Wafer grinding time prediction method and device, electronic equipment and computer storage medium

Abstract

The embodiment of the invention provides a wafer grinding time prediction method and device, electronic equipment and a computer storage medium, and the method comprises the steps that in the chemical mechanical grinding process of a wafer, the first light intensity of target light received by a light detection module is obtained, and when a light emission module emits single-wavelength light to a ground layer of the wafer, the first light intensity of the target light is equal to the first light intensity of the target light; a first split light and a second split light of the single-wavelength light are propagated through the wafer and interfere with each other to form light, and the first split light is light which is emitted to a ground layer in the single-wavelength light and is reflected on the surface of the ground layer. The second split light is light which is refracted into the ground layer, reflected by the surface of the non-ground layer of the wafer and refracted to the side, away from the non-ground layer, of the ground layer in the single-wavelength light; determining a first light intensity change waveform according to the obtained first light intensity; and according to at least part of the first light intensity change waveform, the grinding time end point of the wafer is predicted. According to the scheme, the accuracy of the grinding time end point determined in the chemical mechanical grinding process can be improved.

Description

Technical Field

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

[0002] Chemical Mechanical Polishing (CMP) is a technology used to polish wafers. It achieves flattening of the wafer surface morphology by grinding the surface layer of the wafer in a combination of mechanical and chemical methods.

[0003] At present, when determining the grinding end point during the CMP process, the grinding end point can generally be detected through optical, eddy current or drive motor current detection methods. Among them, the optical detection method is more commonly used and effective. The specific process of determining the grinding end point using the optical detection method can be as follows: Before CMP, the theoretical spectral curve when the grinding is completed should be calculated based on parameters such as the reflectivity of the grinded layer and the non-grinder layer, and during the CMP process, the spectral detection data of the grinded layer on the wafer surface should be obtained through the spectral detection equipment, so as to obtain the current actual spectral curve based on the spectral detection data, and then calculate the difference value 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 grinding end point and CMP is stopped.

[0004] However, the spectral detection equipment has strict requirements on the environment. Therefore, the consistency of the spectral detection data obtained by the spectral detection equipment under the same conditions is poor, so that the above-mentioned actual spectral curve is relatively inaccurate. Therefore, the grinding endpoint determined in the CMP process is relatively inaccurate. Summary of the invention

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

[0006] According to a first aspect of an embodiment of the present application, a method for predicting wafer grinding time is provided, comprising: obtaining a first light intensity of target light received by a light detection module during chemical mechanical grinding of a wafer, wherein the target light is light formed by first and second beamsplitting of the single-wavelength light propagating through the wafer and interfering with each other when the light transmitting module emits single-wavelength light to the polished layer of the wafer, the first beamsplitting being light emitted to the polished layer and reflected by the surface of the polished layer, and the second beamsplitting being light refracted into the polished layer, reflected by the surface of a non-polished layer of the wafer, and refracted to a side of the polished layer away from the non-polished layer; determining a first light intensity variation waveform based on the obtained first light intensity; and predicting an end point of the wafer grinding time based on at least part of the first light intensity variation waveform.

[0007] According to a second aspect of an embodiment of the present application, a chemical mechanical polishing device is provided, comprising: a grinding disc, a carrying head, a light emitting module, a light detecting module and a controller; a grinding pad is provided on one side of the grinding disc, an optical window is provided on the grinding pad and penetrates the grinding pad along the thickness direction of the grinding pad, and a cavity connected to the optical window is provided in the grinding disc; the carrying head is used to limit the wafer so that the polished layer of the wafer abuts against the grinding pad and drives the wafer to move relative to the grinding pad to perform chemical mechanical polishing on the wafer; the light emitting module is arranged 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 grinding pad away from the grinding disc; the light detecting module is arranged in the cavity and is used to detect the position of the wafer and the optical window when the wafer is in contact with the optical window. When the optical windows are opposite to each other, the controller receives the target light that is transmitted through the wafer after the single-wavelength light passes through the optical window, wherein the target light is the light formed after the first and second spectra of the single-wavelength light are transmitted through the wafer and interfere with each other, the first spectra are the light emitted to the polished layer and reflected by the surface of the polished layer in the single-wavelength light, and the second spectra are the light refracted into the polished layer, reflected by 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; the controller is used to perform the following processing: in the process of 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 based on the first light intensity that has been obtained; and predict the end point of the polishing time of the wafer based on at least part of the first light intensity change waveform.

