Submicron-sized foreign matter nondestructive detection device and submicron-sized foreign matter nondestructive detection methodTechnical Field
The disclosure relates to the technical field of medium laser optical detection, in particular to a submicron-level foreign matter nondestructive detection device and a submicron-level foreign matter nondestructive detection method.
Background
Integrated circuits, discrete devices, sensors, optoelectronic devices, etc., related to micro-nano fabrication and device related fields involve the application, fabrication, and removal of large amounts of sub-micron substances. Improper control and removal of nonfunctional foreign matter introduced by materials and environmental factors during fabrication can affect the functionality and reliability of device applications, which are critical factors requiring strict control during fabrication. And with the continuous development and refinement of micro-nano process, the control requirements on the types, sizes and quantity of the foreign matters are more strict.
At present, in the process of manufacturing the micro-nano device, pure optical means and visual means are often adopted to detect foreign matters and defects, and only micron-sized resolution can be realized. In the foreign matter analysis process of the failure device, the device is often required to be disassembled under specific requirements, and a microscopic infrared spectrometer is adopted to analyze chemical components, detect the surface morphology and the dimension with high resolution by an electron microscope, analyze the element composition of the organic matters by an X-ray energy spectrum, measure the dimension and the surface roughness of the organic matters by an atomic force microscope, analyze the chemical composition and the bonding state of the organic matters by an X-ray photoelectron energy spectrum, measure the thickness and the optical properties of the organic matters by an ellipsometer and the like. Due to the functional limitations of the above technology in resolution, sensitivity, suitability for device (wafer) detection, timeliness of detection, etc., nondestructive detection of rapid scanning of submicron-sized foreign matters in the manufacturing process cannot be realized.
In view of this, a new micro-nano foreign matter nondestructive testing device and method are needed in the market to solve the problem that the micro-nano device in the prior art cannot realize rapid nondestructive testing of submicron foreign matter in the manufacturing process.
Disclosure of Invention
The embodiment of the disclosure provides a submicron-level foreign matter nondestructive detection device and a submicron-level foreign matter nondestructive detection method, which aim to solve the problem that a micro-nano device in the prior art cannot realize rapid nondestructive detection of submicron-level foreign matters in a manufacturing process.
The submicron-level foreign matter nondestructive detection device provided by the embodiment of the disclosure comprises a movable carrier, a middle infrared laser, a laser vibration meter and a signal processing module;
The movable carrier can move the sample piece to be tested along a plurality of different directions;
The middle infrared laser is used for emitting middle infrared lasers with different wavelengths to the sample piece to be detected;
The laser vibration meter comprises a beam splitter, a beam combiner and a photoelectric detector which are sequentially arranged in a self light path;
The signal processing module is electrically connected with the laser vibration meter and is used for receiving and processing the measurement signals of the laser vibration meter;
the beam splitter can split laser emitted by the laser vibration meter into detection laser and reference laser, and the detection laser can be reflected, refracted or scattered back to the laser vibration meter after being irradiated on a sample piece to be detected;
the beam combiner is used for combining the reference laser and the reflected, refracted or scattered detection laser;
the photoelectric detector is used for detecting the interference frequency difference of the combined laser and converting the interference frequency difference into an electric signal for vibration of the sample to be detected.
In an embodiment, the mid-infrared laser can irradiate the mid-infrared laser to the sample to be measured through a first light path;
a first dichroic mirror, a second dichroic mirror and a reflecting objective lens are sequentially arranged in the first light path at intervals along the irradiation direction;
the mid-infrared laser light can respectively penetrate through the first dichroic mirror and the second dichroic mirror;
The detection laser can be reflected to a sample piece to be detected through the second dichroic mirror in a reversing way or reflected back to the laser vibration meter in a reversing way;
The reflecting objective lens is used for focusing the middle infrared laser and the detection laser on the surface of the sample piece to be detected.
In an embodiment, the device further comprises a focusing lens and a photosensitive coupling component which are arranged corresponding to the first dichroic mirror;
The sample piece to be tested can reflect the middle infrared laser light to the first dichroic mirror along the first light path partially, and the first dichroic mirror can reflect the reflected middle infrared laser light to the focusing lens;
the focusing lens is used for focusing the mid-infrared laser reflected by the first dichroic mirror on the photosensitive coupling assembly.
