Wafer metal film thickness measuring instrument and measuring method

Abstract

This disclosure provides an instrument and method for measuring the thickness of a wafer metal thin film. The measuring method is used in the instrument for measuring the thickness of a wafer metal thin film. The instrument includes: a carrier disk for supporting a wafer, wherein the upper surface of the wafer is covered with a metal thin film; an eddy current sensor disposed above the carrier disk, configured to generate an eddy current magnetic field within the metal thin film of the wafer using the eddy current effect, and to detect the intensity of the eddy current magnetic field to generate a corresponding output signal; and a distance sensor disposed above the carrier disk for measuring the lift-off height of the eddy current sensor from the wafer. The measurement method includes: acquiring the target output signal generated by the eddy current sensor and the target lift-off height measured by the distance sensor when the carrier disk supports the wafer to be tested; and determining the thickness of the metal thin film of the wafer to be tested based on the target output signal and the target lift-off height.

Description

[0001] This application is a divisional application of the invention patent application filed on May 6, 2023, with application number 202310505303.8. Technical Field

[0002] This disclosure relates to the field of semiconductor technology, and more specifically to an instrument and method for measuring the thickness of a wafer metal thin film, electronic equipment, computer-readable storage medium, and computer program product. Background Technology

[0003] Integrated circuits (ICs) are the core and lifeline of the information technology industry. ICs are generally formed by successively depositing conductive layers, semiconductor layers, or insulating layers on a silicon wafer. This results in a thin film of filler layers deposited on the wafer surface. During the manufacturing process, the filler layers need to be continuously planarized until a patterned top surface is exposed, in order to form conductive paths between the raised patterns.

[0004] With the rapid development of semiconductor materials and semiconductor manufacturing processes, there are increasingly more research methods for studying the thickness characteristics of metal films on wafer surfaces. Currently, not only are reliable semiconductor substrate materials and semiconductor process fabrication capabilities needed, but also stable and reliable testing tools are required to accurately determine the morphology of metal films on wafer surfaces. However, there are currently no commercially available measurement devices capable of accurately measuring the thickness of metal films on wafer surfaces.

[0005] The methods described in this section are not necessarily methods that had been previously conceived or adopted. Unless otherwise specified, no method described in this section should be assumed to be prior art simply because it is included in this section. Similarly, unless otherwise specified, the issues mentioned in this section should not be considered to be accepted in any prior art. Summary of the Invention

[0006] According to a first aspect of the present disclosure, a method for measuring the thickness of a wafer metal thin film is provided. The method is used in a wafer metal thin film thickness measuring instrument, which includes: a carrier disk for carrying a wafer, wherein the upper surface of the wafer is covered with a metal thin film; an eddy current sensor disposed above the carrier disk, configured to generate an eddy current magnetic field within the metal thin film of the wafer using the eddy current effect, and to detect the intensity of the eddy current magnetic field to generate a corresponding output signal; and a distance sensor disposed above the carrier disk for measuring the lift-off height of the eddy current sensor from the wafer. The measurement method includes: acquiring a target output signal generated by the eddy current sensor and a target lift-off height measured by the distance sensor when the carrier disk carries the wafer to be tested; and determining the thickness of the metal thin film of the wafer to be tested based on the target output signal and the target lift-off height.

[0007] According to a second aspect of the present disclosure, an instrument for measuring the thickness of a metal thin film on a wafer is provided, comprising: a carrier disk for carrying a wafer, wherein the upper surface of the wafer is covered with a metal thin film; an eddy current sensor disposed above the carrier disk, configured to generate an eddy current magnetic field within the metal thin film of the wafer using the eddy current effect, and to detect the intensity of the eddy current magnetic field to generate a corresponding output signal; a distance sensor disposed above the carrier disk for measuring the lift-off height of the eddy current sensor from the wafer; and a processor communicatively connected to the eddy current sensor and the distance sensor, configured to, when the carrier disk carries the wafer to be tested, acquire the target output signal generated by the eddy current sensor and the target lift-off height measured by the distance sensor, respectively; and to determine the thickness of the metal thin film of the wafer to be tested based on the target output signal and the target lift-off height.

[0008] According to a third aspect of the present disclosure, an electronic device is provided, comprising: at least one processor; and at least one memory having a computer program stored thereon, wherein the computer program, when executed by the at least one processor, causes the at least one processor to perform the above-described method for measuring the thickness of a wafer metal thin film.

[0009] According to a fourth aspect of the present disclosure, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, causes the processor to perform the above-described method for measuring the thickness of a wafer metal thin film.

[0010] According to a fourth aspect of the present disclosure, a computer program product is provided, including a computer program that, when executed by a processor, causes the processor to perform the measurement method described above.

[0011] According to one or more embodiments of this disclosure, when measuring the thickness of a metal thin film on a wafer, the influence of the output signal magnitude of the eddy current sensor and the lift-off height on the measurement result is comprehensively considered. Therefore, the thickness value of the metal thin film obtained by the measurement method of this disclosure is more accurate than the thickness value determined by using only the output signal of the eddy current sensor. Attached Figure Description

[0012] The accompanying drawings exemplify embodiments and form part of the specification, serving to illustrate exemplary implementations of the embodiments together with the textual description. The illustrated embodiments are for illustrative purposes only and do not limit the scope of the claims. Throughout the drawings, the same reference numerals refer to the same elements or similar but not necessarily identical elements.

[0013] Figure 1 This is a schematic diagram illustrating the structure of a measuring instrument for measuring the thickness of a wafer metal thin film according to an embodiment of the present disclosure;

[0014] Figure 2 This is a flowchart illustrating a method for measuring the thickness of a wafer metal thin film according to an embodiment of the present disclosure;

[0015] Figure 3 This is a flowchart illustrating a method for measuring the thickness of a wafer metal thin film according to an embodiment of the present disclosure;

[0016] Figure 4 This is a flowchart illustrating a method for determining a first mapping relationship according to an embodiment of the present disclosure;

[0017] Figure 5 This is a flowchart illustrating a method for determining a second mapping relationship according to an embodiment of the present disclosure;

[0018] Figure 6 A graph showing the relationship between the lift-off height and the corresponding output signal obtained for a sample wafer according to an embodiment of the present disclosure is shown.

