Wafer detection device and detection method
By adjusting the laser power and spot size according to the position in wafer detection, the thermal stress damage caused by long-term laser irradiation in the central area of the wafer is solved, and efficient detection accuracy and safety are achieved.
Patent Information
- Application Number
- CN202410553513.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-07
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2044-05-07
AI Technical Summary
In the existing wafer detection technology, the area near the rotation center is heat accumulation due to long-term laser irradiation, which generates thermal stress and causes wafer damage.
By determining the theoretical incident position of the laser light before the laser exit module emits the laser, and controlling the first power laser light when it is within the preset position range, controlling the second power laser light when it is outside the preset position range, using a small power Small spots are detected in the central area, and high-power large spots are detected in the edge area to avoid damage caused by heat accumulation.
It effectively avoids thermal stress damage caused by long-term laser irradiation in the central area of the wafer, while ensuring detection accuracy and efficiency.
Smart Images
Figure CN118483249B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of optical detection technology, and in particular to a wafer detection device and a detection method. Background Art
[0002] The optical technologies for detecting surface defects of unpatterned wafers mainly include interference method, diffraction method and scattering method. Among them, the dark field scattering technology in the scattering method has the characteristics of high sensitivity and efficiency, so it is widely used in actual production.
[0003] The scattering method determines the surface defects by detecting the scattered light intensity on the wafer surface. It converts the collected scattered light intensity into the equivalent size of the defect through the established "correlation curve" of the scattered light intensity of polystyrene latex particles with standard diameter.
[0004] The current wafer inspection path is generally a spiral inspection path, so the area close to the rotation center is subjected to laser irradiation for a longer time. At this time, the thermal stress generated by the accumulation of heat may cause wafer damage. Summary of the invention
[0005] The embodiments of the present invention provide a wafer detection device and a detection method to avoid wafer damage caused by heat accumulation in the center area of the wafer.
[0006] In a first aspect, an embodiment of the present invention provides a wafer detection device, including: a laser emission module, a scattering module and a control module;
[0007] The laser emitting module is used to emit laser light to the wafer;
[0008] The scattering module is used to detect the actual scattered light intensity after being scattered by the particles in the wafer;
[0009] The control module is electrically connected to the scattering module, and is used to obtain the actual scattered light intensity, and determine the defect of the wafer according to the actual scattered light intensity;
[0010] The control module is also electrically connected to the laser emission module, and is used to determine the theoretical incident position of the laser light on the wafer before the laser emission module emits laser, and when the theoretical incident position is within a preset position range, control the laser emission module to emit a first-power laser light; when the theoretical incident position is outside the preset position range, control the laser emission module to emit a second-power laser light.
[0011] Optionally, the wafer detection device further includes: a light spot switching module;
[0012] The light spot switching module is located in the optical path between the laser emitting module and the wafer;
[0013] The control module is also electrically connected to the light spot switching module, and is used to control the light spot switching module to switch the first-power laser light to the first light spot when the laser emission module emits the first-power laser light; and to control the light spot switching module to switch the second-power laser light to the second light spot when the laser emission module emits the second-power laser light; the spot area of the first light spot is smaller than the spot area of the second light spot.
[0014] Optionally, the spot area of the first light spot is positively correlated with the power of the first-power laser light, and the spot area of the second light spot is positively correlated with the power of the second-power laser light.
[0015] Optionally, the power P1 of the first-power laser light, the power P2 of the second-power laser light, the spot area S1 of the first light spot, and the spot area S2 of the second light spot satisfy: |(P1 / S1)-(P2 / S2)| / (P1 / S1)≤10%;
[0016] Among them, P1, P2, S1 and S2 are all positive numbers.
[0017] Optionally, the wafer detection device further includes: a light adjustment module;
[0018] The light adjustment module is located in the light path between the laser emission module and the wafer, and is used to reflect the laser light to the surface of the wafer at a preset angle;
[0019] The control module is electrically connected to the light adjustment module, and is used to determine the theoretical incident position according to the relative position relationship between the laser emission module and the light adjustment module, the relative position relationship between the light adjustment module and the wafer, and the deflection angle of the light adjustment module.
[0020] Optionally, the scattering module includes: a focusing lens unit and a light detection unit;
[0021] The focusing lens unit and the light detection unit are sequentially located in the light path of the scattered light;
[0022] The light detection unit is electrically connected to the control module, and is used to detect the light intensity of the scattered light after being focused by the focusing lens unit, and transmit the light intensity to the control module.
