Wafer thinning apparatus and thinning method

Abstract

The application provides a wafer thinning device and a thinning method. The method comprises the following steps: acquiring actual characteristic parameters of an arch-shaped wave of a cooling liquid in a wafer thinning process by using a schlieren method; obtaining a heat dissipation index and a wear index of a grinding wheel based on the actual characteristic parameters and reference characteristic parameters under a normal working condition; and adjusting a wafer thinning process in real time based on the heat dissipation index and the wear index. The wafer thinning device and the thinning method provided by the application can indirectly and in real time acquire the heat dissipation and wear information of the grinding wheel by detecting the arch-shaped wave of the cooling liquid by using the schlieren method, so that the health condition of the grinding wheel can be evaluated in real time and the wafer thinning process can be adjusted in real time, thereby ensuring the stability of the wafer processing process and improving the wafer processing efficiency.

Description

Technical Field

[0001] This application relates to the field of wafer grinding equipment inspection technology, and in particular to a wafer thinning equipment and thinning method. Background Technology

[0002] Three-dimensional integrated circuits (3D ICs) are an important technological path for the semiconductor industry to continue Moore's Law and improve chip performance and integration. The core idea is to stack multiple chips or functional layers vertically and achieve interlayer electrical connections through interconnection technologies such as through-silicon vias (TSVs), thereby achieving higher functional density within a limited space.

[0003] Wafer thinning is a key supporting process in 3D IC manufacturing, its main purpose being to reduce the wafer's thickness from its original level to an ultra-thin state suitable for vertical integration. Ultra-thin wafers are the physical basis for 3D stacking and are crucial for optimizing electrical performance and thermal management. As the number of 3D IC stacking layers increases, the requirements for the thinning thickness of individual wafers become increasingly stringent. Simultaneously, 3D IC technology places extremely high demands on the surface quality of the thinned wafer, including excellent Total Thickness Variation (TTV) and extremely low Roughness Average (Ra), to ensure the accuracy, consistency, and stability of subsequent bonding processes.

[0004] To achieve the aforementioned thinning targets, wafer thinning equipment typically utilizes the physical grinding action of grinding wheels to process ultra-thin wafers. Such equipment must have its grinding structure and grinding process precisely designed and controlled to meet the requirements for ultra-thin wafer processing (such as thickness ≤10μm, TTV ≤1.5μm, and Ra ≤5nm) while also considering manufacturing costs and production efficiency.

[0005] During wafer thinning, grinding debris easily clogs the pores of the grinding wheel, reducing its porosity, hindering coolant flow, increasing heat accumulation, and impairing heat dissipation. Simultaneously, wheel wear leads to changes in the bottom surface morphology, easily causing an imbalance between the wheel's self-sharpening and durability. Therefore, monitoring the condition of the grinding wheel and estimating its remaining lifespan (health) are particularly important during wafer thinning.

[0006] Currently, industrial CT inspection is commonly used to inspect the grinding wheels required in wafer thinning. However, this inspection method requires the removal of the grinding wheel (i.e., non-in-situ inspection), which significantly impacts production efficiency. Furthermore, this method can only inspect a local area, and the entire surface of the grinding wheel needs to be characterized by synthesis, which is cumbersome and has low precision. Moreover, due to the large size of the grinding wheel, it is sometimes necessary to destroy the wheel to fit certain inspection equipment, thus failing to achieve non-destructive testing. Finally, because this inspection method is non-in-situ, it is impossible to adjust the grinding process parameters in real time and accurately, resulting in the surface quality of the processed wafer failing to meet the predetermined requirements, ultimately leading to a decrease in chip yield. Summary of the Invention

[0007] In view of this, this application provides a wafer thinning apparatus and a thinning method to solve at least one of the aforementioned problems.

[0008] To achieve the above objectives, this application adopts the following approach:

[0009] According to a first aspect of this application, a wafer thinning method is provided, the method comprising: obtaining actual characteristic parameters of the coolant bow-shaped wave during the wafer thinning process using schlieren method; obtaining the heat dissipation index and wear index of the grinding wheel based on the actual characteristic parameters and the reference characteristic parameters under normal operating conditions; and adjusting the wafer thinning process in real time based on the heat dissipation index and wear index.

[0010] As an embodiment of this application, the method described above for obtaining the actual characteristic parameters of the coolant bow wave during wafer thinning using schlieren includes: capturing the bow wave of the coolant ejected during wafer thinning using a single-mirror coaxial optical path of a schlieren device; the components of the single-mirror coaxial optical path include a light source disposed below the ejected coolant, a beam splitter on the wafer grinding chamber cover, and a schlieren camera above the beam splitter; and processing the bow wave to extract the actual characteristic parameters.

[0011] As an embodiment of this application, the above-mentioned actual characteristic parameters and reference characteristic parameters include: wave crest angle, wave amplitude and wavefront curvature.

[0012] As an embodiment of this application, the above-mentioned method of obtaining the heat dissipation index and wear index of the grinding wheel based on the actual characteristic parameters and the reference characteristic parameters under normal working conditions includes: obtaining the heat dissipation index of the grinding wheel by adjusting the wave crest angle and wave amplitude in the reference characteristic parameters and the actual characteristic parameters through temperature compensation factor and / or time decay factor; and obtaining the wear index of the grinding wheel by adjusting the wave crest angle and wave front curvature in the reference characteristic parameters and the actual characteristic parameters.

[0013] As an embodiment of this application, the above-mentioned adjustment of the wafer thinning process in real time based on the heat dissipation index and the wear index includes: comparing the heat dissipation index with multiple preset heat dissipation state thresholds, and obtaining the corresponding process adjustment strategy according to the comparison results to perform process adjustment; comparing the wear index with multiple preset wear state thresholds, and obtaining the corresponding grinding wheel dressing strategy according to the comparison results to perform grinding wheel dressing and / or process adjustment.

[0014] As an embodiment of this application, before obtaining the actual characteristic parameters of the coolant bow-shaped wave during wafer thinning using the schlieren method, the method further includes: performing non-destructive in-situ testing on the grinding wheel to obtain the porosity of the grinding wheel; determining whether online monitoring is required based on the porosity; if monitoring is required, obtaining the actual characteristic parameters of the coolant bow-shaped wave during wafer thinning using the schlieren method.

[0015] As an embodiment of this application, the above method further includes: obtaining corresponding in-situ detection health, heat dissipation health, and wear health based on porosity, heat dissipation health, and wear health, respectively; and obtaining in-situ detection health (H1) and heat dissipation health (H2) based on the in-situ detection health (H1) and wear health (H2) index. c ) and wear and tear health (H) w To obtain the grinding wheel health (LI): LI = 0.2H1 + 0.4H c +0.4H w The need for grinding wheel dressing or replacement is determined based on the condition of the grinding wheel.

[0016] As an embodiment of this application, the above method further includes: obtaining an assessment value of the remaining service life of the grinding wheel based on the grinding wheel health status using a grinding wheel life assessment model; the grinding wheel life assessment model is as follows:

[0017] ;

[0018] Among them, T remain T represents the remaining useful life assessment value. total =500h, e -λt λ is the time decay factor, where t is the actual machine time and λ is the decay coefficient.

[0019] As an embodiment of this application, the above-mentioned non-destructive in-situ testing of the grinding wheel to obtain the porosity of the grinding wheel includes: measuring the propagation and scattering characteristics of light waves in the grinding wheel to determine the first porosity of the grinding wheel; measuring the propagation and scattering characteristics of sound waves in the grinding wheel to determine the second porosity of the grinding wheel; and weightedly fusing the first porosity and the second porosity to obtain a third porosity as the porosity of the grinding wheel.

[0020] As an embodiment of this application, the above-mentioned determination of whether online monitoring is required based on porosity includes: determining whether the third porosity is within a preset range; if not, online monitoring is required.

[0021] According to a second aspect of this application, a wafer thinning apparatus is provided, comprising: a schlieren device for obtaining actual characteristic parameters of the bow-shaped wave of the coolant during the wafer thinning process using the schlieren method; an index acquisition unit for obtaining the heat dissipation index and wear index of the grinding wheel based on the actual characteristic parameters and the reference characteristic parameters under normal operating conditions; and a process control unit for controlling the adjustment of the wafer thinning process in real time based on the heat dissipation index and wear index.

