Light spot positioning carrier, detection device and detection method

Abstract

The invention provides a light spot positioning carrier, a detection device and a detection method.The light spot positioning carrier comprises an objective table and at least one light sensing part, the light sensing part is arranged on the objective table and used for emitting fluorescent light during light irradiation or the contrast ratio of the light sensing part is different when the light sensing part is illuminated and not illuminated for imaging, and the light sensing part is arranged on the objective table. The light sensing part is irradiated by the light to obtain the visible light spot, so that the specific position of the light spot can be known, and the positioning accuracy of the measuring structure is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor equipment technology, and in particular to a light spot positioning carrier, a detection device and a detection method. Background Art

[0002] In the semiconductor measurement process, the ellipsometer obtains the height of the film material by reflecting light. In the prior art, the position of the measuring structure is located by the coordinates of the measuring structure during measurement, and the overlap between the measuring structure and the light spot determines the accuracy of the measurement result. However, the light spot is not visible. During measurement, the measuring structure is found through a microscope. When the measuring structure is moved to the center of the microscope's field of view, it is considered that the detection light spot is located on the measuring structure. The positioning of the structure is completely achieved through coordinates. Therefore, the accuracy of positioning depends on the stability of the machine. At the same time, different measuring structures have different heights, which will result in a deviation between the detection light spot and the target position even though the measuring structure is in the center of the microscope's field of view, causing measurement errors.

[0003] Therefore, it is necessary to provide a new type of light spot positioning carrier, detection device and detection method to solve the above problems existing in the prior art. Summary of the invention

[0004] The object of the present invention is to provide a light spot positioning carrier, a detection device and a detection method to improve the accuracy of measuring structure positioning.

[0005] To achieve the above object, the light spot positioning vehicle of the present invention comprises:

[0006] a stage; and

[0007] At least one photosensitive part is arranged on the stage and is used to emit fluorescence when the detection light is irradiated or the contrast of the imaging of the photosensitive part is different when it is illuminated and when it is not illuminated.

[0008] Optionally, the stage is provided with grooves having the same number as the photosensitive parts, and the photosensitive parts are arranged in the grooves.

[0009] Optionally, the upper surface of the photosensitive portion is flush with the upper surface of the stage.

[0010] Optionally, a transparent protective layer is provided on the photosensitive portion, and an upper surface of the protective layer is flush with an upper surface of the stage.

[0011] Optionally, the size of the photosensitive portion is greater than or equal to the size of a light spot irradiated by the detection light on the photosensitive portion, so that the light spot can be completely located inside the photosensitive portion.

[0012] The present invention also provides a detection device, including the light spot positioning carrier, a moving mechanism, a light source and an imaging unit, wherein the light spot positioning carrier is used to carry a wafer, the light source is arranged on one side of the light spot positioning carrier, and is used to emit detection light, and when the detection light irradiates the photosensitive part, a light spot can be formed on the photosensitive part; the imaging unit can be used to image the light spot and / or the structure to be tested on the wafer; the moving mechanism is arranged below the light spot positioning carrier, and is used to adjust the position of the stage in the vertical direction and / or horizontal direction.

[0013] Optionally, the detection device further includes a height detector, which is arranged on the reflected light path of the detection light and is used to obtain the height of the structure to be measured on the wafer.

[0014] Optionally, the detection device further comprises an image processing unit for marking the light spot in the light spot image taken by the imaging unit; after the light spot is marked, it is located at a fixed position in the field of view of the imaging unit and does not move with the movement of the moving mechanism.

[0015] The present invention also provides a detection method, comprising:

[0016] Providing the detection device;

[0017] The light source is used to irradiate the light sensing part with detection light, thereby forming a visible light spot on the light sensing part and forming reflected light;

[0018] After placing a wafer on the light spot positioning carrier, the wafer has a structure to be measured, and the structure to be measured on the wafer is imaged by the imaging unit;

[0019] Acquire a height H of the structure to be measured on the wafer relative to the light spot positioning carrier;

[0020] The moving mechanism lowers the light spot positioning carrier by a height H of the wafer to achieve the positioning of the light spot.

