Extra-cavity frequency doubling continuous deep ultraviolet laser device and system and semiconductor detection system

Abstract

The invention provides an extra-cavity frequency doubling continuous deep ultraviolet laser device, a laser system and a semiconductor detection system. The device comprises an infrared laser module, a green laser module and a deep ultraviolet laser module. The infrared laser module is used for generating target continuous infrared laser; the green laser module comprises an infrared reflector assembly and a first conversion assembly, the infrared reflector assembly is used for converting a transmission light path of the target continuous infrared laser from a first red light path to a second red light path, and the first conversion assembly is used for performing multi-pass second harmonic conversion on the target continuous infrared laser to obtain target continuous green laser. The deep ultraviolet laser module comprises a green light reflector and a second conversion assembly, the green light reflector is used for converting a transmission light path of the target continuous green laser from a first green light path to a second green light path, and the second conversion assembly is used for performing multi-pass fourth harmonic conversion on the target continuous green laser to obtain target continuous deep ultraviolet laser. Therefore, the technical implementation difficulty can be reduced, and the conversion efficiency is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of laser technology, and in particular to a continuous deep ultraviolet laser device, a laser system and a semiconductor detection system. Background Art

[0002] At present, the technology of using continuous deep ultraviolet laser to detect defects in semiconductors (such as wafers) has become the mainstream technology. Specifically, the conversion efficiency of harmonics can be improved based on the resonant cavity technology to achieve higher power output. However, this technical solution is relatively complex, expensive, the system is relatively sensitive, and has high requirements for vibration, temperature and humidity, resulting in harsh transportation and use conditions and high maintenance costs. The conventional continuous optical cavity external single-pass harmonic method cannot achieve the required higher power due to its low conversion efficiency. Therefore, how to reduce the technical difficulty while ensuring the conversion efficiency is a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of this, the purpose of the present disclosure is to provide a continuous deep ultraviolet laser device and a laser system, which can improve the conversion efficiency while reducing the difficulty of technical implementation.

[0004] The present disclosure provides an extracavity frequency-doubled continuous deep ultraviolet laser device, comprising an infrared laser module, a green laser module and a deep ultraviolet laser module; wherein the infrared laser module is used to generate a target continuous infrared laser, the green laser module is used to perform multi-pass second harmonic conversion on the target continuous infrared laser to convert the target continuous infrared laser into a target continuous green laser, and the deep ultraviolet laser module is used to perform multi-pass fourth harmonic conversion on the target continuous green laser to convert the target continuous green laser into a target continuous deep ultraviolet laser; the target continuous deep ultraviolet laser is used to detect semiconductors;

[0005] The green laser module includes an infrared reflector assembly and a first conversion assembly; the infrared reflector assembly is used to convert the transmission optical path of the target continuous infrared laser into a second red light path through a first red light path; the first conversion assembly is used to perform multi-pass second harmonic conversion on the target continuous infrared laser transmitted through the second red light path to obtain the target continuous green laser;

[0006] The deep ultraviolet laser module includes a green light reflector and a second conversion component. The green light reflector is used to convert the transmission optical path of the target continuous green laser from a first green light path to a second green light path; the second conversion component is used to perform multi-pass fourth harmonic conversion on the target continuous green laser transmitted through the second green light path to obtain the target continuous deep ultraviolet laser.

[0007] In a possible implementation manner, when the order of second harmonic conversion is double-pass, the first conversion component includes a first frequency doubling element, a first reflector, a first dichroic mirror, and a first optical power absorber;

[0008] The first frequency doubling element is used to receive the target continuous infrared laser transmitted through the second red light path, and convert part of the target continuous infrared laser into a first continuous green laser, wherein the first continuous green laser and the first remaining continuous infrared laser form a first mixed light;

[0009] The first reflector is disposed at one side of the first frequency doubling element, and is used to reflect the received first mixed light to the first frequency doubling element, so that the first frequency doubling element converts the reflected part of the first residual continuous infrared laser energy into the first continuous green laser to form the target continuous green laser; the transmission optical path of the target continuous green laser avoids the infrared reflector assembly;

[0010] The first dichroic mirror is arranged on a side of the first frequency doubling element away from the first reflector, and is used to transmit the second remaining continuous infrared laser after double-pass conversion by the first frequency doubling element to the first optical power absorber, and reflect the target continuous green laser to the first green light path; the transmission light path of the second remaining continuous infrared laser output from the first frequency doubling element avoids the infrared reflector assembly.

[0011] In a possible implementation, the first conversion component further includes a first phase compensation element, which is disposed between the first frequency doubling element and the first reflector and is used to achieve phase matching between the first residual continuous infrared laser and the first continuous green light.

[0012] In a possible implementation, when the order of the fourth harmonic conversion is double-pass, the second conversion component includes a second frequency doubling element, a second reflector, and a second dichroic mirror;

[0013] The second frequency doubling element is disposed on one side of the green light reflector, and is used to receive the target continuous green laser transmitted through the second green light path, and convert part of the target continuous green laser into a first continuous deep ultraviolet laser, wherein the first continuous deep ultraviolet laser and the first remaining continuous green laser form a second mixed light;

[0014] The second reflector is arranged on a side of the second frequency doubling element away from the green light reflector, and is used to reflect the received second mixed light to the second frequency doubling element, so that the second frequency doubling element converts the reflected part of the first residual continuous green laser energy into the first continuous deep ultraviolet light to form the target continuous deep ultraviolet laser; the transmission optical path of the target continuous deep ultraviolet laser avoids the green light reflector;

[0015] The second dichroic mirror is arranged on a side of the second frequency doubling element away from the second reflector, and is used to transmit the second remaining continuous green laser after double-pass conversion by the second frequency doubling element and reflect the target continuous deep ultraviolet laser; the transmission optical path of the second remaining continuous green laser output from the second frequency doubling element avoids the green light reflector.

[0016] In a possible implementation, the second conversion component further includes a second phase compensation element, and the second phase compensation element is disposed between the second frequency doubling element and the second reflector, and is used to achieve phase matching between the first residual continuous green laser and the first continuous deep ultraviolet laser.

[0017] In a possible implementation, the first reflector is a dichroic concave reflector for reflecting infrared laser and green laser; and / or the first frequency doubling element is a second harmonic nonlinear crystal of a non-critical phase matching type.

[0018] In a possible implementation, the second reflector is a dichroic concave reflector for reflecting green laser and deep ultraviolet laser; and / or the second frequency doubling element is a fourth harmonic nonlinear crystal, and the length of the second frequency doubling element is greater than a preset length.

[0019] In a possible implementation, the infrared reflector assembly includes a first infrared reflector and a second infrared reflector, wherein the first infrared reflector is disposed on the first red light path; and the second infrared reflector is disposed on the second red light path.

[0020] In a possible embodiment, the second conversion component also includes a shaping element, which is arranged on the first green light path and is used to shape the target continuous green laser into an elliptical spot for output, wherein the major axis direction of the elliptical spot corresponds to the phase matching direction of the second frequency doubling element, and the minor axis direction of the elliptical spot corresponds to the non-phase matching direction of the second frequency doubling element.

[0021] In a possible implementation, the infrared laser module includes:

[0022] An infrared laser, used for generating initial continuous infrared laser;

[0023] An infrared light adjustment component is arranged on the initial red light path for transmitting the initial continuous infrared laser, and is used to adjust the power and polarization state of the initial continuous infrared laser to obtain the target continuous infrared laser; the direction of the first red light path for transmitting the target continuous infrared laser is the same as the direction of the initial red light path.

