Device for detecting doping uniformity of silicon carbide wafer
By combining a light source, a testing fixture, a polarizing component, and a photosensitive component, the problems of high cost, low accuracy, and insufficient coverage in the detection of doping uniformity of silicon carbide wafers in the prior art are solved. This achieves low-cost, high-precision non-destructive testing and can provide quantitative feedback on small-area doping anomalies.
Patent Information
- Application Number
- CN202520160926.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-01-23
AI Technical Summary
Existing technologies are difficult to use in a low-cost, non-destructive manner to detect the doping uniformity of silicon carbide wafers, and cannot cover the entire wafer surface. The detection results are also highly subjective or lack precision.
By employing a combination of light source, detection fixture, polarizing component, and photosensitive component, the transmittance of different locations on the silicon carbide wafer is calculated to determine the doping uniformity through beam incident, filtering, and transmittance detection. The polarizing component is used to avoid the influence of scattered light, and the photosensitive component array detects the entire wafer surface.
It enables low-cost, non-destructive detection of doping uniformity across the entire silicon carbide wafer surface, with high detection accuracy, capable of detecting doping anomalies with an area smaller than 1 mm², and the results are quantifiable.
Smart Images
Figure CN223897312U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of silicon carbide wafer inspection technology, and in particular to a device for detecting the doping uniformity of silicon carbide wafers. Background Technology
[0002] Silicon carbide (SiC) plays a crucial role in the development of third-generation semiconductors. Due to its excellent physical properties, such as low impedance, high switching frequency, better thermal conductivity, and higher breakdown electric field, SiC can be used in high-voltage environments (>1200V). Compared to silicon, SiC offers better performance and a wider range of power supply applications. There has been consistently strong demand for SiC wafers in the global power market.
[0003] Optimizing the detection technology for doping uniformity of silicon carbide wafers is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content
[0004] In view of the above problems, this application provides a device for detecting the doping uniformity of silicon carbide wafers. The specific solution is as follows:
[0005] The first aspect of this application provides a device for detecting the doping uniformity of a silicon carbide wafer, the device comprising: a light source, a detection fixture, a polarizing component, a photosensitive component, and a processing component; the silicon carbide wafer to be detected is mounted on the detection fixture;
[0006] The light source is used to emit a light beam of the first intensity and incident it onto the silicon carbide wafer to be tested;
[0007] The polarizing component is used to filter the scattered light passing through the silicon carbide wafer to be tested, so that the parallel light passing through the silicon carbide wafer to be tested is incident on the photosensitive component.
[0008] The photosensitive component is used to detect the second light intensity of the parallel light at different incident positions;
[0009] The processing component is used to determine the transmittance at different locations of the silicon carbide wafer to be tested based on the first light intensity and the second light intensity; and to determine the doping uniformity of the silicon carbide wafer to be tested based on the transmittance at different locations of the silicon carbide wafer to be tested.
[0010] Preferably, in the above-mentioned detection device for the uniformity of doping of silicon carbide wafers, the wavelength range of the light beam is 390nm-3000nm.
[0011] Preferably, in the above-mentioned detection device for the uniformity of doping of silicon carbide wafers, the light beam is visible light or infrared light.
[0012] Preferably, in the above-mentioned detection device for the uniformity of doping of silicon carbide wafers, the light beam is incident perpendicularly onto the silicon carbide wafer to be detected.
[0013] Preferably, in the above-mentioned silicon carbide wafer doping uniformity detection device, the size range of the silicon carbide wafer to be detected is 4 inches to 15 inches.
[0014] Preferably, in the above-mentioned detection device for the uniformity of doping of silicon carbide wafers, the thickness range of the silicon carbide wafer to be detected is 200μm-1500μm.
[0015] Preferably, in the above-mentioned device for detecting the uniformity of doping of silicon carbide wafers, the polarizing component includes a polarizer.
[0016] Preferably, in the above-mentioned silicon carbide wafer doping uniformity detection device, the photosensitive component includes a plurality of photosensitive sensors.
[0017] Preferably, in the above-mentioned silicon carbide wafer doping uniformity detection device, the plurality of photosensitive sensor arrays are arranged.
[0018] Preferably, in the above-mentioned device for detecting the uniformity of doping of silicon carbide wafers, the size of the photosensitive sensor is 0.1mm × 0.1mm.
[0019] Using the above technical solution, this application provides a device for detecting the doping uniformity of a silicon carbide wafer. Based on the principle that different concentrations of doped atoms result in different light absorption ratios, the processing component determines the transmittance at different locations on the silicon carbide wafer based on the first light intensity of the light beam emitted from the light source and the second light intensity of the parallel light transmitted through the silicon carbide wafer at different incident positions on the photosensitive component. The doping uniformity of the silicon carbide wafer is then determined based on the transmittance at different locations on the silicon carbide wafer.
