Optical detection device

Abstract

The optical detection device provided by the embodiment of the invention comprises a light source used for generating or introducing a detection light beam; the shaping lens group is connected with a light path of the light source and is used for enabling the short side of the detection light beam to irradiate a to-be-detected piece; and the detector is used for receiving the reflected light beam of the to-be-detected piece. According to the optical detection device, after the shaping lens group is arranged to shape the detection light beam from the light source, the detection light beam irradiates a to-be-detected piece in a short-edge irradiation mode, and therefore the phenomenon that emergent light generated by a non-to-be-detected surface and reflected light generated by a to-be-detected surface are overlapped is avoided; therefore, the detector of the optical detection device provided by the embodiment of the invention can only receive the reflected light, so that the interference of emergent light on the detector is avoided; therefore, according to the optical detection device provided by the embodiment of the invention, the interference of the non-to-be-detected surface of the to-be-detected piece on the detection result is eliminated, and the quality of the detection result is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor detection, and particularly to an optical detection device. Background Art

[0002] In the technical field of semiconductor detection, generally, an optical detection device is used to detect defects on the surface of a semiconductor. The light source in the optical detection device emits a light beam along a preset emission direction, and the light beam has a certain cross-sectional area in a plane perpendicular to the emission direction. When detecting a test piece made of a wide-bandgap semiconductor material, when the light beam irradiates the test piece, since the test piece is made of a wide-bandgap semiconductor material, part of the light beam will transmit through the test surface of the test piece, and the other part of the light beam will be reflected on the test surface. The transmitted light beam will be reflected on the non-test surface of the test piece. The non-detection light beam reflected by the non-test surface returns to the test surface and exits from the test surface. For example, referring to Figure 1 the optical path schematic diagram shown, the incident light L irradiates the semiconductor surface, and the incident light L has a width W. After the incident light L irradiates the semiconductor surface, part of it becomes the reflected light R1, and the reflected light R1 also has a width W; a part of the incident light L will transmit through the semiconductor surface and form the transmitted light F. The transmitted light F will be reflected on the lower surface of the semiconductor and exit from the semiconductor surface to form the outgoing light R2. In Figure 1 the optical path shown, it is obvious that due to the width W of the incident light L and the fact that both the upper and lower surfaces of the semiconductor reflect light, there is partial overlap between the reflected light R1 and the outgoing light R2. Therefore, if the upper surface of the semiconductor is the test surface, then the reflected light R1 is the light beam reflected by the test surface, and the outgoing light R2 formed after being reflected by the lower surface of the semiconductor is the non-detection light beam. After the detector of the optical detection device simultaneously receives the reflected light R1 and the outgoing light R2, the outgoing light R2 will affect the reflected light R1 and interfere with the detection or imaging of the reflected light R1 by the detector. Therefore, when the detector simultaneously receives the reflected light from the test surface of the semiconductor and the reflected light from the non-test surface, the reflected light from the non-test surface will interfere with the detection result of the optical detection device. Summary of the Invention

[0003] To solve the technical problem that in an optical detection device, its detector will simultaneously receive the reflected light from the test surface and the reflected light from the non-test surface, thereby interfering with the detection structure of the optical detection device; an embodiment of the present invention provides an optical detection device. The optical detection device provided by the embodiment of the present invention realizes irradiating the short side of the detection light beam on the test piece by setting a shaping mirror group, thereby avoiding the overlap between the reflected light from the non-test surface and the reflected light from the test surface of the test piece, thus interfering with the technical problem of the detector imaging detection, and therefore improving the detection effect of the optical detection device.

[0004] An optical detection device provided by an embodiment of the present invention includes: a light source for generating or introducing a detection beam; a shaping mirror group optically connected to the light source and configured to irradiate a short side of the detection beam onto a workpiece to be measured; and a detector for receiving a reflected beam of the workpiece to be measured.

[0005] In an embodiment of the present invention, the optical detection device further includes: an angle adjustment mirror group optically connected to the shaping mirror group and configured to adjust an angle at which the detection beam irradiates the workpiece to be measured.

