TW202242342A - Hyperspectral reflective interference and non-interferential optical characteristic focus measurement device and method capable of auto-focusing when switching between both interfering and non-interfering devices - Google Patents

Abstract

A hyperspectral reflective interference and non-interferential optical characteristic focus measurement device and method are disclosed. The invention combines the reflective interferometry with the reflective hyperspectral interferometry, which is capable of measuring reflective interference signals and general non-interference signals optical properties. The measurement device of the present invention uses a reflective mirror group to effectively reduce chromatic aberrations caused by different wavelengths and is further applied to interference technologies, so that images of different wavelengths can be located on the same focal plane, which greatly simplifies an optical path structure. Moreover, the measurement process of the present invention can be applied to measurement technologies in different fields and can realize simultaneously measuring and analyzing various signals. The invention can complete measurements of component analysis, color, film thickness, and reconstruction of a two-dimensional and three-dimensional surface morphology of a sample to be measured at the same time. The invention involves using a reflective mirror group, hyperspectral spectrum technologies and characteristics of the short length of white light interference coherence to develop an interferometry architecture and auto-focus technology having interference signal auto-focus and non-interference signal auto-focus functions. Therefore, the present invention can auto-focus when switching between both interfering and non-interfering devices.

Description

Hyperspectral reflective interferometric and non-interferential optical characteristic focus measurement device and method

The invention relates to a pair of optical characteristics of hyperspectral reflective interference and non-interference The focus measurement device and method, especially a reflective hyperspectral interferometry, can solve the problem of chromatic aberration, so that the imaging of different wavelengths is on the same focal plane, which can greatly simplify the optical path structure, and can be applied to measurement technologies in different fields , realize the measurement and analysis of multiple signals at the same time, and use the short coherence length (Coherence) of white light to develop the auto-focus function of interference signals and non-interference signals, so that the device is switched to interference or non-interference measurement. Can autofocus.

According to the current patent search records, most of them use the combination of reflective mirror group and hyperspectral Related technologies (such as ROC Application No. 097116628 and Patent No. 105137195) are used to deal with the problem of different chromatic aberrations (and focal planes) caused by different wavelengths, but no interferometry framework is used. Therefore, from the current patent search content, it is not clear that the technology of interferometry combined with reflective mirrors has not been found. In other words, in reflective interferometry, there is no patent mentioning autofocus technology. The technology is judged by light intensity, and the error is on the order of microns.

Instruments for observing relevant functions on the market, mainly include scanning electron microscope (SEM) for surface contour scanning combined with X-ray energy dispersive X-ray spectrometer (EDX), atomic force microscope (atomic force microscope, AFM), 3D white light interferometer; reflection spectrometer and ellipsometer for film thickness measurement; Wafer inspection. The comparison results of the above machines are shown in Table 1 to Table 3: Table 1 Machine name principle advantage shortcoming SEM with EDX 1. Use electron beam (Electron Beam) to scan the surface of the object to be tested. 2. The electron beam excites the secondary electron signal of the analyte for imaging. 3. Use energy dispersive spectrometer to collect "characteristic X-rays" and analyze the elemental composition of "single point". 1. The surface of the particles is gold-plated, without the limitation of optical diffraction limit, and the image resolution is high quality, which can reach 15-45 Å (provided that there is no charge accumulation). 2. Quickly identify elements that exist. 3. Good depth of field. 1. Metal plating is used for destructive one-time measurement. 2. Due to the fear of polluting the production machine (Chamber) of the fab, it is impossible to enter the Chamber repeatedly for repeated experiments. 3. Often only the signal of gold plating on the surface of the particles is obtained, but the real composition of the particles under the gold plating layer cannot be obtained. 4. The "characteristic X-ray" energy dispersion signal received by EDX, the energy dispersion signal mostly comes from the wafer coating layer with a solid structure, not the particles on the wafer. AFM The atomic force (from between the tip of the probe and the object to be measured) causes the cantilever beam of the probe to be displaced, and the displacement signal is converted into the height of the surface topography. 1. Nanoscale depth analysis to detect wafer surface roughness. 2. 2D/3D material surface topography images. Line scanning takes a lot of time. 3D white light interferometer The interference light comes from the reflected light of both the object to be measured and the reference mirror, and the phase difference of the interference light is used to obtain the surface topography height. 1. Surface roughness can be analyzed due to the low coherence characteristic of white light. 2. With 2D image or PZT movement, reconstruct the height of 3D surface topography, and the reconstruction speed is fast. 1. The higher the resolution, the smaller the depth of field. 2. The 2D grayscale value image required to reconstruct 3D particles requires high quality and is easily affected by noise. Algorithms need to be used, such as filtering method and three-dimensional contour reconstruction algorithm. Table II Machine name principle advantage shortcoming Reflection spectrometer (film thickness measurement) Light covering multiple wavelength ranges is decomposed into spectral lines of different wavelength bands by means of gratings or diffraction gratings. Compared with the ellipsometer 1. The principle is simple and the structure is simple. 2. The price is cheap. 1. The measurement accuracy is worse than that of ellipsometer. 2. Fast measurement speed. Ellipsometer (measuring film thickness) Using polarized light, measure the change of light amplitude and phase after being reflected by the film, and calculate the film thickness, refractive index and extinction coefficient in reverse. Compared with the reflective spectrometer 1. The principle is more complicated, the structure is more complicated, and the measurement accuracy is high. 2. The price is more expensive. 3. Measure thickness information, as well as refractive index and extinction coefficient. 1. The measurement speed is slow. 2. It is very important for the measurement skills and analysis of ellipse parameters. Table three Machine name principle advantage shortcoming Raman Spectroscopy and Fourier Transform Infrared Spectroscopy Spectra that display molecular vibrations are used to characterize organic materials. Complementary relationship with Fourier infrared spectroscopy. 1. Identify particulate organic pollutants. 2. Non-destructive testing. Non-quantitative measurements (requires standards). Near Infrared Cameras for Wafer Inspection Using indium gallium arsenide as a sensor, it responds to light with a wavelength of near-infrared light between 900 and 1700 nm. 1. In industry and scientific research, most of them use near-infrared light. 2. Judging defects, cracks and disconnections of optoelectronic wafers, silicon wafers, and semiconductor lasers. Cracks and hollowing are detected inside the IC circuit (the shorter the wavelength, the deeper the depth). 3. Film thickness measurement. The use of near-infrared light is limited to the properties of the material to be measured.