[0020] Furthermore, by setting up a polarizing component, the scattered light transmitted through the silicon carbide wafer to be tested is prevented from affecting the detection results, thereby improving the final detection accuracy. Attached Figure Description
[0021] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.
[0022] Figure 1 A device for detecting the doping uniformity of silicon carbide wafers is provided for embodiments of this utility model;
[0023] Figure 2A schematic diagram showing the transmittance of a silicon carbide crystal at different wavelengths, provided for an embodiment of this utility model;
[0024] Figure 3 A schematic diagram showing the transmittance of another silicon carbide crystal at different wavelengths, provided for an embodiment of this utility model;
[0025] Figure 4 This is a schematic diagram of the structure of a photosensitive component provided in an embodiment of the present utility model. Detailed Implementation
[0026] The embodiments of this application are described below with reference to the accompanying drawings. The terminology used in the implementation section of this application is only for explaining specific embodiments and is not intended to limit the application. Those skilled in the art will understand that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems. It should be noted that the directional terms appearing in this utility model are based on the relative positional relationships shown in the accompanying drawings and should not be considered as absolute limitations on this application.
[0027] Currently, the main technologies for detecting the doping uniformity of silicon carbide wafers include the following three techniques.
[0028] Existing technology 1: SIMS detection is a surface analysis technique based on mass spectrometry that can accurately test the impurity content of silicon carbide wafers, with a testing accuracy down to the ppm level. However, it has the following problems:
[0029] Problem 1: SIMS testing equipment and auxiliary materials are expensive, and the qualification requirements for testing personnel are high, resulting in high overall testing costs.
[0030] Question 2: The test area is generally less than 1 cm². 2 It is impossible to test the entire silicon carbide wafer.
[0031] Question 3: Conducting destructive testing on the surface of silicon carbide wafers is not a viable method for production testing.
[0032] Existing technology two: GDMS detection is a technique that uses a glow discharge power source as an ion source connected to a mass spectrometer for mass spectrometry determination, achieving a testing accuracy in the ppm-ppb range. However, it has the following problems:
[0033] Question 1: GDMS testing equipment and auxiliary materials are expensive, and the requirements for testing personnel qualifications are high, resulting in high overall testing costs.
[0034] Question 2: The test area is generally less than 1 cm². 2 It is impossible to test the entire silicon carbide wafer.
[0035] Question 3: Conducting destructive testing on the surface of silicon carbide wafers is not a viable method for production testing.
[0036] Existing technology three: resistivity testing technology. Indirect resistivity testing can reflect the doping concentration of different silicon carbide wafers. Currently, a resistivity tester with probes at both the top and bottom is used to characterize the resistivity of silicon carbide wafers. The silicon carbide wafer moves in the middle of the probe according to a programmed setting, and the resistivity at that point is measured. However, this technology has the following problems:
[0037] Question 1: The test results are the average resistivity under the probe diameter. If the area of uneven doping is smaller than the probe area, it cannot reflect the uneven doping situation.
[0038] Question 2: Generally, there is a distance between the points, making it impossible to measure the entire surface of the silicon carbide wafer 100%.
[0039] Existing technology four: visual inspection technology, which involves manually judging the doping uniformity of silicon carbide wafers by visually inspecting the color they exhibit. However, this method has the following problems:
[0040] Problem 1: Quantitative analysis is not possible; only qualitative judgment is possible, and subjective factors play a significant role.
[0041] Based on this, the present invention provides a device for detecting the doping uniformity of silicon carbide wafers. This device has low testing costs and requires minimal qualifications from testing personnel. The test data covers the entire surface of the silicon carbide wafer, eliminating any unmeasurable areas. It is a non-destructive test and can be used for testing during the production process. The measurement data is quantifiable and can provide feedback on areas <1mm². 2 The doping anomaly.
[0042] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0043] refer to Figure 1 , Figure 1 This invention provides a device for detecting the doping uniformity of a silicon carbide wafer. The device includes a light source 11, a detection fixture 12, a polarizing component 13, a photosensitive component 14, and a processing component 15; the detection fixture 12 is on which a silicon carbide wafer 16 to be detected is mounted.
[0044] The light source 11 is used to emit a light beam of first intensity and incident on the silicon carbide wafer 16 to be tested.
[0045] The polarizing component 13 is used to filter the scattered light passing through the silicon carbide wafer 16 to be tested, so that the parallel light passing through the silicon carbide wafer 16 to be tested is incident on the photosensitive component 14.
[0046] The photosensitive component 14 is used to detect the second light intensity of the parallel light at different incident positions.
