Method, device, equipment and medium for measuring thickness of metal film on wafer

Abstract

The embodiments of the present application provide a method, device, polishing equipment and storage medium for measuring the thickness of a metal film on a wafer during a polishing process. The method for measuring the thickness of a metal film on a wafer during a polishing process includes: obtaining a current temperature and a current measurement signal; wherein the current temperature is used to indicate the temperature of the metal film on the wafer at the current moment; the current measurement signal is collected by an eddy current sensor, and the current measurement signal is related to the thickness of the metal film; the measured thickness of the metal film is determined according to the current measurement signal; the measured thickness is corrected according to the current temperature and temperature correction information to obtain the thickness of the metal film; the temperature correction information is used to indicate the relationship between the current temperature, the measured thickness and the thickness of the metal film.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of semiconductor manufacturing technology, and in particular, to a method, device, equipment and medium for measuring the thickness of a metal film on a wafer. Background Art

[0002] When performing chemical mechanical polishing on a wafer, it is usually necessary to measure the thickness of the metal film on the wafer surface through an eddy current sensor. When the thickness of the metal film reaches a preset value, a correct signal is given to terminate the chemical mechanical polishing process, thereby ensuring the polishing accuracy.

[0003] The chemical mechanical polishing process includes chemical and mechanical polishing. Specifically, there is a chemical reaction between the polishing liquid and the wafer, and there is a mechanical reaction between the polishing liquid, polishing pad and polishing head and the wafer. Both chemical and mechanical reactions will cause the temperature of the wafer to rise sharply, causing the resistivity of the metal film on the wafer to change, which in turn affects the accuracy of the eddy current sensor in measuring the thickness of the metal film. Summary of the invention

[0004] In view of this, embodiments of the present application provide a method, device, equipment and medium for measuring the thickness of a metal film on a wafer, so as to at least partially solve the above-mentioned problems.

[0005] According to a first aspect of an embodiment of the present application, a method for measuring the thickness of a metal film on a wafer during a polishing process is provided, comprising: obtaining a current temperature and a current measurement signal; wherein the current temperature is used to indicate the temperature of the metal film on the wafer at the current moment; the current measurement signal is collected by an eddy current sensor, and the current measurement signal is related to the thickness of the metal film; determining the measured thickness of the metal film according to the current measurement signal; correcting the measured thickness according to the current temperature and temperature correction information to obtain the thickness of the metal film; the temperature correction information is used to indicate the relationship between the current temperature, the measured thickness and the thickness of the metal film.

[0006] According to a second aspect of an embodiment of the present application, a device for measuring the thickness of a metal film on a wafer during a polishing process is provided, comprising: an acquisition unit, for acquiring a current temperature and a current measurement signal; wherein the current temperature is used to indicate the temperature of the metal film on the wafer at the current moment; the current measurement signal is collected by an eddy current sensor, and the current measurement signal is related to the thickness of the metal film; a measurement thickness determination unit, for determining the measured thickness of the metal film according to the current measurement signal; a correction unit, for correcting the measured thickness according to the current temperature and temperature correction information to obtain the thickness of the metal film; the temperature correction information is used to indicate the relationship between the current temperature, the measured thickness and the thickness of the metal film.

[0007] According to a third aspect of an embodiment of the present application, a chemical mechanical polishing device is provided, comprising: a polishing disk, a carrying head, a liquid supply device, an eddy current sensor, a controller and a temperature sensor; the carrying head loads a wafer to be polished and abuts it against a polishing pad above the polishing disk, and the liquid supply device supplies polishing liquid toward between the polishing pad and the wafer; the eddy current sensor is used to collect a current measurement signal; the temperature sensor is used to detect a current temperature, and the controller is used to perform the following steps: obtaining a current temperature and a current measurement signal; wherein the current temperature is used to indicate the temperature of a metal film of the wafer at the current moment; the current measurement signal is collected by the eddy current sensor, and the current measurement signal is related to the thickness of the metal film; determining the measured thickness of the metal film according to the current measurement signal; correcting the measured thickness according to the current temperature and temperature correction information to obtain the thickness of the metal film; the temperature correction information is used to indicate the relationship between the current temperature, the measured thickness and the thickness of the metal film.

[0008] According to a fourth aspect of the embodiments of the present application, a computer storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the method described in any of the above embodiments is implemented.

[0009] In the embodiment of the present application, the temperature variation difference of the metal film can be determined according to the current temperature and the initial temperature, and the measured thickness can be corrected according to the temperature variation difference and the temperature correction information to obtain the thickness of the metal film. Among them, the temperature variation difference of the metal film can be determined according to the current temperature and the initial temperature, and the temperature variation of the metal film during the polishing process of the wafer can be obtained, and the temperature correction information can indicate the relationship between the temperature variation difference, the measured thickness and the thickness of the metal film. It can be seen that the error of the measured thickness caused by the temperature variation during the polishing process of the metal film of the wafer can be corrected according to the temperature variation difference and the temperature correction information. Compared with a single temperature, such as the current temperature, the temperature variation can reflect the temperature variation during the polishing process, that is, the temperature variation difference is closer to the temperature condition of the polishing process. Therefore, the error of the measured thickness caused by the temperature variation can be more accurately compensated by correcting the measured thickness according to the temperature variation difference, compared with correcting the measured thickness according to a single temperature value, and the effect of correcting the measured thickness can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0011] Figure 1 It is a schematic diagram of the structure of a chemical mechanical polishing device;

[0012] Figure 2 It is a schematic diagram of the correlation between the signal value of the measurement signal of the eddy current sensor and the measured thickness;

[0013] Figure 3 It is a flowchart of the steps of a method for measuring the thickness of a metal film on a wafer during a polishing process provided by an optional embodiment of the present application;

[0014] Figure 4 is a structural schematic diagram of a chemical mechanical polishing device provided in an optional embodiment of the present application;

[0015] Figure 5 This is a flowchart of another method for measuring the thickness of a metal film on a wafer during a polishing process provided by an optional embodiment of the present application;

[0016] Figure 6 It is a curve fitting schematic diagram provided by an optional embodiment of the present application;

[0017] Figure 7 is a measured data coordinate diagram provided by an optional embodiment of the present application;

[0018] Figure 8 This is a structural block diagram of a device for measuring the thickness of a metal film on a wafer during a polishing process provided in an optional embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the embodiments of the present application should fall within the scope of protection of the embodiments of the present application.

[0020] According to a first aspect of an embodiment of the present application, a method for measuring the thickness of a metal film on a wafer during a polishing process is provided to solve the above-mentioned problem.

[0021] The method provided in the embodiment of the present application can be used to measure the thickness of the metal film on the wafer when the chemical mechanical polishing equipment polishes the metal film on the wafer. It should be understood that chemical mechanical polishing (CMP) is a global flattening ultra-precision surface processing technology that can complete the chemical mechanical polishing of the wafer under the combined action of chemistry and mechanics. It should be noted that the polishing of the wafer recorded in the embodiment of the present application is to polish the metal film of the wafer.