[0006] In an embodiment of the present invention, the angle adjustment mirror group includes: a fast steering mirror unit optically connected to the shaping mirror group and electrically connected to the detector, and the fast steering mirror unit is configured to control an angle at which the detection beam irradiates the workpiece to be measured according to a detection result of the detector.

[0007] In an embodiment of the present invention, the optical detection device further includes: a stage for carrying the workpiece to be measured; a height adjustment assembly connected to the stage and electrically connected to the detector, and the height adjustment assembly is configured to adjust a height of the stage according to a detection result of the detector.

[0008] In an embodiment of the present invention, the shaping mirror group includes: a linear light conversion unit optically connected to the light source and configured to shape the detection beam into a linear detection beam.

[0009] In an embodiment of the present invention, the shaping mirror group further includes a rotation adjustment unit connected to the linear light conversion unit and configured to adjust an extension direction of the linear detection beam.

[0010] In an embodiment of the present invention, the shaping mirror group further includes: a mirror group housing, the linear light conversion unit is connected to the mirror group housing; a collimating lens movably connected to the mirror group housing and optically connected to the linear light conversion unit.

[0011] In an embodiment of the present invention, the optical detection device further includes: a beam reduction mirror unit optically connected to the detector and configured to shape the reflected beam.

[0012] In an embodiment of the present invention, the optical detection device further includes: a normal incidence optical mirror group optically connected to the light source and configured to make the detection beam normally incident on the workpiece to be measured; and an imaging mirror group for receiving scattered light from the workpiece to be measured.

[0013] In an embodiment of the present invention, the optical detection device further includes a stage for carrying the workpiece to be measured; the imaging mirror group includes a plurality of cameras oppositely arranged in different directions of the stage.

[0014] The above technical solution provided by the embodiments of the present invention has at least the following beneficial effects:

[0015] After the optical detection device shapes the detection beam from the light source through the shaping mirror group, the detection beam irradiates the workpiece to be measured in the form of short-side irradiation, thereby avoiding the overlap between the outgoing light generated by the non-workpiece surface to be measured and the reflected light generated by the workpiece surface to be measured; Therefore, the detector of the optical detection device provided by the embodiments of the present invention can only receive the reflected light, thus avoiding the interference of the outgoing light on the detector; Therefore, the optical detection device provided by the embodiments of the present invention eliminates the interference of the non-workpiece surface to be measured of the workpiece on the detection result and improves the quality of the detection result. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic diagram of the optical path of the detection light at the workpiece to be measured in the existing optical detection device.

[0018] Figure 2 It is a schematic diagram of the optical path of the detection light at the workpiece to be measured of the optical detection device provided by the embodiments of the present invention.

[0019] Figure 3 It is a schematic three-dimensional structure diagram of the optical detection device provided by the embodiments of the present invention.

[0020] Figure 4 is Figure 3 A schematic diagram of the optical path structure from the shaping mirror group shown to the detector.

[0021] Figure 5 is Figure 3 A schematic three-dimensional structure diagram of the stage and the height adjustment assembly shown.

[0022] Figure 6 is Figure 4 A schematic diagram of the optical structure of the linear light conversion unit shown.

[0023] Figure 7 is Figure 3 A schematic three-dimensional structure diagram at the rotation adjustment unit shown. Detailed Embodiments

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0025] It should be noted that the terms "first", "second", "one end", etc. in the specification and claims of the present invention are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, products, or devices.

[0026] See Figure 3 , an optical detection device 10 provided by an embodiment of the present invention includes: a light source 12, a shaping mirror group 14, and a detector 16. The light source 12 is used to generate or introduce a detection beam. The shaping mirror group 14 is optically connected to the light source 12 and is used to irradiate the short side of the detection beam on the workpiece to be measured. The detector 16 is used to receive the reflected beam of the workpiece to be measured.