[0008] According to a third aspect of an embodiment 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 perform the method of the first aspect.

[0009] According to a fourth aspect of an embodiment of the present application, a computer program product is provided, comprising computer instructions, wherein the computer instructions instruct a computing device to execute the method of the first aspect described above.

[0010] According to the grinding time prediction scheme provided in the embodiment of the present application, the first light intensity of the target light received by the light detection module can be obtained during the chemical mechanical grinding of the wafer, and the first light intensity change waveform can be determined based on the first light intensity that has been obtained, and then the grinding time end point of the wafer can be predicted based on at least part of the first light intensity change waveform. Therefore, in the present application, the end point of the grinding time is determined by the light intensity of the target light received by the light detection module after the light emission module emits a single wavelength of light. Compared with the scheme of determining the grinding end point by using the spectral detection data obtained by the spectral detection device, the light intensity of the target light formed by the propagation of the single wavelength of light has relatively low requirements on the environment, so that the detected first light intensity is more accurate, and then 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, thereby improving the accuracy of the grinding time end point determined during the chemical mechanical grinding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] 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.

[0012] Figure 1 is a schematic diagram of a chemical mechanical polishing device according to an embodiment of the present application; Figure 2 is a cross-sectional view of a chemical mechanical polishing device according to an embodiment of the present application; Figure 3 is a schematic diagram of single-wavelength light propagation according to an embodiment of the present application; Figure 4 is a flow chart of a method for predicting wafer grinding time according to an embodiment of the present application; Figure 5 is a schematic diagram of a first light intensity variation waveform of an embodiment of the present application; Figure 6 It is a schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0013] An embodiment of the present application provides a wafer grinding time prediction method, which is used to determine a grinding endpoint during a chemical mechanical grinding process of a wafer by a chemical mechanical grinding device.

[0014] The chemical mechanical polishing device includes a controller for executing the wafer polishing time prediction method. In a specific embodiment, Figure 1 and Figure 2 As shown, the chemical mechanical polishing device includes a grinding disc 1, a carrier head 2, a light emitting module 3, a plane reflector 4, a light detecting module 5 and a controller; a grinding pad 11 is arranged on one side of the grinding disc 1, and an optical window 111 is provided on the grinding pad 11 and penetrates the grinding pad 11 along the thickness direction of the grinding pad 11. The shape of the grinding pad 11 is a round pad. The grinding disc 1 is used to drive the grinding pad 11 to rotate around the axis of the grinding pad 11 during the chemical mechanical polishing process. A cavity 12 connected to the optical window 111 is provided in the grinding disc 1; the carrier head 2 is used to limit the wafer (the installation position of the wafer w in the carrier head 2 can be as shown in FIG. Figure 2 ), so that the polished layer of the wafer abuts against the polishing pad 11, and during the chemical mechanical polishing process, the wafer is driven to rotate around the axis of the wafer, and the wafer is driven to reciprocate along the radial direction of the polishing pad 11, so that the wafer moves relative to the polishing pad 11, thereby realizing chemical mechanical polishing of the wafer.

[0015] 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 reflector 4 is arranged in the cavity 12, and is used to target the single-wavelength light emitted by the light emitting module 3 to the optical window 111, so that the light emitting module 3 emits the single-wavelength light to the optical window 111, thereby realizing the single-wavelength light passing through the optical window 111 to the space on the side of the grinding pad 11 away from the grinding disk 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 detect the single-wavelength light emitted by the target light emitting module 3 to the optical window 111. When the wafer and the grinding pad 11 are relative to each other (that is, when the wafer and the grinding pad 11 move relative to each other until at least part of the polished layer of the wafer is covered above the optical window 111), the target light that is transmitted through the wafer after the single-wavelength light passes through the optical window 111 is received, wherein the target light is the light formed after the first and second beams of the single-wavelength light are transmitted through the wafer and interfere with each other, the first beam is the light emitted to the polished layer and reflected by the surface of the polished layer in the single-wavelength light, and the second beam is the light refracted into the polished layer in the single-wavelength light, reflected by 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.

[0016] For example, Figure 3As shown, p1 is the polished layer of the wafer, p2 is the non-polished layer of the wafer, based on this, m is the single-wavelength light reflected by the plane reflector 4, n is the first beam reflected by the surface of the polished layer of the wafer, x is the second beam refracted into the polished layer, y is the second beam reflected by the surface of the non-polished layer of the wafer, and z is the second beam refracted to the polished layer away from the non-polished layer. The controller is electrically connected to the light detection module 5 for executing the wafer polishing time prediction method, and can also be electrically connected to the light emission module 3 for controlling the emission and stopping of the single-wavelength light, etc. The embodiment of the present application does not limit the specific functions of the controller.