[0022] As an embodiment of this application, the above-mentioned schlieren device is specifically used to: capture the bow-shaped wave of the coolant ejected during the wafer thinning process using the single-mirror coaxial optical path of the schlieren device, wherein the components of the single-mirror coaxial optical path include a light source disposed below the ejected coolant, a beam splitter on the wafer grinding chamber cover, and a schlieren camera above the beam splitter; and process the bow-shaped wave to extract actual feature parameters.

[0023] As an embodiment of this application, the above-mentioned actual characteristic parameters and reference characteristic parameters include: wave crest angle, wave amplitude and wavefront curvature.

[0024] As an embodiment of this application, the above-mentioned index acquisition unit includes: a heat dissipation index acquisition module, used to obtain the heat dissipation index of the grinding wheel by adjusting the peak angle and amplitude in the reference characteristic parameters and actual characteristic parameters through a temperature compensation factor and / or a time decay factor; and a wear index acquisition module, used to obtain the wear index of the grinding wheel by adjusting the peak angle and wavefront curvature in the reference characteristic parameters and actual characteristic parameters.

[0025] As an embodiment of this application, the above-mentioned process control unit includes: a first adjustment module, used to compare the heat dissipation index with a plurality of preset heat dissipation state thresholds, and obtain a corresponding process adjustment strategy based on the comparison result to perform process adjustment; and a second adjustment module, used to compare the wear index with a plurality of preset wear state thresholds, and obtain a corresponding grinding wheel dressing strategy based on the comparison result to perform grinding wheel dressing and / or process adjustment.

[0026] As an embodiment of this application, the above-mentioned device further includes: a detection unit for performing non-destructive in-situ detection on the grinding wheel to obtain the porosity of the grinding wheel; and a judgment unit for determining whether online monitoring is required based on the porosity, and if detection is required, using the schlieren method to obtain the actual characteristic parameters of the coolant bow wave during the wafer thinning process.

[0027] As an embodiment of this application, the above-mentioned device further includes: a first health acquisition unit, used to obtain corresponding in-situ detection health, heat dissipation health, and wear health based on porosity, heat dissipation health, and wear health, respectively; and a second health acquisition unit, used to obtain in-situ detection health (H1) and heat dissipation health (H2) based on porosity, heat dissipation health (H3) and wear health (H4) respectively. c ) and wear and tear health (H) w To obtain the grinding wheel health (LI): LI = 0.2H1 + 0.4H c +0.4H w The grinding wheel adjustment unit is used to determine whether grinding wheel dressing or replacement is needed based on the condition of the grinding wheel.

[0028] As an embodiment of this application, the above-mentioned device further includes: a life assessment unit, used to obtain an assessment value of the remaining service life of the grinding wheel based on the grinding wheel health status and using a grinding wheel life assessment model; the grinding wheel life assessment model is:

[0029] ;

[0030] Among them, T remain T represents the remaining useful life assessment value. total =500h, e -λt λ is the time decay factor, where t is the actual machine time and λ is the decay coefficient.

[0031] As an embodiment of this application, the above-mentioned detection unit includes: a light wave detection module for measuring the propagation and scattering characteristics of light waves in the grinding wheel to determine the first porosity of the grinding wheel; a sound wave detection module for measuring the propagation and scattering characteristics of sound waves in the grinding wheel to determine the second porosity of the grinding wheel; and a weighted fusion module for weighted fusion of the first porosity and the second porosity to obtain a third porosity as the porosity of the grinding wheel.

[0032] As an embodiment of this application, the above-mentioned judgment unit is specifically used to: determine whether the third porosity is within a preset range; if not, online monitoring is required.

[0033] According to a third aspect of this application, a wafer thinning apparatus is provided, comprising: an adsorption platform for supporting and rotating a wafer; a grinding device, which is raised and lowered above the adsorption platform, the lower part of which has a grinding wheel for grinding the wafer; a light source located below one side of the adsorption platform; and a schlieren camera located above one side of the adsorption platform, facing the light source, for acquiring coolant bow-shaped waves; the coolant bow-shaped waves are used to determine the heat dissipation index and wear index of the grinding wheel, so as to control the wafer thinning process in real time.

[0034] As an embodiment of this application, the above-mentioned device further includes: a turntable for rotating to drive the adsorption platform to change position, the turntable having a window for placing the adsorption platform, and the upper surface of the adsorption platform being higher than the window plane.

[0035] As an embodiment of this application, the above-mentioned device further includes: a turntable cover, which is disposed on the turntable to form a grinding chamber between the turntable and the turntable, and a viewing window is provided on the turntable cover at a position corresponding to the position above the light source.

[0036] As an embodiment of this application, the above-mentioned device further includes: a windshield wiper, disposed below the viewing window, with one end connected to the side wall of the turntable cover, for removing coolant from the viewing window.

[0037] As an embodiment of this application, the above-mentioned device further includes: a support rod, one end of which is connected to the center of the turntable and the other end of which is connected to the schlieren camera, for fixing the schlieren camera.

[0038] As an embodiment of this application, the above-mentioned device further includes: a beam splitter, disposed above the viewing window, located between the light source and the schlieren camera.

[0039] According to a fourth aspect of this application, embodiments of this application also provide a wafer thinning apparatus, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the wafer thinning method described above.

[0040] According to a fifth aspect of this application, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0041] According to a sixth aspect of this application, a computer-readable storage medium is provided that stores a computer program thereon, which, when executed by a processor, implements the steps of the above-described method.

[0042] As can be seen from the above technical solutions, the wafer thinning equipment and thinning method provided in this application use schlieren to detect the bow wave of the coolant, which can indirectly obtain the heat dissipation and wear information of the grinding wheel in real time. This allows for real-time evaluation of the grinding wheel's grinding capability to adjust the wafer thinning process in real time, ensuring the stability of the wafer processing process and improving wafer processing efficiency and the yield of the final chip. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0044] Figure 1 This is a schematic flowchart of a wafer thinning method provided in an embodiment of this application;

[0045] Figure 2 This is a schematic diagram of the process for obtaining feature parameters provided in this embodiment;

[0046] Figure 3 This is a schematic diagram showing the positions of the three characteristic parameters provided in the embodiments of this application on the bow-shaped wave waveform;

[0047] Figure 4 This is a schematic diagram of the process for obtaining the heat dissipation index and wear index of the grinding wheel according to an embodiment of this application;

[0048] Figure 5 This is a flowchart illustrating the process of obtaining baseline characteristic parameters under normal operating conditions, provided in an embodiment of this application.

[0049] Figure 6 This is a flowchart illustrating the acquisition of actual characteristic parameters under measured working conditions provided in the embodiments of this application;

[0050] Figure 7 This is a schematic diagram of the real-time control of wafer thinning process adjustment provided in the embodiments of this application;

[0051] Figure 8 The embodiments of this application provide a flowchart of the online monitoring value determination logic;

[0052] Figure 9 This is a schematic flowchart of a wafer thinning method provided in another embodiment of this application;

[0053] Figure 10 This is a block diagram of the portable probe in-situ detection system provided in this embodiment;

[0054] Figure 11 This is a flowchart of obtaining the grinding wheel health status and adjusting the process based on the grinding wheel health status provided in the embodiments of this application;

[0055] Figure 12 This is a schematic diagram of the process for obtaining the porosity of a grinding wheel provided in an embodiment of this application;

[0056] Figure 13 This is a schematic diagram of grayscale processing provided in an embodiment of this application;

[0057] Figure 14 This is a schematic diagram of the structure of a wafer thinning device provided in an embodiment of this application;

[0058] Figure 15 This is a schematic diagram of the structure of the index acquisition unit provided in an embodiment of this application;

[0059] Figure 16 This is a schematic diagram of the structure of the process control unit provided in the embodiments of this application;

[0060] Figure 17 This is a schematic diagram of the structure of a wafer thinning apparatus provided in another embodiment of this application;

[0061] Figure 18 This is a cross-sectional view of a wafer thinning apparatus provided in another embodiment of this application;

[0062] Figure 19 This is a schematic block diagram of the system configuration of the electronic device provided in the embodiments of this application. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the embodiments of this application will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments and descriptions of this application are used to explain this application, but are not intended to limit this application.

