Wafer edge washing effect detection method and device, wafer and wafer processing method
By monitoring the work function difference and reflectivity of the wafer surface material, combined with the compensation voltage value, accurately judge the wafer edge washing effect and residual degree, the problems of inaccurate detection and incomplete removal in the prior art are solved, and efficient wafer edge washing effect and product quality improvement are achieved.
Patent Information
- Application Number
- CN202510089323.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-20
- Publication Date
- 2025-04-25
AI Technical Summary
In the prior art, the wafer edge washing effect is inaccurate, and it is difficult to completely remove edge washing residues, which affects the yield and reliability of the wafer product.
By monitoring the work function difference of the surface material of the wafer to be detected in the preset area, combining the compensation voltage value and reflectivity measurement, the edge washing effect and residual degree are judged, and the edge washing condition is adjusted according to the first-order derivative change curve of the reflectivity.
It realizes accurate judgment of the wafer edge washing effect and thorough removal of residues, improves the wafer edge washing effect, reduces the occurrence of adverse problems, and improves the yield and reliability of the product.
Smart Images
Figure CN119890067A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of semiconductor integrated circuit manufacturing, and in particular relates to a wafer edge washing effect detection method and device, and a wafer and a processing method thereof. Background Art
[0002] Wafer edge cleaning refers to the cleaning process performed on the edge of the wafer in various links of wafer manufacturing. In the current back-end process, the problem of Cu (copper) residue on the surface edge of the wafer after edge cleaning is particularly important.
[0003] Copper is widely used as an electrical interconnect material in semiconductor circuits on wafers due to its low resistivity. However, copper easily diffuses into the silicon substrate and is not easily removed in certain chemical solutions, resulting in copper residue on the wafer surface. The diffusion and residue of copper may cause short circuits or other electrical failures, and the residual or diffused copper may easily fall off, resulting in particle defects on the wafer, which seriously affects the product yield and performance reliability of the wafer.
[0004] However, in the prior art, the effect of wafer edge cleaning is generally detected only through optical detection to obtain the edge cleaning width, and the specific degree of edge removal and the degree of copper residue cannot be determined. Therefore, after the wafer edge is cleaned, it is impossible to accurately judge whether the copper is completely removed, resulting in the inability to ensure that the residual copper residue is completely removed during the wafer edge cleaning process, which brings hidden dangers to the yield and reliability of the wafer products.
[0005] Therefore, there is an urgent need for a structure or method that can accurately determine the effect of wafer edge cleaning and completely remove edge cleaning residues.
[0006] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology part of the present application. Summary of the invention
[0007] In view of the above shortcomings of the prior art, the purpose of the present invention is to provide a wafer edge cleaning effect detection method and device and a wafer and its processing method, which are used to solve the problems in the prior art of inaccurate wafer edge cleaning effect judgment and difficulty in completely removing edge cleaning residues.
[0008] To achieve the above object, the present invention provides a method for detecting wafer edge cleaning effect, the detection method comprising:
[0009] A wafer to be inspected that has undergone an edge cleaning process is provided, wherein a first material layer on an edge surface of the wafer to be inspected is removed, and a second material layer is exposed on the edge surface of the wafer to be inspected; an area where the first material layer is exposed on the surface of the wafer to be inspected is preset as a first area, and an area where the second material layer is exposed on the surface of the wafer to be inspected is preset as a second area;
[0010] Monitor the work function difference of the surface material of the wafer to be inspected in the first area and the second area; when the work function difference is not equal to 0 and is less than the difference threshold, judge that the edge cleaning effect of the wafer to be inspected is unqualified and there is a first material layer residue in the second area; when the work function difference is not equal to 0 and is not less than the difference threshold, judge that the edge cleaning effect of the wafer to be inspected is qualified and there is no first material layer residue in the second area; when the work function difference is equal to 0, judge that the edge cleaning effect of the wafer to be inspected is unqualified and the first material layer in the second area is not removed.
