Optical detection equipment and control method thereof

Abstract

The invention relates to the technical field of optical detection, in particular to optical detection equipment and a control method thereof.The optical detection equipment comprises a defect detection device, the defect detection device comprises a large defect avoiding system and an illumination system, the illumination system is used for emitting high-power illumination light to scan a sample, and when the illumination system scans a large defect on the sample, the large defect avoiding system detects the large defect on the sample; the large defect avoiding system is used for sending a shutter closing signal to the illumination system to close the high-power illumination light, so that the large defect on the sample avoids scanning of the high-power illumination light; the air purification device comprises a light engine cabin wind field system, and the light engine cabin wind field system comprises a first blowing assembly for blowing first blowing airflow to the lighting system; the large defect avoidance system sends a shutter closing signal and also sends a first purging signal to the first purging assembly, and the first purging assembly receiving the first purging signal increases the air pressure of the first purging airflow. The invention is at least beneficial to improving the performance of the optical detection equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical detection, and in particular relates to an optical detection device and a control method thereof. Background Art

[0002] The presence of defects on the wafer may cause chip failure and requires detection during the manufacturing process. Wafer defect detection based on dark field scattering is an optical defect detection method. It collects scattered light from the wafer surface to make defect judgments. It has the advantages of high sensitivity and fast speed and is widely used in wafer detection.

[0003] The high-precision dark field scattering wafer defect detection system mainly uses high-power, short-wavelength lasers as the detection light source. Increasing the illumination power of the detection light source can increase the scattering signal intensity of defects of the same size, thereby increasing the detection sensitivity. However, high illumination power also places higher requirements on the purification system of the detection equipment. Although the detection equipment is usually equipped with an air purification system, pollution such as dust particles still inevitably exist and fall on optical components such as lenses. Pollution under high illumination power will produce thermal effects, which may damage the film layer on the optical components, causing the performance of the detection equipment to deteriorate or even fail. In order to deal with the pollution problem, the relevant technology introduces a device for purging optical components in the air purification system to effectively reduce the pollution of the optical components. However, low-pressure purging is not strong enough to remove some pollution, and high-pressure purging will cause the optical components to shake, which will cause the illumination light to shake, resulting in a decrease in detection positioning accuracy.

[0004] Therefore, how to clean the optical components without affecting the dark field scattering wafer defect detection parameters as much as possible is a key issue that needs to be solved in the wafer defect detection system. Summary of the invention

[0005] In view of this, the present invention aims to provide an optical detection device and a control method thereof, which are at least beneficial to improving the performance of the optical detection device.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: On the one hand, the present invention provides an optical inspection device, including: a defect detection device, the defect detection device includes a large defect avoidance system and an illumination system, the illumination system is used to emit high-power illumination light to scan a sample, when the illumination system scans a large defect on the sample, the large defect avoidance system is used to send a shutter closing signal to the illumination system to turn off the high-power illumination light, so that the large defects on the sample avoid being scanned by the high-power illumination light; an air purification device, the air purification device includes an optical chamber wind field system, the optical chamber wind field system includes a first purge component that blows a first purge airflow to the illumination system; wherein, the large defect avoidance system sends a shutter closing signal while also sending a first purge signal to the first purge component, and the first purge component that receives the first purge signal increases the air pressure of the first purge airflow.

[0007] Furthermore, the first purge assembly includes a first control unit and a first air intake assembly, the first air intake assembly is used to blow a first purge airflow, and the first control unit is used to receive a first purge signal and control the first air intake assembly to increase the air pressure of the first purge airflow.

[0008] Furthermore, the first purge component also includes a first exhaust component, and per unit time, the air intake volume of the first air intake component is smaller than the air exhaust volume of the first exhaust component.

[0009] Furthermore, the optical detection equipment also includes an optical machine room shell, which encloses the optical machine room, and the lighting system is arranged in the optical machine room. The first exhaust component includes a first exhaust duct and a first exhaust fan. The optical machine room is connected to the first end of the first exhaust duct through the first exhaust port, and the other end of the first exhaust duct is connected to the first exhaust fan.

[0010] Furthermore, the lighting system includes a light source component, a power regulation component, a light spot stabilization component, a light spot modulation component and a signal collection component.

[0011] Furthermore, the lighting system includes a plurality of optical elements, and the optical chamber wind farm system includes a plurality of first air intake components, and a first air intake component is used to achieve purging of one or more optical elements.

[0012] Furthermore, the optical element is fixed in the optical machine chamber by using a damping structure.

[0013] Furthermore, the damping structure includes a main body and a bearing part, the bearing part is connected to the main body through a spring, the bearing part is used to set the optical element, and the main body is set in the optical machine chamber.

