CN108426530A - The device and measurement method that a kind of film thickness measures simultaneously with refractive index - Google Patents

Abstract

The device and measurement method measured simultaneously the invention discloses a kind of film thickness and refractive index, belongs to field of optical measurements.Specifically include wide spectrum light source output module, narrow-linewidth laser light source output module, film thickness measuring probe module, demodulated interferential instrument module and acquisition and five part of control module.The output signal of narrow-linewidth laser light source output module is directly inputted in demodulated interferential instrument module by the present invention, meets while interference signal is total to light path and avoids the influence of laser transmitted light and laser multiple reflections light to interference signal quality in film thickness measuring probe module；Length by controlling film thickness measuring probe tail optical fiber avoids the interference that wide spectrum optical transmitted light identifies characteristic signal peak in film thickness measuring probe module.Present invention realization, which is not required to calibration sample calibration, to carry out non-cpntact measurement to the thickness and refractive index of film, have many advantages, such as that self calibration, measurement result can trace to the source, stability is high, characteristic signal identification is simple.

Description

Device and method for simultaneous measurement of film thickness and refractive index

technical field

The design of the invention belongs to the field of optical measurement, and in particular relates to a device and a measurement method for simultaneously measuring film thickness and refractive index.

Background technique

With the vigorous development of material science and technology, in order to meet the urgent needs of microelectronics, optoelectronics, new energy and other fields, thin films are widely used in optical engineering, mechanical engineering, communication engineering, biological engineering, aerospace engineering, chemical engineering, medical engineering and other fields. is widely used. The thickness of the film is not only one of the key parameters in film production, but also determines the application performance of the film in mechanical, electromagnetic, optoelectronic and optical scenarios. Accurate measurement of film thickness has always been one of the most important links in film production and application.

In 1941, N. Schwartz and others proposed a contact probe method that uses high-precision mechanical stylus to move on the surface of an object to sense changes in surface contours (N. Schwartz, R. Brown, "A Stylus Method for Evaluating the Thickness of Thin Films and Substrate Surface Roughness,” in Transactions of the Eighth Vacuum Symposium and Second International Congress (Pergamon, New York, 1941), pp.834–845.), this method has the advantages of good stability, high resolution, and large measurement range ; However, since the probe method includes a probe based on mechanical motion, secondary processing is required when measuring the thin film. In addition, the movement of the probe on the surface of the thin film will also cause certain damage to the thin film. Therefore, the non-contact measurement method quickly replaced the contact measurement method to measure the thickness of the film.

In 2013, Ma Xizhi and others from Nanjing University of Aeronautics and Astronautics disclosed an ultrasonic film thickness measuring instrument and its measurement method (Chinese patent application number: 201310198294.9). The thickness of the oil film is measured by measuring the correlation characteristics of the reflected pulse; however, this method is only suitable for the measurement of the liquid model, and different models need to be established for films with different thickness ranges, and the demodulation is difficult.

The optical measurement method has the advantage of high precision, and it has gradually been widely used in the measurement of film thickness. In 2012, Qu Lianjie and others from Beijing BOE Optoelectronics Technology Co., Ltd. disclosed a film thickness device and method (Chinese patent application number: 201210080754.2). Spectroscopic treatment is performed to irradiate the surface of the film, and the thickness of the film is measured by measuring the characteristics of different reflected light. The method expands the spectrum range of the sampling point of the device for measuring the film thickness and improves the resolution.

As a part of the optical measurement method, white light interferometry has gradually begun to develop in the field of film thickness measurement due to its absolute measurement advantages. The basic principle of white light interferometry is: a scanning mirror is connected to the end of one arm of the white light interferometer as the sensing arm, the length of the other arm is fixed as the reference arm, and the length of the sensing arm is changed by moving the scanning mirror. When the optical path of the transmitted light matches the optical path of the transmitted light in the reference arm, the maximum interference peak appears, and the measurement of related parameters is realized by identifying the position of the peak. In 2008, Peter J.de Groot et al. of Zygo Company of the United States disclosed a scanning interferometry for thin film thickness and surface measurements (Scanning interferometry for thin film thickness and surface measurements, US Patent 7448799), which uses the principle of white light interference The film thickness measurement method uses the Fourier transform method to extract two peaks from the interference light intensity map. This method is not affected by the film thickness. The light source coherence length of the thin film. In 2014, Jia Chuanwu of Shandong University and others disclosed a system for measuring film thickness by wide-spectrum optical interferometry (Chinese patent application number: 201410290494.1). Interferometer, the thickness of the film to be tested can be obtained by measuring the length of the Fabry Perot cavity before and after placing the film to be tested under the mirror. This method has a simple structure and high measurement accuracy. Under the mirror, it is easy to damage the morphology of the film surface.

In 2017, the research group of the applicant of the present invention proposed a common optical path self-calibration film thickness measurement device and measurement method (Chinese patent application number CN201710277954.0), which is realized by using a common optical path wide-spectrum optical interferometer and laser interferometer The measurement of film thickness has the advantages of common optical path and no need to calibrate the device, but this method cannot eliminate the influence of laser transmitted light, resulting in cracking of laser interference signals and affecting the accuracy of thickness measurement; in the same year, the research group of the applicant of the present invention proposed Polarization multiplexing common optical path self-calibration film thickness measurement device and measurement method (Chinese patent application number CN201710277939.6), this method can further eliminate the influence of transmitted light on the measurement results on the basis of the original advantages, but the device construction is relatively complicated .

The invention provides a device and a measuring method for simultaneously measuring film thickness and refractive index, which can simultaneously realize non-contact measurement of film thickness and refractive index. The design of the differential structure in the film thickness measurement probe module reduces the influence of the external environment on the film thickness measurement probe. The present invention directly inputs the output signal of the narrow linewidth laser output module into the demodulation interferometer module to meet the common optical path of the interference signal. At the same time, it avoids the influence of laser transmitted light and laser multiple reflection light in the film thickness measurement probe module on the quality of the interference signal, and improves the accuracy of film thickness traceability; by controlling the length of the film thickness measurement probe pigtail, the film thickness measurement probe is avoided. The interference of the wide-spectrum light transmitted light in the module on the characteristic signal peak improves the accuracy of characteristic signal identification. The invention can be widely used in thin film production and other fields where the thickness of the thin film needs to be measured with high precision.

Contents of the invention

The purpose of the present invention is to provide a film thickness and refractive index that can be measured without calibration of samples, and has self-calibration, traceable measurement results, high stability, strong anti-interference ability, and simple identification of characteristic signals. Device and method for simultaneous measurement of refractive index.

The purpose of the present invention is achieved through the following technical solutions:

A device for simultaneous measurement of film thickness and refractive index, consisting of five parts: a wide-spectrum light output module 1, a narrow linewidth laser output module 2, a film thickness measurement probe module 3, a demodulation interferometer module 4, and an acquisition and control module 5 ; The components of each module are:

The broadband light output module 1 is composed of a broadband light source 101 and a first isolator 102 .