[0064] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0065] Furthermore, it should be noted that the use of terms such as "first" and "second" to define related concepts is merely for the purpose of distinguishing the corresponding concepts. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, the terminology used in this application is selected from commonly known and used terms, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0066] like Figure 1 The diagram shown is a schematic flowchart of a wafer thinning method provided in an embodiment of this application. The method includes the following steps:

[0067] Step S101: Use schlieren to obtain the actual characteristic parameters of the bow-shaped wave of the coolant during the wafer thinning process.

[0068] During wafer grinding, the grinding wheel rotates continuously. Coolant is sprayed from the center of the grinding wheel and ejected as it rotates, creating bow-shaped waves. Because the grinding wheel and coolant are in contact, the state of the grinding wheel affects the temperature and shape of the coolant, both of which alter the shape of the bow-shaped waves. Therefore, this embodiment utilizes schlieren to capture these changes in bow-shaped wave shape, more specifically, to capture changes in the characteristic parameters of the bow-shaped waves, enabling in-situ real-time monitoring of the grinding wheel's state.

[0069] Step S102: Based on the actual characteristic parameters and the reference characteristic parameters under normal working conditions, obtain the heat dissipation index and wear index of the grinding wheel.

[0070] In this embodiment, the baseline characteristic parameters under normal operating conditions can be obtained through historical data analysis or through relevant experimental calibration. The baseline characteristic parameters are used to characterize the bow-shaped wave characteristics of the grinding wheel under normal conditions. The normal state of the grinding wheel indicates that the grinding wheel has good grinding ability. The change in the grinding ability of the grinding wheel is represented by the heat dissipation index and the wear index.

[0071] The heat dissipation index and the wear index are quantitative indicators obtained by comparing preset benchmark characteristic parameters with actual characteristic parameters. The heat dissipation index is used to characterize the heat exchange and heat dissipation capacity of the grinding wheel during the grinding process, while the wear index is used to characterize the removal and smoothing capacity of the grinding wheel during the grinding process.

[0072] Grinding wheels contain numerous pores, whose main functions are chip removal and heat dissipation. As grinding progresses, these pores become clogged with grinding debris, leading to a decrease in the grinding wheel's heat exchange and heat dissipation capabilities, and consequently, a reduction in grinding accuracy. Therefore, the heat dissipation index can be used to characterize the clogging status of the grinding wheel. Optionally, the composition of the heat dissipation index can be determined by the shape characteristics of the bow-shaped wave, and can also be corrected using temperature-dependent and time-dependent correction terms to reflect the influence of temperature on flow and heat conduction.

[0073] As grinding progresses, abrasive grains detach and edges wear on the grinding wheel, leading to a decrease in its ability to remove and smooth material from the back side of the wafer. This, in turn, reduces grinding efficiency and accuracy. Therefore, the wear index can characterize the surface wear of the grinding wheel. Optionally, the wear index is an indicator that quantifies the wear state based on the changing trend of bow-shaped wave-related characteristics and deviation from the baseline, focusing on reflecting the influence of grinding wheel edges, surface morphology changes, and wear progression on the bow-shaped wave.

[0074] Therefore, by comparing and analyzing the actual characteristic parameters and the reference characteristic parameters, the heat dissipation index and wear index of the grinding wheel can be obtained, thus comprehensively characterizing the grinding capability of the grinding wheel at the moment when the actual characteristic parameters are measured.

[0075] Step S103: Adjust the wafer thinning process in real time based on the heat dissipation index and wear index.

[0076] Based on the definitions of the heat dissipation index (characterizing the heat exchange and heat dissipation capacity of the grinding wheel during the grinding process) and the wear index (characterizing the removal and smoothing capacity of the grinding wheel during the grinding process) in step S102, this step dynamically adjusts the wafer thinning process using these two indices acquired in real time. Specifically, a change in the heat dissipation index may indicate that the grinding wheel is clogged, thus affecting the heat exchange and heat dissipation effect; a change in the wear index reflects the change in the overall wear state of the grinding wheel during the grinding process. Therefore, by comparing these two indices with preset thresholds, corresponding process adjustment strategies and / or grinding wheel dressing strategies can be obtained, thereby achieving precise and real-time control of the wafer thinning process.

[0077] As can be seen from the above technical solutions, the wafer thinning equipment and thinning method provided in this application use schlieren to detect the bow wave of the coolant, which can indirectly obtain the heat dissipation and wear information of the grinding wheel in real time. This allows for real-time evaluation of the grinding wheel's grinding capability to adjust the wafer thinning process in real time, ensuring the stability of the wafer processing process and improving wafer processing efficiency and the yield of the final chip.

[0078] In a preferred embodiment of this application, such as Figure 2 As shown, the step S101 above, which uses schlieren to obtain the actual characteristic parameters of the coolant bow-shaped wave during wafer thinning, may further include:

[0079] Step S1011: The bow-shaped wave of the coolant ejected during the wafer thinning process is captured using the single-mirror coaxial optical path of the schlieren device. The components of the single-mirror coaxial optical path include a light source disposed below the ejected coolant, a beam splitter on the wafer grinding chamber cover, and a schlieren camera above the beam splitter.

[0080] In this embodiment, the entire grinding process takes place inside the grinding chamber. To observe and capture the bow-shaped wave of the coolant, a transparent viewing window (such as an acrylic plate or glass plate) can be provided on the cover plate above the grinding chamber. Next, a single-mirror coaxial optical path system is constructed. The key components of this system include: a light source: installed at the bottom of the grinding chamber, below the coolant; a beam splitter: positioned above the transparent cover plate; and a schlieren camera: fixed at the center of several workstations by a support rod, located above the beam splitter, capable of capturing images in real time and transmitting them to a PC for processing.

[0081] With this arrangement, light emitted from the light source passes through the bow-shaped wave of the coolant, is reflected by a beam splitter to the schlieren camera above, and thus clearly captures the image of the bow-shaped wave generated by changes in coolant density and temperature. This design enables online monitoring of bow-shaped waves with minimal modifications to existing equipment.

[0082] Step S1012: Process the bow-shaped wave to extract the actual characteristic parameters of the measured working condition.

[0083] After the schlieren camera captures continuous bow-shaped wave images, the software on the PC processes these images to extract quantized actual feature parameters.

[0084] In another preferred embodiment of this application, the above-mentioned actual characteristic parameters and reference characteristic parameters include: crest angle, amplitude and wavefront curvature.

[0085] In this embodiment, the crest angle, wave amplitude, and wavefront curvature are selected as characteristic parameters. Their physical meanings are the degree of fluid resistance, energy transfer efficiency, and velocity gradient, respectively. The crest angle and wavefront curvature directly correspond to the curvature terms in Kelvin's ship wave theory and the Navier-Stokes equations of fluid dynamics. Therefore, they have a direct physical relationship with the fundamental physical laws of fluid dynamics, making the subsequent related indices obtained based on these parameters more reliable and instructive. Figure 3 The diagram shows the positions of these three parameters on the bow wave waveform. Figure 3 It is evident that there is a significant difference between the bow-shaped wave under normal operating conditions and the measured operating conditions, and the three parameters also show a corresponding significant difference.

[0086] In this embodiment, the following parameters can be obtained through initial calibration: reference crest angle θ0, reference amplitude A0, and reference wavefront curvature k0 under normal operating conditions. The following parameters can be obtained through real-time monitoring: actual crest angle θ, actual amplitude A0, and actual wavefront curvature k0 under the measured operating conditions.

[0087] In another preferred embodiment of this application, such as Figure 4 As shown, in step S102 above, obtaining the heat dissipation index and wear index of the grinding wheel based on actual characteristic parameters and reference characteristic parameters under normal working conditions may further include:

[0088] Step S1021: Based on the peak angle and amplitude in the reference characteristic parameters and the actual characteristic parameters, obtain the heat dissipation index of the grinding wheel.

[0089] The heat dissipation performance of a grinding wheel is mainly related to the penetration and heat exchange efficiency of the coolant. The amplitude reflects the change in the coolant's kinetic energy and density, and is positively correlated with heat exchange efficiency: a decrease in amplitude indicates insufficient coolant penetration and reduced heat dissipation. The angle between the wave crests reflects the degree of fluid obstruction: an increase in the angle indicates wear at the grinding wheel edge, leading to obstructed coolant flow and reduced heat dissipation; a decrease in the angle indicates blockage by abrasive particles, which also results in reduced heat dissipation.

