Second harmonic characterization and optimization system

Abstract

The invention provides a second harmonic characterization and optimization system, which comprises an incident light path system, an emergent light path system and an annealing light path system, and is characterized in that the incident light path system is used for enabling a light beam emitted by an incident laser source to enter a tested sample to generate second harmonics; a signal reflected by the second harmonic waves passes through the emergent light path system and then enters a spectrograph to analyze a result; and the annealing light path system is used for annealing a tested sample. According to the second harmonic characterization and optimization system, the annealing light path system capable of achieving in-situ laser annealing is arranged, accurate characterization of interface signals is achieved, meanwhile, accurate annealing is conducted on the same position, the annealing effect can be fed back in real time, time and material losses of the steps of electrode introduction and the like are reduced, and the service life of the second harmonic characterization and optimization system is prolonged. And meanwhile, the laser annealing effect can be subjected to secondary harmonic measurement and real-time feedback through integrated arrangement of laser secondary harmonic and laser annealing, and the result of increasing the yield is achieved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor testing technology, and in particular to a second harmonic characterization and optimization system. Background Technology

[0002] As semiconductor devices evolve towards nanoscale and three-dimensional structures, the density of interface states (Dit) has an increasingly significant impact on device performance. Interface states, acting as carrier recombination centers, can lead to increased leakage current, decreased mobility, and reliability degradation. This is particularly true in advanced logic chips, memory devices, and novel two-dimensional material heterojunctions, where accurate characterization of interface defects has become a bottleneck for performance optimization. Traditional detection methods, such as capacitance-voltage (CV) testing and deep-level transient spectroscopy (DLTS), rely on electrical contact or destructive sample preparation, making non-invasive, in-situ monitoring difficult and lacking sensitivity for ultrathin interfaces or complex heterostructures. Therefore, a high-precision, non-contact, in-situ detection technology is urgently needed to analyze the dynamic evolution of interface states in real time, providing direct evidence for process optimization.

[0003] To reduce interface state density, laser annealing technology has become a cutting-edge solution for repairing interface defects due to its advantages such as localized heating and controllable thermal budget. However, the control of annealing parameters (such as energy density and pulse width) in existing processes largely relies on empirical trial and error, lacking real-time feedback on the interface state elimination effect, which can easily lead to over-annealing (damaging the material) or under-annealing (defect residue). In addition, traditional annealing requires offline electrical testing to evaluate the effect, which is a cumbersome process and difficult to achieve closed-loop control. Summary of the Invention

[0004] The purpose of this invention is to provide a second harmonic characterization and optimization system to solve the problems of insufficient accuracy in interface state density detection, single and inefficient control methods in the prior art.

[0005] This invention provides a second harmonic characterization and optimization system, including an incident optical path system, an outgoing optical path system, and an annealing optical path system. The incident optical path system is used to incident a light beam emitted from an incident laser source onto the sample under test to generate a second harmonic. The signal reflected by the second harmonic passes through the outgoing optical path system and is then incident into a spectrometer for analysis. The annealing optical path system performs annealing treatment on the sample under test based on the feedback signal from the spectrometer. The annealing optical path system includes an annealing laser source, a first polarizer, a beam shaper, a laser galvanometer, and a telecentric lens. The beam generated by the annealing laser source is parallelized by the first polarizer and enters the beam shaper to be shaped from a Gaussian beam to a flat-top beam. The flat-top beam is reflected by the laser galvanometer and then incident perpendicularly onto the sample under test. Finally, it is focused onto the sample under test by the telecentric lens.

[0006] According to the second harmonic characterization and optimization system provided by the present invention, the incident optical path system includes a first half-wave plate, a second polarizer, a first polarizer and a first lens arranged sequentially between the incident laser source and the sample under test. The beam emitted from the incident laser source changes its power after passing through the first half-wave plate and the second polarizer, then the polarization direction is adjusted by the first polarizer, and then the beam is focused on the sample under test by the first lens to generate a second harmonic.

[0007] According to the second harmonic characterization and optimization system provided by the present invention, the incident laser source is a femtosecond laser; the annealing laser source is a picosecond laser; and both the first polarizer and the second polarizer are Gran-Thompson polarizers.