As can be seen from the comparison results in Table 1 to Table 3 above, the machines currently on the market cannot simultaneously measure It can measure and analyze various signals, such as component analysis, color, wafer film thickness, reconstruct 2D image of particle surface, and reconstruct 3D image of particle surface, etc. Therefore, general users cannot meet the needs of users in actual use.

The main purpose of the present invention is to overcome the above-mentioned problems encountered in the prior art and provide Provides a new technology of reflective hyperspectral interferometry that combines reflective interferometry with hyperspectral. It is capable of measuring the optical characteristics of reflective interference signals and general non-interference signals. Hyperspectral reflective interference and non-interference optical characteristics focus measurement Devices and methods.

Another object of the present invention is to provide a reflective mirror group that can effectively reduce The chromatic aberration problem caused by different wavelengths is further applied to the interference technology, so that the images of different wavelengths are located on the same focal plane, which can greatly simplify the optical path structure of the hyperspectral reflective interference and non-interference optical characteristic focus measurement device.

Another object of the present invention is to provide a measurement technology that can be applied in different fields technology to achieve simultaneous measurement and analysis of multiple signals, including the ability to measure component analysis, color, and film thickness at the same time, reconstruct the two-dimensional surface topography of the sample to be measured (such as the particle on the wafer surface), and reconstruct the three-dimensional surface of the sample to be measured Hyperspectral reflective interferometric and non-interferential focusing measurement methods for optical characteristics of topography (such as wafer surface Particle).

Another object of the present invention is to provide a reflective mirror group and highlight In addition, by taking advantage of the short coherent length of white light interference, we have developed the interference signal auto-focus and non-interference signal auto-focus functions with interferometry architecture and auto-focus technology, so that the device can automatically focus when switching to interference or non-interference measurement. The hyperspectral reflective interferometric and non-interferential optical characteristic focusing measurement device and method.

In order to achieve the above purpose, the present invention is a focusing measurement device for optical characteristics, which is Linnik reflective interference structure, which includes: a measurement light source, which can generate a white light source (White light source) with a short coherence length (Coherence) and other light sources (other source); an electric control switch, which is connected to the measurement light source , used to control the switching state of the white light source and the other light sources, and switch the light source according to the characteristics of the sample to be tested and the needs of the user; several electronically controlled apertures, including the first electronically controlled aperture and the second electronically controlled aperture, are used To filter out noise; several optical elements, including a parallel light mirror group, a beam splitter and an imaging mirror group, when the above device is in operation, the light source generated by the measurement light source is switched from the electric control switch and passes through the The first electronically controlled aperture and the parallel optical mirror group refract and transform the diffused light source into parallel light to the beam splitter, and split the light into a first optical path and a second optical path; two reflective mirror groups are respectively located in the first optical path The first reflective mirror group on one optical path and the second reflective mirror group on the second optical path are used to make multi-wavelength light on the same focal plane; placed between the beam splitter and the second reflective mirror group in the second light path, to control light entering the second reflective mirror group, and make the first reflective mirror group and the second reflective mirror group The light intensity is close, wherein the electric control attenuation film can adjust the light attenuation rate in the range of 0% to 100%; the two electronic control platform components are respectively the first electronic control platform component on the first optical path and the first electronic control platform component on the first optical path. The second electronically controlled platform assembly on the second optical path, wherein each electronically controlled platform assembly is composed of a long-stroke platform and a short-stroke platform placed on the long-stroke platform, and the short stroke of any electronically controlled platform assembly A sample to be tested can be placed on the travel platform; and a photosensitive element. When the above-mentioned device is in operation, the light source hits the reflected light of the sample to be tested through the first optical path and then sends back to the beam splitter to pass through and communicate with the The light reflected back from the second optical path forms an interfering third optical path, and passes through the imaging mirror group and the second electronically controlled aperture along the third optical path to the photosensitive element.