[0011] Optionally, the method for monitoring the work function difference of the surface material of the wafer to be inspected in the first area and the second area is: setting a Kelvin probe above the wafer to be inspected, applying a compensation voltage to the Kelvin probe and making the Kelvin probe vibrate according to a preset state, and monitoring the current change passing through the Kelvin probe; when the current change in the first area is monitored to be 0, the corresponding compensation voltage is obtained as the first surface voltage value of the first area; when the current change in the second area is monitored to be 0, the corresponding compensation voltage is obtained as the second surface voltage value of the second area; and the difference between the first surface voltage value and the second surface voltage value is used to represent the work function difference.
[0012] Optionally, a length of the second region along a radial direction of the wafer to be inspected is less than 3 mm.
[0013] The present invention also provides a wafer processing method, when it is determined in any of the above-mentioned wafer edge washing detection methods that the edge washing effect of the wafer to be detected is unqualified and there is a first material layer residue in the second area, the reflectivity of the surface of the wafer to be detected is measured along the radial direction of the wafer to be detected, and a reflectivity change curve of each position of the surface of the wafer to be detected along the radial distribution is obtained; the residual distribution position information of the first material layer in the second area is determined by the reflectivity change curve;
[0014] The second area of the wafer to be inspected is again cleaned according to preset conditions based on the residue distribution position information.
[0015] Optionally, the method for measuring the reflectivity of the surface of the wafer to be inspected is: using an ellipsometer to incident a first polarized light on the surface of the wafer to be inspected with a preset step size, and the first polarized light is incident on the surface of the wafer to be inspected and then reflects a second polarized light to the ellipsometer; the ellipsometer receives and measures the polarization state change of the second polarized light and the first polarized light, and then calculates the reflectivity of the surface of the wafer to be inspected on which the first polarized light is incident based on the measured polarization state change.
[0016] Optionally, the preset step length is equal to a spot diameter of the first polarized light.
[0017] Optionally, by obtaining the reflectivity of each position along the radial distribution on the surface of the wafer to be inspected, a first-order derivative change curve of the reflectivity at each position along the radial distribution on the surface of the wafer to be inspected is obtained, and the residual distribution position information of the first material layer in the second area is judged by the first-order derivative change curve of the reflectivity.
[0018] Optionally, a linear fitting relationship between the first material layer of different thicknesses on the second material layer and the corresponding reflectivity of the first material layer is obtained by experimental measurement, and the thickness of the first material layer corresponding to the reflectivity measured in the second area is found through the linear fitting relationship to determine the edge washing conditions for re-washing the first material layer in the second area of the wafer to be inspected.
[0019] The present invention also provides a wafer edge washing effect detection device, which adopts any one of the wafer edge washing effect detection methods described above to perform wafer edge washing effect detection, and the wafer edge washing effect detection device comprises: a detection platform, a Kelvin probe, a compensation voltage source, an ammeter, an ellipsometer, a driving structure and an analysis and judgment unit;
[0020] The detection table is used to place the wafer to be detected after edge cleaning; the Kelvin probe is located above the detection table, and is used to form a contact potential difference between the surface of the wafer to be detected placed on the detection table and the Kelvin probe through vibration; the compensation voltage source and the ammeter are both effectively electrically connected to the Kelvin probe, the compensation voltage source is used to provide a compensation voltage for the Kelvin probe, and the ammeter is used to monitor the current passing through the Kelvin probe; the ellipsometer is located above the detection table, and is used to detect the reflectivity of various positions on the surface of the wafer to be detected placed on the detection table; the driving structure is electrically connected to the Kelvin probe, and is used to drive the Kelvin probe to move on the surface of the wafer to be detected; the analysis and judgment unit is effectively electrically connected to the compensation voltage source, the ammeter, and the ellipsometer, so as to monitor the compensation voltage value provided by the compensation voltage source when the current change detected by the ammeter is 0, and receive the reflectivity measured by the ellipsometer, so as to analyze and judge the edge cleaning effect and residual distribution position information of the wafer to be detected.
[0021] Optionally, a diameter of the Kelvin probe is smaller than a length of the second region along a radial direction of the wafer to be inspected.