[0023] Optionally, the wafer detection device further includes: a reflection module;
[0024] The reflection module is used to receive the reflected light after the laser light is reflected by the wafer;
[0025] The control module is also electrically connected to the reflection module, and is used to adjust the position where the laser light is incident on the wafer according to the change in the position of the reflected light.
[0026] Optionally, the wafer detection device further includes: a motion module;
[0027] The motion module is located on a side of the wafer away from the laser emission module, and is used to drive the wafer to rotate around the center of the wafer and translate along a first direction; the first direction is the direction from the center of the wafer to the edge of the wafer.
[0028] In a second aspect, an embodiment of the present invention further provides a wafer detection method, which is applied to the wafer detection device according to any one of the first aspects, and the wafer detection method includes:
[0029] Determine the theoretical incident position of the laser light on the wafer, and when the theoretical incident position is within a preset position range, control the laser emission module to emit a first-power laser light; when the theoretical incident position is outside the preset position range, control the laser emission module to emit a second-power laser light;
[0030] The actual scattered light intensity is obtained, and the defect of the wafer is determined according to the actual scattered light intensity.
[0031] Optionally, the laser emission module includes: a light spot switching module; the light spot switching module is located in the optical path between the laser emission module and the wafer;
[0032] Before obtaining the actual scattered light intensity and determining the defect of the wafer according to the actual scattered light intensity, the method further includes:
[0033] When the laser emitting module emits the first-power laser light, controlling the light spot switching module to switch the first-power laser light to a first light spot;
[0034] When the laser emitting module emits the second-power laser light, the light spot switching module is controlled to switch the second-power laser light to a second light spot; the light spot area of the first light spot is smaller than the light spot area of the second light spot.
[0035] The technical solution of the embodiment of the present invention is that the scattering module is used to detect the actual scattered light intensity after being scattered by the particles in the wafer, and the control module is used to obtain the actual scattered light intensity, and determine the defects of the wafer according to the actual scattered light intensity. Before the laser emission module emits the laser, the theoretical incident position of the laser light on the wafer is determined, and when the theoretical incident position is within the preset position range, the laser emission module is controlled to emit a first-power laser light; when the theoretical incident position is outside the preset position range, the laser emission module is controlled to emit a second-power laser light. In other words, the laser power used when detecting the area within the preset position range of the wafer is different from the laser power used when detecting the area outside the preset position range of the wafer. The laser power within the preset position range is less than the laser power outside the preset position range, which can avoid the central area of the wafer from being subjected to laser irradiation for a long time, and the thermal stress generated by the heat accumulation causes wafer damage. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] Figure 1 A schematic structural diagram of a first wafer inspection device provided by an embodiment of the present invention;
[0037] Figure 2 A connection diagram of a control module in a wafer inspection device provided by an embodiment of the present invention;
[0038] Figure 3 A schematic structural diagram of a second wafer inspection device provided by an embodiment of the present invention;
[0039] Figure 4 A schematic flow chart of a first wafer inspection method provided by an embodiment of the present invention;
[0040] Figure 5 A schematic flow chart of a second wafer inspection method provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.
[0042] Figure 1 A schematic diagram of the structure of a first wafer inspection device provided by an embodiment of the present invention, Figure 2 A connection diagram of a control module in a wafer inspection device provided by an embodiment of the present invention is shown in FIG. Figure 1 and Figure 2As shown, the wafer detection device includes a laser emitting module 10, a scattering module 20 and a control module 30; the laser emitting module 10 is used to emit laser light to the wafer 40; the scattering module 20 is used to detect the actual scattered light intensity after being scattered by particles in the wafer 40; the control module 30 is electrically connected to the scattering module 20, and is used to obtain the actual scattered light intensity, and determine the defects of the wafer 40 according to the actual scattered light intensity; the control module 30 is also electrically connected to the laser emitting module 10, and is used to determine the theoretical incident position of the laser light on the wafer 40 before the laser emitting module 10 emits the laser, and when the theoretical incident position is within the preset position range, control the laser emitting module 10 to emit a first-power laser light; when the theoretical incident position is outside the preset position range, control the laser emitting module 10 to emit a second-power laser light.