The narrow linewidth laser output module 2 is composed of a narrow linewidth laser light source 201 and a second isolator 202 .

The film thickness measuring probe module 3 is composed of a first measuring probe 301 and a second measuring probe 302 .

The demodulation interferometer module 4 is composed of the first Faraday reflector 401, the second Faraday reflector 402, the first collimator 403, the second collimator 404, the 3rd collimator 405, and the 3rd collimator 404. 4 collimator mirror 406, the first demodulation interferometer coupler 407, the optical path scanning device 408, the second demodulation interferometer coupler 409, the fifth collimator mirror 410, the sixth collimator mirror 411, the seventh collimator mirror 412, the eighth collimating mirror 413, the third Faraday mirror 414 and the fourth Faraday mirror 415.

The acquisition and control module 5 is composed of a computer 501 , a data acquisition card 502 , a first photodetector 503 , a second photodetector 504 , a third photodetector 505 and a fourth photodetector 506 .

The output light of the wide-spectrum light output module 1 is divided into two paths through the first beam splitter coupler 6 and enters the first measuring probe 301 and the second measuring probe 301 of the film thickness measuring probe module 3 through the first circulator 10 and the second circulator 13 respectively. Carry out the measurement of relevant parameter in the measurement probe 302; The return light of the 1st measurement probe 301 and the 2nd measurement probe 302 enters the 1st wavelength division multiplexer 8 and the 2nd wavelength through the 1st circulator 10, the 2nd circulator 13 The relevant wavelength input end of the division multiplexer 9; the output light of the narrow linewidth laser output module 2 is divided into two paths through the second beam splitter coupler 7 and enters the first wavelength division multiplexer 8 and the second wavelength division multiplexer respectively. The relevant wavelength input end of the multiplier 9; the two beams of light combined by the first wavelength division multiplexer 8 and the second wavelength division multiplexer 9 are respectively input into the demodulation interferometer module 4, and passed through the demodulation interferometer The scanning of the first demodulation interferometer 4A and the second demodulation interferometer 4B in the module 4 realizes optical path matching respectively; After the signal is separated, it is input into the acquisition and control module 5 .

The half-spectrum width of the wide-spectrum light source 101 in the wide-spectrum light output module 1 is greater than 45nm, and the output power is greater than 2mW; the half-spectrum width of the narrow-linewidth laser source 201 in the narrow-linewidth laser output module 2 is less than 1pm, and the output power is Greater than 2mW; the wide-spectrum light source 101 and the narrow-linewidth laser light source 201 have different central wavelengths, and the spectra of the two do not overlap within the half-spectrum width;

The first measuring probe 301 and the second measuring probe 302 in the film thickness measuring probe module 3 can realize the transmission and reflection of the transmitted light at the same time, and the reflectivity of the transmitted light is between 20% and 80%; the first measuring probe 301 and the The outgoing rays of the second measuring probe 302 coincide with each other; when the device under test is placed for measurement, they are perpendicular to the outgoing rays of the first measuring probe 301 and the second measuring probe 302 respectively; the output end 10c of the first measuring probe 301 and the first circulator 10 connected, the second measuring probe 302 is connected to the output end 13c of the second circulator 13;

The length difference between the first measuring probe 301 and the second measuring probe 302 in the film thickness measuring probe module 3 is greater than the optical path scanning range of the optical path scanning device 408 in the demodulation interferometer module 4;

The output end 5c of the first wavelength division multiplexer 5 in the demodulation interferometer module 4 is connected with the 4a input end of the first demodulation interferometer coupler 407, and the 4c output end of the first demodulation interferometer coupler 407 Connect with the first collimator mirror 403, the second collimator mirror 404 is connected with the first Faraday reflector 401, the 4d output end of the first demodulation interferometer coupler 407 is connected with the 5th collimator mirror 410, the first 6. The collimating mirror 411 is connected with the 3rd Faraday reflector 414; the 9c output terminal of the 2nd wavelength division multiplexer 9 is connected with the 4g input terminal of the 2nd demodulation interferometer coupler 409, and the 2nd demodulation interferometer The 4e output end of the coupler 409 is connected with the 4th collimator mirror 406, the 3rd collimator mirror 405 is connected with the 2nd Faraday reflector 402, the 4f output end of the 2nd demodulation interferometer coupler 409 collimates the 8th Mirror 413 is connected, and the 7th collimating mirror 412 is connected with the 4th Faraday reflector 415; The first demodulation interferometer coupler 407, the first collimating mirror 403, the second collimating mirror 404, the first Faraday reflector 401, the first forward movable optical mirror 408a, the first reverse movable optical mirror 408b, the fifth collimator mirror 410, the sixth collimator mirror 411, and the third Faraday mirror 414 constitute the first demodulation interference Instrument 4A; the second demodulation interferometer coupler 409, the third collimating mirror 405, the fourth collimating mirror 406, the second Faraday mirror 402, the second forward movable optical mirror 408c, the second reverse movable The moving optical mirror 408d, the 7th collimating mirror 412, the 8th collimating mirror 413, and the 4th Faraday mirror 415 constitute the second demodulation interferometer 4B; the 1st collimating mirror 403, the 2nd collimating mirror 404, the The optical parameters of the 3 collimating mirror 405, the 4th collimating mirror 406, the 5th collimating mirror 410, the 6th collimating mirror 411, the 7th collimating mirror 412, and the 8th collimating mirror 413 are consistent; the first Faraday reflection The optical parameters of mirror 401, the 2nd Faraday reflector 402, the 3rd Faraday reflector 414, and the 4th Faraday reflector 415 are consistent;

The first forward movable optical reflector 408a, the second forward movable optical reflector 408b, the first reverse movable optical reflector 408c, the second The optical parameters of the reverse movable optical mirror 408d are consistent; the scanning range L of the table top of the position scanning device 408 can meet the requirements of the first demodulation interferometer 4A and the second demodulation interferometer when the film thickness measurement probe module is not inserted into the film to be measured. Both instruments 4B can realize optical path matching of light reflected by different probe lens surfaces; the first demodulation interferometer 4A and the second demodulation interferometer 4B share the same position scanning device 408; when the first forward movable optical mirror 408a When the second forward movable optical reflector 408c is at the zero position, the first reverse movable optical reflector 408b and the second reverse movable optical reflector 408d have a maximum displacement L, and the first reverse movable optical reflector 408d has a maximum displacement L. When the mirror 408b and the second reverse movable optical reflector 408d are at the zero position, the first forward movable optical reflector 408a and the second forward movable optical reflector 408c have a maximum displacement L; during the scanning process, the first The forward movable optical reflector 408a, the second forward movable optical reflector 408b, the first reverse movable optical reflector 408c, and the second reverse optical reflector 408d have the same displacement;

The first photodetector 503 is connected with the 11a output end of the 3rd wavelength division multiplexer 11 in the acquisition and control module 5, and the 2nd photodetector 504 is connected with the 11b output end of the 2nd wavelength division multiplexer 11; The photodetector 505 is connected to the output terminal 12 a of the third wavelength division multiplexer 12 , and the fourth photodetector 506 is connected to the output terminal 12 b of the third wavelength division multiplexer 12 . The photodetector transmits the collected signal to the computer 501 through the data acquisition card 502. In addition, the computer 501 is also responsible for driving the position scanning device 408 to complete the optical path scanning.

