Second harmonic characterization and optimization system
By integrating a second harmonic characterization and optimization system, second harmonic signals are generated using femtosecond and picosecond lasers, and laser annealing is performed in combination with vacuum cavity and spectrometer feedback. This solves the problems of insufficient accuracy and contamination in second harmonic characterization in semiconductor testing, and achieves efficient and accurate interface defect detection and optimization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-28
- Publication Date
- 2026-04-03
AI Technical Summary
Existing second harmonic characterization techniques are prone to causing environmental pollution in semiconductor testing, and the signals are weak and the accuracy is insufficient, making it difficult to achieve efficient and accurate interface defect detection and optimization.
An integrated second harmonic characterization and optimization system is adopted, including a vacuum cavity, an incident optical path system, an exit optical path system, and an annealing optical path system. Second harmonic signals are generated using femtosecond and picosecond lasers, and annealing is performed through feedback from a spectrometer. Combined with a vacuum cavity with adjustable atmosphere, in-situ laser annealing and real-time feedback are achieved.
It improves the accuracy and signal strength of second harmonic characterization, reduces environmental pollution, enables efficient and accurate detection and optimization of semiconductor interface defects, and enhances device performance and reliability.
Smart Images
Figure CN121783924A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor detection technology, and in particular to a second harmonic characterization and optimization system for interface state density characterization and interface state optimization. Background Technology
[0002] As the integration level in the semiconductor field increases and device feature sizes continue to shrink, the defects generated at the wafer interface are becoming increasingly significant. To detect interface defects and improve device reliability, various wafer defect characterization techniques have been developed. For example, X-ray diffraction (XRD) can analyze polymorphic dislocations based on diffraction patterns, but obtaining wafer-level defects is time-consuming; beam-induced current (OBIC) can detect the location of defects, but it depends on specific device structures; transmission electron microscopy (TEM) can acquire high-resolution defect images, but sample preparation is destructive.
[0003] Second harmonic generation (SHG) is a characterization technique developed in recent years based on second-order nonlinear optics generated by high-intensity laser irradiation of materials. Among numerous characterization methods, SHG has demonstrated its ability to characterize the electric field and structural properties of material interfaces due to its non-destructive testing, high stability, and simple operation. However, the application prospects and demands of existing SHG-based characterization techniques for semiconductors face challenges. These include potential contamination of semiconductors in actual characterization environments, and signal attenuation due to environmental scattering and absorption of the fundamental frequency by certain gases, ultimately leading to a decrease in the accuracy of SHG characterization of semiconductor interface defects. Summary of the Invention
[0004] The purpose of this invention is to provide a second harmonic characterization and optimization system that can protect the semiconductor under test from environmental pollution, ensure convection and temperature stability, and improve the intensity of the generated second harmonic signal, thereby improving the accuracy of second harmonic characterization.
[0005] This invention provides a second harmonic characterization and optimization system, comprising a vacuum cavity, an incident optical path system, an outgoing optical path system, and an annealing optical path system. The sample to be tested is placed inside the vacuum cavity. The incident optical path system is used to direct a laser beam emitted from an incident laser source onto the sample to generate a second harmonic. The signal reflected by the second harmonic passes through the outgoing optical path system and is then sent to a spectrometer for analysis. The annealing optical path system performs annealing treatment on the sample based on the feedback signal from the spectrometer. The vacuum cavity is used to adjust the vacuum level or fill the atmosphere. 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] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] According to the second harmonic characterization and optimization system provided by the present invention, the annealing optical path system further includes a beam splitter and a second power meter. The beam splitter is disposed between the beam shaper and the laser galvanometer, and the second power meter is used to measure the annealing power.
[0013] 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.
[0014] 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.