[0024] In a possible implementation, the infrared light adjustment component includes:

[0025] A first light-collecting mirror is arranged on the initial red light path, and is used to reflect part of the initial continuous infrared laser to the first power probe, and output the remaining initial continuous infrared laser;

[0026] The first power sensor is used to detect the power of the initial continuous infrared laser, and to generate a first adjustment instruction when the power of the initial continuous infrared laser exceeds a first preset range; the first adjustment instruction is used to instruct the infrared laser to adjust the power of the initial continuous infrared laser so that the initial continuous infrared laser is within the first preset range;

[0027] A first half-wave plate, arranged on the initial red light path, for changing the polarization direction of the initial continuous infrared laser;

[0028] A polarization beam splitter is arranged on the optical path of the initial red light and is located on the side of the first half-wave plate away from the first light-collecting mirror, and is used to split the remaining initial continuous infrared laser after the polarization direction is changed into a first continuous infrared laser and a second continuous infrared laser with different polarization directions; wherein the optical path direction of the first continuous infrared laser is the same as the optical path direction of the initial continuous infrared laser, and the optical path direction of the second continuous infrared laser is perpendicular to the optical path direction of the initial continuous infrared laser;

[0029] A first focusing lens is arranged on the initial red light path and is located on a side of the polarization beam splitter away from the first half-wave plate, and is used for focusing the first continuous infrared laser into the target continuous infrared laser, and the target continuous infrared laser is incident on the infrared reflector assembly along the first red light path;

[0030] A second light-collecting mirror is arranged in the optical path direction of the second continuous infrared laser, and is used to reflect a part of the second continuous infrared laser to the second power probe, and output the remaining second continuous infrared laser to the third optical power absorber;

[0031] The second power sensor is used to detect the power of the second continuous infrared laser, and the power of the second continuous infrared laser is used to determine whether the power of the first continuous infrared laser exceeds a second preset range;

[0032] When the power of the first continuous infrared laser exceeds the second preset range, a second adjustment instruction is generated, and the second adjustment instruction is used to instruct the half-wave plate to adjust the rotation angle so that the power of the first continuous infrared laser is within the second preset range.

[0033] In a possible implementation, when the number of second harmonic conversions is N passes and the N pass paths are partially collinear, where N is an even number greater than 2, the first conversion component includes M groups of reflection components, a third frequency doubling element, and a third dichroic mirror, where M is half of N;

[0034] The third frequency doubling element is used to receive the target continuous infrared laser transmitted through the second red light path, and perform N-pass conversion on the target continuous infrared laser through the M groups of reflective components to form a target mixed light; the target mixed light includes a target continuous green laser and a target remaining continuous infrared laser;

[0035] The infrared reflector assembly is also used to receive the target mixed light and convert the transmission optical path of the target mixed light from a first mixed optical path to a second mixed optical path, wherein the first mixed optical path is parallel to and in opposite directions from the second red light path, and the second mixed optical path is parallel to and in opposite directions from the first red light path;

[0036] The third dichroic mirror is disposed on the second mixed light path, and is used to reflect the target continuous green laser light to the first green light path.

[0037] In a possible implementation, when the number of second harmonic conversions is N and all N paths are not collinear, the first conversion component includes M groups of reflection components, a third frequency doubling element, and a third dichroic mirror, wherein N is a positive integer greater than 2, and M is a positive integer less than N by 1;

[0038] The third frequency doubling element is used to receive the target continuous infrared laser transmitted through the second red light path, and perform N-pass conversion on the target continuous infrared laser through the M groups of reflective components to form a target mixed light; the target mixed light includes a target continuous green laser and a target remaining continuous infrared laser;

[0039] The third dichroic mirror is used to transmit the target remaining continuous infrared laser light and reflect the target continuous green laser light to the first green light path.

[0040] In a possible embodiment, each group of reflection components includes a phase compensation element and a light reflection element; the M groups of reflection components are respectively located on opposite sides of the third frequency doubling element, wherein the phase compensation element and the light reflection element in each group of reflection components are spaced apart, and the phase compensation element is close to the third frequency doubling element.

[0041] In a possible implementation, the light reflecting element is a dichroic concave reflecting mirror for reflecting infrared laser and green laser; and the phase compensation element is a quartz plate.

[0042] In a possible implementation manner, the third frequency doubling element is a second harmonic nonlinear crystal of a non-critical phase matching type.

[0043] In a possible implementation, the infrared laser module includes:

[0044] An infrared laser, used for generating initial continuous infrared laser;

[0045] An infrared light adjustment component is arranged on the initial red light path for transmitting the initial continuous infrared laser, and is used to adjust the polarization state of the initial continuous infrared laser to obtain the target continuous infrared laser; the direction of the first red light path for transmitting the target continuous infrared laser is the same as the direction of the initial red light path.

[0046] In a possible implementation, the infrared light adjustment component includes a first polarization beam splitter, a Faraday rotator, a second half-wave plate, a second polarization beam splitter, and a second focusing lens, which are sequentially arranged along the initial red light path; the third dichroic mirror is arranged between the second polarization beam splitter and the second focusing lens;

[0047] The first polarization beam splitter is used to split the initial continuous infrared laser into a third continuous infrared laser and a fourth continuous infrared laser with different polarization directions; wherein the optical path direction of the third continuous infrared laser is the same as that of the initial continuous infrared laser, and the optical path direction of the fourth continuous infrared laser is perpendicular to that of the initial continuous infrared laser;

[0048] The Faraday rotator is used to deflect the polarization state of the incident light beam by 45 degrees;

[0049] The second half-wave plate is used to change the polarization direction of the third continuous infrared laser;

[0050] The second polarization beam splitter is used to split the third continuous infrared laser beam after the polarization direction is changed into a fifth continuous infrared laser beam and a sixth continuous infrared laser beam with different polarization directions; wherein the optical path direction of the fifth continuous infrared laser beam is the same as the optical path direction of the initial continuous infrared laser beam, and the optical path direction of the sixth continuous infrared laser beam is perpendicular to the optical path direction of the initial continuous infrared laser beam;

[0051] The second focusing lens is used to focus the fifth continuous infrared laser into the target continuous infrared laser, and the target continuous infrared laser is incident on the infrared reflector assembly along the first red light path.

[0052] In a possible implementation, the infrared light adjustment component includes a first polarization beam splitter and a second focusing lens which are sequentially arranged at intervals along the initial red light path;

[0053] The first polarization beam splitter is used to split the initial continuous infrared laser into a third continuous infrared laser and a fourth continuous infrared laser with different polarization directions, wherein the optical path direction of the third continuous infrared laser is the same as that of the initial continuous infrared laser, and the optical path direction of the fourth continuous infrared laser is perpendicular to that of the initial continuous infrared laser;

[0054] The second focusing lens is used to focus the third continuous infrared laser into the target continuous infrared laser, and the target continuous infrared laser is incident on the infrared reflector assembly along the first red light path.

[0055] In a possible implementation manner, the infrared light adjustment component further includes:

[0056] The fourth optical power absorber is arranged on the transmission optical path of the fourth continuous infrared laser and is used for absorbing the fourth continuous infrared laser.

[0057] The present disclosure provides a multi-channel continuous deep ultraviolet laser system, comprising the extra-cavity frequency-doubled continuous deep ultraviolet laser device described in any possible embodiment above and a plurality of deep ultraviolet laser modules described in any possible embodiment above;

[0058] The multiple deep ultraviolet laser modules are arranged in layers, and the deep ultraviolet laser modules in each layer are used to receive the second remaining continuous green laser output by the deep ultraviolet laser module in the previous layer, and perform fourth harmonic conversion on the second remaining continuous green laser to convert the second remaining continuous green laser into a target continuous deep ultraviolet laser output.

[0059] The present disclosure provides a semiconductor inspection system, comprising at least one semiconductor to be inspected and the continuous deep ultraviolet laser device described in any of the above possible embodiments or the multi-channel continuous deep ultraviolet laser system described in the above possible embodiments, wherein the continuous deep ultraviolet laser device is used to generate a target continuous deep ultraviolet laser to perform defect detection on the at least one semiconductor to be inspected; the multi-channel continuous deep ultraviolet laser system is used to generate a multi-channel target continuous deep ultraviolet laser, and each target continuous deep ultraviolet laser is used to perform defect detection on a different semiconductor.

[0060] The continuous deep ultraviolet laser device, multi-channel continuous deep ultraviolet laser system and semiconductor detection system provided by the embodiments of the present disclosure can reduce costs and lower environmental requirements compared to the resonant cavity technology in the cavity due to the use of extra-cavity frequency doubling technology. In addition, in the process of second harmonic conversion and the process of fourth harmonic conversion, multi-pass conversion technology is used, which can improve conversion efficiency compared to single-pass conversion.