In the focusing measurement device for the above-mentioned optical characteristics of the present invention, the other light sources can be selected from purple External laser light source, visible light laser light source, infrared laser light source or ultra-broadband light source.

In the above-mentioned focusing measurement device for optical characteristics of the present invention, the first electronically controlled aperture and the second The second electronically controlled aperture is to reduce or enlarge the electronically controlled aperture to suppress noise light or increase the light intensity signal.

In the above-mentioned focusing measurement device for optical characteristics of the present invention, each reflective mirror group includes a A combination of a convex mirror and at least one concave mirror or at least one plane mirror.

In the above-mentioned optical characteristic focusing measurement device of the present invention, the short-stroke platform is a micro-distance Piezoelectric (PZT) driven platform, the long stroke platform is an electronically controlled mobile platform.

In the above-mentioned focusing measurement device for optical characteristics of the present invention, the electronically controlled attenuation film is also placed in the Between the beam splitter of the first optical path and the first mirror group.

In the above-mentioned focusing measurement device for optical characteristics of the present invention, the photosensitive element is a hyperspectral light Camera (Hyperspectral imagery, HSI).

The present invention is a focusing measurement method of optical characteristics, which has interference signal and non-interference The signal auto-focus method, with an error of nanometer level, is a method for measuring sample composition analysis, color, film thickness, two-dimensional surface topography, and three-dimensional surface topography by using the above-mentioned optical characteristic focusing measurement device, which at least includes the following Step: Step 1: Use the electric control switch to switch the light source generated by the measurement light source, and use a reference plane mirror on the first optical path as the waiting table placed on the short-stroke platform of the first electric control platform assembly. To measure the sample, set its light attenuation rate to 0% for the electronically controlled attenuation sheet on the second optical path to allow light to pass through, and place a reflective plane mirror on the second electronically controlled platform assembly on the second optical path Use the short-stroke platform as a reference mirror, then adjust the movement of the first electronically controlled platform assembly and the second electronically controlled platform assembly, find interference fringes or find interference fringes to cause the image to change position, this position is the focal plane position, where , when adjusting the movement of the first electronically controlled platform assembly and the second electronically controlled platform assembly, the optical path difference between the reflected light of the reference plane mirror of the first optical path and the reference mirror of the second optical path is the same or an integer multiple, And the frequency is the same, so interference is formed, and finally the third optical path of the interference is synthesized and returned to the imaging lens for focusing along the third optical path, the stray light is filtered through the second electronically controlled aperture, and finally the interference imaging light enters the photosensitive element, Complete hyperspectral reflective interference signal autofocus; Step 2: After finding the interference fringes or finding the position where the interference fringes cause image changes, fix the second electronically controlled platform assembly and the second reflective mirror group; Step 3: Remove The reference plane mirror places the sample to be tested on the short-stroke platform of the first electronically controlled platform assembly, moves the first electronically controlled platform assembly, and finds the interference fringes (that is, the focal plane) or finds the position where the interference fringes cause image changes , obtain the focal plane of the interference signal, and complete the three-dimensional information signal acquisition of hyperspectral interference imaging; and step 4: set the light attenuation rate of the electronically controlled attenuation film on the second optical path to 100% so that light is shielded and cannot enter The second reflective mirror group makes the interference fringes disappear. At this time, the sample to be tested is located at the position of the first electric control platform assembly, which is the focal plane for obtaining non-interference signals. The reflected light of the sample to be tested on the first optical path The imaging lens group and the second electronically controlled aperture pass through the beam splitter and enter the third optical path, and then enter the photosensitive element to complete the three-dimensional information signal acquisition of hyperspectral imaging; wherein when the size of the second electronically controlled aperture is adjusted, it can obtain A 3D information signal with low noise is required.

In the focusing measurement method of the above-mentioned optical characteristics of the present invention, the electronically controlled attenuation sheet shields the light The shield cannot enter under the second reflective mirror group, and when the second electronically controlled aperture is adjusted to shrink, the photosensitive element obtains a one-dimensional image signal of Cube 1 information type, and the Cube 1 is a high-precision signal with less noise. It is suitable for precision measurement of film thickness measurement and defect detection.

In the focusing measurement method of the above-mentioned optical characteristics of the present invention, the electronically controlled attenuation sheet shields the light The shield cannot enter under the second reflective mirror group, when the second electronically controlled aperture is adjusted to enlarge, the photosensitive element is to obtain the two-dimensional image signal of Cube 3 information type, and the Cube 3 is suitable for image recognition, material composition and color judge.

In the focusing measurement method of the above-mentioned optical characteristics of the present invention, the electronic control attenuation film makes the light pass By entering the second reflective mirror group, and making the light intensity of the first reflective mirror group and the second reflective mirror group close to each other, when adjusting the second electronically controlled aperture to enlarge, the photosensitive element obtains Cube 2 information type of two-dimensional image signal, the Cube 2 is a precision interference signal, which is suitable for three-dimensional image reconstruction and stress analysis of the sample to be tested.