[0043] Specifically, the laser output module 10 includes a laser light source, which emits laser light to the wafer 40. The scattered light is scattered by particles in the wafer 40 and then incident on the scattering module 20. The scattering module 20 can detect the intensity of the scattered light. The control module 30 is electrically connected to the scattering module 20 to obtain the actual intensity of the scattered light and determine the defects of the wafer 40, such as the size, quantity and distribution of the defects of the wafer, based on the actual intensity of the scattered light.
[0044] Optional, continue to refer to Figure 1 The wafer detection device also includes: a light adjustment module 50; the light adjustment module 50 is located in the optical path between the laser emitting module 10 and the wafer 40, and is used to reflect the laser light to the surface of the wafer 40 at a preset angle; the control module 30 is electrically connected to the light adjustment module 50, and is used to determine the theoretical incident position according to the relative position relationship between the laser emitting module 10 and the light adjustment module 50, the relative position relationship between the light adjustment module 50 and the wafer 40, and the deflection angle of the light adjustment module 50.
[0045] Specifically, the light adjustment module 50 may be a reflector, which can reflect the laser light incident on the surface of the light adjustment module 50 to the surface of the wafer 40 at a preset angle. Furthermore, the theoretical incident position of the laser light incident on the surface of the wafer 40 is related to the relative position relationship between the laser output module 10 and the light adjustment module 50, the relative position relationship between the light adjustment module 50 and the wafer 40, and the deflection angle of the light adjustment module 50. The theoretical incident position can be changed by adjusting any of the above parameters.
[0046] Specifically, since the detection path in the process of detecting the wafer 40 is spiral, that is, starting from the center of the wafer 40, the laser light is used to scan the wafer from the inside to the outside. In the spiral detection path, the linear velocity near the center area of the wafer 40 is slow, and the linear velocity near the edge area of the wafer 40 is fast. In this way, when moving the same path, the detection time of the center area of the wafer 40 is greater than the detection time of the edge area of the wafer. As a comparative example, when a laser beam of the same power is used to irradiate the wafer 40, since the center area of the wafer 40 is subjected to a longer laser irradiation, the thermal stress generated by the accumulation of heat will cause wafer damage. However, in the embodiment of the present invention, the theoretical incident position of the laser light on the wafer 40 is determined before the laser emission module 10 emits the laser, and when the theoretical incident position is within the preset position range, the laser emission module 10 is controlled to emit a first power laser light; when the theoretical incident position is outside the preset position range, the laser emission module 10 is controlled to emit a second power laser light. Specifically, the preset position range can be understood as a position range between a certain position near the center of the wafer 40 and the center of the wafer. It should be noted that the power of the first-power laser light is less than the power of the second-power laser light, so that the control module 30 can control the laser output module 10 to emit a low-power laser light, and then use the low-power laser light to scan the area within the preset position range of the wafer 40; the control module 30 can control the laser output module 10 to emit a high-power laser light, and then use the high-power laser light to scan the area outside the preset position range of the wafer 40, so as to avoid heat accumulation caused by long-term irradiation of the central area of the wafer 40 and causing wafer damage.
[0047] The wafer detection device provided by the embodiment of the present invention determines the theoretical incident position of the laser light on the wafer before the laser emission module emits the laser, and when the theoretical incident position is within the preset position range, controls the laser emission module to emit a laser light of the first power; when the theoretical incident position is outside the preset position range, controls the laser emission module to emit a laser light of the second power. In other words, the laser power used when detecting the area within the preset position range of the wafer is different from the laser power used when detecting the area outside the preset position range of the wafer. The laser power within the preset position range is less than the laser power outside the preset position range, which can prevent the central area of the wafer from being subjected to laser irradiation for a long time, and the thermal stress generated by the heat accumulation causes wafer damage.
[0048] Optional, continue to refer to Figure 1The wafer detection device also includes: a spot switching module 60; the spot switching module 60 is located in the optical path between the laser emission module 10 and the wafer 40; the control module 30 is also electrically connected to the spot switching module 60, and is used to control the spot switching module 60 to switch the first-power laser light to the first spot when the laser emission module 10 emits a first-power laser light; when the laser emission module 10 emits a second-power laser light, the spot switching module 60 is controlled to switch the second-power laser light to the second spot; the spot area of the first spot is smaller than the spot area of the second spot.