[0061] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0063] Figure 1 A principle block diagram of an extra-cavity frequency-doubled continuous deep ultraviolet laser device provided by an embodiment of the present disclosure is shown;

[0064] Figure 2 A principle block diagram of another extracavity frequency-doubled continuous deep ultraviolet laser device provided by an embodiment of the present disclosure is shown;

[0065] Figure 3 A schematic structural diagram of a double-pass extracavity frequency-doubled continuous deep ultraviolet laser device provided in an embodiment of the present disclosure is shown;

[0066] Figure 4 A schematic diagram showing the structure of an infrared laser module and a multi-pass green laser module provided in an embodiment of the present disclosure is shown;

[0067] Figure 5 A schematic diagram showing the structure of another infrared laser module and a multi-pass green laser module provided in an embodiment of the present disclosure is shown;

[0068] Figure 6 A schematic diagram showing the structure of another infrared laser module and a multi-pass green laser module provided in an embodiment of the present disclosure is shown;

[0069] Figure 7 A principle block diagram of a multi-channel continuous deep ultraviolet laser system provided by an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical scheme and advantages of the embodiments of the present disclosure clearer, the technical scheme in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The components of the embodiments of the present disclosure generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the present disclosure for protection, but merely represents the selected embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present disclosure.

[0071] In the field of semiconductor inspection (such as wafer inspection), a low-noise, high-stability deep ultraviolet laser is usually required as the inspection light source. Although a high-repetition-rate picosecond deep ultraviolet laser can be regarded as a quasi-continuous light source, it is easy to damage the wafer and explode particles on the wafer due to its relatively high peak power. Therefore, a continuous deep ultraviolet light source is more suitable for defect detection of wafers.

[0072] The main indicators of continuous deep ultraviolet lasers currently used in defect detection are relative intensity noise, output power stability, and output power. The common deep ultraviolet 266nm laser can generate green light 532nm from the infrared 1064nm fundamental frequency light through the second harmonic effect, and the green light then generates 266nm through the fourth harmonic. Among them, the principle of generating continuous deep ultraviolet lasers is very simple, but achieving low noise, high stability, and high power (above 1W) continuous deep ultraviolet lasers is a difficult problem in the industry.

[0073] Research has found that the conversion efficiency of the fourth harmonic can be improved based on the resonant cavity technology to achieve higher power output. However, this technical solution is relatively complex and expensive, the system is relatively sensitive, and has high requirements for vibration, temperature and humidity, resulting in harsh transportation and use conditions and high maintenance costs.

[0074] However, since the conversion efficiency of the nonlinear crystal frequency doubling effect is proportional to the peak power density of the incident light, the square of the crystal length, and the phase matching factor, and inversely proportional to the area of ​​the incident light, when using the continuous optical cavity external harmonic method to generate continuous deep ultraviolet laser, the peak power of the continuous light is the average power, which is much lower than that of the pulsed light, resulting in low conversion efficiency and unable to achieve the required higher power.

[0075] In addition, semiconductor inspection equipment generally limits the power of the light source to within a preset range. For example, wafer inspection equipment generally limits the power of the light source to within 700W. This limits the pump power of the diode, and thus requires the conversion efficiency of the pump to infrared to be increased as much as possible.

[0076] On the other hand, if the infrared power is too high, it is difficult to obtain a narrow linewidth output. That is, due to the limited infrared power, it is necessary to maximize the conversion efficiency of the second harmonic to obtain a sufficiently high green laser light power, and at the same time, maximize the efficiency of the fourth harmonic to obtain a high-power (watt-level) deep ultraviolet laser output. Therefore, how to reduce the technical difficulty while ensuring the conversion efficiency is a technical problem that needs to be solved urgently.

[0077] Based on the above research, the embodiments of the present disclosure provide an extracavity frequency-doubled continuous deep ultraviolet laser device, which can improve conversion efficiency while reducing costs and device complexity.

[0078] The extra-cavity frequency-doubling continuous deep ultraviolet laser device provided by the embodiments of the present disclosure is described in detail below with reference to the accompanying drawings.

[0079] See also Figure 1 As shown, the extracavity frequency-doubling continuous deep ultraviolet laser device 100 provided in the embodiment of the present disclosure includes an infrared laser module 10, a green laser module 20 and a deep ultraviolet laser module 30. The infrared laser module 10 is used to generate a target continuous infrared laser, the green laser module 20 is used to perform multi-pass second harmonic conversion on the target continuous infrared laser to convert the target continuous infrared laser into a target continuous green laser, and the deep ultraviolet laser module 30 is used to perform multi-pass fourth harmonic conversion on the target continuous green laser to convert the target continuous green laser into a target continuous deep ultraviolet laser; the target continuous deep ultraviolet laser is used to detect semiconductors. In the embodiment of the present disclosure, the semiconductor includes a wafer and a mask, etc.

[0080] Specifically, see Figure 2 As shown, the infrared laser module 10 includes an infrared laser 101 and an infrared light adjustment component 102. The infrared laser 101 is used to generate initial continuous infrared laser light. For example, the infrared laser 101 may generally include a polarization-maintaining fiber seed source and a polarization-maintaining fiber amplifier.

[0081] When the order of second harmonic conversion is double-pass, the infrared light adjustment component 102 is arranged on the initial red light path for transmitting the initial continuous infrared laser, and is used to adjust the power and polarization state of the initial continuous infrared laser to obtain the target continuous infrared laser; the direction of the first red light path for transmitting the target continuous infrared laser is the same as the direction of the initial red light path.

[0082] The green laser module 20 includes an infrared reflector assembly 201 and a first conversion assembly 202. The infrared reflector assembly 201 is used to convert the transmission optical path of the target continuous infrared laser from the first red light path to the second red light path. The first conversion assembly 202 is used to perform multi-pass second harmonic conversion on the target continuous infrared laser transmitted through the second red light path to obtain the target continuous green laser.

[0083] The deep ultraviolet laser module includes a green light reflector 301 and a second conversion component 302. The green light reflector 301 is used to convert the transmission optical path of the target continuous green laser from the first green light path to the second green light path. The second conversion component 302 is used to perform multi-pass fourth harmonic conversion on the target continuous green laser transmitted through the second green light path to obtain the target continuous deep ultraviolet laser.

[0084] Exemplarily, the wavelength of the target continuous infrared laser is 1064 nm, the wavelength of the target continuous green laser is 532 nm, and the wavelength of the target continuous deep ultraviolet laser is 266 nm.

[0085] In the embodiments of the present disclosure, multi-pass refers to double pass or triple pass or above. Generally, the fundamental frequency light passing through the nonlinear crystal once can be called a "single pass" structure, that is, the fundamental frequency light has only one conversion effect. Double pass means that the fundamental frequency light passes through the nonlinear crystal twice, that is, the fundamental frequency light achieves two conversion effects. Similarly, multi-pass means that the fundamental frequency light passes through the nonlinear crystal multiple times to achieve multiple conversion effects.

[0086] In the disclosed embodiment, since the continuous deep ultraviolet laser device 100 adopts the extra-cavity frequency doubling technology, it can reduce the cost and reduce the environmental requirements compared with the intra-cavity resonant cavity technology. In addition, in the second harmonic conversion process and the fourth harmonic conversion process, multi-pass conversion technology is adopted, which can improve the conversion efficiency compared with single-pass conversion.

[0087] Understandably, for the infrared laser 101, due to the current fluctuation of the diode, the amplifier spontaneous emission noise (ASE noise) of the amplifier and other factors, the output power will fluctuate. On the other hand, due to the temperature fluctuation of the water chiller, the environment and the optical fiber, the polarization state angle of the polarization-maintaining output will change slowly, which will have a great impact on the subsequent frequency doubling process, resulting in large power fluctuations of the deep ultraviolet laser output. Therefore, the embodiment of the present disclosure proposes an infrared laser module 101 that can achieve stable infrared polarization output.

[0088] Specifically, see Figure 3 ,in Figure 3A schematic diagram of the structure of a double-pass extracavity frequency-doubled continuous deep ultraviolet laser device provided in an embodiment of the present disclosure. In the case where the number of second harmonic conversion is double-pass, the infrared light adjustment component includes a first light-collecting mirror 11, a first power probe 12, a first half-wave plate 13, a polarization beam splitter 14, a second light-collecting mirror 15, a third optical power absorber 16, a first focusing lens 17 and a second power probe 18.

