KR20080027757A - Method for measuring three dimension shape using multiple interferometry - Google Patents

Abstract

A method for measuring the three dimensional shape of a target object is provided to precisely measure the three dimensional shape by automatically controlling a focus according to a reflection characteristic of the target object. A method for measuring the three dimensional shape of a target object comprises the steps of transferring the target object to an inspection position(S110), selecting a measurement mode for the target object(S120), checking whether the selected measurement mode is a Moire interferometry measurement mode(S130), adjusting the focus of a camera(S140), and calculating a first height map and a first low visibility of the target object(S150). If the selected measurement mode is a coaxial photo interferometry mode, the focus of the camera is adjusted by controlling an objective lens unit(S160) and a second height map and a second low visibility of the target object are calculated(S170). A controller calculates a height distribution based on the first and second height maps and first and second low visibilities, thereby deciding whether the target object has a defect(S180).

Description

Method for Measuring Three Dimension Shape Using Multiple Interferometry

The present invention relates to a three-dimensional shape measurement method using a multi-interferometer, and more specifically, a multi-interferometer capable of measuring a three-dimensional shape by using a side moiré interferometer and a coaxial optical interferometer for an inspection object in which diffuse reflection or specular reflection occurs. It relates to a three-dimensional shape measurement method using.

The three-dimensional shape system is composed of a transfer table, a projection unit, an acquisition unit and an image processing unit. A method of measuring a three-dimensional shape of an inspection object by using a three-dimensional shape system having such a configuration will be described as follows.

In order to measure the three-dimensional shape of the inspection object, the reference phase corresponding to the reference plane is calculated. The reference phase is a reference plane used to measure the three-dimensional shape of the inspection object to project the grid pattern laterally to the reference plane through a light source, a projection grid, and a projection lens constituting the projection unit. In order to apply the N-bucket algorithm when projecting the grid pattern on the reference plane, the projection lattice is projected to the reference plane with a small transfer to a driving device such as PZT (piezoelectric), and the grid pattern image reflected from the reference plane is Image is captured by the camera and transmitted to the image board of the image processor. When the grid pattern image is transmitted from the image processor, the N-bucket algorithm is applied to obtain a reference phase with respect to the reference plane.

When the reference phase corresponding to the reference plane is obtained, the phase of the inspection object is acquired. The inspection object is transferred to the inspection position by the transfer table, and when the inspection object is transferred to the inspection position, the projection is projected to the side of the inspection object in the same manner as the projection of the grid pattern to the reference plane. In order to apply the N-bucket algorithm to project the grid pattern, the grid pattern is projected onto the measurement surface while the grid is micro-transmitted through the driver, and the grid pattern image reflected from the measurement surface is captured by the camera of the acquisition unit and transmitted to the image processing unit. do. The image processor obtains the object phase of the inspection object by applying a bucket algorithm to the transmitted grid pattern image.

When the reference phase and the object phase are obtained, the moiré phase is obtained by subtracting the object phase from the reference phase. When the moiré phase is obtained, the height information of the object is calculated using the obtained moiré phase to measure the three-dimensional shape of the object.

When measuring the three-dimensional shape of the inspection object by using the three-dimensional shape system configured as in the prior art and the projection of the grid pattern on the side of the inspection object after taking the image of the grid pattern formed on the inspection object, the image of the grid pattern image When measuring the height of the inspection object by using a mirror reflecting surface, such as a mirror or glass surface does not form a grid pattern image on the inspection object there is a problem that can not accurately measure the three-dimensional shape of the inspection object.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and in the case of an inspection object in which diffuse reflection or specular reflection occurs, a multi-interferometer capable of measuring a three-dimensional shape by using a side moiré interferometer and a coaxial optical interferometer as an inspection object It is to provide a three-dimensional shape measurement method used.

Another object of the present invention is to provide a three-dimensional shape measuring method using a multi-interferometer that can automatically adjust the focus when measuring the three-dimensional shape of the inspection object.

The three-dimensional shape measuring method using the multi-interferometer of the present invention includes the steps of transferring the inspection object to the inspection position by the work stage, and if the inspection object is transferred to the inspection position, the central control unit to select the measurement mode of the inspection object, When the measurement mode is selected, the central controller determines whether the selected measurement mode is a side moiré interferometer measurement, and when the side moire interferometer measurement is selected, the central controller controls the filter controller and the objective lens controller of the module controller to turn on the block filter. And adjusting the focus of the camera according to the side moiré interferometer by setting the passband filters of the first and third filter elements and adjusting the objective lens unit using the focus detection signal output from the focus detection unit. When the on, setting of the first and third filter elements and adjusting the focus of the camera are completed, the central controller Moiré interferometer measurement by controlling the module control unit, the imaging unit and the grid pattern pattern projection unit, respectively, and calculating the first height map and the first low visibility region of the inspection object by using the reflected image obtained by the side moiré interferometer measurement If the side moiré interferometer is not measured in the process of confirming that the side moiré interferometer is measured, the central controller controls the filter controller and the objective lens controller of the module controller to turn off the block filter, respectively, and passes the filter of the first and second filter elements. Adjusting the objective lens unit using the focus detection signal output from the focus detection unit and adjusting the focus of the camera according to the coaxial optical interferometer measurement, turning off the block filter and passing the first and second filter elements. After the band filter setting and focus adjustment of the camera are completed, the central controller controls the module controller, the imaging unit, the coaxial lighting unit, Calculating the second height map and the second low visibility region of the inspection object according to the coaxial optical interferometer measurement by using the reflected image acquired for the coaxial optical interferometer measurement by controlling the plane generating units respectively; When the first height map and the first low visibility area are calculated and the second height map and the second low visibility area are calculated, the central control unit calculates the complementary height map and calculates the height distribution information of the object to be inspected. Characterized in that it comprises a step of determining whether or not defective.