[0049] Specifically, the laser light emitted by the laser emission module 10 can be switched into a large light spot or a small light spot through the light spot switching module 60. The spot area of the first light spot is smaller than the spot area of the second light spot, that is, the first light spot is a small light spot, and the second light spot is a large light spot. When the laser emission module 10 emits a first-power laser light, the light spot switching module 60 is controlled to switch the first-power laser light to the first light spot, that is, when detecting the area within the preset position range of the wafer 40, the laser emission module 10 emits a low-power laser light, and the low-power laser light becomes a small light spot after passing through the light spot switching module 60, that is, the center area of the wafer is irradiated with a laser light in a low-power and small-spot mode, thereby further preventing the wafer from being damaged due to heat accumulation in the center area of the wafer. When the laser emission module 10 emits a second-power laser light, the light spot switching module 60 is controlled to switch the second-power laser light to a second light spot. That is to say, when detecting an area outside the preset position range of the wafer 40, the laser emission module 10 emits a high-power laser light, and the high-power laser light becomes a large light spot after passing through the light spot switching module 60. That is, the edge area of the wafer is irradiated with laser light in a high-power large-spot mode, which can ensure the detection accuracy of the edge area of the wafer.
[0050] Optionally, the spot area of the first light spot is positively correlated with the power of the first-power laser light, and the spot area of the second light spot is positively correlated with the power of the second-power laser light.
[0051] Specifically, the spot area of the first light spot is positively correlated with the power of the first-power laser light, that is, the first light spot is a small spot, and the power of the first-power laser light is low power. In this way, when scanning the area within the preset position range of the wafer, the wafer will not be damaged due to heat accumulation.
[0052] Specifically, the spot area of the second light spot is positively correlated with the power of the second-power laser light, that is, the second light spot is a large spot and the power of the second-power laser light is high-power. In this way, when scanning the area outside the set position range of the wafer, the detection accuracy of the edge area of the wafer can be guaranteed.
[0053] Exemplarily, the power of the second-power laser light may be twice the power of the first-power laser light, which is not specifically limited in the embodiment of the present invention.
[0054] Optionally, the power P1 of the first-power laser light, the power P2 of the second-power laser light, the spot area S1 of the first light spot and the spot area S2 of the second light spot satisfy: |(P1 / S1)-(P2 / S2)| / (P1 / S1)≤10%; wherein P1, P2, S1 and S2 are all positive numbers.
[0055] Specifically, laser power density can be understood as the energy of laser radiation per unit area per unit time. Furthermore, |(P1 / S1)-(P2 / S2)| / (P1 / S1)≤10%, that is, the power density irradiated within the preset position range of the wafer is approximately equal to the power density irradiated outside the preset position range of the wafer, so that the wafer is not damaged and the detection accuracy of the wafer can be guaranteed to be high.
[0056] Optional, continue to refer to Figure 1 The wafer detection device may further include: a focusing lens module 70; the focusing lens module 70 is located in the optical path between the laser output module 10 and the wafer 40, and is used to focus the laser light and transmit it to the wafer 40, so as to ensure that the laser light incident on the surface of the wafer 40 has good focusing performance, thereby ensuring high detection accuracy.
[0057] Optional, continue to refer to Figure 1 The scattering module 20 includes: a focusing lens unit 201 and a light detection unit 202; the focusing lens unit 201 and the light detection unit 202 are sequentially located in the light path of the scattered light; the light detection unit 202 is electrically connected to the control module 30, and is used to detect the light intensity of the scattered light after being focused by the focusing lens unit 201, and transmit the light intensity to the control module 30.
[0058] Specifically, the laser light is scattered by particles in the wafer 40 to form scattered light, and the scattered light is incident on the focusing lens unit 201 for focusing, and the focused light is incident on the detection unit 202, so that the detection unit 202 can detect the light intensity of the scattered light. The control module 30 is electrically connected to the detection unit 202, and the detection unit 202 can transmit the detected actual scattered light intensity to the control module 30, and the control module 30 determines the defect of the wafer according to the actual scattered light intensity.
[0059] Exemplarily, the detection unit 202 may be a photomultiplier tube, which has high sensitivity to light intensity and can detect small changes in light intensity, thereby improving the detection accuracy of the wafer.