[0089] The first light-collecting mirror 11 is arranged on the initial red light path, and is used to reflect part of the initial continuous infrared laser to the first power probe 12, and output the remaining initial continuous infrared laser. The first power probe 12 is used to detect the power of the initial continuous infrared laser, and when the power of the initial continuous infrared laser exceeds a first preset range, generates a first adjustment instruction; the first adjustment instruction is used to instruct the infrared laser 101 to adjust the power of the initial continuous infrared laser so that the initial continuous infrared laser is within the first preset range.

[0090] The first half-wave plate 13 is arranged on the initial red light path, and is used to change the polarization direction of the initial continuous infrared laser. The polarization beam splitter 14 is arranged on the initial red light path, and is located on the side of the first half-wave plate 13 away from the first light-collecting mirror 11, and is used to split the remaining initial continuous infrared laser after the polarization direction is changed into a first continuous infrared laser and a second continuous infrared laser with different polarization directions; wherein the optical path direction of the first continuous infrared laser is the same as the optical path direction of the initial continuous infrared laser, and the optical path direction of the second continuous infrared laser is perpendicular to the optical path direction of the initial continuous infrared laser.

[0091] The first focusing lens 17 is disposed on the initial red light path, located on the side of the polarization beam splitter 14 away from the first half-wave plate 13, and is used to focus the first continuous infrared laser into the target continuous infrared laser, and the target continuous infrared laser is incident on the infrared reflector assembly 201 along the first red light path. Specifically, the focus of the first focusing lens 17 is consistent with the center of the first frequency doubling element 23, which can improve the conversion efficiency.

[0092] The second light-collecting mirror 15 is arranged in the optical path direction of the second continuous infrared laser, and is used to reflect part of the second continuous infrared laser to the second power probe 18, and output the remaining second continuous infrared laser to the third optical power absorber 16. The second power probe 18 is used to detect the power of the second continuous infrared laser, and the power of the second continuous infrared laser is used to determine whether the power of the first continuous infrared laser exceeds the second preset range; in the case that the power of the first continuous infrared laser exceeds the second preset range, a second adjustment instruction is generated, and the second adjustment instruction is used to instruct the first half-wave plate 13 to adjust the rotation angle so that the power of the first continuous infrared laser is within the second preset range.

[0093] In the infrared laser module 10 provided in the embodiment of the present disclosure, after the infrared laser 101 outputs the initial infrared laser through the fiber collimator, it passes through the first light-collecting mirror 11 and reflects a small part of the light into the first power probe 12 for real-time monitoring. If it exceeds the first preset range, the amplifier current of the infrared laser 101 is adjusted to control the power within the first preset range, thereby realizing the amplifier power negative feedback control system function.

[0094] Furthermore, the combination of the first half-wave plate 13 and the polarization beam splitter 14 can correct the change in the polarization angle of the linear polarized light, and ensure that the power of the light transmitted by the polarization beam splitter 14 remains constant. Specifically, the first half-wave plate 13 and the polarization beam splitter 14 are added behind the first light-collecting mirror 11, and a small part of the S-polarized light (the second continuous infrared laser) reflected from the polarization beam splitter 14 is reflected by the second light-collecting mirror 15 and enters the second power probe 16 for real-time monitoring. If it exceeds the second preset range, the rotation angle of the first half-wave plate 13 is adjusted so that the power of the light transmitted by the polarization beam splitter 14 (the first continuous infrared laser) is controlled within the second preset range, thereby realizing the function of the polarization state automatic correction system.

[0095] Please continue reading Figure 3 The infrared reflector assembly 201 includes a first infrared reflector 21 and a second infrared reflector 22. The first infrared reflector 21 is arranged on the first red light path; the second infrared reflector 22 is arranged on the second red light path.

[0096] Exemplarily, the first conversion component 202 includes a first frequency doubling element 23, a first reflector 24, a first dichroic mirror 25, and a first optical power absorber 26. Specifically, the first frequency doubling element 23 is used to receive the target continuous infrared laser transmitted through the second red light path, and convert part of the target continuous infrared laser into a first continuous green laser. The first continuous green laser and the first remaining continuous infrared laser form a first mixed light.

[0097] The first reflector 24 is disposed on one side of the first frequency doubling element 23, and is used to reflect the received first mixed light to the first frequency doubling element 23, so that the first frequency doubling element 23 converts the reflected part of the first residual continuous infrared laser energy into the first continuous green laser to form the target continuous green laser. The transmission optical path of the target continuous green laser avoids the second infrared reflector 22 in the infrared reflector assembly 201.

[0098] The first dichroic mirror 25 is disposed on a side of the first frequency doubling element 23 away from the first reflector 24, and is used to transmit the second remaining continuous infrared laser light after double-pass conversion by the first frequency doubling element 23 to the first optical power absorber 26, and reflect the target continuous green laser light to the first green light path. The transmission optical path of the second remaining continuous infrared laser light output from the first frequency doubling element 23 avoids the second infrared reflector 22 in the infrared reflector assembly 201.

[0099] Optionally, the first conversion component 202 may further include a first phase compensation element ( Figure 3 Not shown, please refer to Figure 4 The first phase compensation element is arranged between the first frequency doubling element 23 and the first reflector 24, and is used to make the first remaining continuous infrared laser match the first continuous green light phase.

[0100] Optionally, the first reflector 24 is a two-color concave reflector for reflecting infrared laser light and green laser light. The first frequency doubling element 23 is a second harmonic nonlinear crystal of a non-critical phase matching type.

[0101] It should be noted that, when the second harmonic conversion is double-pass, the double-pass paths of the second harmonic are collinear or non-collinear. Collinear means that the two-pass paths of the light beam return along the same path as the one-pass path, and non-collinear means that the two-pass and one-pass paths are misaligned.

[0102] The optical path process of the green laser module 20 is described below.

[0103] After the target infrared continuous laser passes through the first frequency doubling element 23 (second harmonic nonlinear crystal, also called SHG crystal), the continuous green light (first continuous green laser) and the remaining infrared laser (first remaining continuous infrared laser) are refocused to the first frequency doubling element 23 through the concave reflector (first reflector 24), and the second harmonic effect occurs again, further coupling the infrared power to the green light, so that a higher green light power can be obtained. The mixed light beam of infrared light and green light reflected back to the first frequency doubling element 23 has a certain misalignment with the original incident infrared light beam (target infrared continuous laser), so that the mixed light beam can stagger the second infrared reflector 22 and hit the first dichroic mirror 25. The infrared light beam (second remaining continuous infrared laser) is transmitted from the first dichroic mirror 25 and absorbed by the first optical power absorber 26, and does not continue to return to the original incident light path. The green light (target continuous green laser) in the mixed light beam is reflected by the first dichroic mirror 25 and enters the deep ultraviolet laser module 30.

[0104] Here, the first frequency doubling element 23 adopts a non-critical phase matching (NCPM) LBO crystal, and the receiving angle of the fundamental frequency incident light reaches 1718mrad*cm, so that the incident angle of the infrared light beam is not required to be high. Therefore, for the light beam re-reflected back to the first frequency doubling element 23, it is not necessary to re-incident the crystal along the original optical path. The deviation within a certain angle range will not affect the conversion efficiency of the second frequency doubling effect, and thus double-pass second harmonic conversion can be achieved. That is to say, by reusing the remaining infrared light for the second frequency doubling effect, a higher power target continuous green laser can be obtained.

[0105] Please continue reading Figure 3 In some embodiments, when the fourth harmonic conversion order is double-pass, the second conversion component 302 includes a second frequency doubling element 31 , a second reflector 32 and a second dichroic mirror 33 .

[0106] Among them, the second frequency doubling element 31 is arranged on one side of the green light reflector 301, and is used to receive the target continuous green laser transmitted through the second green light optical path, and convert part of the target continuous green laser into a first continuous deep ultraviolet laser, and the first continuous deep ultraviolet laser and the first remaining continuous green laser form a second mixed light.

[0107] The second reflector 32 is arranged on the side of the second frequency doubling element away from the green light reflector 301, and is used to reflect the received second mixed light to the second frequency doubling element 31, so that the second frequency doubling element 31 converts the reflected part of the energy of the first remaining continuous green laser into the first continuous deep ultraviolet light to form the target continuous deep ultraviolet laser; the transmission optical path of the target continuous deep ultraviolet laser avoids the green light reflector.