[0022] The present invention also provides a wafer, wherein the wafer adopts any one of the above-mentioned wafer edge washing effect detection methods or / and any one of the above-mentioned wafer edge washing effect detection devices to perform wafer edge washing effect detection, or / and the wafer is processed by any one of the above-mentioned wafer processing methods; the surface of the wafer includes a second material layer and a first material layer, the second material layer is located below the first material layer, the second material layer is exposed in a second area of the edge surface of the wafer after preset edge washing, and the first material layer is in a first area of the non-edge surface of the wafer after preset edge washing; the work functions of the first material layer and the second material layer are not equal, and the reflectivities of the first material layer and the second material layer are not equal.
[0023] As described above, the wafer edge cleaning effect detection method and device and the wafer and processing method thereof of the present invention have the following beneficial effects:
[0024] The present invention can accurately judge the edge removal degree and residual degree of the wafer by combining the compensation voltage value with the reflectivity measurement method, which is beneficial to improving the wafer edge cleaning effect and reducing the adverse problems caused by incomplete wafer edge cleaning;
[0025] The present invention determines the residual distribution position information through the reflectivity first-order derivative change curve, which can improve the detection accuracy of the residual distribution, thereby further improving the wafer edge cleaning effect;
[0026] The present invention can obtain the specific residual thickness from the measured reflectivity through the linear fitting relationship between the first material layer of different thicknesses and the corresponding reflectivity, thereby improving the accuracy of the conditions when the edge is washed again, improving the efficiency of wafer edge washing, and ensuring the effect of wafer edge washing;
[0027] The present invention improves the detection accuracy of the Kelvin probe on the wafer edge cleaning effect by setting the diameter of the Kelvin probe. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 The figure shows a partial side view schematic diagram of an ideal wafer after edge cleaning in the prior art.
[0029] Figure 2 The figure shows a top view schematically showing an ideal wafer edge cleaning condition in the prior art.
[0030] Figure 3 A partial side view schematic diagram showing the copper residue after wafer edge cleaning in an example of the prior art.
[0031] Figure 4 A partial side view schematic diagram showing the copper residue after wafer edge cleaning in an example of the prior art.
[0032] Figure 5 Shown is a schematic diagram of the structure presented by setting a Kelvin probe in an example of step 2 of the wafer edge cleaning effect detection method of the present invention.
[0033] Figure 6 Shown is a reflectivity change curve obtained in an example of step 2 of the wafer edge cleaning effect detection method of the present invention.
[0034] Figure 7 Shown is a reflectivity change curve obtained in an example of step 2 of the wafer edge cleaning effect detection method of the present invention.
[0035] Figure 8 Shown is a linear fitting relationship curve between reflectivity and thickness obtained in an example of step 4 of the wafer edge cleaning effect detection method of the present invention.
[0036] Description of Figure Numbers
[0037] 1. Wafer; 2. Copper; 3. Tantalum layer; 4. Residue; 5. First region; 6. Second region; 7. First material layer; 8. Second material layer; 9. Kelvin probe; 10. Compensation voltage source. DETAILED DESCRIPTION
[0038] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.
[0039] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the schematic diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.
[0040] For convenience of description, spatially relative terms such as "under", "below", "below", "below", "above", "on", etc. may be used herein to describe the relationship of one element or feature shown in the drawings to other elements or features. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the drawings.
[0041] In the context of the present application, a structure in which a first feature is described as being "above" a second feature may include embodiments in which the first and second features are in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.
[0042] It should be noted that the diagrams provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and therefore the diagrams only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complex; the quantity range given in the present invention includes the two boundary values of the quantity range by default without special restrictions.