In one embodiment, the laser vibrometer further comprises a helium-neon laser and an acousto-optic modulator;
the helium-neon laser is used for emitting laser towards the beam splitter and is used for detecting laser and reference laser through the beam splitter;
the reference laser beam is irradiated to the beam combiner after passing through the acousto-optic modulator.
In one embodiment, the signal processing module includes a lock-in amplifier and a processor;
The phase-locked amplifier is electrically connected with the photoelectric detector and is used for phase-locking the signal vibration measured by the photoelectric detector;
The processor is electrically connected with the phase-locked amplifier and can draw a vibration intensity image according to phase-locked data of the phase-locked amplifier.
In an embodiment, the processor is further electrically connected to the mid-infrared laser, and is capable of controlling the mid-infrared laser to output the mid-infrared laser with a plurality of equidistant wavelengths one by one.
In an embodiment, the processor is further electrically connected to the mobile carrier, and is capable of controlling the mobile carrier to perform scanning movement along a preset track path and a preset speed.
In addition, the embodiment of the disclosure also provides a submicron-sized foreign matter nondestructive testing method, which can be applied to the submicron-sized foreign matter nondestructive testing device, and comprises the following steps:
The method comprises the steps that firstly, a sample piece to be detected is fixedly placed on a movable carrying platform, and the movable carrying platform is adjusted to be moved so that the sample to be detected is accurately located in a detection focus area;
The second step, the detection laser is emitted to the sample piece to be detected through the laser vibration meter, and the signal processing module selects the boundary of the area to be detected in the sample to be detected based on the optical imaging picture of the laser vibration meter and generates a mobile scanning filling path of the mobile carrier;
And thirdly, transmitting middle infrared laser with repetition frequency to a sample to be detected through a middle infrared laser, selecting a plurality of equidistant wavelengths in the spectrum range of the middle infrared laser to be output one by one, operating detection tasks one by the laser vibration meter under each wavelength, and drawing vibration intensity distribution images by the signal processing module according to the plurality of wavelengths of the middle infrared laser.
In one embodiment, the submicron order foreign matter nondestructive testing method further comprises:
And a follow-up step, namely adjusting and selecting the wavelength of the middle infrared laser emitted by the middle infrared laser according to the wave crest in the vibration intensity distribution image, and carrying out random selective detection or whole-surface detection on other positions of the sample piece to be detected.
In one embodiment, the submicron order foreign matter nondestructive testing method further comprises:
And a foreign matter component analysis step, namely setting a scanning output period of the middle infrared laser, recording a signal intensity spectrum under the middle infrared laser by a lock-in amplifier to obtain the wavelength of the vibration peak position of the foreign matter material, and analyzing and judging the foreign matter material component according to the position of the infrared absorption fingerprint peak of the common chemical bond.
Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:
The submicron-level foreign matter nondestructive detection device provided by the embodiment of the disclosure can realize submicron-level detection of the foreign matter on the surface of the sample to be detected, does not have any destructiveness on the sample to be detected in the whole detection process, does not need to perform any additional pre-detection processing such as cutting and extraction on the sample to be detected, is suitable for online detection operation of a sample to be detected assembly line, and has the advantages of high detection precision, high detection efficiency and capability of realizing rapid detection and evaluation analysis on the foreign matter on the surface of a large-size device.
In addition, the submicron-level foreign matter nondestructive testing method provided by the embodiment of the disclosure can be suitable for the submicron-level foreign matter nondestructive testing device, and can achieve the same beneficial effects.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following specification.
Drawings
The above, as well as additional purposes, features, and advantages of exemplary embodiments of the present disclosure will become readily apparent from the following detailed description when read in conjunction with the accompanying drawings. Several embodiments of the present disclosure are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which:
in the drawings, the same or corresponding reference numerals indicate the same or corresponding parts.
FIG. 1 shows a schematic diagram of a submicron-sized foreign matter nondestructive testing device provided by an embodiment of the present disclosure;
FIG. 2 shows an infrared thermal vibration intensity spectrum of a submicron-sized foreign matter nondestructive testing device provided by an embodiment of the present disclosure for detecting the presence or absence of a foreign matter;
fig. 3 shows a flowchart of a submicron-sized foreign matter nondestructive testing method provided by an embodiment of the present disclosure.