[0090] Therefore, based on the relationship between the peak angle and amplitude and heat dissipation, and combined with heat exchange and coolant dynamics information, this embodiment initially constructs the basic dimensions of the heat dissipation index, that is, defines the heat dissipation index (CI) as the following formula (1):

[0091] (1)

[0092] Among them, the first item The first term is the basic term, characterizing the degree to which the measured amplitude deviates from the reference amplitude; the second term... This is a flow resistance adjustment term to remove interference from flow resistance; the third term. This is a secondary penalty term to remove the interference of outliers on the heat dissipation index; α, β, and γ are weighting coefficients, with values ​​of α = 0.7, β = 0.2, and γ = 0.1; A is the reference amplitude under the measured operating condition; A0 is the reference amplitude under the normal operating condition; θ is the actual peak angle under the measured operating condition; θ0 is the reference peak angle under the normal operating condition; θ max The angle between the maximum reference wave crests.

[0093] Preferably, in this embodiment, the heat dissipation index of equation (1) is also corrected by temperature compensation factor and / or time decay factor to obtain equations (2) and (3) respectively.

[0094] (2)

[0095] (3)

[0096] in: e is the temperature compensation factor. -λt The time decay factor is T, where T is the real-time coolant temperature; T0 is the reference temperature; T c It is the critical temperature; k=0.3 is the temperature sensitivity coefficient; λ=0.001h -1 , is the aging coefficient; t is the cumulative usage time of the grinding wheel, in hours.

[0097] Finally, CI'' is the heat dissipation index of the grinding wheel in this step.

[0098] This embodiment introduces a temperature compensation factor to offset the effect of ambient temperature on the thermal coupling between the coolant and the grinding wheel; and further introduces a time decay factor to eliminate the interference of the cumulative effect of wear / heat accumulation over time on the heat dissipation index.

[0099] Step S1022: Based on the crest angle and wavefront curvature in the reference characteristic parameters and actual characteristic parameters, obtain the wear index of the grinding wheel.

[0100] The wear condition of a grinding wheel is mainly related to its shape. In this embodiment, it can be quantified using the crest angle and wavefront curvature of the coolant bow-shaped wave. An increase in the crest angle (positive deviation) usually indicates edge wear (positive weights are used, negative deviations do not contribute). The absolute value of the change in wavefront curvature reflects surface unevenness (such as uneven wear), while the rate of change of the crest angle reflects the trend of accelerated wear (a sudden increase indicates abnormal wear).

[0101] Therefore, in this embodiment, the Wear State Index (WSI) is defined as follows (4):

[0102] (4)

[0103] Where μ1, μ2, and μ3 are weighting coefficients with values ​​of μ1=0.6, μ2=0.3, and μ3=0.1; θ0 is the reference peak angle under normal operating conditions, and θ is the actual peak angle under measured operating conditions; k0 is the wavefront curvature under normal operating conditions, and k is the wavefront curvature under measured operating conditions. It reflects steady-state wear and is a nonlinear response, which can capture the long-term, gradual wear of the grinding wheel; It reflects changes in morphology and belongs to two-way deviation, both of which reflect abnormalities. It can sensitively reflect the unevenness of the grinding wheel surface caused by uneven wear and other reasons. It reflects dynamic changes, and the rate of change of the peak angle only takes the direction of increase, which can promptly detect the trend of accelerated wear or sudden abnormal wear.

[0104] The wear index in this embodiment does not rely on a single parameter, but integrates steady-state wear, morphological changes, and dynamic changes. This multi-dimensional comprehensive evaluation overcomes the limitations of a single index, making the characterization of the wear state of the grinding wheel more comprehensive and accurate.

[0105] The aforementioned calculations of the heat dissipation index and wear index used reference characteristic parameters and actual characteristic parameters. The methods for obtaining these two parameters are explained below:

[0106] First, obtain the reference characteristic parameters under normal operating conditions, namely the reference peak angle θ0, the reference amplitude A0, and the reference wavefront curvature k0, such as... Figure 5 As shown, it may include the following steps:

[0107] Step S501: Prepare the standard test conditions for the coolant, setting the ambient temperature to 23±1℃, the grinding wheel speed to 3000±50r / min, the flow rate to 15 L / min, the wiper frequency to 1 time / 5 seconds, and turn on the high-speed camera.

[0108] Step S502: Set the image acquisition time interval and total acquisition duration, and acquire 30 sets of image data distributed at intervals within the total acquisition duration. Each set of data contains 100 bow wave images, and each image has timestamp information;

[0109] Step S503: Open the PC software, remove photos that are obscured by windshield wipers or other debris, and keep 10 clear bow wave photos for each group;

[0110] Step S504: Extract the crest angle, amplitude, and wavefront curvature data of the bow wave from 10 images in each group, calculate the weighted average of each parameter, and input the weighted average feature value into the numerical analysis module to construct a "health database" for each grinding wheel under normal working conditions through machine learning.

[0111] The aforementioned "health database" stores the reference wave crest angle θ0, reference wave amplitude A0, and reference wavefront curvature k0 corresponding to each grinding wheel.

[0112] Secondly, the actual characteristic parameters under the measured working conditions are obtained, namely the actual crest angle θ, the actual wave amplitude A, and the actual wavefront curvature k. During the online monitoring process, the crest angle, wave amplitude, and wavefront curvature data of the bow wave in 10 images are extracted, and their weighted average is calculated as the actual crest angle θ, actual wave amplitude A, and actual wavefront curvature k, so that they can be compared and analyzed with the benchmark values ​​in the "health database" of the grinding wheel under normal working conditions.

[0113] Specifically, the process for obtaining the actual characteristic parameters under measured conditions can be found in [reference needed]. Figure 6 As shown:

[0114] Step S601: Extract the crest angle θ, amplitude A, and wavefront curvature k of the bow wave from 10 images, calculate the weighted average value, and compare it with the benchmark value in the "health database" of the grinding wheel under normal working conditions.

[0115] Step S602: Extract θ and A for calculating the heat dissipation index CI; add temperature compensation factor to obtain the actual heat dissipation index CI value C and time compensation factor C.

[0116] Step S603: Extract θ and k for use in calculating the wear index (WSI) value.

[0117] Step S604: Determine the grinding wheel's heat dissipation state and wear state based on the intervals where the CI value and WSI value are located, substitute them into the grinding wheel life calculation formula, and combine with the offline detection data to evaluate the current health and remaining life of the grinding wheel.

[0118] As can be seen from the above, in this embodiment, physical quantities such as the wave crest angle, wave amplitude, and wavefront curvature are combined to form a quantitative index that can cover two dimensions of heat dissipation and wear, which can accurately represent the influence of the temperature change and shape change of the coolant on the bow wave waveform, thus providing precise quantitative guidance for evaluating the grinding wheel life and dynamically and real-time controlling the grinding process. In addition, in this embodiment, by adjusting the CI with the temperature compensation factor and time decay factor, considering the environmental temperature fluctuation and the time effect of wear / heat accumulation, the heat dissipation index has a more consistent scale and comparability under different working conditions.

[0119] In another preferred embodiment of the present application, as Figure 7 shown, the further adjustment of the wafer thinning process based on the heat dissipation index and wear index in the above step S103 may include:

[0120] Step S1031: Compare the heat dissipation index with multiple preset heat dissipation state thresholds, and obtain the corresponding process adjustment strategy according to the comparison result to perform process adjustment.

[0121] Step S1032: Compare the wear index with multiple preset wear state thresholds, and obtain the corresponding grinding wheel dressing strategy according to the comparison result to perform grinding wheel dressing and / or obtain the corresponding process adjustment strategy to perform process adjustment.

[0122] As Figure 8 shown is the flowchart of the online monitoring numerical determination logic provided by the embodiment of the present application, which can give the grinding wheel heat dissipation state, wear state, and subsequent action suggestions based on the interval determination of the currently collected bow wave characteristic parameters (θ, A, k) and the heat dissipation index CI'' and wear index WSI.

[0123] The determination of the heat dissipation state (CI'') is as follows:

[0124] CI'' ≤ 0.5: It means that the wave amplitude drops suddenly and the wave crest angle expands, and emergency shutdown for maintenance is required.