[0014] Furthermore, the first purge component has a stable purge mode and an instantaneous purge mode. The air pressure of the first purge airflow in the instantaneous purge mode is greater than the air pressure of the first purge airflow in the stable purge mode. When the high-power lighting light is turned on, the first purge component is in the stable purge mode, and at least the first purge component that receives the first purge signal is in the instantaneous purge mode.

[0015] Furthermore, the lighting system also includes a beam power and quality monitoring unit, which is used to monitor the optical power of the illumination light or the spot distribution of the illumination light. When the optical power of the illumination light is abnormal or the spot distribution of the illumination light is abnormal, the beam power and quality monitoring unit sends a second purge signal to the first purge component, and the first purge component that receives the second purge signal and the first purge signal enters an instantaneous purge mode.

[0016] Furthermore, the first purge component has N instantaneous purge modes, and the air pressure of the first purge airflow corresponding to the N instantaneous purge modes increases gradually. After the first purge component adopts the instantaneous purge mode with lower air pressure to purge the lighting system, if the first purge component still receives the second purge signal, the first purge component will adopt the instantaneous purge mode with higher air pressure to purge the lighting system when it receives the first purge signal again.

[0017] Furthermore, the beam power and quality monitoring unit includes: a detection unit, which is used to obtain a light signal formed by the optical elements in the lighting system processing the illumination light; and a processing unit, which is used to determine whether the light power of the illumination light is abnormal, or whether the spot distribution of the illumination light is abnormal, based on the light signal.

[0018] Furthermore, the detection unit includes: an optical signal detection element and a control element, the optical signal detection element is used to obtain the optical signal, and the control element is used to control the optical signal detection element to switch in or out of the transmission optical path of the optical signal.

[0019] Furthermore, the detection unit includes: an optical signal detection element and a spectroscopic element, the spectroscopic element is arranged on the transmission optical path of the optical signal to split the optical signal into a first optical signal and a second optical signal, the transmission directions of the first optical signal and the second optical signal are different, the optical signal detection element receives the first optical signal to detect the illumination light, and the second optical signal is used for sample scanning.

[0020] Furthermore, the defect detection device also includes a scanning detection system, which is used to carry the sample and move it to achieve detection of different positions of the sample; the air purification device also includes a detection bin wind field system, which includes at least a second purge component for blowing a second purge airflow to the scanning detection system.

[0021] Furthermore, the second purge component includes a second control unit, a second air intake component and a second exhaust component, and the second control unit is used to control the air intake volume of the second air intake component, and to control the exhaust volume of the second exhaust component, so that the air intake volume of the second air intake component is equal to the exhaust volume of the second exhaust component per unit time.

[0022] Furthermore, the optical detection equipment also includes a detection shell, which encloses a detection cavity, and the scanning detection system is arranged in the detection cavity. The second exhaust component includes a second exhaust duct and a second exhaust fan. The detection cavity is connected to the first end of the second exhaust duct through the second exhaust port, and the other end of the second exhaust duct is connected to the second exhaust fan.

[0023] Furthermore, the second air intake assembly includes a second air intake pipe and a uniform wind structure. The uniform wind structure is arranged at one end of the second air intake pipe extending into the detection cavity, and the uniform wind structure is located above the sample. The second purge air flow is blown out from the uniform wind structure through the second air intake pipe, and the direction of the second purge air flow blown out from the uniform wind structure is parallel to the direction of the sample surface.

[0024] Furthermore, the uniform wind structure includes a uniform wind grid and a fan-shaped uniform wind portion. The side of one end of the second air inlet pipe connected to the uniform wind structure has an air outlet. The uniform wind grid is arranged at the air outlet at intervals along the circumference of the second air inlet pipe. The fan-shaped uniform wind portion has a uniform wind cavity, which is connected to the air outlet. The side of the fan-shaped uniform wind portion away from the air outlet has a plurality of uniform wind holes. The second purge airflow blown out of the air outlet passes through the uniform wind cavity and then flows into the detection cavity through the uniform wind holes.

[0025] Another aspect of the present invention provides a control method for an optical inspection device, comprising: providing the above-mentioned optical inspection device, the optical inspection device comprising a defect detection device and an air purification device, the defect detection device comprising a large defect avoidance system and a lighting system, the air purification device comprising an optical chamber wind field system, the optical chamber wind field system comprising a first purge component for blowing a first purge airflow to the lighting system; the control method for the optical inspection device comprises: when the lighting system scans a large defect on a sample, using the large defect avoidance system to send a shutter closing signal to the lighting system to turn off the high-power lighting light, so that the large defects on the sample avoid being scanned by the high-power lighting light; wherein, the large defect avoidance system sends a first purge signal to the first purge component while sending the shutter closing signal, and the first purge component receiving the first purge signal increases the air pressure of the first purge airflow.