[0060] Optional, Figure 3 This is a schematic diagram of the structure of the second wafer inspection device provided by the embodiment of the present invention, and further reference is made to Figure 2 and Figure 3 The wafer also includes a reflection module 80; the reflection module 80 is used to receive the reflected light after the laser light is reflected by the wafer 40; the control module 30 is also electrically connected to the reflection module 80, and is used to adjust the position of the laser light incident on the wafer 40 according to the position change of the reflected light.
[0061] Specifically, after the laser light is incident on the surface of the wafer 40, it will be reflected on the surface of the wafer 40 to form reflected light. The reflected light can detect the change of the spot position through the reflection module 80, that is, the change of the laser focus can be confirmed by the change of the reflected spot position, so that the laser focus can be calibrated.
[0062] Specifically, the focal position of the laser will be adjusted before inspecting the wafer 40. However, during the inspection process, the laser focus will shift as time changes or the thickness of the wafer at different positions changes. The control module 30 is electrically connected to the reflection module 80, so that the control module 30 can reversely infer the change in the focal position of the laser light based on the change in the position of the reflected light in the reflection module 80, and then perform calibration.
[0063] Specifically, the reflection module 80 includes a reflection unit 801, a collimation unit 802, and a charge coupling unit 803, which are sequentially arranged on the transmission path of the reflected light. Further, the reflected light reflected by the surface of the wafer 40 is reflected by the reflection unit 801 to the collimation unit 802 for collimation, and then incident on the charge coupling unit 803, so that the charge coupling unit 803 detects the change of the spot position.
[0064] Optional, continue to refer to Figure 1 The wafer detection device also includes: a motion module 90; the motion module 90 is located on a side of the wafer 40 away from the laser emission module 10, and is used to drive the wafer to rotate around the center of the wafer 40 and translate along a first direction (the X direction as shown in the figure); the first direction X is the direction from the center of the wafer to the edge of the wafer.
[0065] Specifically, the motion module 90 drives the wafer to rotate around the center of the wafer 40 and translate along the first direction X, so that the detection path of the wafer 40 is spiral, which is conducive to the detection of the wafer.
[0066] Optionally, an embodiment of the present invention may further provide an acousto-optic modulation component in the transmission path of the laser light, and the optical power passing through the acousto-optic modulation component may be regulated by adjusting the voltage of the RF driver, thereby achieving regulation of the laser power incident on the wafer surface.
[0067] In summary, the wafer detection device provided in the embodiment of the present invention adopts a low-power and small-spot laser light when detecting within the preset position range of the wafer; and adopts a high-power and large-spot laser light when detecting outside the preset position range of the wafer, and the laser power density of the two modes is the same. In this way, on the one hand, it can avoid the center area of the wafer from being subjected to laser irradiation for a long time, and the thermal stress generated by heat accumulation can cause wafer damage; on the other hand, it can ensure the detection accuracy.
[0068] Based on the same inventive concept, an embodiment of the present invention further provides a wafer detection method. Figure 4 A schematic diagram of a first wafer inspection method provided by an embodiment of the present invention is shown in FIG. Figure 4 As shown, the wafer inspection method includes:
[0069] S101, determining a theoretical incident position of the laser light on the wafer, and when the theoretical incident position is within a preset position range, controlling the laser emission module to emit a first-power laser light; when the theoretical incident position is outside the preset position range, controlling the laser emission module to emit a second-power laser light.
[0070] For details, please refer to Figure 1 The theoretical incident position of the laser light incident on the surface of the wafer 40 is related to the relative position relationship between the laser output module 10 and the light adjustment module 50, the relative position relationship between the light adjustment module 50 and the wafer 40, and the deflection angle of the light adjustment module 50. The theoretical incident position can be changed by adjusting any of the above parameters.