[0021] Optionally, obtaining a height H of the structure to be measured on the wafer relative to the light spot positioning carrier includes:

[0022] The photosensitive part is photographed by an imaging unit to image the light spot, and the focal length of the imaging unit is adjusted until a clear image is obtained, and the focal length of the imaging unit at this time is recorded as a first focal length, and the first focal length is H1;

[0023] After placing a wafer on the spot positioning carrier, photographing the structure to be measured on the wafer through the imaging unit, adjusting the focal length of the imaging unit until a clear image is obtained, and recording the focal length of the imaging unit at this time as the second focal length, and the second focal length is H2;

[0024] The difference between the first focal length and the second focal length is calculated to obtain a height H of the structure to be measured on the wafer, where H=H1-H2.

[0025] Optionally, the detection device further includes a height detector, which is disposed on a reflected light path of the detection light; and obtaining a height H of the structure to be detected on the wafer relative to the light spot positioning carrier includes:

[0026] The light source emits a detection light to the photosensitive portion, the photosensitive portion reflects the detection light to form a reflected light, the reflected light is received by the height detector, and the height detector records the irradiation position of the reflected light as the first position;

[0027] After placing a wafer on the light spot positioning carrier, the light source emits a detection light to the wafer, the wafer reflects the detection light to form a reflected light, the reflected light is received by the height detector, and the height detector records the position where the reflected light irradiates the height detector as the second position;

[0028] Obtaining a distance between the first position and the second position;

[0029] The height H of the structure to be measured on the wafer is calculated according to the distance through geometric relationship.

[0030] Optionally, the detection device further includes an image processing unit, and the light spot positioning method further includes:

[0031] The light source emits detection light to the photosensitive part to form a visible light spot on the photosensitive part; the imaging unit photographs the light spot on the photosensitive part to form an image of the light spot;

[0032] The image processing unit marks the light spot in the light spot image taken by the imaging unit.

[0033] Optionally, the detection method further comprises moving the light spot mark to the structure to be detected by a moving mechanism to realize visualization of the light spot position.

[0034] The beneficial effects of the present invention are as follows: a photosensitive portion is arranged on a carrier table, and is used to emit fluorescence when irradiated with light or to have different contrast when the image is illuminated and when not illuminated, and the photosensitive portion is illuminated with light to obtain a visible light spot, and the light spot is photographed by an imaging unit to know the specific position of the light spot, and the image photographed by the imaging unit is marked with a light spot by an image processing unit, so that it can be intuitively seen that the light spot is located at the position of the image photographed by the imaging unit, thereby improving the accuracy of positioning the measured structure; the height of the wafer is obtained by detection, and the vertical adjustment unit lowers the stage by the height of the wafer to achieve the positioning of the light spot, correcting the positioning error of the light spot position caused by the difference between wafers of different heights and structures to be measured at different heights on the wafer, thereby improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure of the detection device in some embodiments of the present invention;

[0036] Figure 2 A schematic diagram of an imaging unit capturing an image in some embodiments of the present invention;

[0037] Figure 3 Schematic diagram of detection devices in some other embodiments of the present invention;

[0038] Figure 4 This is a schematic diagram of light irradiation after placing a wafer on the stage;

[0039] Figure 5 The present invention is a flow chart of the detection method in some embodiments of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0041] In view of the problems existing in the prior art, an embodiment of the present invention provides a light spot positioning vehicle. Figure 1 The light spot positioning carrier 100 includes a stage 101 and at least one photosensitive portion 102. Figure 1 Only one photosensitive part 102 is shown. The stage 101 is provided with grooves 1011 having the same number as the photosensitive parts 102 . The photosensitive parts 102 are arranged in the grooves 1011 . The upper surface of the photosensitive parts 102 is flush with the upper surface of the stage 101 .

[0042] In some embodiments, a transparent protective layer is disposed on the upper surface of the photosensitive portion, and the upper surface of the protective layer is flush with the upper surface of the stage.

[0043] In some embodiments, the material of the photosensitive portion is a fluorescent material that can emit fluorescence when irradiated by the detection light, or a material that has different contrast when the photosensitive portion is irradiated with light and when it is not irradiated with light. When light irradiates the photosensitive portion, a visible light spot can be formed on the photosensitive portion. The size of the photosensitive portion is greater than or equal to the size of the light spot to be formed, that is, the light spot is completely located inside the photosensitive portion. Figure 2 As shown, when light irradiates the photosensitive portion, a visible light spot image is formed on the photosensitive portion image.