In the above-mentioned focusing measurement method of optical characteristics of the present invention, the step 1 to step 3 are dry The operation sequence of the signal-involved auto-focus, the steps 1 to 4 are the operation sequence of the non-interference signal auto-focus.

In the above optical characteristic focus measurement method of the present invention, the electronically controlled switch is related to the measurement The light source is switched to a white light source. Taking advantage of the short coherence length, the interference fringes are suitable for signal measurement of the focal plane and Cube 1, Cube 2, and Cube 3 information types.

Please refer to "Figure 1", which is the structure of the optical characteristic focusing measurement device of the present invention schematic diagram. As shown in the figure: the present invention is a hyperspectral reflective interference and non-interference optical characteristic focus measurement device and method, which is characterized by including an optical characteristic focus measurement device, and using the optical characteristic focus measurement device to measure samples Methods for component analysis, color, film thickness, two-dimensional surface topography, and three-dimensional surface topography. The proposed focusing measuring device 100 for optical characteristics is a Linnik reflective interferometry architecture, which mainly uses Linnik reflective interferometry, and can complement Mirau interferometry to achieve complementary effects. The device 100 includes a measuring light source 10, an electronically controlled switch 20, several electronically controlled apertures 30 and 31, several optical elements 40, 41 and 42, two reflective mirror groups 50 and 51, an electronically controlled attenuation A sheet (or light baffle) 60, two electric control platform components 70 and 71, and a photosensitive element 80 are formed.

The measurement light source 10 mentioned above can produce a short coherence White light source (White light source) and other light source (other source). The other light source is selected according to the characteristics of the sample to be tested or the needs of the user, such as ultraviolet laser light source, visible light laser light source, infrared laser light source or ultra-broadband light source.

The electric control switch 20 is connected to the measurement light source 10 to control the white light source and The switching state of the other light sources is to switch the light sources according to the characteristics of the sample to be tested and the needs of users.

Several electronically controlled apertures 30 and 31 are composed of a first electrically controlled aperture 30 and a second electrically controlled aperture. Aperture 31 is the function of suppressing noise light or increasing light intensity signal by reducing or enlarging the aperture electronically. However, it should be noted that although two electronically controlled apertures 30 and 31 are used in this embodiment, the design can be changed according to requirements during actual operation, and any number of electronically controlled apertures can be used and placed at any position in the device of the present invention. It is not limited to the structure of this embodiment.

The plurality of optical elements 40, 41 and 42 comprise a parallel optical lens group 40, A beam splitter 41 and an imaging mirror group 42. When the above-mentioned device is in operation, the light source generated by the measurement light source 10 is switched from the electric control switch 20 and passes through the first electric control aperture 30 and the parallel optical mirror group 40. The diffused and propagated light source is refracted and transformed into parallel light, which is sent to the beam splitter 41, and the light is split into the first light path. 90 and the second light path 91.

The two reflective mirror groups 50 and 51 are respectively the first and second mirrors located on the first optical path 90. A reflective mirror group 50 and a second reflective mirror group 51 located on the second optical path 91 are used to make the multi-wavelength light on the same focal plane. Each of the reflective mirror groups 50 and 51 consists of a convex mirror 501, 511, a combination of at least one concave mirror 502, 512 or at least one flat mirror. However, it should be noted that although the combination of two concave mirrors 502 and 512 obliquely placed above the convex mirrors 501 and 511 is used in this embodiment, the design of different combinations of convex and concave mirrors can be changed according to different imaging effect requirements during actual operation. The number of convex-concave mirrors can be arranged at any position in the device of the present invention, not limited to the structure of this embodiment.

The electronically controlled attenuation film 60 is placed between the optical splitter 41 and the second optical path 91. Between the second reflective mirror group 51, it is used to control the light entering the second reflective mirror group 51, and make the light intensity of the first reflective mirror group 50 and the second reflective mirror group 51 close, and the electric control The light attenuation film 60 can adjust the light attenuation rate in the range of 0% to 100%. However, it should be noted that although the electronically controlled light attenuation sheet 60 is placed on the second optical path 91 in this embodiment, the design can be changed according to requirements during actual operation, for example, the electronically controlled light attenuation sheet is placed The position between the beam splitter and the first mirror group to the first optical path in the device of the present invention is not limited to the structure of this embodiment.

The two electric control platform components 70 and 71 are respectively located on the first optical path 90 The first electric control platform assembly 70 and the second electric control platform assembly 71 located on the second optical path 91, wherein each electric control platform assembly 70 and 71 is composed of a long stroke platform 701, 711 and a The short-stroke platforms 702 and 712 on the platforms 701 and 711 are composed, and a sample 1 to be tested can be placed on the short-stroke platforms 702 and 712 of any electric control platform assembly 70 and 71 . In this embodiment, the short-stroke platforms 702 and 712 are micro-distance piezoelectric (PZT) driven platforms, and the long-stroke platforms 701 and 711 are electronically controlled mobile platforms.