[0017] Based on the above chemical mechanical polishing device, a wafer polishing time prediction method is described in detail below through multiple embodiments.

[0018] Figure 4 FIG. 1 is a flow chart of a method for predicting wafer grinding time according to an embodiment of the present application. Figure 4 As shown, the wafer grinding time prediction method includes the following steps: Step 401 : During chemical mechanical polishing of a wafer, a first light intensity of a target light received by a light detection module is obtained.

[0019] Theoretically, the light intensity I of the target light received by the light detection module satisfies the following formula: I=I A +I B +2*(I A *I B )^0.5*cosφ(Formula 1), where I A is the intensity of the first split light after propagation through the wafer, I B is the intensity of the second split light after propagation through the wafer, φ is the phase difference between the first split light and the second split light, φ=(2π / λ0)*2*n*d*cosα (Formula 2), λ0 is the wavelength of single-wavelength light in vacuum, 2*n*d*cosα is the optical path difference between the first split light and the second split light, n is the refractive index of the polished layer of the wafer, and d is the thickness of the polished layer of the wafer (such as Figure 3 d in the figure), α is the refraction angle of the single wavelength light refracted into the polished layer in the polished layer (e.g. Figure 3 α in ).

[0020] In a specific embodiment, the controller may include a data acquisition module (such as Figure 2As shown), based on this, in the process of 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 a portion of the wafer is covered by the polishing layer above the optical window, the light detection module can receive the target light reflected by the wafer, and send the received analog data of the target light to the data acquisition module, and the data acquisition module can perform analog-to-digital conversion on the analog data of the target light to obtain a first light intensity of the target light, thereby realizing a solution for obtaining the first light intensity of the target light received by the light detection module.

[0021] It should be noted that at least one first light intensity can be obtained each time the wafer and the grinding pad move relative to each other until at least a portion of the wafer is covered by the grinding layer above the optical window, or at least one first light intensity can be obtained only when the wafer and the grinding pad move relative to each other partially to at least a portion of the wafer is covered by the grinding layer above the optical window. The embodiments of the present application are not limited to this.

[0022] Step 402: Determine a first light intensity variation waveform according to the acquired first light intensity.

[0023] The first light intensity variation waveform may be a continuous waveform image with time as the horizontal axis variable and the first light intensity as the vertical axis variable.

[0024] In a specific embodiment, after the chemical mechanical polishing device performs chemical mechanical polishing on the wafer for a certain period of time (the period of time can be determined based on actual needs and is not limited to this in the embodiments of the present application), the controller can obtain multiple first light intensities and the time when the target light corresponding to each first light intensity is received by the light detection module. At this time, based on 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 horizontal axis variable and the first light intensity as the vertical axis variable can be fitted, which is the first light intensity change waveform.

[0025] Based on the above formula of light intensity I, during the process of 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 emitting module is relatively constant and the material of the polishing layer is fixed, the I in the above formula 1 is A and I Bis almost 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, due to the existence of the only variable d in formula 2, since the polishing speed of the wafer is basically constant during the chemical mechanical polishing process, the decreasing rate of d in formula 2 during the chemical mechanical polishing process is relatively constant, so that φ basically decreases gradually at a uniform speed during the chemical mechanical polishing process. Based on this, the cosφ in formula 1 changes with the wafer thickness more regularly during the chemical mechanical polishing process, that is, if the waveform of cosφ changing with the wafer thickness during the chemical mechanical polishing process is fitted, the wafer thickness change corresponding to each half cycle in the waveform (a half cycle is the part between adjacent peaks and troughs in the corresponding waveform, that is, the part from the peak to the adjacent trough and the part from the trough to the adjacent peak in the waveform are both one and a half cycles) is almost the same, and further, the wafer thickness change corresponding to each half cycle in the first light intensity change waveform corresponding to I during the chemical mechanical polishing process is almost the same.

[0026] Step 403: predicting an end point of the wafer polishing time based on at least a portion of the first light intensity variation waveform.