[0044] In some embodiments, the number of the photosensitive portions is greater than or equal to 1. When the number of the photosensitive portions is 1, preferably, the photosensitive portion is located at the center of the stage. When the number of the photosensitive portions is greater than 1, the photosensitive portions are distributed in an array on the stage.

[0045] In some embodiments, when the number of the photosensitive portions is greater than 1, one of the photosensitive portions is located at the center of the stage, and the remaining photosensitive portions are distributed around the center of the stage.

[0046] The present invention also provides a detection device, referring to Figure 1 , the detection device includes the spot positioning carrier 100, a moving mechanism 200, a light source 300 and an imaging unit 400. The spot positioning carrier is used to carry the wafer to be tested, the light source 300 is arranged on one side of the spot positioning carrier 100, and is used to emit a detection light α, and when the detection light irradiates the photosensitive part, a light spot can be formed on the photosensitive part 102; the imaging unit 400 is used to shoot the light spot; and in some embodiments, the imaging unit 400 can also be used to obtain the height of the structure to be tested on the wafer; the moving mechanism 200 is arranged below the spot positioning carrier 100, and is used to adjust the position of the spot positioning carrier 100 in the vertical direction and / or horizontal direction.

[0047] In some embodiments, the moving mechanism includes a vertical adjustment unit, the vertical adjustment unit includes a vertical slide, a vertical slider and a first drive motor, the vertical slider is slidably connected to the vertical slide, the loading platform is fixedly connected to the vertical slider, and the first drive motor is used to provide power to the vertical slider so that the vertical slider slides along the vertical slide. The vertical adjustment unit can achieve the fixed lifting function of the loading platform, which is a conventional technical means in the field and will not be described in detail here.

[0048] In some embodiments, the moving mechanism further includes a horizontal adjustment unit, which is disposed below the stage and is used to adjust the horizontal position of the stage. The horizontal adjustment unit includes an X-direction slide, an X-direction slide block, a Y-direction slide, and a Y-direction slide block, the Y-direction slide block is slidably connected to the Y-direction slide, the X-direction slide is fixed on the Y-direction slide block, and the X-direction slide is perpendicular to the Y-direction slide, the X-direction slide block is slidably connected to the X-direction slide, and the vertical slide is fixedly connected. The horizontal adjustment unit can realize the movement of the vertical slide in a horizontal plane, which is a conventional technical means in the field and will not be described in detail here.

[0049] Optionally, the detection device further comprises an image processing unit for marking the light spot image captured by the imaging unit. After the light spot is marked, it is located at a fixed position in the field of view of the imaging unit and does not move with the movement of the moving mechanism.

[0050] Figure 3 Schematic diagram of detection devices in some other embodiments of the present invention. Figure 3 and Figure 1 The difference is that the detection device further includes a height detector 500, which is arranged on the reflected light path of the detection light and is used to receive the reflected light after the detection light α irradiates the photosensitive part 102, so as to detect the height of the structure to be measured on the wafer.

[0051] Figure 4 This is a schematic diagram of light irradiation after placing the wafer on the stage. Figure 4, when the wafer 600 is not placed on the stage, the detection light α irradiates the photosensitive part 102, and the light spot formed is located at the foot of the perpendicular between the line a~a' and the upper surface of the photosensitive part 102; after the wafer 600 is placed on the stage, the detection light α remains unchanged, and the light spot formed is located at the foot of the perpendicular between the line b~b' and the upper surface of the wafer 600. It can be seen that the light spot formed by the light α when the wafer is not placed on the stage and the light spot formed by the detection light α when the wafer is placed on the stage are located on different perpendicular lines on the upper surface of the photosensitive part 102; as a result, when the height of the detection structure is different, the detection area in the imaging unit 400 is inconsistent with the actual position of the light spot of the detection light, which leads to detection errors.