[0125] 0.5 < CI'' ≤ 0.7: It means that the local wave amplitude drops, and the spindle feed speed needs to be reduced and the cooling water flow rate needs to be increased.

[0126] 0.7 < CI'' < 0.85: It means that there is slight waveform distortion, and the cooling water flow rate needs to be increased.

[0127] CI''≥ 0.85: This indicates a stable bow wave that can maintain its current parameters without intervention.

[0128] Wear condition assessment (WSI) is as follows:

[0129] WSI > 0.5: Severe wear, requiring emergency intervention; stop the machine and replace the grinding wheel.

[0130] 0.3 < WSI ≤ 0.5: Moderate wear, requires monitoring and possible adjustment of process parameters or initiation of grinding wheel dressing maintenance (using a dressing wheel and grinding wheel at a certain speed ratio for grinding).

[0131] 0.1 < WSI ≤ 0.3: Slight wear. Maintain current operation and observe the wear trend.

[0132] WSI ≤ 0.1: Normal wear, no manual intervention required.

[0133] This embodiment couples the three parameters of online monitoring into a unified judgment framework, forming a comprehensive assessment and action decision path for grinding wheel heat dissipation and wear. Through clear interval division, rapid, intuitive, and executable maintenance and process control strategies can be achieved.

[0134] All the above embodiments use online detection to assess the condition of the grinding wheel. However, this method requires the light source, wipers, and schlieren camera to remain constantly operational, leading to increased power consumption. Furthermore, these components are consumables requiring regular maintenance and replacement. Online detection necessitates real-time data acquisition and processing, which consumes excessive system resources, further contributing to high detection costs. On the other hand, while schlieren can detect the overall condition of the grinding wheel, it is ultimately an "indirect" detection method and is not comprehensive enough in assessing the remaining service life of the grinding wheel.

[0135] Therefore, in another preferred embodiment of this application, a rapid local in-situ detection method is introduced and combined with online detection to overcome the above-mentioned defects. For example... Figure 9 As shown, before obtaining the actual characteristic parameters of the coolant bow-shaped wave during wafer thinning using the schlieren method, the method of this application further includes:

[0136] Step S104: Perform non-destructive in-situ testing on the grinding wheel to obtain its porosity.

[0137] This step aims to detect the porosity of the grinding wheel in a non-destructive manner. "In-situ detection" means that the detection is performed without disassembling the grinding wheel, and "non-destructive" means that this embodiment does not damage the grinding wheel. To achieve "non-destructive in-situ detection," this embodiment uses a portable probe equipped with multi-physics field detection such as light / sound waves to replace traditional industrial CT (industrial computed tomography) detection. It should also be noted that the "non-destructive in-situ detection" in this embodiment is also "online non-destructive in-situ detection," meaning that the detection does not require machine downtime but can be achieved by utilizing the grinding gap of the grinding wheel (for example, the gap between finishing grinding one wafer and switching to the next wafer).

[0138] Traditional industrial CT inspection is a high-cost, highly invasive, and time-consuming inspection method. It usually requires disassembling, positioning, and placing the object to be inspected inside the CT equipment for multi-angle X-ray scanning to obtain information such as the three-dimensional density distribution inside the material and reconstruct the internal pore structure.

[0139] This implementation uses a portable probe to replace traditional industrial CT inspection, enabling non-destructive in-situ testing of the grinding wheel without disassembly, ensuring the structural integrity and normal use of the grinding wheel. Figure 10 The diagram shows the modules of the portable probe in-situ detection system provided in this embodiment. The image acquisition module includes a portable probe, a miniature camera, etc.; the data conversion module includes a multi-physics sensor chip for light waves (infrared / ultraviolet / X-rays, etc.) and sound waves (infrared / ultrasound, etc.), transmitting and receiving devices, and circuit components; the data output module includes an image display device, result analysis software, etc.; and finally, the comprehensive analysis module outputs the porosity of the grinding wheel.

[0140] Step S105: Determine whether online monitoring is required based on porosity. If monitoring is required, proceed to step S101 and use schlieren to obtain the actual characteristic parameters of the coolant bow wave during wafer thinning.

[0141] If the porosity meets the requirements after the non-destructive in-situ inspection in step S104, it indicates that the grinding wheel is in good condition. At this time, there is no need to adjust it or evaluate its remaining service life. It can be allowed to work normally, which will not affect production and can also reduce the consumption of computing resources.

[0142] If the porosity does not meet the requirements, since non-destructive in-situ testing is only a single local test, it cannot comprehensively evaluate the overall condition, global distribution and dynamic changes of the grinding wheel. Therefore, online monitoring (i.e. the scheme described in steps S101-S103 above) needs to be introduced to obtain continuous and real-time status information, and corresponding process adjustments can be made based on the online monitoring results.

[0143] In this embodiment, although the portable probe can only detect a local area of ​​the grinding wheel, such as 1-2 grinding teeth, and optical or acoustic solutions cannot achieve the accuracy of traditional industrial CT inspection, in-situ local detection, as a rapid and low-cost initial screening method, can avoid activating the high-power and costly online monitoring system when the grinding wheel is in good condition. Online monitoring is only activated when in-situ detection detects abnormal porosity (e.g., below 30% or above 60%), indicating a potential problem with the grinding wheel. This avoids the continuous operation of online monitoring equipment (such as light sources, cameras, wipers, etc.), saving power and extending the lifespan of these consumable components, thereby reducing the overall inspection cost. In addition, although in-situ detection is fast, it is essentially a local and static detection, unable to capture the dynamic changes of the grinding wheel during the actual grinding process. Online monitoring (analyzing bow waves using schlieren) can provide continuous, real-time dynamic data, reflecting the heat dissipation and wear status of the grinding wheel. By combining these two approaches, the macroscopic structure (porosity) of the grinding wheel is first directly assessed through in-situ local testing. Then, online monitoring is initiated when necessary to conduct a detailed analysis of dynamic performance (heat dissipation, wear). This combination of static and dynamic approaches allows the assessment of the grinding wheel's condition to move beyond local or single-dimensional evaluations, achieving a comprehensive assessment of the entire surface of the grinding wheel. This significantly improves the comprehensiveness and accuracy of the assessment results.

[0144] In another preferred embodiment of this application, such as Figure 11 As shown, the method of this application further includes:

[0145] Step S1101: Based on porosity, heat dissipation index and wear index, obtain the corresponding in-situ detection health, heat dissipation health and wear health respectively.

[0146] The in-situ detection health status is denoted as H1, and the heat dissipation health status is denoted as H. c Wear and tear health is represented by H. w Then H1(φ) = 0.5{φ<0.3} + 1{0.3≤φ≤0.6} + 0{φ>0.6}, meaning the relationship between in-situ health and porosity φ can be expressed as a piecewise function; H c =CI'',H c Consistent with CI'', an increase in the heat dissipation index indicates a positive correlation with improved heat dissipation health; H w =e -2WSI H w The higher the WSI, the more severe the wear. H w The smaller the value, the more accurately the negative exponential function reflects changes in wear and tear health.

[0147] These health indicators were obtained from in-situ nondestructive testing and online monitoring, respectively. They are multimodal data characterizing the health of grinding wheels, thus ensuring that the fused grinding wheel health can be used to objectively and accurately evaluate the condition of the grinding wheel.

[0148] Step S1102: Based on in-situ detection of health status (H1) and heat dissipation health status (H2), c ) and wear and tear health (H) w Obtain the health status of the grinding wheel.

[0149] Specifically, in this embodiment, the health of the grinding wheel is obtained through the following formula (5):

[0150] LI = 0.2H1 + 0.4H c +0.4H w (5)

[0151] Where H1 represents the local health level, H c and H w This represents the overall health status, therefore for H c and H w Give it a higher weight than H1.

[0152] Step S1103: Determine whether grinding wheel dressing or replacement is necessary based on the condition of the grinding wheel.