Optical interferometry is currently the most accurate distance measurement method, but due to the long coherence length of the laser light source, laser interferometry cannot achieve absolute measurement. White-light interferometry methods use low-coherence, broad-spectrum light sources. Since the coherence length of the low-coherence light source is very small, the shape of the output interference fringe after interference is a sinusoidal oscillation modulated by a Gaussian envelope. The fringe has a main maximum value, which corresponds to zero optical path difference between the two arms of the interferometer. s position. Due to the strict requirements on the optical path difference between the two arms of the interferometer, the position of the central fringe provides a high-quality reference position for the measurement of physical quantities, and the absolute amount of the change of the measured physical quantity can be obtained according to the change of the position of the central fringe. Therefore, the measurement of the physical quantity in the white light interferometry system is transformed into the measurement of the position change of the central fringe of the interference signal. The present invention adopts the design of dual light sources, as shown in Figure 5, during the scanning process of the position scanning device, the white light interference signal and the laser interference signal are recorded simultaneously, and by reading the number of fringes of the laser interference signal, the position of the position scanning device can be Move the actual distance for high-precision calibration.

A device and measurement method for simultaneous measurement of film thickness and refractive index. When the film to be measured is not inserted, the first measurement probe 301 returns light to measure the distance between the two probes as an example to illustrate the distance measurement method used in the present invention:

The internal reflected light 311 of the first measurement probe 301 and the external surface reflected light 312 of the second measurement probe 302 are divided into two paths by the first demodulation interferometer coupler 407: one path enters into the first collimating mirror 403, the first positive direction In the reflective system that movable reflector 408a, the 2nd collimating mirror 404 and the 1st Faraday reflector 401 form, produce 311 ' and 312 ' reflection light; In the reflection system composed of the moving mirror 408b, the sixth collimating mirror 411 and the third Faraday mirror 414, 311" and 312" reflected lights are generated. Under the control of the computer 501, the position scanning device 408 drives the first forward movable mirror 408a and the first reverse movable mirror 408b to scan the optical path, as shown in Figure 6, the generation process of the wide-spectrum optical interference signal is :

(1) When the optical path difference between the two arms is equal to 2H, the light 311' in the scanning arm matches the light 312" in the fixed arm, and the first maximum white light interference signal 331 is generated.

(2) When the optical path difference between the two arms is equal to 0, in the scanning arm and the fixed arm, the light 311' and the light 311", and the light 312' and the light 312" are matched, and the main maximum white light interference signal 332 is generated.

(3) When the optical path difference between the two arms is equal to -2H, the light 312' in the scanning arm matches the light 312" in the fixed arm, and the second maximum white light interference signal 333 is generated.

(4) By extracting the position of the central fringe of the white light interference signal, using the traceability characteristics of the laser interference signal to obtain the absolute difference in scanning distance between the main maximum and the secondary maximum, and then obtain the first measuring probe 301 and the second measuring probe The absolute optical path between 302.

The thickness measurement method of the opaque film to be measured 303 based on the above broadband light interferometry method is:

(1) When the opaque film 303 to be measured is not inserted, the optical path position scanning device 408 is driven to scan the optical path, so that the internal reflected light 311 of the first measuring probe 301 and the outgoing light of the first measuring probe 301 are outside the second measuring probe 302 The surface reflected light 312 performs optical path matching, and the second measuring probe 302 internally reflected light 321 and the second measuring probe 302 outgoing light perform optical path matching on the first measuring probe 301 outer surface reflected light 322; through the acquisition and control module 5 pairs of correlation The parameters are demodulated and recorded to obtain the optical path H between the two measuring probes;

(2) Insert the opaque film to be measured 303 into the middle of the first measuring probe 301 and the second measuring probe 302, so that the opaque film to be measured 303 is perpendicular to the outgoing rays of the first measuring probe 301 and the second measuring probe 302; drive the optical path position The scanning device 408 scans the optical path, so that the internal reflection light 413 of the first measurement probe 301 and the light emitted by the first measurement probe 301 are reflected on the front surface 303a of the opaque film to be measured for optical path matching, and the internal reflection of the second measurement probe 302 The light 323 and the light emitted by the second measurement probe 302 perform optical path matching on the back surface 303b of the opaque film to be tested; Measuring the double optical path H1 of the front surface 303a of the film, the double optical path H2 of the second measuring probe 302 and the opaque film front surface 303b to be measured;

(3) The thickness d1 of the opaque film to be measured 303 can be determined by the above two measured values,

The thickness of the transparent film to be measured 304 and the method for measuring the refractive index are:

(1) When the transparent film 304 to be measured is not inserted, the optical path position scanning device 408 is driven to scan the optical path, so that the reflected light 311 inside the first measuring probe 301 and the outgoing light of the first measuring probe 301 are outside the second measuring probe 302 The surface reflected light 312 performs optical path matching, and the second measuring probe 302 internally reflected light 321 and the second measuring probe 302 outgoing light perform optical path matching on the first measuring probe 301 outer surface reflected light 322; through the acquisition and control module 5 pairs of correlation The parameters are demodulated and recorded to obtain the double optical path H between the two measuring probes;

(2) Insert the transparent film to be measured 304 into the middle of the first measuring probe 301 and the second measuring probe 302, the transparent film to be measured 304 is perpendicular to the outgoing rays of the first measuring probe 301 and the second measuring probe 302; drive optical path position scanning The device 408 scans the optical path, so that the internal reflection light 315 of the first measuring probe 301, the outgoing light of the first measuring probe 301 reflects the light 316 on the front surface 304a of the transparent film to be measured, and the outgoing light of the first measuring probe 301 is behind the transparent film to be measured The reflected light 317 of the surface 304b carries out optical path matching respectively, so that the internal reflected light 325 of the second measuring probe 302, the outgoing light of the second measuring probe 302 are reflected on the back surface 304b of the transparent film to be measured 326, and the outgoing light of the second measuring probe 302 is in the transparent The reflected light 327 on the front surface 304a of the film to be tested is respectively matched to the optical path; the relevant parameters are demodulated and recorded by the acquisition and control module 5, and the double optical path length H3 of the first measuring probe 301 and the transparent front surface 304a of the film to be tested are respectively obtained , the double optical path H4 between the first measuring probe 301 and the back surface 304b of the transparent film to be measured, the double optical path H5 between the second measuring probe 302 and the back surface 304b of the transparent film to be measured, the second measuring probe 302 and the transparent film to be measured Double the optical path H6 of the film front surface 304a;

(3) The thickness d2 of the transparent film to be measured 304 can be determined by the above-mentioned two measurements, i.e. d2=1/2[H-(H3+H5)]; The rate n can be determined by the above two measurements,

which is

The beneficial effects of the present invention are:

The invention directly inputs the narrow-linewidth laser light source into the demodulation interferometer, further avoids the influence of laser transmitted light and multiple laser reflections on the quality of the interference signal, and improves the accuracy of film thickness traceability;

By controlling the length of the tail fiber of the film thickness measuring probe, the present invention avoids the interference of the broad-spectrum light transmitted light in the film thickness measuring probe module on the recognition of the characteristic signal peak, reduces the difficulty of recognition, and further improves the accuracy of characteristic signal recognition.