[0026] Compared with the prior art, the invention can achieve the following beneficial effects: the optical inspection equipment provided by the embodiment of the invention is generally a wafer dark field defect inspection equipment, which includes an air purification device, the air purification device includes an optical chamber wind field system, the optical chamber wind field system is used to purify the air of the lighting system to solve the problem that the pollution in the optical chamber falls on the optical elements during the inspection, causing the light source to fluctuate or the optical elements to be damaged, the optical chamber wind field system includes a first purge component, the first purge component works together with the large defect avoidance system, when a large defect is encountered during the dark field inspection and the high-power illumination light is shut down to skip the inspection, an instantaneous high-pressure purge is performed in the optical chamber, thereby increasing the ability to remove pollution on the optical elements and avoiding the influence of the jitter caused by the purge on the lighting system, thereby solving the problem of reduced detection accuracy due to purge. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 A modular schematic diagram of an optical detection device according to an embodiment of the present invention; Figure 2 A partial structural schematic diagram of an optical detection device according to an embodiment of the present invention; Figure 3 A schematic diagram of the structure of the power control component according to an embodiment of the present invention; Figure 4 A schematic diagram of the three-dimensional structure of the damping structure according to an embodiment of the present invention; Figure 5 A side schematic diagram of a damping structure according to an embodiment of the present invention; Figure 6 A schematic diagram of the structure of the uniform wind structure described in the embodiment of the present invention; Figure 7 A spot diagram of a light signal formed by light processed by an optical element obtained by a detection unit provided in an embodiment of the present invention; Figure 8 for Figure 7 A local magnified view of the light spot shown; Fig. 9 for Figure 7 The light signal intensity distribution curve of the light spot shown is at position X=a in the long side direction along the short side direction; Fig.10 for Figure 7 The light signal intensity distribution curve of the light spot shown is along its long side. DETAILED DESCRIPTION

[0028] After analysis, it was found that for the contamination problem in the wafer inspection equipment in the existing technology, the effective solutions of the relevant technology mainly include the following two categories. The first category is to perform atmospheric pressure purging when the equipment is not inspecting. When the wafer inspection result is abnormal, this method can only stop the equipment for cleaning the pollution and then re-inspect after cleaning the pollution, which has an impact on the equipment throughput; the second category is to improve the air intake component, rectify the purge gas generated by it, and reduce the jitter of the purge gas. However, this method has limited limits in solving the jitter and cannot completely eliminate the jitter.

[0029] In order to solve the above problems, an embodiment of the present invention provides an optical detection device, which does not require the device to be stopped for purging and can avoid the influence of the jitter generated by the purging on the detection accuracy.

[0030] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0031] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0032] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0033] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" 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 components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0034] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0035] refer to Figure 1The optical inspection equipment includes: a defect detection device, the defect detection device includes a large defect avoidance system 11 and an illumination system 10, the illumination system 10 is used to emit high-power illumination light to scan the sample, when the illumination system 10 scans a large defect on the sample, the large defect avoidance system 11 is used to send a shutter closing signal to the illumination system 10 to turn off the high-power illumination light, so that the large defects on the sample avoid being scanned by the high-power illumination light; an air purification device, the air purification device includes an optical chamber 101 wind field system, the optical chamber 101 wind field system includes a first purge component that blows a first purge airflow to the illumination system 10; wherein, the large defect avoidance system 11 sends a shutter closing signal while also sending a first purge signal to the first purge component, and the first purge component that receives the first purge signal increases the air pressure of the first purge airflow.

[0036] The samples involved in the embodiments of the present invention are usually semiconductor substrates such as wafers or chips used to form chips.

[0037] The defect detection device is at least used to realize dark field defect detection of wafers. It should be noted that for wafer defect detection devices based on dark field scattering, high-power illumination light can improve signal strength, but it may also cause thermal damage problems. Depending on the different thermal damage objects, thermal damage can generally be divided into the following two categories: Category 1: The surface defects of the wafer under test are damaged due to absorption of illumination light and generation of heat. This thermal damage will directly lead to damage to the sample under test. The higher the illumination light power or the larger the defect, the more obvious the thermal effect and the greater the possibility of damage. When such large defects that may cause thermal damage exist, the size and position information of the large defect can be obtained in the low-power illumination mode. High-power illumination may cause sample damage. In order to prevent such damage, a large defect avoidance system 11 may be provided in the dark field defect detection device. The large defect avoidance system 11 uses low-power illumination light for pre-inspection before using high-power illumination light for formal detection to obtain the size and position information of the large defect and predict the possibility of damage. For large defects caused by scratches, high-power scanning detection is performed. When scanning to these designated large defect positions, the large defect avoidance system 11 sends a shutter closing signal to the lighting system 10, and manipulates the shutter of the lighting system 10 to quickly turn off the illumination light, thereby skipping the detection of these large defects. The large defect avoidance system 11 provided in the embodiment of the present invention has multiple implementation methods. For example, the large defect avoidance system 11 includes two parallel detection systems, one for low-power pre-scanning and the other for high-power detection; or, the same detection system is used to scan twice, the first time using low-power illumination light scanning, and the second time using high-power illumination light scanning. The embodiment of the present invention does not limit the specific structure of the large defect avoidance system 11.

