Detection device

Abstract

The application provides a detection device, comprising: a structured light source configured to project far-infrared structured light to a sample surface, the structured light being reflected by the sample surface to form signal light; a detector configured to receive the signal light to obtain a detection image; and a processor configured to perform phase analysis on the detection image to detect the sample surface. The detection accuracy of the detection device is improved.

Description

Technical Field

[0001] This utility model relates to the field of detection technology, specifically to a detection device. Background Technology

[0002] In semiconductor manufacturing, to ensure product quality, it is necessary to inspect the product surface to identify defects. Current technology often involves illuminating the product surface with visible light and using a camera to detect the reflected light, thus obtaining an image of the sample surface. The presence of defects is then determined using this image.

[0003] However, when the sample surface is relatively rough, the scattered light from the sample surface is comparable to the scattered light from the defects, resulting in a very low signal-to-noise ratio in the detection image, making it difficult to identify defects. Utility Model Content

[0004] This application provides a testing device to improve the testing accuracy of the testing device.

[0005] This invention provides a detection device, comprising: a structured light source for projecting far-infrared structured light onto a sample surface, wherein the structured light is reflected by the sample surface to form signal light; a detector for receiving the signal light to obtain a detection image; and a processor for performing phase analysis on the detection image to detect the sample surface.

[0006] Optionally, the structured light source is a screen; or, the structured light source includes a projection light source and a grating, wherein the light emitted from the projection light source passes through the grating to form the structured light.

[0007] Optionally, the structured light appears as alternating bright and dark stripes on the sample surface.

[0008] Optionally, it further includes: a support structure for supporting the sample; a first driving structure for driving the structured light source and the support structure to rotate relative to each other; the first driving structure for driving the support structure to rotate around the central axis of the support structure; or, the first driving structure for driving the pattern on the screen to rotate; or, the first driving structure for driving the grating to rotate.

[0009] Optionally, it may also include: a second driving structure, the second driving structure being used to translate the structured light illuminating the sample surface relative to the sample.

[0010] Optionally, the second driving structure is used to translate the structured light illuminating the sample surface relative to the sample along a first direction and / or a second direction; the first direction is not parallel to the stripe extension direction of the structured light on the sample surface, the second direction is not parallel to the stripe extension direction of the structured light on the sample surface, and the second direction is perpendicular to the first direction. Alternatively, the second driving structure is used to translate the sample along a surface parallel to the support structure by moving the support structure, thereby translating the structured light illuminating the sample surface relative to the sample. Or, the second driving structure is used to translate the structured light illuminating the sample surface relative to the sample by moving the grating along an axis parallel to the grating plane. Or, the second driving structure is used to translate the structured light illuminating the sample surface relative to the sample by translating the pattern displayed on the screen.

[0011] Optionally, the processor is configured to acquire detection images at multiple moving positions and obtain the surface slope of the sample based on phase resolution of the multiple detection images. The processor is also configured to acquire curvature data or height data based on the surface slope and obtain defects on the sample surface based on the curvature data or height data.

[0012] Optionally, the processor is configured to acquire detection images at multiple moving positions, including: acquiring multiple detection images at a first moving position when there is a first angle between the fringe extension direction of the structured light on the sample surface and the moving direction of the structured light relative to the sample; acquiring multiple detection images at a second moving position when there is a second angle between the fringe extension direction of the structured light on the sample surface and the moving direction of the structured light relative to the sample; and acquiring multiple detection images at a third moving position when there is a third angle between the fringe extension direction of the structured light on the sample surface and the moving direction of the structured light relative to the sample; wherein the third angle, the second angle, and the first angle are all different.

[0013] Optionally, the wavelength of the structured light is greater than 14 μm.

[0014] Optionally, the sample surface has a rough structure, and the structured light is used to pass through the rough structure to reach the sample surface; the sample includes a ground semiconductor material surface or an unpolished glass surface.

[0015] The technical solution of this utility model has the following beneficial effects:

[0016] In the detection device provided by this utility model, structured light is projected onto the sample surface and modulated by the sample's surface height information to form modulated signal light. The phase of the modulated signal light changes relative to the phase of the structured light. The modulated signal light is detected by the detector to form a detection image. The processor performs phase analysis on the detection image to obtain the height information of the sample surface. Abnormalities in the height information of the sample surface represent the morphology, distortion, or noise location of the sample surface, thus enabling the morphology, distortion, or noise of the sample surface to be resolved. The structured light source is used to project far-infrared structured light onto the sample surface. The wavelength of far-infrared structured light is relatively long. When the detection device detects samples with large rough surfaces, the sample surface is equivalent to specular reflection of the structured light, resulting in a high signal-to-noise ratio in the detection image and improving the detection accuracy for samples with rough surfaces. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of this utility model or the drawings used in the description of the prior art, it is obvious that the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a testing device provided in an embodiment of this utility model;

[0019] Figure 2 for Figure 1 The detection images obtained by the detection equipment. Detailed Implementation

[0020] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0021] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0024] One embodiment of this utility model provides a detection device, see reference. Figure 1 ,include:

[0025] The structured light source 500 is used to project far-infrared structured light onto the surface of the sample 200, and the structured light is reflected by the surface of the sample 200 to form signal light;

[0026] Detector 400 is used to receive the signal light to obtain a detection image;

[0027] A processor is used to perform phase analysis on the detected image to detect the sample surface.