[0027] In a specific embodiment, considering that the wafer thickness variation corresponding to each half cycle in the first light intensity variation waveform is almost the same, the first light intensity variation waveform can be used to determine the law of the thickness of the polished layer of the wafer changing with the first light intensity variation waveform during the chemical mechanical polishing of the wafer, and then during the wafer processing, the controller can include a data processing module (such as Figure 2 As shown), based on this, when the data acquisition module obtains the first light intensity change waveform, the first light intensity change waveform can be sent to the data processing module, and the data processing module then selects at least a portion of the continuous first light intensity change waveform from the first light intensity change waveform to determine the corresponding acquisition time, and combines the rule to predict the end point of the wafer grinding time.

[0028] In an embodiment of the present application, during the chemical mechanical polishing of the wafer, the first light intensity of the target light received by the light detection module can be obtained, and based on the first light intensity that has been obtained, the first light intensity change waveform can be determined, and then the end point of the polishing time of the wafer can be predicted based on at least part of the first light intensity change waveform. Therefore, in the present application, after the light emitting module emits single-wavelength light, the light intensity of the target light received by the light detection module determines the end point of the polishing time. Compared with the scheme of determining the end point of the polishing by using the spectral detection data obtained by the spectral detection device, the light intensity of the target light formed by the propagation of single-wavelength light has relatively low requirements on the environment, and the detected first light intensity is more accurate. Then, 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 end point of the polishing time determined during the chemical mechanical polishing process can be improved.

[0029] In addition, compared with detecting the end point of the grinding time by eddy current during the chemical mechanical grinding process, the wafer grinding time prediction method in the present application can be applied to any dielectric layer material whose grinding layer can reflect and refract light, and has a wider range of applications.

[0030] The above step 403 can be implemented in at least the following two ways: 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 the above at least part of the first light intensity variation waveform; calculating the thickness difference of the polished layer of the wafer at the start time and the end time of the above at least part of the first light intensity variation waveform based on the above at least part of the first light intensity variation waveform; determining the polishing rate based on the thickness difference and the time difference; determining the end point of the polishing time for chemical mechanical polishing of the wafer based on the polishing rate and the target polishing thickness for chemical mechanical polishing of the wafer.

[0031] For example, the first light intensity variation waveform is as follows: Figure 5 As shown, at least part of the first light intensity variation waveform is Figure 5 Based on the waveform H in, the time difference between the start time and the end time of H can be obtained, and the thickness difference of the polished layer of the wafer at the start time and the end time of H can be calculated, and then the polishing rate v can be determined according to the time difference and the thickness difference. Based on this, before chemical mechanical polishing of the wafer, the target polishing thickness S of the wafer (that is, the polishing amount of the wafer) can be determined, and then the end point of the polishing time for chemical mechanical polishing of the wafer can be determined as the time point after the start of polishing for a period of time, time=S / v.

[0032] Therefore, when determining the end point of the grinding time for chemical mechanical grinding of the wafer, it can be directly calculated according to the grinding rate and the target grinding thickness, the processing logic is simple, and computing resources are saved.

[0033] Optionally, the formula for determining the grinding rate based on the thickness difference and the time difference is as follows: RR=ΔD / Δt, wherein RR is the grinding rate, ΔD is the thickness difference of the grinding layer of the wafer at the start time and the end time of the above-mentioned at least part of the first light intensity variation waveform, and Δt is the above-mentioned time difference.

[0034] Optionally, the formula for calculating the thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform according to the at least part of the first light intensity variation waveform is as follows: ΔD=N*λ0 / (2*n*cosα), wherein ΔD is the thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform, N is the number of fluctuation periods in the at least part of the first light intensity variation 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.

[0035] Therefore, compared with obtaining the thickness difference of the polished layer of the wafer at the start time and the end time of at least part of the first light intensity change waveform by measuring, the thickness difference can be obtained by calculation in the present application, which is more convenient and improves the efficiency of determining the end point of the polishing time.

[0036] In another possible implementation, the above step 403 includes the following specific processing: predetermining the unit thickness, wherein the unit thickness is used to indicate the thickness change corresponding to each half-cycle in the first light intensity change waveform, and the half-cycle can be the portion between adjacent peaks and troughs in the corresponding waveform; based on the target grinding thickness for chemical mechanical grinding of the wafer and the unit thickness, predicting the number of half-cycles of the first light intensity change waveform corresponding to the start time to the end time of the grinding time to determine the end time of the grinding time.