[0071] Furthermore, since the detection path in the process of detecting the wafer 40 is spiral, that is, starting from the center of the wafer 40, the laser light is used to scan the wafer from the inside to the outside. In the spiral detection path, the linear velocity near the center area of the wafer 40 is slow, and the linear velocity near the edge area of the wafer 40 is fast, so when moving the same path, the detection time of the center area of the wafer 40 is greater than the detection time of the edge area of the wafer. As a comparative example, when the wafer 40 is irradiated with a laser beam of the same power, the central area of the wafer 40 is subjected to a longer laser irradiation, and the thermal stress generated by the accumulation of heat will cause wafer damage. However, in the embodiment of the present invention, the theoretical incident position of the laser light on the wafer 40 is determined before the laser emission module 10 emits the laser, and when the theoretical incident position is within the preset position range, the laser emission module 10 is controlled to emit a first power laser light; when the theoretical incident position is outside the preset position range, the laser emission module 10 is controlled to emit a second power laser light. Specifically, the preset position range can be understood as a position range between a certain position near the center of the wafer 40 and the center of the wafer. It should be noted that the power of the first-power laser light is less than the power of the second-power laser light, so that the control module 30 can control the laser output module 10 to emit a low-power laser light, and then use the low-power laser light to scan the area within the preset position range of the wafer 40; the control module 30 can control the laser output module 10 to emit a high-power laser light, and then use the high-power laser light to scan the area outside the preset position range of the wafer 40, so as to avoid heat accumulation caused by long-term irradiation of the central area of the wafer 40 and causing wafer damage.
[0072] S102, obtaining actual scattered light intensity, and determining defects of the wafer according to the actual scattered light intensity.
[0073] For details, please refer to Figure 1 The scattering module 20 can detect the intensity of the scattered light. The control module 30 can obtain the actual scattered light intensity by being electrically connected to the scattering module 20, and determine the defects of the wafer 40 according to the actual scattered light intensity, such as the size, quantity and distribution of the defects of the wafer.
[0074] The wafer inspection method provided in an embodiment of the present invention uses a low-power laser light to scan the area within the preset position range of the wafer when inspecting the wafer, and uses a high-power laser light to scan the area outside the preset position range of the wafer. This can prevent heat accumulation in the central area of the wafer due to long-term irradiation of the wafer when the same laser is used to irradiate the wafer, thereby preventing damage to the wafer.
[0075] Optional, Figure 5 A schematic diagram of a second wafer inspection method provided by an embodiment of the present invention, Figure 5 Based on the above embodiment, the operations before obtaining the actual scattered light intensity and determining the defect of the wafer according to the actual scattered light intensity are described in detail. Figure 5 As shown, the wafer inspection method includes:
[0076] S201, determining a theoretical incident position of the laser light on the wafer, and when the theoretical incident position is within a preset position range, controlling the laser output module to emit a first-power laser light; when the theoretical incident position is outside the preset position range, controlling the laser output module to emit a second-power laser light.
[0077] S202. When the laser emitting module emits a first-power laser light, the light spot switching module is controlled to switch the first-power laser light to a first light spot. When the laser emitting module emits a second-power laser light, the light spot switching module is controlled to switch the second-power laser light to a second light spot. The light spot area of the first light spot is smaller than the light spot area of the second light spot.
[0078] For details, please refer to Figure 1 , the laser light emitted by the laser emission module 10 can be switched into a large light spot or a small light spot after passing through the light spot switching module 60. The spot area of the first light spot is smaller than the spot area of the second light spot, that is, the first light spot is a small light spot, and the second light spot is a large light spot. When the laser emission module 10 emits a first-power laser light, the light spot switching module 60 is controlled to switch the first-power laser light to the first light spot, that is, when detecting the area within the preset position range of the wafer 40, the laser emission module 10 emits a low-power laser light, and the low-power laser light becomes a small light spot after passing through the light spot switching module 60, that is, the center area of the wafer is irradiated with a laser light in a low-power and small-spot mode, thereby further preventing the wafer from being damaged due to heat accumulation in the center area of the wafer. When the laser emission module 10 emits a second-power laser light, the light spot switching module 60 is controlled to switch the second-power laser light to a second light spot. That is to say, when detecting an area outside the preset position range of the wafer 40, the laser emission module 10 emits a high-power laser light, and the high-power laser light becomes a large light spot after passing through the light spot switching module 60. That is, the edge area of the wafer is irradiated with laser light in a high-power large-spot mode, which can ensure the detection accuracy of the edge area of the wafer.
[0079] S203, obtaining actual scattered light intensity, and determining defects of the wafer according to the actual scattered light intensity.
[0080] The wafer detection method provided by the embodiment of the present invention uses a low-power, small-spot laser light to irradiate the wafer when detecting the center area of the wafer, thereby further ensuring that the center area of the wafer is not damaged due to heat accumulation. When detecting the edge area of the wafer, a high-power, large-spot laser light is used to irradiate the wafer, which can ensure the detection accuracy of the edge area of the wafer.