The present invention adopts the design of double probes, which can simultaneously measure the thickness of the film and the refractive index of the film without contact;

The dual-light source common optical path and differential optical path structure design of the present invention can further reduce the influence of external environment disturbance on the film thickness measurement result;

Description of drawings

Fig. 1 is a schematic diagram of a device for simultaneous measurement of film thickness and refractive index;

Figure 2 is a diagram of the internal optical path of the measuring probe module when the film to be measured is not loaded;

Fig. 3 is a diagram of the internal optical path of the measuring probe module when the opaque film to be tested is loaded;

Fig. 4 is the internal optical path diagram of the measuring probe module when loading the transparent film to be tested;

Fig. 5 is a schematic diagram of the principle of laser interference signal traceability;

Fig. 6 is a schematic diagram of a distance measurement method based on the principle of white light interference when the film to be tested is not loaded.

Detailed ways

The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing:

Embodiment one:

The overall technical scheme of the present invention is shown in Figure 1. The wide-spectrum light output module 1 is composed of a wide-spectrum light source 101 with a center wavelength of 1310nm and a first isolator 102 with an operating wavelength of 1310nm. The wide-spectrum light source 101 is used as a measurement light source and is mainly used to achieve absolute measurement of film thickness; The wide laser output module is composed of a narrow linewidth laser light source 201 with a wavelength of 1550nm and a second isolator 202 with an operating wavelength of 1550nm. The narrow linewidth frequency-stabilized laser light source 103 is used as the optical path correction light source, mainly used to realize the traceability of film thickness measurement . The light emitted by the wide-spectrum light source 101 enters the beam-splitting coupler 2 with a splitting ratio of 3dB through the first isolator 102, and is divided into two paths, passing through the first circulator 11 with a working wavelength of 1310nm and the circulator with a working wavelength of 1310nm respectively. The second circulator 13 enters in the film thickness measuring probe module 3; the ratio of the first measuring probe 301 and the second measuring probe 302 lens end face reflectivity to the transmittance is 50:50, from the first measuring probe 401 and the second measuring The measurement light returned by the probe 402 passes through the first circulator 11 with a working wavelength of 1310nm and the second circulator 13 with a working wavelength of 1310nm and enters the first wavelength division multiplexer 8 with a working wavelength of 1310nm and 1550nm and a working wavelength of 1310nm respectively. and the relevant wavelength input end of the second wavelength division multiplexer 9 at 1550nm; the output light of the narrow-linewidth laser output module 2 with a wavelength of 1550nm is divided into two paths by the second beam splitting coupler 7 and enters the working wavelength at 1310nm and The first wavelength division multiplexer 8 at 1550nm and the relevant wavelength input ports of the second wavelength division multiplexer 9 at 1310nm and 1550nm at operating wavelength; the first wavelength division multiplexer 8 at 1310nm and 1550nm at working wavelength and 1310nm at the operating wavelength The two beams combined with the 1550nm second wavelength division multiplexer 9 are respectively input into the demodulation interferometer module 4, and the first demodulation interferometer 4A in the demodulation interferometer module 4 interferes with the second demodulation interferometer The scanning of the instrument 4B realizes optical path matching respectively; the 1310nm and 1550nm 3rd wavelength division multiplexer 11 and the 1310nm and 1550nm 4th wavelength division multiplexer 12 will be the white light measurement beam with the center wavelength of 1310nm and The laser correction beam with a wavelength of 1550nm is separated and acquired by the first photodetector 503 , the second photodetector 504 , the third photodetector 505 and the fourth photodetector 506 . The photoelectric detector transmits the collected signal to the computer 501 for demodulation processing through the data acquisition card 502 , and the computer 501 is responsible for driving the position scanning device 408 at the same time.

When the film to be tested is not inserted, the output light of the wide-spectrum optical output module 1 is split by the first beam-splitting coupler 6 with a splitting ratio of 3dB, and the light passes through the first circulator 11 with a working wavelength of 1310nm and the first circulator 11 with a working wavelength of 1310nm respectively. The second circulator 13 enters into the film thickness measuring probe module 3 . As shown in Figure 2, the reflected light beam 311 from the inner surface of the lens of the first measurement probe 301 and the reflected light beam 312 from the outer surface of the lens of the second measurement probe 302 pass through the first circulator 11 with a working wavelength of 1310nm and enter into a working wavelength of 1310nm and 1310nm. 1550nm 1st wavelength division multiplexer 8 related wavelength input end; the light beam 321 internally reflected by the lens of the second measuring probe 302 and the external surface reflected light beam 322 of the lens of the first measuring probe 301 pass through the second circulator 13 with an operating wavelength of 1310nm Input to the relevant wavelength input ports of the second wavelength division multiplexer 9 with working wavelengths of 1310nm and 1550nm; the output light of the narrow linewidth laser output module 2 is split by the second beam splitting coupler 7 with a splitting ratio of 3dB and then respectively input to the working The first wavelength division multiplexer 8 with a wavelength of 1310nm and 1550nm and the relevant wavelength input end of the second wavelength division multiplexer 9 with an operating wavelength of 1310nm and 1550nm; through the first wavelength division multiplexer with an operating wavelength of 1310nm and 1550nm 8. After beam combining, the optical signal is input to the first demodulation interferometer 4A; after passing through the second wavelength division multiplexer 9 with operating wavelengths of 1310nm and 1550nm, the optical signal is input to the second demodulation interferometer 4B; The transmission mode in the first demodulation interferometer 4A is: the working wavelength is 1310nm and 1550nm. The first wavelength division multiplexer 8 inputs the optical signal to the first demodulation interferometer coupler 407 with a splitting ratio of 3dB and divides it into two beams. : one beam is transmitted through the first forward movable reflector 408a, reflected by the first Faraday reflector 401, and the other beam is transmitted through the first reverse movable reflector 408b, reflected by the third Faraday reflector 414, when the first When the forward optical scanning mirror 408a and the first reverse movable optical mirror 408b move, the optical paths of the reflected light 411 and the reflected light 412 are completely matched, and wide-spectrum optical interference fringes are formed on the first photodetector 503, and the Laser interference fringes are formed on the 2nd photodetector 504; the transmission mode of the light beam in the 2nd demodulation interferometer 6B is: the working wavelength is 1310nm and 1550nm, and the 2nd wavelength division multiplexer 9 inputs the optical signal to the optical signal with a splitting ratio of 3dB. The second demodulation interferometer coupler 409 is divided into two beams: one beam is transmitted through the second forward movable mirror 408c, reflected by the second Faraday mirror 402, and the other beam is passed through the second reverse movable mirror The transmission of 408d, the reflection of the 4th Faraday reflector 415, when the 2nd forward optical scanning reflector 408c and the 2nd reverse movable optical reflector 408d move, the optical paths of the reflected light 321 and the reflected light 322 completely match, in Broad-spectrum light interference fringes are formed on the third photodetector 505, and laser interference fringes are formed on the fourth photodetector 506. After demodulating the white light interference signal, the double optical path H between the two measuring probes can be obtained.