The photosensitive element 80 is a hyperspectral camera (Hyperspectral imagery, HSI), It is a receiver. When the above-mentioned device is in operation, the reflected light from the light source that hits the sample 1 to be tested 1 via the first optical path 90 is sent back to the beam splitter 41 to pass through and formed with the light reflected back from the second optical path 91. The interfering third optical path 92 , and passes through the imaging lens group 42 and the second electronically controlled aperture 31 to the photosensitive element 80 along the third optical path 92 .

Please refer to "Fig. 2A～Fig. 2D" for further reference. Schematic diagram of the first autofocus process of the optical characteristic focus measurement device, the second schematic diagram of the autofocus process of the optical characteristic focus measurement device of the present invention, the third schematic diagram of the autofocus process of the optical characteristic focus measurement device of the present invention, and the optical characteristic focus amount of the present invention Four schematic diagrams of the autofocus process of the test device. As shown in the figure: when the above-mentioned optical characteristic focusing measuring device 100 is used to perform automatic focusing, Figures 2A to 2C The picture shows the operation sequence of the interference signal autofocus, and the 2A~2D pictures are the non-interference signal autofocus order of operation.

As shown in Figure 2A, use the electric control switch 20 to switch the measurement light source 10 to White light source (or choose other light sources, such as ultraviolet light or halogen light, etc.), taking advantage of the short coherence length, its interference fringes are suitable for finding the signal measurement of the focal plane and subsequent Cube 1, Cube 2 and Cube 3 information types. In the first reflective mirror group 50 , a reference plane mirror 1 a is selected for the sample to be tested, and it is placed on the short-stroke platform 702 of the first electronically controlled platform assembly 70 . In the second reflective mirror group 51, adjust the light intensity of the electronically controlled attenuation sheet 60, set its light attenuation rate to 0% to allow light to pass through, and select a reflective flat mirror, place it on the second electric The short stroke platform 712 of the control platform assembly 71 is used as the reference mirror 1b. Then adjust the movement of the first electric control platform assembly 70 and the second electric control platform assembly 71 to find the interference fringe or find the interference fringe to cause the image to change position, and this position is the focal plane position. Wherein, when adjusting the movement of the first electronic control platform assembly 70 and the second electronic control platform assembly 71, the optical paths of the light reflected by the reference plane mirror 1a of the first optical path 90 and the reference mirror 1b of the second optical path 91 The difference is the same or an integer multiple, and the frequency is the same, so interference is formed, and finally the synthesized interference light returns to the imaging lens 42 to focus along the third optical path 92, and the stray light is filtered out by the second electronically controlled aperture 31, and finally the interference imaging Light enters the photosensitive element 80 (hyperspectral camera) to complete hyperspectral reflective interference signal autofocus.

As shown in Fig. 2B, when the interference fringe is found or the image is changed due to the interference fringe After the position is fixed, the second electric control platform assembly 71 and the second reflective mirror group 51 are fixed.

As shown in Figure 2C, the reference plane mirror 1a is removed, and the sample to be tested 1 is placed On the short-stroke platform 702 of the first electronically controlled platform assembly 70, move the first electronically controlled platform assembly 70 to find the interference fringe (that is, the focal plane) or find the position where the image is changed by the interference fringe, and obtain the focal plane of the interference signal , to complete the three-dimensional information signal acquisition of hyperspectral interference imaging.

As shown in Figure 2D, the electronically controlled attenuation film 60 on the second optical path 91 is set to Its light attenuation rate is 100%, so that the light is shielded and cannot enter the second reflective mirror group 51, so that the interference fringes disappear. lose. At this time, the sample 1 to be tested is located at the position of the first electric control platform assembly 70, that is, the focal plane for obtaining non-interference signals; the light reflected from the sample 1 to be tested on the first optical path 90 passes through the beam splitter 41 and enters the first optical path 90. After the imaging lens group 42 and the second electronically controlled aperture 31 of the three optical paths 92 enter the photosensitive element 80 (hyperspectral camera) to complete the three-dimensional information signal acquisition of hyperspectral imaging; when adjusting the size of the second electronically controlled aperture 31 , can obtain the required three-dimensional information signal with low noise for high-precision measurement of film thickness, defect, color, composition and image recognition.

Please refer to "Fig. 3A～Fig. 3C" for further reference, which are respectively the light of the present invention. Schematic diagram of the measurement process 1 of the optical characteristic focusing measurement device, the measurement flow 2 schematic diagram of the optical characteristic focusing measurement device of the present invention, and the measurement flow 3 schematic diagram of the optical characteristic focusing measurement device of the present invention. As shown in the figure: when using the above-mentioned optical characteristic focusing measuring device 100 to perform measurement, the sequence of the operation mode of the present invention is taken from Figure 3A to Figure 3C, so as to obtain the differences between Cube 1, Cube 3 and Cube 2, etc. An image signal of information type.