[0047] The processing component 15 is used to determine the transmittance at different positions of the silicon carbide wafer 16 to be tested based on the first light intensity and the second light intensity; and to determine the doping uniformity of the silicon carbide wafer 16 to be tested based on the transmittance at different positions of the silicon carbide wafer 16 to be tested.
[0048] Specifically, in the embodiments of this utility model, refer to Figure 2 , Figure 2 This is a schematic diagram showing the transmittance of a silicon carbide crystal at different wavelengths, provided as an embodiment of the present invention. (Refer to...) Figure 3 , Figure 3 This is a schematic diagram showing the transmittance of another silicon carbide crystal at different wavelengths, provided as an embodiment of the present invention. Figure 2 Curve 1 represents the transmittance curves of undoped silicon carbide crystals at different wavelengths, and curve 2 represents the transmittance curves of N-type doped silicon carbide crystals at different wavelengths. Figure 3 Curve 3 represents the transmittance curves of undoped silicon carbide crystals at different wavelengths, and curve 4 represents the transmittance curves of N-type doped silicon carbide crystals at different wavelengths.
[0049] like Figure 2 and Figure 3 As shown, silicon carbide crystals have good transmittance in the wavelength range >400nm. Doped atoms have a partial absorption effect on light under different wavelength conditions. If the types of doped atoms are the same but the concentrations of doped atoms are different, the absorption ratio of light will be different. Therefore, the doped silicon carbide crystals exhibit different transmittance. Thus, in this embodiment of the invention, the doping uniformity of the silicon carbide wafer 16 under test is reflected by the change in transmittance at different positions. Specifically, as follows:
[0050] Based on the principle that different concentrations of doped atoms result in different light absorption ratios, the processing component 15 determines the transmittance at different locations on the silicon carbide wafer 16 under test by using the first light intensity of the beam emitted from the light source 11 and the second light intensity of the parallel light transmitted through the silicon carbide wafer 16 at different incident positions on the photosensitive component 14. The doping uniformity of the silicon carbide wafer 16 is then determined based on the transmittance at these different locations. Furthermore, the polarizing component 13 is used to prevent scattered light transmitted through the silicon carbide wafer 16 from affecting the detection results, thereby improving the final detection accuracy.
[0051] The wavelength range of the light beam emitted by the light source 11 is 390nm-3000nm. The light beam is visible light or infrared light. In this embodiment of the invention, infrared light is used as an example for explanation. The wavelength accuracy of the light beam emitted by the light source 11 is ±3nm, and the wavelength repeatability is 0.1nm. It adopts a parallel optical path design, which can stably output light beams of different intensities. Furthermore, the light beam is incident on the silicon carbide wafer 16 to be tested in a perpendicular manner, which can ensure that all parallel light passing through the silicon carbide wafer 16 to be tested is received by the photosensitive component 14.
[0052] The testing fixture 12 serves as a tooling for the silicon carbide wafer 16 under test during the doping uniformity testing process. It is compatible with silicon carbide wafers 16 with sizes ranging from 4 inches to 15 inches and thicknesses ranging from 200 μm to 1500 μm. In other words, in this embodiment of the invention, the size range of the silicon carbide wafer 16 under test can be 4 inches to 15 inches, for example, the size of the silicon carbide wafer 16 under test can be 4 inches, 6 inches, 8 inches, 12 inches, etc.; the thickness range of the silicon carbide wafer 16 under test in this embodiment of the invention is 200 μm to 1500 μm, for example, the thickness of the silicon carbide wafer 16 under test can be 200 μm, 300 μm, 350 μm, or 1000 μm, etc.
[0053] The polarizing component 13 includes, but is not limited to, a polarizer, and is used to filter the scattered light passing through the silicon carbide wafer 16 to be tested, so that the parallel light passing through the silicon carbide wafer 16 is incident on the photosensitive component 14. In other words, by filtering out the scattered light caused by inclusions or other impurities within the silicon carbide wafer 16 to be tested, the polarizing component 13 ensures that the photosensitive component 14 receives parallel light, avoiding the influence of scattered light passing through the silicon carbide wafer 16 on the detection results, thereby improving the final detection accuracy.
[0054] refer to Figure 4 , Figure 4This is a schematic diagram of a photosensitive component provided in an embodiment of the present invention. The photosensitive component 14 includes a plurality of photosensitive sensors 17. Each photosensitive sensor 17 detects at least one second light intensity. Based on this second light intensity and the first light intensity, the processing component 15 calculates the light transmittance at the position corresponding to this photosensitive sensor 17 in the silicon carbide wafer 16 to be tested. The light transmittance calculation method is as follows:
[0055] T=I t / I0 formula (1)
[0056] Where T represents transmittance; I t I0 represents the intensity of the second light intensity; I1 represents the intensity of the first light intensity.
