Light path structure for detecting wafer film thickness
By designing an optical path structure, using a mirror to convert horizontal light into vertical light, and filling nitrogen in the closed outer box, the problem of inaccurate thickness of the spectrometer detecting wafer epitaxial film is solved, and the detection accuracy and service life of the equipment are improved.
Patent Information
- Application Number
- CN202422550231.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2034-10-22
AI Technical Summary
In the prior art, when the spectrometer detects the thickness of the wafer epitaxial film, the optical path structure design is not accurate enough, resulting in insufficient detection accuracy and affecting the yield of the semiconductor wafer.
An optical path structure is designed, including a light source, a mirror and an infrared receiver. By setting the reflection angle and focal length of multiple reflectors, horizontal light is converted into vertical light, and nitrogen is charged in the closed outer box to protect the optical path structure and extend the service life of the equipment.
It improves the accuracy and operation flexibility of film thickness detection, extends the service life of the equipment, and ensures the accuracy of the inspection and the stability of the equipment.
Smart Images
Figure CN223295393U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductor manufacturing, in particular to an optical path structure for detecting wafer film thickness. Background Art
[0002] During the semiconductor wafer manufacturing process, different epitaxial film layers are formed, and the thickness of each epitaxial film varies. Epitaxial film thickness is one of the key parameters that influences the physical properties of the wafer. To accurately implement circuit functions, the thickness of each epitaxial film layer formed on the surface of the semiconductor wafer must be precisely controlled to prevent the epitaxial film from being too thick or too thin, causing the semiconductor wafer to not meet the requirements and affecting the yield of the semiconductor wafer. Therefore, in order to monitor the thickness of the epitaxial film, the thickness of the epitaxial film is usually measured after it is formed. If the thickness is abnormal, appropriate corrective measures should be taken immediately.
[0003] Currently, spectrometers are commonly used to measure the thickness of epitaxial films on wafers. In this process, the optical path structure is crucial for ensuring accurate measurement. Therefore, it is necessary to develop and design an optical path structure that can accurately measure wafer film thickness. Utility Model Content
[0004] The utility model aims to provide an optical path structure for detecting wafer film thickness, so as to overcome the deficiencies in the prior art.
[0005] In order to solve the above technical problems, the technical solution of the utility model is: an optical path structure for detecting the film thickness of a wafer, comprising a light source, a reflector 1, a reflector 2, a window, a reflector 3, and an infrared receiver, wherein the reflector 1 and the light source are arranged at both ends of the same horizontal straight line, the window is arranged directly above the wafer to be detected, the reflector 2 and the reflector 1 are arranged side by side, and both are arranged on both sides above the window, and the angle between the reflected light from the reflector 1 to the window and the reflected light from the window to the reflector 2 is an acute angle; the reflector 3 and the reflector 2 are arranged at both ends of the same horizontal straight line, and the infrared receiver is arranged on one side of the reflector 3, and the light emitted by the light source is reflected by the reflector 1, the window, the reflector 2, and the reflector 3 in sequence and then received by the infrared receiver.
[0006] Furthermore, in the above optical path structure for detecting wafer film thickness, an infrared calibration piece is provided between the third reflector and the infrared receiver.
[0007] Furthermore, in the above optical path structure for detecting wafer film thickness, the angle between the reflected light from the first reflector to the window and the reflected light from the window to the second reflector is 5-15°.
[0008] Furthermore, in the above-mentioned optical path structure for detecting wafer film thickness, the focal length of the first reflector and the second reflector is 4-6 inches.
[0009] Furthermore, in the above-mentioned optical path structure for detecting wafer film thickness, the focal length of the third reflector is 2-4 inches.
[0010] Furthermore, the above-mentioned optical path structure for detecting the film thickness of the wafer also includes an outer box, which is a closed rectangular box. The reflector one, reflector two, window, reflector three, infrared receiver, and infrared calibration plate are all arranged in the outer box, and the light source is arranged outside the outer box and connected to the inside of the outer box; a cylinder extending downward is provided at the bottom of the outer box, and the window is fixed to the bottom of the cylinder.
[0011] Furthermore, in the above-mentioned optical path structure for detecting wafer film thickness, the reflector 1, reflector 2, and reflector 3 are all connected to the outer box through an angle adjuster 1 capable of adjusting the angle.
[0012] Furthermore, in the above-mentioned optical path structure for detecting wafer film thickness, the infrared receiver is connected to the outer box through a distance adjuster and an angle adjuster 2, the distance adjuster can adjust the distance between the infrared receiver and the reflector 3, and the angle adjuster can adjust the angle of the infrared receiver.
[0013] Furthermore, in the above optical path structure for detecting wafer film thickness, a drying box is further provided in the outer box, the drying box is provided with a desiccant, and a cover for opening and closing the drying box is provided on the side wall of the outer box.