As shown in Figure 3A, use the electric control switch 20 to switch the measurement light source 10 to white light source, and make the electronically controlled light attenuation sheet 60 block the light from entering the second reflective mirror group 51, and adjust and shrink the second electronically controlled aperture 31. Finally, the photosensitive element 80 (hyperspectral camera) is made to obtain the one-dimensional image signal of Cube 1 information type. The Cube 1 is a high-precision signal with less noise, and is often used for precision measurement, such as film thickness measurement and defect detection.

As shown in Figure 3B, the second electronically controlled aperture 31 is adjusted and enlarged, and the rest of the structure is dimensionally Keeping Fig. 3A unchanged, the photosensitive element 80 (hyperspectral camera) obtains the two-dimensional image signal of Cube 3 information type. The signal noise of Cube 3 will be more than that of Cube 1, which is suitable for image recognition, material composition and color discrimination, etc.

As shown in Figure 3C, adjust the electronically controlled light attenuation sheet 60 so that the light can enter the second reflective mirror group 51, and make the light intensity of the first reflective mirror group 50 and the second reflective mirror group 51 Closely, the rest of the structure remains unchanged in Figure 3B, and the photosensitive element 80 (hyperspectral camera) obtains the two-dimensional image signal of Cube 2 information type. The Cube 2 is a precision interference signal, which is mainly applicable to the three-dimensional image reconstruction and stress analysis of the sample 1 to be tested. For example, the surface profile scan in Table 1 above is classified in Cube 2.

Table 4 below shows the comparison results of the present invention and related functional instruments on the market according to the above Tables 1 to 3. It can be seen from Table 4 that the present invention can complete the measurement of component analysis, color, film thickness, reconstruction of the two-dimensional surface topography of the sample to be measured (such as the Particle on the surface of the wafer), and the reconstruction of the three-dimensional surface topography of the sample to be tested (such as Particle on the wafer surface), etc. This is a technical effect that cannot be achieved by machines currently on the market. Moreover, the current auto-focus technology on the market uses light intensity judgment, and the error is on the order of microns; however, the present invention is equipped with interference signal and non-interference signal auto-focus technology, and utilizes the characteristic of short interferometric coherence length of white light, and the error is on the order of nanometers. Table four Machine name Composition Analysis color Wafer film thickness Reconstruct the 2D image of the Particle surface Reconstruct the 3D image of the Particle surface This device ˇ ˇ ˇ ˇ ˇ SEM with EDX ˇ x x ˇ x AFM x x x ˇ ˇ 3D white light interferometer x ˇ x ˇ ˇ Reflection spectrometer (film thickness measurement) x x ˇ x x Ellipsometer (measuring film thickness) x x ˇ x x Raman Spectroscopy and Fourier Transform Infrared Spectroscopy ˇ x x x x Near Infrared Cameras for Wafer Inspection x x ˇ x x

In this way, the present invention proposes a pair of optical characteristics of hyperspectral reflective interference and non-interference The focus measurement device and method is a new technology of reflective hyperspectral interferometry that combines interferometry with reflective mirror groups. It has the optical characteristics of measuring reflective interference signals and general non-interference signals. The measurement device of the present invention uses reflective mirrors to effectively reduce the chromatic aberration caused by different wavelengths, and is further applied to interference technology, so that images of different wavelengths are located on the same focal plane, which greatly simplifies the optical path structure. Moreover, the measurement process of the present invention can be applied to measurement technologies in different fields, and can realize simultaneous measurement and analysis of multiple signals. Its technical scope includes two technical fields of image recognition and precision measurement. For example, the present invention can simultaneously Complete the measurement of component analysis, color, film thickness, reconstruction of the two-dimensional surface topography of the sample to be tested (such as the Particle on the wafer surface), and the reconstruction of the three-dimensional surface topography of the sample to be tested (such as the Particle on the wafer surface), etc., currently on the market There is no similar machine, which has great market potential. In addition to having a reflective mirror group and a hyperspectral spectrum, the present invention also utilizes the short length of white light interference coherence to develop interference signal auto-focus and non-interference signal auto-focus functions with interferometry architecture and auto-focus technology, making the present invention switch to Autofocus is available for both interfering and non-interfering devices. When the hyperspectral technology becomes more and more mature in the future, it has the potential to become the mainstream of the market instrument architecture with the reflective mirror group instrument of the present invention, especially the related applications of hyperspectral interferometry and high-precision autofocus instruments.

In summary, the present invention is a hyperspectral reflective interference and non-interference optical characteristics The focus measurement device and method can effectively improve various shortcomings of conventional methods. It combines reflective interferometry with hyperspectral reflective hyperspectral interferometry, which can solve the problem of chromatic aberration, and make the imaging of different wavelengths on the same focal plane, which can greatly simplify The optical path structure is applied to measurement technologies in different fields, and realizes the measurement and analysis of multiple signals at the same time, and uses the short length of white light interference coherence to develop the autofocus function of interference signals and non-interference signals, so that the device can be switched to Auto-focusing is possible during interference or non-interference measurement, which makes the invention more advanced, more practical, and more in line with the needs of users.