[0038] The second category: pollution falls on the optical elements of the lighting system 10, and the pollution absorbs the illumination light to cause damage to the optical elements. Although this type of damage will not damage the sample, it will cause changes in the illumination conditions and affect the detection parameters. To address this problem, the present invention combines the large defect avoidance system 11 to control the pressure of the first purge airflow blown out by the first purge component of the wind field system of the optical chamber 101. When the large defect avoidance system 11 gives a shutter closing signal, the optical elements are purged with instantaneous atmospheric pressure to purge the pollution on the optical elements. The purge is performed within the time when the illumination light is turned off, thereby reducing the impact of the jitter caused by the purge on the detection accuracy and avoiding the impact of the purge on the equipment throughput.

[0039] In some embodiments, the first purge assembly includes a first control unit and a first air intake assembly 110, the first air intake assembly 110 is used to blow a first purge airflow to the lighting system, the first control unit is used to receive a first purge signal and control the first air intake assembly 110 to increase the air pressure of the first purge airflow.

[0040] In some embodiments, the first purge assembly also includes a first exhaust assembly. Per unit time, the air intake volume of the first air intake assembly 110 is less than the air exhaust volume of the first exhaust assembly, so that the optical chamber 101 where the lighting system is set is in a slightly negative pressure state.

[0041] In some embodiments, per unit time, the air intake volume of the first air intake assembly 110 is slightly smaller than the air exhaust volume of the first exhaust assembly.

[0042] In some embodiments, reference Figure 2 The optical detection device further includes an optical machine room housing 100, which encloses an optical machine room 101. The lighting system 10 is disposed in the optical machine room 101. The first exhaust assembly includes a first exhaust pipe 111 and a first exhaust fan 112. The optical machine room 101 is connected to a first end of the first exhaust pipe 111 through a first exhaust port, and the other end of the first exhaust pipe 111 is connected to the first exhaust fan 112. The first exhaust fan 112 continuously draws air to discharge the gas in the optical machine room 101 to the outside of the device.

[0043] In some embodiments, the first air inlet assembly 110 includes a first air inlet pipe and a first purge end. The first air inlet pipe is used to introduce purified clean air into the first purge end, and the first purge end is used to blow a first purge gas toward the optical element.

[0044] In some embodiments, reference Figure 1The lighting system 10 includes a light source component, a power control component, a light spot stabilization component, a light spot modulation component and a signal collection component. The light source component, the power control component, the light spot stabilization component, the light spot modulation component and the signal collection component cooperate to complete a series of processes such as the generation, stabilization, modulation and signal light collection of the illumination light. These components mainly include active optical components such as lasers and passive optical components such as optical lenses, reflectors and polarizers.

[0045] In some embodiments, each component in the lighting system 10 is provided with one or more first purge components, and the first purge end of the first purge component is aligned to the irradiation point of the key optical element. The following is an example of a power control component. Figure 3 The power control component corresponds to two first air intake components 110 and a first exhaust component. The power control component includes a first mirror frame 160 and a second mirror frame 161. The first mirror frame is used to set the first optical element, and the second mirror frame is used to set the second optical element. One of the two first air intake components 110 is used to purge the first optical element, and the other first air intake component 110 is used to purge the second optical element. The first optical element and the second optical element are arranged in a closed cavity. In order to reduce the vibration of the optical element caused by the instantaneous high pressure purge, the first mirror frame and the second mirror frame can be used. Figure 4 and Figure 5 The damping structure shown enables the optical element directly swept by the first sweeping end to be in a critical damping state when swept by atmospheric airflow.

[0046] In some embodiments, the optical element is fixed in the optical engine chamber 101 by using a damping structure. In this way, it can be ensured that the optical element quickly returns to a balanced position after being purged by the first purge airflow with a relatively high air pressure.

[0047] In some embodiments, the damping structure includes a main body 141 and a bearing portion 140 , the bearing portion 140 is connected to the main body 141 via a spring 144 , the bearing portion 140 is used to set an optical element, and the main body 141 is set in the optical machine chamber 101 .

[0048] Specifically, refer to Figure 4 and Figure 5 The damping structure can be provided with a plurality of springs 144. For example, three springs 144 can be provided. The stretching degree of the spring 144 can be changed by rotating the nut 143, and the angle of the loaded optical element can be accurately adjusted from three angles, thereby realizing arbitrary fine adjustment of the stereoscopic angle and spatial position of the optical element. The thickness of the spring 144 can be selected according to the wind pressure reaching the optical element during high-pressure blowing to realize damping control of the optical element.