[0057] With the array of multiple photosensitive sensors 17 arranged in this configuration, the test data can cover the entire surface of the silicon carbide wafer, eliminating any unmeasurable areas on the wafer surface. With a photosensitive sensor 17 size of 0.1mm × 0.1mm, a feedback area of <1mm² can be achieved. 2 The doping anomaly means that the minimum test area of the silicon carbide wafer 16 to be tested will be <1 mm. 2 .
[0058] The doping uniformity of the silicon carbide wafer 16 under test is determined by the processing component 15 based on the transmittance at different locations. The doping uniformity is calculated as follows:
[0059] Unif = (T) max -T min ) / A formula (2)
[0060] Where Unif represents doping uniformity; T max T represents the maximum transmittance. min A represents the minimum transmittance; A represents the average transmittance at all locations on the silicon carbide wafer 16 to be tested.
[0061] In this embodiment of the utility model, the processing component 15 includes, but is not limited to, a host computer. Its built-in software analyzes the signals received by all the photosensitive sensors 17, thereby analyzing the transmittance corresponding to different positions of the silicon carbide wafer 16 to be tested. Based on this result, a transmittance variation spectrum of the silicon carbide wafer 16 to be tested can also be output for the operator to view.
[0062] Optionally, based on the software settings of the processing component 15, different colors can be used to reflect the transmittance at different locations on the silicon carbide wafer 16 to be tested. This allows the operator to gain a preliminary understanding of the doping uniformity of the silicon carbide wafer 16 based on the output transmittance variation spectrum of the silicon carbide wafer 16 to be tested. Then, based on the actual data, the final test data can be obtained according to the above formula (2).
[0063] In summary, the silicon carbide wafer doping uniformity detection device provided by this utility model has low detection cost and low requirements for the qualifications of the detection personnel; the test data can cover the entire surface of the silicon carbide wafer, and there is no silicon carbide wafer surface that cannot be measured; it is a non-destructive test and can be used for detection in the production process; the measurement data is quantifiable and can provide feedback on areas <1mm². 2 The doping anomaly.
[0064] It should be noted that the technical solution of this utility model does not involve any improvement of methods or software programs; all signal processing and analysis can be achieved through existing mature technologies.
[0065] The above provides a detailed description of the device for detecting the doping uniformity of silicon carbide wafers provided by this utility model. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.
[0066] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.
[0067] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that elements inherent to a process, method, article, or apparatus that comprises a list of elements, or elements inherent to such processes, methods, articles, or apparatus, are also included. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0068] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A device for detecting the doping uniformity of silicon carbide wafers, characterized in that, The device for detecting the uniformity of doping of silicon carbide wafers includes: a light source, a detection fixture, a polarizing component, a photosensitive component, and a processing component; the silicon carbide wafer to be detected is mounted on the detection fixture. The light source is used to emit a light beam of the first intensity and incident it onto the silicon carbide wafer to be tested; The polarizing component is used to filter the scattered light passing through the silicon carbide wafer to be tested, so that the parallel light passing through the silicon carbide wafer to be tested is incident on the photosensitive component. The photosensitive component is used to detect the second light intensity of the parallel light at different incident positions; The processing component is used to determine the transmittance at different locations of the silicon carbide wafer to be tested based on the first light intensity and the second light intensity; and to determine the doping uniformity of the silicon carbide wafer to be tested based on the transmittance at different locations of the silicon carbide wafer to be tested.
2. The device for detecting the doping uniformity of silicon carbide wafers according to claim 1, characterized in that, The wavelength range of the light beam is 390nm-3000nm.
3. The device for detecting the doping uniformity of silicon carbide wafers according to claim 1, characterized in that, The light beam is visible light or infrared light.
4. The device for detecting the doping uniformity of silicon carbide wafers according to claim 1, characterized in that, The light beam is incident perpendicularly onto the silicon carbide wafer to be tested.
5. The device for detecting the doping uniformity of silicon carbide wafers according to claim 1, characterized in that, The size range of the silicon carbide wafer to be tested is 4 inches to 15 inches.
6. The device for detecting the doping uniformity of silicon carbide wafers according to claim 1, characterized in that, The thickness of the silicon carbide wafer to be tested ranges from 200μm to 1500μm.
7. The device for detecting the doping uniformity of silicon carbide wafers according to claim 1, characterized in that, The polarizing component includes a polarizer.
8. The device for detecting the doping uniformity of silicon carbide wafers according to any one of claims 1-7, characterized in that, The photosensitive component includes multiple photosensitive sensors.
9. The device for detecting the doping uniformity of silicon carbide wafers according to claim 8, characterized in that, The multiple photosensitive sensor arrays are arranged in a row.
10. The device for detecting the doping uniformity of silicon carbide wafers according to claim 8, characterized in that, The size of the photosensitive sensor is 0.1mm × 0.1mm.