[0022] like Figure 1 As shown, the chemical mechanical polishing equipment 10 may include a polishing disk 11, a carrier head 12, an eddy current sensor 13, a polishing pad 14, a controller 15 and a liquid supply device 16. Among them, the carrier head 12 can adsorb the wafer to be polished, and abut the metal film on the wafer against the polishing pad 14 above the polishing disk 11. The liquid supply device 16 supplies polishing liquid between the polishing pad 14 and the wafer. The eddy current sensor 13 is used to collect the corresponding measurement signal when measuring the thickness of the metal film of the wafer. The controller 15 is used to control the process of measuring the thickness of the metal film of the wafer. The method for measuring the thickness of the metal film of the wafer during the polishing process provided in the embodiment of the present application can be used for the controller 15, so that it performs the process of measuring the thickness of the metal film of the wafer during the polishing process.

[0023] The eddy current sensor can form an induced eddy current in the conductive layer of the wafer through a high-frequency oscillation circuit. The induced eddy current will form an alternating magnetic field opposite to the eddy current sensor and feed back to the sensor, so that the eddy current sensor can collect the corresponding measurement signal. When other conditions remain unchanged, there is a one-to-one correspondence between the measurement signal detected by the eddy current sensor and the thickness of the metal film. In the embodiment of the present application, the thickness of the metal film indicated by the measurement signal is used as the measured thickness of the metal film. It should be noted that the relationship between the signal value of the measurement signal and the measured thickness of the metal film is generally: Figure 2 The linear relationship shown in 201 can be used to map the measurement signal to the measured thickness.

[0024] When polishing the metal film on the wafer, due to the violent mechanical and chemical effects, the temperature of the metal film will rise sharply, and the free-moving electrons in the metal film will vibrate back and forth rapidly, thereby hindering the flow of induced eddy currents in the metal film, making the measured thickness of the metal film measured by the eddy current sensor smaller, resulting in the actual thickness of the metal film being greater than the target thickness when the measured thickness reaches the target thickness. If the wafer is stopped from being polished at this time, an excessively thick metal film will remain on the wafer. The method for measuring the thickness of the metal film on the wafer during the polishing process provided in the embodiment of the present application can solve this problem. Figure 3-7The method provided in the embodiments of the present application is described in detail.

[0025] like Figure 3 As shown, the embodiment of the present application provides a method for measuring the thickness of a metal film on a wafer during a polishing process, comprising:

[0026] S310: Acquire the current temperature and the current measurement signal; wherein the current temperature is used to indicate the temperature of the metal film of the wafer at the current moment; the current measurement signal is collected by the eddy current sensor, and the current measurement signal is related to the thickness of the metal film.

[0027] like Figure 4 As shown, the chemical mechanical polishing device 10 using the method of the embodiment of the present application may also include a temperature sensor 17, such as a non-contact temperature sensor 17 such as an infrared temperature sensor, or other contact temperature sensors. The current temperature of the metal film of the wafer can be measured by the temperature sensor 17. It should be noted that the measurement signal collected by the eddy current sensor can be used to determine the measured thickness of the metal film of the wafer, and the current measurement signal is the measurement signal currently collected by the eddy current sensor.

[0028] S320: Determine the measured thickness of the metal film according to the current measurement signal.

[0029] After obtaining the current measurement signal, the current measurement signal can be mapped to the corresponding measurement thickness according to the known correlation between the eddy current measurement signal and the measured thickness of the metal film.

[0030] S330: Correcting the measured thickness according to the current temperature and the temperature correction information to obtain the thickness of the metal film; the temperature correction information is used to indicate the relationship between the current temperature, the measured thickness and the thickness of the metal film.

[0031] The temperature correction information may be a relationship function representing the relationship between the current temperature, the measured thickness, and the (actual) thickness of the metal film. The temperature correction information may be obtained by function fitting using multiple sets of measured thicknesses, actual thicknesses, and corresponding current temperatures of the metal film as sample data, or may be obtained by other methods, all of which are within the scope of protection of the embodiments of the present application.

[0032] Since the temperature correction information can indicate the relationship between the current temperature, measured thickness and the thickness of the metal film, the temperature correction information can be used to determine the thickness of the metal film corresponding to the measured thickness of the metal film at the current temperature based on the current temperature and measured thickness, thereby correcting the measured thickness.

[0033] The method for measuring the thickness of a metal film on a wafer provided in the embodiment of the present application can obtain the current temperature of the wafer and the current measurement signal collected by the eddy current sensor, and determine the measured thickness of the metal film according to the current measurement signal. The measured thickness can also be corrected according to the current temperature and predetermined temperature correction information, compensating for the thickness measurement error caused by the change in resistivity of the metal film on the wafer caused by the change in wafer temperature, and obtaining a more accurate thickness of the metal film, thereby improving the accuracy of measuring the thickness of the metal film.

[0034] In some optional embodiments, the measured thickness is corrected according to the current temperature and temperature correction information to obtain the thickness of the metal film, including: determining the temperature change difference of the metal film according to the current temperature and the initial temperature, the initial temperature is used to indicate the temperature of the metal film when the metal film starts to be polished; correcting the measured thickness according to the temperature change difference and the temperature correction information to obtain the thickness of the metal film; wherein the temperature correction information is used to indicate the relationship between the temperature change difference, the measured thickness and the thickness of the metal film.

[0035] It should be understood that the process of polishing the metal film of the wafer is usually a continuous process, and the initial temperature is used to indicate the initial temperature of the metal film when the metal film of the wafer is polished. The temperature change difference is the difference between the current temperature of the metal film and the initial temperature.

[0036] In the method for measuring the thickness of a metal film on a wafer provided in an embodiment of the present application, the parameters in the temperature correction information may also include the initial temperature of the metal film, and the temperature change difference is represented by the difference between the current temperature and the initial temperature of the metal film, so that the relationship between the current temperature indicated by the temperature correction information, the measured thickness, and the thickness of the metal film can be specifically the relationship between the temperature change difference, the measured thickness, and the thickness of the metal film, so that the temperature correction information can fit the influence of the temperature change of the metal film of the wafer on the measurement of the thickness of the metal film through the temperature change difference.

[0037] It should be noted that during the polishing process of the metal film on the wafer, the temperature of the wafer usually continues to rise, so the temperature correction information indicating the relationship between the temperature change difference, the measured thickness and the thickness of the metal film can more accurately fit the relationship between the measured thickness and the (actual) thickness of the metal film during the polishing process.

[0038] The temperature correction information of this embodiment can indicate the relationship between the temperature change difference, the measured thickness and the thickness of the metal film. Therefore, the temperature correction information can be used to determine the thickness of the metal film corresponding to the measured thickness of the metal film under the current temperature conditions based on the temperature change difference and the measured thickness determined by the current temperature and the initial temperature, thereby realizing the correction of the measured thickness.