[0049] In some embodiments, the lighting system 10 includes a plurality of optical elements, and the wind farm system of the optical engine room 101 includes a plurality of first air intake components 110, and one first air intake component 110 is used to achieve purging of one or more optical elements.

[0050] It should be noted that, with respect to the optical engine compartment 101 , except for the light inlet and the light outlet, the optical engine compartment 101 is sealed and not connected to the outside, presenting a nearly independent chamber.

[0051] In some embodiments, the first purge component has a stable purge mode and an instantaneous purge mode. The air pressure of the first purge airflow in the instantaneous purge mode is greater than the air pressure of the first purge airflow in the stable purge mode. When the high-power lighting light is turned on, the first purge component is in the stable purge mode, and at least the first purge component that receives the first purge signal is in the instantaneous purge mode.

[0052] In some embodiments, the lighting system 10 also includes a beam power and quality monitoring unit, which is used to monitor the optical power of the illumination light or the spot distribution of the illumination light. When the optical power of the illumination light is abnormal or the spot distribution of the illumination light is abnormal, the beam power and quality monitoring unit sends a second purge signal to the first purge component, and the first purge component that receives the second purge signal and the first purge signal enters an instantaneous purge mode.

[0053] The beam power and quality monitoring unit is arranged in the light spot modulation system. When the illumination light power is abnormal or the illumination light spot distribution is abnormal, it may be due to the optical element being polluted by dust or the like, which leads to the light power abnormality or the light spot abnormality. Therefore, the abnormality detected can be used as a condition for triggering the instantaneous purge mode with a higher air pressure. That is to say, in some embodiments, the instantaneous purge mode is not switched to when large defects are avoided. The instantaneous purge mode is turned on when large defect avoidance is turned on and the light spot modulation system detects the illumination light abnormality.

[0054] In some embodiments, the first purge component has N instantaneous purge modes, and the air pressure of the first purge airflow corresponding to the N instantaneous purge modes increases gradually. After the first purge component uses the instantaneous purge mode with a lower air pressure to purge the lighting system 10, if the first purge component still receives the second purge signal, the first purge component uses the instantaneous purge mode with a higher air pressure to purge the lighting system 10 when it receives the first purge signal again. In other words, when the lighting light quality is still not restored after the purge in the low-level mode, the purge mode with a higher air pressure will be turned on next time.

[0055] In some embodiments, the beam power and quality monitoring unit includes: a detection unit, which is used to obtain a light signal formed by the optical elements in the lighting system 10 processing the illumination light; and a processing unit, which is used to determine whether the light power of the illumination light is abnormal, or whether the spot distribution of the illumination light is abnormal, based on the light signal.

[0056] In some embodiments, the detection unit includes: an optical signal detection element and a control element, the optical signal detection element is used to obtain an optical signal, and the control element is used to control the optical signal detection element to switch in or out of a transmission optical path of the optical signal.

[0057] In one embodiment of the present invention, when the optical signal detection element is located on the transmission optical path of the optical signal, the optical signal is vertically irradiated onto the optical signal detection element to improve the accuracy of acquiring the optical signal using the optical signal detection element.

[0058] Specifically, in one embodiment of the present invention, the optical element is a reflective optical element, the optical signal detection element is located on the transmission optical path of the reflected light signal formed by the light emitted by the reflective optical element, and is fixedly connected to the control element; in another embodiment of the present invention, the optical element is a transmissive optical element, the optical signal detection element is located on the transmission optical path of the transmitted light signal formed by the light emitted by the transmissive optical element, and is fixedly connected to the control element.

[0059] In some embodiments, the detection unit includes: an optical signal detection element and a spectroscopic element, the spectroscopic element is arranged on the transmission optical path of the optical signal to separate the optical signal into a first optical signal and a second optical signal, the transmission directions of the first optical signal and the second optical signal are different, the optical signal detection element receives the first optical signal to detect the illumination light, and the second optical signal is used for sample scanning. In other words, the second optical signal is used to ensure the normal operation of the optical element, which is conducive to further reducing the influence of the process of the optical signal detection element acquiring the optical signal on the normal operation of the optical element.

[0060] In some embodiments of the present invention, the detection unit includes an optical signal detection element and a target element. The target element is located on the transmission optical path of the optical signal. The optical signal acquired by the optical signal detection element is an optical signal formed by the optical element processing light and irradiating the target element with the light signal.