[0008] The second harmonic characterization and optimization system provided by the present invention further includes a control system, which is connected to the femtosecond laser, the picosecond laser and the spectrometer respectively.

[0009] According to the second harmonic characterization and optimization system provided by the present invention, a first power meter is further provided between the first polarizer and the first lens. The first power meter is used to measure the laser power incident on the sample under test.

[0010] According to the second harmonic characterization and optimization system provided by the present invention, the outgoing optical path system includes a second lens, a second half-wave plate and a filter plate arranged sequentially between the sample under test and the spectrometer. The signal reflected by the second harmonic is collimated by the second lens, passes through the second half-wave plate, and is then filtered by the filter plate to extract the fundamental frequency light before being incident into the spectrometer for analysis.

[0011] The second harmonic characterization and optimization system provided by the present invention further includes a single-photon counter that is communicatively connected to the spectrometer.

[0012] According to the second harmonic characterization and optimization system provided by the present invention, the annealing laser source, the first polarizer, the beam shaper and the laser galvanometer are arranged in sequence in the horizontal direction above the sample under test, and the laser galvanometer is located directly above the sample under test, and the telecentric lens is located directly below the laser galvanometer.

[0013] According to the second harmonic characterization and optimization system provided by the present invention, a second power meter is further provided between the beam shaper and the laser galvanometer, and the second power meter is used to measure the annealing power.

[0014] The second harmonic characterization and optimization system provided by the present invention further includes a displacement platform, which is used to support the sample under test for position adjustment.

[0015] The second harmonic characterization and optimization system provided by this invention integrates an incident optical path system, an exit optical path system, and an annealing optical path system. The incident optical path system is used to direct the light beam emitted from the incident laser source onto the sample under test to generate a second harmonic. The signal reflected by the second harmonic passes through the exit optical path system and is then sent to a spectrometer for analysis. The annealing optical path system performs annealing treatment on the sample under test based on the feedback signal from the spectrometer. In other words, by setting up an annealing optical path system that can perform in-situ laser annealing, this invention achieves accurate characterization of interface signals while performing precise annealing at the same location, and can provide real-time feedback on the annealing effect. This reduces the time and material loss associated with steps such as introducing electrodes. At the same time, the integrated setup of laser second harmonic and laser annealing allows for further second harmonic measurement of the laser annealing effect and real-time feedback, thereby increasing the yield. This effectively solves the problems of insufficient accuracy in interface state density detection, single control method, and low efficiency in existing technologies.

[0016] The second harmonic characterization and optimization system provided by this invention utilizes the high sensitivity and non-destructive characteristics of SHG technology to achieve in-situ, real-time detection of the interface state density of semiconductor devices. Combined with laser annealing technology, it can precisely control the interface region, effectively reduce the interface state density, and improve interface characteristics.

[0017] The second harmonic characterization and optimization system provided by this invention integrates second harmonic generation (SHG), a nonlinear optical detection method sensitive to interface symmetry, with in-situ laser annealing. This overcomes the bottleneck of the disconnect between process monitoring and repair, quantifying interface state changes in real time through SHG signals and dynamically optimizing annealing parameters. This achieves integrated "detection-repair-verification" at the atomic scale, providing a disruptive solution for high-precision interface engineering. Therefore, this invention provides an efficient, accurate, and widely applicable interface state density detection and control scheme for semiconductor manufacturing, offering technical support for improving the performance and reliability of semiconductor devices. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the second harmonic characterization and optimization system of the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. Incident laser source; 2. First half-wave plate; 3. Second polarizer; 4. First polarizer; 5. First power meter; 6. First lens; 7. Second lens; 8. Second half-wave plate; 9. Filter; 10. Spectrometer; 11. Single-photon counter; 12. Annealed laser source; 13. First polarizer; 14. Beam shaper; 15. Second power meter; 16. Laser galvanometer; 17. Telecentric lens; 18. Control system; 19. Sample under test; 20. Displacement platform. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] like Figure 1As shown, the second harmonic characterization and optimization system of this invention includes an incident optical path system, an exit optical path system, and an annealing optical path system. The incident optical path system is used to direct the light beam emitted from the incident laser source 1 onto the sample 19 under test to generate a second harmonic. The signal reflected from the second harmonic passes through the exit optical path system and is then sent to the spectrometer 10 for analysis. The annealing optical path system performs annealing treatment on the sample 19 under test based on the feedback signal from the spectrometer 10. The laser in the annealing optical path system acts on the interface of the sample 19 under test (i.e., semiconductor material), and the interface quality and interface state are controlled and optimized through laser annealing. That is, if the sample interface state obtained by analyzing the second harmonic is not ideal, a feedback signal can be sent to the annealing optical path system to perform annealing treatment on the sample 19 under test. After annealing, its interface state can be measured again, and it can be analyzed whether further annealing is needed.

