>

The inclination of the front-back, left-right direction along the local area | region of the to-be-tested object surface was obtained by the method mentioned above. As shown in FIG. 11, the obtained tilt value in the front, rear, left, and right directions includes a plurality of front and rear direction lines connecting the local region of the inspection object front and back and a plurality of left and right direction lines connecting the left and right, and also the local region in the front and rear direction. There is a slope value and a slope value in the left and right directions.

Each line in the front and rear direction is composed of a plurality of points. The height is a continuous connection value of the slope, and the product of the slope and the distance is the difference of the heights. The height difference between the points in the front-back direction can be calculated, and by performing this process at the points of the entire line, the height shape of one line can be obtained.

This process may be performed in all of the plurality of lines existing in the front and rear directions, and may also be performed in all of the plurality of lines using the left and right direction inclination values and the point spacing in the left and right lines, respectively.

As a result of performing this process, a height shape in each line in the front and rear or left and right directions can be obtained, and each of the plurality of lines in the front and rear directions and the left and right directions may be discontinuous. This discontinuity can be continuously connected by mixing the front and rear and left and right directions.

For example, after obtaining a height shape in a plurality of lines existing in the front-back direction, there may be a discontinuous height difference between the plurality of lines, which becomes discontinuous only in the left-right direction. However, since a plurality of lines existing in the left and right directions are not discontinuous in the left and right directions, an integral constant technique for applying the height values of the front and back lines to the height shape of the left and right lines is applied.

<5. Planar Height Function Flattening of Inspection Object>

The result of the above-described process for calculating the surface height value of the inspected object is a three-dimensional curved surface as the height shape of the surface of the inspected object. However, this three-dimensional curved surface may have a contour shape that may or may not actually exist depending on the settings of the device and the response of the measurement system.

In fact, the contour shape exists when the overall shape is inclined. This is a result of the fixed state of the inspection object not being set to be completely flat with respect to the measurement system. When the relative height is greater than the height difference, the scale value of the height at the time of observation is made large, so that it is difficult to observe small irregularities.

Therefore, in order to remove this, by obtaining the inclined contour shape from the height data of the result and removing it, it is possible to observe the uneven shape of the inspected object.

In addition, the wavelet filtering technique is applied to remove contours or noises that do not actually exist, thereby leaving only the uneven shape of the inspected object of interest.

<6. Profiling Result>

After the planarization process described above, the result appears in the shape of a flattened three-dimensional curved surface. By the way, a user who measures the three-dimensional shape of the inspected object often needs a shape represented by a two-dimensional curve rather than a three-dimensional curved shape. This represents a cross section in a certain section with respect to the three-dimensional curved shape. As shown in FIG. 12, a section to be observed by the user is designated, and data about a curve that is a cross section in the designated section is selected from the surfaces. It is represented by a curve. This series of tasks is called profiling.

In the curve data of the profiled section, detailed statistical data on the surface condition such as the maximum, minimum, average, standard deviation, and roughness of the height are aggregated and monitored together with the user, thereby reducing the user's working time and complexity. The results for the shape data can be summarized into a few simple aggregated numerical results.

The analyzed data is expressed in the form of line analysis, surface analysis, and 3D analysis in a form that is easy for the user to understand. Line analysis is useful for identifying the precise shape of a given location line, and surface analysis provides an image as if it were viewed from the top down. In addition, the 3D analysis provides a specific area of the surface analysis in a three-dimensional solid form, and the 3D analysis provides an image filtered data according to the frequency.

As described above, the apparatus and method for measuring a three-dimensional surface shape according to the present invention and the system by using a telecentric F-Theta lens as a lens of the three-dimensional surface shape measuring device, while focusing vertically on the subject to be inspected at equal intervals It is possible to scan linearly and to minimize the measuring distance between the measuring device and the inspected object to provide a miniaturized measuring device.

In addition, the apparatus and method for measuring the three-dimensional surface shape according to the present invention and its system improve the uniformity of scanning by using a high-speed rotating mirror, and dramatically improve the surface measurement speed of the inspected object by using DAQ together with the high-speed rotating mirror. Let's do it.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

1 is a main configuration diagram of an optical unit of a three-dimensional surface shape measuring apparatus according to the present invention;

Figure 2 is a perspective view of the upper plate of the three-dimensional surface shape measuring apparatus according to the present invention,

3 is an internal perspective view of a three-dimensional surface shape measuring apparatus according to the present invention;

4 is an external perspective view of a three-dimensional surface shape measuring apparatus according to the present invention,

5 is a perspective view of a three-dimensional surface shape measurement system according to the present invention,

6 is a block diagram of a three-dimensional surface shape measurement system according to the present invention;

7 is a control flowchart showing a three-dimensional surface shape measuring method according to the present invention;

8 is a view showing a data measurement value storage process of the optical position sensor according to the three-dimensional surface shape measurement method of the present invention,

9 is a view showing a light position calculation process of the optical position sensor according to the three-dimensional surface shape measurement method of the present invention,

10 is a view showing a process of calculating the slope of the surface according to the three-dimensional surface shape measurement method of the present invention,

11 is a view showing a process of calculating the height of the surface according to the three-dimensional surface shape measurement method of the present invention,

12 is a view showing a three-dimensional surface shape measurement results according to the present invention on a display device.

