Wafer Grinding Time Prediction Method, Device, Electronic Device and Computer Storage Medium

Abstract

The embodiment of the present application provides a method, device, electronic device and computer storage medium for predicting the wafer grinding time. The method includes: during the chemical mechanical polishing of the wafer, obtaining the first light intensity of the target light received by the light detection module, where the target light is the light formed by the interference of the first split light and the second split light of the single-wavelength light transmitted by the light emission module to the polished layer of the wafer after propagating through the wafer, the first split light is the light transmitted to the polished layer and reflected on the surface of the polished layer in the single-wavelength light, and the second split light is the light refracted into the polished layer, reflected on the surface of the non-polished layer of the wafer, and refracted to the side of the polished layer away from the non-polished layer in the single-wavelength light; determining the first light intensity change waveform according to the obtained first light intensity; predicting the end point of the wafer grinding time according to at least part of the first light intensity change waveform. This solution can improve the accuracy of the determined end point of the grinding time during chemical mechanical polishing.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of wafer grinding, and in particular, to a method, device, electronic device and computer storage medium for predicting wafer grinding time. Background Technique

[0002] Chemical Mechanical Polishing (CMP) is a technology used to grind wafers. It grinds the layer to be ground on the wafer surface by combining mechanical and chemical methods to achieve planarization of the wafer surface topography.

[0003] Currently, when determining the grinding end point during the CMP process, generally, detection methods such as optical, eddy current, or drive motor current can be used for grinding end point detection. Among them, the optical detection method is relatively commonly used and effective. The specific process of using the optical detection method to determine the grinding end point can be as follows: Before CMP, the theoretical spectral curve at the end of grinding needs to be calculated based on parameters such as the reflectivity of the layer to be ground and the non-layer to be ground. During the CMP process, spectral detection data of the layer to be ground on the wafer surface is obtained through a spectral detection device to obtain the current actual spectral curve based on the spectral detection data. Then, the difference value is calculated based on the current actual spectral curve and the theoretical spectral curve. When the difference value is small, the current time can be determined as the time end point of grinding, and CMP is stopped.

[0004] However, the spectral detection device has relatively strict environmental requirements. Therefore, the consistency of the spectral detection data obtained through the spectral detection device under the same conditions is poor, resulting in the inaccuracy of the above-mentioned actual spectral curve. Therefore, the grinding end point determined during the CMP process is relatively inaccurate. Summary of the Invention

[0005] In view of this, the embodiments of the present application provide a method, device, electronic device and computer storage medium for predicting wafer grinding time to at least partially solve the above problems.

[0006] According to the first aspect of the embodiments of the present application, a method for predicting the wafer grinding time is provided, including: during the chemical mechanical polishing of the wafer, obtaining the first light intensity of the target light received by the light detection module, where the target light is the light formed by the interference of the first spectral component and the second spectral component of the single-wavelength light propagating through the wafer after the single-wavelength light is emitted by the light emission module to the layer to be polished of the wafer, the first spectral component is the light that is emitted to the layer to be polished and reflected by the surface of the layer to be polished among the single-wavelength light, and the second spectral component is the light that is refracted into the layer to be polished, reflected by the surface of the non-layer to be polished of the wafer, and refracted to the side of the layer to be polished away from the non-layer to be polished among the single-wavelength light; determining a first light intensity change waveform according to the obtained first light intensity; predicting the end point of the wafer grinding time according to at least part of the first light intensity change waveform.

[0007] According to the second aspect of the embodiments of the present application, a chemical mechanical polishing apparatus is provided, including: a polishing pad, a carrier head, a light emission module, a light detection module, and a controller; a polishing pad is provided on one side of the polishing disk, and an optical window penetrating through the polishing pad in the thickness direction of the polishing pad is opened on the polishing pad, and a cavity communicating with the optical window is opened in the polishing disk; the carrier head is used to position the wafer so that the layer to be polished of the wafer abuts against the polishing pad and drive the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; the light emission module is disposed in the cavity and is used to emit a single-wavelength light to the optical window so that the single-wavelength light passes through the optical window and is emitted to the side of the polishing pad away from the polishing disk; the light detection module is disposed in the cavity and is used to receive the target light propagated through the wafer after the single-wavelength light passes through the optical window when the wafer is opposite to the optical window, where the target light is the light formed by the interference of the first spectral component and the second spectral component of the single-wavelength light propagating through the wafer, the first spectral component is the light that is emitted to the layer to be polished and reflected by the surface of the layer to be polished among the single-wavelength light, and the second spectral component is the light that is refracted into the layer to be polished, reflected by the surface of the non-layer to be polished of the wafer, and refracted to the side of the layer to be polished away from the non-layer to be polished among the single-wavelength light; the controller is used to perform the following processing: during the chemical mechanical polishing of the wafer, obtaining the first light intensity of the target light received by the light detection module; determining a first light intensity change waveform according to the obtained first light intensity; predicting the end point of the wafer grinding time according to at least part of the first light intensity change waveform.

[0008] According to the third aspect of the embodiments of the present application, a computer storage medium is provided, on which a computer program is stored, and the program is executed by a processor to implement the method in the first aspect.

[0009] According to a fourth aspect of the embodiments of the present application, there is provided a computer program product including computer instructions that direct a computing device to execute the method of the first aspect described above.