[0019] Figure 7 This is a flowchart illustrating a method for acquiring a target output signal and a target lift-off height according to embodiments of the present disclosure; and

[0020] Figure 8 This is a schematic diagram illustrating a preset path according to an embodiment of the present disclosure;

[0021] Figure 9 This is a schematic longitudinal cross-sectional view of a measuring instrument according to an embodiment of the present disclosure;

[0022] Figure 10 This diagram illustrates a 2D graphical display of the thickness of a metal thin film on a wafer to be inspected.

[0023] Figure 11 This diagram illustrates a 3D graphical display of the thickness of a metal thin film on a wafer to be inspected.

[0024] Figure 12 An example configuration of an electronic device that can be used to implement the methods described herein is shown. Detailed Implementation

[0025] The present disclosure will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other. Unless the context explicitly indicates otherwise, an element may be one or more unless the number of elements is not specifically limited. Furthermore, the numbering of steps or functional modules used in this disclosure is only for identifying each step or functional module and is not intended to limit the execution order of the steps or the connection relationship between the functional modules.

[0027] In this disclosure, unless otherwise stated, the use of terms such as "first," "second," etc., to describe various elements is not intended to limit the positional, temporal, or importance relationships of these elements; such terms are merely used to distinguish one element from another. In some examples, the first element and the second element may refer to the same instance of that element, while in other cases, based on the context, they may refer to different instances.

[0028] In this disclosure, the terminology used in the description of the various examples is for the purpose of describing particular examples only and is not intended to be limiting. Unless the context clearly indicates otherwise, an element may be one or more unless the number of elements is specifically limited. Furthermore, the term "and / or" as used in this disclosure covers any one of the listed items and all possible combinations thereof.

[0029] The specific embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0030] According to embodiments of this disclosure, a method for measuring the thickness of a wafer metal thin film is first proposed, which is used in a wafer metal thin film thickness measuring instrument of this disclosure. To describe the measurement method of the embodiments of this disclosure in more detail, the measuring instrument for wafer metal thin film thickness will first be described here.

[0031] Figure 1 A schematic diagram of a wafer metal thin film thickness measuring instrument 100 according to an embodiment of the present disclosure is shown. Figure 1As shown, the measuring instrument 100 includes a carrier plate 30, an eddy current sensor 20, and a ranging sensor 50. The carrier plate 30 is used to carry a wafer, wherein the upper surface of the wafer is covered with a thin metal film. The carrier plate 30 may have an adsorption function, capable of adsorbing the wafer it carries, so that the wafer remains stationary relative to the carrier plate 30. The adsorption function can be implemented, for example, by a vacuum adsorption device. The eddy current sensor 20 is disposed above the carrier plate 30 and configured to excite an eddy current magnetic field within the thin metal film of the wafer using the eddy current effect, and detect the intensity of the eddy current magnetic field to generate a corresponding output signal. As an example, the eddy current sensor 20 may include an excitation coil, an induction coil, a coil frame, and a shielding shell. The excitation coil is supplied with an alternating signal of a fixed frequency, generating an alternating magnetic field, which in turn induces an electromotive force in the thin metal film and the induction coil. There is a coupled electromagnetic induction relationship between the excitation coil, the induction coil, and the thin metal film. The eddy current sensor 20, as the core component of the measuring instrument 100, is mainly used to excite an alternating electromagnetic field within the metal thin film and sense the changes in induced electromotive force (EMF) generated by the mutual inductance effect caused by metal thin films of different thicknesses. Under otherwise constant conditions, there is a one-to-one correspondence between the induced EMF and the thickness of the metal thin film; therefore, the output signal of the eddy current sensor 20 is related to the thickness of the metal thin film. The distance sensor 50 is positioned above the support plate 30 and is used to measure the lift-off height of the eddy current sensor 20 from the wafer. The distance sensor 50 includes, but is not limited to, millimeter-wave sensors, laser distance sensors, and infrared distance sensors. During the measurement process, the sampling frequency of the distance sensor 50 is, for example, consistent with the sampling frequency of the eddy current sensor 20, so as to output the lift-off height of the eddy current sensor 20 from the wafer in real time.

[0032] Continue to refer to Figure 1 In some embodiments, the measuring instrument 100 further includes a distance adjustment device 11, on which the eddy current sensor 20 and the distance sensor 50 are fixed. The distance adjustment device 11 is configured to adjust the lift-off height from the wafer surface. For example, the distance adjustment device 11 may include a stepper motor, the output of which is fixedly connected to the eddy current sensor 20 and the distance sensor 50 to drive them to move... Figure 1 The distance adjustment device 11 moves in the Z direction as shown. In some other embodiments, the distance adjustment device 11 may also include other drive mechanisms besides the stepper motor, as long as the distance adjustment device 11 can drive the eddy current sensor 20 and the ranging sensor 50 to move in the vertical direction. This disclosure does not limit the specific structure of the distance adjustment device 11.

[0033] Figure 2 A flowchart of a method 200 for measuring the thickness of a wafer metal thin film according to an embodiment of the present disclosure is shown.

[0034] like Figure 2 As shown, the measurement method 200 includes:

[0035] Step 210: When the wafer to be tested is carried on the carrier disk 30, the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the ranging sensor 50 are acquired respectively; and

[0036] Step 220: Determine the thickness of the metal thin film on the wafer to be inspected based on the target output signal and the target lift-off height.

[0037] In step 210, the tester can place the wafer to be tested on the carrier disk 30 and adjust the positions of the eddy current sensor 20 and the distance sensor 50 in the space above the carrier disk 30 to reach the preset measurement point. Then, the readings of the eddy current sensor 20 and the distance sensor 50 are acquired, namely, the target output signal and the target lift-off height.

[0038] As mentioned earlier, under otherwise unchanged conditions, there is a one-to-one correspondence between the output signal of the eddy current sensor 20 and the thickness of the metal thin film. Furthermore, the lift-off height also affects the resolution of the eddy current sensor 20; therefore, the output signal of the eddy current sensor 20 is also related to the lift-off height. Thus, in step 220, the thickness of the metal thin film on the wafer to be inspected can be determined jointly based on both the target output signal and the target lift-off height. In some embodiments, the functional relationship between the thickness of the metal thin film and the output signal of the eddy current sensor 20 and the lift-off height can be predetermined, and then the target output signal and the target lift-off height can be substituted into the aforementioned functional relationship to obtain the thickness of the metal thin film.

[0039] According to the measurement method 200 of one or more embodiments of the present disclosure, when measuring the thickness of the metal thin film on a wafer, the influence of the output signal magnitude of the eddy current sensor 20 and the lift-off height on the measurement result is comprehensively considered. Therefore, the thickness value of the metal thin film obtained by the measurement method of the present disclosure is more accurate than the thickness value determined by using only the output signal of the eddy current sensor 20.