[0153] In this step, the entire lifecycle state of the grinding wheel can be mapped to different health ranges, and corresponding operation instructions are preset for each range. Then, the real-time calculated "grinding wheel health" is compared with these preset thresholds. If the health is high (e.g., above a certain safety threshold): it indicates that the overall condition of the grinding wheel is good, and both its structure (porosity) and dynamic performance (heat dissipation, wear) are within acceptable ranges. At this time, the system determines that no intervention is needed, and the grinding wheel can continue to work normally. If the health is moderate (e.g., dropped to a certain range): it may mean that the grinding wheel has experienced mild or moderate performance degradation. The system may suggest "dressing" measures, such as using a dressing wheel to grind against the grinding wheel, to restore the sharpness and cleanliness of the grinding wheel surface, thereby improving its grinding performance. If the health is too low (e.g., below a certain severity threshold): this indicates that the grinding wheel has serious structural damage (such as severely abnormal porosity), performance problems (such as severely poor heat dissipation), or excessive wear, which cannot be restored by dressing. At this point, the system will issue a "replace" command, requiring the machine to stop and a new grinding wheel to be installed, in order to avoid irreversible damage to the wafer processing and to ensure product quality and production safety.

[0154] In another preferred embodiment of this application, the method may further include: obtaining an assessment value of the remaining service life of the grinding wheel based on the grinding wheel health status using a grinding wheel life assessment model, wherein the grinding wheel life assessment model is:

[0155] (6)

[0156] Among them, T remain T represents the remaining useful life assessment value. total =500h, e -λt λ is the time decay factor, where t is the actual machine time and λ is the decay coefficient.

[0157] In this embodiment, the weighted geometric mean is chosen instead of the arithmetic mean because when an indicator drops sharply, the geometric mean provides an early warning about 17% faster than the arithmetic mean.

[0158] As described above, the multi-modal fusion decision-making mechanism is achieved by employing the step-by-step process of steps S1001-S1003 (i.e., calculating the corresponding health status from porosity, heat dissipation index, and wear index separately, then fusing them to obtain the overall health status of the grinding wheel, and finally using the life assessment model to obtain the remaining service life assessment value). By converting the data from in-situ detection (based on porosity) and online monitoring (based on heat dissipation and wear index) into health status indicators step by step and fusing them into an overall health status, the limitations of single detection technology are overcome, significantly improving the accuracy and comprehensiveness of grinding wheel condition assessment, and supporting precise mapping of structural damage, heat dissipation problems, and wear processes. Based on the calculated health status and remaining service life assessment value, this application can promptly trigger early warnings (such as adjusting process parameters or dressing the grinding wheel when the health status decreases), reducing unnecessary downtime, maximizing grinding wheel utilization, reducing detection costs, and ensuring the stability of the wafer thinning process.

[0159] In another preferred embodiment of this application, such as Figure 12 As shown, the non-destructive in-situ testing of the grinding wheel in this step to obtain the porosity of the grinding wheel may further include:

[0160] Step S1201: Measure the propagation and scattering characteristics of light waves in the grinding wheel to determine the first porosity of the grinding wheel.

[0161] In this step, the first porosity information can be obtained through existing optical wave detection.

[0162] Step S1202: Measure the propagation and scattering characteristics of sound waves in the grinding wheel to determine the second porosity of the grinding wheel.

[0163] In this step, the second porosity information can be detected using existing acoustic waves.

[0164] To obtain accurate information on the first and second porosity, preprocessing steps such as noise reduction and grayscale processing can be performed on the acquired images. Figure 13The image shown is a schematic diagram of grayscale processing of the measured photos obtained from optical wave detection and acoustic wave detection.

[0165] Step S1203: Weighted fusion of the first porosity and the second porosity to obtain the third porosity as the porosity of the grinding wheel.

[0166] The first porosity obtained in step S1201 is denoted as φ1, and the second porosity obtained in step S1202 is denoted as φ2. The third porosity φ can be obtained in this step by the following formula (7):

[0167] φ = 50% φ1 + 50% φ2 (7)

[0168] When φ < 30%, it indicates severe blockage of the grinding wheel's pores; when 30% ≤ φ When φ is ≤60%, it indicates that the grinding wheel is in normal condition; when φ>60%, it indicates that the grinding wheel's bending strength and sharpness are reduced.

[0169] Accordingly, the step S105 above, which determines whether online monitoring is required based on porosity, includes: determining whether the third porosity is within a preset range; if not, online monitoring is required.

[0170] Therefore, when 30% ≤ φ When φ is ≤60%, the grinding wheel is in good condition and no adjustment or assessment of its remaining service life is required; it can be left to operate normally. However, when φ <30% or φ >60%, online monitoring is necessary. The online monitoring results should be combined with the in-situ testing results for analysis, and the remaining service life assessment and maintenance strategy should be updated accordingly.

[0171] As described above, the first porosity φ1 (optical wave detection) and the second porosity φ2 (acoustic wave detection) are sensitive to different aspects of the grinding wheel's pore structure. A simple fusion can be achieved using the formula φ = 50% φ1 + 50% φ2, thereby mitigating the noise and limitations of a single mode and improving the robustness of judging the degree of pore blockage and the condition of the grinding wheel. Because relying solely on a single mode is easily affected by environmental factors, material heterogeneity, and detection errors, the fused mode provides a more reliable judgment when φ falls outside the normal range, reducing the risk of misjudging a good grinding wheel as requiring maintenance. Furthermore, this embodiment only activates online monitoring when φ crosses a threshold, avoiding the overhead of continuous online monitoring under normal conditions, achieving a balance between cost and monitoring requirements.

[0172] like Figure 14 The diagram shown is a schematic representation of a wafer thinning apparatus provided in an embodiment of this application, comprising:

[0173] Schlieren apparatus 1410 is used to obtain the actual characteristic parameters of the bow-shaped wave of coolant during wafer thinning using the schlieren method.

[0174] The index acquisition unit 1420 is used to obtain the heat dissipation index and wear index of the grinding wheel based on the actual characteristic parameters and the reference characteristic parameters under normal working conditions.

[0175] The process control unit 1430 is used to control the adjustment of the wafer thinning process in real time based on the thermal performance index and the wear index.

[0176] In a preferred embodiment of this application, the schlieren device 1410 is specifically used to: capture the bow-shaped wave of the coolant ejected during the wafer thinning process using the single-mirror coaxial optical path of the schlieren device, wherein the components of the single-mirror coaxial optical path include a light source disposed below the ejected coolant, a beam splitter on the wafer grinding chamber cover, and a schlieren camera above the beam splitter; and process the bow-shaped wave to extract actual feature parameters.

[0177] In a preferred embodiment of this application, the above-mentioned actual characteristic parameters and reference characteristic parameters include: wave crest angle, wave amplitude, and wavefront curvature.

[0178] In a preferred embodiment of this application, such as Figure 15 As shown, the index acquisition unit 1420 includes:

[0179] The heat dissipation index acquisition module 1421 is used to obtain the heat dissipation index of the grinding wheel by adjusting the peak angle and amplitude in the reference characteristic parameters and actual characteristic parameters through temperature compensation factor and / or time decay factor.

[0180] The wear index acquisition module 1422 is used to obtain the wear index of the grinding wheel based on the peak angle and wavefront curvature in the reference characteristic parameters and actual characteristic parameters.

[0181] In a preferred embodiment of this application, such as Figure 16 As shown, the process control unit 1430 includes:

[0182] The first adjustment module 1431 is used to compare the heat dissipation index with multiple preset heat dissipation state thresholds, and obtain the corresponding process adjustment strategy based on the comparison results to perform process adjustment.

[0183] The second adjustment module 1432 is used to compare the wear index with multiple preset wear state thresholds, and obtain the corresponding grinding wheel dressing strategy based on the comparison results to perform grinding wheel dressing and / or process adjustment.

[0184] In a preferred embodiment of this application, the device further includes:

[0185] The detection unit is used to perform non-destructive in-situ testing on the grinding wheel to obtain its porosity.

[0186] The judgment unit is used to determine whether online monitoring is required based on porosity. If monitoring is required, the actual characteristic parameters of the coolant bow wave during wafer thinning are obtained using the schlieren method.

[0187] In a preferred embodiment of this application, the device further includes:

[0188] The first health status acquisition unit is used to obtain the corresponding in-situ detection health status, heat dissipation health status and wear health status based on porosity, heat dissipation index and wear index, respectively.