[0010] According to the polishing time prediction solution provided by the embodiments of the present application, during the chemical mechanical polishing of a wafer, the first light intensity of the target light received by the optical detection module can be obtained, and based on the obtained first light intensity, a first light intensity change waveform can be determined. Then, based on at least a part of the first light intensity change waveform, the polishing time end point of the wafer can be predicted. Thus, in the present application, the end point of the polishing time is determined by the light intensity of the target light received by the optical detection module after the single-wavelength light is emitted by the light emission module. Compared with the solution of determining the polishing end point by the spectral detection data obtained by a spectral detection device, the requirements for the environment for determining the light intensity of the target light formed by the propagation of the single-wavelength light are relatively low, so that the detected first light intensity is relatively accurate. Furthermore, the first light intensity change waveform determined based on the first light intensity can more accurately reflect the thickness change of the polished layer of the wafer. Therefore, the accuracy of the determined polishing time end point during the chemical mechanical polishing process can be improved. Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the embodiments of the present application, and those of ordinary skill in the art can also obtain other drawings based on these drawings.

[0012] Figure 1 is a schematic diagram of a chemical mechanical polishing device according to an embodiment of the present application;

[0013] Figure 2 is a cross-sectional view of a chemical mechanical polishing device according to an embodiment of the present application;

[0014] Figure 3 is a schematic diagram of the propagation of single-wavelength light according to an embodiment of the present application;

[0015] Figure 4 is a flowchart of a wafer polishing time prediction method according to an embodiment of the present application;

[0016] Figure 5 is a schematic diagram of a first light intensity change waveform according to an embodiment of the present application;

[0017] Figure 6 is a schematic diagram of an electronic device according to an embodiment of the present application. Detailed Embodiments

[0018] An embodiment of the present application provides a method for predicting the wafer grinding time, which is used to determine the grinding end point during the chemical mechanical polishing of a wafer by a chemical mechanical polishing apparatus.

[0019] The chemical mechanical polishing apparatus includes a controller for executing the method for predicting the wafer grinding time. In a specific embodiment, as Figure 1 and Figure 2 shown, the chemical mechanical polishing apparatus includes a polishing platen 1, a carrier head 2, a light emitting module 3, a plane mirror 4, a light detection module 5 and a controller; a polishing pad 11 is provided on one side of the polishing platen 1, and an optical window 111 penetrating through the polishing pad 11 in the thickness direction of the polishing pad 11 is formed on the polishing pad 11. The shape of the polishing pad 11 is a circular pad shape. The polishing platen 1 is used to drive the polishing pad 11 to rotate around the axis of the polishing pad 11 during the chemical mechanical polishing process, and a cavity 12 communicating with the optical window 111 is formed in the polishing platen 1; the carrier head 2 is used to position the wafer (the installation position of the wafer w in the carrier head 2 can be as Figure 2 shown), so that the layer to be polished of the wafer abuts against the polishing pad 11, and drives the wafer to rotate around the axis of the wafer and reciprocate along the radial direction of the polishing pad 11 during the chemical mechanical polishing process, so that the wafer moves relative to the polishing pad 11 to realize chemical mechanical polishing of the wafer.

[0020] The light emitting module 3 is arranged in the cavity 12 and is used to emit single-wavelength light, such as single-wavelength red light, etc. The plane mirror 4 is arranged in the cavity 12 and is used to direct the single-wavelength light emitted by the target light emitting module 3 to the optical window 111, so that the light emitting module 3 emits single-wavelength light to the optical window 111, and then the single-wavelength light passes through the optical window 111 and is emitted to the space on the side of the polishing pad 11 away from the polishing platen 1. The light emitting module 3 can be, for example, a line laser, etc.; the light detection module 5 is arranged in the cavity 12 and is used to receive the target light that passes through the optical window 111 and is propagated by the wafer when the wafer is opposite to the optical window 111 (that is, when the wafer and the polishing pad 11 move relative to each other until at least a part of the layer to be polished of the wafer covers the optical window 111). Among them, the target light is the light formed by the interference of the first split light and the second split light of the single-wavelength light after being propagated by the wafer. The first split light is the light that is emitted to the layer to be polished and reflected by the surface of the layer to be polished in the single-wavelength light, and the second split light is the light that is refracted into the layer to be polished, reflected by the surface of the non-layer to be polished of the wafer, and refracted to the side of the layer to be polished away from the non-layer to be polished.

[0021] For example, as Figure 3As shown, p1 is the layer to be polished on the wafer, and p2 is the non-layer to be polished on the wafer. Based on this, m is the single-wavelength light reflected by the plane mirror 4, n is the first spectral component reflected by the surface of the layer to be polished on the wafer, x is the second spectral component refracted into the layer to be polished, y is the second spectral component reflected by the surface of the non-layer to be polished on the wafer, and z is the second spectral component refracted to the side of the layer to be polished away from the non-layer to be polished; the controller is electrically connected to the light detection module 5 and is used to execute the wafer polishing time prediction method. It can also be electrically connected to the light emission module 3 and is used to control the emission and stop emission of the single-wavelength light, etc. The specific functions of the controller in the embodiments of the present application are not limited.

[0022] Based on the above chemical mechanical polishing device, the wafer polishing time prediction method will be described in detail through multiple embodiments below.