[0015] The second harmonic characterization and optimization system provided by this invention integrates a vacuum cavity, an incident optical path system, an exit optical path system, and an annealing optical path system. The sample to be tested is placed inside the vacuum cavity. The incident optical path system directs the laser beam emitted from the incident laser source onto the sample to generate a second harmonic. The reflected signal from 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 based on the feedback signal from the spectrometer. The vacuum cavity is used to adjust the vacuum level or provide the necessary atmosphere for laser annealing. In other words, this invention, by setting up an annealing optical path system capable of in-situ laser annealing, achieves accurate characterization of interface signals while simultaneously performing precise annealing at the same location, and can provide real-time feedback on the annealing effect, reducing... By eliminating the time and material loss associated with introducing electrodes, the integrated setup of laser second harmonic generation and laser annealing allows for further second harmonic measurement of the laser annealing effect, providing real-time feedback and increasing yield. This effectively solves the problems of insufficient accuracy in interface state density detection, limited control methods, and low efficiency in existing technologies. Simultaneously, utilizing a vacuum chamber with an adjustable atmosphere for second harmonic defect characterization allows for more effective sample characterization in a vacuum environment. This protects the semiconductor under test from environmental contamination, ensures convection and temperature stability, and enhances the intensity of the generated second harmonic signal, thereby improving the accuracy of second harmonic characterization. Furthermore, the atmosphere for laser annealing can be adjusted, enabling real-time and efficient annealing of interfaces with unsatisfactory measurement results, reducing measurement and experimental steps.
[0016] 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
[0017] 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.
[0018] Figure 1 This is a schematic diagram of the structure of the second harmonic characterization and optimization system of the present invention.
[0019] 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. Beam splitter; 19. Sample under test; 20. Displacement platform; 21. Vacuum cavity. Detailed Implementation
[0020] 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.
[0021] 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.
[0022] 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.
[0023] like Figure 1 As shown, the second harmonic characterization and optimization system of this invention includes a vacuum cavity 21, an incident optical path system, an exit optical path system, and an annealing optical path system. The sample 19 to be tested is placed inside the vacuum cavity 21. The incident optical path system directs the light beam emitted from the incident laser source 1 onto the sample 19 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 based on the feedback signal from the spectrometer 10. The vacuum cavity 21 is used to adjust the vacuum level or provide the atmosphere required for laser annealing. The laser in the annealing optical path system acts on the interface of the sample 19 (i.e., the semiconductor material), controlling the interface quality and optimizing the interface state 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. After annealing, its interface state can be measured again to analyze whether further annealing is needed.
[0024] 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.
[0025] 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.
[0026] Meanwhile, the second harmonic characterization and optimization system of this invention utilizes a vacuum cavity 21 with an adjustable atmosphere to characterize defects in the second harmonic. This allows for more effective characterization of samples in a vacuum environment, protecting the semiconductor under test from environmental contamination and ensuring convection and temperature stability. It also increases the intensity of the generated second harmonic signal, thereby improving the accuracy of the second harmonic characterization. Furthermore, it allows for atmosphere adjustment for laser annealing, enabling real-time and efficient annealing of interfaces with unsatisfactory measurement results, reducing measurement and experimental steps.
[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] The annealing optical path system also includes a beam splitter 18 and a second power meter 15. The beam splitter 18 is disposed between the beam shaper 14 and the laser galvanometer 16, and 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, which is connected to the femtosecond laser, the picosecond laser and the spectrometer 10 respectively. That is, the control system can control the femtosecond laser to work, and the control system can receive feedback signals from the spectrometer 10 and then adjust the picosecond laser according to the feedback signals.
[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 10. This displacement platform 20 is used to support the sample 19 under test for position adjustment, and it can be adjusted along the x-axis, y-axis, z-axis, and θ-axis. Specifically, the displacement platform 20 provides a travel range of over 6 inches along the x and y axes, which can meet the annealing requirements of most wafers. 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, The system includes a vacuum chamber, an incident optical path system, an exit optical path system, and an annealing optical path system. The sample to be tested is placed inside the vacuum chamber. 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 to the spectrometer for analysis. The annealing optical path system performs annealing treatment on the sample based on the feedback signal from the spectrometer. The vacuum chamber is used to adjust the vacuum level or fill the atmosphere. 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 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.
5. 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.
6. The second harmonic characterization and optimization system according to claim 5, characterized in that, It also includes a single-photon counter that is communicatively connected to the spectrometer.
7. 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.
8. The second harmonic characterization and optimization system according to claim 7, characterized in that, The annealing optical path system also includes a beam splitter and a second power meter. The beam splitter is disposed between the beam shaper and the laser galvanometer, and the second power meter is used to measure the annealing power.
9. 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.
10. 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.