However, what is described above is only a preferred embodiment of the present invention, and should not be limited thereto. The scope of the implementation of the present invention; therefore, all brief descriptions made according to the scope of patent application for the present invention and the content of the description of the invention Any single equivalent change and modification shall still fall within the scope covered by the patent of the present invention.

100:Optical characteristic focus measurement device 1: Sample to be tested 1a: Reference plane mirror 1b: Reference mirror 10: Measuring light source 20: Electric control switch 30: The first electronically controlled aperture 31: Second electronically controlled aperture 40: parallel light mirror group 41: Optical splitter 42: Imaging mirror group 50: The first reflective mirror group 501: Convex mirror 502: concave mirror 51: Second reflective mirror group 511: Convex mirror 512: concave mirror 60: Electronically controlled attenuation film (or light baffle) 70: Electronic control platform components 701: Long stroke platform 702: short stroke platform 71: Electronic control platform components 711: Long stroke platform 712: short stroke platform 80: photosensitive element 90: The first light path 91: Second light path 92: The third light path

Figure 1 is a schematic diagram of the structure of the focusing measurement device for optical characteristics of the present invention. Fig. 2A is a schematic diagram of the automatic focusing process of the optical characteristic focusing measurement device of the present invention. Fig. 2B is a schematic diagram of the second auto-focusing process of the optical characteristic focusing measurement device of the present invention. Fig. 2C is a schematic diagram of the third automatic focusing process of the optical characteristic focusing measurement device of the present invention. Figure 2D is a schematic diagram of the fourth autofocus process of the optical characteristic focus measurement device of the present invention. Fig. 3A is a schematic diagram of a measurement process of the focusing measurement device for optical characteristics of the present invention. Fig. 3B is a schematic diagram of the second measurement process of the optical characteristic focus measurement device of the present invention. Figure 3C is a schematic diagram of the third measurement process of the focusing measurement device for optical characteristics of the present invention.

100:Optical characteristic focus measurement device

1: Sample to be tested

10: Measuring light source

20: Electric control switch

30: The first electronically controlled aperture

31: Second electronically controlled aperture

40: parallel light mirror group

41: Optical splitter

42: Imaging mirror group

50: The first reflective mirror group

501: Convex mirror

502: concave mirror

51: Second reflective mirror group

511: Convex mirror

512: concave mirror

60: Electronically controlled attenuation film (or light baffle)

70: Electronic control platform components

701: Long stroke platform

702: short stroke platform

71: Electronic control platform components

711: Long stroke platform

712: short stroke platform

80: photosensitive element

90: The first light path

91: Second light path

92: The third optical path

Claims (13)