[0023] Figure 4 It is a flowchart of the wafer polishing time prediction method according to an embodiment of the present application. As Figure 4 shown, the wafer polishing time prediction method includes the following steps:

[0024] Step 401: During the chemical mechanical polishing of the wafer, obtain the first light intensity of the target light received by the light detection module.

[0025] Theoretically, the light intensity I of the target light received by the light detection module satisfies the following formula:

[0026] I = I A + I B + 2 * (I A * I B )^0.5 * cosφ (Formula 1), where I A is the light intensity of the first spectral component after passing through the wafer, I B is the light intensity of the second spectral component after passing through the wafer, φ is the phase difference between the first spectral component and the second spectral component, φ = (2π / λ0) * 2 * n * d * cosα (Formula 2), λ0 is the wavelength of the single-wavelength light in vacuum, 2 * n * d * cosα is the optical path difference between the first spectral component and the second spectral component, n is the refractive index of the layer to be polished on the wafer, d is the thickness of the layer to be polished on the wafer (such as Figure 3 d in Figure 3 ), and α is the refraction angle of the single-wavelength light refracted into the layer to be polished in the layer to be polished (such as

[0027] α in Figure 2(as shown in the figure), based on this, during the chemical mechanical polishing of the wafer by the chemical mechanical polishing device, when the wafer and the polishing pad move relative to each other until at least part of the wafer's abrasion layer covers above the optical window, the light detection module can receive the target light reflected by the wafer and send the analog data of the received target light to the data acquisition module. The data acquisition module can perform analog-to-digital conversion on the analog data of the target light to obtain the first light intensity of the target light, realizing the solution of obtaining the first light intensity of the target light received by the light detection module.

[0028] It should be noted that at least one first light intensity can be obtained each time the wafer and the polishing pad move relative to each other until at least part of the wafer's abrasion layer covers above the optical window, or at least one first light intensity can be obtained separately only when the wafer and the polishing pad move relative to each other in some times until at least part of the wafer's abrasion layer covers above the optical window. The embodiments of the present application do not limit this.

[0029] Step 402: Determine the first light intensity change waveform according to the obtained first light intensity.

[0030] Among them, the first light intensity change waveform can be a continuous waveform image with time as the abscissa variable and the first light intensity as the ordinate variable.

[0031] In a specific embodiment, after the chemical mechanical polishing device performs chemical mechanical polishing on the wafer for a certain period of time (the duration can be determined according to actual needs, and the embodiments of the present application do not limit this), the controller can obtain multiple first light intensities and the time when the target light corresponding to each obtained first light intensity is received by the light detection module. At this time, according to the multiple first light intensities and the time when the target light corresponding to each first light intensity is received by the light detection module, a continuous waveform image with time as the abscissa variable and the first light intensity as the ordinate variable can be fitted, which is the first light intensity change waveform.

[0032] Based on the above formula of light intensity I, during the chemical mechanical polishing of the wafer by the chemical mechanical polishing device, since the light intensity of the single-wavelength light emitted by the light emission module is relatively constant and the material of the abrasion layer is fixed, so I in the above formula 1 A and I BAlmost unchanged, π, λ0, n, and cosα in the above formula 2 are all constants. That is, the only variable in the above formula 1 is cosφ. Specifically, because there is a unique variable d in formula 2. Since the grinding speed of the wafer during chemical mechanical polishing is basically constant, the reduction rate of d in formula 2 during chemical mechanical polishing is relatively constant, so that φ gradually decreases at a basically uniform speed during chemical mechanical polishing. Based on this, cosφ in formula 1 changes regularly with the wafer thickness during chemical mechanical polishing. That is, if the waveform of cosφ changing with the wafer thickness during chemical mechanical polishing is fitted, the wafer thickness change amounts corresponding to each half cycle (a half cycle is the part between adjacent wave peaks and wave valleys in the corresponding waveform, that is, the part from the wave peak to the adjacent wave valley and the part from the wave valley to the adjacent wave peak in this waveform are both one half cycle) in this waveform are almost the same. Furthermore, the wafer thickness change amounts corresponding to each half cycle in the corresponding first light intensity change waveform of I during chemical mechanical polishing are almost the same.

[0033] Step 403: Predict the grinding time end point of the wafer according to at least part of the first light intensity change waveform.

[0034] In a specific embodiment, considering that the wafer thickness change amounts corresponding to each half cycle in the first light intensity change waveform are also almost the same, the law of the thickness of the layer to be ground on the wafer changing with the first light intensity change waveform during chemical mechanical polishing of the wafer can be determined according to the first light intensity change waveform. Furthermore, during wafer processing, the controller may include a data processing module (such as Figure 2 shown) electrically connected to the data acquisition module. Based on this, when the data acquisition module obtains the first light intensity change waveform, it can send the first light intensity change waveform to the data processing module. The data processing module then selects at least part of the continuous first light intensity change waveform from the first light intensity change waveform to determine the corresponding acquisition time, and predicts the grinding time end point of the wafer in combination with this law.