When the opaque film to be measured 303 is measured, as shown in FIG. 3 , the reflected light beam 313 from the inner surface of the lens of the first measuring probe 301 and the reflected light beam 314 from the front surface 303a of the opaque film to be measured are input into the first demodulation interferometer 6A; The light beam 323 reflected by the lens inner surface of the second measurement probe 302 and the light beam 324 reflected by the rear surface 303b of the film to be measured are input into the second demodulation interferometer 6B. The light beam is transmitted in the first demodulation interferometer 6A in the following way: the optical signal is input to the first demodulation interferometer coupler 407 with a splitting ratio of 3dB by the first wavelength division multiplexer 8 with operating wavelengths of 1310nm and 1550nm. There are two beams, one beam is transmitted by the first forward movable mirror 408a, reflected by the first Faraday mirror 401, and the other beam is transmitted by the first reverse movable mirror 408b and reflected by the third Faraday mirror 414, When the first forward optical scanning mirror 408a and the first reverse movable optical mirror 408b move, the optical paths of the reflected light 313 and the reflected light 314 are completely matched, and wide-spectrum optical interference is formed on the first photodetector 703 fringes, forming laser interference fringes on the second photodetector 704; the light beam is transmitted in the second demodulation interferometer 6B in the following way: the optical signal is input to the light splitter by the second wavelength division multiplexer 9 with operating wavelengths of 1310nm and 1550nm The second demodulation interferometer coupler 409 with a ratio of 3dB is divided into two beams, one beam is transmitted through the second forward movable reflector 408c, reflected by the second Faraday reflector 402, and the other beam is passed through the second reverse direction The transmission of the movable reflector 408d and the reflection of the fourth Faraday reflector 415, when the second forward optical scanning reflector 408c and the second reverse movable optical reflector 408d move, the reflected light 323 and the reflected light 324 have an optical path Completely matched, wide-spectrum light interference fringes are formed on the third photodetector 505 , and laser interference fringes are formed on the fourth photodetector 506 . By demodulating the wide-spectrum optical interference signal and the narrow-linewidth laser interference signal, the double optical path H1 of the first measuring probe 301 and the front surface 303a of the opaque film to be tested, the second measuring probe 302 and the opaque film to be tested are respectively obtained Double the optical path length H2 of the rear surface 303b. Therefore, the opaque film thickness d1 is determined by the above two measured values, namely

When the transparent film to be measured 304 is measured, as shown in Figure 4, the reflected light beam 315 from the inner surface of the lens of the first measurement probe 301, the reflected light beam 316 from the front surface 304a of the transparent film to be measured, and the reflected light beam 317 from the rear surface 304b of the transparent film to be measured are input to In the first demodulation interferometer 6A; the reflected light beam 325 from the inner surface of the lens of the second measurement probe 302, the reflected light beam 326 from the rear surface 304b of the transparent film to be measured, and the reflected light beam 327 from the front surface 304a of the transparent film to be measured are input to the second demodulation interference Instrument 6B. The light beam is transmitted in the first demodulation interferometer 6A in the following way: the optical signal is input to the first demodulation interferometer coupler 407 with a splitting ratio of 3dB by the first wavelength division multiplexer 8 with operating wavelengths of 1310nm and 1550nm. There are two beams, one beam is transmitted by the first forward movable mirror 408a, reflected by the first Faraday mirror 401, and the other beam is transmitted by the first reverse movable mirror 408b and reflected by the third Faraday mirror 414, When the first forward optical scanning mirror 408a and the first reverse movable optical mirror 408b move, the reflected light 315, the reflected light 316, and the reflected light 317 are completely matched in optical path respectively, and on the first photodetector 503 Broad-spectrum light interference fringes are formed, and laser interference fringes are formed on the second photodetector 504; the transmission mode of the light beam in the second demodulation interferometer 6B is: the working wavelength is 1310nm and the second wavelength division multiplexer 9 of 1550nm The optical signal is input into the second demodulation interferometer coupler 409 with a splitting ratio of 3dB and divided into two beams, one beam is transmitted through the second forward movable mirror 408c, reflected by the second Faraday mirror 402, and the other beam After the transmission of the second reverse movable reflector 408d and the reflection by the fourth Faraday reflector 415, when the second forward optical scanning reflector 408c and the second reverse movable optical reflector 408d move, the reflected light 325, reflected The optical paths of the light 326 and the reflected light 327 are completely matched respectively, and wide-spectrum light interference fringes are formed on the third photodetector 505 , and laser interference fringes are formed on the fourth photodetector 506 . By demodulating the wide-spectrum optical interference signal and the narrow-linewidth laser interference signal, the double optical path H3 of the first measuring probe 301 and the front surface 304a of the transparent film to be measured, the first measuring probe 301 and the transparent film to be measured are respectively obtained The double optical path H4 of the back surface 304b, the double optical path H5 of the second measuring probe 302 and the back surface 304b of the transparent film to be measured, the double optical path H6 of the second measuring probe 302 and the front surface 304a of the transparent film to be tested; The thickness d2 of the transparent film to be measured (304) can be determined by the above two measured values, namely When the refractive index of air is 1, the refractive index n of the transparent film to be measured (304) can be determined by the above two measured values,

which is

Embodiment two:

A device for simultaneous measurement of film thickness and refractive index consists of five parts: a wide-spectrum light output module 1, a narrow linewidth laser output module 2, a film thickness measurement probe module 3, a demodulation interferometer module 4, and an acquisition and control module 5. ;

The output light of the wide-spectrum light output module 1 is divided into two paths through the first beam splitter coupler 6 and enters the first measuring probe 301 and the second measuring probe 301 of the film thickness measuring probe module 3 through the first circulator 10 and the second circulator 13 respectively. In the measuring probe 302; the return light via the first measuring probe 301 and the second measuring probe 302 enters the first wavelength division multiplexer 8 and the second wavelength division multiplexer respectively through the first circulator 10 and the second circulator 11 9 relevant wavelength input terminals;

The output light of the narrow-linewidth laser output module 2 is divided into two paths through the second beam-splitting coupler 7 and enters the relevant wavelength input ports of the first wavelength division multiplexer 8 and the second wavelength division multiplexer 9 respectively; The two beams of light combined by the first wavelength division multiplexer 8 and the second wavelength division multiplexer 9 are respectively input into the demodulation interferometer module 4, and pass through the first demodulation interferometer 4A in the demodulation interferometer module 4 and the second demodulation interferometer 4B; the interference signals of different wavelengths passed through the third wavelength division multiplexer 11 and the fourth wavelength division multiplexer 12 are separated and input to the acquisition and control module 5 .