The three-dimensional shape measuring method using the multi-interferometer of the present invention has the advantage of measuring the three-dimensional shape of the test object more precisely or accurately by using a side moiré interferometer and a coaxial optical interferometer on the test object where diffuse reflection or specular reflection occurs. It provides an advantage that the focus can be automatically adjusted according to the reflection characteristics of the inspection object when measuring the three-dimensional shape of the inspection object.

(Example)

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a perspective view showing the configuration of a three-dimensional shape measurement system using a multi-interferometer of the present invention, Figure 2 is a plan view of a three-dimensional shape measurement system using a multi-interferometer shown in Figure 1, Figure 3 is shown in Figure 2 4 is a cross-sectional view of the I-I line cross-sectional configuration of the three-dimensional shape measurement system using a multi-interferometer, Figure 4 is a diagram showing a cross-sectional structure of line II-II of a three-dimensional shape measurement system using a multi-interferometer shown in FIG. .

As shown, the three-dimensional shape measurement system using the multi-interferometer of the present invention is measured by using a side moiré interferometer when the region of interest of the inspection object (1) is diffuse reflection, coaxial light when mirror reflection occurs In order to measure the region of interest of the inspection object 1 using an interferometer, the imaging unit 10, the coaxial illumination unit 20, the reference plane generating unit 30, and the focus detection unit 50 respectively have a surface of the work stage 2. It is installed to be perpendicular to the, the grid pattern projection portion 40 is configured to be inclined. The imaging unit 10, the coaxial lighting unit 20, the reference plane generating unit 30, the grid pattern pattern projecting unit 40, the focus detecting unit 50, and the system control unit 60, 70, 80, 90 having such an installation configuration When the configuration of) is sequentially described as follows.

1 to 4, the imaging unit 10 is reflected by the inspection object 1 transported by the work stage 2 (the work stage 2 is applied to the XY table) and transported to the inspection position as shown in FIGS. The camera 11, the imaging lens 12, the first filter element 13, the first light splitter 14, the circular lamp 15, the lens unit 16 to capture the reflected image and The third light splitter 17 is configured.

The camera 11 captures a reflection image reflected from the inspection object 1, and the imaging lens 12 receives the reflection image reflected from the inspection object 1 and irradiates the camera 11 to the camera 11. Is installed on the lower side. A first filter element 13 is installed below the imaging lens 12 to filter the reflected image reflected from the inspection object 1 and transmit the filtered image to the imaging lens 12, and below the first filter element 13. The first light splitter 14 is installed. The first light splitter 14 changes the light path to irradiate the test object 1 with the white light irradiated to the coaxial light unit 20. A circular lamp 15 is installed below the first light splitter 14 that changes the light path so that the white light is irradiated onto the inspection object 1.

The circular lamp 15 is installed under the first light splitter 14 to generate lamp illumination to the inspection object 1 to adjust the focus of the camera 11 or to measure the two-dimensional shape of the inspection object 1. The objective lens unit 16 irradiates the white light, which is divided into the changed light paths in the first light splitter 14, and irradiates to the inspection object 1 or the reflection image reflected from the inspection object 1 to the camera. In order to irradiate with (11) it is installed to be movable below the circular lamp (15).

The third light splitter 17 is installed below the objective lens unit 16. The third light splitter 17 splits the white light and irradiates the inspection object 1 with the reference object or irradiates with the reference mirror to irradiate the reflection image reflected from the inspection object 1 and the reflection image reflected from the reference mirror with the first filter. The element 13 is irradiated.

In the above configuration, the objective lens unit 16 includes the objective lens transfer mechanism 16a, the objective lens mounting member 16b, and a plurality of objective lenses 16c, 16d, and 16e having different magnifications as shown in FIG. It is composed of A plurality of objective lenses 16c, 16d, and 16e having different magnifications are provided in the objective lens mounting member 16b. The objective lens transfer mechanism 16a is installed at one side of the objective lens mounting member 16b to rack and pinion and ball screws to transfer the objective lenses 16c, 16d, and 16e in the horizontal and vertical directions. ball screws or linear motors. The objective lens transfer mechanism 16a to which the various linear transfer mechanisms are applied transfers the objective lenses 16c, 16d, and 16e in the horizontal direction under the control of the objective lens controller 75 of the module controller 70. 16c, 16d, and 16e are aligned with the lower side of the imaging unit 10, or the objective lenses 16c, 16d, and 16e are moved up and down in the vertical direction so that the focus of the camera 11 can be automatically adjusted.

When the focus of the objective lens unit 16 of the imaging unit 10 is adjusted, the imaging unit 10 irradiates the white light to the inspection object 1 so that the reflected image may be captured for the coaxial optical interferometer measurement. As shown in FIGS. 1, 2 and 4, the coaxial lighting unit 20 for irradiating white light is installed on one side of the first direction Y of the imaging unit 10, and the first lighting element 21, The first condenser lens 22, the second filter element 23, the second condenser lens 24, and the reflection mirror 25 are provided.

The first lighting device 21 generates a white light by applying a halogen lamp, a xenon lamp or an LED lamp. The first condenser lens 22 is disposed below the first illuminating device 21 to condense and irradiate white light generated by the first illuminating device 21. A second filter element 23 is disposed below the first condenser lens 22 to filter and transmit white light that has been collected by the first condenser lens 22 and then irradiated. A second condenser lens 24 is installed below the second filter element 23 to condense and irradiate the filtered white light, and a second condenser lens 24 is condensed below the second condenser lens 24. After the reflection mirror 25 is installed to reflect the white light is irradiated. The reflective mirror 25 transmits the white light emitted from the second condenser lens 24 to the third light beam of the imaging unit 10 after passing through the second light splitter 51 when the focus detecting unit 50 is installed. The divider 17 reflects the inspection object 1 or the reference plane generator 30 so that it can be irradiated.