[0035] In the embodiments of the present application, during the chemical mechanical polishing of a wafer, the first light intensity of the target light received by the optical detection module can be obtained, and based on the obtained first light intensity, the first light intensity change waveform can be determined. Then, based on at least part of the first light intensity change waveform, the polishing time end point of the wafer can be predicted. Thus, in the present application, after the light emission module emits a single-wavelength light, the polishing time end point is determined by the light intensity of the target light received by the optical detection module. Compared with the solution of determining the polishing end point based on the spectral detection data obtained by a spectral detection device, the requirements for the environment for determining the light intensity of the target light formed by the propagation of the single-wavelength light are relatively low, and the detected first light intensity is relatively accurate. Furthermore, the first light intensity change waveform determined based on the first light intensity can more accurately reflect the thickness change of the layer to be polished of the wafer. Therefore, the accuracy of the determined polishing time end point during the chemical mechanical polishing process can be improved.

[0036] In addition, compared with determining the polishing time end point by eddy current detection during the chemical mechanical polishing process, the wafer polishing time prediction method in the present application can be applied to any dielectric layer material whose layer to be polished can reflect and refract light, and the application range is wider.

[0037] The above step 403 can be implemented in at least the following two ways:

[0038] In a possible implementation, the above step 403 includes the following specific processing: determining the time difference between the start time and the end time of at least part of the first light intensity change waveform; calculating the thickness difference of the layer to be polished of the wafer at the start time and the end time of at least part of the first light intensity change waveform based on at least part of the first light intensity change waveform; determining the polishing rate according to the thickness difference and the time difference; and determining the polishing time end point of the chemical mechanical polishing of the wafer according to the polishing rate and the target polishing thickness of the chemical mechanical polishing of the wafer.

[0039] For example, as shown in the first light intensity change waveform Figure 5 where at least part of the first light intensity change waveform is Figure 5 the waveform H in it. Based on this, the time difference between the start time and the end time of H can be obtained, and the thickness difference of the layer to be polished of the wafer at the start time and the end time of H can be calculated. Then, the polishing rate v can be determined according to the time difference and the thickness difference. Based on this, before the chemical mechanical polishing of the wafer, the target polishing thickness S of the wafer (i.e., the polishing amount of the wafer) can be determined. Furthermore, the polishing time end point of the chemical mechanical polishing of the wafer can be determined as the time point after a duration of time time after the start of polishing, where time = S / v.

[0040] Therefore, when determining the end point of the polishing time for the wafer in chemical mechanical polishing, it can be directly calculated according to the polishing rate and the target polishing thickness. The processing logic is simple and the computing resources are saved.

[0041] Optionally, the formula for determining the polishing rate according to the thickness difference and the time difference is as follows:

[0042] RR = ΔD / Δt, where RR is the polishing rate, ΔD is the thickness difference of the ground layer of the wafer at the start time and the end time of at least part of the first light intensity change waveform, and Δt is the time difference.

[0043] Optionally, the formula for calculating the thickness difference of the ground layer of the wafer at the start time and the end time of at least part of the first light intensity change waveform according to at least part of the first light intensity change waveform is as follows:

[0044] ΔD = N*λ0 / (2*n*cosα), where ΔD is the thickness difference of the ground layer of the wafer at the start time and the end time of at least part of the first light intensity change waveform, N is the number of fluctuation periods in at least part of the first light intensity change waveform, λ0 is the wavelength of the single-wavelength light in vacuum, n is the refractive index of the ground layer of the wafer, and α is the refraction angle of the single-wavelength light in the ground layer.

[0045] Therefore, compared with measuring the thickness difference of the ground layer of the wafer at the start time and the end time of at least part of the first light intensity change waveform, in this application, the thickness difference can be obtained by calculation, which is more convenient and improves the efficiency of determining the end point of the polishing time.

[0046] In another possible implementation manner, step 403 includes the following specific processing: predetermine the unit thickness, where the unit thickness is used to indicate the thickness change amount corresponding to each half cycle in the first light intensity change waveform, and the half cycle can be the part between adjacent wave peaks and wave valleys in the corresponding waveform; according to the target polishing thickness of the wafer in chemical mechanical polishing and the unit thickness, predict the number of half cycles of the first light intensity change waveform corresponding to reaching the end point of the polishing time from the start time, so as to determine the end point of the polishing time.

[0047] In a specific embodiment, after determining the unit thickness, during the chemical mechanical polishing of the wafer and obtaining the first light intensity, the number of half cycles num = S / Δd in the first light intensity change waveform when reaching the target polishing thickness can be calculated and determined as the end point of the chemical mechanical polishing of the wafer, where Δd is the unit thickness and S is the target polishing thickness. It should be noted that the number of half cycles in this application can be an integer or a decimal, that is, a specific point within the half cycle can be located, ensuring the accuracy of the determined end point of the polishing time.

[0048] Thus, when determining the end point of the polishing time for the wafer during chemical mechanical polishing, it is achieved by counting half - cycles during the chemical mechanical polishing process of the wafer. Thus, the thickness of the wafer that has been polished currently can be obtained, and the polished situation of the wafer can be monitored more accurately.

[0049] Optionally, the number of half - cycles in the first light intensity change waveform can be counted from the L - th peak or trough in the first light intensity change waveform, so as to perform half - cycle counting processing on a more accurate part of the first light intensity change waveform, improving the accuracy of the determined polishing end point. L can be set according to actual needs and can be directly subtracted when calculating the number of half - cycles. The embodiments of the present application do not limit this.