[0052] Figure 5 Flow chart of the detection method in some embodiments of the present invention. Figure 5 , the steps of the detection method include:

[0053] S0: providing the detection device;

[0054] S1: emitting detection light to the photosensitive part through the light source, forming a visible light spot on the photosensitive part, and forming reflected light;

[0055] S2: After placing a wafer on the light spot positioning carrier, the wafer has a structure to be measured, and imaging the structure to be measured on the wafer is performed by the imaging unit;

[0056] S3: Obtaining a height H of the structure to be measured on the wafer relative to the light spot positioning carrier;

[0057] S4: The moving structure lowers the light spot positioning carrier by the height H of the wafer to achieve the positioning of the light spot.

[0058] In some embodiments, reference Figure 1 , the step of obtaining a height H of the structure to be measured on the wafer relative to the light spot positioning carrier comprises:

[0059] The photosensitive part is photographed by an imaging unit to image the light spot, and the focal length of the imaging unit is adjusted until a clear image is obtained, and the focal length of the imaging unit at this time is recorded as a first focal length, and the first focal length is H1;

[0060] After placing a wafer on the spot positioning carrier, photographing the structure to be measured on the wafer through the imaging unit, adjusting the focal length of the imaging unit until a clear image is obtained, and recording the focal length of the imaging unit at this time as the second focal length, and the second focal length is H2;

[0061] The difference between the first focal length and the second focal length is calculated to obtain a height H of the structure to be measured on the wafer, where H=H1-H2.

[0062] In some other embodiments, referring to Figure 3 The detection device further includes a height detector, which is disposed on the reflected light path of the detection light; in some embodiments, the height detector is disposed vertically, that is, parallel to the normal of the reflected light; the height detector is used to replace the imaging unit to obtain the height of the wafer, and the height H of the structure to be tested on the wafer relative to the light spot positioning carrier is obtained, including:

[0063] The light source emits a detection light to the photosensitive portion, the photosensitive portion reflects the detection light to form a reflected light, the reflected light is received by the height detector, and the height detector records the irradiation position of the reflected light as the first position;

[0064] After placing a wafer on the light spot positioning carrier, the light source emits a detection light to the wafer, the wafer reflects the detection light to form a reflected light, the reflected light is received by the height detector, and the height detector records the position where the reflected light irradiates the height detector as the second position;

[0065] Obtaining a distance between the first position and the second position;

[0066] The height H of the structure to be measured on the wafer is calculated according to the distance through geometric relationship.

[0067] Reference Figure 3 Line BO is the reflected light of the light α irradiated on the photosensitive part 102, and the irradiation position on the height detector 500 is the first position B, and a light spot is formed at point O at this time; line A-O' is the reflected light of the light α irradiated on the wafer 600, and the irradiation position on the height detector 500 is the second position A, and a light spot is formed at point O' at this time; the distance between the first position B and the second position A is L, and the height of the wafer 600 is H. According to the geometric relationship, it can be calculated that H=0.5L, and the value of L can be detected by the height detector 500, so the value of H can be calculated.

[0068] In some embodiments, the detection device further includes an image processing unit, and the light spot positioning method further includes: emitting detection light to the photosensitive portion by the light source to form a visible light spot on the photosensitive portion; photographing the light spot on the photosensitive portion by the imaging unit to image the light spot; and marking the light spot in the light spot image photographed by the imaging unit by the image processing unit to facilitate determining whether the light spot is located in the middle of the image photographed by the imaging unit. Specifically, a marking line 401 may be drawn along the edge of the light spot to achieve light spot marking, for example Figure 2 . It is also possible to plot the center of the light spot.

[0069] In some embodiments, the detection method includes: moving the light spot mark to the structure to be detected by a moving mechanism to achieve visualization of the light spot position.

[0070] In the present application, the vertical adjustment unit lowers the height of the support platform by the height of the wafer according to the height of the wafer, so that the light spot formed by the detection light α on the wafer 600 overlaps with the light spot formed by the detection light α on the photosensitive part 102, thereby reducing the error caused by the height of the wafer 600.

[0071] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A light spot positioning vehicle, characterized in that: include: Stage; as well as At least one photosensitive part is arranged on the stage and is used to emit fluorescence when the detection light is irradiated or the contrast of the imaging of the photosensitive part is different when it is illuminated and when it is not illuminated.

2. The spot positioning vehicle according to claim 1, characterized in that: The stage is provided with grooves having the same number as the photosensitive parts, and the photosensitive parts are arranged in the grooves.