[0040] Figure 3 A flowchart of a method 300 for measuring the thickness of a wafer metal thin film according to an embodiment of the present disclosure is shown.

[0041] like Figure 3 As shown, the measurement method 300 includes:

[0042] Step 310: Determine the first mapping relationship between the thickness of the metal thin film on the wafer and the output signal of the eddy current sensor 20 when the lift-off height measured by the ranging sensor 50 is a preset standard height, wherein the coefficients in the first mapping relationship are related to the resolution of the eddy current sensor 20.

[0043] Step 320: Determine the second mapping relationship between the lift-off height and the resolution of the eddy current sensor 20;

[0044] Step 330: Correct the coefficients in the first mapping relationship according to the second mapping relationship to obtain a third mapping relationship between the thickness of the metal thin film on the wafer and the output signal of the eddy current sensor 20, when the lift-off height measured by the ranging sensor 50 is the target lift-off height; and

[0045] Step 340: Determine the thickness of the metal thin film on the wafer to be tested based on the target output signal and the third mapping relationship.

[0046] In step 310, the preset standard height can be the lift-off height where the eddy current sensor 20 achieves the best detection effect. The size of the aforementioned standard height is related to the specific model and parameters of the measuring instrument 100. In some embodiments, the first mapping relationship can be predetermined and stored in the relevant memory of the measuring instrument 100. When calculating the thickness, the first mapping relationship can be retrieved from the memory. In other embodiments, the first mapping relationship can also be determined before measuring the thickness of the metal thin film on the wafer to be inspected. For example, the first mapping relationship can be fitted by acquiring the output signals of the eddy current sensor 20 corresponding to multiple metal thin film samples of different and known thicknesses. The first mapping relationship can be expressed as:

[0047] T=f(x) (1)

[0048] Where T represents the thickness of the metal thin film, and x is the output signal of the eddy current sensor 20. In some embodiments, f(x) can be a cubic function, i.e.,

[0049] T = Ax 3 +Bx 2 +Cx+D (2)

[0050] Wherein, A, B, and C are coefficients in the first mapping relationship, and these coefficients are directly related to the resolution of the eddy current sensor 20. Those skilled in the art will understand that the resolution of the eddy current sensor 20 is defined as the rate of change of the measured value (i.e., the magnitude of the output signal of the eddy current sensor 20) with the change in the thickness of the metal thin film. Whenever the thickness of the metal thin film changes by a unit thickness, if the magnitude of the change in the output signal of the eddy current sensor 20 is larger, it indicates a larger resolution; conversely, the smaller the change, the smaller the resolution. Therefore, according to the above definition, the coefficients A, B, and C in equation (2) are related to the resolution of the eddy current sensor 20.

[0051] As mentioned above, the lift-off height affects the resolution of the eddy current sensor 20. Therefore, a second mapping relationship exists between the lift-off height and the resolution of the eddy current sensor 20. Generally, the higher the lift-off height, the lower the resolution of the eddy current sensor 20. In step 320, similar to the first mapping relationship, the second mapping relationship can be predetermined and stored in the relevant memory of the measuring instrument 100. When calculating the thickness, the second mapping relationship can be retrieved from the memory. In some other embodiments, the second mapping relationship can also be determined before measuring the thickness of the metal thin film of the wafer to be inspected. For example, the second mapping relationship can be determined by acquiring the output signals of the eddy current sensor 20 corresponding to metal thin films of different thicknesses at different lift-off heights. The second mapping relationship can be expressed as:

[0052] K = g(h) (3)

[0053] Where K represents the resolution of the eddy current sensor 20, and h represents the lift-off height. Furthermore, the coefficients A, B, and C in equation (2) are related to K.

[0054] In step 330, the coefficients A, B, and C in equation (2) are corrected according to equation (3). Specifically, h = h1 (where h1 represents the target lift-off height) can be substituted into equation (3) to calculate the target resolution K1 of the eddy current sensor 20 at the target lift-off height. Subsequently, the coefficients A, B, and C in equation (2) are corrected using the target resolution K1 to obtain the corrected coefficients A1, B1, and C1, and finally, the third mapping relationship between the thickness of the metal film and the output signal of the eddy current sensor 20 at the target lift-off height is obtained. The third mapping relationship can be expressed as:

[0055] T = A1x 3 +B1x 2 +C1x+D (4)

[0056] In step 340, the value of the target output signal obtained in the previous step is substituted into equation (4) to calculate the thickness of the metal thin film on the wafer.

[0057] It should be further noted that although f(x) is shown as a cubic function in this embodiment, it is understood that f(x) can also be other function forms such as a linear function or a quadratic function. Similarly, g(h) can also be various function forms such as a linear function or a quadratic function. The embodiments of this disclosure do not limit the specific function form of f(x) or g(h). In addition, when f(x) is other function forms, the number of coefficients to be corrected will also be different. For example, in some examples, there may be one or two coefficients to be corrected, while in other examples, there may be three or more coefficients to be corrected.

[0058] Figure 4 A flowchart of a method 400 for determining a first mapping relationship according to an embodiment of the present disclosure is shown. Figure 4 As shown, the method 400 includes:

[0059] Step 410: After the eddy current sensor 20 is adjusted to a standard height position, the eddy current sensor 20 is used to detect multiple sample wafers in the sample wafer set to obtain the output signal of the eddy current sensor 20 corresponding to each sample wafer. Each sample wafer in the sample wafer set has a metal thin film of varying and known thickness covering its upper surface.

[0060] Step 420: Fit a first mapping relationship based on the thickness of each of the multiple sample wafers and the output signal of the eddy current sensor 20 corresponding to that sample wafer.

[0061] In the method of this embodiment, a first mapping relationship can be determined using a pre-prepared set of sample wafers. The set of sample wafers includes multiple sample wafers, such as 5, 6, 8, or 10 sample wafers. These sample wafers may have the same wafer body size, but the metal thin films covering their upper surfaces are different, and these metal thin films have different thicknesses. Specifically, these sample wafers may have metal thin films with progressively increasing thicknesses.

[0062] Before executing the method of this embodiment, the lift-off height is first adjusted to the standard height using the distance adjustment device 11 of the measuring instrument 100. This adjustment can be completed by observing the reading of the distance sensor 50. In step 410, multiple sample wafers from the sample wafer set can be placed sequentially on the carrier disk 30. Then, when each sample wafer is placed on the carrier disk 30, the output signal of the eddy current sensor 20 is acquired. Finally, a series of data on the thickness of the metal thin film and the corresponding output signal are obtained.