[0050] Take Figure 5 as an example. The more accurate part of the first light intensity change waveform can start from the starting point of H. And if the determined number of half - cycles num = 4.4, then start counting half - cycles from the starting point of H, and determine that after 4.4 half - cycles, it reaches the end point of H, that is, the polishing end point.

[0051] Optionally, the above unit thickness can be obtained through any one of the following two possible implementation manners.

[0052] In one possible implementation manner, the input unit thickness is obtained.

[0053] For example, the staff can calculate the unit thickness according to the actually measured wafer parameters. Or, the staff can perform chemical mechanical polishing on the wafer on the experimental bench, and obtain the light intensity change waveform of the target light received by the light detection module in the experimental bench, and then use the wafer thickness change amount corresponding to each half - cycle in the light intensity change waveform as the above unit thickness. Then, the staff can input the unit thickness into the controller, or pre - set it in the application program of the controller, so that the controller obtains the input unit thickness. Among them, the experimental bench can be simply built from a simulated chemical mechanical polishing device or a real and complete chemical mechanical polishing device. The embodiments of the present application do not limit this.

[0054] Similarly, parameters such as λ0, n, α, etc. can also be input, and the program can calculate the unit thickness Δd by itself. The calculation formula can be: Δd = λ0 / (4 * n * cosα), where λ0 is the wavelength of the single - wavelength light in vacuum, n is the refractive index of the layer to be polished of the wafer, and α is the refraction angle of the single - wavelength light in the layer to be polished.

[0055] In another possible implementation, during the chemical mechanical polishing of the wafer, and before obtaining the first light intensity of the target light received by the light detection module, obtain the second light intensity of the target light received by the light detection module; determine the second light intensity change waveform according to the obtained second light intensity; measure the thickness difference of the polished layer of the wafer corresponding to the start time and the end time of at least part of the second light intensity change waveform; determine the average thickness change amount corresponding to each half cycle in at least part of the second light intensity change waveform as the unit thickness according to the thickness difference and the number of half cycles in at least part of the second light intensity change waveform.

[0056] Among them, the specific method for obtaining the second light intensity is the same as the specific method for obtaining the first light intensity described above, and the specific method for determining the second light intensity change waveform is the same as the specific method for determining the first light intensity change waveform described above. The embodiments of the present application will not be elaborated herein.

[0057] For example, approximately 2.2 fluctuation cycles, that is, 4.4 half cycles, are included in at least part of the second light intensity change waveform described above. Based on this, according to the thickness difference ΔD2 of the polished layer of the wafer at the start time and the end time of at least part of the second light intensity change waveform described above, determine the average thickness change amount Δd = ΔD2 / 4.4 corresponding to each half cycle in at least part of the second light intensity change waveform, and use this Δd as the unit thickness.

[0058] Thus, compared with measuring the thickness difference of the polished layer of the wafer at the start time and the end time of at least part of the second light intensity change waveform described above, in the present application, the thickness difference can be obtained by calculation, which is more convenient and improves the efficiency of determining the polishing end point.

[0059] Optionally, the wafers corresponding to the first light intensity change waveform and the second light intensity change waveform described above can be the same wafer, or wafers with the same wafer model, size, structure, etc. (such as wafers of the same batch and the same model). The embodiments of the present application do not limit this.

[0060] Corresponding to the above method embodiments, the embodiments of the present application also provide a chemical mechanical polishing device, as Figure 1 and Figure 2 shown, the chemical mechanical polishing device includes: a polishing platen 1, a carrier head 2, a light emitting module 3, a light detection module 5, and a controller;

[0061] A polishing pad 11 is provided on one side of the polishing platen 1. An optical window 111 penetrating the polishing pad 11 in the thickness direction of the polishing pad 11 is opened on the polishing pad 11, and a cavity 12 communicating with the optical window 111 is opened in the polishing platen 1;

[0062] A carrier head 2 for limiting the wafer so that the layer to be polished of the wafer abuts against the polishing pad 11 and driving the wafer to move relative to the polishing pad 11 to perform chemical mechanical polishing on the wafer;

[0063] An optical emission module 3 disposed in the cavity 12 for emitting a single-wavelength light to the optical window 111 so that the single-wavelength light passes through the optical window 111 and is emitted to the side of the polishing pad 11 away from the polishing platen 1;

[0064] An optical detection module 5 disposed in the cavity 12 for receiving, when the wafer is opposite to the optical window 111, the target light that is the single-wavelength light passing through the optical window 111 and propagated through the wafer. The target light is the light formed by the interference of the first split light and the second split light of the single-wavelength light after being propagated through the wafer. The first split light is the light that is emitted to the layer to be polished of the single-wavelength light and reflected on the surface of the layer to be polished, and the second split light is the light that is refracted into the layer to be polished, reflected on the surface of the non-layer to be polished of the wafer, and refracted to the side of the layer to be polished away from the non-layer to be polished;

[0065] A controller for performing the following processes:

[0066] During the chemical mechanical polishing of the wafer, obtaining the first light intensity of the target light received by the optical detection module 5;

[0067] Determining a first light intensity change waveform according to the obtained first light intensity;

[0068] Predicting the end point of the polishing time of the wafer according to at least part of the first light intensity change waveform.