[0028] In this embodiment, after the structured light is projected onto the surface of sample 200, it is modulated by the surface height information of the sample to form a modulated signal light. The phase of the modulated signal light changes relative to the phase of the structured light. The modulated signal light is detected by the detector to form a detection image. The processor performs phase analysis on the detection image to obtain the height information of the sample surface after it is projected onto the surface of sample 200. Anomalies in the height information of the sample surface represent the morphology, distortion, or noise location of the sample surface, thus allowing the morphology, distortion, or noise of the sample surface to be resolved. The structured light source 500 is used to project far-infrared structured light onto the surface of sample 200. The wavelength of far-infrared structured light is relatively long. When the detection device detects a sample 200 with a large rough surface, the surface of sample 200 is equivalent to a specular reflection of the structured light, resulting in a high signal-to-noise ratio of the detection image and improving the detection accuracy of samples 200 with rough surfaces.

[0029] In this embodiment, the sample 200 has a rough surface structure, and the structured light is used to pass through the rough structure to reach the surface of the sample 200; the sample 200 includes a ground semiconductor material surface or an unpolished glass surface.

[0030] Sample 200 can also be an unpolished wafer, unpolished glass, or an unpolished metal layer.

[0031] In this embodiment, the detection device can detect samples 200 with large surface roughness. The wavelength of the structured light is greater than 14 μm, for example, 14 μm, 20 μm, 30 μm or 50 μm.

[0032] In this embodiment, the structured light appears as alternating bright and dark stripes on the surface of sample 200.

[0033] In this embodiment, the detector 400 includes a CCD image sensor.

[0034] In this embodiment, the structured light source 500 is a screen, and the screen displays a pattern that is projected onto the surface of the sample 200. For example, the screen displays a striped pattern and projects it onto the surface of the sample 200, resulting in alternating bright and dark stripes on the surface of the sample 200.

[0035] In other embodiments of this application, the structured light source 500 includes a projection light source and a grating. Light emitted from the projection light source passes through the grating to form structured light. The projection light source can be a point light source or a surface light source. The structured light is formed by modulating the light emitted from the projection light source through the grating, and the structured light appears as alternating bright and dark stripes on the surface of the sample 200.

[0036] In this application, the detection device further includes: a support structure 100 for supporting the sample 200; and a first driving structure (not shown) for driving the structured light source 500 and the support structure 100 to rotate relative to each other, thereby changing the extension direction of the stripe pattern projected by the structured light source 500 onto the surface of the sample 200.

[0037] In one specific embodiment of this application, the first driving structure is used to drive the support structure 100 to rotate around the central axis of the support structure 100, thereby changing the extension direction of the stripe pattern projected by the structured light source 500 onto the surface of the sample 200.

[0038] In another specific embodiment of this application, the first driving structure is used to drive the pattern on the screen to rotate, thereby changing the extension direction of the stripe pattern projected by the structured light source 500 onto the surface of the sample 200.

[0039] In another specific embodiment of this application, the first driving structure is used to drive the grating to rotate, thereby changing the extension direction of the stripe pattern projected by the structured light source 500 onto the surface of the sample 200.

[0040] In this application, the detection device further includes a second driving structure (not shown), which is used to translate the structured light irradiating the surface of the sample 200 relative to the sample 200.

[0041] Specifically, the second driving structure is used to translate the structured light illuminating the surface of the sample 200 relative to the sample 200 along a first direction and / or a second direction; the first direction is not parallel to the fringe extension direction of the structured light on the surface of the sample 200, and the second direction is not parallel to the fringe extension direction of the structured light on the sample surface 200. The second direction is perpendicular to the first direction. Both the second direction and the first direction are parallel to the bearing surface of the bearing structure 100.

[0042] The second driving structure is used to move the support structure 100 to cause the sample 200 to translate along a surface parallel to the support structure 100, thereby causing the structured light illuminating the surface of the sample 200 to translate relative to the sample 200; or, the second driving structure is used to move the grating along an axis parallel to the grating plane to cause the structured light illuminating the surface of the sample 200 to translate relative to the sample 200; or, the second driving structure is used to translate the pattern displayed on the screen to cause the structured light illuminating the surface of the sample 200 to translate relative to the sample 200.

[0043] In this application, the processor is used to acquire detection images at multiple moving positions and obtain the surface slope of the sample based on phase resolution of the multiple detection images. The processor is also used to obtain curvature data or height data based on the surface slope and to obtain defects on the sample surface based on the curvature data or height data.