[0108] The second dichroic mirror 33 is disposed on a side of the second frequency doubling element 31 away from the second reflector 32, and is used to transmit the second residual continuous green laser light after double-pass conversion by the second frequency doubling element 31, and reflect the target continuous deep ultraviolet laser light. The transmission optical path of the second residual continuous green laser light output from the second frequency doubling element 31 avoids the green light reflector.

[0109] Optionally, the second conversion component 302 further includes a second optical power absorber 34 , and the second optical power absorber 34 is used to receive the second residual continuous green laser light transmitted from the second dichroic mirror 33 .

[0110] Optionally, the second conversion component 302 further includes a second phase compensation element ( Figure 3 Not shown, please refer to Figure 4 The second phase compensation element is disposed between the second frequency doubling element 31 and the second reflecting mirror 33, and is used to make the first remaining continuous green laser phase-matched with the first continuous deep ultraviolet laser.

[0111] Here, the phases of the fundamental frequency light and the frequency doubled light can be matched by phase compensation elements (such as the first phase compensation element and the second phase compensation element), so that the frequency doubled light will not flow back to become the fundamental frequency light due to phase mismatch, and the energy of the fundamental frequency light can be further converted into the frequency doubled light, so that the power of the frequency doubled light is further increased and the frequency doubling efficiency is improved.

[0112] It should be understood that, similar to the double-pass second harmonic, the double-pass path of the fourth harmonic may or may not be co-linear.

[0113] In addition, with regard to the multi-pass conversion process of the frequency doubling element, when the fundamental frequency light (such as the target continuous infrared laser) passes through the first frequency doubling element 23 for the first time, a part of the infrared light is converted into green light, but only a small part is used as the seed light for the second frequency doubling. When the mixed light passes through the first frequency doubling element 23 for the second time, the initial phase difference between the frequency doubling seed light and the fundamental frequency light is adjusted to an integer multiple of 2π through phase compensation, and the infrared light of the mixed light will be further converted into green light. In this way, as the number of times passing through the first frequency doubling element 23 increases, it is equivalent to lengthening the length of the first frequency doubling element 23 by multiples, so as to achieve high-efficiency frequency doubling of low peak power lasers.

[0114] Optionally, the second reflector 32 is a dichroic concave reflector for reflecting green laser and deep ultraviolet laser. The second frequency doubling element 31 is a fourth harmonic nonlinear crystal, and the length of the second frequency doubling element 31 is greater than a preset length. For example, the second frequency doubling element 31 can be a β-phase barium borate crystal (also called BBO crystal).

[0115] Optionally, the second conversion component 202 also includes a shaping element 35, which is arranged on the first green light path, and is used to shape the target continuous green laser into an elliptical spot and then output it, the major axis direction of the elliptical spot corresponds to the phase matching direction of the second frequency doubling element 31, and the minor axis direction of the elliptical spot corresponds to the non-phase matching direction of the second frequency doubling element 31.

[0116] Exemplarily, the shaping element 35 may be a diffractive optical element or a cylindrical mirror, the focal plane of the shaping element 35 may coincide with the focal plane of the second dichroic mirror 33 , and the center of the second frequency doubling element 31 is located at the focal plane.

[0117] The elliptical focusing method in the embodiment of the present disclosure can achieve the use of longer crystals and smaller spot areas, which is beneficial to further improve the conversion efficiency.

[0118] It should be noted that, when generating the target continuous green laser, in order to further improve the conversion efficiency, a shaping element may be used to shape the target continuous infrared laser into an elliptical spot and then input to the first frequency doubling element 23 .

[0119] The optical path process of the deep ultraviolet laser module 30 is described below.

[0120] Continuing from the above embodiment, the first dichroic mirror 25 reflects the target continuous green laser light alone, which is transformed into an elliptical spot after passing through the shaping element 35, and is focused to the center of the second frequency doubling element 31 (fourth harmonic nonlinear crystal, also called FHG crystal), and after generating deep ultraviolet laser light (first continuous deep ultraviolet laser light), the remaining green light (first remaining continuous green laser light) is refocused to the second frequency doubling element 31 through the second reflector 32, and the fourth harmonic effect occurs again, further coupling the green laser power to the deep ultraviolet laser light, thereby obtaining a higher power deep ultraviolet laser light. The second mixed light beam reflected back to the second frequency doubling element 31 is misaligned with the original incident green light (target continuous green laser) beam, so that the mixed light beam can miss the green light reflector 301 and hit the second dichroic mirror 33. The green light beam (second remaining continuous green laser) is transmitted from the second dichroic mirror 33 and absorbed by the second optical power absorber 34, while the deep ultraviolet laser in the second mixed light beam is reflected by the second dichroic mirror 33 to obtain the final output target continuous deep ultraviolet laser.

[0121] In some embodiments, in order to further improve the conversion efficiency, the second harmonic conversion can also be performed in an N-pass manner, where N is a positive integer greater than 2. Figure 3 Similarly, the infrared laser module 10 also includes an infrared laser and an infrared light adjustment component 102.

[0122] The difference is that the infrared light adjustment component 102 is arranged on the initial red light path for transmitting the initial continuous infrared laser, and is used to adjust the polarization state of the initial continuous infrared laser to obtain the target continuous infrared laser. The direction of the first red light path for transmitting the target continuous infrared laser is the same as the direction of the initial red light path.

[0123] Specifically, Figure 4 As shown, the infrared light adjustment component 102 includes a first polarization beam splitter 51, a Faraday rotator 52, a second half-wave plate 53, a second polarization beam splitter 54 and a second focusing lens 55 which are sequentially arranged along the initial red light path;

[0124] The first polarization beam splitter 51 is used to split the initial continuous infrared laser into a third continuous infrared laser and a fourth continuous infrared laser with different polarization directions; wherein the optical path direction of the third continuous infrared laser is the same as that of the initial continuous infrared laser, and the optical path direction of the fourth continuous infrared laser is perpendicular to that of the initial continuous infrared laser.

[0125] The Faraday rotator 52 is used to deflect the polarization state of the incident light beam by 45 degrees. The second half-wave plate 53 is used to change the polarization direction of the third continuous infrared laser.

[0126] The second polarization beam splitter 54 is used to split the third continuous infrared laser after the polarization direction is changed into a fifth continuous infrared laser and a sixth continuous infrared laser with different polarization directions; wherein the optical path direction of the fifth continuous infrared laser is the same as the optical path direction of the initial continuous infrared laser, and the optical path direction of the sixth continuous infrared laser is perpendicular to the optical path direction of the initial continuous infrared laser.

[0127] The second focusing lens 55 is used to focus the fifth continuous infrared laser into the target continuous infrared laser, and the target continuous infrared laser is incident on the infrared reflector assembly 201 along the first red light path.

[0128] Optionally, the infrared light adjustment component 102 further includes a fourth optical power absorber 56 , which is disposed on the transmission optical path of the fourth continuous infrared laser and is used to absorb the fourth continuous infrared laser.

[0129] In this embodiment, the number of second harmonic conversion is N passes and the N pass paths are partially collinear, where N is an even number greater than 2, that is, when the number of multi-passes is an even number, the first conversion component 202 may include M groups of reflection components 61, the third frequency doubling element 62 and the third dichroic mirror 63, where M is half of N. For example, in the case of six passes, there are three groups of reflection components 61, and in the case of four passes, there are two groups of reflection components 61.

[0130] The third frequency doubling element 62 is used to receive the target continuous infrared laser transmitted through the second red light path, and convert the target continuous infrared laser into target mixed light after M-pass conversion through the M groups of reflective components 61; the target mixed light includes target continuous green laser and target remaining continuous infrared laser.

[0131] The infrared reflector assembly 201 is also used to receive the target mixed light and convert the transmission optical path of the target mixed light from a first mixed optical path to a second mixed optical path, wherein the first mixed optical path is parallel to and in opposite directions from the second red light path, and the second mixed optical path is parallel to and in opposite directions from the first red light path.