[0069] In a possible implementation manner, the chemical mechanical polishing apparatus further includes a plane mirror 4; the plane mirror 4 is disposed in the cavity 12 for reflecting the single-wavelength light emitted by the optical emission module 3 to the optical window 111 so that the optical emission module 3 emits the single-wavelength light to the optical window 111.

[0070] In a possible implementation manner, the plane mirror 4 is rotatably connected to the polishing platen 1 about an axis parallel to the mirror surface of the plane mirror 4. Thus, by rotating the plane mirror 4 relative to the polishing platen 1, the angle at which the single-wavelength light is emitted to the optical window 111 can be adjusted, improving the adjustability and fault tolerance of the chemical mechanical polishing apparatus.

[0071] In a possible implementation manner, the controller's predicting the end point of the polishing time of the wafer according to at least part of the first light intensity change waveform includes:

[0072] Determining the time difference between the start time and the end time of the above at least part of the first light intensity change waveform;

[0073] Based on at least part of the above-mentioned first light intensity change waveform, calculate the thickness difference of the layer to be polished of the wafer at the start time and the end time of at least part of the above-mentioned first light intensity change waveform;

[0074] Determine the polishing rate based on the thickness difference and the time difference;

[0075] Based on the polishing rate and the target polishing thickness for chemical mechanical polishing of the wafer, determine the polishing time end point for chemical mechanical polishing of the wafer.

[0076] In a possible implementation, the formula for the controller to execute to calculate the thickness difference of the layer to be polished of the wafer at the start time and the end time of at least part of the above-mentioned first light intensity change waveform based on at least part of the above-mentioned first light intensity change waveform is as follows:

[0077] ΔD = N * λ0 / (2 * n * cosα), where ΔD is the thickness difference of the layer to be polished of the wafer at the start time and the end time of at least part of the above-mentioned first light intensity change waveform, N is the number of fluctuation cycles in at least part of the above-mentioned first light intensity change waveform, λ0 is the wavelength of the single-wavelength light in vacuum, n is the refractive index of the layer to be polished of the wafer, and α is the refraction angle of the single-wavelength light refracted into the layer to be polished in the layer to be polished.

[0078] In a possible implementation, the controller executes to predict the polishing time end point of the wafer based on at least part of the first light intensity change waveform, including:

[0079] Predetermine the unit thickness in advance, where the unit thickness is used to indicate the thickness change amount corresponding to each half cycle in the first light intensity change waveform, and the half cycle is the part between adjacent wave peaks and wave valleys in the corresponding waveform;

[0080] Based on the target polishing thickness for chemical mechanical polishing of the wafer and the unit thickness, predict the number of half cycles of the first light intensity change waveform corresponding to reaching the polishing time end point from the start time to determine the polishing time end point.

[0081] In a possible implementation, the unit thickness is obtained by one of the following methods:

[0082] Obtain the input unit thickness;

[0083] Or,

[0084] During the chemical mechanical polishing process of the wafer, and before obtaining the first light intensity of the target light received by the light detection module, obtain the second light intensity of the target light received by the light detection module; determine the second light intensity change waveform according to the obtained second light intensity; measure the thickness difference of the polished layer of the wafer corresponding to the start time and the end time of at least part of the second light intensity change waveform; determine the average thickness change amount corresponding to each half cycle in the at least part of the second light intensity change waveform as the unit thickness according to the thickness difference and the number of half cycles in the at least part of the second light intensity change waveform.

[0085] In a possible implementation manner, the formula for calculating the thickness difference of the polished layer of the wafer at the start time and the end time of at least part of the second light intensity change waveform executed by the controller is as follows:

[0086] The specific structure of the chemical mechanical polishing equipment has been described in the method embodiments, and will not be repeated in the embodiments of the present application.

[0087] It should be noted that the chemical mechanical polishing device of this embodiment is used to implement the corresponding wafer polishing time prediction method in the foregoing method embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0088] Figure 6 It is a schematic block diagram of an electronic device provided by an embodiment of the present application. The specific implementation of the electronic device is not limited in the specific embodiments of the present application. As Figure 6 shown, the electronic device may include: a processor 602, a communication interface 604, a memory 606, and a communication bus 608. Among them:

[0089] The processor 602, the communication interface 604, and the memory 606 communicate with each other through the communication bus 608.

[0090] The communication interface 604 is used to communicate with other electronic devices or servers.

[0091] The processor 602 is used to execute the program 610, and specifically may execute the relevant steps in any of the foregoing wafer polishing time prediction method embodiments.

[0092] Specifically, the program 610 may include program code, and the program code includes computer operation instructions.

[0093] The processor 602 may be a CPU, or a specific application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. One or more processors included in the intelligent device may be of the same type of processor, such as one or more CPUs; or may be of different types of processors, such as one or more CPUs and one or more ASICs.

[0094] RISC-V is an open-source instruction set architecture based on the principle of reduced instruction set computing (RISC). It can be applied to various aspects such as microcontrollers and FPGA chips, and can be specifically applied in the fields of Internet of Things security, industrial control, mobile phones, personal computers, etc. Moreover, due to the consideration of small size, high speed, and low power consumption during its design, it is particularly suitable for modern computing devices such as warehouse-scale cloud computers, high-end mobile phones, and tiny embedded systems. With the rise of artificial intelligence Internet of Things (AIoT), the RISC-V instruction set architecture has received increasing attention and support, and is expected to become the next-generation CPU architecture widely used.