[0027] In the optical detection device 10 provided by the embodiment of the present invention, the shaping mirror group 14 shapes the detection beam from the light source 12. Specifically, the detection beam from the light source 12 has a cross-sectional area in a plane perpendicular to the propagation direction, and thus has a shape in the plane, such as a rectangle, a circle, an ellipse, etc., and may also be an irregular shape. The shaping mirror group 14 changes the shape of the detection beam in the plane. The shape of the detection beam after the shape change becomes a rectangle or a polygon similar to a rectangle. Taking a rectangle as an example, the length of the short side of the rectangle is much smaller than the length of the long side. For example, the difference between the length of the long side and the length of the short side is more than one order of magnitude. At this time, the cross-sectional shape of the detection beam in the plane can be approximated as a line. In the optical detection device 10 provided by the embodiment of the present invention, after the detection beam is shaped by the shaping mirror group 14 and irradiates on the workpiece to be measured, see Figure 2, the propagation direction of the incident light L of the detection beam and the propagation direction of the reflected light R1 on the detection plane of the workpiece to be measured form an optical path plane. Moreover, the length direction of the long side of the detection beam is perpendicular to the optical path plane, and the length direction of the short side of the detection beam is parallel to or lies in the optical path plane, that is, the detection beam irradiates the workpiece to be measured in the form of short-side irradiation. In Figure 2 In the optical path diagram shown, a part of the incident light L of the beam to be measured enters the workpiece to be measured, and thus transmitted light F is formed. The transmitted light F is reflected on the non-measured surface of the workpiece to be measured, returns and exits from the measured surface, and thus outgoing light R2 is formed. In Figure 2 It can be clearly seen that the reflected light R1 and the outgoing light R2 do not overlap due to short-side irradiation, that is, there is a gap between the reflected light R1 and the outgoing light R2. As Figure 1 shown, the length of the long side of the incident light L is W, and the length direction of the long side is parallel to or lies in the plane formed by the propagation direction of the incident light L and the propagation direction of the reflected light R1, that is, Figure 1 the situation shown is the long-side irradiation mode of the detection beam.

[0028] In summary, after the optical detection device 10 provided by the embodiment of the present invention shapes the detection beam from the light source by setting the shaping mirror group 14, the detection beam irradiates the workpiece to be measured in the form of short-side irradiation, and thus avoids the phenomenon that the outgoing light R2 generated by the non-measured surface and the reflected light R1 generated by the measured surface overlap as shown in Figure 2 shown. Therefore, the detector 16 of the optical detection device 10 provided by the embodiment of the present invention can only receive the reflected light R1, thereby avoiding the interference of the outgoing light R2 on the detector 16. Therefore, the optical detection device 10 provided by the embodiment of the present invention eliminates the interference of the non-measured surface of the workpiece to be measured on the detection result and improves the quality of the detection result.

[0029] Specifically, the light source 12 can be, for example, a laser generator, or an optical mirror group for introducing external light, or the light source 12 can also be a combination of a laser generator and an optical mirror group, etc. The detector 16 is, for example, a CCD lens, etc. The workpiece to be measured is, for example, a special transparent wafer such as sapphire.

[0030] Furthermore, referring to Figure 4 , the optical detection device 10 further includes an angle adjustment mirror group 18. The angle adjustment mirror group 18 is optically connected to the shaping mirror group 14 and is used to adjust the angle at which the detection beam irradiates the workpiece to be measured. Since the optical detection device 10 uses the short-side irradiation method to detect the workpiece to be measured, therefore, if the height of the workpiece to be measured or the flatness of the measured surface of the workpiece to be measured changes slightly, it will cause such asFigure 2 The exit angle of the reflected light R1 shown changes, resulting in a large optical path deviation, causing the reflected light R1 to be unable to reach the detector 16. Therefore, the setting of the angle adjustment mirror group 18 allows the user to Figure 2 adjust the incident angle of the incident light L of the beam to be measured shown, thereby adjusting the exit angle of the reflected light R1. Therefore, the setting of the angle adjustment mirror group 18 allows the user to adjust the exit angle of the reflected light R1 so that it can be received by the detector 16.