The reference plane generator 30 is provided on the other side of the first direction Y of the imaging unit 10 so as to irradiate the imaging unit 10 with the reflected image in which white light is irradiated onto the inspection object 1. The reference plane generator 30 includes a block filter 31, a block filter transfer mechanism 31a, a reference mirror 32, and a mirror transfer mechanism 32a as shown in FIGS. It consists of. One side of the block filter 31 is provided with a block filter transfer mechanism 31a controlled by the filter controller 73 of the module control unit 70. The block filter transfer mechanism 31a is shown to raise / lower the block filter 31 in the direction perpendicular to the arrow direction shown in FIG. 4, but this is an example for explaining the transfer of the block filter 31 and the horizontal direction. That is, it can also be installed in the direction passing through the drawing of FIG.

The block filter 31, which is transported by the block filter transfer mechanism 31a and turned on / off, is turned on (block filter) so that the block filter 31 is not positioned on the front surface of the reference mirror 32 or vice versa. When the reference numeral 31 is located in front of the reference mirror 32, the inspection object may be adjusted by adjusting the focus of the camera 11 of the moiré interferometer or filtering or absorbing the coaxial light incident on the reference mirror 32. The three-dimensional shape according to the diffuse reflection of 1) can be measured. On the contrary, when the block filter 31 is turned off, the inspection object may be adjusted by adjusting the focus of the camera 11 of the coaxial interferometer or reflecting the reflection image reflected from the reference mirror 32 and the reflection image according to the specular reflection to the camera 11. The three-dimensional shape according to the specular reflection of (1) can be measured. That is, in the state in which the block filter 31 is not located at the front side, the reference mirror 32 reflects the light irradiated to the inspection object 1 from the white light and reflects the light reflected back through the reference mirror 32. The camera 11 may capture an image through the third light splitter 17.

The reference mirror 32 for irradiating and reflecting the white light irradiated to the inspection object (1) is irradiated by the mirror transfer mechanism (32a) installed on one side within the scanning range, that is, the transfer distance of the reference mirror (32) Star will be transported. When the reference mirror 32 is transferred to the mirror transfer mechanism 32a controlled by the reference mirror controller 74 of the module control unit 70 step by step within the scanning range, the imaging unit 10 at every transfer. In the camera 11 of the image to reflect the white light. When the reflection image is captured every time the reference mirror 32 is transferred, the central controller 60 measures the three-dimensional shape of the inspection object 1 in which specular reflection occurs.

In addition to the measurement of the coaxial optical interferometer according to the white light, the grid pattern pattern projection unit 40 is provided for the measurement of the side moiré interferometer for measuring the inspection object (1) in which diffuse reflection occurs.

As shown in FIGS. 1, 2, and 3, the grid pattern pattern projection unit 40 is installed at one side and the other side of the second direction X of the image capturing unit 10, so that the reflection image is reflected from the inspection object 1. The grid pattern pattern light is irradiated onto the inspection object 1 so as to be reflected. The grid pattern pattern projection unit 40 which irradiates the grid pattern pattern lights to both sides of the inspection object 1 respectively has a second lighting element 41, a grid element 42, a grid transfer mechanism 42a, and a third light source. It consists of a condenser lens 43 and a third filter element 44.

The second lighting element 41 is composed of an illumination source 41a and condensing lenses 41b and 41c to generate illumination. When the illumination is generated in the second lighting element 41, the grid pattern pattern illumination is generated by the grid element 42 provided below the second lighting element 41. The grating element 42 generating the grid pattern pattern illumination is driven to be finely fed by the grating transfer mechanism 42a provided on one side, and the grating transfer mechanism 42a is applied to a PZT (Piezoelectric) transfer mechanism or fine linear transfer. The mechanism is applied) is controlled by the grid controller 72 of the module control unit 70 to transfer the grid element 42. The grating element 42 is transferred N times by the grating transfer mechanism 42a to measure the side moiré interferometer, and the camera 11 of the imaging unit 10 receives the reflected image reflected from the inspection object 1 for each transfer. The image is taken.

In order to allow the camera 11 to capture a reflection image according to the grid pattern pattern light, when the grid pattern pattern light is generated in the grid element 42, the grid element 42 may be collected and irradiated to the inspection object 1. ), A third condensing lens 43 is provided below. A third filter element 44 is installed below the third condenser lens 43 to filter the grid pattern pattern light emitted from the third condenser lens 43 and to irradiate the object to be examined 1. As described above, the first to third filter elements 13, 23, and 44 which filter the grid pattern pattern light or filter the white light or the reflected image are irradiated with each other, as shown in FIG. 5. It consists of a plurality of filters 4a, 4b, 4c and 4d having different frequency passbands and filter rotor spheres 13a, 23a and 44a.

The filter mounting member 3b is provided with filters 4a, 4b, 4c, and 4d having at least one different pass band, and the filter mounting member 3b is rotated at one side of the filter mounting member 3b. Filter rotation mechanisms (13a, 23a, 44a) are rotated about the rotation axis (r1) to rotate about the center. The filter rotating mechanisms 13a, 23a, and 44a are controlled by the filter controller 73 of the module control unit 70, so that the alignment shaft a1 of the filter 4a provided on the filter mounting member 3b has an image forming lens 12. The first condenser lens 22 or the third condenser lens 43 is aligned and rotated to replace the filter 4a. In order to replace the pass band with the filter 4a, the filter rotating mechanisms 13a, 23a, 44a and the filter mounting member 3b are connected to the belt 3a as shown in FIG. 5 or directly engaged using a gear. Can be.

When the grid pattern pattern light is filtered through the third filter element 44 and irradiated to the inspection object 1, the camera 11 captures a reflection image reflected from the inspection object 1. When the camera 11 captures the reflected image reflected from the inspection object 1 N times by using the grid pattern pattern illumination irradiated through the third filter element 44, the central controller 60 captures the N reflected images. It is possible to measure the three-dimensional shape of the inspection object (1) to be diffusely reflected.