[0039] In the embodiment of the present application, the temperature variation difference of the metal film can be determined according to the current temperature and the initial temperature, and the measured thickness can be corrected according to the temperature variation difference and the temperature correction information to obtain the thickness of the metal film. Among them, the temperature variation difference of the metal film can be determined according to the current temperature and the initial temperature, and the temperature variation of the metal film during the polishing process of the wafer can be obtained, and the temperature correction information can indicate the relationship between the temperature variation difference, the measured thickness and the thickness of the metal film. It can be seen that the measured thickness can be corrected according to the temperature variation difference and the temperature correction information, and the error of the measured thickness caused by the temperature variation during the polishing process of the metal film of the wafer can be corrected. Compared with a single temperature, such as the current temperature, the temperature variation can reflect the temperature variation during the polishing process, that is, the temperature variation difference is closer to the temperature condition of the polishing process. Therefore, the correction of the measured thickness according to the temperature variation difference can more accurately compensate for the error of the measured thickness caused by the temperature variation, and improve the effect of correcting the measured thickness, compared with the correction of the measured thickness according to a single temperature value.

[0040] In some optional embodiments, the method provided in the present application further includes: comparing the thickness of the obtained metal film with the target thickness, and when the thickness of the metal film is less than or equal to the target thickness, terminating the polishing operation on the metal film.

[0041] The target thickness can be preset according to the user's requirements for the thickness of the metal film on the wafer. For example, the target thickness can be equal to the thickness of the metal film required by the user, or slightly less than / slightly greater than the thickness of the metal film required by the user, all within the protection scope of the embodiments of the present application.

[0042] In the process of polishing the metal film on the wafer, the embodiment of the present application can use the eddy current sensor to measure the metal film to obtain the measured thickness of the metal film, and the thickness of the metal film can be corrected to obtain the thickness of the metal film, and the polishing progress of the metal film on the wafer can be determined according to the obtained thickness of the metal film. And by comparing the obtained thickness of the metal film with the target thickness, the polishing of the metal film can be stopped when the thickness of the metal film reaches the target thickness, so as to accurately control the polishing process of the metal film on the wafer, thereby accurately completing the polishing of the metal film on the wafer.

[0043] In some optional embodiments, the method provided in the present application further includes: when the thickness of the obtained metal film is greater than the target thickness, controlling the polishing operation of the metal film according to the target thickness.

[0044] When the thickness of the obtained metal film is greater than the target thickness, the metal film of the wafer needs to be polished further. At this time, the polishing operation of the metal film can be controlled according to the thickness of the obtained metal film. For example, the polishing speed of the metal film of the wafer can be controlled according to the thickness of the obtained metal film to control the time for subsequent polishing of the metal film of the wafer. Alternatively, the polishing speed of the metal film of the wafer can be controlled according to the difference between the obtained thickness of the metal film and the target thickness. For example, as the difference between the obtained thickness of the metal film and the target thickness decreases, the polishing speed of the metal film of the wafer can be appropriately reduced. It should be understood that the polishing speed of the metal film of the wafer can be controlled by controlling the rotation speed of the carrier head and the polishing pad.

[0045] In an embodiment of the present application, the polishing progress of the metal film on the wafer can be determined based on the obtained thickness of the metal film. When the obtained thickness of the metal film is greater than the target thickness, the polishing operation on the metal film can be controlled based on the target thickness, such as increasing / decreasing the polishing speed, etc., thereby controlling the polishing process of the metal film on the wafer, making the control of the polishing of the metal film on the wafer more flexible.

[0046] In some optional embodiments, acquiring the current temperature and the current measurement signal includes: acquiring the current temperature of the polishing pad and the current measurement signal, and determining the current temperature of the polishing pad as the current temperature.

[0047] In the embodiment of the present application, the temperature of the polishing pad can be used as the temperature of the metal film being polished by the polishing pad. Specifically, when the metal film of the wafer is polished, the metal film of the wafer is in contact with the polishing pad, and the heat generated during the polishing process can be transferred between the metal film of the wafer and the polishing pad. By detecting the current temperature of the polishing pad, the current temperature of the metal film of the wafer can be indirectly measured. Similarly, the temperature of the polishing pad when the metal film of the wafer is polished can also be detected, and the temperature can be used as the initial temperature of the metal film of the wafer to indirectly measure the initial temperature of the metal film of the wafer.

[0048] According to the rotation direction of the polishing pad, the carrier head may include a front side and a rear side, wherein the front side is the side of the carrier head located in front of the polishing pad in the rotation direction, and the front side is the side of the carrier head located in the rear of the polishing pad in the rotation direction. As a feasible implementation, the temperature sensor 17 may be arranged on the rear side of the carrier head, and the polishing pad area corresponding to the rear side of the carrier head is the polishing pad area where the polishing pad just contacts the metal film of the wafer during the rotation process. The temperature of this polishing pad area is substantially the same as the metal film of the wafer, so the temperature of the metal film of the wafer may be indirectly detected by detecting the temperature of the polishing pad in this area. Of course, the temperature of the metal film of the wafer may also be detected by detecting the temperature of other suitable areas on the polishing pad, such as other areas on the polishing pad that contact the metal film of the wafer, or areas on the polishing pad that are adjacent to the areas that contact the metal film of the wafer.

[0049] In the embodiment of the present application, the current temperature of the metal film of the wafer can be indirectly measured by measuring the current temperature of the polishing pad. Compared with directly measuring the current temperature of the metal film of the wafer, the difficulty of measuring the current temperature can be significantly reduced, and the installation of a temperature sensor inside the carrier head that supports the wafer can be avoided, which is beneficial to reducing the structural complexity of the carrier head.

[0050] In some optional embodiments, the temperature correction information includes:

[0051] THK comp =(T(t)-T ini )*F(THK)+THK (1)

[0052] Among them, THK comp is used to indicate the thickness of the metal film, T(t) is used to indicate the current temperature, T ini Used to indicate the initial temperature, T(t)-T ini It is used to indicate the temperature change difference, THK is used to indicate the measured thickness, and F(THK) is used to indicate (THK comp -THK) and (T(t)-T ini ), and F(THK) is a function determined with THK as the independent variable.

[0053] Exemplarily, F(THK) can be a linear function, for example: F(THK)=m*(THK)+b. m and b are the linear term coefficient and intercept value, respectively. m and b can be obtained by function fitting using sample data including multiple groups of F(THK) values ​​and THK values, or by other methods, all within the protection scope of the embodiments of the present application. Of course, F(THK) can also be a function of other forms, including but not limited to polynomial functions, exponential functions, and logarithmic functions, etc., or the relationship between F(THK) and THK can be learned by machine learning to obtain the functional relationship between F(THK) and THK.