A focus measurement device for optical characteristics is a Linnik reflective interference structure, which includes: A measuring light source, which can produce white light source and other light source with short coherence length (Coherence); An electric control switch, which is connected to the measurement light source, is used to control the switch state of the white light source and the other light source, and switches the light source according to the characteristics of the sample to be tested and the user's needs; Several electrically controlled apertures, including a first electrically controlled aperture and a second electrically controlled aperture, are used to filter out noise; Several optical elements, including a parallel light mirror group, a beam splitter and an imaging mirror group, when the above device is in operation, the light source generated by the measurement light source is switched from the electric control switch and passes through the first electric control aperture and the The parallel light mirror group refracts and transforms the diffused light source into parallel light and sends it to the beam splitter, where the light is split into a first light path and a second light path; Two reflective mirror groups, respectively a first reflective mirror group located on the first optical path and a second reflective mirror group located on the second optical path, are used to make multi-wavelength light on the same focal plane; An electronically controlled light attenuation sheet (or light baffle) is placed between the beam splitter of the second light path and the second reflective mirror group to control light entering the second reflective mirror group and make the The light intensity of the first reflective mirror group is close to that of the second reflective mirror group, wherein the electronically controlled light attenuation sheet can adjust the light attenuation rate in the range of 0% to 100%; Two electronically controlled platform components are respectively a first electronically controlled platform component located on the first optical path and a second electrically controlled platform component located on the second optical path, wherein each electrically controlled platform component consists of a long stroke platform and A short-stroke platform placed on the long-stroke platform, and a sample to be tested can be placed on the short-stroke platform of any electric control platform component; and A photosensitive element, when the above device is in operation, the light source hits the sample to be tested via the first optical path The reflected light is sent back to the third optical path that interferes with the light reflected back from the second optical path after passing through the beam splitter, and passes through the imaging mirror group and the second electronically controlled aperture along the third optical path to the photosensitive element. According to the focus measurement device for optical characteristics described in Item 1 of the scope of the patent application, the other light source can be selected from ultraviolet laser light source, visible light laser light source, infrared laser light source or ultra-broadband light source. The focus measuring device for optical characteristics according to item 1 of the scope of the patent application, wherein the first electronically controlled aperture and the second electronically controlled aperture are reduced or enlarged by electronically controlled apertures to suppress noise light or increase light intensity signal function. According to the optical characteristic focus measurement device described in item 1 of the scope of the patent application, each reflective mirror group includes a combination of a convex mirror and at least one concave mirror or at least one plane mirror. According to the optical characteristic focus measurement device described in item 1 of the scope of the patent application, the short-stroke platform is a micro-distance piezoelectric (PZT) drive platform, and the long-stroke platform is an electronically controlled mobile platform. According to the optical characteristic focus measurement device described in item 1 of the scope of the patent application, the electronically controlled attenuation film can be further placed between the beam splitter and the first mirror group in the first optical path. According to the optical characteristic focusing measurement device described in item 1 of the scope of the patent application, the photosensitive element is a hyperspectral camera (Hyperspectral imagery, HSI). A focus measurement method for optical characteristics, equipped with interference signal and non-interference signal auto-focus methods, with an error of nanometer level, is measured by using the optical characteristic focus measurement device described in any one of items 1 to 6 of the scope of the patent application A method for measuring sample composition analysis, color, film thickness, two-dimensional surface topography, and three-dimensional surface topography, which at least includes the following steps: Step 1: Use the electronic control switch to switch the light source generated by the measurement light source, and use a reference plane mirror on the first optical path as the sample to be tested placed on the short-stroke platform of the first electronic control platform assembly , setting its light attenuation rate to 0% for the electronically controlled attenuation film on the second optical path to allow the light to pass through, and placing a reflective flat mirror on the short stroke of the second electronically controlled platform assembly on the second optical path The platform is used as a reference mirror, and then the movement of the first electronically controlled platform component and the second electronically controlled platform component is adjusted to find interference fringes or find interference fringes to cause the image to change position. This position is the position of the focal plane. When the first electric control platform assembly and the second electric control platform assembly move, the optical path difference between the reflected light of the reference plane mirror of the first optical path and the reference mirror of the second optical path is the same or an integer multiple, and the frequency The same, so interference is formed, and finally the third optical path of the interference is synthesized and returned to the imaging lens for focusing along the third optical path, and the stray light is filtered through the second electronically controlled aperture, and finally the interference imaging light enters the photosensitive element to complete a high Spectral reflective interference signal autofocus; Step 2: After finding the interference fringes or finding the position where the interference fringes cause the image to change, fix the second electric control platform assembly and the second reflective mirror group; Step 3: Remove the reference plane mirror, place the sample to be tested on the short-stroke platform of the first electronically controlled stage assembly, move the first electronically controlled stage assembly, find interference fringes (that is, the focal plane) or find interference fringes The position that causes the image to change, the focus plane of the interference signal is obtained, and the three-dimensional information signal acquisition of the hyperspectral interference imaging is completed; and Step 4: Set the light attenuation rate of the electronically controlled attenuation film on the second optical path to 100% so that the light is shielded and cannot enter the second reflective mirror group so that the interference fringes disappear. At this time, the sample to be tested is located at The position of the first electronically controlled platform component is the focal plane for obtaining non-interference signals, the reflected light of the sample to be tested on the first optical path passes through the beam splitter and enters the imaging lens group and the second electrical path of the third optical path After the aperture is controlled, it enters the photosensitive element to complete the three-dimensional information signal acquisition of hyperspectral imaging; when the size of the second electronically controlled aperture is adjusted, the required three-dimensional information signal with low noise can be obtained. According to the optical characteristic focus measurement device described in item 8 of the scope of the patent application, when the electronically controlled attenuation film blocks the light from entering the second reflective mirror group, when the second electronically controlled aperture is adjusted to shrink, The photosensitive element obtains the one-dimensional image signal of Cube 1 information type. The Cube 1 is a high-precision signal with less noise, which is suitable for precise measurement of film thickness measurement and defect detection. According to the optical characteristic focusing measurement device described in item 8 of the scope of the patent application, when the electronically controlled attenuation film blocks the light from entering the second reflective mirror group, when the second electronically controlled aperture is adjusted to enlarge, The photosensitive element obtains the two-dimensional image signal of Cube 3 information type, and the Cube 3 is suitable for image identification, material composition and color identification. The focus measuring device for optical characteristics according to item 8 of the scope of the patent application, wherein the electronically controlled attenuation sheet allows light to pass into the second reflective mirror group, and makes the first reflective mirror group and the first reflective mirror group When the light intensity of the two reflective mirror groups is close to each other, when the second electronically controlled aperture is adjusted to enlarge, the photosensitive element obtains the two-dimensional image signal of Cube 2 information type, and the Cube 2 is a precision interference signal, which is suitable for the sample to be tested 3D image reconstruction and stress analysis. According to the optical characteristic focusing measurement device described in item 8 of the scope of the patent application, the steps 1 to 3 are the operation sequence of the interference signal auto-focus, and the steps 1 to 4 are the operation sequence of the non-interference signal auto-focus. According to the optical characteristic focusing measurement device described in item 8 of the scope of the patent application, the electronically controlled switch switches the measurement light source into a white light source, and the interference fringes are suitable for finding the focal plane and Signal measurement of Cube 1, Cube 2 and Cube 3 information types.

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