[0043] In the prior art back-end process, the ideal situation after the wafer 1 is edge washed is as follows: Figure 1-Figure 2 As shown, Figure 1 This is a partial side view of the structural layer on the wafer 1 after the wafer 1 is edge cleaned. Figure 2 The top view of the wafer 1 after edge cleaning shows that there is no copper residue 4 in the second area 6 of the edge of the wafer 1 after edge cleaning, and the copper 2 only exists in the first area 5. The second area 6 reveals the tantalum layer 3 under the copper 2. Copper is widely used as an electrical interconnect material in the semiconductor circuit of the wafer 1 due to its low resistivity. However, copper easily diffuses into the silicon substrate and is not easily removed in certain chemical solutions, resulting in copper residue 4 in the second area 6 on the surface of the wafer 1 after edge cleaning. Figure 3-Figure 4The figure shows two cases of copper residue 4; the diffusion and residue 4 of copper may cause short circuit or other electrical faults, and the residue 4 or diffused copper may fall off easily, thereby causing particle defects and other undesirable problems on the wafer 1, which seriously affects the product yield and performance reliability of the wafer 1. When detecting the edge washing effect of the wafer 1 in the prior art, generally only the edge washing width is obtained by optical detection, and the specific edge removal degree and the copper residue 4 degree cannot be determined. Therefore, after the edge washing of the wafer 1, it is impossible to accurately judge whether the copper is completely removed, resulting in the inability to ensure that the residual copper residue 4 is completely removed during the edge cleaning process of the wafer 1, which brings hidden dangers to the yield and reliability of the wafer 1 product.
[0044] The present invention provides a method for detecting edge washing effect of wafer 1. The method for detecting edge washing effect of wafer 1 of the present invention will be described in detail below. It should be noted that the above sequence does not strictly represent the sequence of the method for detecting edge washing effect of wafer 1 protected by the present invention, and those skilled in the art can change it according to the actual detection steps.
[0045] First, perform step A1, such as Figure 3-Figure 4 As shown, a wafer 1 to be inspected that has undergone an edge cleaning process is provided, the first material layer 7 on the edge surface of the wafer 1 to be inspected is removed, and the second material layer 8 is exposed on the edge surface of the wafer 1 to be inspected; the area where the first material layer 7 is exposed on the surface of the wafer 1 to be inspected is preset to be a first area 5, and the area where the second material layer 8 is exposed on the surface of the wafer 1 to be inspected is preset to be a second area 6.
[0046] In one embodiment, the length of the second area 6 along the radial direction of the wafer 1 to be inspected is less than 3 mm.
[0047] Then, step A2 is performed to monitor the work function difference of the surface material of the wafer 1 to be detected in the first area 5 and the second area 6; when the work function difference is not equal to 0 and is less than the difference threshold, it is judged that the edge cleaning effect of the wafer 1 to be detected is unqualified and there is a problem in the second area 6. Figure 3 or Figure 4 There are residues 4 of the first material layer in the second area 6; when the work function difference is not equal to 0 and is not less than the difference threshold, it is judged that the edge cleaning effect of the wafer 1 to be inspected is qualified and there is no residue 4 of the first material layer in the second area 6; when the work function difference is equal to 0, it is judged that the edge cleaning effect of the wafer 1 to be inspected is unqualified and the first material layer 7 of the second area 6 has not been removed.
[0048] In one embodiment, a method for monitoring the work function difference of the surface material of the wafer 1 to be inspected in the first area 5 and the second area 6 is as follows: Figure 5As shown (the first material layer 7 and the second material layer 8 on the surface of the wafer 1 are not shown), a Kelvin probe 9 is arranged above the wafer 1 to be detected, a compensation voltage is applied to the Kelvin probe 9 and the Kelvin probe 9 is vibrated according to a preset state, and the current change passing through the Kelvin probe 9 is monitored; when the current change in the first area 5 is monitored to be 0, the corresponding compensation voltage is obtained as the first surface voltage value of the first area 5; when the current change in the second area 6 is monitored to be 0, the corresponding compensation voltage is obtained as the second surface voltage value of the second area 6; the difference between the first surface voltage value and the second surface voltage value is used to represent the work function difference.
[0049] The present invention also provides a wafer 1 processing method, which will be described in detail below. It should be noted that the above sequence does not strictly represent the sequence of the wafer 1 processing method protected by the present invention, and those skilled in the art may change it according to the actual processing steps.