[0054] In the embodiment of the present application, by performing calculations on the above function (1) included in the temperature correction information, THK can be directly obtained. comp The value of is obtained, that is, the corrected thickness value of the metal film is obtained. The calculation process is simple and convenient, which is beneficial to saving computing resources and improving the efficiency of metal film thickness measurement.

[0055] like Figure 5 As shown, in some optional embodiments, the method provided by the present application further includes the step of obtaining the above function (1), specifically including:

[0056] S510: Use multiple wafers with different initial thicknesses of metal films as wafer samples, polish each wafer sample separately without adding polishing liquid, and obtain the temperature of the polishing pad and the sample measurement signal during the polishing process; use the temperature of the polishing pad as the sample temperature of the metal film of the polished wafer sample, and use the temperature of the polishing pad when polishing the wafer sample begins as the initial temperature corresponding to the metal film; determine the corresponding sample measurement thickness of the wafer sample based on the sample measurement signal.

[0057] In order to obtain the above function (1), multiple wafer samples can be prepared in advance, and at least some of the wafer samples have different initial thicknesses of the metal film. It should be noted that before polishing the metal film of the wafer, the initial temperature of the metal film of the wafer can be kept the same as the initial temperature of the polishing pad, and the surface of the polishing pad can be kept moist during the polishing process, and the temperature of the polishing disk can be kept stable. In the process of polishing the metal film of the wafer without adding a polishing liquid, the thickness of the metal film of the wafer can remain basically unchanged, that is, in the process of polishing the metal film of the wafer without adding a polishing liquid, it can be approximately considered that the actual thickness of the metal film of the wafer is equal to its initial thickness. Specifically, the supply of the polishing liquid can be turned off during the polishing process, and a carrier head can be set to abut the wafer sample against the polishing pad with a large pressure to ensure that only friction exists during the polishing process. It should be understood that the carrier head can apply the same pressure to each wafer sample to eliminate the influence of the pressure difference of the carrier head on the polishing process. During the polishing process of the wafer samples, the polishing time can be controlled to be the same so that the maximum temperature change of each wafer sample during the polishing process is the same or substantially the same, thereby ensuring the consistency of temperature change during the polishing process.

[0058] S520: Recording the initial temperature for polishing the metal film of each wafer sample and the sample measured thickness of each wafer sample at multiple sample temperatures.

[0059] S530: Determine F(THK) sample values ​​corresponding to the measured thicknesses of the multiple samples according to the initial temperature, the metal film thickness of the wafer sample, multiple sample temperatures, and the measured thicknesses of the samples at the multiple sample temperatures; wherein the metal film thickness of the wafer sample is equal to the initial thickness.

[0060] By polishing the wafer sample, sample data of the wafer sample during the polishing process can be obtained. The sample data of each wafer sample may include the initial temperature of the wafer sample during polishing, the metal film thickness of the wafer sample, the sample temperature obtained during the polishing process, and the sample measurement thickness corresponding to the sample temperature, etc. It should be understood that when polishing the wafer sample, sample temperatures at multiple moments and sample measurement signals corresponding to each sample temperature can be obtained, and multiple sample measurement thicknesses can be determined based on each sample measurement signal to expand the data volume of the sample data.

[0061] Assume that the initial temperature of the metal film of the i-th wafer sample is T ini-i , the metal film thickness / initial thickness of the i-th wafer sample is THK real-i , the sample temperature of the i-th wafer sample at time t is T i (t), the sample measurement thickness of the i-th wafer sample determined according to the sample measurement signal obtained at time t is THK cal-i (t), the sample thickness is THKcal-i (t) The corresponding F(THK) sample value can be F(THK cal-i (t)) = (THK real-i -THK cal-i (t)) / (T i (t)-T ini-i ). Where i is a positive integer and the value of i is not greater than the number of wafer samples.

[0062] As a feasible implementation method, the F(THK) sample value can also be determined by curve fitting, such as Figure 6 As shown, Figure 6 The horizontal axis is the difference between the (initial) thickness of the metal film of the wafer sample and the measured thickness of the sample. Figure 6 The ordinate is the difference between the sample temperature and the initial temperature of the polishing pad. Figure 6 The coordinate points indicated by 602, 604, 606, 608, 610, and 612 are sample points obtained during the polishing process of different wafer samples. The straight lines indicated by 601, 603, 605, 607, 609, and 611 are the straight lines fitted by the coordinate points indicated by 602, 604, 606, 608, 610, and 612. The inverse of the slope of the straight lines indicated by 601, 603, 605, 607, 609, and 611 is the F(THK) sample value.

[0063] Taking the i-th wafer sample as an example, the function relationship fitted by the curve fitting can be:

[0064] (THK real-i -THK cal-i (t)) = ki*(T i (t)-T ini-i ) (2)

[0065] Among them, ki is the parameter to be determined, that is, F(THK cal-i The fitted value of (t) can be understood as the slope of function (2).

[0066] Moreover, the function fitting can be performed with the minimum value of the objective function as the fitting termination condition. The objective function can be:

[0067] Among them, δ1 is used to indicate the error of the sample data fitting function (2), is used to indicate the function value of the objective function (3), and n is the number of sample data corresponding to the i-th wafer sample.

[0068] S540: Taking the sample measured thickness as an independent variable and the sample value of F (THK) corresponding to the sample measured thickness as a function value, determine a functional relationship of F (THK) in the temperature correction information.

[0069] F(THK) can be a linear function, a polynomial function, an exponential function, a logarithmic function, etc. Taking the case where the functional relationship of F(THK) fitting is a linear function, let the functional relationship of F(THK) be:

[0070] F(THK)=m*(THK)+b (4)

[0071] m and b are parameters to be determined. cal-i (t) is the sample value of THK, and F(THK cal-i (t)) is used as the sample value of F(THK), and the above function (4) is fitted to determine m and b.

[0072] Moreover, the function fitting can be performed with the minimum value of the objective function as the fitting termination condition. The objective function can be:

[0073] δ2 is used to indicate the error of the sample data fitting function (4), and is used to indicate the function value of the objective function (5).

[0074] In addition, without adding polishing liquid and with other conditions being the same, two wafers with the same metal film thickness were polished separately. Figure 7 The point indicated by 701 represents the measured thickness data collected during the first wafer polishing process. The ordinate of the point is the value of the measured thickness. Figure 7 The point indicated by 702 represents the metal film thickness data obtained by the method provided by the present application during the second wafer polishing process, and the ordinate of the point is the thickness value of the metal film corrected by the above method. It can be seen that the downward trend of the thickness of the metal film obtained by the method provided by the present application has been significantly alleviated compared with the measured thickness.