Coaxial with the imaging unit 10 as shown in FIGS. 1, 2 and 4 to automatically adjust the focus of the camera 11 when measuring the three-dimensional shape of the inspection object 1 in which diffuse reflection or specular reflection occurs. The focus detecting unit 50 is installed between the lighting units 20 to detect the focus of the imaging unit 10. In order to detect the focus of the imaging unit 10, that is, the camera 11, the focus detecting unit 50 includes a second light splitter 51, a fourth condenser lens 52, and a pin hole unit 53. And a light receiving element unit 54.

The second light splitter 51 is installed on the lower side of the focus detecting unit 50 to reflect the reflected image from the inspection object 1 (here, the reflected image is a lamp illumination generated by the circular lamp 15, the grid pattern pattern projection The white light generated by the negative or coaxial illumination unit is irradiated by being irradiated to the inspection object (1), and is irradiated. The fourth condenser lens 52 irradiates the reflected image irradiated from the second light splitter 51. It is installed on the upper side of the second light splitter 51 to focus and irradiate. The pinhole unit 53 is provided on the upper side of the fourth condenser lens 52 provided on the upper side of the second light splitter 51. The pinhole unit 53 transmits the reflected image collected and irradiated through the fourth condenser lens 52 through the pinhole 53b. The light receiving element unit 54 is installed on the upper side of the pinhole unit 53 to generate a focus detection signal by converting the reflected image transmitted through the pinhole 53b into an electrical signal.

As shown in FIG. 7A, in the light receiving element unit 54, a plurality of light receiving elements 54b are arranged and installed in the light receiving element installation member 54a at positions corresponding to the arrangement of the pinholes 53b. As shown in FIG. 7B, a plurality of pin holes 53b are arranged in the pin hole forming member 53a. As described above, the reflected image transmitted through the plurality of pinholes 53b is irradiated to the plurality of light receiving elements 54b, respectively. When the reflected image is irradiated to the plurality of light receiving elements 54b, each of the light receiving elements 54b converts the detected reflected image into an electrical signal to generate a plurality of focus detection signals, and converts the generated focus detection signals into a focus signal acquisition unit. Obtained at 90. The focus signal acquisition unit 90 converts the focus detection signal into a digital signal and transmits it to the central control unit 60. The central controller 60 generates an objective lens control signal when the central controller 60 does not match the previously stored focus information by using the transmitted focus detection signal. When the objective lens control signal is generated in the central controller 60, it is received by the objective lens controller 75 of the module controller 70 to drive the objective lens transfer mechanism 16a to transfer the objective lens unit 16 to the camera ( 11) to adjust the focus.

The work stage 2 and the image pickup unit 10 receive a focus detection signal output from the light receiving element unit 54 of the focus detection unit 50 to adjust the focus, and drive the objective lens transfer mechanism 61a. And system control unit (60, 70, 80, 90) is provided for overall control of the coaxial lighting unit 20, the reference plane generator 30 and the grid pattern pattern projection unit (40). The system controller 60, 70, 80, 90 receives the focus detection signal output from the focus sensing unit 50 and controls the focus of the imaging unit 10, that is, the camera 11, and the grid pattern projection unit 40. ) And the coaxial illumination unit 20 are irradiated with the grid pattern pattern illumination and the white illumination with the inspection object 1 respectively, and when the reflection image is acquired by the imaging unit 10, it is received and received the three-dimensional shape of the inspection object 1. Will be measured.

In order to measure the three-dimensional shape of the inspection object 1, a system control unit 60, 70, 80, 90 for controlling the three-dimensional shape measurement system using the multi-interferometer of the present invention is shown in FIGS. As described above, the control unit includes a central controller 60, a module controller 70, an image acquisition unit 80, and a focus signal acquisition unit 90.

Among the system controllers 60, 70, 80, and 90, the focus signal acquisition unit 90 receives the focus detection signal output from the light receiving element unit 54, converts the signal into a digital signal, and outputs the digital signal to the central controller 60. The central controller 60 can recognize whether the focus of the camera 11 is adjusted, and the image acquisition unit 80 receives the reflected image captured by the camera 11 and processes the reflected image into a digital signal to reflect the reflected image signal. Is output to the central control unit 60.

The image acquisition unit 80, the focus signal acquisition unit 90, the imaging unit 10, the reference plane generator 30, and the grid pattern to generate the focus detection signal or the reflected image signal output to the central control unit 60. The module control unit 70 controls the projection unit 40 and the like. The module controller 70 receives the first to third lighting signals, the grid control signal, the filter control signal, the mirror control signal, and the objective lens control signal respectively output from the central controller 60, and receives the circular lamp 15 and the first lamp. And the second lighting elements 21 and 41, the lattice transfer mechanism 42a, the first to third filter elements 13, 23 and 44, the block filter transfer mechanism 31a and the objective lens transfer mechanism 16a, respectively. Control. In addition, the module controller 70 controls the stage transfer mechanism 2a through the stage controller 76 to transfer the inspection object 1 located on the work stage 2 to the inspection position. In this case, the inspection position indicates an area to be measured of the inspection object 1, that is, an area in which the imaging unit 10 is positioned above the measurement region of interest.

The module controller 70 for transferring the inspection object 1 to the inspection position and measuring the transported inspection object 1 includes an illumination controller 71, a grid controller 72, a filter controller 73, and a reference mirror controller ( 74), the objective lens controller 75 and the stage controller 76.