[0061] Optionally, in one embodiment of the present invention, the optical signal detection element obtains the optical signal formed by the optical signal processed by the optical element on the target object based on the scattered signal formed by the optical signal formed by the optical signal processed by the optical element irradiating the target element. Optionally, in one embodiment of the present invention, the target element is a wafer, and the optical signal obtained by the optical signal detection element is a scattered light signal formed on the wafer when the light signal formed by the optical element processed light is irradiated on the wafer, but the present invention is not limited to this and it depends on the specific circumstances.

[0062] Specifically, Figure 7 As shown, Figure 7 The light spot diagram of the light signal formed by the light processed by the optical element obtained by the detection unit and irradiated on the target element, wherein the X direction is defined as the long side direction of the light spot, and the Y direction is defined as the short side direction of the light spot. Figure 8 for Figure 7 A partial enlarged view of Figure 7 In the light spot diagram shown, the cross section of the light spot is cut at various positions along its long side, for example, Figure 8 The white line shown in FIG. 1 intercepts the light spot, and similarly, the light signal intensity distribution curve of the light spot at each position in the long side direction and in the short side direction can be obtained, such as Fig. 9 As shown, on this basis, the light signal intensity distribution curve of the light spot in the long side direction can be further obtained, as shown in Fig.10 As shown. The formula for spot uniformity is defined as: ; Among them, I max is the maximum light signal intensity of the light spot, I min is the minimum light signal intensity of the light spot. From the above formula, we can see that Fig.10 On the basis of the maximum light signal intensity of the light spot that has been obtained, the light spot uniformity can be set to obtain the minimum light signal intensity that satisfies the preset uniformity in the light spot, and then the size of the area that satisfies the preset uniformity in the light spot can be obtained. Therefore, in an embodiment of the present invention, it is possible to judge whether the light spot distribution of the illumination light is abnormal based on the length of the area that satisfies the preset uniformity in the light spot of the light signal formed by the optical element processing the light, and / or the width of the light spot area. When the length of the area that satisfies the preset uniformity in the light spot of the light signal formed by the optical element processing the light is less than the first preset value, and / or the width of the light spot area is greater than the second preset value, it indicates that the optical element may be contaminated and the detection accuracy cannot be guaranteed. The present invention does not limit the first preset value and the second preset value, and they can be set specifically according to the needs of the user and the detection accuracy requirements of the optical detection equipment.

[0063] In some embodiments, reference Figure 1 The defect detection device also includes a scanning detection system, which is used to carry the sample and move it to realize the detection of different positions of the sample; the scanning detection system is mainly faced with the first type of damage mentioned above; the air purification device also includes a detection bin wind field system, which is used to purify the air of the scanning detection system, and the detection bin wind field system at least includes a second purge component for blowing a second purge airflow to the scanning detection system.

[0064] In some embodiments, the second purge assembly includes a second control unit, a second air intake assembly 120 and a second exhaust assembly, the second control unit being used to control the air intake volume of the second air intake assembly 120, and to control the air exhaust volume of the second exhaust assembly, so that the air intake volume of the second air intake assembly 120 per unit time is equal to the air exhaust volume of the second exhaust assembly.

[0065] For the scanning and detecting chamber 131 , the second air inlet assembly 120 does not directly purge the sample and equipment components, but ensures that the air intake volume per unit time is equal to the air exhaust volume through the second control unit, so that the scanning and detecting chamber 131 presents a zero-pressure structure.

[0066] In some embodiments, reference Figure 2 The optical detection device also includes a detection shell 130, which encloses a detection cavity 131. The scanning detection system is arranged in the detection cavity 131. The second exhaust component includes a second exhaust duct 121 and a second exhaust fan 122. The detection cavity 131 is connected to the first end of the second exhaust duct 121 through the second exhaust port, and the other end of the second exhaust duct 121 is connected to the second exhaust fan 122.

[0067] In some embodiments, reference Figure 6 The second air intake assembly 120 includes a second air intake pipe and a uniform wind structure. The uniform wind structure is arranged at one end of the second air intake pipe extending into the detection cavity 131, and the uniform wind structure is located above the sample. The second purge air flow is blown out from the uniform wind structure through the second air intake pipe, and the direction of the second purge air flow blown out from the uniform wind structure is parallel to the direction of the sample surface.

[0068] In some embodiments, the uniform wind structure includes a uniform wind grid 153 and a fan-shaped uniform wind portion 150. The side of one end of the second air inlet pipe connected to the uniform wind structure has an air outlet. The uniform wind grid 153 is arranged at the air outlet at intervals along the circumference of the second air inlet pipe. The fan-shaped uniform wind portion 150 has a uniform wind cavity 152, which is connected to the air outlet. The side of the fan-shaped uniform wind portion 150 away from the air outlet has multiple uniform wind holes 151. The second purge airflow blown out of the air outlet passes through the uniform wind cavity 152 and then flows into the detection cavity 131 through the uniform wind holes 151.