[0075] In an embodiment of the present application, by using multiple wafers with different initial thicknesses of metal films as wafer samples and polishing each wafer sample separately without adding polishing liquid, it can be approximately assumed that the actual thickness of the metal film during the polishing process of the metal film of the wafer is equal to its initial thickness. Therefore, there is no need to measure the actual thickness of the metal film on the wafer, thereby simplifying the complexity of obtaining sample data. During the polishing process, the polishing pad and sample measurement signals can be obtained; the temperature of the polishing pad is used as the sample temperature of the metal film of the wafer sample being polished, and the temperature of the polishing pad when the wafer sample is polished is used as the initial temperature corresponding to the metal film; and the initial temperature of each wafer sample polishing and the sample measurement thickness at multiple sample temperatures are recorded; according to the initial temperature, the metal film thickness of the wafer sample, multiple sample temperatures and the sample measurement thickness at multiple sample temperatures, the F(THK) sample values ​​corresponding to the multiple sample temperatures are determined; then the sample temperature is used as an independent variable, and the sample value of F(THK) corresponding to the sample temperature is used as a function value to determine the functional relationship of F(THK), and then the above function (1) is determined, so as to obtain temperature correction information for use, so that when measuring the thickness of the wafer metal film, the temperature correction information can be used to perform simple calculations to obtain (THK) comp value / thickness value of metal film), which is beneficial to saving computing resources and improving the efficiency of metal film thickness measurement.

[0076] like Figure 5 As shown, in some optional embodiments, the method provided by the present application further includes:

[0077] S340: Determine whether there is a water polishing stage during the polishing process of the metal film.

[0078] The water polishing stage is a polishing stage in which the supply of polishing liquid to the wafer is stopped and pure water is supplied to the wafer. Pure water is water without impurities and dissolved substances, and the pure water used can be deionized water, etc. Based on the relevant data of the supply of pure water, it can be determined whether there is a water polishing stage. For example, it can be determined whether there is a water polishing stage based on whether there is a control instruction to execute the supply of pure water; or it can be determined whether there is a water polishing stage based on the time information of the supply of pure water.

[0079] S350: If there is a water polishing stage, the water polishing measurement thickness of the metal film is determined according to the measurement signal collected during the water polishing stage, and the temperature correction information is adjusted according to the water polishing measurement thickness to obtain the adjusted temperature correction information.

[0080] During the water polishing stage, the temperature of the wafer metal film will gradually approach the temperature of pure water and gradually stabilize at a temperature close to the temperature of pure water. By detecting the temperature change of the metal film, it can be determined whether the temperature of the metal film is stable. For example, the temperature change of the metal film in a predetermined time interval is detected. If the temperature change is less than a predetermined threshold, it can be determined that the temperature of the wafer metal film is already in a stable state. As a feasible implementation method, the temperature of the polishing pad can be taken as the temperature of the wafer metal film to reduce the difficulty of obtaining the temperature of the metal film.

[0081] This embodiment can obtain the measurement signal collected by the eddy current sensor when the temperature of the metal film of the wafer is in a stable state during the water polishing stage, determine the water polishing measured thickness of the metal film according to the measurement signal, use the measured thickness as the metal film thickness, adjust the temperature correction information, and thus obtain the adjusted temperature correction information. It should be understood that if it is determined that there is a water polishing stage in the polishing process, the process of correcting the measured thickness can be omitted, and the metal film thickness in the water polishing stage can be directly determined as the water polishing measured thickness.

[0082] Exemplarily, the water-polished thickness of the metal film can be determined based on the measurement signal collected when the temperature of the metal film of the wafer is in a stable state during the water-polishing stage, and the water-polished thickness can be used as the thickness of the metal film. In addition, the start time of the water-polishing stage can be determined based on the time information of supplying pure water, and the measurement signal collected by the eddy current sensor at the start time of the water-polishing stage and the temperature of the metal film at the start time of the water-polishing stage can be obtained. The measurement signal can be used as the polishing sample measurement signal, and the temperature can be used as the polishing sample temperature; the corresponding measurement thickness can be determined based on the sample measurement signal, and the measurement thickness can be used as the polishing sample measurement thickness. In addition, the initial temperature of the metal film at the beginning of the non-water-polishing stage before the water-polishing stage can also be obtained, and the obtained initial temperature can be used as the initial polishing temperature.

[0083] The initial polishing temperature, the polishing sample temperature, the measured thickness of the polishing sample, and the water-polishing measured thickness as the metal film thickness can be used as a set of sample data to adjust the temperature correction information, such as adjusting equation (1), thereby obtaining the adjusted temperature correction information.

[0084] For example, the initial polishing temperature, the polishing sample temperature, the measured thickness of the polishing sample, and the water polishing measured thickness as the metal film thickness can be used as a set of sample data, and the above equations (2) and (4) can be fitted to the sample data to obtain the adjusted equation (1). Specifically, for the above equations (2) and (4), the initial polishing temperature can be substituted into T i (t), the polished sample temperature is substituted into T (ini-i) , substitute the measured thickness of the polished sample into THK (cal-i)(t), the thickness of the metal film measured by water polishing is substituted into THK real-i .

[0085] S360: adjusting the obtained thickness of the metal film according to the adjusted temperature correction information to obtain an adjusted thickness of the metal film.

[0086] According to the temperature correction information, a first function expression with the measured thickness as an independent variable and the thickness of the metal film as a function value can be obtained. According to the adjusted temperature correction information, an adjusted second function expression with the measured thickness as an independent variable and the thickness of the metal film as a function value can be obtained. By dividing the second function expression by the first function expression, a ratio of the thickness of the metal film calculated by the second function expression to the thickness of the metal film calculated by the second function expression can be obtained. The ratio is used as an adjustment coefficient. When the thickness of the obtained metal film is adjusted, the thickness of the obtained metal film is multiplied by the adjustment coefficient to obtain the adjusted thickness of the metal film.

[0087] Alternatively, the current temperature, initial temperature and measured thickness corresponding to the obtained thickness of the metal film may be obtained. The measured thickness may be re-corrected according to the current temperature, the initial temperature and the adjusted temperature correction information to obtain the adjusted thickness of the metal film. The process of re-correcting the measured thickness may refer to the above embodiment of correcting the measured thickness according to the temperature correction information, which will not be described in detail here.

[0088] In the embodiment of the present application, it can be determined whether there is a water polishing stage in the process of polishing the metal film; in the case of a water polishing stage, the water polishing measured thickness of the metal film is determined according to the measurement signal collected in the water polishing stage, and the temperature correction information is adjusted according to the water polishing measured thickness to obtain the adjusted temperature correction information. The adjusted temperature correction information can fit the polishing conditions of the wafer this time, so that the accuracy of determining the thickness of the metal film can be improved based on the adjusted temperature correction information. In addition, the thickness of the obtained metal film is adjusted according to the adjusted temperature correction information, and the adjusted thickness of the metal film with higher thickness accuracy than the obtained metal film can be obtained. In some optional embodiments, if there is a water polishing stage, in the non-water polishing stage after the water polishing stage, the measured thickness is corrected according to the current temperature and the temperature correction information, and the thickness of the metal film is obtained, including: correcting the measured thickness according to the current temperature and the adjusted temperature correction information to obtain the thickness of the metal film. The specific implementation of this embodiment can refer to the above embodiment of correcting the measured thickness according to the current temperature and the temperature correction information, which will not be repeated here.