[0095] The computer operation instructions in the embodiments of the present application may be computer operation instructions based on the RISC-V instruction set architecture. Correspondingly, the processor 602 may be designed based on the RISC-V instruction set. Specifically, the chip of the processor in the electronic device provided in the embodiments of the present application may be a chip designed using the RISC-V instruction set. The chip may execute executable code based on the configured instructions, thereby implementing the wafer grinding time prediction method in the above embodiments.

[0096] The memory 606 is used to store the program 610. The memory 606 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk memory.

[0097] The program 610 may specifically be used to cause the processor 602 to execute the wafer grinding time prediction method in any of the foregoing embodiments.

[0098] For the specific implementation of each step in the program 610, reference may be made to the corresponding steps and descriptions in the corresponding units in any of the foregoing embodiments of the wafer grinding time prediction method, which will not be elaborated herein. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described devices and modules may refer to the corresponding process descriptions in the foregoing method embodiments, which will not be repeated herein.

[0099] The present application also provides a computer-readable storage medium storing instructions for causing a machine to execute the wafer grinding time prediction method as described herein. Specifically, a system or device equipped with the storage medium may be provided, on which software program code for implementing the functions of any one of the above embodiments is stored, and the computer (or CPU or MPU) of the system or device is caused to read and execute the program code stored in the storage medium.

[0100] In this case, the program code read from the storage medium itself can implement the functions of any one of the above embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present application.

[0101] Examples of the storage medium for providing the program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, the program code may be downloaded from a server computer via a communication network.

[0102] The embodiments of the present application also provide a computer program product including computer instructions that direct a computing device to perform any corresponding operation in the above-described multiple method embodiments.

[0103] It should be noted that the information related to users (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data for training a model, data for analysis, stored data, displayed data, etc.) involved in the embodiments of the present application are all information and data that have been authorized by the users or fully authorized by all parties, and the collection, use, and processing of the relevant data need to comply with the relevant laws, regulations, and standards of the relevant countries and regions, and corresponding operation entrances are provided for users to choose to authorize or reject.

[0104] It should be pointed out that, according to the needs of implementation, the various components / steps described in the embodiments of the present application may be split into more components / steps, or two or more components / steps or partial operations of components / steps may be combined into new components / steps to achieve the purpose of the embodiments of the present application.

[0105] The method according to the embodiments of the present application can be implemented in hardware, firmware, or be 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 be implemented as computer code originally stored in a remote recording medium or a non-transitory machine-readable medium and 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 ASIC or FPGA). It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component (such as RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the method shown herein.

[0106] It should be noted that the information related to users (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data for training the model, data for analysis, stored data, displayed data, etc.) involved in the embodiments of the present application are all information and data that have been authorized by the users or fully authorized by all parties, and the collection, use, and processing of the relevant data need to comply with the relevant laws, regulations, and standards of the relevant countries and regions, and corresponding operation entrances are provided for users to select to authorize or refuse.

[0107] Those of ordinary skill in the art can realize that the units and method steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for a specific application, but such implementation should not be considered to exceed the scope of the embodiments of the present application.

[0108] The above embodiments are only used to illustrate the embodiments of the present application, rather than to limit the embodiments of the present application. Those of ordinary skill in the relevant technical fields 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, and the patent protection scope of the embodiments of the present application should be defined by the claims.

Claims

1. A method for predicting the wafer grinding time, characterized in that, Including: During the chemical mechanical polishing (CMP) of a wafer, obtain a first light intensity of target light received by a light detection module, where the target light is light formed by interference of a first split light and a second split light of a single-wavelength light propagated through the wafer when the light emission module emits the single-wavelength light to a polished layer of the wafer. The first split light is the light in the single-wavelength light that is emitted to the polished layer and reflected by the surface of the polished layer. The second split light is the light in the single-wavelength light that is refracted into the polished layer, reflected by the surface of a non-polished layer of the wafer, and refracted to the side of the polished layer away from the non-polished layer. Determine a first light intensity change waveform based on the obtained first light intensity. Pre-determine a unit thickness, where the unit thickness is used to indicate a thickness change amount corresponding to a half cycle in the first light intensity change waveform. Based on a target polishing thickness for CMP of the wafer and the unit thickness, predict the number of half cycles of the first light intensity change waveform corresponding to reaching the end point of the polishing time from a starting time to determine the end point of the polishing time, where the number of half cycles is a decimal. The unit thickness is obtained as follows: During the CMP of the wafer and before obtaining the first light intensity of the target light received by the light detection module, obtain a second light intensity of the target light received by the light detection module; determine a second light intensity change waveform based on the obtained second light intensity; measure a thickness difference of the polished layer of the wafer corresponding to the starting time and the ending time of at least part of the second light intensity change waveform; determine an average thickness change amount corresponding to a half cycle in at least part of the second light intensity change waveform as the unit thickness based on the thickness difference and the number of half cycles in at least part of the second light intensity change waveform.

2. The method according to claim 1, wherein The predicting the end point of the polishing time of the wafer based on at least part of the first light intensity change waveform includes: Determine a time difference between the starting time and the ending time of at least part of the first light intensity change waveform. Based on at least part of the first light intensity change waveform, calculate a thickness difference of the polished layer of the wafer at the starting time and the ending time of at least part of the first light intensity change waveform. Determine a polishing rate based on the thickness difference and the time difference. Based on the polishing rate and the target polishing thickness for CMP of the wafer, determine the end point of the polishing time for CMP of the wafer.