[0031] Furthermore, referring to Figure 4 the angle adjustment mirror group 18 includes a fast steering mirror unit 182. The fast steering mirror unit 182 is optically connected to the shaping mirror group 14 and electrically connected to the detector 16. The fast steering mirror unit 182 is used to control the angle at which the detection beam irradiates the workpiece to be measured according to the detection result of the detector 16. The fast steering mirror unit 182 includes, for example, a driving element and a reflecting mirror, and the driving unit can drive the reflecting mirror to rotate at a high frequency. On this basis, the fast steering mirror unit 182 is electrically connected to the detector 16. The detection result of the detector 16 is fed back to the fast steering mirror unit 182. The fast steering mirror unit 182 responds to the detection result from the detector 16 and adjusts the incident angle of the detection beam relative to the workpiece to be measured, thereby realizing the closed-loop control of the fast steering mirror unit 182 and the detector 16.

[0032] Specifically, the fast steering mirror unit 182 may, for example, include an integrated circuit with signal processing functions, or the fast steering mirror unit 182 and the detector 16 may be electrically connected through a processor pre-set with a control program, or through a computer that can be manually operated. Other optical units such as a reflecting mirror 184 may also be included in the angle adjustment mirror group 18. The reflection angle of the reflecting mirror 184 can also be adjusted, for example, so that the detection beam perpendicularly reaches the fast steering mirror unit 182.

[0033] In addition, referring to Figure 5 , the optical detection device 10 further includes a stage 11 and a height adjustment component 13. The stage 11 is used to carry the workpiece to be measured. The height adjustment component 13 is connected to the stage 11 and electrically connected to the detector 16. The height adjustment component 13 is used to adjust the height of the stage 11 according to the detection result of the detector 16. Combining the above content, since in the optical detection device 10 provided in the embodiment of the present invention, the short-side irradiation method is adopted to detect the workpiece to be measured, and therefore, there are relatively high-precision requirements for the angle at which the detection beam irradiates the workpiece to be measured. And the angle at which the detection beam irradiates the workpiece to be measured is related to the incident angle of the detection beam and the placement position of the workpiece to be measured. AsFigure 5 The optical detection device 10 shown controls the height of the stage 11 by providing a height adjustment assembly 13 connected to the stage 11, thereby controlling the position of the workpiece to be measured, and thus adjusting the angle at which the detection beam irradiates the workpiece to be measured.

[0034] Specifically, the height adjustment assembly 13 may be, for example, an electric lifting table for optics. This embodiment does not exclude the height adjustment assembly 13 from having movement adjustment methods such as rotation, translation, or tilting on the basis of height adjustment. The optical detection device 10 provided by the embodiment of the present invention may separately include the angle adjustment assembly 18, or the height adjustment assembly 13, or include both the angle adjustment assembly 18 and the height adjustment assembly 13 at the same time.

[0035] Furthermore, referring to Figure 4 and Figure 6 , the shaping lens group 14 includes a linear light conversion unit 142. The linear light conversion unit 142 is optically connected to the light source 12 and is used to shape the detection beam into a linear detection beam. The linear light conversion unit 142 can shape the detection beam into the approximately linear beam described above. Since the detection beam shaped by the linear light conversion unit 142 may be spherical light, the shaping lens group 14 may also, for example, include a collimating lens unit 144, and the collimating lens unit 144 can shape the detection beam into parallel light. Specifically, the linear light conversion unit 142 may be, for example, a Powell prism, and the shaping effect of the Powell prism on the beam is as Figure 6 shown.