[0132] The third dichroic mirror 63 is disposed on the second mixed light path, and is used to reflect the target continuous green laser light to the first green light path. Specifically, the third dichroic mirror 63 is disposed between the second polarization beam splitter 54 and the second focusing lens 55, and is used to project infrared laser light and reflect green laser light.

[0133] Exemplarily, each group of reflection components 61 includes a phase compensation element 611 (specifically 611a, 611b, 611c) and a light reflection element 612 (specifically 612a, 612b, 612c). The M groups of reflection components 61 are respectively located on opposite sides of the third frequency doubling element 62, wherein the phase compensation element 611 in each group of reflection components 61 is spaced from the light reflection element 612, and the phase compensation element 611 is close to the third frequency doubling element 62.

[0134] Optionally, the light reflecting element 612 is a dichroic concave reflector for reflecting infrared laser and green laser. The phase compensation element 611 is a quartz plate, and the third frequency doubling element 62 is a second harmonic nonlinear crystal of noncritical phase matching type, for example, a lithium triborate (LBO) crystal.

[0135] It should be noted that in multi-pass frequency doubling, when propagating in the air, the wavelengths of the fundamental frequency light and the frequency doubling light are different, and the different refractive index of the air will introduce an additional phase difference, resulting in a certain phase difference between the fundamental frequency light and the frequency doubling light in the return journey. Therefore, in the embodiment of the present disclosure, a quartz plate of a certain thickness is introduced to compensate for the phase difference between the fundamental frequency light and the frequency doubling light, so that the fundamental frequency light and the frequency doubling light are in phase, thereby achieving the effect of multiple frequency doubling enhancement. The phase compensation element here is similar to the aforementioned first phase compensation element and the second phase compensation element, and the third frequency doubling element 62 is similar to the first frequency doubling element 23.

[0136] Below Figure 4 The optical path principle of the multi-pass infrared laser module 10 and the green laser module 20 is explained.

[0137] The initial continuous infrared laser emitted by the infrared laser 101 is transmitted through the first polarization beam splitter 51, and then passes through the Faraday rotator 52 to rotate the polarization of the light by 45 degrees. Then, the polarization direction of the light is adjusted through the second half-wave plate 53. Combined with the function of the second polarization beam splitter 54, the polarization direction of the light is adjusted to the horizontal direction. Then, the light passes through the third dichroic mirror 63 and the second focusing lens 55 to obtain the target continuous infrared laser. The target continuous infrared laser passes through the first infrared reflector 21 and the second infrared reflector 22, and is converted from the first red light path to the second red light path. Then, the target continuous infrared laser passes through the third frequency doubling element 62, and then passes through the phase compensation element 611a to hit the light reflecting element 612a. After the light reflecting element 612a is reflected and converged, it returns to the third frequency doubling element 62, and then passes through the phase compensation element 611b to hit the light reflecting element 612b. After the light reflecting element 612b, it passes through the third frequency doubling element 62 again, and then passes through the phase compensation element 611c to hit the light reflecting element 612c, and after being reflected by the light reflecting element 612c, it passes through the third frequency doubling element 62, passes through the phase compensation element 611b to hit the light reflecting element 612b, passes through the third frequency doubling element 62 again after passing through the light reflecting element 612b, and then passes through the phase compensation element 611a to hit the light reflecting element 612a, and after passing through the light reflecting element 612a, it passes through the third frequency doubling element 62 again to be transmitted to the second infrared reflector 22, and then returns along the original optical path and passes through the third dichroic mirror 63 to extract the target continuous green laser, and the remaining continuous infrared laser will continue to return, pass through the Faraday rotator 52, and the polarization of the light will be rotated by 45°, and the light will be reflected along the first polarization beam splitter 51 to the fourth optical power absorber 56 to be absorbed.

[0138] Specifically, the first optical path is: target continuous infrared laser → first light infrared reflector 21 → second light infrared reflector 22 → third frequency doubling element 62 → phase compensation element 611a → light reflecting element 612a; the second optical path is: light reflecting element 612a → phase compensation element 611a → third frequency doubling element 62 → phase compensation element 611b → light reflecting element 612b; the third optical path is: light reflecting element 612b → phase compensation element 611b → third frequency doubling element 62 → phase compensation element 611c → light reflecting element 612c; the fourth optical path is: Light reflecting element 612c→phase compensation element 611c→third frequency doubling element 62→phase compensation element 611b→light reflecting element 612b; the fifth optical path is: light reflecting element 612b→phase compensation element 611b→third frequency doubling element 62→phase compensation element 611a→light reflecting element 612a; the sixth optical path is: light reflecting element 612a→phase compensation element 611a→third frequency doubling element 62→second light infrared reflector 22→first light infrared reflector 21→second focusing lens 55→third color separation mirror 63→output target continuous green laser.

[0139] It should be noted that the above is only for the case of six channels, and the other cases of four channels or eight channels or more channels are similar. For example, in the case of four channels, a group of reflective components 61 can be reduced on the right side of the third frequency doubling element 62, and optionally, the group of phase compensation element 611a and light reflection element 612a can be removed, or the group of phase compensation element 611c and light reflection element 612c can be removed. In the case of eight channels, another group of reflective components 61 can be added on the left side of the third frequency doubling element 62.

[0140] See also Figure 5 and Figure 6 As shown, when the number of second harmonic conversions is N and all N paths are not collinear, the first conversion component 202 may include M groups of reflection components 61, a third frequency doubling element 62 and a third dichroic mirror 63. In this embodiment, N may be a positive integer greater than 2, and M is a positive integer less than N by 1.

[0141] in, Figure 5 The embodiment in the figure is a three-way optical path with all non-collinear paths. The specific optical paths are as follows:

[0142] The first optical path is: target continuous infrared laser → first light infrared reflector 21 → second light infrared reflector 22 → third frequency doubling element 62 → phase compensation element 611a → light reflecting element 612a; the second optical path is: light reflecting element 612a → phase compensation element 611a → third frequency doubling element 62 → phase compensation element 611b → light reflecting element 612b; the third optical path is: light reflecting element 612b → phase compensation element 611b → third frequency doubling element 62 → third color separation mirror 63 → output target continuous green laser.

[0143] Figure 6 The embodiment in the figure is a case where four channels are not collinear, and the specific optical paths are as follows:

[0144] The first optical path is: target continuous infrared laser → first light infrared reflector 21 → second light infrared reflector 22 → third frequency doubling element 62 → phase compensation element 611a → light reflecting element 612a; the second optical path is: light reflecting element 612a → phase compensation element 611a → third frequency doubling element 62 → phase compensation element 611b → light reflecting element 612b; the third optical path is: light reflecting element 612b → phase compensation element 611b → third frequency doubling element 62 → phase compensation element 611c → light reflecting element 612c; the fourth optical path is: light reflecting element 612c → phase compensation element 611c → third frequency doubling element 62 → third color separation mirror 63 → output target continuous green laser.

[0145] against Figure 5 and Figure 6 In the embodiment, Figure 4 The difference between the embodiment is that the third dichroic mirror 63 is disposed at a different position, and the target mixed light does not pass through the infrared reflector assembly 201 but is directly emitted (reflected) through the third dichroic mirror 63 .

[0146] In addition, in this embodiment, the infrared light adjustment component 102 and Figure 4 In this embodiment, the infrared light adjustment component 102 includes a first polarization beam splitter 51 and a second focusing lens 55 which are arranged in sequence along the initial red light path. The first polarization beam splitter 51 is used to split the initial continuous infrared laser into a third continuous infrared laser and a fourth continuous infrared laser with different polarization directions, wherein the optical path direction of the third continuous infrared laser is the same as that of the initial continuous infrared laser, and the optical path direction of the fourth continuous infrared laser is perpendicular to that of the initial continuous infrared laser. The second focusing lens 55 is used to focus the third continuous infrared laser into the target continuous infrared laser, and the target continuous infrared laser is incident on the infrared reflector component 201 along the first red light path.

[0147] In addition, Figure 5 and Figure 6 In the embodiment of the target mixed light, the target residual continuous infrared laser in the target mixed light can be emitted through the third dichroic mirror 63 and then pass through the fifth optical power absorber 64 (see Figure 5 shown) absorption.