[0037] In a specific embodiment, after determining the unit thickness, in the process of chemically mechanically polishing the wafer and obtaining the first light intensity, the number of half cycles num=S / Δd in the first light intensity change waveform when the target polishing thickness is reached can be calculated and determined as the polishing time end point for chemically mechanical polishing the wafer, Δd is the unit thickness, and S is the target polishing thickness. It should be noted that the number of half cycles in the present application can be an integer or a decimal, that is, it can be located at a specific point within the half cycle, ensuring the accuracy of the determined polishing time end point.

[0038] Therefore, when determining the end point of the chemical mechanical polishing time of the wafer, it is achieved by counting the half cycles during the chemical mechanical polishing of the wafer, so that the current polished thickness of the wafer can be obtained, and the polishing condition of the wafer can be monitored more accurately.

[0039] Optionally, the number of half cycles in the first light intensity change waveform can be counted from the Lth peak or trough in the first light intensity change waveform, so that the more accurate part of the first light intensity change waveform can be processed by half-cycle counting, thereby improving the accuracy of the determined grinding end point. L can be set according to actual needs and can be directly subtracted when calculating the number of half cycles. The embodiment of the present application is not limited to this.

[0040] by Figure 5 For example, the more accurate part of the first light intensity variation waveform can start from the starting point of H, and the determined half-cycle number num=4.4, then the half-cycles are counted from the starting point of H to determine that the end point of H is reached after 4.4 half-cycles, that is, the grinding end point.

[0041] Optionally, the above unit thickness can be obtained by any one of the following two possible implementation methods.

[0042] In a possible implementation manner, the input unit thickness is obtained.

[0043] For example, the staff can calculate the unit thickness based on the actual measured wafer parameters, or the staff can perform chemical mechanical grinding 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 corresponding to each half cycle in the light intensity change waveform as the above-mentioned unit thickness. Afterwards, the staff can input the unit thickness into the controller, or pre-set it in the controller's application program so that the controller obtains the input unit thickness. Among them, the experimental bench can be a simple construction that simulates a chemical mechanical grinding device or a real and complete chemical mechanical grinding device, and the embodiments of the present application are not limited to this.

[0044] 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 polished layer of the wafer, and α is the refraction angle of the single-wavelength light in the polished layer.

[0045] In another possible implementation, during chemical mechanical polishing of a wafer, and before obtaining a first light intensity of the target light received by the light detection module, a second light intensity of the target light received by the light detection module is obtained; a second light intensity variation waveform is determined based on the obtained second light intensity; 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 variation waveform is measured; and based on the thickness difference and the number of half cycles in at least part of the second light intensity variation waveform, an average thickness change corresponding to each half cycle in at least part of the second light intensity variation waveform is determined as the unit thickness.

[0046] Among them, the specific method of obtaining the second light intensity is the same as the specific method of obtaining the first light intensity in the previous text, and the specific method of determining the second light intensity change waveform is the same as the specific method of determining the first light intensity change waveform in the previous text, and the embodiments of the present application will not be repeated here.

[0047] For example, the at least partial second light intensity variation waveform includes approximately 2.2 fluctuation cycles, or 4.4 half cycles. Based on this, the average thickness change Δd=ΔD2 / 4.4 corresponding to each half cycle in the at least partial second light intensity variation waveform can be determined according to the thickness difference ΔD2 of the polished layer of the wafer at the start time and the end time of the at least partial second light intensity variation waveform, and the Δd can be used as the unit thickness.

[0048] Therefore, compared with obtaining 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 by measuring, the thickness difference can be obtained by calculation in the present application, which is more convenient and improves the efficiency of determining the polishing end point.

[0049] Optionally, the wafers targeted by the first light intensity variation waveform and the second light intensity variation waveform may be the same wafer, or may be wafers with the same wafer model, size and structure (for example, wafers of the same model and from the same batch), and this embodiment of the present application does not limit this.

[0050] Corresponding to the above method embodiment, the present application embodiment also provides a chemical mechanical polishing device, such as Figure 1 and Figure 2 As shown, the chemical mechanical polishing device includes: a polishing disc 1, a carrier head 2, a light emitting module 3, a light detecting module 5 and a controller; A grinding pad 11 is disposed on one side of the grinding disc 1. An optical window 111 is provided on the grinding pad 11 and penetrates the grinding pad 11 along the thickness direction of the grinding pad 11. A cavity 12 is provided in the grinding disc 1 and communicates with the optical window 111. The carrier head 2 is used to position the wafer so that the polished layer of the wafer abuts against the polishing pad 11, and drives the wafer to move relative to the polishing pad 11 to perform chemical mechanical polishing on the wafer; The light emitting module 3 is disposed in the cavity 12 and is used to emit 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 disc 1; The optical detection module 5 is arranged in the cavity 12, and is used for receiving the target light propagated through the wafer after the single-wavelength light passes through the optical window 111 when the wafer is opposite to the optical window 111, wherein the target light is the light formed after the first split light and the second split light of the single-wavelength light propagate through the wafer and interfere with each other, the first split light is the light emitted 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 by 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; The controller is used to perform the following processing: During chemical mechanical polishing of the wafer, obtaining a first light intensity of the target light received by the light detection module 5; Determine a first light intensity variation waveform according to the acquired first light intensity; An end point of the wafer polishing time is predicted based on at least a portion of the first light intensity variation waveform.