[0050] First, step B1 is performed. When it is determined in any of the above-mentioned wafer 1 edge washing detection methods that the edge washing effect of the wafer 1 to be detected is unqualified and there are residues 4 of the first material layer in the second area 6, the reflectivity of the surface of the wafer 1 to be detected is measured along the radial direction of the wafer 1 to be detected, and a reflectivity change curve of each position of the surface of the wafer 1 to be detected along the radial distribution is obtained; the distribution position information of the residue 4 of the first material layer 7 in the second area 6 is determined by the reflectivity change curve.
[0051] In one embodiment, Figure 6 For Figure 3 The reflectivity change curve obtained by the edge washing effect of the wafer 1 in the figure, wherein the horizontal axis represents the various positions of the first material layer 7 distributed radially from a position 3 mm away from the edge of the wafer 1 along the radial direction to the edge of the wafer 1, and the unit is millimeter, and the vertical axis represents the reflectivity corresponding to each radial position of the first material layer 7.
[0052] In one embodiment, Figure 7 For Figure 4 The reflectivity change curve obtained by the edge washing effect of the wafer 1 in the figure, wherein the horizontal axis represents the various positions of the first material layer 7 distributed radially from a position 3 mm away from the edge of the wafer 1 along the radial direction to the edge of the wafer 1, and the unit is millimeter, and the vertical axis represents the reflectivity corresponding to each radial position of the first material layer 7.
[0053] It can be seen that Figure 6-Figure 7 The reflectivity change curve shown in Figure 3-Figure 4 The corresponding first material layer 7 after edge cleaning of the wafer 1 is specifically distributed at the residual position 4 on the surface of the wafer 1.
[0054] In one embodiment, the method for measuring the reflectivity of the surface of the wafer 1 to be inspected is: using an ellipsometer to incident a first polarized light on the surface of the wafer 1 to be inspected with a preset step size, and the first polarized light is incident on the surface of the wafer 1 to be inspected and then reflects a second polarized light to the ellipsometer; the ellipsometer receives and measures the polarization state change of the second polarized light and the first polarized light, and then calculates the reflectivity of the surface of the wafer 1 to be inspected on which the first polarized light is incident based on the measured polarization state change.
[0055] In one embodiment, the preset step length is equal to the spot diameter of the first polarized light.
[0056] In one embodiment, by obtaining the reflectivity of each position along the radial distribution on the surface of the wafer 1 to be inspected, a first-order derivative change curve of the reflectivity at each position along the radial distribution on the surface of the wafer 1 to be inspected is obtained, and the distribution position information of the residue 4 of the first material layer 7 in the second region 6 is judged by the first-order derivative change curve of the reflectivity.
[0057] The present invention determines the distribution position information of the residue 4 through the reflectivity first-order derivative change curve. The position where the first-order derivative of the reflectivity changes significantly is the position where the residue 4 of the first material layer is distributed in the second area. Compared with directly using the reflectivity change curve, the detection accuracy of the residue 4 position distribution of the first material layer 7 in the second area 6 can be improved, thereby further improving the edge washing effect of the wafer 1.
[0058] Then, step B2 is performed to wash the second area 6 of the wafer 1 to be inspected again according to preset conditions based on the distribution position information of the residue 4.
[0059] The present invention measures the compensation voltage value and reflectivity of the first area 5 and the second area 6, and can accurately determine the edge removal degree and residual degree of the wafer 1 by combining the measurements, so as to perform edge washing again on the first material layer 7 remaining in the second area 6 after edge washing of the wafer 1, which is beneficial to improving the edge washing effect of the wafer 1, reducing the adverse problems caused by incomplete edge washing of the wafer 1, and is beneficial to improving the product yield and reliability of the wafer 1.
[0060] In one embodiment, a linear fitting relationship between the first material layer 7 of different thicknesses and the corresponding reflectivity of the first material layer 7 on the second material layer 8 is obtained by experimental measurement. The thickness of the first material layer 7 corresponding to the reflectivity measured in the second area 6 is found through the linear fitting relationship, and the edge washing conditions for re-washing the first material layer 7 in the second area 6 of the wafer 1 to be inspected are determined.