[0148] In addition, it should be noted that Figure 4 The infrared light adjustment component 102 in the embodiment may also include Figure 3 The second light collecting mirror 15, the third optical power absorber 16 and the second power probe 18 are arranged in the middle, so that the power of the light separated by the second polarization beam splitter 54 can be detected, and then the rotation angle of the second half-wave plate 53 can be adjusted according to the detection result.

[0149] See also Figure 7 As shown, it is a principle block diagram of a multi-channel continuous deep ultraviolet laser system provided by an embodiment of the present disclosure. The multi-channel continuous deep ultraviolet laser system 1000 includes the extracavity frequency-doubling continuous deep ultraviolet laser device 100 described in any of the foregoing embodiments and a plurality of deep ultraviolet laser modules 30 described in any of the foregoing embodiments. The plurality of deep ultraviolet laser modules 30 are arranged in a hierarchical manner, and the deep ultraviolet laser modules 30 of each level are used to receive the second residual continuous green laser output by the deep ultraviolet laser module 30 of the previous level, and perform fourth harmonic conversion on the second residual continuous green laser to convert the second residual continuous green laser into a target continuous deep ultraviolet laser output.

[0150] In addition, the present disclosure provides a semiconductor inspection system. In some embodiments, the semiconductor inspection system includes at least one semiconductor to be inspected and the continuous deep ultraviolet laser device 100 described in any of the foregoing embodiments. The continuous deep ultraviolet laser device 100 is used to generate a target continuous deep ultraviolet laser to perform defect detection on the at least one semiconductor to be inspected. In other embodiments, the semiconductor inspection system includes at least one semiconductor to be inspected and the multi-channel continuous deep ultraviolet laser system 1000 described in any of the foregoing embodiments. The multi-channel continuous deep ultraviolet laser system 1000 is used to generate multiple target continuous deep ultraviolet lasers, and each target continuous deep ultraviolet laser is used to perform defect detection on different semiconductors.

[0151] Of course, the target continuous deep ultraviolet laser generated by the continuous deep ultraviolet laser device 100 can also be used in the fields of packaging of electronic components, marking, drilling, welding, cutting of industrial parts, etc., which can be determined according to actual needs.

[0152] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0153] The embodiments described above are part of the embodiments of the present disclosure, but not all of them. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the embodiments of the present disclosure.

[0154] In the description of the embodiments of the present disclosure, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the disclosed product is usually placed when in use. They are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the electric laser system or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present disclosure. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0155] In the description of the present disclosure, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0156] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present disclosure, which are used to illustrate the technical solutions of the present disclosure, rather than to limit them. The protection scope of the present disclosure is not limited thereto. Although the present disclosure is described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the aforementioned embodiments within the technical scope disclosed in the present disclosure, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure. They should all be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims

1. An extracavity frequency-doubled continuous deep ultraviolet laser device, characterized in that: It includes an infrared laser module, a green laser module and a deep ultraviolet laser module; wherein the infrared laser module is used to generate a target continuous infrared laser, the green laser module is used to perform multi-pass second harmonic conversion on the target continuous infrared laser to convert the target continuous infrared laser into a target continuous green laser, and the deep ultraviolet laser module is used to perform multi-pass fourth harmonic conversion on the target continuous green laser to convert the target continuous green laser into a target continuous deep ultraviolet laser; the target continuous deep ultraviolet laser is used to detect semiconductors; The green laser module includes an infrared reflector assembly and a first conversion assembly; the infrared reflector assembly is used to convert the transmission optical path of the target continuous infrared laser into a second red light path through a first red light path; the first conversion assembly is used to perform multi-pass second harmonic conversion on the target continuous infrared laser transmitted through the second red light path to obtain the target continuous green laser; The deep ultraviolet laser module includes a green light reflector and a second conversion component. The green light reflector is used to convert the transmission optical path of the target continuous green laser from a first green light path to a second green light path; the second conversion component is used to perform multi-pass fourth harmonic conversion on the target continuous green laser transmitted through the second green light path to obtain the target continuous deep ultraviolet laser.

2. The laser device according to claim 1, characterized in that The order of second harmonic conversion is double pass, and the first conversion component includes a first frequency doubling element, a first reflector, a first dichroic mirror and a first optical power absorber; The first frequency doubling element is used to receive the target continuous infrared laser transmitted through the second red light path, and convert part of the target continuous infrared laser into a first continuous green laser, wherein the first continuous green laser and the first remaining continuous infrared laser form a first mixed light; The first reflector is disposed at one side of the first frequency doubling element, and is used to reflect the received first mixed light to the first frequency doubling element, so that the first frequency doubling element converts the reflected part of the first residual continuous infrared laser energy into the first continuous green laser to form the target continuous green laser; the transmission optical path of the target continuous green laser avoids the infrared reflector assembly; The first dichroic mirror is arranged on a side of the first frequency doubling element away from the first reflector, and is used to transmit the second remaining continuous infrared laser after double-pass conversion by the first frequency doubling element to the first optical power absorber, and reflect the target continuous green laser to the first green light path; the transmission light path of the second remaining continuous infrared laser output from the first frequency doubling element avoids the infrared reflector assembly.

3. The laser device according to claim 2, characterized in that: The first conversion component further includes a first phase compensation element, which is disposed between the first frequency doubling element and the first reflector and is used to match the phase of the first residual continuous infrared laser light with the first continuous green light.

4. The laser device according to any one of claims 1 to 3, characterized in that: The fourth harmonic conversion is double-pass, and the second conversion component includes a second frequency doubling element, a second reflector, and a second dichroic mirror; The second frequency doubling element is disposed on one side of the green light reflector, and is used to receive the target continuous green laser transmitted through the second green light path, and convert part of the target continuous green laser into a first continuous deep ultraviolet laser, wherein the first continuous deep ultraviolet laser and the first remaining continuous green laser form a second mixed light; The second reflector is arranged on a side of the second frequency doubling element away from the green light reflector, and is used to reflect the received second mixed light to the second frequency doubling element, so that the second frequency doubling element converts the reflected part of the first residual continuous green laser energy into the first continuous deep ultraviolet light to form the target continuous deep ultraviolet laser; the transmission optical path of the target continuous deep ultraviolet laser avoids the green light reflector; The second dichroic mirror is arranged on a side of the second frequency doubling element away from the second reflector, and is used to transmit the second remaining continuous green laser after double-pass conversion by the second frequency doubling element and reflect the target continuous deep ultraviolet laser; the transmission optical path of the second remaining continuous green laser output from the second frequency doubling element avoids the green light reflector.

5. The laser device according to claim 4, characterized in that The second conversion component further includes a second phase compensation element, which is disposed between the second frequency doubling element and the second reflector and is used to achieve phase matching between the first residual continuous green laser and the first continuous deep ultraviolet laser.

6. The laser device according to claim 2, characterized in that: The first reflector is a dichroic concave reflector for reflecting infrared laser and green laser; and / or the first frequency doubling element is a second harmonic nonlinear crystal of a non-critical phase matching type.

7. The laser device according to claim 4, characterized in that The second reflector is a dichroic concave reflector for reflecting green laser and deep ultraviolet laser; and / or the second frequency doubling element is a fourth harmonic nonlinear crystal, and the length of the second frequency doubling element is greater than a preset length.

8. The laser device according to claim 1, characterized in that The infrared reflector assembly includes a first infrared reflector and a second infrared reflector. The first infrared reflector is arranged on the first red light path; the second infrared reflector is arranged on the second red light path.

9. The laser device according to claim 4, characterized in that: The second conversion component also includes a shaping element, which is arranged on the first green light path and is used to shape the target continuous green laser into an elliptical spot and then output it, the major axis direction of the elliptical spot corresponds to the phase matching direction of the second frequency doubling element, and the minor axis direction of the elliptical spot corresponds to the non-phase matching direction of the second frequency doubling element.

10. The laser device according to claim 1, characterized in that The infrared laser module comprises: An infrared laser, used for generating initial continuous infrared laser; An infrared light adjustment component is arranged on the initial red light path for transmitting the initial continuous infrared laser, and is used to adjust the power and polarization state of the initial continuous infrared laser to obtain the target continuous infrared laser; the direction of the first red light path for transmitting the target continuous infrared laser is the same as the direction of the initial red light path.