The stage controller 76 controls the drive of the stage transfer mechanism 2a to transfer the work stage 2. By the transfer of the work stage 2, the inspection object 1 can be transferred to the inspection position. When the inspection object 1 is transferred to the inspection position, in order to measure the three-dimensional shape of the inspection object 1, the lighting controller 71 receives the first to third illumination signals output from the central control unit 60 and receives a circular shape. The lamp 15, the first illumination element 21 and the second illumination element 41 are controlled respectively to generate grid pattern pattern illumination, white illumination or illumination applied for two-dimensional inspection or focus inspection. When the grid pattern pattern light is generated in the second lighting element 41, the grid controller 72 receives the grid control signal from the central controller 60 to control the grid transfer mechanism 42a to finely drive the grid element 42. That is, it moves so that the grid pattern pattern light can be irradiated to the inspection object (1).

The filter controller 73 receives the filter control signal output from the central controller 60 and controls the first to third filter elements 13, 23, and 44 and the block filter transfer mechanism 31 a to provide different pass bands. Any one of the filters 4a, 4b, 4c, and 4d having it is selected and replaced. The filters 4a, 4b, 4c, and 4d are replaced, and when measuring the coaxial optical interferometer, the reference mirror controller 74 receives the mirror control signal output from the central controller 60 to control the mirror transfer mechanism 32a. The reference mirror 32 is transported step by step in the scanning range to irradiate the white light to the inspection object (1) to measure the specular reflection of the inspection object (1). The objective lens controller 75 outputs the objective lens control signal output from the central controller 60 to automatically adjust the focus of the camera 11 of the image capturing unit 10 when measuring the specular or semi-reflected inspection object 1. Control the driving of the objective lens transfer mechanism 16a to adjust the focus of the camera 11 by moving the objective lens unit 16 up or down, or the objective lenses 16c and 16d previously set in the central controller 60. , 16e).

Replace the objective lenses 16c, 16d, 16e and replace the filters 4a, 4b, 4c, 4d to measure the three-dimensional shape of the mirror-reflected or diffusely-reflected inspection object 1, and finally The central control unit 60 to determine whether the defect is composed of an interface board 61, an image processing board 62 and a control board 63. The control board 63 generates the first to third lighting signals, the grid control signal, the filter control signal, the mirror control signal, and the object lens control signal, respectively, and transmits them to the module control unit 70 through the interface board 61. Receives the focus detection signal output from the focus signal acquisition unit 90 to generate an objective lens control signal for adjusting the focus of the camera 11, receives the inspection image received from the image acquisition unit 80 to inspect The three-dimensional shape of the object 1 is calculated to determine whether the inspection object 1 is defective.

The method for measuring the three-dimensional shape of the inspection object 1 using the three-dimensional shape measuring system using the multi-interferometer of the present invention configured as described above will be described with reference to the accompanying drawings.

8 is a flowchart illustrating a three-dimensional shape measuring method using a multi-interferometer according to the present invention. As shown in the drawing, the work object 2 in which diffuse reflection or specular reflection occurs is first inspected by the work stage 2 in order to measure a side moiré interferometer and a coaxial optical interferometer, that is, a white light scanning interferometer (WSI). A step (S110) of transferring the object 1 to the inspection position is carried out. When the inspection object 1 is transferred to the inspection position, the central controller 60 performs a step (S120) of selecting a measurement mode of the inspection object 1. When the measurement mode is selected, the central control unit 60 may set the order of the measurement mode in advance, that is, the side moiré interferometer is performed first, and then the coaxial optical interferometer may be set or the reverse order.

When the measurement mode is selected, the central controller 60 checks whether the selected measurement mode is a side moiré interferometer measurement (S130). As a result of the check, when the side moiré interferometer measurement is selected, the central controller 60 controls the filter controller 73 and the objective lens controller 75 of the module controller 70 to control the first and third filter elements 13 and 44, respectively. Set the passband filters 4a, 4b, 4c, and 4d, turn on the block filter 31, and use the focus detection signal of the inspection object 1 output from the focus detection unit 50 to 16) to adjust the focus of the camera 11 according to the side moiré interferometer measurement (S140). When the on of the block filter 31, the setting of the first and third filter elements 13 and 44, and the focus adjustment of the camera 11 are completed, the central controller 60 controls the module controller 70 and the imaging unit 10. And the grid pattern pattern projecting unit 40 are respectively controlled to measure the side moiré interferometer, and the first height map and the first low visibility region of the inspection object 1 are determined by using the reflection image obtained by the side moiré interferometer measurement. The calculating step (S150) is performed.

When the first height map and the first low visibility region of the inspection object 1 are calculated or checked in step S130, the central controller 60 may determine whether the first moiré interferometer is measured. The filter controller 73 and the objective lens controller 75 of 70 are controlled to set passband filters 4a, 4b, 4c, and 4d of the first and second filter elements 13 and 23, respectively, and a block filter. Step (S160) of adjusting the focus of the camera 11 according to the coaxial optical interferometer measurement by adjusting the objective lens unit 16 by using the focus detection signal output from the focus detection unit 50 by turning off 31. Conduct. When the block filter 31 is turned off, the first and second filter elements 13 and 23 pass band filters 4a, 4b, 4c and 4d are set, and the focus adjustment of the camera 11 is completed, the central control unit 60 is completed. ) Controls the module control unit 70, the imaging unit 10, the coaxial illumination unit 20, and the reference plane generator 30, respectively, to perform coaxial optical interferometer measurement and by using the reflected image acquired in the coaxial optical interferometer measurement. Computing the second height map and the second low visibility region of the inspection object 1 according to the coaxial optical interferometer measurement (S170).

When the first height map and the first low visibility area, the second height map and the second low visibility area are calculated in steps S150 and S170, the central controller 60 calculates the complementary height map and inspects the calculated height using the same. The height distribution information of the object 1 is calculated to determine whether the inspection object 1 is defective (S180).

The side moiré interferometer measurement process performed to calculate the height distribution information of the inspection object 1 to determine whether the inspection object 1 is defective will be described in more detail with reference to the accompanying drawings.