[0044] In this application, the processor is used to acquire detection images at multiple moving positions, including: the processor is used to acquire multiple detection images at a first moving position when there is a first angle between the fringe extension direction of the structured light on the sample surface and the moving direction of the structured light relative to the sample (see reference). Figure 2 (a)); The processor is configured to acquire multiple detection images of a second moving position at a second angle between the fringe extension direction of the structured light on the sample surface and the moving direction of the structured light relative to the sample (see reference). Figure 2 (b)); The processor is configured to acquire multiple detection images (reference) at a third moving position when the fringe extension direction of the structured light on the sample surface is at a third angle relative to the moving direction of the structured light relative to the sample. Figure 2 (c)); wherein the third angle, the second angle, and the first angle are all different. Detection images acquired at different angles are used to detect the surface of the sample, thus improving detection accuracy.

[0045] After acquiring multiple detection images at a first angle, the fringe extension direction of the structured light is rotated by a preset angle, so that the fringe extension direction of the structured light and the moving direction of the structured light relative to the sample have a second angle; then, multiple detection images at the second angle are acquired; after acquiring multiple detection images at the second angle, the fringe extension direction of the structured light is rotated by a preset angle, so that the fringe extension direction of the structured light and the moving direction of the structured light relative to the sample have a third angle; then, multiple detection images at the third angle are acquired.

[0046] In this embodiment, the detection device further includes an imaging component 300, which is located between the support structure 100 and the detector 400.

[0047] In this embodiment, the imaging component 300 includes a first lens and a second lens. The second lens is located between the first lens and the detector 400. The focal point of the first lens facing the second lens coincides with the focal point of the second lens facing the first lens. By precisely setting the focal point overlap of the two lenses, image quality can be improved and aberrations reduced.

[0048] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A testing device, characterized in that, include: A structured light source is used to project far-infrared structured light onto the sample surface, and the structured light is reflected by the sample surface to form signal light. A detector is used to receive the signal light to obtain a detection image; A processor is used to perform phase analysis on the detected image to detect the sample surface.

2. The detection device according to claim 1, characterized in that, The structured light source is a screen; or, the structured light source includes a projection light source and a grating, and the light emitted from the projection light source passes through the grating to form the structured light.

3. The detection device according to claim 1, characterized in that, The structured light appears as alternating bright and dark stripes on the sample surface.

4. The detection device according to claim 2, characterized in that, Also includes: A support structure for supporting the sample; A first driving structure is used to drive the structured light source and the supporting structure to rotate relative to each other. The first driving structure is used to drive the bearing structure to rotate around the central axis of the bearing structure; Alternatively, the first driving structure is used to drive the pattern on the screen to rotate; Alternatively, the first driving structure is used to drive the grating to rotate.

5. The testing equipment according to any one of claims 1 to 4, characterized in that, Also includes: A second driving structure is used to translate the structured light illuminating the sample surface relative to the sample.

6. The detection device according to claim 5, characterized in that, The second driving structure is used to translate the structured light illuminating the sample surface relative to the sample along a first direction and / or a second direction; the first direction is not parallel to the fringe extension direction of the structured light on the sample surface, the second direction is not parallel to the fringe extension direction of the structured light on the sample surface, and the second direction is perpendicular to the first direction; or... The detection device further includes a support structure for supporting the sample; the second driving structure is used to move the support structure to translate the sample along a surface parallel to the support structure, thereby translating the structured light illuminating the sample surface relative to the sample; or, the structured light source includes a projection light source and a grating, the light emitted from the projection light source passes through the grating to form the structured light, and the second driving structure is used to move the grating along an axis parallel to the plane where the grating is located, thereby translating the structured light illuminating the sample surface relative to the sample; or, the structured light source is a screen; the second driving structure is used to translate the pattern displayed on the screen, thereby translating the structured light illuminating the sample surface relative to the sample.

7. The detection device according to claim 1, characterized in that, The processor is used to acquire detection images at multiple moving positions and obtain the surface slope of the sample based on phase resolution of the multiple detection images. The processor is also used to acquire curvature data or height data based on the surface slope and to obtain defects on the sample surface based on the curvature data or height data.

8. The detection device according to claim 7, characterized in that, The processor is used to acquire detection images of multiple moving locations, including: The processor is used to acquire multiple detection images of a first moving position when there is a first angle between the stripe extension direction of the structured light on the sample surface and the moving direction of the structured light relative to the sample. The processor is used to acquire multiple detection images of a second moving position when there is a second angle between the stripe extension direction of the structured light on the sample surface and the moving direction of the structured light relative to the sample. The processor is used to acquire multiple detection images of a third moving position at a third angle between the stripe extension direction of the structured light on the sample surface and the moving direction of the structured light relative to the sample. The third angle, the second angle, and the first angle are all different.

9. The detection device according to claim 1, characterized in that, The wavelength of the structured light is greater than 14 μm.

10. The detection device according to claim 1, characterized in that, The sample surface has a rough structure, and the structured light is used to pass through the rough structure to reach the sample surface; the sample includes a ground semiconductor material surface or an unpolished glass surface.

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