[0036] Even further, referring to Figure 3 and Figure 4 , the shaping lens group 14 further includes a lens group housing 148. The linear light conversion unit 142 is connected to the lens group housing 148. The collimating lens unit 144 includes a collimating lens 146. The collimating lens 146 is movably connected to the lens group housing 148, and the collimating lens 146 is optically connected to the linear light conversion unit 142. Since the detection beam will propagate outward in the form of spherical light after passing through the linear light conversion unit 142, the distance between the collimating lens 146 and the linear light conversion unit 142 will affect the beam size and energy density of the detection beam after passing through the collimating lens 146. Therefore, the movable connection between the collimating lens 146 and the lens group housing 148 can change the distance between the collimating lens 146 and the linear light conversion unit 142, thereby adjusting the beam size and energy density of the detection beam after passing through the collimating lens 146.

[0037] In addition, the collimating lens 146 can also be movably connected to the lens group housing 148 through a rotating mechanism, or the rotating mechanism is provided on the lens group housing 148. Through the rotating mechanism, the collimating lens 146 can be rotated. Therefore, when the transposed lens 146 is, for example, a fast-axis collimating mirror, the fast-axis collimating mirror can be adjusted by rotation. The collimating mirror unit 144 can also include other optical elements. For example, the collimating mirror unit 144 further includes a lens 149 as shown in Figure 4 . Among them, the collimating lens 146 and the lens 149 form, for example, a doublet lens system. The collimating lens 146 is, for example, a cylindrical mirror that collimates in the fast-axis direction, and the lens 149 is correspondingly a cylindrical mirror that collimates in the slow-axis direction, or the lens 149 is a spherical mirror with a collimating function.

[0038] See Figure 7 . The shaping lens group 14 further includes a rotation adjustment unit 141. The rotation adjustment unit 141 is connected to the linear light conversion unit 142 and is used to adjust the extension direction of the linear detection beam. Since the optical detection device 10 provided in the embodiment of the present invention irradiates the workpiece to be measured in a manner of irradiating with the short side, by setting the rotation adjustment unit 141, the user can adjust and rotate the linear light conversion unit 142, so as to ensure that the short-side irradiation manner is achieved. The extension direction of the detection beam is the long-side length direction of the detection beam.

[0039] Furthermore, see Figure 4 . The optical detection device 10 further includes a beam reducing lens unit 15. The beam reducing lens unit 15 is optically connected to the detector 16 and is used to shape the reflected beam.

[0040] Furthermore, see Figure 3, the optical detection device 10 further includes a normal-incidence optical lens group 19 and an imaging lens group. The normal-incidence optical lens group 19 is optically connected to the light source 12 and is configured to make the detection beam normally incident on the workpiece to be measured. The imaging lens group is configured to receive the scattered light from the workpiece to be measured. The light source 12 may include, for example, a dual-channel laser, or include a beam splitter and direct the detection beam to the shaping lens group 14 and the normal-incidence optical lens group 19 through the beam splitter respectively, or the light source 12 includes adjustable prisms, lenses, etc. to adjust the propagation direction of the detection beam so that the detection beam reaches the shaping lens group 14 or the normal-incidence optical lens group 19. The normal-incidence optical lens group 19 can make the detection beam normally incident on the workpiece to be measured. The imaging lens group can capture the light scattered by the workpiece to be measured and thus perform imaging detection on the workpiece to be measured. Moreover, on the basis of using the detector 16 to detect the reflected light that is irradiated on the workpiece to be measured from the short side and reflected by the workpiece to be measured, the optical detection device 10 also captures the scattered light from the workpiece to be measured through the imaging lens group. Both the imaging lens group and the detector 16 can perform imaging detection on the workpiece to be measured. For example, detect scratches or various other defects on the surface of a wafer. Specifically, the normal-incidence optical lens group 19 may include, for example, optical elements such as a collimating lens and a mirror.

[0041] Furthermore, the optical detection device 10 further includes a stage 11. The stage 11 is configured to carry the workpiece to be measured. The imaging lens group includes a plurality of cameras 172, and the plurality of cameras 172 are oppositely arranged in different directions of the stage 11. Therefore, the imaging lens group can capture the scattered light generated by the workpiece to be measured disposed on the stage 11 in different directions through the plurality of cameras 172. The camera 172 is, for example, a TDI camera. The TDI camera is suitable for high-speed imaging in a low-light environment and can achieve continuous inspection of the workpiece to be measured during movement.