The reference sign of the figure shows 1, the mobile carrier;
2. The device comprises a middle infrared laser, 111, a reflector, 101, a beam splitter, 102, a beam combiner, 103, a half-wave plate, 104 and a polarizer;
3. The laser vibration meter, 31, helium-neon laser, 32, beam splitter, 33, beam combiner, 34, photoelectric detector, 35, acousto-optic modulator;
4. A signal processing module; 41, a lock-in amplifier 42, a processor;
5. photosensitive coupling component and 51, focusing lens.
Detailed Description
In order to make the objects, features and advantages of the present disclosure more comprehensible, the technical solutions in the embodiments of the present disclosure will be clearly described in conjunction with the accompanying drawings in the embodiments of the present disclosure, and it is apparent that the described embodiments are only some embodiments of the present disclosure, but not all embodiments. Based on the embodiments in this disclosure, all other embodiments that a person skilled in the art would obtain without making any inventive effort are within the scope of protection of this disclosure.
Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.
Referring to fig. 1, an embodiment of the disclosure provides a submicron-sized foreign matter nondestructive testing device, which comprises a movable stage 1, a middle infrared laser 2, a laser vibration meter 3 and a signal processing module 4, wherein the movable stage 1 can move a sample piece to be tested along a plurality of different directions, the middle infrared laser 2 is used for emitting middle infrared lasers with different wavelengths to the sample piece to be tested, the laser vibration meter 3 comprises a beam splitter 32, a beam combiner 33 and a photoelectric detector 34 which are sequentially arranged in a self light path, and the signal processing module 4 is electrically connected with the laser vibration meter 3 and is used for receiving and processing measurement signals of the laser vibration meter 3;
the beam splitter 32 can split the laser emitted by the laser vibration meter 3 into detection laser and reference laser, and the detection laser can be reflected, refracted or scattered back to the laser vibration meter 3 after being irradiated on the sample to be measured, the beam combiner 33 is used for combining the reference laser and the reflected, refracted or scattered back detection laser, and the photoelectric detector 34 is used for detecting the interference frequency difference of the combined laser and converting the interference frequency difference into an electric signal of vibration of the sample to be measured.
In an embodiment, the mid-infrared laser 2 can irradiate mid-infrared laser to a sample to be measured through a first optical path, a first dichroic mirror 21, a second dichroic mirror 22 and a reflecting objective 23 are sequentially arranged in the first optical path at intervals along the irradiation direction, the mid-infrared laser can respectively penetrate through the first dichroic mirror 21 and the second dichroic mirror 22, the detection laser can be reflected to the sample to be measured through the second dichroic mirror 22 in a reversing manner or reflected back to the laser vibration meter 3 in a reversing manner, and the reflecting objective 23 is used for focusing the mid-infrared laser and the detection laser to the surface of the sample to be measured.
In one embodiment, the sample piece to be tested can partially reflect the mid-infrared laser light back to the first dichroic mirror 21 along the first light path, the first dichroic mirror 21 can reflect the reflected mid-infrared laser light to the focusing lens 51, and the focusing lens 51 is used for focusing the mid-infrared laser light reflected by the first dichroic mirror 21 on the photosensitive coupling assembly 5.
Dichroic mirrors, also known as dichroic mirrors, are capable of almost completely transmitting light of a certain wavelength, while almost completely reflecting light of other wavelengths.
In one embodiment, the laser vibration meter 3 further includes a helium-neon laser 31 and an acousto-optic modulator 35, the helium-neon laser 31 is used for emitting laser light toward the beam splitter 32, and the laser light is the detection laser light and the reference laser light through the beam splitter 32, and the reference laser light is irradiated to the beam combiner 33 after passing through the acousto-optic modulator 35.
In one embodiment, the signal processing module 4 includes a lock-in amplifier 41 and a processor 42, where the lock-in amplifier 41 is electrically connected to the photodetector 34 and is used for locking the signal vibration measured by the photodetector 34, and the processor 42 is electrically connected to the lock-in amplifier 41 and is capable of drawing a vibration intensity image according to the locking data of the lock-in amplifier 41.
In an embodiment, the processor 42 is further electrically connected to the mid-infrared laser 2, and is capable of controlling the mid-infrared laser 2 to output a plurality of mid-infrared lasers with equidistant wavelengths one by one.
In an embodiment, the processor 42 is further electrically connected to the mobile carrier 1, and can regulate the mobile carrier 1 to perform the scanning movement along the preset track path and the preset speed.