[0061] By obtaining the linear fitting relationship between the first material layer 7 of different thicknesses and the corresponding reflectivity in advance, the present invention can obtain the specific thickness of the corresponding residue 4 from the reflectivity measured in real time subsequently, thereby improving the accuracy of the conditions when washing the edge again, improving the efficiency of washing the edge of the wafer 1, and ensuring the effect of washing the edge of the wafer 1.
[0062] In one embodiment, Figure 8 The figure shows the linear fitting relationship between the first material layer 7 of different thicknesses on the second material layer 8 and the corresponding reflectivity (REF) of the first material layer 7 obtained by experimental measurement, wherein the horizontal axis represents the thickness of each position of the first material layer 7 in angstroms, and the vertical axis represents the reflectivity (REF) corresponding to each position of the first material layer 7. The line connecting the points is the data obtained by actual measurement, and the curve is the fitting curve obtained by fitting. It can be seen that the reflectivity is strongly correlated with the thickness of the first material layer 7. By obtaining the reflectivity corresponding to a certain position, the thickness of the first material layer 7 corresponding to the reflectivity at that position can be obtained.
[0063] Specifically, the obtained linear fitting relationship can be obtained before detecting the edge washing effect of the wafer 1. After measuring the reflectivity, the obtained reflectivity can be directly matched in the linear fitting relationship to obtain the thickness of the first material layer 7 corresponding to the reflectivity, so as to judge the residual 4 thickness of the first material layer 7 at the corresponding position in the second area 6, so as to adjust the edge washing conditions such as the time and concentration for edge washing in the corresponding position when the second area 6 is washed again, so as to more accurately remove the residual 4 first material layer 7 in the second area 6, avoid damage to the wafer 1 caused by excessive edge washing, and at the same time ensure the edge washing effect after the second edge washing.
[0064] The present invention also provides a wafer 1 edge washing effect detection device, the wafer 1 edge washing effect detection device adopts any one of the wafer 1 edge washing effect detection methods described above to perform wafer 1 edge washing effect detection, the wafer 1 edge washing effect detection device comprises: a detection platform, a Kelvin probe 9, a compensation voltage source 10, an ammeter, an ellipsometer, a driving structure and an analysis and judgment unit;
[0065] The detection table is used to place the wafer 1 to be detected after edge washing; the Kelvin probe 9 is located above the detection table, and is used to form a contact potential difference between the surface of the wafer 1 to be detected placed on the detection table through vibration; the compensation voltage source 10 and the ammeter are both effectively electrically connected to the Kelvin probe 9, the compensation voltage source 10 is used to provide a compensation voltage for the Kelvin probe 9, and the ammeter is used to monitor the current passing through the Kelvin probe 9; the ellipsometer is located above the detection table, and is used to detect the reflectivity of each position on the surface of the wafer 1 to be detected placed on the detection table; the driving structure is electrically connected to the Kelvin probe 9, and is used to drive the Kelvin probe 9 to move on the surface of the wafer 1 to be detected; the analysis and judgment unit is effectively electrically connected to the compensation voltage source 10, the ammeter, and the ellipsometer, so as to monitor the compensation voltage value provided by the compensation voltage source 10 when the current change detected by the ammeter is 0, and receive the reflectivity measured by the ellipsometer, so as to analyze and judge the edge washing effect of the wafer 1 to be detected and the residual 4 distribution position information.
[0066] In one embodiment, the diameter of the Kelvin probe 9 is smaller than the radial length of the second region 6 along the wafer 1 to be inspected.
[0067] The present invention sets the relationship between the diameter of the Kelvin probe 9 and the width of the second area 6, thereby improving the accuracy of the compensation voltage value in the second area 6 of the edge of the wafer 1 measured by the Kelvin probe 9, and improving the detection accuracy of the edge cleaning effect of the wafer 1 by the Kelvin probe 9.
[0068] In one embodiment, the length of the second region 6 along the radial direction of the wafer 1 to be inspected is 2.2 mm, and the diameter of the Kelvin probe 9 is 2 mm.