[0063] Table 1 shows relevant data for multiple sample wafers included in a set of sample wafers according to embodiments of the present disclosure.

[0064] Sample wafer number Thickness / nm Output signal 1 72.6 145.6 2 146 335.5 3 208.5 475.8 4 303.1 598.4 5 382 711.8 6 559.5 818.1

[0065] Table 1

[0066] In step 420, the relationship between the output signal of the eddy current sensor 20 and the thickness of the metal thin film on the sample wafer is established. This first mapping relationship can be determined by fitting. Fitting methods include, but are not limited to, piecewise linear fitting and least squares fitting.

[0067] The method of this embodiment can determine the first mapping relationship on-site using a sample wafer set. Compared to pre-determining the first mapping relationship and storing it in memory, the first mapping relationship calculated using the method of this embodiment will be more accurate. This is because different measuring instruments 100 may have individual differences, and using a pre-determined first mapping relationship cannot accurately reflect the relevant operating parameters of the measuring instrument 100 that should be operated. However, the first mapping relationship determined on-site can accurately reflect the aforementioned relevant operating parameters, thereby making the subsequently calculated thickness of the metal thin film more accurate.

[0068] Figure 5 A flowchart of a method 500 for determining a second mapping relationship according to an embodiment of the present disclosure is shown. Figure 5 As shown, the method 500 includes:

[0069] Step 510: The eddy current sensor 20 is sequentially adjusted to the position of each of the multiple sample heights;

[0070] Step 520: Determine the resolution corresponding to the eddy current sensor 20 at each sample height location, wherein step 520 further includes:

[0071] Step 521: Each sample wafer in the sample wafer set is detected using the eddy current sensor 20 to obtain the output signal of the eddy current sensor 20 corresponding to each sample wafer at the position of that sample height; and

[0072] Step 522: Determine the resolution of the eddy current sensor 20 at the sample height based on the thickness of each sample wafer in the sample wafer set and the output signal of the eddy current sensor 20 corresponding to each sample wafer at that sample height; and

[0073] Step 530: Determine a second mapping relationship based on multiple sample heights and the resolution of the eddy current sensor 20 corresponding to each of the multiple sample heights.

[0074] Multiple sample heights can be predetermined lift-off heights, and these sample heights can, for example, be in the form of an arithmetic sequence, meaning that two adjacent sample heights have the same height difference. In step 510, the lift-off height can be adjusted to a certain sample height using the distance adjustment device 11 of the measuring instrument 100, and this adjustment can be completed by observing the reading of the distance sensor 50.

[0075] In step 521, at any sample height, multiple sample wafers from the aforementioned sample wafer set are sequentially placed on the carrier disk 30. Then, when each sample wafer is placed on the carrier disk 30, the output signal of the eddy current sensor 20 is acquired. Finally, a series of data on the thickness of the metal thin film and the corresponding output signal are obtained.

[0076] Finally, a series of data on the thickness of metal thin films and the corresponding output signals were obtained. The data on the output signals of each sample wafer were similar to those shown in Table 1. However, due to the different lift-off heights, the output signals of each sample wafer were not the same as those shown in Table 1.

[0077] In step 522, the resolution of the eddy current sensor 20 at the sample height can be directly calculated using the data obtained in step 521.

[0078] For simplicity, let's assume the first mapping relationship T = f(x) is a linear function, i.e., T = Cx. Then, the resolution of the eddy current sensor 20 (or the coefficients in the first mapping relationship) can be directly calculated using data from two sample wafers with different metal film thicknesses. Specifically, the thickness difference of the metal film on each of the two sample wafers and the signal difference of the corresponding output signals can be calculated. Dividing the thickness difference by the signal difference yields the resolution of the eddy current sensor 20 at that sample height. It is understood that in some embodiments, the first mapping relationship T = f(x) can be a more complex function. In this case, more sample wafer data may be needed to calculate the resolution of the eddy current sensor 20. The specific calculation method depends on the function form of f(x) and will not be detailed here.

[0079] After determining the resolution of the eddy current sensor 20 at each sample height in step 520, the functional relationship between the resolution of the eddy current sensor 20 and the lift-off height, i.e., the second mapping relationship, can be determined in step 530 by means of fitting or other methods.

[0080] In other embodiments, the second mapping relationship described above can also be determined by using curves showing the relationship between different lift-off heights and the corresponding sensor output signals. Figure 6The diagram illustrates the relationship between the lift-off height and the corresponding sensor output signal obtained for a sample wafer according to an embodiment of the present disclosure. Figure 6 In this equation, the relationship between the output signal y and the lift-off height x can be expressed as a quadratic curve y = -1.197088x. 2 +4.250079x+0.163580. Using the method described above, multiple sets of output signal data corresponding to different sample heights of a single sample wafer can be obtained, and these data can be further used to fit a... Figure 6 The curve shown. Ultimately, based on multiple different sample wafers, multiple results can be obtained, such as... Figure 6 The curves shown are used to determine the relationship between resolution and lift-off height, i.e., the second mapping relationship mentioned above.

[0081] The following provides an implementation method for determining the first mapping relationship and the second mapping relationship, as well as for measuring the actual thickness of the metal thin film.

[0082] A first mapping relationship is established for the eddy current sensor 20, and this first mapping relationship is fitted. The fitting method can be the piecewise linear fitting or least squares fitting described above. The first mapping relationship can be expressed as a polynomial equation:

[0083] T = A0 + A1x 1 +A2x 2 +···+A n x n (5)

[0084] The above formula can be expressed as T = f(x), where T is the thickness of the measured sample, x is the output signal value of the eddy current sensor 20, and A0…A n The coefficient is related to the resolution of the eddy current sensor 20.

[0085] By analyzing different lift heights H0, H1...H n By calibrating the same set of sample wafers with different thicknesses, a relationship model between the output of the eddy current sensor 20 and the lift-off height H and sample thickness T can be obtained. This relationship model can be represented as a matrix, i.e.,

[0086]

[0087] T0, T1…T n These represent the different lift-off heights of the eddy current sensor 20: H0, H1…H n For the same sample wafer, the calculated thickness obtained by measuring the sensor output value should be as close as possible to the actual thickness T of the sample. The above equation (6) actually contains a second mapping relationship between the lift-off height and the resolution of the eddy current sensor 20.