[0051] In a possible implementation, the chemical mechanical polishing device also includes a plane reflector 4; the plane reflector 4 is arranged in the cavity 12, and is used to reflect the single wavelength light emitted by the light emitting module 3 to the optical window 111, so that the light emitting module 3 emits the single wavelength light to the optical window 111.

[0052] In one possible implementation, the plane mirror 4 is rotatably connected to the grinding disc 1 around an axis parallel to the mirror surface of the plane mirror 4. Thus, the angle of emission of single-wavelength light to the optical window 111 can be adjusted by rotating the plane mirror 4 relative to the grinding disc 1, thereby improving the adjustability and fault tolerance of the chemical mechanical polishing device.

[0053] In a possible implementation, the controller predicts the end point of the polishing time of the wafer according to at least part of the first light intensity variation waveform, including: Determine the time difference between the start time and the end time of at least part of the first light intensity variation waveform; According to the at least part of the first light intensity variation waveform, a thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform is calculated; Determine the grinding rate based on the thickness difference and the time difference; An end point of the polishing time for chemical mechanical polishing of the wafer is determined according to the polishing rate and the target polishing thickness of the wafer for chemical mechanical polishing.

[0054] In a possible implementation, the controller executes the following formula to calculate the thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform according to the at least part of the first light intensity variation waveform: ΔD=N*λ0 / (2*n*cosα), wherein ΔD is the thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform, N is the number of fluctuation periods in the at least part of the first light intensity variation waveform, λ0 is the wavelength of 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 refracted into the polished layer in the polished layer.

[0055] In a possible implementation, the controller predicts the end point of the polishing time of the wafer according to at least part of the first light intensity variation waveform, including: Predetermine a unit thickness, wherein the unit thickness is used to indicate the thickness variation corresponding to each half cycle in the first light intensity variation waveform, and the half cycle is the portion between adjacent peaks and troughs in the corresponding waveform; According to the target grinding thickness and unit thickness of the wafer during chemical mechanical grinding, the number of half cycles of the first light intensity variation waveform corresponding to the start time to the end time of the grinding is predicted to determine the end time of the grinding.

[0056] In a possible implementation, the unit thickness is obtained by one of the following methods: Get the input unit thickness; or, During chemical mechanical polishing of a wafer, and before obtaining a first light intensity of the target light received by the light detection module, a second light intensity of the target light received by the light detection module is obtained; based on the obtained second light intensity, a second light intensity variation waveform is determined; 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 variation waveform is measured; based on the thickness difference and the number of half cycles in the at least part of the second light intensity variation waveform, an average thickness change corresponding to each half cycle in the at least part of the second light intensity variation waveform is determined as the unit thickness.

[0057] In a possible implementation, the controller executes the following formula to calculate the thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the second light intensity variation waveform based on at least part of the second light intensity variation waveform: The specific structure of the chemical polishing equipment has been described in the method embodiment and will not be repeated here in the embodiment of the present application.

[0058] 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 aforementioned method embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be repeated here.

[0059] Figure 6 This is a schematic block diagram of an electronic device provided in an embodiment of the present application. The specific embodiment of the present application does not limit the specific implementation of the electronic device. Figure 6 As shown, the electronic device may include: a processor (processor) 602, a communication interface (Communications Interface) 604, a memory (memory) 606, and a communication bus 608. Among them: The processor 602 , the communication interface 604 , and the memory 606 communicate with each other via a communication bus 608 .

[0060] The communication interface 604 is used to communicate with other electronic devices or servers.

[0061] The processor 602 is used to execute the program 610, and specifically can execute the relevant steps in any of the aforementioned wafer grinding time prediction method embodiments.

[0062] Specifically, the program 610 may include program codes, which include computer operation instructions.