[0025] The annealing optical path system includes an annealing laser source 12, a first polarizer 13, a beam shaper 14, a laser galvanometer 16, and a telecentric lens 17. The beam generated by the annealing laser source 12 is parallelized by the first polarizer 13 and then enters the beam shaper 14 to be shaped from a Gaussian beam to a flat-top beam. The flat-top beam is reflected by the laser galvanometer 16 and then incident perpendicularly onto the sample 19 under test. Finally, it is focused onto the sample 19 under test by the telecentric lens 17. The purpose of setting up the beam shaper 14 is to ensure that the energy density of the flat-top beam is almost uniform within the beam region, resulting in a flat and uniform energy distribution and a more consistent interface optimization effect. The telecentric lens 17 can adjust the focal position to focus onto the sample 19 under test, thereby improving the annealing rate.

[0026] Therefore, the second harmonic characterization and optimization system of this invention, by setting up an annealing optical path system that can perform in-situ laser annealing, can achieve accurate characterization of interface signals while performing precise annealing at the same location, and can provide real-time feedback of the annealing effect, reducing the time and material loss of steps such as introducing electrodes. At the same time, the integrated setting of laser second harmonic and laser annealing can perform second harmonic measurement on the laser annealing effect and provide real-time feedback, thereby increasing the yield. It effectively solves the problems of insufficient accuracy of interface state density detection, single control method and low efficiency in the prior art.

[0027] In some embodiments of the present invention, the incident optical path system includes a first half-wave plate 2, a second polarizer 3, a first polarizer 4, and a first lens 6 sequentially disposed between the incident laser source 1 and the sample 19 under test. The beam emitted from the incident laser source 1 changes its power after passing through the first half-wave plate 2 and the second polarizer 3, then the polarization direction is adjusted by the first polarizer 4, and then the beam is focused on the sample 19 under test by the first lens 6 to generate a second harmonic.

[0028] In this design, the incident laser source 1 is a femtosecond laser, and the second polarizer 3 is a Glan-Thompson polarizer. By exciting a second harmonic generation (SHG) signal with a femtosecond laser, interface state density information can be obtained in real time without the need for electrode fabrication or sample destruction. Moreover, the ultrafast pulse and ultra-fine processing capabilities of the femtosecond laser, combined with the high sensitivity of SHG to interface symmetry breaking, enable the repair of micron-level local defects.

[0029] Among them, a first power meter 5 is provided between the first polarizer 4 and the first lens 6. The first power meter 5 is used to measure the laser power incident on the sample 19 under test.

[0030] In some embodiments of the present invention, the outgoing optical path system includes a second lens 7, a second half-wave plate 8 and a filter 9 arranged sequentially between the sample 19 to be tested and the spectrometer 10. The signal reflected by the second harmonic is collimated by the second lens 7, passes through the second half-wave plate 8, and is then filtered out by the filter 9 to produce the fundamental frequency light before entering the spectrometer 10 for analysis.

[0031] Furthermore, it also includes a single-photon counter 11 that is communicatively connected to the spectrometer 10.

[0032] Specifically, the annealing laser source 12, the first polarizer 13, the beam shaper 14, and the laser galvanometer 16 are arranged in sequence along the horizontal direction above the sample 19 to be tested, with the laser galvanometer 16 located directly above the sample 19 to be tested and the telecentric lens 17 located directly below the laser galvanometer 16.

[0033] Among them, the annealing laser source 12 is a picosecond laser, and the first polarizer 13 is a Gran-Thompson polarizer.

[0034] A second power meter 15 is provided between the beam shaper 14 and the laser galvanometer 16. The second power meter 15 is used to measure the annealing power.