[0189] The second health assessment unit is used to acquire health status based on in-situ detection (H1) and heat dissipation health status (H). c ) and wear and tear health (H) w To obtain the grinding wheel health (LI): LI = 0.2H1 + 0.4H c +0.4H w ;

[0190] The grinding wheel adjustment unit is used to determine whether grinding wheel dressing or replacement is needed based on the condition of the grinding wheel.

[0191] In a preferred embodiment of this application, the device further includes:

[0192] The life assessment unit is used to obtain the remaining service life assessment value of the grinding wheel based on the grinding wheel health status and using the grinding wheel life assessment model; the grinding wheel life assessment model is as follows:

[0193] ;

[0194] Among them, T remain T represents the remaining useful life assessment value. total =500h, e -λt λ is the time decay factor, where t is the actual machine time and λ is the decay coefficient.

[0195] In a preferred embodiment of this application, the detection unit includes:

[0196] The optical wave detection module is used to measure the propagation and scattering characteristics of light waves in the grinding wheel in order to determine the first porosity of the grinding wheel.

[0197] The acoustic wave detection module is used to measure the propagation and scattering characteristics of acoustic waves in the grinding wheel in order to determine the secondary porosity of the grinding wheel.

[0198] The weighted fusion module is used to weight and fuse the first porosity and the second porosity to obtain the third porosity as the porosity of the grinding wheel.

[0199] In a preferred embodiment of this application, the aforementioned judgment unit is specifically used to: determine whether the third porosity is within a preset range; if not, online monitoring is required.

[0200] As can be seen from the above technical solution, the wafer thinning equipment provided in this application uses schlieren to detect the bow wave of the coolant, which can indirectly obtain the heat dissipation and wear information of the grinding wheel in real time. This allows for real-time evaluation of the grinding capability and health status of the grinding wheel, enabling real-time adjustment of the wafer thinning process, ensuring the stability of the wafer processing process, improving wafer processing efficiency and the yield of the final chip.

[0201] like Figure 17 The diagram shown is a schematic representation of a wafer thinning apparatus according to another embodiment of this application, comprising: an adsorption platform 1, a grinding device 2, a light source 3, and a schlieren camera 4. Wherein:

[0202] The adsorption platform 1 is a worktable that supports and fixes the wafer. During the wafer thinning process, it can firmly fix the wafer on the platform through vacuum adsorption and other methods, and drive the wafer to rotate at high speed to cooperate with the grinding device 2 above for uniform grinding. Figure 17 As can be seen, a wafer thinning device can have multiple adsorption platforms 1, for example... Figure 17 There are 3 in the middle.

[0203] The grinding device 2 is the core module that performs the actual thinning work. It is positioned directly above the adsorption platform 1, and its lower part has a grinding wheel for grinding the wafer. During operation, the grinding device 2 descends, bringing the rotating grinding wheel into contact with the rotating wafer on the adsorption platform. Through physical grinding, the wafer material is removed, achieving the purpose of thinning.

[0204] Light source 3, located below one side of the adsorption platform 1, is a component for implementing schlieren imaging. It is typically a point light source, installed at the bottom of the grinding station, below one side of the adsorption platform. Its function is to provide a beam of light that passes through the bow-shaped wave of the coolant. The light is deflected due to changes in flow density and temperature, which is the basis of schlieren imaging.

[0205] The schlieren camera 4, another key component in implementing the schlieren method, is used to capture the bow-shaped wave of the coolant. It is located above one side of the adsorption platform 1, directly opposite the light source 3 below, to receive the light rays passing through the bow-shaped wave of the coolant. This camera (typically a high-speed camera) captures the schlieren image formed by the refraction of light in real time, i.e., the shape of the coolant bow-shaped wave. These images are then transmitted to a processing system to analyze characteristic parameters such as the wave crest angle and amplitude, thereby calculating the heat dissipation index and wear index of the grinding wheel, enabling real-time control of the thinning process.

[0206] In a preferred embodiment of this application, the wafer thinning equipment further includes a turntable 5, which is used to rotate and drive the adsorption platform 1 to change positions. The turntable 5 has a window for placing the adsorption platform 1, and the upper surface of the adsorption platform 1 is higher than the window plane. The turntable 5 can be made of metal such as stainless steel. Since the wafer thinning equipment has multiple adsorption platforms (stations), the station can be switched by rotating the turntable 5.

[0207] In another preferred embodiment of this application, such as Figure 18 As shown, the aforementioned wafer thinning equipment also includes a turntable cover 6 (the turntable cover 6 is in...) Figure 17 (Not shown in the diagram), it is placed on top of the turntable 5, thus forming a grinding chamber between the turntable 6 and the turntable 5. A viewing window 7 is provided on the top cover plate of the turntable cover 6, and the viewing window 7 is positioned directly opposite the light source 3 below. In this embodiment, the viewing window can be made of glass or transparent glass, which allows the light emitted by the light source 3 to pass through the bow-shaped wave and reach the schlieren camera 4.

[0208] In another preferred embodiment of this application, the wafer thinning apparatus further includes a wiper 8, which is disposed below the viewing window 7 and connected at one end to the side wall of the turntable cover 6, for removing coolant from the viewing window 7. Since coolant may adhere to the viewing window 7 after being ejected by the rotating grinding wheel during wafer thinning, thus affecting the schlieren imaging results, this embodiment uses a wiper 8 to periodically or as needed remove the coolant from the viewing window 7, thereby improving the detection effect of the schlieren imaging method.

[0209] In another preferred embodiment of this application, the wafer thinning apparatus further includes a support rod 9, one end of which is connected to the center of the turntable 5, and the other end is connected to the schlieren camera 4 for fixing the schlieren camera 4. Figure 17 and 18 As can be seen, the support rod 9 is an L-shaped support rod. Although it is connected to the center of the turntable 5, it does not rotate with the turntable 5. This can be achieved by separating its connecting part from the turntable 5 during rotation (for example, the connecting part at the center of the turntable 5 is separate from the turntable 5 body). The connection between the support rod 9 and the turntable 5 is detachable, for example, through a threaded connection. Its connection with the schlieren camera 4 is also detachable, for example, through a snap-fit ​​connection.

[0210] In another preferred embodiment of this application, the wafer thinning device further includes a beam splitter 10, which is disposed above the viewing window 7 and between the light source 3 and the schlieren camera 4. It can reflect the light from the point light source 3 to the schlieren camera 4, thereby forming a compact coaxial optical system.

[0211] With the above arrangement, the actual characteristic parameters of the coolant bow-shaped wave during grinding can be obtained with minimal modification to existing equipment.

[0212] As can be seen from the above technical solution, the wafer thinning equipment provided in this application uses schlieren to detect the bow wave of the coolant, which can indirectly obtain the heat dissipation and wear information of the grinding wheel in real time. This allows for real-time evaluation of the grinding capability and health status of the grinding wheel, enabling real-time adjustment of the wafer thinning process, ensuring the stability of the wafer processing process, and improving wafer processing efficiency and the yield of the final chip.

[0213] This application also provides a wafer thinning apparatus, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the wafer thinning method described above.

[0214] This application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of the wafer thinning method described above.

[0215] This application also provides a computer-readable storage medium storing a computer program that performs the above-described wafer thinning method.

[0216] like Figure 19 As shown, the electronic device 600 may also include: a communication module 110, an input unit 120, an audio processor 130, a display 160, and a power supply 170. It is worth noting that the electronic device 600 does not necessarily need to include these components. Figure 19 All components shown; in addition, the electronic device 600 may also include Figure 19 For components not shown, please refer to existing technology.

[0217] like Figure 19 As shown, the central processing unit 100, sometimes also referred to as a controller or operating control, may include a microprocessor or other processor device and / or logic device. The central processing unit 100 receives inputs and controls the operation of various components of the electronic device 600.

[0218] The memory 140 may be, for example, one or more of a cache, flash memory, hard drive, removable media, volatile memory, non-volatile memory, or other suitable devices. It may store the aforementioned failure-related information, and also store a program for executing that information. The central processing unit 100 may execute the program stored in the memory 140 to perform information storage or processing, etc.

[0219] Input unit 120 provides input to central processing unit 100. Input unit 120 may be, for example, a keypad or touch input device. Power supply 170 provides power to electronic device 600. Display 160 displays images and text. Display may be, for example, an LCD display, but is not limited thereto.