[0014] Furthermore, in the above-mentioned optical path structure for detecting wafer film thickness, a gas joint is further provided on the side wall of the outer box, and the gas joint is used to fill nitrogen into the outer box.
[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: the optical path structure of the present invention converts horizontally set light into vertically set light, which facilitates the arrangement of the optical path structure in the film thickness detection equipment; and by setting the reflection angle and focal length of multiple reflectors, the detection is accurate and the operation flexibility is good; a closed outer box is also provided, and the outer box is filled with nitrogen and dried, which ensures the normal operation of the optical path structure and extends the service life of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0017] Figure 1 This is a schematic diagram of the external structure of the optical path structure for detecting wafer film thickness according to the present invention;
[0018] Figure 2 This is a schematic diagram of the internal structure of the optical path structure for detecting wafer film thickness in the utility model;
[0019] Figure 3 This is a partial structural diagram of the optical path structure for detecting wafer film thickness according to the present invention;
[0020] In the figure: 1. Light source; 2. Reflector 1; 3. Reflector 2; 4. Window; 5. Reflector 3; 6. Infrared receiver; 7. Infrared calibration plate; 8. Outer box; 9. Cylinder; 10. Angle adjuster 1; 11. Distance adjuster; 12. Angle adjuster 2; 13. Drying box; 14. Box cover; 15. Gas connector. DETAILED DESCRIPTION
[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0022] Example 1
[0023] like Figure 2-3 As shown, an optical path structure for detecting wafer film thickness includes a light source 1, a reflector 2, a reflector 3, a window 4, a reflector 3, and an infrared receiver 6. The reflector 1 2 and the light source 1 are arranged at both ends of the same horizontal line, the window 4 is arranged directly above the wafer to be detected, the reflector 2 3 and the reflector 1 2 are arranged in parallel, and both are arranged on both sides above the window 4, and the angle A between the reflected light from the reflector 1 2 to the window 4 and the reflected light from the window 4 to the reflector 2 3 is an acute angle; the reflector 3 5 and the reflector 2 3 are arranged at both ends of the same horizontal line, the infrared receiver 6 is arranged on the side of the reflector 3-5, and an infrared calibration plate 7 is further provided between the reflector 3 5 and the infrared receiver 6, and the infrared calibration plate 7 is used for infrared calibration light; the light emitted by the light source 1 is reflected by the reflector 1 2, the window 4, the reflector 2 3, and the reflector 3 5 in sequence and then received by the infrared receiver 6. The horizontally arranged light is converted into vertically arranged light by the setting of the reflector 1 2, and then converted into horizontally arranged light by the reflector 3 3, which facilitates the arrangement of the optical path structure in the film thickness detection equipment.
[0024] Among them, Figure 3 As shown, the angle A between the reflected light from the reflector 1 2 to the window 4 and the reflected light from the window 4 to the reflector 2 3 is 5°, which can make the film thickness detection structure accurate.
[0025] In addition, the focal lengths of the reflectors 1 2 and 2 3 are 4 inches, and the focal length of the reflector 3 5 is 2 inches. It should be noted that the embodiment can also adjust the focal lengths of the reflectors according to the current light intensity and the size of the light spot to make the detection structure more accurate.
[0026] Example 2
[0027] like Figure 2-3 As shown, an optical path structure for detecting wafer film thickness includes a light source 1, a reflector 2, a reflector 3, a window 4, a reflector 3, and an infrared receiver 6. The reflector 1 2 and the light source 1 are arranged at both ends of the same horizontal line, the window 4 is arranged directly above the wafer to be detected, the reflector 2 3 and the reflector 1 2 are arranged in parallel, and both are arranged on both sides above the window 4, and the angle A between the reflected light from the reflector 1 2 to the window 4 and the reflected light from the window 4 to the reflector 2 3 is an acute angle; the reflector 3 5 and the reflector 2 3 are arranged at both ends of the same horizontal line, the infrared receiver 6 is arranged on the side of the reflector 3-5, and an infrared calibration plate 7 is further provided between the reflector 3 5 and the infrared receiver 6, and the infrared calibration plate 7 is used for infrared calibration light; the light emitted by the light source 1 is reflected by the reflector 1 2, the window 4, the reflector 2 3, and the reflector 3 5 in sequence and then received by the infrared receiver 6. The horizontally arranged light is converted into vertically arranged light by the setting of the reflector 1 2, and then converted into horizontally arranged light by the reflector 3 3, which facilitates the arrangement of the optical path structure in the film thickness detection equipment.
[0028] Among them, Figure 3 As shown, the angle A between the reflected light from the reflector 1 2 to the window 4 and the reflected light from the window 4 to the reflector 2 3 is 10°, which can make the film thickness detection structure accurate.