[0063] The processor 602 may be a CPU, or an application specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application. The one or more processors included in the smart device may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0064] RISC-V is an open source instruction set architecture based on the Reduced Instruction Set (RISC) principle. It can be applied to various aspects such as single-chip microcomputers and FPGA chips. Specifically, it can be applied to the fields of IoT security, industrial control, mobile phones, personal computers, etc., and because it is designed with small, fast, and low-power realities in mind, 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 also received more and more attention and support, and is expected to become the next generation of widely used CPU architecture.

[0065] The computer operation instructions in the embodiment of the present application may be computer operation instructions based on the RISC-V instruction set architecture, and correspondingly, the processor 602 may be designed based on the RISC-V instruction set. Specifically, the processor chip in the electronic device provided in the embodiment of the present application may be a chip designed using the RISC-V instruction set, and the chip may execute executable code based on the configured instructions, thereby realizing the wafer grinding time prediction method in the above embodiment.

[0066] The memory 606 is used to store the program 610. The memory 606 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0067] The program 610 may be specifically used to enable the processor 602 to execute the wafer grinding time prediction method in any of the aforementioned embodiments.

[0068] The specific implementation of each step in program 610 can refer to the corresponding description of the corresponding steps and units in any of the aforementioned wafer grinding time prediction method embodiments, which will not be repeated here. A person skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the above-described equipment and modules can refer to the corresponding process description in the aforementioned method embodiment, which will not be repeated here.

[0069] 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 a storage medium can be provided, on which a software program code for implementing the functions of any of the above-mentioned embodiments is stored, and a computer (or CPU or MPU) of the system or device reads out and executes the program code stored in the storage medium.

[0070] In this case, the program code read from the storage medium itself can implement the function of any one of the above embodiments, so the program code and the storage medium storing the program code constitute part of the present application.

[0071] The storage medium embodiments for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer via a communication network.

[0072] An embodiment of the present application also provides a computer program product, including computer instructions, which instruct a computing device to perform any corresponding operation in the above-mentioned multiple method embodiments.

[0073] It should be noted that the user-related information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data used to train the model, data used for analysis, stored data, displayed data, etc.) involved in the embodiments of the present application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0074] 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.

[0075] 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 special-purpose processor or programmable or special-purpose 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 (e.g., 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 a computer, a processor or hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown here, the execution of the code converts the general-purpose computer into a special-purpose computer for executing the method shown here.

[0076] It should be noted that the user-related information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to sample data used to train the model, data used for analysis, stored data, displayed data, etc.) involved in the embodiments of the present application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0077] 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 specific applications, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0078] 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 wafer grinding time prediction method, characterized in that: include: During chemical mechanical polishing of a wafer, a first light intensity of a target light received by a light detection module is obtained, wherein the target light is light formed when a light emitting module emits a single-wavelength light to a polished layer of the wafer, and a first light spectrum and a second light spectrum of the single-wavelength light are propagated through the wafer and interfere with each other, the first light spectrum is light emitted from the single-wavelength light to the polished layer and reflected by the surface of the polished layer, and the second light spectrum is light refracted from the single-wavelength light into the polished layer, reflected by the surface of a non-polished layer of the wafer, and refracted to a side of the polished layer away from the non-polished layer; Determining a first light intensity variation waveform according to the acquired first light intensity; An end point of the wafer polishing time is predicted based on at least a portion of the first light intensity variation waveform.

2. The method according to claim 1, characterized in that The method of predicting the end point of the wafer polishing time according to at least part of the first light intensity variation waveform comprises: Determining a time difference between a start time and an end time of at least a portion of the first light intensity variation waveform; Calculating, according to the at least part of the first light intensity variation waveform, a thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform; determining a grinding rate according to the thickness difference and the time difference; The end point of the polishing time for chemical mechanical polishing of the wafer is determined according to the polishing rate and the target polishing thickness for chemical mechanical polishing 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 start time and the end time of the at least part of the first light intensity variation waveform according to the at least part of the first light intensity variation waveform is as follows: ΔD=N*λ0 / (2*n*cosα), wherein ΔD is the thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform, N is the number of fluctuation periods in the at least part of the first light intensity variation 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. The method according to claim 1, characterized in that: The method of predicting the end point of the polishing time of the wafer according to at least part of the first light intensity variation waveform comprises: predetermining a unit thickness, wherein the unit thickness is used to indicate a thickness variation corresponding to a half period in the first light intensity variation waveform; According to the target grinding thickness of the wafer subjected to chemical mechanical grinding and the unit thickness, the number of half cycles of the first light intensity variation waveform corresponding to the start time to the end time of the grinding is predicted to determine the end time of the grinding.