FIG. 9 is a detailed flowchart illustrating a method of measuring a side moiré interferometer shown in FIG. 8. As shown in FIG. 1, the filter 4a, 4b, 4c, 4d and the camera of the pass bands of the first and third filter elements 13 and 44 and the ON of the block 11, in step S140, the central controller 60 controls the filter controller 73 to pass through the first and third filter elements 13 and 44, respectively, in order to measure the side moiré interferometer. Step S141 is performed to set the filters 4a, 4b, 4c, and 4d.

When the block filter 31 is turned on and the first and third filter elements 13 and 44 are replaced with the pass band filters 4a, 4b, 4c, and 4d, respectively, the central controller 60 controls the objective lens controller ( Step 75 is performed to control the magnification of the objective lenses 16c, 16d, and 16e. When the magnifications of the objective lenses 16c, 16d, and 16e are set, the central controller 60 controls the illumination controller 71, the filter controller 73, the objective lens controller 75, and the focus signal acquisition unit 90, respectively. To activate the circular lamp 15, the first lighting device 21 or the second lighting device 41, and turn on the block filter 31 so that the focus detecting unit 50 receives the reflected light reflected from the inspection object 1; Receiving through the objective lens unit 16 is transferred to perform the step of adjusting the focus of the camera 11 (S143).

After the focus adjustment of the camera 11 according to the side moiré interferometer measurement is completed, the step of calculating the first height map and the first low visibility region of the inspection object 1 by using the reflected image acquired by the side moiré interferometer measurement First, in step S150, the central controller 60 checks whether the second lighting device 41 located on one side of the second direction X of the inspection object 1 is selected (S151). When the second lighting device 41 located on one side of the second direction X is selected, the central controller 60 may check the object to be inspected in the grid pattern projecting part 40 located on one side of the second direction X. After irradiating the grid pattern pattern with light, the reflection image reflected is calculated, the first phase map is calculated, the shadow and the saturation region are defined, and the grid pattern pattern projection unit 40 located at the other side of the second direction (X) is audited. After irradiating the grid pattern pattern light with the object 1, the reflected image is obtained, a second phase map is calculated, and a shadow and a saturated region are defined (S152).

The shadow and saturation regions are defined from the first phase map and the shadow and saturation regions are defined from the second phase map (S152) in more detail. First, when the second lighting element 41 located on one side of the second direction X is selected, the central controller 60 controls the lighting controller 71 according to the set brightness to locate the one side of the second direction X. The brightness of the second lighting device 41 is adjusted (S152a). When the brightness of the second lighting device 41 located on one side of the second direction X is adjusted, the central controller 60 controls the grid controller 72 to control the grid device 42 located on one side of the second direction X. ) Is transferred N times, and the reflected image is captured and stored by the camera 11 at every transfer (S152b). When the reflected image is stored, the central controller 60 extracts and stores the first average image from which the grid pattern is removed from the N reflected images (S152c). When the first average image is extracted, the central controller 60 calculates and stores the first phase map using the N-bucket algorithm (S152e). When the first phase map is calculated, the central controller 60 calculates and defines a shadow and a saturated region in the first phase map (S152e).

When the shadow and the saturation region are calculated in the first phase map, the central controller 60 checks whether the second lighting device located on the other side of the second direction X of the inspection object 1 is selected or not in the second direction (X). Adjusting the brightness of the second lighting device 41 located on the other side of the second direction X by controlling the lighting controller 71 according to the set brightness when the second lighting device 41 located on the other side of the (S152f) is performed. When the brightness of the second lighting device 41 located on the other side of the second direction X is adjusted, the central controller 60 controls the grid controller 72 to control the grid device 42 located on the other side of the second direction X. ) Is transferred N times, and the reflected image is captured and stored by the camera 11 at every transfer (S152g). When the reflected image is stored, the central controller 60 extracts and stores the second average image from which the grid pattern is removed from the N reflected images (S132h). When the second average image is extracted, the central controller 60 calculates and stores the second phase map using the N-bucket algorithm (S152i). When the second phase map is calculated, the central controller 60 calculates and defines a shadow and a saturated region in the second phase map (S152j).

When the shadow and the saturation region are defined from the first phase map and the shadow and the saturation region are defined from the second phase map through the above process, the central controller 60 determines the first and second phase maps from the shadow and the saturation region. A step S153 of calculating an integrated phase map and an integrated average image is performed. When the integrated phase map and the integrated average image are calculated, the central controller 60 calculates and defines the first height map and the first low visibility region using the integrated phase map and the integrated average image (S154).

Coaxial optical interferometer measurement is performed when the work to measure the inspection object 1 using the side moiré interferometer measurement is completed. For the coaxial optical interferometer measurement, first the off of the block filter 31 and the setting of the filters 4a, 4b, 4c, 4d in the pass band of the first and second filter elements 13 and 23 and the camera 11 In step S160, the central controller 60 controls the filter controller 73 so that the first and second filter elements 13 and 23 may pass through the filters 4a, 4b, 4c, respectively. 4d) is set (S161). When the block filter 31 is turned off and the first and second filter elements 13 and 23 are replaced with the pass band filters 4a, 4b, 4c, and 4d, respectively, the central controller 60 controls the objective lens controller ( Step 75 is performed to control the magnification of the objective lenses 16c, 16d, and 16e. When the magnification of the objective lenses 16c, 16d, and 16e is set, the central controller 60 controls the illumination controller 71, the filter controller 73, the objective lens controller 75, and the focus signal acquisition unit 90, respectively. The objective lens unit 16 receives the reflected light reflected from the inspection object 1 through the focus detecting unit 50 by activating the circular lamp 15 or the first lighting element 21 and turning off the block filter 31. In step S163, the camera 1 is moved to adjust the focus of the camera 1.