11. The laser device according to claim 10, characterized in that The infrared light adjustment component comprises: A first light-collecting mirror is arranged on the initial red light path, and is used to reflect part of the initial continuous infrared laser to the first power probe, and output the remaining initial continuous infrared laser; The first power sensor is used to detect the power of the initial continuous infrared laser, and to generate a first adjustment instruction when the power of the initial continuous infrared laser exceeds a first preset range; the first adjustment instruction is used to instruct the infrared laser to adjust the power of the initial continuous infrared laser so that the initial continuous infrared laser is within the first preset range; A first half-wave plate, arranged on the initial red light path, for changing the polarization direction of the initial continuous infrared laser; A polarization beam splitter is arranged on the optical path of the initial red light and is located on the side of the first half-wave plate away from the first light-collecting mirror, and is used to split the remaining initial continuous infrared laser after the polarization direction is changed into a first continuous infrared laser and a second continuous infrared laser with different polarization directions; wherein the optical path direction of the first continuous infrared laser is the same as the optical path direction of the initial continuous infrared laser, and the optical path direction of the second continuous infrared laser is perpendicular to the optical path direction of the initial continuous infrared laser; A first focusing lens is arranged on the initial red light path and is located on a side of the polarization beam splitter away from the first half-wave plate, and is used for focusing the first continuous infrared laser into the target continuous infrared laser, and the target continuous infrared laser is incident on the infrared reflector assembly along the first red light path; A second light-collecting mirror is arranged in the optical path direction of the second continuous infrared laser, and is used to reflect a part of the second continuous infrared laser to the second power probe, and output the remaining second continuous infrared laser to the third optical power absorber; The second power sensor is used to detect the power of the second continuous infrared laser, and the power of the second continuous infrared laser is used to determine whether the power of the first continuous infrared laser exceeds a second preset range; When the power of the first continuous infrared laser exceeds the second preset range, a second adjustment instruction is generated, and the second adjustment instruction is used to instruct the half-wave plate to adjust the rotation angle so that the power of the first continuous infrared laser is within the second preset range.

12. The laser device according to claim 1, characterized in that The number of second harmonic conversions is N passes and the N pass paths are partially collinear, wherein N is an even number greater than 2, and the first conversion component includes M groups of reflection components, a third frequency doubling element, and a third dichroic mirror, wherein M is half of N; The third frequency doubling element is used to receive the target continuous infrared laser transmitted through the second red light path, and perform N-pass conversion on the target continuous infrared laser through the M groups of reflective components to form a target mixed light; the target mixed light includes a target continuous green laser and a target remaining continuous infrared laser; The infrared reflector assembly is also used to receive the target mixed light and convert the transmission optical path of the target mixed light from a first mixed optical path to a second mixed optical path, wherein the first mixed optical path is parallel to and in opposite directions from the second red light path, and the second mixed optical path is parallel to and in opposite directions from the first red light path; The third dichroic mirror is disposed on the second mixed light path, and is used to reflect the target continuous green laser light to the first green light path.

13. The laser device according to claim 1, characterized in that The number of second harmonic conversions is N passes and all N pass paths are not collinear, the first conversion component includes M groups of reflection components, a third frequency doubling element and a third dichroic mirror, wherein N is a positive integer greater than 2, and M is a positive integer less than N by 1; The third frequency doubling element is used to receive the target continuous infrared laser transmitted through the second red light path, and perform N-pass conversion on the target continuous infrared laser through the M groups of reflective components to form a target mixed light; the target mixed light includes a target continuous green laser and a target remaining continuous infrared laser; The third dichroic mirror is used to transmit the target remaining continuous infrared laser light and reflect the target continuous green laser light to the first green light path.

14. The laser device according to claim 12 or 13, characterized in that: Each group of reflection components includes a phase compensation element and a light reflection element; the M groups of reflection components are respectively located on opposite sides of the third frequency doubling element, wherein the phase compensation element and the light reflection element in each group of reflection components are spaced apart, and the phase compensation element is close to the third frequency doubling element.

15. The laser device according to claim 14, characterized in that The light reflecting element is a two-color concave reflecting mirror for reflecting infrared laser and green laser; the phase compensation element is a quartz plate.

16. The laser device according to claim 12 or 13, characterized in that: The third frequency doubling element is a second harmonic nonlinear crystal of a non-critical phase matching type.

17. The laser device according to claim 12 or 13, characterized in that: The infrared laser module comprises: An infrared laser, used for generating initial continuous infrared laser; An infrared light adjustment component is arranged on the initial red light path for transmitting the initial continuous infrared laser, and is used to adjust the polarization state of the initial continuous infrared laser to obtain the target continuous infrared laser; the direction of the first red light path for transmitting the target continuous infrared laser is the same as the direction of the initial red light path.

18. The laser device according to claim 17, characterized in that The infrared light adjustment component comprises a first polarization beam splitter, a Faraday rotator, a second half-wave plate, a second polarization beam splitter and a second focusing lens which are sequentially arranged along the initial red light path; the third dichroic mirror is arranged between the second polarization beam splitter and the second focusing lens; The first polarization beam splitter is used to split the initial continuous infrared laser into a third continuous infrared laser and a fourth continuous infrared laser with different polarization directions; wherein the optical path direction of the third continuous infrared laser is the same as that of the initial continuous infrared laser, and the optical path direction of the fourth continuous infrared laser is perpendicular to that of the initial continuous infrared laser; The Faraday rotator is used to deflect the polarization state of the incident light beam by 45 degrees; The second half-wave plate is used to change the polarization direction of the third continuous infrared laser; The second polarization beam splitter is used to split the third continuous infrared laser beam after the polarization direction is changed into a fifth continuous infrared laser beam and a sixth continuous infrared laser beam with different polarization directions; wherein the optical path direction of the fifth continuous infrared laser beam is the same as the optical path direction of the initial continuous infrared laser beam, and the optical path direction of the sixth continuous infrared laser beam is perpendicular to the optical path direction of the initial continuous infrared laser beam; The second focusing lens is used to focus the fifth continuous infrared laser into the target continuous infrared laser, and the target continuous infrared laser is incident on the infrared reflector assembly along the first red light path.

19. The laser device according to claim 17, characterized in that The infrared light adjustment component comprises a first polarization beam splitter and a second focusing lens which are sequentially arranged at intervals along the initial red light path; The first polarization beam splitter is used to split the initial continuous infrared laser into a third continuous infrared laser and a fourth continuous infrared laser with different polarization directions, wherein the optical path direction of the third continuous infrared laser is the same as that of the initial continuous infrared laser, and the optical path direction of the fourth continuous infrared laser is perpendicular to that of the initial continuous infrared laser; The second focusing lens is used to focus the third continuous infrared laser into the target continuous infrared laser, and the target continuous infrared laser is incident on the infrared reflector assembly along the first red light path.

20. The laser device according to claim 18 or 19, characterized in that: The infrared light adjustment component also includes: The fourth optical power absorber is arranged on the transmission optical path of the fourth continuous infrared laser and is used for absorbing the fourth continuous infrared laser.

21. A multi-channel continuous deep ultraviolet laser system, characterized in that: It comprises an extracavity frequency-doubled continuous deep ultraviolet laser device according to any one of claims 1 to 20 and a plurality of deep ultraviolet laser modules according to any one of claims 1 to 20; The multiple deep ultraviolet laser modules are arranged in layers, and the deep ultraviolet laser modules in each layer are used to receive the second remaining continuous green laser output by the deep ultraviolet laser module in the previous layer, and perform fourth harmonic conversion on the second remaining continuous green laser to convert the second remaining continuous green laser into a target continuous deep ultraviolet laser output.

22. A semiconductor testing system, characterized in that: It comprises at least one semiconductor to be inspected and a continuous deep ultraviolet laser device according to any one of claims 1 to 20 or a multi-channel continuous deep ultraviolet laser system according to claim 21, wherein the continuous deep ultraviolet laser device is used to generate a target continuous deep ultraviolet laser to perform defect detection on the at least one semiconductor to be inspected; and the multi-channel continuous deep ultraviolet laser system is used to generate multiple target continuous deep ultraviolet lasers, each target continuous deep ultraviolet laser is used to perform defect detection on a different semiconductor.

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