[0081] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims
1. A wafer inspection device, characterized in that: It includes: a laser emission module, a scattering module and a control module; The laser emitting module is used to emit laser light to the wafer; The scattering module is used to detect the actual scattered light intensity after being scattered by the particles in the wafer; The control module is electrically connected to the scattering module, and is used to obtain the actual scattered light intensity, and determine the defect of the wafer according to the actual scattered light intensity; The control module is also electrically connected to the laser emission module, and is used to determine the theoretical incident position of the laser light on the wafer before the laser emission module emits the laser, and when the theoretical incident position is within the preset position range, control the laser emission module to emit a first-power laser light; when the theoretical incident position is outside the preset position range, control the laser emission module to emit a second-power laser light; Wherein, the wafer detection device further includes: a light spot switching module; The light spot switching module is located in the optical path between the laser emitting module and the wafer; The control module is also electrically connected to the light spot switching module, and is used to control the light spot switching module to switch the first-power laser light to the first light spot when the laser emission module emits the first-power laser light; and to control the light spot switching module to switch the second-power laser light to the second light spot when the laser emission module emits the second-power laser light; the spot area of the first light spot is smaller than the spot area of the second light spot.
2. The wafer inspection device according to claim 1, characterized in that: The spot area of the first light spot is positively correlated with the power of the first-power laser light, and the spot area of the second light spot is positively correlated with the power of the second-power laser light.
3. The wafer inspection device according to claim 2, characterized in that: The power P1 of the first-power laser light, the power P2 of the second-power laser light, the spot area S1 of the first light spot, and the spot area S2 of the second light spot satisfy: |(P1 / S1)-(P2 / S2)| / (P1 / S1)≤10%; Among them, P1, P2, S1 and S2 are all positive numbers.
4. The wafer inspection device according to claim 1, characterized in that: The wafer detection device further includes: a light adjustment module; The light adjustment module is located in the light path between the laser emission module and the wafer, and is used to reflect the laser light to the surface of the wafer at a preset angle; The control module is electrically connected to the light adjustment module, and is used to determine the theoretical incident position according to the relative position relationship between the laser emission module and the light adjustment module, the relative position relationship between the light adjustment module and the wafer, and the deflection angle of the light adjustment module.
5. The wafer inspection device according to claim 1, characterized in that: The scattering module includes: a focusing lens unit and a light detection unit; The focusing lens unit and the light detection unit are sequentially located in the light path of the scattered light; The light detection unit is electrically connected to the control module, and is used to detect the light intensity of the scattered light after being focused by the focusing lens unit, and transmit the light intensity to the control module.
6. The wafer inspection device according to claim 1, characterized in that: The wafer detection device further includes: a reflection module; The reflection module is used to receive the reflected light after the laser light is reflected by the wafer; The control module is also electrically connected to the reflection module, and is used to adjust the position where the laser light is incident on the wafer according to the change in the position of the reflected light.
7. The wafer inspection device according to claim 1, characterized in that: The wafer detection device further includes: a motion module; The motion module is located on a side of the wafer away from the laser emission module, and is used to drive the wafer to rotate around the center of the wafer and translate along a first direction; the first direction is the direction from the center of the wafer to the edge of the wafer.
8. A wafer inspection method, applied to the wafer inspection device according to any one of claims 1 to 7, characterized in that: The wafer detection method comprises: Determine the theoretical incident position of the laser light on the wafer, and when the theoretical incident position is within a preset position range, control the laser emission module to emit a first-power laser light; when the theoretical incident position is outside the preset position range, control the laser emission module to emit a second-power laser light; Acquiring the actual scattered light intensity, and determining the defect of the wafer according to the actual scattered light intensity; Wherein, the laser emission module comprises: a light spot switching module; the light spot switching module is located in the optical path between the laser emission module and the wafer; Before obtaining the actual scattered light intensity and determining the defect of the wafer according to the actual scattered light intensity, the method further includes: When the laser emitting module emits the first-power laser light, controlling the light spot switching module to switch the first-power laser light to a first light spot; When the laser emitting module emits the second-power laser light, the light spot switching module is controlled to switch the second-power laser light to a second light spot; the light spot area of the first light spot is smaller than the light spot area of the second light spot.