[0089] Since the adjusted temperature correction information is adjusted according to the water-polishing measured thickness, the adjusted temperature correction information has a better fitting effect with the polishing conditions of this polishing. Therefore, in the non-water-polishing stage after the water-polishing stage, the embodiment of the present application corrects the measured thickness according to the current temperature and the adjusted temperature correction information, which can effectively improve the accuracy of the correction of the measured thickness and obtain a more accurate thickness of the metal film.

[0090] like Figure 8 As shown, according to a second aspect of an embodiment of the present application, a device 800 for measuring the thickness of a metal film on a wafer during a polishing process is provided, the device comprising:

[0091] The acquisition unit 810 is used to acquire the current temperature and the current measurement signal; wherein the current temperature is used to indicate the temperature of the metal film of the wafer at the current moment; the current measurement signal is collected by the eddy current sensor, and the current measurement signal is related to the thickness of the metal film;

[0092] A measured thickness determination unit 820, configured to determine the measured thickness of the metal film according to the current measurement signal;

[0093] The correction unit 830 is used to correct the measured thickness according to the current temperature and the temperature correction information to obtain the thickness of the metal film; the temperature correction information is used to indicate the relationship between the current temperature, the measured thickness and the thickness of the metal film.

[0094] The device for measuring the thickness of a metal film on a wafer during the polishing process of this embodiment is based on the same inventive concept as the method for measuring the thickness of a metal film on a wafer during the polishing process described above, and is used to implement the corresponding method for measuring the thickness of a metal film on a wafer during the polishing process in the aforementioned multiple method embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be described in detail here. In addition, the functional implementation of each unit in the device for measuring the thickness of a metal film on a wafer during the polishing process of this embodiment can refer to the description of the corresponding parts in the aforementioned method embodiments, which will not be described in detail here.

[0095] According to a third aspect of the embodiments of the present application, a chemical mechanical polishing device is provided, such as Figure 4 As shown, the chemical mechanical polishing equipment 10 may include: a polishing disc 11, a carrier head 12, an eddy current sensor 13, a polishing pad 14, a controller 15, a liquid supply device 16 and a temperature sensor 17; the carrier head 12 loads the wafer to be polished and abuts it against the polishing pad 14 above the polishing disc 11, and the liquid supply device 16 supplies polishing liquid between the polishing pad and the wafer; the eddy current sensor 13 is used to collect the current measurement signal, and the temperature sensor 17 is used to detect the current temperature; the controller 15 is used to perform the following steps:

[0096] The current temperature and the current measurement signal are obtained; wherein the current temperature is used to indicate the temperature of the metal film of the wafer at the current moment; the current measurement signal is collected by the eddy current sensor, and the current measurement signal is related to the thickness of the metal film.

[0097] The measured thickness of the metal film is determined based on the current measurement signal.

[0098] The measured thickness is corrected according to the current temperature and the temperature correction information to obtain the thickness of the metal film; the temperature correction information is used to indicate the relationship between the current temperature, the measured thickness and the thickness of the metal film.

[0099] In some optional embodiments, the measured thickness is corrected according to the current temperature and the temperature correction information to obtain the thickness of the metal film, including:

[0100] The temperature change difference of the metal film is determined according to the current temperature and the initial temperature, and the initial temperature is used to indicate the temperature of the metal film when the metal film is started to be polished.

[0101] The measured thickness is corrected according to the temperature variation difference and the temperature correction information to obtain the thickness of the metal film; wherein the temperature correction information is used to indicate the relationship between the temperature variation difference, the measured thickness and the thickness of the metal film.

[0102] In some optional embodiments, the steps performed by the controller further include:

[0103] The obtained thickness of the metal film is compared with the target thickness, and when the thickness of the metal film is less than or equal to the target thickness, the polishing operation on the metal film is terminated.

[0104] In some optional embodiments, the steps performed by the controller further include:

[0105] When the thickness of the obtained metal film is greater than the target thickness, the polishing operation performed on the metal film is controlled according to the target thickness.

[0106] In some optional embodiments, obtaining the current temperature and the current measurement signal includes:

[0107] The current temperature of the polishing pad and the current measurement signal are acquired, and the current temperature of the polishing pad is determined as the current temperature.

[0108] In some optional embodiments, the temperature correction information includes:

[0109] THK comp =(T(t)-T ini )*F(THK)+THK

[0110] Among them, THK compis used to indicate the thickness of the metal film, T(t) is used to indicate the current temperature, T ini Used to indicate the initial temperature, T(t)-T ini It is used to indicate the temperature change difference, THK is used to indicate the measured thickness, and F(THK) is used to indicate (THK comp -THK) and (T(t)-T ini ), and F(THK) is a function determined with THK as the independent variable.

[0111] In some optional embodiments, the steps performed by the controller further include:

[0112] Multiple wafers with different initial thicknesses of metal films are used as wafer samples. Without adding polishing liquid, each wafer sample is polished separately. During the polishing process, the temperature of the polishing pad and the sample measurement signal are obtained. The temperature of the polishing pad is used as the sample temperature of the metal film of the polished wafer sample, and the temperature of the polishing pad when the wafer sample starts to be polished is used as the initial temperature corresponding to the metal film. According to the sample measurement signal, the corresponding sample measurement thickness of the wafer sample is determined.

[0113] The initial temperature at which the metal film of each wafer sample is polished is recorded, as well as the sample measured thickness of each wafer sample at multiple sample temperatures.

[0114] According to the initial temperature, the metal film thickness of the wafer sample, multiple sample temperatures and the sample measured thickness at the multiple sample temperatures, the F(THK) sample values ​​corresponding to the multiple sample measured thicknesses are determined; wherein the metal film thickness of the wafer sample is equal to the initial thickness.

[0115] The sample measured thickness is used as an independent variable, and the sample value of F (THK) corresponding to the sample measured thickness is used as a function value to determine the functional relationship of F (THK) in the temperature correction information.

[0116] In some optional embodiments, the steps performed by the controller further include:

[0117] It is determined whether there is a water polishing stage during the polishing of the metal film, wherein the water polishing stage is a polishing stage in which the supply of polishing liquid to the wafer is stopped and pure water is supplied to the wafer.

[0118] If there is a water polishing stage, the water polishing measurement thickness of the metal film is determined according to the measurement signal collected during the water polishing stage, and the temperature correction information is adjusted according to the water polishing measurement thickness to obtain the adjusted temperature correction information.