The submicron-level foreign matter nondestructive detection device can be particularly but not exclusively applied to surface submicron-level foreign matters of micro-nano devices, precise instruments, wafer silicon wafers and the like for rapid nondestructive detection and evaluation analysis, does not have any destructive property on a sample to be detected in the detection process, and does not need any additional pre-detection processing such as cutting, extraction, surface treatment and the like on the object to be detected.
Specifically, the detailed description of the use process is given by taking the detection of micro-nano foreign matters on the surface of a silicon wafer, a silicon carbide crystal wafer and the like with submicron photoresist foreign matters as an example.
Before a silicon wafer and a silicon carbide crystal sheet wait for detecting a sample to be detected, the sample to be detected is firstly prepared, the sample to be detected is firstly fixedly placed in a movable carrying platform 1, the movable carrying platform 1 can be specifically arranged to be a three-axis precise electric control displacement platform, the sample to be detected is moved to the position right below a focusing lens 51 by controlling the movable carrying platform 1 to precisely move along an X axis and a Y axis, and then the movable carrying platform 1 is controlled to slowly move along a Z axis to lift the sample to be detected until the sample to be detected is positioned at a focus of the focusing lens 51, namely, the surface of the sample to be detected can be clearly imaged through a camera.
Then, the laser vibrometer 3 is turned on and the detection laser emitted by the laser vibrometer 3 is focused on the surface of the sample to be measured, and the optimal position where the detection laser is just focused on the surface of the sample to be measured is found according to the intensity of the laser energy reflected back to the laser vibrometer 3 by the second dichroic mirror 22 in a direction-changing manner. Then, on the basis of an optical imaging picture, the size and the boundary of an area to be detected on the surface of the sample to be detected are selected and are imported into a control program of the mobile carrier 1 through the signal processing module 4, a path for mobile scanning filling of the mobile carrier 1 is generated, and the actual scanning speed of the mobile carrier 1 is set to be particularly 0.1mm/s-100 mm/s.
Then, the mid-infrared laser 2 is turned on and the mid-infrared laser 2 is made to pulse the mid-infrared laser at a certain repetition frequency, which may be specifically between 10kHz and 1000kHz, and the mid-infrared laser is a broad-spectrum laser light source, the wavelength range may be between 0.8m and 10m, and the output power at a single wavelength is typically between 3mW and 300 mW. The middle infrared laser is focused on the same position as the focus of the detection laser by the focusing lens 51, then a plurality of equidistant wavelengths are selected from the infrared spectrum range of the middle infrared laser and are output one by one, under each wavelength, the mobile carrier 1 operates detection tasks one by one, the specific detection process is that the mobile carrier 1 scans the whole detection area point by point along the preset path and speed, in the scanning process, the signals reflected by the detection laser in the laser vibrometer 3 interfere with the reference laser, the accurate measurement of the vibration displacement and speed of the sample in the area of the point can be realized based on the laser vibration measuring function of Doppler effect, the measuring precision can reach sub picometers, and the vibration data of each point in the whole detection area can be obtained after each detection task is finished.
And the data of the laser vibration meter 3 is led into the phase-locked amplifier 41, the phase-locked amplifier 41 performs phase locking on the signal according to the light source frequency of the mid-infrared laser, so as to obtain the vibration intensity signal of each detection point under the frequency, the signal processing module 4 can draw and obtain the image of the vibration intensity in the whole detection area through point-by-point scanning and splicing, when the detection laser irradiates on the surface of the sample to be detected, the photo-thermal vibration intensity spectrum is the a state in fig. 2 when no foreign matter exists, the photo-thermal vibration intensity spectrum is the b state in fig. 2 when the foreign matter exists, and the intensities in the photo-thermal intensity spectrum are different when the foreign matter sizes are different.
Because the foreign matter components are unclear, in the middle infrared lasers with a plurality of different wavelengths, once the foreign matter material absorbs the middle infrared lasers with a certain wavelength, the foreign matter material can generate obvious thermal vibration under the photo-thermal effect after absorbing the middle infrared lasers, and the frequency of the thermal vibration is the same as that of the middle infrared lasers, so that if a region with obviously enhanced vibration intensity appears in an image of an operation detection task, the region is provided with foreign matters, and the foreign matters obviously absorb the middle infrared lasers, thereby forming the thermal vibration. The infrared absorption wavelength of the foreign material can be determined from the scanned image at each of the mid-infrared laser wavelengths, so that the wavelength of the mid-infrared laser is selected in the subsequent detection process. Finally, the middle infrared laser is adjusted to be the selected wavelength, the detection area on the sample is continuously selected, and two modes of random selective detection and whole detection can be selected to carry out comprehensive detection of the foreign matters.