[0042] In addition, the optical detection device 10 is not limited to the short-side irradiation method, and the detection beam can also irradiate the component to be measured by the long-side irradiation method. The optical detection device 10 can be provided with a plurality of optical systems arranged separately, where one optical system irradiates the component to be measured by the short-side irradiation method; another optical system irradiates the component to be measured by the long-side irradiation method. Or in the optical system capable of short-side irradiation, the linear light conversion unit 142 is rotated by the rotation adjustment unit 141 to achieve irradiating the component to be measured by the long-side irradiation method. Whether it is the long-side irradiation or the short-side irradiation method, the detection beam is incident at a certain inclination angle with respect to the surface to be measured of the component to be measured. Therefore, the other optical system in the optical detection device 10 can also irradiate the component to be measured in a manner perpendicular to the surface to be measured of the component to be measured. When the detection beam is perpendicularly incident on the component to be measured, the plurality of cameras 172 can capture the scattered light caused by the component to be measured, and thereby perform imaging detection on the component to be measured.

[0043] In addition, it can be understood that the foregoing embodiments are only exemplary descriptions of the present invention. On the premise that the technical features do not conflict, are fixed without contradiction, and do not violate the invention purpose of the present invention, the technical solutions of each embodiment can be arbitrarily combined and used in combination.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. An optical detection device (10), characterized in that, Comprising: A light source (12) for generating or introducing a detection beam; A shaping mirror group (14) optically connected to the light source (12) and configured to irradiate a short side of the detection beam onto the workpiece to be measured; A detector (16) for receiving the reflected beam of the workpiece to be measured.

2. The optical detection device (10) according to claim 1, wherein Further comprising: An angle adjustment mirror group (18) optically connected to the shaping mirror group (14) and configured to adjust the angle at which the detection beam irradiates the workpiece to be measured.

3. The optical detection device (10) according to claim 2, characterized in that, The angle adjustment mirror group (18) comprises: A fast steering mirror unit (182) optically connected to the shaping mirror group (14) and electrically connected to the detector (16), the fast steering mirror unit (182) being configured to control the angle at which the detection beam irradiates the workpiece to be measured according to the detection result of the detector (16).

4. The optical detection device (10) according to claim 1, characterized in that, Further comprising: A stage (11) for carrying the workpiece to be measured; A height adjustment assembly (13) connected to the stage (11) and electrically connected to the detector (16), the height adjustment assembly (13) being configured to adjust the height of the stage (11) according to the detection result of the detector (16).

5. The optical detection device (10) according to claim 1, characterized in that, The shaping mirror group (14) comprises: A linear light conversion unit (142) optically connected to the light source (12) and configured to shape the detection beam into a linear detection beam.

6. The optical detection device (10) according to claim 5, characterized in that, The shaping mirror group (14) further comprises a rotation adjustment unit (141) connected to the linear light conversion unit (142) and configured to adjust the extension direction of the linear detection beam.

7. The optical detection device (10) according to claim 5, characterized in that, The shaping mirror group (14) further comprises: A mirror group housing (148) to which the linear light conversion unit (142) is connected; A collimating lens (146) movably connected to the mirror group housing (148) and optically connected to the linear light conversion unit (142).

8. The optical detection device (10) according to claim 1, characterized in that, Further comprising: A beam reducing mirror unit (15) optically connected to the detector (16) and configured to shape the reflected beam.

9. The optical detection device (10) according to claim 1, characterized in that, Further comprising: A normal incidence optical mirror group (19) optically connected to the light source (12) and configured to make the detection beam normally incident on the workpiece to be measured; An imaging mirror group for receiving the scattered light from the workpiece to be measured.

10. The optical detection device (10) according to claim 9, characterized in that, Further comprising a stage (11) for carrying the workpiece to be measured; The imaging mirror group comprises a plurality of cameras (172) oppositely arranged in different directions of the stage (11).

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