[0088] Assuming a lift-off height H is used as the reference, a set of lift-off heights is set with λ as the step size. For example, each lift-off height is set at H-nλ,…,H-λ,H,H+λ,…,H+nλ, and labeled as H. -n H0…H n Calibration was performed using the same set of samples with different thicknesses to obtain the relationship model between the output of the eddy current sensor 20 and the lift-off height H and sample thickness T. The coefficients A in equation (6) above were then obtained. 00 …A nn Then, the actual thickness of the metal film can be measured.

[0089] When the measurement begins, the distance sensor 50 provides real-time feedback on the actual lift-off height h at each measurement point, and the processor of the measuring instrument 100 determines h within a given range. Within the range, where H y =H+yλ, and determine the characteristic curve at this time according to the above formula (6): T com =A y0 +A y1 x 1 +A y2 x 2 +···+A yn x n The eddy current sensor 20 calculates the thickness of the measured sample based on this characteristic curve.

[0090] Return to Figure 1 The measuring instrument 100 also includes a drive assembly configured to drive the eddy current sensor 20 and the distance sensor 50 to move relative to the support disk 30. The drive assembly may include a swing arm 10 and a rotating device 40. The eddy current sensor 20 and the distance sensor 50 are fixed to the swing arm 10, which is configured to drive them to move along a direction parallel to the diameter of the support disk 30, i.e., along... Figure 1 The movement is in the X direction as shown. The rotating device 40 is connected to the carrier disk 30 and configured to drive the carrier disk 30 to rotate, as... Figure 1 As shown, the rotating device 40 drives the carrier disk 30 to rotate in the direction indicated by the arrow. Both the swing arm 10 and the rotating device 40 can be implemented by motors (e.g., stepper motors and rotary motors). By combining the translational movement of the swing arm 10 and the distance adjustment device 11 with the rotation of the rotating device 40, the eddy current sensor 20 and the distance measuring sensor 50 can be positioned at any location in the space above the carrier disk 30.

[0091] Figure 7 A flowchart of a method 700 for acquiring a target output signal and a target lift-off height according to an embodiment of the present disclosure is shown. Figure 7As shown, the method 700 includes:

[0092] Step 710: Using a driving device, the eddy current sensor 20 and the ranging sensor 50 are moved along a preset path to multiple test positions relative to the wafer to be tested; and

[0093] Step 720: At each of the multiple test locations, acquire the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the ranging sensor 50, respectively, to determine the thickness of the metal thin film of the wafer under test at each of the multiple test locations.

[0094] Since the thickness of the metal film on a wafer is not uniform, or rather, the metal film may have different thicknesses at different locations, the locations on the wafer where the thickness needs to be measured must first be determined when measuring the thickness. In some embodiments, in order to detect the overall morphology of the metal film on the wafer, the thickness of the metal film at multiple different locations can be measured sequentially, and then the overall thickness of the metal film can be derived or simulated using relevant calculation software. In step 710, the eddy current sensor 20 and the ranging sensor 50 can be moved to multiple test locations relative to the wafer to be tested along a preset path. In step 720, at each test location, the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the ranging sensor 50 are acquired respectively, thereby obtaining a set of relevant data for multiple test locations. Subsequently, the thickness of the metal film at each test location can be calculated based on the relevant data.

[0095] In some embodiments, the preset path includes: a straight path on a horizontal plane that coincides with the diameter of the wafer to be tested; and / or a circumferential path on a horizontal plane with the center of the wafer to be tested as the center. Figure 8 A schematic diagram of a preset path according to an embodiment of the present disclosure is shown. Figure 8 Solid lines in the diagram represent the edges of the wafer, while dashed lines represent possible preset paths. Figure 8Two preset paths are shown. Path a coincides with the diameter of the wafer to be tested. When path a is selected, the rotating device 40 remains stationary, and only the swing arm 10 drives the eddy current sensor 20 and the distance sensor 50 to move above the carrier disk 30 along the direction of the diameter of the carrier disk 30. In this case, the measuring instrument 100 can measure relevant data of multiple positions to be measured on the wafer diameter. Path b coincides with a concentric circle of the wafer to be tested. When path b is selected, the swing arm 10 remains stationary, and only the rotating device 40 drives the carrier disk 30 to rotate. In this case, the measuring instrument 100 can measure relevant data of multiple positions to be measured on the concentric circle of the wafer. In other embodiments, the preset path can also be other more complex motion paths, and the positions to be measured are multiple points on the motion path. It is understood that regardless of the shape of the preset path, the eddy current sensor 20 and the distance sensor 50 can be moved along the path by controlling the drive components.

[0096] In some embodiments, the measuring instrument 100 further includes an in-situ sensor 60. The in-situ sensor 60 is configured to detect the position of a notch on the wafer to be inspected as the rotating device 40 drives the carrier disk 30 to rotate. Figure 9 A longitudinal cross-sectional schematic diagram of a measuring instrument 100 according to an embodiment of the present disclosure is shown. The position of the in-situ sensor 60 is configured to align with the notch on the wafer in the radial direction of the wafer to enable the detection of the wafer notch. Figure 9 As shown, the in-situ sensor 60 can be a through-beam in-situ sensor 60, which has a transmitter and a receiver. The transmitter emits red or infrared light, and the receiver receives the light emitted by the transmitter. When the wafer is between the transmitter and receiver, light transmission is cut off, and the receiver cannot receive the light signal. However, when the notch of the wafer passes between the two, the receiver can receive the light signal, and the in-situ sensor 60 outputs a detection signal. Therefore, when the wafer rotates until its notch reaches the position of the in-situ sensor 60, the trigger switch of the in-situ sensor 60 is triggered. The relevant processor of the measuring instrument 100 is configured to determine the current rotation position of the wafer to be detected based on the detection result of the in-situ sensor for the notch, so as to set the drive assembly to drive the eddy current sensor 20 and the distance sensor 50 to move along a preset path. For example, during the wafer rotation, the relevant processor can record the rotation angle of the carrier disk 30 within a certain time period, so as to determine the current rotation position of the wafer based on the time when the in-situ sensor detects the notch and the rotation angle of the carrier disk 30 after that time. By referencing the rotational position of the wafer at various times, and combining the rotation of the carrier disk 30 and the radial movement of the swing arm 10, the eddy current sensor 20 and the wafer can move relative to each other along the aforementioned preset path.