[0119] The obtained thickness of the metal film is adjusted according to the adjusted temperature correction information to obtain the adjusted thickness of the metal film.

[0120] In some optional embodiments, if there is a water polishing stage, then in a non-water polishing stage after the water polishing stage, the measured thickness is corrected according to the current temperature and temperature correction information to obtain the thickness of the metal film, including: correcting the measured thickness according to the current temperature and adjusted temperature correction information to obtain the thickness of the metal film.

[0121] As a feasible implementation manner, the controller 15 may include a processor and a computer program. When the processor runs the computer program, the steps / methods in any of the aforementioned method embodiments can be implemented.

[0122] The chemical mechanical polishing equipment of this embodiment and the embodiment of the method for measuring the thickness of a metal film on a wafer during polishing are based on the same inventive concept, and are used to implement the method for measuring the thickness of a metal film on a wafer during polishing in the aforementioned multiple method embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be described in detail here. In addition, the functional implementation of each unit in the chemical mechanical polishing equipment of this embodiment can refer to the description of the corresponding parts in the aforementioned method embodiments, which will not be described in detail here.

[0123] According to a fourth aspect of the embodiments of the present application, a computer storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the method described in any of the above-mentioned multiple method embodiments is implemented. The computer storage medium includes, but is not limited to: a compact disc read-only memory (CD-ROM), a random access memory (RAM), a floppy disk, a hard disk, or a magneto-optical disk, etc.

[0124] It should be pointed out that, according to the needs of implementation, the various components / steps described in the embodiments of the present application can be split into more components / steps, or two or more components / steps or partial operations of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of the present application.

[0125] The above-mentioned method according to the embodiment of the present application can be implemented in hardware, firmware, or implemented as software or computer code that can be stored in a recording medium (such as a CD-ROM, RAM, floppy disk, hard disk or magneto-optical disk), or implemented as a computer code originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded through a network and to be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor or programmable or dedicated hardware (such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0126] Those of ordinary skill in the art will appreciate that the units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0127] The above implementation methods are only used to illustrate the embodiments of the present application, and are not limitations on the embodiments of the present application. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application. The scope of patent protection of the embodiments of the present application should be limited by the claims.

Claims

1. A method for measuring the thickness of a metal film on a wafer during a polishing process, characterized in that: include: Acquire a current temperature and a current measurement signal; wherein the current temperature is used to indicate the temperature of the metal film of the wafer at the current moment; the current measurement signal is collected by an eddy current sensor, and the current measurement signal is related to the thickness of the metal film; Determining a measured thickness of the metal film according to the current measurement signal; Correcting the measured thickness according to the current temperature and temperature correction information to obtain the thickness of the metal film; the temperature correction information is used to indicate the relationship between the current temperature, the measured thickness and the thickness of the metal film; The method further comprises: In the water polishing stage in the process of polishing the metal film, the temperature change of the metal film is detected to determine whether the temperature of the metal film is stable, and the measurement signal collected by the eddy current sensor is obtained when the temperature of the metal film of the wafer is in a stable state during the water polishing stage, and the water polishing measurement thickness of the metal film is determined as the thickness of the metal film according to the measurement signal; The initial temperature of the metal film at the beginning of the non-water polishing stage before the water polishing stage is obtained as the initial polishing temperature; the temperature of the metal film at the beginning of the water polishing stage is used as the polishing sample temperature; the measurement signal collected at the beginning of the water polishing stage is used as the polishing sample measurement signal, and the corresponding measurement thickness is determined according to the polishing sample measurement signal as the polishing sample measurement thickness; Taking the initial polishing temperature, the polishing sample temperature, the measured thickness of the polishing sample, and the thickness of the metal film as a set of sample data, adjusting the temperature correction information to obtain the adjusted temperature correction information; In a non-water polishing stage after the water polishing stage, the measured thickness is corrected according to the current temperature and the adjusted temperature correction information to obtain the thickness of the metal film.

2. The method according to claim 1, characterized in that The step of correcting the measured thickness according to the current temperature and the temperature correction information to obtain the thickness of the metal film includes: Determining a temperature change difference of the metal film according to the current temperature and an initial temperature, wherein the initial temperature is used to indicate the temperature of the metal film when polishing of the metal film begins; The measured thickness is corrected according to the temperature variation difference and the temperature correction information to obtain the thickness of the metal film; wherein the temperature correction information is used to indicate the relationship among the temperature variation difference, the measured thickness and the thickness of the metal film.

3. The method according to claim 1, characterized in that: The method further includes: comparing the obtained thickness of the metal film with a target thickness, and when the thickness of the metal film is less than or equal to the target thickness, terminating the polishing operation on the metal film.

4. The method according to claim 3, characterized in that The method further includes: when the obtained thickness of the metal film is greater than the target thickness, controlling a polishing operation performed on the metal film according to the target thickness.

5. The method according to claim 2, characterized in that: The temperature correction information includes: THK comp =(T(t)-T ini )*F(THK)+THK Among them, THK comp is used to indicate the thickness of the metal film, T(t) is used to indicate the current temperature, T ini Used to indicate the initial temperature, T(t)-T ini It is used to indicate the temperature change difference, THK is used to indicate the measured thickness, and F(THK) is used to indicate (THK comp -THK) and (T(t)-T ini ), and F(THK) is a function determined with THK as the independent variable.

6. The method according to claim 5, characterized in that The method further comprises: Using multiple wafers with different initial thicknesses of metal films as wafer samples, polishing each of the wafer samples separately without adding polishing liquid; obtaining the temperature of the polishing pad and the sample measurement signal during the polishing process; using the temperature of the polishing pad as the sample temperature of the metal film of the polished wafer sample, and using the temperature of the polishing pad when the wafer sample starts to be polished as the initial temperature corresponding to the metal film; determining the corresponding sample measurement thickness of the wafer sample according to the sample measurement signal; Recording the initial temperature for polishing the metal film of each wafer sample and the sample measured thickness of each wafer sample at a plurality of sample temperatures; Determine F(THK) sample values ​​corresponding to the plurality of sample measured thicknesses according to the initial temperature, the metal film thickness of the wafer sample, the plurality of sample temperatures, and the sample measured thicknesses at the plurality of sample temperatures; wherein the metal film thickness of the wafer sample is equal to the initial thickness; The measured thickness of the sample is used as an independent variable, and the sample value of F (THK) corresponding to the measured thickness of the sample is used as a function value to determine a functional relationship of F (THK) in the temperature correction information.

7. The method according to any one of claims 1 to 6, characterized in that The obtaining of the current temperature and the current measurement signal comprises: The current temperature of the polishing pad and the current measurement signal are acquired, and the current temperature of the polishing pad is determined as the current temperature.