The characteristics of the light source in the wide-spectrum light output module 1 and the narrow-linewidth laser output module 2 are: the half-spectrum width of the wide-spectrum light source 101 is greater than 45nm, and the fiber output power is greater than 2mW; the half-spectrum width of the narrow-linewidth laser light source 201 The fiber output power is less than 1pm, and the fiber output power is greater than 2mW; the wide-spectrum light source 101 and the narrow-linewidth laser light source 201 have different central wavelengths, and the spectra of the two have no overlap within the half-spectrum width.

The film thickness measuring probe module 3 is composed of a first measuring probe 301 and a second measuring probe 302; the first measuring probe 301 and the second measuring probe 302 can simultaneously realize the transmission and reflection of the transmitted light, and the reflection of the transmitted light rate is between 20% and 80%; the outgoing rays of the first measuring probe 301 and the second measuring probe 302 coincide with each other; Vertical; the first measurement probe 301 is connected to the output end 10c of the first circulator 10, and the second measurement probe 302 is connected to the output end 13c of the second circulator 13.

The feature of the length of the tail fiber of the film thickness measurement probe in the film thickness measurement probe module 3 is that the length difference between the first measurement probe 301 and the second measurement probe 302 is greater than that of the optical path scanning device in the demodulation interferometer module 4 408 optical path scanning range.

Described demodulation interferometer module 4 is by the 1st Faraday reflector 401, the 2nd Faraday reflector 402, the 1st collimating mirror 403, the 2nd collimating mirror 404, the 3rd collimating mirror 405, the 4th collimating mirror 406, the first demodulation interferometer coupler 407, the optical path scanning device 408, the second demodulation interferometer coupler 409, the fifth collimating mirror 410, the sixth collimating mirror 411, the seventh collimating mirror 412, the first 8 collimating mirror 413, the third Faraday mirror 414 and the fourth Faraday mirror 415; the output end 8c of the first wavelength division multiplexer 8 is connected to the input end 4a of the first demodulation interferometer coupler 407 , the 4c output end of the first demodulation interferometer coupler 407 is connected with the first collimator mirror 403, the second collimator mirror 404 is connected with the first Faraday reflector 401, the first demodulation interferometer coupler 407 The 4d output end is connected to the fifth collimating mirror 410, and the sixth collimating mirror 411 is connected to the third Faraday reflector 414; the 9c output end of the second wavelength division multiplexer 9 is connected to the second demodulation interferometer coupler 409 The 4g input terminal of the 2nd demodulation interferometer coupler 409 is connected with the 4th collimating mirror 406, the 3rd collimating mirror 405 is connected with the 2nd Faraday mirror 402, the 2nd demodulation The 4h output end of the interferometer coupler 409 is connected to the 8th collimator mirror 413, and the 7th collimator mirror 412 is connected to the 4th Faraday reflector 415; the first demodulation interferometer coupler 407, the first collimator mirror 403 , the second collimating mirror 404, the first Faraday mirror 401, the first forward movable optical mirror 408a, the first reverse movable optical mirror 408b, the fifth collimating mirror 410, the sixth collimating mirror 411 , the third Faraday mirror 414 and the first demodulation interferometer 4A; the second demodulation interferometer coupler 409, the third collimator mirror 405, the fourth collimator mirror 406, the second Faraday mirror 402, the second Forward movable optical mirror 408c, the second reverse movable optical mirror 408d, the seventh collimator mirror 412, the eighth collimator mirror 413, the fourth Faraday mirror 415 and the second demodulation interferometer 4B; The first collimating mirror 403, the second collimating mirror 404, the third collimating mirror 405, the fourth collimating mirror 406, the fifth collimating mirror 410, the sixth collimating mirror 411, the seventh collimating mirror 412, the 8 The optical parameters of the collimating mirror 413 are consistent; the optical parameters of the first Faraday mirror 401, the second Faraday mirror 402, the third Faraday mirror 414, and the fourth Faraday mirror 415 are consistent.

The feature of the optical path scanning device 408 in the described demodulation interferometer module 4 is: the 1st forward movable optical reflector 408a, the 2nd forward movable optical reflector 408b, the 1st reverse movable optical reflector The optical parameters of the mirror 408c and the second reverse movable optical mirror 408d are consistent; the optical path scanning range L of the position scanning device 408 can meet the requirements of the first demodulation interference when the film thickness measurement probe module 4 is not inserted into the film to be measured. Both the instrument 4A and the second demodulation interferometer 4B can realize the optical path matching of the reflected light from different probe lens surfaces; the first demodulation interferometer 4A and the second demodulation interferometer 4B share the same position scanning device 408; when the first When the forward movable optical reflector 408a and the second forward movable optical reflector 408c are at the zero position, the first reverse movable optical reflector 408b and the second reverse movable optical reflector 408d have a maximum displacement L, When the first reverse movable optical reflector 408b and the second reverse movable optical reflector 408d are at the zero position, the first forward movable optical reflector 408a and the second forward movable optical reflector 408c have the maximum displacement L; in the scanning process, the 1st forward movable optical reflector 408a, the 2nd forward movable optical reflector 408b, the 1st reverse movable optical reflector 408c, the 2nd reverse optical reflector 408d have the same displacement.

The method for measuring the thickness of the opaque film is:

(1) When the opaque film 303 to be measured is not inserted, the optical path position scanning device 408 is driven to scan the optical path, so that the internal reflected light 311 of the first measuring probe 301 and the outgoing light of the first measuring probe 301 are outside the second measuring probe 302 The optical path matching is performed on the surface reflected light 312, and the optical path matching is performed on the internal reflected light 321 of the second measuring probe 302 and the emitted light of the second measuring probe 302, and the reflected light 322 on the outer surface of the first measuring probe 301; through the collection and control module 5 pairs of related parameters Perform demodulation and recording to obtain the double optical path H between the two measuring probes;

(2) Insert the opaque film to be measured 303 into the middle of the first measuring probe 301 and the second measuring probe 302, so that the opaque film to be measured 303 is perpendicular to the outgoing rays of the first measuring probe 301 and the second measuring probe 302; drive the optical path position The scanning device 408 performs optical path scanning, so that the internal reflected light 313 of the first measuring probe 301 and the emitted light of the first measuring probe 301 are matched in optical path with the reflected light 314 on the front surface 303a of the opaque film to be measured, and the internal reflected light of the second measuring probe 302 323 and the light emitted by the second measuring probe 302 perform optical path matching on the back surface 303b of the opaque film to be measured; the relevant parameters are demodulated and recorded by the acquisition and control module 5, and the first measuring probe 301 and the opaque film to be tested are obtained respectively. The double optical path H1 of the front surface 303a of the film, the double optical path H2 of the second measuring probe 302 and the front surface 303b of the opaque film to be measured;