The submicron-sized foreign matter nondestructive inspection device can be applied to the detection and analysis of the foreign matter component, and the movement of the movable stage 1 is controlled in the above-described area where the presence of the foreign matter is determined, the foreign matter is moved to the focal point of the detection laser, and the position of the movable stage 1 is fixed to measure the point. Then, the beam interval and interval time of the mid-infrared laser are set to gradually scan out, the energy of the mid-infrared laser is kept constant under a single wavelength, and the signal intensity spectrum under the mid-infrared laser wavelength scanning is recorded by using the lock-in amplifier 41, so that the wavelength of the vibration peak position of the foreign material can be obtained. Finally, the composition of the foreign material is analyzed and judged according to the positions of infrared absorption fingerprint peaks of common chemical bonds.
And before the sample to be detected is detected, a dielectric film which does not consume the surface of the sample can be arranged on the surface of the sample to be detected, so that the detection signal is enhanced.
In summary, the submicron-level foreign matter nondestructive detection device provided by the embodiment of the disclosure has no destructiveness to the sample to be detected in the whole detection process, does not need to perform any additional pre-detection processing such as cutting and extraction on the sample to be detected, can be suitable for online detection operation of a sample production line to be detected, can detect the minimum size of the foreign matter to reach 2nm, and has the detection efficiency of 10 minutes/1 mm x 1mm, so that the rapid detection and evaluation analysis of the foreign matter on the surface of a large-size device can be realized.
In addition, as shown in fig. 3, the embodiment of the disclosure further provides a nondestructive testing method for a submicron-sized foreign matter, which can be applied to the nondestructive testing device for a submicron-sized foreign matter, and includes the following steps:
The first step, fixedly placing a sample piece to be detected on a mobile carrier 1, and adjusting the mobile carrier 1 to enable the sample to be detected to be accurately positioned in a detection focus area;
The second step, the laser vibration meter 3 emits detection laser to the sample piece to be detected, and the signal processing module 4 selects the boundary of the area to be detected in the sample to be detected based on the optical imaging picture of the laser vibration meter 3 and generates a mobile scanning filling path of the mobile carrier 1;
and thirdly, transmitting middle infrared laser with repetition frequency to the sample to be tested through the middle infrared laser 2, selecting a plurality of equidistant wavelengths in the spectrum range of the middle infrared laser to be output one by one, and operating the detection task one by the laser vibrometer 3 under each wavelength, and drawing a vibration intensity distribution image by the signal processing module 4 according to the plurality of wavelengths of the middle infrared laser.
In one embodiment, the submicron order foreign matter nondestructive testing method further comprises:
A preliminary step before the first step of providing a dielectric film to the surface to be measured of the sample to be measured to enhance the response sensitivity to the detection laser;
And in the follow-up detection step after the third step, the wavelength of the middle infrared laser emitted by the selected middle infrared laser 2 is adjusted according to the wave crest in the vibration intensity distribution image, and the random selective detection or the whole surface detection is carried out on other positions of the sample piece to be detected.
In one embodiment, the submicron order foreign matter nondestructive testing method further comprises:
And a foreign matter component analysis step, setting a scanning output period of the middle infrared laser 2, recording a signal intensity spectrum under the middle infrared laser by a lock-in amplifier 41 to obtain the wavelength of the vibration peak position of the foreign matter material, and analyzing and judging the foreign matter material component according to the position of the infrared absorption fingerprint peak of the common chemical bond.
The submicron-level foreign matter nondestructive detection method provided by the embodiment of the disclosure can be suitable for the submicron-level foreign matter nondestructive detection device, can also realize that the sample to be detected does not have any destructiveness in the whole detection process, does not need to carry out any additional pre-detection processing such as cutting and extraction on the sample to be detected, and can also be suitable for online detection operation of a sample production line to be detected and rapid detection of the foreign matter on the surface of a large-size device.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present disclosure, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
The foregoing is merely a specific embodiment of the disclosure, but the protection scope of the disclosure is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the disclosure, and it should be covered in the protection scope of the disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.