[0097] In some embodiments, edge compensation algorithms are used to correct data for edge measurements of the metal thin film on a wafer. Eddy current measurements generate eddy current magnetic fields, which exist within a certain area on the surface of the metal thin film. Therefore, the final measured thickness value is essentially the average thickness of a certain area on the surface of the metal thin film where the eddy current effect occurs. Furthermore, during the process of the sensor's magnetic field projection completely entering the wafer, some of the magnetic field is projected outside the wafer, resulting in magnetic field attenuation and causing measurement deviations at the wafer edge. On the other hand, according to measured data, comparing the eddy current measurement data with the actual metal thin film thickness model of the wafer reveals a certain shrinkage phenomenon. An edge attenuation model is established based on the measured data, and the measured film thickness information is corrected within a threshold distance range from the edge. This threshold distance range can be, for example, 5 mm, 10 mm, 15 mm, etc.

[0098] The aforementioned corrections include: correcting the coordinates of the position to be measured; and / or correcting the thickness measurement value corresponding to the position to be measured. For example, the coordinate information of the position to be measured corresponding to the thickness measurement can be corrected in advance, changing (r, θ, T) to (r + Δr, θ, T), where r and θ are the coordinates of the position to be measured in polar coordinates, and T is the thickness measurement; or the measurement value obtained from the position to be measured can be compensated and corrected, changing (r, θ, T) to (r, θ, T + ΔT).

[0099] Figure 10 This diagram illustrates a 2D graphical display of the thickness of a metal thin film on a wafer under inspection, wherein... Figure 10 The horizontal axis represents the radial coordinate r of the measured position, and the vertical axis represents the thickness measurement value of the measured position. In some embodiments, the above-mentioned correction of the coordinates of the measured position includes: for each measured position: keeping the thickness measurement value corresponding to the measured position unchanged, and increasing the coordinate value of the measured position, wherein the increase in the coordinate value of the measured position near the edge of the wafer to be tested is greater than the increase in the coordinate value of the measured position far from the edge of the wafer to be tested. Specifically, as shown in... Figure 10 As shown, curve 1 represents the thickness measurement value of the metal thin film obtained by contact measurement methods such as four-probe measurement. Due to the contact measurement method, curve 1 is close to the true value of the metal thin film thickness. Curve 2 represents the thickness measurement value obtained using the method of this disclosure but without edge compensation. Curve 3 represents the thickness measurement value obtained using the method of this disclosure and with edge compensation. In this embodiment, the radial coordinate of each measurement position is compensated, that is, the data (r, θ, T) of each measurement position is corrected to (r + Δr, θ, T). This compensation can be understood as adjusting curve 2 in... Figure 10 The horizontal axis was stretched to obtain curve 3.

[0100] In other embodiments, the correction of the thickness measurement value corresponding to the measured position includes: for each measured position: keeping the coordinates of the measured position unchanged, increasing the thickness measurement value corresponding to the measured position, wherein the increase in the thickness measurement value of the measured position closer to the edge of the wafer to be tested is greater than the increase in the thickness measurement value of the measured position farther from the edge of the wafer to be tested. Continuing to refer to... Figure 10 As shown, in these embodiments, the radial coordinates of each measured position are compensated, that is, the data (r, θ, T) of each measured position is corrected to (r, θ, T + ΔT). This compensation can be understood as adjusting the edge portion of curve 2. Figure 10 The vertical axis was lifted to obtain curve 3.

[0101] Although the above embodiments illustrate two different correction methods, in other embodiments, both methods can be used simultaneously, i.e., coordinate correction and thickness measurement value correction can be performed concurrently. For example... Figure 10 As shown, the corrected curve 3 is closer to the true curve (i.e., curve 1) than the uncorrected curve 2.

[0102] After measuring the thickness of the metal film at multiple test locations, the thickness of the metal film at each location on the wafer can be calculated or derived. Then, the average thickness, maximum value, minimum value, standard deviation, and other data of the metal film within the statistical radius of the wafer can be calculated and displayed in 2D or 3D graphics. Figure 11 This diagram illustrates a 3D graphical display of the thickness of a metal thin film on a wafer to be inspected.

[0103] According to another aspect of this disclosure, a measuring instrument 100 for measuring the thickness of a wafer metal thin film is also provided, comprising: a carrier disk 30 for carrying a wafer, wherein the upper surface of the wafer is covered with a metal thin film; an eddy current sensor 20 disposed above the carrier disk 30, configured to excite an eddy current magnetic field within the metal thin film of the wafer using the eddy current effect, and to detect the intensity of the eddy current magnetic field to generate a corresponding output signal; a distance sensor 50 disposed above the carrier disk 30 for measuring the lift-off height of the eddy current sensor 20 from the wafer; and a processor communicatively connected to the eddy current sensor 20 and the distance sensor 50, configured to, when the carrier disk 30 carries the wafer to be tested, acquire the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the distance sensor 50, respectively; and to determine the thickness of the metal thin film of the wafer to be tested based on the target output signal and the target lift-off height. The processor of the measuring instrument 100 can communicate with other components of the measuring instrument 100 for controlling these components or acquiring data generated by these components. For a description of each component in the measuring instrument 100, please refer to the description of... Figure 1 The description will not be repeated here.

[0104] In some embodiments, the processor is further configured to: determine a first mapping relationship between the thickness of the metal thin film on the wafer and the output signal of the eddy current sensor 20 when the lift-off height measured by the ranging sensor 50 is a preset standard height, wherein the coefficients in the first mapping relationship are related to the resolution of the eddy current sensor 20; determine a second mapping relationship between the lift-off height and the resolution of the eddy current sensor 20; correct the coefficients in the first mapping relationship according to the second mapping relationship to obtain a third mapping relationship between the thickness of the metal thin film on the wafer and the output signal of the eddy current sensor 20 when the lift-off height measured by the ranging sensor 50 is a target lift-off height; and determine the thickness of the metal thin film on the wafer to be tested based on the third mapping relationship according to the target output signal.

[0105] In some embodiments, the processor is further configured to: after the eddy current sensor 20 is adjusted to a standard height position, use the eddy current sensor 20 to detect multiple sample wafers in the sample wafer set to obtain the output signal of the eddy current sensor 20 corresponding to each of the multiple sample wafers, wherein the upper surface of each sample wafer in the sample wafer set is covered with a metal thin film of different thicknesses and known thickness; and fit a first mapping relationship according to the thickness of each sample wafer in the multiple sample wafers and the output signal of the eddy current sensor 20 corresponding to that sample wafer.