(3) The thickness d1 of the opaque film to be measured 303 can be determined by the above two measured values,

which is

A device and method for simultaneously measuring film thickness and refractive index, comprising the following steps:

(1) When the transparent film 304 to be measured is not inserted, the optical path position scanning device 408 is driven to scan the optical path, so that the reflected light 311 inside the first measuring probe 301 and the outgoing light of the first measuring probe 301 are outside the second measuring probe 302 The surface reflected light 312 performs optical path matching, and the second measuring probe 302 internally reflected light 321 and the second measuring probe 302 outgoing light perform optical path matching on the first measuring probe 301 outer surface reflected light 322; through the acquisition and control module 5 pairs of correlation The parameters are demodulated and recorded to obtain the double optical path H between the two measuring probes;

(2) Insert the transparent film 304 to be measured into the middle of the first measuring probe 301 and the second measuring probe 302, so that the transparent film 304 to be measured is perpendicular to the outgoing rays of the first measuring probe 301 and the second measuring probe 302; drive the optical path position The scanning device 408 scans the optical path, so that the internal reflection light 315 of the first measuring probe 301, the light emitted by the first measuring probe 301 is reflected on the front surface 304a of the transparent film to be measured, and the light 316 emitted by the first measuring probe 301 is reflected on the transparent film to be measured. The reflected light 317 of the back surface 304b is respectively carried out optical path matching, so that the reflected light 325 inside the second measuring probe 302 and the outgoing light of the second measuring probe 302 are reflected on the back surface 304b of the transparent film to be measured 326, and the outgoing light of the second measuring probe 302 is in the The reflected light 327 on the front surface 304a of the transparent film to be tested is matched with the optical path respectively; the relevant parameters are demodulated and recorded by the acquisition and control module 5, and the optical path lengths of the first measuring probe 301 and the front surface 304a of the transparent film to be tested are obtained respectively H3, the first measurement probe 301 and the double optical path H4 of the transparent film back surface 304b to be measured, the second measurement probe 302 and the double light path H5 of the transparent film back surface 304b to be measured, the second measurement probe 302 and the transparent film to be tested Measure the double optical path H6 of 30ab on the front surface of the film;

(3) When the refractive index of air is 1, the thickness d2 of the transparent film to be measured 304 can be determined by the above two measured values,