8. A device for measuring the thickness of a metal film on a wafer during a polishing process, characterized in that: include: An acquisition unit, used to acquire a current temperature and a current measurement signal; wherein the current temperature is used to indicate the temperature of the metal film of the wafer at the current moment; the current measurement signal is collected by an eddy current sensor, and the current measurement signal is related to the thickness of the metal film; a measured thickness determination unit, configured to determine the measured thickness of the metal film according to the current measurement signal; a correction unit, configured to correct the measured thickness according to the current temperature and temperature correction information to obtain the thickness of the metal film; the temperature correction information is configured to indicate a relationship between the current temperature, the measured thickness, and the thickness of the metal film; The correction unit is also used for: In the water polishing stage in the process of polishing the metal film, the temperature change of the metal film is detected to determine whether the temperature of the metal film is stable, and the measurement signal collected by the eddy current sensor is obtained when the temperature of the metal film of the wafer is in a stable state during the water polishing stage, and the water polishing measurement thickness of the metal film is determined as the thickness of the metal film according to the measurement signal; The initial temperature of the metal film at the beginning of the non-water polishing stage before the water polishing stage is obtained as the initial polishing temperature; the temperature of the metal film at the beginning of the water polishing stage is used as the polishing sample temperature; the measurement signal collected at the beginning of the water polishing stage is used as the polishing sample measurement signal, and the corresponding measurement thickness is determined according to the polishing sample measurement signal as the polishing sample measurement thickness; The initial polishing temperature, the polishing sample temperature, the measured thickness of the polishing sample, and the thickness of the metal film are taken as a group of sample data, and the temperature correction information is adjusted to obtain the adjusted temperature correction information; in the non-water polishing stage after the water polishing stage, the measured thickness is corrected according to the current temperature and the adjusted temperature correction information to obtain the thickness of the metal film.

9. A chemical mechanical polishing device, characterized in that: include: It includes a polishing disc, a carrier head, a liquid supply device, an eddy current sensor, a controller and a temperature sensor; The carrier head loads the wafer to be polished and abuts it against the polishing pad above the polishing plate, and the liquid supply device supplies polishing liquid between the polishing pad and the wafer; the eddy current sensor is used to collect the current measurement signal; the temperature sensor is used to detect the current temperature, and the controller is used to perform the following steps: Acquire a current temperature and a current measurement signal; wherein the current temperature is used to indicate the temperature of the metal film of the wafer at the current moment; the current measurement signal is collected by an eddy current sensor, and the current measurement signal is related to the thickness of the metal film; Determining a measured thickness of the metal film according to the current measurement signal; Correcting the measured thickness according to the current temperature and temperature correction information to obtain the thickness of the metal film; the temperature correction information is used to indicate the relationship between the current temperature, the measured thickness and the thickness of the metal film; The controller is also used to: detect the temperature change of the metal film during the water polishing stage in the process of polishing the metal film to determine whether the temperature of the metal film is stable, obtain the measurement signal collected by the eddy current sensor when the temperature of the metal film of the wafer is in a stable state during the water polishing stage, and determine the water polishing measurement thickness of the metal film as the metal film thickness according to the measurement signal; The initial temperature of the metal film at the beginning of the non-water polishing stage before the water polishing stage is obtained as the initial polishing temperature; the temperature of the metal film at the beginning of the water polishing stage is used as the polishing sample temperature; the measurement signal collected at the beginning of the water polishing stage is used as the polishing sample measurement signal, and the corresponding measured thickness is determined according to the polishing sample measurement signal as the polishing sample measurement thickness; the polishing initial temperature, the polishing sample temperature, the polishing sample measurement thickness, and the metal film thickness are used as a group of sample data to adjust the temperature correction information to obtain the adjusted temperature correction information; in the non-water polishing stage after the water polishing stage, the measured thickness is corrected according to the current temperature and the adjusted temperature correction information to obtain the thickness of the metal film.

10. The chemical mechanical polishing equipment according to claim 9, characterized in that: Correcting the measured thickness according to the current temperature and the temperature correction information to obtain the thickness of the metal film includes: Determining a temperature change difference of the metal film according to the current temperature and an initial temperature, wherein the initial temperature is used to indicate the temperature of the metal film when polishing of the metal film begins; The measured thickness is corrected according to the temperature variation difference and the temperature correction information to obtain the thickness of the metal film; wherein the temperature correction information is used to indicate the relationship among the temperature variation difference, the measured thickness and the thickness of the metal film.

11. The chemical mechanical polishing equipment according to claim 9, characterized in that: The steps performed by the controller also include: The obtained thickness of the metal film is compared with the target thickness, and when the thickness of the metal film is less than or equal to the target thickness, the polishing operation on the metal film is terminated.

12. The chemical mechanical polishing equipment according to claim 11, characterized in that: The steps performed by the controller also include: When the obtained thickness of the metal film is greater than the target thickness, the polishing operation performed on the metal film is controlled according to the target thickness.

13. The chemical mechanical polishing equipment according to claim 10, characterized in that: The temperature correction information includes: THK comp =(T(t)-T ini )*F(THK)+THK Among them, THK comp is used to indicate the thickness of the metal film, T(t) is used to indicate the current temperature, T ini Used to indicate the initial temperature, T(t)-T ini It is used to indicate the temperature change difference, THK is used to indicate the measured thickness, and F(THK) is used to indicate (THK comp -THK) and (T(t)-T ini ), and F(THK) is a function determined with THK as the independent variable.

14. The chemical mechanical polishing equipment according to claim 13, characterized in that: The steps performed by the controller also include: Using multiple wafers with different initial thicknesses of metal films as wafer samples, polishing each of the wafer samples separately without adding polishing liquid; obtaining the temperature of the polishing pad and the sample measurement signal during the polishing process; using the temperature of the polishing pad as the sample temperature of the metal film of the polished wafer sample, and using the temperature of the polishing pad when the wafer sample starts to be polished as the initial temperature corresponding to the metal film; determining the corresponding sample measurement thickness of the wafer sample according to the sample measurement signal; Recording the initial temperature for polishing the metal film of each wafer sample and the sample measured thickness of each wafer sample at a plurality of sample temperatures; Determine F(THK) sample values ​​corresponding to the plurality of sample measured thicknesses according to the initial temperature, the metal film thickness of the wafer sample, the plurality of sample temperatures, and the sample measured thicknesses at the plurality of sample temperatures; wherein the metal film thickness of the wafer sample is equal to the initial thickness; The measured thickness of the sample is used as an independent variable, and the sample value of F (THK) corresponding to the measured thickness of the sample is used as a function value to determine a functional relationship of F (THK) in the temperature correction information.

15. The chemical mechanical polishing equipment according to claim 9, characterized in that: The obtaining of the current temperature and the current measurement signal comprises: The current temperature of the polishing pad and the current measurement signal are acquired, and the current temperature of the polishing pad is determined as the current temperature.

16. A computer storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method according to any one of claims 1 to 7.

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