[0106] In some embodiments, the processor is further configured to: sequentially adjust the eddy current sensor 20 to a position at each of a plurality of sample heights; at each sample height position: detect each sample wafer in the sample wafer set using the eddy current sensor 20 to obtain an output signal of the eddy current sensor 20 corresponding to each sample wafer at that sample height position; determine the resolution of the eddy current sensor 20 at that sample height based on the thickness of each sample wafer in the sample wafer set and the output signal of the eddy current sensor 20 corresponding to each sample wafer at that sample height; and determine a second mapping relationship based on the plurality of sample heights and the resolution of the eddy current sensor 20 corresponding to each of the plurality of sample heights.

[0107] In some embodiments, the measuring instrument 100 further includes a driving component configured to drive the eddy current sensor 20 and the distance sensor 50 to move relative to the carrier disk 30, wherein the processor is further configured to: use the driving component to move the eddy current sensor 20 and the distance sensor 50 to a plurality of test positions along a preset path relative to the wafer to be tested; and at each of the plurality of test positions, acquire the target output signal generated by the eddy current sensor 20 and the target lift-off height measured by the distance sensor 50, respectively, for determining the thickness of the metal thin film of the wafer to be tested at each of the plurality of test positions.

[0108] According to one aspect of this disclosure, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory. The processor is configured to execute the computer program to implement the steps of any of the method embodiments described above.

[0109] According to one aspect of this disclosure, a non-transitory computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps of any of the method embodiments described above.

[0110] According to one aspect of this disclosure, a computer program product is provided, comprising a computer program that, when executed by a processor, implements the steps of any of the method embodiments described above.

[0111] In the following text, combined with Figure 12 Illustrative examples describing such electronic devices, non-transitory computer-readable storage media, and computer program products.

[0112] Figure 12 An example configuration of an electronic device 1200 that can be used to implement the methods described herein is shown. For example, the aforementioned measuring instrument 120 for wafer metal thin film thickness may include an architecture similar to that of the electronic device 1200, or may be implemented wholly or at least partially by the electronic device 1200 or similar devices or systems.

[0113] Electronic device 1200 may include at least one processor 1202, memory 1204, multiple communication interfaces 1206, display device 1208, other input / output (I / O) devices 1210, and one or more mass storage devices 1212 capable of communicating with each other, such as via system bus 1214 or other suitable connections.

[0114] Processor 1202 may be a single processing unit or multiple processing units, and all processing units may include single or multiple computing units or multiple cores. Processor 1202 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuits, and / or any device that manipulates signals based on operating instructions. Among other capabilities, processor 1202 may be configured to acquire and execute computer-readable instructions stored in memory 1204, mass storage device 1212, or other computer-readable media, such as program code of operating system 1216, program code of application program 1218, program code of other program 1220, etc.

[0115] Memory 1204 and mass storage device 1212 are examples of computer-readable storage media for storing instructions that are executed by processor 1202 to perform the various functions described above. For example, memory 1204 may generally include both volatile and non-volatile memory (e.g., RAM, ROM, etc.). Furthermore, mass storage device 1212 may generally include hard disk drives, solid-state drives, removable media, including external and removable drives, memory cards, flash memory, floppy disks, optical disks (e.g., CDs, DVDs), storage arrays, network-attached storage, storage area networks, etc. Memory 1204 and mass storage device 1212 may be collectively referred to herein as memory or computer-readable storage media, and may be non-transitory media capable of storing computer-readable, processor-executable program instructions as computer program code, which may be executed by processor 1202 as a specific machine configured to perform the operations and functions described in the examples herein.

[0116] Multiple programs may be stored on mass storage device 1212. These programs include operating system 1216, one or more application programs 1218, other programs 1220, and program data 1222, and they may be loaded into memory 1204 for execution. Examples of such application programs or program modules may include, for example, computer program logic (e.g., computer program code or instructions) for implementing components / functions such as methods 120 to 600 (including any suitable steps of the methods), and / or other embodiments described herein.

[0117] Although Figure 12The modules 1216, 1218, 1220, and 1222, or portions thereof, are illustrated as being stored in memory 1204 of electronic device 1200; however, modules 1216, 1218, 1220, and 1222, or portions thereof, may be implemented using any form of computer-readable medium accessible by electronic device 1200. As used herein, “computer-readable medium” includes at least two types of computer-readable media: computer-readable storage media and communication media.

[0118] Computer-readable storage media include volatile and non-volatile, removable and non-removable media implemented by any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Computer-readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, DVD, or other optical storage devices, magnetic cassettes, magnetic tapes, disk storage devices or other magnetic storage devices, or any other non-transmission medium that can be used to store information for access by electronic devices. In contrast, communication media can embody computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms. Computer-readable storage media as defined herein do not include communication media.

[0119] One or more communication interfaces 1206 are used for exchanging data with other devices, such as via a network, direct connection, etc. Such communication interfaces can be one or more of the following: any type of network interface (e.g., a network interface card (NIC)), wired or wireless (such as IEEE 802.11 Wireless LAN (WLAN)) wireless interface, Wi-MAX interface, Ethernet interface, Universal Serial Bus (USB) interface, cellular network interface, Bluetooth. TM Interfaces include near-field communication (NFC) interfaces. Communication interface 1206 facilitates communication across various network and protocol types, including wired networks (e.g., LAN, cable, etc.) and wireless networks (e.g., WLAN, cellular, satellite, etc.), the Internet, etc. Communication interface 1206 can also provide communication with external storage devices (not shown) such as storage arrays, network-attached storage, storage area networks, etc.

[0120] In some examples, a display device 1208, such as a monitor, may be included for displaying information and images to the user. Other I / O devices 1210 may be devices that receive various inputs from the user and provide various outputs to the user, and may include touch input devices, gesture input devices, cameras, keyboards, remote controls, mice, printers, audio input / output devices, and so on.

[0121] The technologies described herein can be supported by these various configurations of electronic device 1200, and are not limited to specific examples of the technologies described herein. For example, the functionality can also be implemented wholly or partially on a “cloud” using a distributed system. A cloud includes and / or represents a platform for resources. The platform abstracts the underlying functionality of the cloud’s hardware (e.g., servers) and software resources. Resources may include applications and / or data that can be used when performing computational processing on a server remote from electronic device 1200. Resources may also include services provided via the Internet and / or via subscriber networks such as cellular or Wi-Fi networks. The platform can abstract resources and functionality to connect electronic device 1200 to other electronic devices. Therefore, the implementation of the functionality described herein can be distributed throughout the cloud. For example, the functionality can be implemented partly on electronic device 1200 and partly through the platform that abstracts the functionality of the cloud.