When the focus of the camera 11 according to the coaxial optical interferometer measurement is completed, in order to calculate the second height map and the second low visibility area of the inspection object 1, first, a reference mirror is performed by the central controller 60. In step S171, the scanning range 32 and the transfer step interval are set.

When the scanning range and the transfer step interval of the reference mirror 32 are set, the central controller 60 controls the illumination controller 71 according to the set brightness to adjust the brightness of the first lighting device 21 (S172). Conduct. When the first lighting device 21 is adjusted to the set brightness, the central controller 60 controls the reference mirror controller 74 to transfer the reference mirror 32 N times, and the reflected image from the camera 11 at each step transfer. Image capture, and obtaining and storing the captured reflection image (S173). When the N reflected images are stored, the central controller 60 calculates a brightness change for each step in each pixel (S174). When the change in the brightness of each step is calculated in each pixel, the central controller 60 calculates the height value and the second height map of the inspection object 1 located in the pixel (S175). When the height value and the second height map are calculated, the central controller 60 performs the step S176 of defining the second low visibility region from the height value and the second height map to complete the coaxial optical interferometer measurement.

When the first low visibility region and the second visibility region are defined through coaxial optical interferometer measurement or side moiré interferometer measurement, the complementary height map is calculated and the height distribution information of the inspection object is used to calculate the defect of the inspection object (1). It is determined whether or not (S180). In operation S180, when the first low visibility region and the second visibility region are calculated as illustrated in FIG. 11, the central controller 60 may use the first and second low visibility regions to complement each other. A step (S181) of calculating a low-view area is performed. When the third low visibility area is calculated, the central controller 60 calculates a third height map that can be complemented by using the first height map and the second height map (S182). When the third height map is calculated, the central control unit 60 calculates the height distribution information of the inspection object on the reference plane from the third height map (S183). When the height distribution information is calculated, the central control unit 60 calculates the volume, the representative height, and the eccentricity of the inspection object 1 from the height distribution information, and determines whether the inspection object 1 is defective based on this (S184). In this case, a three-dimensional shape can be measured by using a side moire interferometer and a coaxial optical interferometer for the inspection object 1 in which diffuse reflection or specular reflection occurs.

The three-dimensional shape measuring method using the multi-interferometer of the present invention can be applied to an apparatus for measuring the three-dimensional shape of the inspection object.

1 is a perspective view showing the configuration of a three-dimensional shape measurement system using a multi-interferometer of the present invention,

2 is a plan view of a three-dimensional shape measuring system using a multi-interferometer shown in FIG.

FIG. 3 is a cross-sectional view of the line I-I of the three-dimensional shape measuring system using the multi-interferometer shown in FIG.

4 is a cross-sectional view of line II-II of the three-dimensional shape measuring system using the multi-interferometer shown in FIG.

5 is a perspective view of the first to third filter elements shown in FIG.

6 is a perspective view of the objective lens unit shown in FIG.

7A and 7B are plan views showing in detail the configuration of the pinhole unit and the light receiving element unit shown in FIG. 4;

8 is a flow chart showing a three-dimensional shape measuring method using a multi-interferometer of the present invention,

9 is a flow chart showing in detail the method of measuring the side moiré interferometer shown in FIG. 8;

FIG. 10 is a flowchart showing the coaxial optical interferometer measuring method shown in FIG. 8 in detail. FIG.

FIG. 11 is a flowchart showing in detail a method of calculating the height distribution information and a method of determining whether there is a failure shown in FIG. 8; FIG.

Explanation of symbols on the main parts of the drawings

1: inspection object 2: work stage

10: imaging unit 20: coaxial lighting unit

30: reference plane generating portion 40: grid pattern pattern projection portion

50: focus detection unit 60: central control unit

70: module control unit 80: image acquisition unit

90: focus signal acquisition unit

Claims (7)