[0069] In this way, a stable laminar flow protection can be formed on the scanning surface, and the air flow disturbance in the rest of the space is small, which will not easily arouse particle contamination and reduce the risk of contaminating the sample.

[0070] The present invention also provides a control method for an optical inspection device, including: providing any of the above optical inspection devices, the optical inspection device including a defect detection device and an air purification device, the defect detection device including a large defect avoidance system 11 and a lighting system 10, the air purification device including an optical chamber 101 wind field system, the optical chamber 101 wind field system including a first purge component for blowing a first purge airflow to the lighting system 10; the control method for the optical inspection device includes: when the lighting system 10 scans a large defect on the sample, using the large defect avoidance system 11 to send a first purge airflow to the lighting system 10 The shutter signal is turned off to turn off the high-power illumination light so that large defects on the sample can avoid being scanned by the high-power illumination light; wherein, the large defect avoidance system 11 sends a shutter-closing signal while also sending a first purge signal to the first purge component, and the first purge component receiving the first purge signal increases the air pressure of the first purge airflow, and after turning off the high-power illumination light to skip scanning large defects on the sample, the shutter is opened to continue scanning the sample along the scanning path with the high-power illumination light, and the air pressure of the first purge airflow is reduced while opening the shutter, i.e., the instantaneous purge mode is turned off to return to normal purge.

[0071] In the optical detection equipment provided by the present invention, when the large defect avoidance system 11 reaches the large defect position, it simultaneously gives a shutter closing signal and a first purge signal. At this time, increasing the air pressure of the first purge airflow can achieve the effect of cleaning and purging the optical element. Since no light passes through the lighting system 10 when the shutter is closed, the jitter of the optical element caused by the strong wind will not affect the detection accuracy of the optical detection equipment. In addition, adding a damping structure can accelerate the elimination of the jitter, and opening the shutter after passing the large defect area will not affect the optical detection, thereby achieving the effect of strong wind enhancing the cleaning of the optical element without affecting the optical detection. In addition, strong wind blowing and cleaning are achieved during detection, which improves efficiency and avoids affecting the equipment throughput.

[0072] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0073] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical detection device, characterized in that: include: A defect detection device, the defect detection device comprising a large defect avoidance system and an illumination system, the illumination system being used to emit high-power illumination light to scan a sample, and when the illumination system scans a large defect on the sample, the large defect avoidance system being used to send a shutter closing signal to the illumination system to close the high-power illumination light, so that the large defect on the sample avoids the scanning of the high-power illumination light; An air purification device, the air purification device comprising an optical machine room wind farm system, the optical machine room wind farm system comprising a first purge component that blows a first purge airflow toward the lighting system; Wherein, the large defect avoidance system sends the shutter closing signal and also sends a first purge signal to the first purge component. The first purge component that receives the first purge signal increases the pressure of the first purge airflow.

2. The optical detection device according to claim 1, characterized in that: The first purge assembly includes a first control unit and a first air intake assembly, the first air intake assembly is used to blow the first purge airflow, and the first control unit is used to receive the first purge signal and control the first air intake assembly to increase the air pressure of the first purge airflow.

3. The optical detection device according to claim 2, characterized in that: The first purge component also includes a first exhaust component. In a unit time, the air intake volume of the first air intake component is smaller than the air exhaust volume of the first exhaust component.

4. The optical detection device according to claim 3, characterized in that: The optical detection equipment also includes an optical machine room shell, which encloses an optical machine room. The lighting system is arranged in the optical machine room. The first exhaust component includes a first exhaust duct and a first exhaust fan. The optical machine room is connected to the first end of the first exhaust duct through a first exhaust port, and the other end of the first exhaust duct is connected to the first exhaust fan.

5. The optical detection device according to claim 4, characterized in that: The lighting system includes a light source component, a power regulation component, a light spot stabilization component, a light spot modulation component and a signal collection component.

6. The optical detection device according to claim 4, characterized in that: The lighting system includes a plurality of optical elements, and the optical chamber wind farm system includes a plurality of first air intake components, one of the first air intake components being used to achieve purging of one or more of the optical elements.

7. The optical detection device according to claim 6, characterized in that: The optical element is fixed in the optical machine chamber by using a damping structure.

8. The optical detection device according to claim 7, characterized in that: The damping structure includes a main body and a bearing part, the bearing part is connected to the main body through a spring, the bearing part is used to set the optical element, and the main body is set in the optical machine chamber.

9. The optical detection device according to claim 1, characterized in that: The first purge component has a stable purge mode and an instantaneous purge mode. The air pressure of the first purge airflow in the instantaneous purge mode is greater than the air pressure of the first purge airflow in the stable purge mode. When the high-power lighting light is turned on, the first purge component is in the stable purge mode. At least the first purge component that receives the first purge signal is in the instantaneous purge mode.