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. A device and measurement method for simultaneous measurement of film thickness and refractive index, characterized in that: a device for simultaneous measurement of film thickness and refractive index consists of a wide-spectrum light output module (1), a narrow linewidth laser output module (2 ), a film thickness measurement probe module (3), a demodulation interferometer module (4) and an acquisition and control module (5) consisting of five parts; The output light of the wide-spectrum light output module (1) is divided into two paths through the first beam splitting coupler (6) and enters the film thickness measurement probe module (3) through the first circulator (10) and the second circulator (13) respectively. ) of the first measuring probe (301) and the second measuring probe (302); the return light via the first measuring probe (301) and the second measuring probe (302) passes through the first circulator (10), the second annular Device (11) enters the relevant wavelength input end of the 1st wavelength division multiplexer (8) and the 2nd wavelength division multiplexer (9) respectively; The output light of the narrow linewidth laser output module (2) is divided into two paths through the second beam splitter coupler (7) and enters the first wavelength division multiplexer (8) and the second wavelength division multiplexer (9) respectively The relevant wavelength input port of the relevant wavelength; after the first wavelength division multiplexer (8) and the second wavelength division multiplexer (9) combine the two beams of light respectively to input in the demodulation interferometer module (4), through the demodulation The first demodulation interferometer (4A) and the second demodulation interferometer (4B) in the interferometer module (4); through the 3rd wavelength division multiplexer (11) and the 4th wavelength division multiplexer (12 ) and separate the interference signals of different wavelengths into the acquisition and control module (5). 2. A device and method for simultaneously measuring film thickness and refractive index according to claim 1, characterized in that, in the wide-spectrum light output module (1) and the narrow linewidth laser output module (2) The characteristics of the light source are: the half-spectrum width of the wide-spectrum light source (101) is greater than 45nm, and the fiber output power is greater than 2mW; the half-spectrum width of the narrow-linewidth laser light source (201) is less than 1pm, and the fiber output power is greater than 2mW; ) and the narrow-linewidth laser light source (201) have different center wavelengths, and the spectra of the two have no overlapping part within the half-spectrum width. 3. The device and method for simultaneously measuring film thickness and refractive index according to claim 1, characterized in that: the film thickness measuring probe module (3) consists of a first measuring probe (301) and a second measuring probe (301). Composed of measuring probes (302); the first measuring probe (301) and the second measuring probe (302) can realize the transmission and reflection of the transmitted light at the same time, and the reflectivity of the transmitted light is between 20% and 80%; the first The outgoing rays of the measuring probe (301) and the second measuring probe (302) coincide with each other; when the device under test is placed for measurement, they are perpendicular to the outgoing rays of the first measuring probe (301) and the second measuring probe (302); The measuring probe (301) is connected to the output end (10c) of the first circulator (10), and the second measuring probe (302) is connected to the output end (13c) of the second circulator (13). 4. a kind of film thickness according to claim 3 and the device and measuring method of refractive index simultaneous measurement, it is characterized in that, the film thickness measurement probe tail fiber length in the described film thickness measurement probe module (3) is characterized in that : The length difference between the pigtails of the first measuring probe (301) and the second measuring probe (302) is greater than the optical path scanning range of the optical path scanning device (408) in the demodulation interferometer module (4). 5. The device and measuring method for simultaneous measurement of film thickness and refractive index according to claim 1, characterized in that: the demodulation interferometer module (4) consists of the first Faraday reflector (401), the second 2 Faraday reflectors (402), the first collimator mirror (403), the second collimator mirror (404), the third collimator mirror (405), the fourth collimator mirror (406), the first demodulation interferometer Coupler (407), optical path scanning device (408), the 2nd demodulation interferometer coupler (409), the 5th collimating mirror (410), the 6th collimating mirror (411), the 7th collimating mirror ( 412), the 8th collimating mirror (413), the 3rd Faraday reflector (414) and the 4th Faraday reflector (415); 1 The (4a) input end of the demodulation interferometer coupler (407) is connected, the (4c) output end of the first demodulation interferometer coupler (407) is connected with the first collimating mirror (403), the second The collimating mirror (404) is connected with the first Faraday reflector (401), the (4d) output end of the first demodulation interferometer coupler (407) is connected with the fifth collimating mirror (410), and the sixth collimating mirror The mirror (411) is connected with the 3rd Faraday mirror (414); the (9c) output of the 2nd wavelength division multiplexer (9) and the (4g) input of the 2nd demodulation interferometer coupler (409) The (4e) output of the 2nd demodulation interferometer coupler (409) is connected with the 4th collimating mirror (406), and the 3rd collimating mirror (405) is connected with the 2nd Faraday reflector (402) Connect, the (4h) output end of the 2nd demodulation interferometer coupler (409) the 8th collimating mirror (413) is connected, the 7th collimating mirror (412) is connected with the 4th Faraday reflector (415); The first demodulation interferometer coupler (407), the first collimating mirror (403), the second collimating mirror (404), the first Faraday mirror (401), the first forward movable optical mirror (408a ), the 1st reverse movable optical reflector (408b), the 5th collimator mirror (410), the 6th collimator mirror (411), the 3rd Faraday reflector (414) and constitute the 1st demodulation interferometer ( 4A); the second demodulation interferometer coupler (409), the third collimator mirror (405), the fourth collimator mirror (406), the second Faraday reflector (402), the second forward movable optical reflector mirror (408c), the 2nd reverse movable optical reflector (408d), the 7th collimator mirror (412), the 8th collimator mirror (413), the 4th Faraday reflector (415) and constitute the 2nd demodulator Interferometer (4B); 1st collimating mirror (403), 2nd collimating mirror (404), 3rd collimating mirror (405), 4th collimating mirror (406), 5th collimating mirror (410) , the optical parameters of the 6th collimating mirror (411), the 7th collimating mirror (412), and the 8th collimating mirror (413); the 1st Faraday reflector (401), the 2nd Faraday reflector (4 02), the optical parameters of the 3rd Faraday reflector (414), and the 4th Faraday reflector (415) are consistent. 6. The device and measuring method for simultaneous measurement of film thickness and refractive index according to claim 4, characterized in that, the optical path scanning device (408) in the demodulation interferometer module (4) Features: first forward movable optical reflector (408a), second forward movable optical reflector (408b), first reverse movable optical reflector (408c), second reverse movable optical reflector The optical parameters of the mirror (408d) are consistent; the optical path scanning range (L) of the position scanning device (408) can meet the requirements of the first demodulation interferometer (4A) when the film thickness measurement probe module (4) is not inserted into the film to be measured. Both the second demodulation interferometer (4B) and the second demodulation interferometer (4B) can realize the optical path matching of the reflected light from different probe lens surfaces; the first demodulation interferometer (4A) and the second demodulation interferometer (4B) share the same position scanning device ( 408); when the 1st forward movable optical reflector (408a) and the 2nd forward movable optical reflector (408c) were at zero position, the 1st reverse movable optical reflector (408b) and the 2nd reflector There is a maximum displacement (L) towards the movable optical reflector (408d), and when the first reverse movable optical reflector (408b) and the second reverse movable optical reflector (408d) are at the zero position, the first positive direction The movable optical mirror (408a) and the second forward movable optical mirror (408c) have a maximum displacement (L); during the scanning process, the first forward movable optical mirror (408a), the second forward movable optical mirror The moving optical mirror (408b), the first reverse movable optical mirror (408c), and the second reverse optical mirror (408d) have the same displacement. 7. The device and method for simultaneously measuring film thickness and refractive index according to claim 1, wherein the method for measuring the thickness of an opaque film is: (1) When the opaque film to be measured (303) is not inserted, the optical path position scanning device (408) is driven to scan the optical path, so that the internal reflection light (311) of the first measuring probe (301) and the first measuring probe (301) ) outgoing light is reflected on the outer surface of the second measuring probe (302) (312) for optical path matching, the internal reflected light (321) of the second measuring probe (302) and the second measuring (302) probe outgoing light first measuring probe (301) The external surface reflected light (322) performs optical path matching; the relevant parameters are demodulated and recorded by the acquisition and control module (5), and the double optical path H between the two measuring probes is obtained; (2) Insert the opaque film to be measured (303) into the middle of the first measuring probe (301) and the second measuring probe (302), so that the opaque film to be measured (303) and the first measuring probe (301) and the second measuring probe The outgoing light of (302) is vertical; the optical path position scanning device (408) is driven to carry out optical path scanning, so that the internal reflection light (313) of the first measuring probe (301) and the outgoing light of the first measuring probe (301) are in the opaque to-be-measured The reflected light (314) on the front surface of the film (303a) performs optical path matching, the internal reflected light (323) of the second measuring probe (302) and the outgoing light of the second measuring probe (302) are reflected on the back surface (303b) of the opaque film to be measured The light (324) performs optical path matching; the relevant parameters are demodulated and recorded through the acquisition and control module (5), and the double optical path H1 of the first measuring probe (301) and the front surface of the opaque film to be measured (303a) are respectively obtained , the second measuring probe (302) and the double optical path H2 of the front surface (303b) of the opaque film to be measured; (3) The thickness d1 of the opaque film to be tested (303) can be determined by the above two measured values, namely 8. The device and method for simultaneously measuring film thickness and refractive index according to claim 1, wherein the device and method for simultaneously measuring film thickness and refractive index comprise the following steps: (1) When the transparent film to be measured (304) is not inserted, the optical path position scanning device (408) is driven to scan the optical path, so that the internal reflection light (311) of the first measuring probe (301) and the first measuring probe (301) ) the light emitted by the second measuring probe (302) is reflected on the outer surface (312) for optical path matching, and the internal reflected light (321) of the second measuring probe (302) and the emitted light of the second measuring probe (302) are measured in the first measurement The optical path matching is performed on the reflected light (322) on the outer surface of the probe (301); the relevant parameters are demodulated and recorded by the acquisition and control module (5), and the double optical path H between the two measuring probes is obtained; (2) Insert the transparent film to be measured (304) into the middle of the first measuring probe (301) and the second measuring probe (302), so that the transparent film to be measured (304) and the first measuring probe (301) and the second measuring probe The outgoing light of (302) is vertical; the optical path position scanning device (408) is driven to carry out optical path scanning, so that the internal reflection light (315) of the first measuring probe (301) and the outgoing light of the first measuring probe (301) are transparent to be measured The reflected light (316) on the front surface of the film (304a), the light emitted by the first measuring probe (301) and the reflected light (317) on the back surface (304b) of the transparent film to be tested are respectively subjected to optical path matching, so that the second measuring probe (302) Internally reflected light (325), light emitted by the second measurement probe (302) is reflected on the back surface (304b) of the transparent film to be measured (326), light emitted by the second measurement probe (302) is on the front surface (304a) of the transparent film to be measured ) reflected light (327) respectively carry out optical path matching; through the acquisition and control module (5) to demodulate and record the relevant parameters, respectively obtain twice Optical path H3, double optical path H4 between the first measuring probe (301) and the back surface of the transparent film to be measured (304b), double optical path between the second measuring probe (302) and the back surface (304b) of the transparent film to be tested H5, the second measuring probe (302) and the double optical path H6 of the front surface (30ab) of the transparent film to be measured; (3) When the refractive index of air is 1, the thickness d2 of the transparent film to be measured (304) can be determined by the above two measured values, namely The refractive index n of the transparent film to be measured (304) can be determined by the above two measured values, namely