[0069] The present invention also provides a wafer 1, wherein the wafer 1 adopts any one of the above-mentioned wafer 1 edge washing effect detection methods or / and any one of the above-mentioned wafer 1 edge washing effect detection devices to perform wafer 1 edge washing effect detection, or / and the wafer 1 is processed by any one of the above-mentioned wafer 1 processing methods; the surface of the wafer 1 includes a second material layer 8 and a first material layer 7, the second material layer 8 is located below the first material layer 7, the second material layer 8 is exposed in the second area 6 of the edge surface of the wafer 1 after edge washing, and the first area 5 of the non-edge surface of the wafer 1 after edge washing is the first material layer 7; the work functions of the first material layer 7 and the second material layer 8 are not equal, and the reflectivity of the first material layer 7 and the second material layer 8 are not equal.
[0070] In one embodiment 2, the first material layer 7 is copper, and the second material layer 8 is tantalum or tantalum nitride. Specifically, the materials of the first material layer 7 and the second material layer 8 can also be selected from other suitable materials according to requirements, all of which are within the protection scope of the present invention.
[0071] In summary, the wafer edge cleaning effect detection method and device, wafer and processing method thereof of the present invention can accurately judge the edge removal degree and residual degree of the wafer by combining the compensation voltage value with the reflectivity measurement method, which is beneficial to improving the wafer edge cleaning effect and reducing the adverse problems caused by incomplete wafer edge cleaning; at the same time, the residual distribution position information is judged by the reflectivity first-order derivative change curve, which can improve the detection accuracy of the residual distribution, thereby further improving the wafer edge cleaning effect; in addition, through the linear fitting relationship between the first material layer of different thicknesses and the corresponding reflectivity, the specific thickness of the residue can be obtained from the measured reflectivity, thereby improving the accuracy of the conditions when washing the edge again, improving the wafer edge cleaning efficiency, and ensuring the wafer edge cleaning effect; finally, by setting the diameter of the Kelvin probe, the detection accuracy of the Kelvin probe on the wafer edge cleaning effect is improved.
[0072] Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.
[0073] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.
Claims
1. A wafer edge cleaning effect detection method, characterized in that: The detection method comprises: A wafer to be inspected that has undergone an edge cleaning process is provided, wherein a first material layer on an edge surface of the wafer to be inspected is removed, and a second material layer is exposed on the edge surface of the wafer to be inspected; an area where the first material layer is exposed on the surface of the wafer to be inspected is preset as a first area, and an area where the second material layer is exposed on the surface of the wafer to be inspected is preset as a second area; Monitor the work function difference of the surface material of the wafer to be inspected in the first area and the second area; when the work function difference is not equal to 0 and is less than the difference threshold, judge that the edge cleaning effect of the wafer to be inspected is unqualified and there is a first material layer residue in the second area; when the work function difference is not equal to 0 and is not less than the difference threshold, judge that the edge cleaning effect of the wafer to be inspected is qualified and there is no first material layer residue in the second area; when the work function difference is equal to 0, judge that the edge cleaning effect of the wafer to be inspected is unqualified and the first material layer in the second area is not removed.
2. The wafer edge cleaning effect detection method according to claim 1, characterized in that: The method for monitoring the work function difference of the surface material of the wafer to be detected in the first area and the second area is as follows: a Kelvin probe is arranged above the wafer to be detected, a compensation voltage is applied to the Kelvin probe and the Kelvin probe is vibrated in a preset state, and a current change passing through the Kelvin probe is monitored; when the current change in the first area is monitored to be 0, a corresponding compensation voltage is obtained as a first surface voltage value of the first area; When it is monitored that the current change in the second area is 0, the corresponding compensation voltage is the second surface voltage value of the second area; The work function difference is represented by a difference between the first surface voltage value and the second surface voltage value.
3. The wafer edge cleaning effect detection method according to claim 1, characterized in that: The length of the second area along the radial direction of the wafer to be inspected is less than 3 mm.