[0122] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. A method for measuring the thickness of a metal thin film on a wafer, wherein, The measurement method is used in a wafer metal thin film thickness measuring instrument. The measuring instrument includes: a support disk for supporting a wafer, wherein the upper surface of the wafer is covered with a metal thin film; an eddy current sensor disposed above the support disk, configured to generate an eddy current magnetic field within the metal thin film of the wafer using the eddy current effect, and to detect the intensity of the eddy current magnetic field to generate a corresponding output signal; and a distance sensor disposed above the support disk for measuring the lift-off height of the eddy current sensor from the wafer. The measurement method includes: When the wafer to be tested is carried on the carrier disk, the target output signal generated by the eddy current sensor and the target lift-off height measured by the ranging sensor are acquired at multiple test positions respectively, so as to determine the thickness of the metal film of the wafer to be tested at each of the multiple test positions. The multiple test positions include multiple positions whose distance from the edge of the wafer to be tested is within a threshold distance range. Data correction is performed on multiple test locations and their corresponding measured thicknesses to determine the thickness of the metal film; The determination of the thickness of the metal thin film of the wafer under test at each of the plurality of test locations includes: When the lift-off height measured by the ranging sensor is determined to be a preset standard height, a first mapping relationship is established between the thickness of the metal thin film on the wafer and the output signal of the eddy current sensor, wherein the coefficients in the first mapping relationship are related to the resolution of the eddy current sensor. Determine a second mapping relationship between the lift-off height and the resolution of the eddy current sensor; The coefficients in the first mapping relationship are corrected according to the second mapping relationship to obtain a third mapping relationship between the thickness of the metal thin film on the wafer and the output signal of the eddy current sensor, when the lift-off height measured by the ranging sensor is the target lift-off height; and Based on the target output signal, the thickness at each measurement location is determined according to the third mapping relationship.

2. The measurement method according to claim 1, wherein, When the lift-off height measured by the ranging sensor is determined to be a preset standard height, the first mapping relationship between the thickness of the metal thin film on the wafer and the output signal of the eddy current sensor includes: Once the eddy current sensor is adjusted to the standard height position, it is used to detect multiple sample wafers in the sample wafer set to obtain the output signal of the eddy current sensor corresponding to each of the multiple sample wafers. Each sample wafer in the sample wafer set has its upper surface covered with a metal thin film of varying and known thickness. The first mapping relationship is fitted based on the thickness of each of the plurality of sample wafers and the output signal of the eddy current sensor corresponding to that sample wafer.

3. The measurement method according to claim 2, wherein, Determining the second mapping relationship between the lift-off height and the resolution of the eddy current sensor includes: The eddy current sensor is sequentially adjusted to the position of each of the multiple sample heights, at each sample height position: The eddy current sensor is used to detect each sample wafer in the sample wafer set to obtain the output signal of the eddy current sensor corresponding to each sample wafer at a position of that sample height; and The resolution of the eddy current sensor at the sample height is determined based on the thickness of each sample wafer in the sample wafer set and the output signal of the eddy current sensor corresponding to each sample wafer at that sample height; and The second mapping relationship is determined based on the plurality of sample heights and the resolution of the eddy current sensor corresponding to each of the plurality of sample heights.

4. The measurement method according to any one of claims 1-3, wherein, The measuring instrument also includes a driving component configured to drive the eddy current sensor and the distance sensor to move relative to the carrier disk. When the carrier disk carries the wafer to be tested, the driving component is used to move the eddy current sensor and the distance sensor to multiple test positions relative to the wafer to be tested along a preset path.

5. The measurement method according to claim 4, wherein the data correction includes: Correct the coordinates of the position to be measured; and / or Correct the thickness measurement value corresponding to the position to be measured.

6. The measurement method according to claim 5, wherein, Correcting the coordinates of the location to be measured includes: For each test location: keep the thickness measurement value corresponding to the test location unchanged, and increase the coordinate value of the test location. The increase in the coordinate value of the test location closer to the edge of the wafer to be tested is greater than the increase in the coordinate value of the test location farther away from the edge of the wafer to be tested.

7. The measurement method according to claim 5, wherein, Correcting the thickness measurement value corresponding to the location to be measured includes: For each test location: keep the coordinates of the test location unchanged, and increase the thickness measurement value corresponding to the test location. The increase in the thickness measurement value of the test location closer to the edge of the wafer to be tested is greater than the increase in the thickness measurement value of the test location farther away from the edge of the wafer to be tested.

8. An instrument for measuring the thickness of a thin metal film on a wafer, comprising: A carrier disk for holding a wafer, wherein the upper surface of the wafer is covered with a thin metal film; An eddy current sensor is disposed above the carrier disk and configured to generate an eddy current magnetic field within the metal thin film of the wafer using the eddy current effect, and to detect the intensity of the eddy current magnetic field to generate a corresponding output signal. A ranging sensor, positioned above the carrier disk, is used to measure the lift-off height of the eddy current sensor from the wafer; and The processor, communicatively connected to the eddy current sensor and the ranging sensor, is configured to acquire, at multiple test locations, the target output signal generated by the eddy current sensor and the target lift-off height measured by the ranging sensor when the wafer to be tested is carried on the carrier disk. This is used to determine the thickness of the metal film of the wafer to be tested at each of the multiple test locations, including multiple locations whose distance from the edge of the wafer to be tested is within a threshold distance range. Data correction is performed on the multiple test locations and their corresponding measured thicknesses to determine the thickness of the metal film. The processor is further configured to: When the lift-off height measured by the ranging sensor is determined to be a preset standard height, a first mapping relationship is established between the thickness of the metal thin film on the wafer and the output signal of the eddy current sensor, wherein the coefficients in the first mapping relationship are related to the resolution of the eddy current sensor. Determine a second mapping relationship between the lift-off height and the resolution of the eddy current sensor; The coefficients in the first mapping relationship are corrected according to the second mapping relationship to obtain a third mapping relationship between the thickness of the metal thin film on the wafer and the output signal of the eddy current sensor, when the lift-off height measured by the ranging sensor is the target lift-off height; and Based on the target output signal, the thickness at each measurement location is determined according to the third mapping relationship.

9. An electronic device, comprising: At least one processor; as well as At least one memory on which a computer program is stored, When the computer program is executed by the at least one processor, it causes the at least one processor to perform the measurement method according to any one of claims 1 to 7.

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