Transferring the inspection object to the inspection position by the work stage; Selecting, by the central controller, a measurement mode of the inspection object when the inspection object is transferred to the inspection position; If the measurement mode is selected, the central controller determines whether the selected measurement mode is the side moiré interferometer measurement; When the side moiré interferometer measurement is selected, the central controller turns on the block filter by controlling the filter controller and the objective lens controller of the module controller, respectively, and sets a pass band filter of the first and third filter elements, and outputs the focus from the focus detector. Adjusting the focus of the camera according to the measurement of the side moiré interferometer by adjusting the objective lens unit using the detection signal; When the on of the block filter and the setting of the first and third filter elements and the adjustment of the focus of the camera are completed, the central controller performs moiré interferometer measurement by controlling the module control unit, the imaging unit, and the lattice pattern projection unit, respectively, and measure the side moiré interferometer. Calculating a first height map and a first low visibility region of the inspection object by using the reflection image obtained by If the side moiré interferometer is not measured in the process of checking whether the side moiré interferometer is measured, the central controller controls the filter controller and the objective lens controller of the module controller, respectively, to turn off the block filter, and to set pass-pass filters of the first and second filter elements. And adjusting the focus of the camera according to the coaxial optical interferometer by adjusting the objective lens unit using the focus detection signal output from the focus detection unit. When the block filter is turned off, the passband filter setting of the first and second filter elements and the focus adjustment of the camera are completed, the central controller performs coaxial optical interferometer measurement by controlling the module control unit, the imaging unit, the coaxial illumination unit, and the reference plane generator, respectively. Calculating a second height map and a second low visibility region of the inspection object according to the coaxial optical interferometer measurement by using the reflected image acquired in the coaxial optical interferometer measurement; When the first height map and the first low visibility area calculation and the second height map and the second low visibility area are calculated, the central control unit calculates the complementary height map and calculates the height distribution information of the inspection object by using the same. Three-dimensional shape measurement method using a multi-interferometer, characterized in that the step of determining whether the object is defective. 2. The method of claim 1, wherein the step of turning on the block filter and adjusting the filter setting of the pass bands of the first and third filter elements and the focus of the camera comprises controlling the block filter by controlling the filter controller for the side moiré interferometer measurement. Turning on and setting the first and third filter elements as filters of a pass band, respectively; Setting the magnification of the objective lens by controlling the objective lens controller when the block filter is turned on and the first and third filter elements are replaced with filters having a pass band respectively set; When the magnification of the objective lens is set, the central control unit controls the illumination controller, the filter controller, the objective lens controller, and the focus signal acquisition unit, respectively, to activate the circular lamp, the first lighting device or the second lighting device, and turn on the block filter. And receiving the reflected light reflected from the focus detecting unit to transfer the objective lens unit to adjust the focus of the camera. The method of claim 1, wherein the calculating of the first height map and the first low visibility region of the inspection object using the reflection image acquired by the side moiré interferometer measurement comprises: Checking whether the located second lighting device is selected; When the second lighting device located on one side of the second direction is selected, the central control unit reflects the grid pattern lighting from the grid pattern projecting unit located on one side of the second direction to the inspection object, and then reflects the reflected image and the reference plane generator. Obtain the reflected phase image, calculate the first phase map, define the shadow and saturation area, and acquire the reflected image after irradiating the grid pattern pattern with the audit object in the grid pattern projection unit located on the other side in the second direction. Calculating a second phase map to define shadows and saturated regions; If the shadow and the saturation region are defined from the first phase map and the shadow and the saturation region are defined from the second phase map, the central control unit integrates and integrates the first and second phase maps from the respective shadow and saturation regions. Calculating an average image; When the integrated phase map and the integrated average image are calculated, the central controller is configured to calculate and define a first height map and a first low visibility region using the integrated phase map and the integrated average image. 3D shape measurement method using. 4. The method of claim 3, wherein the defining of the shadow and the saturation region from the first phase map and the defining of the shadow and the saturation region from the second phase map is performed when the second lighting element located on one side of the second direction is selected. The control unit controls the brightness controller according to the set brightness to adjust the brightness of the second lighting device located on one side of the second direction; When the brightness of the second lighting device located on one side of the second direction is adjusted, the central control unit controls the grid controller to transfer the grid devices located on one side of the second direction N times while capturing and storing the reflected image from the camera every transfer. To do that, A central controller extracting and storing the first average image from which the lattice pattern is removed from the N reflected images when the reflected image is stored; Calculating and storing a first phase map by using an N-bucket algorithm when the first average image is extracted; Calculating and defining a shadow and a saturated area in the first phase map when the first phase map is calculated; When the shadow and the saturation region are calculated in the first phase map, the central controller determines whether the second lighting device located on the other side in the second direction of the inspection object is selected and selected by the second lighting device located on the other side in the second direction. And adjusting the brightness of the second lighting device on the other side of the second direction by controlling the lighting controller according to the set brightness. When the brightness of the second lighting device located on the other side of the second direction is adjusted, the central control unit controls the grid controller to transfer the grid devices located on the other side of the second direction N times while storing and storing the reflected image by the camera at every transfer. To do that, A central controller extracting and storing a second average image from which the grid pattern is removed from the N reflected images when the reflected image is stored; Calculating and storing a second phase map by using an N-bucket algorithm when the second average image is extracted; If the second phase map is calculated, the central control unit is configured to calculate and define the shadow and saturation region in the second phase map 3D shape measurement method using a multi-interferometer. The method of claim 1, wherein the step of turning off the block filter and adjusting the filter setting of the pass band of the first and second filter elements and the focus of the camera is performed by the central controller controlling the filter controller to measure the coaxial optical interferometer. Off and setting the first and second filter elements as filters of a pass band, respectively; Setting the magnification of the objective lens by controlling the objective lens controller when the block filter is turned off and the first and second filter elements are replaced by filters having a pass band respectively set; When the magnification of the objective lens is set, the central controller controls the illumination controller, the filter controller, the objective lens controller, and the focus signal acquisition unit, respectively, to activate the circular lamp or the first lighting device, and turn off the block filter to reflect the reflected light reflected from the inspection object. Receiving through the focus detection unit to convey the objective lens unit to adjust the focus of the camera, characterized in that the three-dimensional shape measurement method using a multi-interferometer. The method of claim 1, wherein the calculating of the second height map and the second low visibility area of the inspection object according to the coaxial optical interferometer measurement comprises: setting a scanning range and a transfer step interval of the reference mirror in the central controller; Adjusting the brightness of the first lighting element by controlling a lighting controller according to the set brightness when the scanning range and the transfer step interval of the reference mirror are set; When the first lighting device is adjusted to the set brightness, the central control unit controls the reference mirror controller to transfer the reference mirror N steps, and to take a reflection image from the camera at each step transfer and to obtain and store the captured reflection image; , Calculating, by the central controller, a brightness change for each step in each pixel when the N reflected images are stored; Calculating a height value and a second height map of the inspection object located in the corresponding pixel when the change in brightness of each step is calculated in each pixel; If the height value and the second height map is calculated, the central control unit comprises a step of defining a second low visibility region from the height value and the second height map characterized in that the three-dimensional shape measurement method using a multi-interferometer. The method of claim 1, wherein the calculating of the complementary height map and calculating the height distribution information of the inspection object using the same to determine whether the inspection object is defective or not includes determining the defect level of the first and second low visibility regions. Calculating, by the controller, a third low visibility area that can be complemented by using the first and second low visibility areas; Calculating, by the central controller, a third height map that can be complemented by using a first height map and a second height map when the third low visibility area is calculated; Calculating, by the central controller, height distribution information of the inspection object on the reference plane from the third height map when the third height map is calculated; When the height distribution information is calculated, the central control unit calculates the volume, the representative height and the eccentricity of the inspection object from the height distribution information, and determines whether the inspection object is defective based on the three-dimensional using a multi-interferometer. Shape measuring method.

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