[0220] The memory 140 can be a solid-state memory, such as a read-only memory (ROM), random access memory (RAM), a SIM card, etc. It can also be a memory that retains information even when power is off, can be selectively erased, and contains more data; examples of this type of memory are sometimes referred to as EPROMs. The memory 140 can also be some other type of device. The memory 140 includes a buffer memory 141 (sometimes referred to as a buffer). The memory 140 may include an application / function storage unit 142 for storing application programs and function programs or processes for executing the operation of the electronic device 600 via the central processing unit 100.

[0221] The memory 140 may also include a data storage unit 143 for storing data, such as contacts, digital data, pictures, sounds, and / or any other data used by the electronic device. The driver storage unit 144 of the memory 140 may include various drivers for the electronic device for communication functions and / or for performing other functions of the electronic device (such as messaging applications, address book applications, etc.).

[0222] The communication module 110 is a transmitter / receiver that transmits and receives signals via the antenna 111. The communication module 110 (transmitter / receiver) is coupled to the central processing unit 100 to provide input signals and receive output signals, which can be the same as in a conventional mobile communication terminal.

[0223] Based on different communication technologies, multiple communication modules 110 can be configured in the same electronic device, such as cellular network modules, Bluetooth modules, and / or wireless LAN modules. The communication module 110 (transmitter / receiver) is also coupled to a speaker 131 and a microphone 132 via an audio processor 130 to provide audio output via the speaker 131 and receive audio input from the microphone 132, thereby enabling typical telecommunications functions. The audio processor 130 may include any suitable buffer, decoder, amplifier, etc. Additionally, the audio processor 130 is coupled to a central processing unit 100, enabling on-device recording via the microphone 132 and on-device playback of stored audio via the speaker 131.

[0224] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0225] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0226] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0227] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0228] This application uses specific embodiments to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A wafer thinning method, characterized in that, The method includes: The actual characteristic parameters of the bow-shaped wave of coolant during wafer thinning were obtained using the schlieren method. Based on the actual characteristic parameters and the reference characteristic parameters under normal working conditions, the heat dissipation index and wear index of the grinding wheel are obtained. The wafer thinning process is adjusted in real time based on the heat dissipation index and the wear index. The actual characteristic parameters and the reference characteristic parameters include: wave crest angle, wave amplitude, and wavefront curvature. The heat dissipation index and wear index of the grinding wheel are obtained based on the actual characteristic parameters and the reference characteristic parameters under normal operating conditions, including: Based on the peak angle and amplitude of the reference characteristic parameters and the actual characteristic parameters, and adjusted by the temperature compensation factor and / or time decay factor, the heat dissipation index of the grinding wheel is obtained. The wear index of the grinding wheel is obtained based on the crest angle and wavefront curvature in the reference characteristic parameters and the actual characteristic parameters.

2. The wafer thinning method as described in claim 1, characterized in that, The actual characteristic parameters of the coolant bow-shaped wave obtained during wafer thinning using the schlieren method include: The bow-shaped wave of coolant ejected during wafer thinning is captured using a single-mirror coaxial optical path of a schlieren device. The components of the single-mirror coaxial optical path include a light source disposed below the ejected coolant, a beam splitter on the wafer grinding chamber cover, and a schlieren camera above the beam splitter. The bow-shaped wave is processed to extract the actual feature parameters.

3. The wafer thinning method as described in claim 1, characterized in that, The real-time control of wafer thinning process adjustments based on the heat dissipation index and the wear index includes: The heat dissipation index is compared with multiple preset heat dissipation state thresholds, and the corresponding process adjustment strategy is obtained based on the comparison results to adjust the process. The wear index is compared with multiple preset wear state thresholds, and the corresponding grinding wheel dressing strategy is obtained based on the comparison results to perform grinding wheel dressing and / or process adjustment.

4. The wafer thinning method as described in claim 1, characterized in that, Before obtaining the actual characteristic parameters of the coolant bow-shaped wave during wafer thinning using the schlieren method, the method further includes: Non-destructive in-situ testing of the grinding wheel was performed to obtain its porosity. Based on the porosity, it is determined whether online monitoring is required. If monitoring is required, the actual characteristic parameters of the coolant bow wave during wafer thinning are obtained using the schlieren method.

5. The wafer thinning method as described in claim 4, characterized in that, The method further includes: Based on the porosity, the heat dissipation index, and the wear index, the corresponding in-situ detection health, heat dissipation health, and wear health are obtained respectively. Based on the in-situ detection health status H1 and heat dissipation health status H c and wear and tear health H w Gain grinding wheel health LI: LI=0.2H1+0.4H c +0.4H w ; Based on the condition of the grinding wheel, it is determined whether the grinding wheel needs to be dressed or replaced.

6. The wafer thinning method as described in claim 5, characterized in that, The method further includes: Based on the health status of the grinding wheel, the remaining service life of the grinding wheel is estimated using the grinding wheel life assessment model. The grinding wheel life assessment model is as follows: ； Among them, T remain T represents the remaining useful life assessment value. total =500h, e -λt λ is the time decay factor, where t is the actual machine time and λ is the decay coefficient.

7. The wafer thinning method as described in claim 4, characterized in that, The non-destructive in-situ testing of the grinding wheel to obtain its porosity includes: The propagation and scattering characteristics of light waves in the grinding wheel are measured to determine the first porosity of the grinding wheel; The propagation and scattering characteristics of sound waves in the grinding wheel are measured to determine the second porosity of the grinding wheel; The first porosity and the second porosity are weighted and fused to obtain a third porosity as the porosity of the grinding wheel.

8. The wafer thinning method as described in claim 7, characterized in that, The step of determining whether online monitoring is needed based on the porosity includes: Determine whether the third porosity is within a preset range. If it is not, online monitoring is required.

9. A wafer thinning apparatus, characterized in that, include: Schlieren apparatus is used to obtain the actual characteristic parameters of the bow-shaped wave of coolant during wafer thinning using the schlieren method; The index acquisition unit is used to obtain the heat dissipation index and wear index of the grinding wheel based on the actual characteristic parameters and the reference characteristic parameters under normal working conditions. A process control unit is used to control the adjustment of the wafer thinning process in real time based on the heat dissipation index and the wear index. The actual characteristic parameters and the reference characteristic parameters include: wave crest angle, wave amplitude and wave front curvature. The index acquisition unit is specifically used to obtain the heat dissipation index of the grinding wheel by adjusting the wave crest angle and wave amplitude in the reference characteristic parameters and the actual characteristic parameters through temperature compensation factor and / or time decay factor. The wear index of the grinding wheel is obtained based on the crest angle and wavefront curvature in the reference characteristic parameters and the actual characteristic parameters.

10. A wafer thinning apparatus, characterized in that, A wafer thinning method for implementing any one of claims 1-8 includes: An adsorption platform is used to support the wafer and drive its rotation. A grinding device is raised and lowered above the adsorption platform, and the lower part of the grinding device has a grinding wheel for grinding wafers; The light source is located below one side of the adsorption platform; The schlieren camera is located above one side of the adsorption platform, facing the light source, to collect the bow-shaped waves of the coolant; The coolant bow wave is used to determine the heat dissipation index and wear index of the grinding wheel, so as to control the wafer thinning process in real time.

11. The wafer thinning apparatus as described in claim 10, characterized in that, Also includes: A turntable is used to rotate and change the position of the adsorption platform. The turntable has a window for placing the adsorption platform, and the upper surface of the adsorption platform is higher than the window plane.

12. The wafer thinning apparatus as described in claim 11, characterized in that, Also includes: A turntable cover is placed on the turntable to form a grinding chamber between the turntable and the turntable. The turntable cover has a viewing window at a position corresponding to the position above the light source.

13. The wafer thinning apparatus as described in claim 12, characterized in that, Also includes: A windshield wiper, located below the viewing window, with one end connected to the side wall of the turntable cover, is used to remove coolant from the viewing window.

14. The wafer thinning apparatus as described in claim 11, characterized in that, Also includes: A support rod is connected at one end to the center of the turntable and at the other end to the schlieren camera, used to fix the schlieren camera.

15. The wafer thinning apparatus as described in claim 12, characterized in that, Also includes: A beam splitter is positioned above the viewing window, between the light source and the schlieren camera.

16. A wafer thinning apparatus, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 8.

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