4. A wafer processing method, characterized in that: The processing method comprises: when it is determined in the wafer edge cleaning effect detection method described in any one of claims 1 to 3 that the edge cleaning effect of the wafer to be detected is unqualified and there is a first material layer residue in the second area, measuring the reflectivity of the surface of the wafer to be detected along the radial direction of the wafer to be detected, and obtaining a reflectivity change curve of each position of the surface of the wafer to be detected along the radial distribution; judging the residual distribution position information of the first material layer in the second area by the reflectivity change curve; The second area of the wafer to be inspected is again cleaned according to preset conditions based on the residue distribution position information.
5. The wafer processing method according to claim 4, characterized in that: The method for measuring the reflectivity of the surface of the wafer to be detected is: using an ellipsometer to incident a first polarized light on the surface of the wafer to be detected with a preset step length, and after the first polarized light is incident on the surface of the wafer to be detected, a second polarized light is reflected to the ellipsometer; The ellipsometer receives and measures the polarization state changes of the second polarized light and the first polarized light, and then calculates the reflectivity of the surface of the wafer to be inspected on which the first polarized light is incident based on the measured polarization state changes.
6. The wafer processing method according to claim 5, characterized in that: The preset step length is equal to the spot diameter of the first polarized light.
7. The wafer processing method according to claim 4, characterized in that: By obtaining the reflectivity of each position along the radial distribution on the surface of the wafer to be inspected, a first-order derivative change curve of the reflectivity at each position along the radial distribution on the surface of the wafer to be inspected is obtained, and the residual distribution position information of the first material layer in the second area is judged by the first-order derivative change curve of the reflectivity.
8. The wafer processing method according to claim 4, characterized in that: The experimental measurement obtains a linear fitting relationship between the first material layer of different thicknesses on the second material layer and the corresponding reflectivity of the first material layer. The thickness of the first material layer corresponding to the reflectivity measured in the second area is found through the linear fitting relationship, and the edge washing conditions for re-washing the first material layer in the second area of the wafer to be inspected are determined.
9. A wafer edge cleaning effect detection device, characterized in that: The wafer edge washing effect detection device adopts the wafer edge washing effect detection method according to any one of claims 1 to 3 to detect the wafer edge washing effect, and the wafer edge washing effect detection device comprises: a detection platform, a Kelvin probe, a compensation voltage source, an ammeter, an ellipsometer, a driving structure and an analysis and judgment unit; The detection table is used to place the wafer to be detected after edge cleaning; the Kelvin probe is located above the detection table, and is used to form a contact potential difference between the surface of the wafer to be detected placed on the detection table and the Kelvin probe through vibration; the compensation voltage source and the ammeter are both effectively electrically connected to the Kelvin probe, the compensation voltage source is used to provide a compensation voltage for the Kelvin probe, and the ammeter is used to monitor the current passing through the Kelvin probe; the ellipsometer is located above the detection table, and is used to detect the reflectivity of various positions on the surface of the wafer to be detected placed on the detection table; the driving structure is electrically connected to the Kelvin probe, and is used to drive the Kelvin probe to move on the surface of the wafer to be detected; the analysis and judgment unit is effectively electrically connected to the compensation voltage source, the ammeter, and the ellipsometer, so as to monitor the compensation voltage value provided by the compensation voltage source when the current change detected by the ammeter is 0, and receive the reflectivity measured by the ellipsometer, so as to analyze and judge the edge cleaning effect and residual distribution position information of the wafer to be detected.
10. The wafer edge cleaning effect detection device according to claim 9, characterized in that: The diameter of the Kelvin probe is smaller than the length of the second region along the radial direction of the wafer to be inspected.
11. A wafer, characterized in that: The wafer is subjected to wafer edge washing effect detection using the wafer edge washing effect detection method described in any one of claims 1 to 3 or / and the wafer edge washing effect detection device described in any one of claims 9 to 10, or / and the wafer is processed by the wafer processing method described in any one of claims 4 to 8; the surface of the wafer comprises a second material layer and a first material layer, the second material layer is located below the first material layer, the second material layer is exposed in a second area of the edge surface after the wafer is preset to be edge washed, and the first material layer is exposed in a first area of the non-edge surface of the wafer after the wafer is preset to be edge washed; The work functions of the first material layer and the second material layer are not equal, and the reflectivities of the first material layer and the second material layer are not equal.