5. The method according to claim 4, characterized in that The unit thickness is obtained by one of the following methods: Obtain the input unit thickness; or, In the process of chemical mechanical polishing of the wafer, and before acquiring the first light intensity of the target light received by the light detection module, acquiring the second light intensity of the target light received by the light detection module; determining the second light intensity variation waveform according to the acquired second light intensity; and measuring 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 variation waveform; According to the thickness difference and the number of half cycles in the at least part of the second light intensity variation waveform, an average thickness variation corresponding to the half cycle in the at least part of the second light intensity variation waveform is determined as the unit thickness.

6. A chemical mechanical polishing device, characterized in that: include: A grinding disc, a carrier head, a light emitting module, a light detecting module and a controller; A grinding pad is disposed on one side of the grinding disc, an optical window is provided on the grinding pad and penetrates the grinding pad along the thickness direction of the grinding pad, and a cavity connected to the optical window is provided in the grinding disc; The carrier head is used to limit the position of the wafer so that the polished layer 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 toward the optical window, so that the single-wavelength light passes through the optical window and is emitted toward a side of the polishing pad away from the polishing disk; The optical detection module is arranged in the cavity, and is used for receiving 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, wherein the target light is the light formed after the first and second split beams of the single-wavelength light propagate through the wafer and interfere with each other, the first split beam is the light emitted to the polished layer and reflected by the surface of the polished layer in the single-wavelength light, and the second split beam is the light refracted into the polished layer, reflected by 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; The controller is used to perform the following processing: During chemical mechanical polishing of the wafer, obtaining a first light intensity of the target light received by the light detection module; Determining a first light intensity variation waveform according to the acquired first light intensity; An end point of the wafer polishing time is predicted based on at least a portion of the first light intensity variation waveform.

7. The device according to claim 6, characterized in that The chemical mechanical polishing device also includes a plane reflecting mirror; The plane reflector is arranged 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 the single-wavelength light to the optical window.

8. The device according to claim 7, characterized in that The plane reflector is rotatably connected to the grinding disk around an axis parallel to the mirror surface of the plane reflector.

9. The device according to claim 6, characterized in that The controller predicts the end point of the polishing time of the wafer according to at least part of the first light intensity variation waveform, including: Determining a time difference between a start time and an end time of at least a portion of the first light intensity variation waveform; Calculating, according to the at least part of the first light intensity variation waveform, a thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform; determining a grinding rate according to the thickness difference and the time difference; The end point of the polishing time for chemical mechanical polishing of the wafer is determined according to the polishing rate and the target polishing thickness for chemical mechanical polishing of the wafer.

10. The device according to claim 9, characterized in that The controller executes the following formula to calculate the thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform according to the at least part of the first light intensity variation waveform: ΔD=N*λ0 / (2*n*cosα), wherein ΔD is the thickness difference of the polished layer of the wafer at the start time and the end time of the at least part of the first light intensity variation waveform, N is the number of fluctuation periods in the at least part of the first light intensity variation 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.

11. The device according to claim 6, characterized in that The controller predicts the end point of the polishing time of the wafer according to at least part of the first light intensity variation waveform, including: predetermining a unit thickness, wherein the unit thickness is used to indicate a thickness variation corresponding to a half period in the first light intensity variation waveform; According to the target grinding thickness of the wafer subjected to chemical mechanical grinding and the unit thickness, the number of half cycles of the first light intensity variation waveform corresponding to the start time to the end time of the grinding is predicted to determine the end time of the grinding.

12. The device according to claim 11, characterized in that The unit thickness is obtained by one of the following methods: Obtain the input unit thickness; or, In the process of chemical mechanical polishing of the wafer, and before acquiring the first light intensity of the target light received by the light detection module, acquiring the second light intensity of the target light received by the light detection module; determining the second light intensity variation waveform according to the acquired second light intensity; and measuring 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 variation waveform; According to the thickness difference and the number of half cycles in the at least part of the second light intensity variation waveform, an average thickness variation corresponding to the half cycle in the at least part of the second light intensity variation waveform is determined as the unit thickness.

13. A computer storage medium, characterized in that: A computer program is stored thereon, and when the program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

14. A computer program product, characterized in that The method comprises computer instructions for instructing a computing device to execute the method according to any one of claims 1 to 5.

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