Claims (8)

In the three-dimensional surface shape measuring apparatus, A light source for irradiating a laser light to the surface of the inspected object whose shape of the three-dimensional surface is to be measured; A rotating mirror which rotates at a constant speed and deflects the laser light irradiated from the light source and the laser light reflected from the inspected object; The laser beam deflected from the rotating mirror is incident on the surface of the inspected object vertically, and the laser beam moving according to the rotation angle of the rotating mirror is moved along the surface of the inspected object in a straight line to scan the surface of the inspected object. A telecentric F-Theta lens for converging laser light reflected from the scanned object; An optical position sensor for receiving a laser beam reflected from the inspected object and deflected from the rotating mirror to measure a deflection degree of the received laser beam; And A semi-reflecting mirror which reflects the laser light of the light source to the rotation mirror, and is reflected from the inspected object to transmit the laser beam deflected from the rotation mirror to be incident on the optical position sensor; . The method of claim 1, A loading unit for loading the inspected object into a measurement position; A stage for aligning the inspected object mounted to the loading unit; A camera for photographing the entire state of the inspected object mounted on the loading unit; And 3D surface shape measuring apparatus further comprises a; distance measuring device for measuring the height and horizontality of the test object. The method of claim 1, And a synchronization sensor for capturing a time point at which the optical position measurement sensor measures the incident laser light and controlling synchronization of the optical position measurement time point of the optical position measurement sensor. In the three-dimensional surface shape measurement method, Loading the test object into the loading unit; Photographing the entire state of the loaded test object; Aligning the loading unit with a test position of the test object; Measuring a three-dimensional surface of the aligned test object; Collecting and storing three-dimensional surface data of the measured object; Analyzing the stored data; And And displaying the three-dimensional surface shape of the inspected object in accordance with the analyzed data. The method of claim 4, wherein before measuring the three-dimensional surface of the aligned test object, Measuring a horizontal degree of the inspected object; Adjusting the horizontal level of the inspected object according to the measured horizontality; Performing initial scanning on the horizontally adjusted inspected object; And And precisely adjusting the position of the inspected object according to the initial scanning result. 3. The method of claim 3, further comprising performing an initialization process. In the three-dimensional surface shape measurement system, A light source for irradiating a laser light to the surface of the object to be measured, wherein the shape of the three-dimensional surface is to be measured; a rotating mirror for deflecting the laser light irradiated from the light source and the laser light reflected from the object to be rotated at a constant speed; The laser beam deflected from the foreground is incident on the surface of the test object vertically, and the laser light spot moving according to the rotation angle of the rotating mirror is moved along the surface of the test object in a straight line to scan the surface of the test object. And a telecentric F-Theta lens for converging laser light reflected from the scanned object, and receiving laser light reflected from the object to be deflected from the rotating mirror to deflect the received laser light. An optical position sensor for measuring a degree, and a laser beam of the light source is reflected by the rotating mirror, It is reflected by the object optical part including a half mirror, which was transmitted through the deflected laser beam from the rotating view to be incident to the optical position sensor; A loading unit for loading the inspected object to a measurement position, a stage for aligning the inspected object mounted on the loading unit, a camera for photographing the entire state of the inspected object mounted on the loading unit, and the inspected object An adjusting unit including a range finder for measuring a horizontal level of the; And A motion board for controlling driving of the loading unit and the stage, a DAQ storing data measured at high speed from the optical unit, a storage unit storing data applied from the DAQ, the optical unit, an adjusting unit, and a motion 3D surface shape measurement system comprising a; central processing unit including a control unit for controlling the operation of the board, DAQ and storage. The method of claim 6, wherein the optical unit, And a synchronization sensor for capturing a time point at which the optical position measurement sensor measures an incident laser light and controlling synchronization of the optical position measurement time point of the optical position measurement sensor. The method of claim 7, wherein the stage, An XYZ stage for aligning the inspection position of the inspected object by moving the loading part back, forth, left, and right; A tilt stage for adjusting the inclination of the inspection position horizontally by adjusting the inclination of the loading part; And a six-axis stage including a rotation stage for rotating the loading unit to align the inspection positions of the inspection object.

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