3. The method according to claim 2, characterized in that, The formula for calculating the thickness difference of the polished layer of the wafer at the starting time and the ending time of at least part of the first light intensity change waveform based on at least part of the first light intensity change waveform is as follows: ΔD = N * λ0 / (2 * n * cosα), where ΔD is the thickness difference of the polished layer of the wafer at the starting time and the ending time of at least part of the first light intensity change waveform, N is the number of fluctuation cycles in at least part of the first light intensity change waveform, λ0 is the wavelength of the single-wavelength light in vacuum, n is the refractive index of the polished layer of the wafer, and α is the refraction angle of the single-wavelength light in the polished layer.

4. A chemical mechanical polishing device, characterized in that, Including: A polishing pad, a carrier head, a light emission module, a light detection module, and a controller. A polishing pad is provided on one side of the polishing platen. An optical window is formed in the polishing pad and penetrates through the polishing pad in the thickness direction of the polishing pad. A cavity communicating with the optical window is formed in the polishing platen; The carrier head is used to limit the wafer so that the layer to be polished of the wafer abuts against the polishing pad and drives the wafer to move relative to the polishing pad to perform chemical mechanical polishing on the wafer; The light emitting module is disposed in the cavity and is used to emit single-wavelength light to the optical window so that the single-wavelength light passes through the optical window and is emitted to the side of the polishing pad away from the polishing platen; The light detection module is disposed in the cavity and is used to receive the target light that the single-wavelength light passes through the optical window and then propagates through the wafer when the wafer is opposite to the optical window. The target light is the light formed by the interference of the first spectral component and the second spectral component of the single-wavelength light after propagating through the wafer. The first spectral component is the light of the single-wavelength light that is emitted to the layer to be polished and reflected by the surface of the layer to be polished. The second spectral component is the light of the single-wavelength light that is refracted into the layer to be polished, reflected by the surface of the non-polished layer of the wafer, and refracted to the side of the layer to be polished away from the non-polished layer; The controller is used to perform the following processing: During the chemical mechanical polishing of the wafer, obtain the first light intensity of the target light received by the light detection module; Determine the first light intensity change waveform according to the obtained first light intensity; Predetermine the unit thickness, where the unit thickness is used to indicate the thickness change amount corresponding to the half cycle in the first light intensity change waveform; According to the target polishing thickness of the wafer during chemical mechanical polishing and the unit thickness, predict the number of half cycles of the first light intensity change waveform corresponding to reaching the end point of the polishing time from the start time to determine the end point of the polishing time, and the number of half cycles is a decimal; The unit thickness is obtained by the following method: During the chemical mechanical polishing of the wafer and before obtaining the first light intensity of the target light received by the light detection module, obtain the second light intensity of the target light received by the light detection module; Determine the second light intensity change waveform according to the obtained second light intensity; Measure the thickness difference of the layer to be polished of the wafer corresponding to the start time and the end time of at least part of the second light intensity change waveform; Determine the average thickness change amount corresponding to the half cycle in at least part of the second light intensity change waveform as the unit thickness according to the thickness difference and the number of half cycles in at least part of the second light intensity change waveform.

5. The device according to claim 4, characterized in that The chemical mechanical polishing apparatus further includes a plane mirror; The plane mirror is disposed in the cavity and is used to reflect the single-wavelength light emitted by the light emitting module to the optical window so that the light emitting module emits single-wavelength light to the optical window.

6. The apparatus according to claim 5, wherein The plane mirror is rotatably connected to the polishing platen around an axis parallel to the mirror surface of the plane mirror.

7. The device according to claim 4, characterized in that, The controller predicts the endpoint of the polishing time of the wafer according to at least part of the first light intensity change waveform, including: Determining the time difference between the start time and the end time of at least part of the first light intensity change waveform; Calculating, according to at least part of the first light intensity change waveform, the thickness difference of the layer to be polished of the wafer at the start time and the end time of at least part of the first light intensity change waveform; Determining the polishing rate according to the thickness difference and the time difference; Determining the endpoint of the polishing time for chemical mechanical polishing of the wafer according to the polishing rate and the target polishing thickness for chemical mechanical polishing of the wafer.

8. The device according to claim 7, characterized in that, The formula for calculating, by the controller, the thickness difference of the layer to be polished of the wafer at the start time and the end time of at least part of the first light intensity change waveform according to at least part of the first light intensity change waveform is as follows: ΔD = N*λ0 / (2*n*cosα), where ΔD is the thickness difference of the layer to be polished of the wafer at the start time and the end time of at least part of the first light intensity change waveform, N is the number of fluctuation periods in at least part of the first light intensity change waveform, λ0 is the wavelength of the single-wavelength light in vacuum, n is the refractive index of the layer to be polished of the wafer, and α is the refraction angle of the single-wavelength light in the layer to be polished.

9. A computer storage medium, characterized in that, A computer program is stored thereon, and when the program is executed by a processor, the method described in any one of claims 1-3 is implemented.

10. A computer program product, characterized in that, It includes computer instructions, and the computer instructions instruct a computing device to execute the method described in any one of claims 1-3.

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