[0035] In some embodiments of the present invention, the second harmonic characterization and optimization system further includes a control system 18, which is connected to the femtosecond laser, the picosecond laser and the spectrometer 10 respectively. That is, the control system 18 can control the operation of the femtosecond laser, and the control system 18 can receive the feedback signal from the spectrometer 10 and then adjust the picosecond laser according to the feedback signal.

[0036] Therefore, the second harmonic characterization and optimization system of this invention, combined with time-dependent SHG and automatic adjustment of laser annealing parameters, can optimize interface quality, reduce interface state density and improve wafer interface state uniformity. By monitoring the interface state density of the annealing region in real time, it reduces repetitive experiments in traditional processes and reduces energy consumption and material loss.

[0037] In some embodiments of the present invention, the second harmonic characterization and optimization system further includes a displacement platform 20, which is used to support the sample 19 under test for position adjustment, and the displacement platform 20 can be adjusted along the x-axis, y-axis, z-axis, and θ-axis. The displacement platform 20 provides a travel range of more than 6 inches along the x-axis and y-axis, which can meet the annealing requirements of most wafers, and the z-axis can be adjusted to focus the position, making the annealing position more accurate.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A second harmonic characterization and optimization system, characterized in that, It includes an incident optical path system, an exit optical path system, and an annealing optical path system. The incident optical path system is used to direct the light beam emitted from the incident laser source onto the sample to generate a second harmonic wave. The signal reflected by the second harmonic wave passes through the exit optical path system and is then sent into the spectrometer for analysis. The annealing optical path system performs annealing treatment on the sample based on the feedback signal from the spectrometer. The annealing optical path system includes an annealing laser source, a first polarizer, a beam shaper, a laser galvanometer, and a telecentric lens. The beam generated by the annealing laser source is parallelized by the first polarizer and enters the beam shaper to be shaped from a Gaussian beam to a flat-top beam. The flat-top beam is reflected by the laser galvanometer and then incident perpendicularly onto the sample under test. Finally, it is focused onto the sample under test by the telecentric lens.

2. The second harmonic characterization and optimization system according to claim 1, characterized in that, The incident optical path system includes a first half-wave plate, a second polarizer, a first polarizer, and a first lens, which are sequentially arranged between the incident laser source and the sample under test. The beam emitted from the incident laser source changes its power after passing through the first half-wave plate and the second polarizer, then its polarization direction is adjusted by the first polarizer, and finally it is focused on the sample under test by the first lens to generate a second harmonic.

3. The second harmonic characterization and optimization system according to claim 2, characterized in that, The incident laser source is a femtosecond laser; the annealing laser source is a picosecond laser; both the first polarizer and the second polarizer are Gran-Thompson polarizers.

4. The second harmonic characterization and optimization system according to claim 3, characterized in that, It also includes a control system, which is connected to the femtosecond laser, the picosecond laser and the spectrometer respectively.

5. The second harmonic characterization and optimization system according to claim 2, characterized in that, A first power meter is also provided between the first polarizer and the first lens. The first power meter is used to measure the laser power incident on the sample under test.

6. The second harmonic characterization and optimization system according to claim 1, characterized in that, The outgoing optical path system includes a second lens, a second half-wave plate, and a filter plate arranged sequentially between the sample under test and the spectrometer. The signal reflected by the second harmonic is collimated by the second lens, passes through the second half-wave plate, and is then filtered by the filter plate to extract the fundamental frequency light before being incident into the spectrometer for analysis.

7. The second harmonic characterization and optimization system according to claim 6, characterized in that, It also includes a single-photon counter that is communicatively connected to the spectrometer.

8. The second harmonic characterization and optimization system according to claim 1, characterized in that, The annealing laser source, the first polarizer, the beam shaper, and the laser galvanometer are arranged in sequence along the horizontal direction above the sample under test, with the laser galvanometer located directly above the sample under test and the telecentric lens located directly below the laser galvanometer.

9. The second harmonic characterization and optimization system according to claim 8, characterized in that, A second power meter is also provided between the beam shaper and the laser galvanometer, which is used to measure the annealing power.

10. The second harmonic characterization and optimization system according to claim 1, characterized in that, It also includes a displacement platform, which is used to support the sample under test for position adjustment.

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