3. The spot positioning carrier according to claim 1 or 2, characterized in that: The upper surface of the photosensitive portion is flush with the upper surface of the stage.

4. The spot positioning carrier according to claim 1 or 2, characterized in that: A transparent protective layer is provided on the photosensitive portion, and the upper surface of the protective layer is flush with the upper surface of the stage.

5. The spot positioning carrier according to claim 1 or 2, characterized in that: The size of the photosensitive portion is greater than or equal to the size of a light spot irradiated by the detection light on the photosensitive portion, so that the light spot can be completely located inside the photosensitive portion.

6. A detection device, characterized in that: It comprises a spot positioning carrier, a moving mechanism, a light source and an imaging unit as described in any one of claims 1 to 5; the spot positioning carrier is used to carry a wafer; the light source is arranged on one side of the spot positioning carrier, and is used to emit detection light, and when the detection light irradiates the photosensitive part, a light spot can be formed on the photosensitive part; the imaging unit can be used to image the light spot and / or the structure to be measured on the wafer; the moving mechanism is arranged below the spot positioning carrier, and is used to adjust the position of the spot positioning carrier in the vertical direction and / or the horizontal direction.

7. The detection device according to claim 6, characterized in that: It also includes a height detector, which is arranged on the reflected light path of the detection light and is used to obtain the height of the structure to be tested on the wafer.

8. The detection device according to claim 6 or 7, characterized in that: It also includes an image processing unit for marking the light spot in the light spot image taken by the imaging unit. After the light spot is marked, it is located at a fixed position in the field of view of the imaging unit and does not move with the movement of the moving mechanism.

9. A detection method, characterized in that: include: Providing a detection device as described in any one of claims 6 to 8; The light source emits a detection light to the photosensitive part, thereby forming a visible light spot on the photosensitive part and forming a reflected light; Placing a wafer on the light spot positioning carrier, the wafer having a structure to be measured, and imaging the structure to be measured on the wafer by the imaging unit; Acquire a height H of the structure to be measured on the wafer relative to the light spot positioning carrier; The moving mechanism lowers the light spot positioning carrier by a height H of the wafer to achieve the positioning of the light spot.

10. The detection method according to claim 9, characterized in that: The step of obtaining a height H of the structure to be measured on the wafer relative to the light spot positioning carrier comprises: The photosensitive part is photographed by an imaging unit to image the light spot, and the focal length of the imaging unit is adjusted until a clear image is obtained, and the focal length of the imaging unit at this time is recorded as a first focal length, and the first focal length is H1; After placing a wafer on the spot positioning carrier, photographing the structure to be measured on the wafer through the imaging unit, adjusting the focal length of the imaging unit until a clear image is obtained, and recording the focal length of the imaging unit at this time as the second focal length, and the second focal length is H2; The difference between the first focal length and the second focal length is calculated to obtain a height H of the structure to be measured on the wafer, where H=H1-H2.

11. The detection method according to claim 9, characterized in that: The detection device further includes a height detector, which is disposed on the reflected light path of the detection light; the step of obtaining the height H of the structure to be detected on the wafer relative to the light spot positioning carrier includes: The light source emits a detection light to the photosensitive part, the photosensitive part reflects the detection light to form a reflected light, the reflected light is received by the height detector, and the height detector records the position where the reflected light irradiates the height detector as a first position; After placing a wafer on the light spot positioning carrier, the light source emits a detection light to the wafer, the wafer reflects the detection light to form a reflected light, the reflected light is received by the height detector, and the height detector records the position where the reflected light irradiates the height detector as the second position; Obtaining a distance between the first position and the second position; The height H of the structure to be measured on the wafer is calculated according to the distance through geometric relationship.

12. The detection method according to any one of claims 9 to 11, characterized in that: The detection device further includes an image processing unit, and the detection method further includes: The light source emits detection light to the photosensitive part to form a visible light spot on the photosensitive part; the imaging unit photographs the light spot on the photosensitive part to form an image of the light spot; The image processing unit marks the light spot in the light spot image taken by the imaging unit.

13. The detection method according to claim 12, characterized in that: The light spot mark is moved to the structure to be measured by a moving mechanism to realize the visualization of the light spot position.

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