[0029] In addition, the focal lengths of the reflectors 1 2 and 2 3 are 5 inches, and the focal length of the reflector 3 5 is 3 inches. This embodiment can also adjust the focal lengths of the reflectors according to the current light intensity and the size of the light spot, making the detection structure more accurate.
[0030] Example 3
[0031] Based on the structure of Example 1 or Example 2, as Figure 1 、 2 As shown, it also includes an outer box 8, which is a closed rectangular box. The reflector 1 2, reflector 2 3, window 4, reflector 3 5, infrared receiver 6, and infrared calibration plate 7 are all arranged in the outer box 8. The light source 1 is arranged outside the outer box 8 and is connected to the outer box 8; a downward extending cylinder 8 is provided at the bottom of the outer box 8, and the window 4 is fixed to the bottom of the cylinder 9.
[0032] Among them, Figure 2As shown, reflector 1 2, reflector 2 3, and reflector 3 5 are all connected to the outer box 8 via an adjustable angle adjuster 10. By adjusting angle adjuster 1, the angle of reflected light from reflector 1 2, reflector 2 3, and reflector 3 5 can be adjusted. The infrared receiver 6 is connected to the outer box 8 via a distance adjuster 11 and an angle adjuster 2 12. The distance adjuster 11 adjusts the distance between the infrared receiver 6 and reflector 3 5, while the angle adjuster 12 adjusts the angle of the infrared receiver 6. This improves the operational flexibility of the equipment and ensures detection accuracy.
[0033] In addition, if Figure 1 、 2 As shown, the outer box 8 also houses a drying box 13 filled with desiccant. A lid 14 is installed on the side wall of the outer box 8 to facilitate desiccant replacement. A gas connection 15 is also located on the side wall of the outer box 8 for nitrogen filling. The drying box and nitrogen filling system protect the components within the outer box, ensuring proper operation of the optical path structure and extending the service life of the equipment.
[0034] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.
[0035] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.
Claims
1. An optical path structure for detecting wafer film thickness, characterized by: It includes a light source, a reflector 1, a reflector 2, a window, a reflector 3, and an infrared receiver. The reflector 1 and the light source are arranged at both ends of the same horizontal line, the window is arranged directly above the wafer to be detected, the reflector 2 and the reflector 1 are arranged in parallel, and both are arranged on both sides above the window, and the angle between the reflected light from the reflector 1 to the window and the reflected light from the window to the reflector 2 is an acute angle; the reflector 3 and the reflector 2 are arranged at both ends of the same horizontal line, and the infrared receiver is arranged on one side of the reflector 3. The light emitted by the light source is reflected by the reflector 1, the window, the reflector 2, and the reflector 3 in sequence and then received by the infrared receiver.
2. The optical path structure for detecting wafer film thickness according to claim 1, characterized in that: An infrared calibration piece is also provided between the reflector three and the infrared receiver.
3. The optical path structure for detecting wafer film thickness according to claim 1, characterized in that: The angle between the reflected light from the first reflector to the window and the reflected light from the window to the second reflector is 5-15°.
4. The optical path structure for detecting wafer film thickness according to claim 1, characterized in that: The focal lengths of the first reflector and the second reflector are 4-6 inches.
5. The optical path structure for detecting wafer film thickness according to claim 1 or 4, characterized in that: The focal length of the reflector 3 is 2-4 inches.
6. The optical path structure for detecting wafer film thickness according to claim 2, characterized in that: It also includes an outer box, which is a closed rectangular box. The reflector 1, reflector 2, window, reflector 3, infrared receiver, and infrared calibration plate are all arranged in the outer box. The light source is arranged outside the outer box and connected to the inside of the outer box. A cylinder extending downward is provided at the bottom of the outer box, and the window is fixed to the bottom of the cylinder.
7. The optical path structure for detecting wafer film thickness according to claim 6, characterized in that: The first reflector, the second reflector and the third reflector are all connected to the outer box via an angle adjuster 1 capable of adjusting the angle.
8. The optical path structure for detecting wafer film thickness according to claim 6, characterized in that: The infrared receiver is connected to the outer box through a distance adjuster and a second angle adjuster. The distance adjuster can adjust the distance between the infrared receiver and the third reflector, and the angle adjuster can adjust the angle of the infrared receiver.
9. The optical path structure for detecting wafer film thickness according to claim 6, characterized in that: A drying box is further provided in the outer box. The drying box is provided with a desiccant. A box cover for opening and closing the drying box is provided on the side wall of the outer box.
10. The optical path structure for detecting wafer film thickness according to claim 6 or 9, characterized in that: A gas joint is also provided on the side wall of the outer box, and the gas joint is used to fill nitrogen into the outer box.