10. The optical detection device according to claim 9, characterized in that: The lighting system also includes a beam power and quality monitoring unit, which is used to monitor the optical power of the illumination light or the spot distribution of the illumination light. When the optical power of the illumination light is abnormal or the spot distribution of the illumination light is abnormal, the beam power and quality monitoring unit sends a second purge signal to the first purge component, and the first purge component that receives the second purge signal and the first purge signal enters the instantaneous purge mode.

11. The optical detection device according to claim 10, characterized in that: The first purge component has N instantaneous purge modes, and the air pressure of the first purge airflow corresponding to the N instantaneous purge modes increases gradually. After the first purge component adopts the instantaneous purge mode with lower air pressure to purge the lighting system, if the first purge component still receives the second purge signal, the first purge component adopts the instantaneous purge mode with higher air pressure to purge the lighting system when it receives the first purge signal again.

12. The optical detection device according to claim 10, characterized in that: The beam power and quality monitoring unit includes: a detection unit, which is used to obtain a light signal formed by the optical element in the lighting system processing the illumination light; and a processing unit, which is used to determine whether the light power of the illumination light is abnormal, or whether the spot distribution of the illumination light is abnormal based on the light signal.

13. The optical detection device according to claim 12, characterized in that: The detection unit includes: an optical signal detection element and a control element, wherein the optical signal detection element is used to obtain the optical signal, and the control element is used to control the optical signal detection element to switch in or out of the transmission optical path of the optical signal.

14. The optical detection device according to claim 12, characterized in that: The detection unit includes: an optical signal detection element and a spectroscopic element. The spectroscopic element is arranged on the transmission optical path of the optical signal to separate the optical signal into a first optical signal and a second optical signal. The transmission directions of the first optical signal and the second optical signal are different. The optical signal detection element receives the first optical signal to detect the illumination light, and the second optical signal is used for scanning the sample.

15. The optical detection device according to claim 1, characterized in that: The defect detection device further includes a scanning detection system, and the scanning detection system is used to carry the sample to move so as to realize detection of different positions of the sample; The air purification device further comprises a detection chamber wind field system, and the detection chamber wind field system at least comprises a second purge component for blowing a second purge airflow toward the scanning detection system.

16. The optical detection device according to claim 15, characterized in that: The second purge assembly includes a second control unit, a second air intake assembly and a second exhaust assembly. The second control unit is used to control the air intake volume of the second air intake assembly and to control the air exhaust volume of the second exhaust assembly so that the air intake volume of the second air intake assembly is equal to the air exhaust volume of the second exhaust assembly per unit time.

17. The optical detection device according to claim 16, characterized in that: The optical detection device also includes a detection shell, which encloses a detection cavity. The scanning detection system is arranged in the detection cavity. The second exhaust component includes a second exhaust duct and a second exhaust fan. The detection cavity is connected to the first end of the second exhaust duct through a second exhaust port, and the other end of the second exhaust duct is connected to the second exhaust fan.

18. The optical detection device according to claim 17, characterized in that: The second air intake assembly includes a second air intake pipe and a uniform wind structure, wherein the uniform wind structure is arranged at one end of the second air intake pipe extending into the detection cavity, and the uniform wind structure is located above the sample, and the second purge air flow is blown out from the uniform wind structure through the second air intake pipe, and the direction of the second purge air flow blown out from the uniform wind structure is parallel to the direction of the sample surface.

19. The optical detection device according to claim 18, characterized in that: The uniform wind structure includes a uniform wind grid and a fan-shaped uniform wind portion. The side of one end of the second air inlet pipe connected to the uniform wind structure has an air outlet. The uniform wind grid is arranged at intervals at the air outlet along the circumference of the second air inlet pipe. The fan-shaped uniform wind portion has a uniform wind cavity, which is connected to the air outlet. The side of the fan-shaped uniform wind portion away from the air outlet has a plurality of uniform wind holes. The second purge airflow blown out of the air outlet passes through the uniform wind cavity and then flows into the detection cavity through the uniform wind holes.

20. A control method for an optical detection device, characterized in that: include: Provided is an optical inspection device according to any one of claims 1 to 19, the optical inspection device comprising a defect detection device and an air purification device, the defect detection device comprising a large defect avoidance system and a lighting system, the air purification device comprising an optical machine room wind field system, the optical machine room wind field system comprising a first purge component that blows a first purge airflow toward the lighting system; The control method of the optical inspection device comprises: when the illumination system scans a large defect on a sample, using the large defect avoidance system to send a shutter closing signal to the illumination system to close the high-power illumination light, so that the large defect on the sample avoids the scanning of the high-power illumination light; Wherein, the large defect avoidance system sends the shutter closing signal and also sends a first purge signal to the first purge component. The first purge component that receives the first purge signal increases the pressure of the first purge airflow.

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