Cleaning method and cleaning machine table based on silicon-glass bonding body

Abstract

The invention provides a cleaning method and a cleaning machine table based on a silicon-glass bonding body, and relates to the technical field of semiconductor device manufacturing. The silicon-glass bonding body is provided firstly, then the silicon-glass bonding body is fixed to a cleaning machine table, the first surface of a silicon wafer of the silicon-glass bonding body faces a polishing head, then the polishing head is controlled to polish the first surface of the silicon wafer, and polishing liquid is continuously supplied in the polishing process. And removing a sodion pollution layer on the surface of the silicon wafer. According to the technical scheme, a sodium ion pollution layer after silicon-glass bonding can be effectively removed by utilizing a chemical mechanical polishing cleaning method, pollution on the surface of a silicon wafer can be effectively cleaned, and normal proceeding of a subsequent process can be ensured.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device manufacturing technology, and in particular to a cleaning method and cleaning machine based on silicon-glass bonding. Background Technology

[0002] Silicon-glass bonding is a crucial packaging and structure formation technology in the manufacturing of semiconductor and MEMS devices. Anodic bonding, the most commonly used silicon-glass bonding method, requires temperatures of 200°C-400°C and voltages of 800V-1500V. During this process, alkali metal ions, particularly sodium ions, in the glass migrate towards the cathode (the silicon wafer) under the influence of an electric field, precipitating on the wafer surface and forming a contamination layer. The problems caused by this sodium ion contamination are significant. It not only interferes with the uniformity and selectivity of subsequent deep reactive ion etching processes but can also contaminate the internal flow channels of microfluidic chips, thus affecting the accuracy of biosensor results. More seriously, long-term accumulation can even lead to drift in the electrical performance of the device and reduce its overall reliability.

[0003] Existing cleaning methods mainly include RCA cleaning, HF acid cleaning, and plasma cleaning. RCA cleaning primarily uses mixed solutions of NH4OH / H2O2 / H2O and HCl / H2O2 / H2O, but its effectiveness in removing sodium ions precipitated after bonding is limited. Although HF acid can remove some surface contaminants, it damages the silicon wafer surface and is ineffective against deep sodium ions. Plasma cleaning is mainly used for pre-bonding treatment, and its effectiveness in addressing sodium ion precipitation after bonding is also poor. Summary of the Invention

[0004] One objective of the first aspect of this invention is to provide a cleaning method based on silicon-glass bonding, which solves the technical problem of poor sodium ion removal efficiency in the prior art.

[0005] Another objective of the first aspect of the present invention is to avoid damage to the silicon wafer from excessive cleaning.

[0006] A second aspect of the present invention is to provide a cleaning machine for the above-described cleaning method.

[0007] According to a first aspect of the present invention, the present invention provides a cleaning method based on silicon-glass bonds, comprising the following steps: Provides silicon-glass bonding; The silicon-glass bond is fixed on the cleaning machine platform, with the first surface of the silicon wafer of the silicon-glass bond facing the polishing head; The polishing head is controlled to polish the first surface of the silicon wafer, and polishing fluid is continuously supplied during the polishing process to remove the sodium ion contamination layer on the surface of the silicon wafer.

[0008] Optionally, the polishing solution is an alkaline polishing solution containing silica sol, wherein the concentration of SiO2 particles in the polishing solution ranges from 5wt% to 20wt%, and the pH value ranges from 9 to 10.5. The flow rate of the polishing fluid is in the range of 100 mL / min to 500 mL / min.

[0009] Optionally, in the step of controlling the polishing head to polish the first surface of the silicon wafer and continuously supplying polishing fluid during the polishing process to remove the sodium ion contamination layer on the surface of the silicon wafer, the pressure range of the polishing head is 0.5psi-2psi and the rotation speed range is 50rpm-200rpm.

[0010] Optionally, in the step of controlling the polishing head to polish the first surface of the silicon wafer and continuously supplying polishing fluid during the polishing process to remove the sodium ion contamination layer on the surface of the silicon wafer, the polishing time ranges from 10s to 60s, and the thickness of the sodium ion contamination layer removed is 0.1μm to 1μm.

[0011] Optionally, before the step of fixing the silicon-glass bond to the cleaning machine platform with the first surface of the silicon wafer of the silicon-glass bond facing the polishing head, the following steps are further included: The first surface of the silicon wafer is tested to obtain a first sodium ion concentration value on the first surface; When the first sodium ion concentration exceeds a first preset threshold, the polishing head is controlled to polish the silicon-glass bond.

[0012] Optionally, the following steps may also be included: The concentration of the second sodium ion in the polishing fluid on the cleaning machine is monitored in real time during the polishing process; When the second sodium ion concentration value is lower than the second preset threshold, the polishing head is controlled to stop polishing.

[0013] Optionally, the following steps may also be included: During the polishing process, the surface potential value of the first surface of the silicon wafer is monitored in real time, and the surface potential change rate is determined based on the surface potential value. When the second sodium ion concentration is lower than the second preset threshold and the surface potential change rate is lower than the set value, the polishing head is controlled to stop polishing.

[0014] Optionally, the polishing solution contains a sodium ion scavenger, which includes ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), or salts thereof.

[0015] Optionally, the step of controlling the polishing head to polish the first surface of the silicon wafer and continuously supplying polishing fluid during the polishing process to remove the sodium ion contamination layer on the surface of the silicon wafer specifically includes the following steps: The area where the first sodium ion concentration value exceeds the first preset threshold is designated as the area to be polished. The polishing head is controlled to polish the area to be polished.

[0016] According to a second aspect of the present invention, the present invention also provides a cleaning machine for cleaning silicon-glass bonds, wherein the above-described cleaning method includes: A polishing pad is provided on the surface of the polishing pad, and the silicon-glass bond is placed on the polishing pad; A polishing head, located above the polishing disk, is used to polish the surface of the silicon-glass bond.

[0017] This invention first provides a silicon-glass bond, then fixes the silicon-glass bond onto a cleaning machine platform with the first surface of the silicon wafer facing the polishing head. The polishing head then polishes the first surface of the silicon wafer, continuously supplying polishing fluid during the polishing process to remove the sodium ion contamination layer on the silicon wafer surface. This technical solution utilizes a chemical mechanical polishing (CMP) cleaning method to effectively remove the sodium ion contamination layer after silicon-glass bonding, not only effectively cleaning the contamination on the silicon wafer surface but also ensuring the normal operation of subsequent processes.

[0018] Furthermore, the present invention monitors the concentration of a second sodium ion in the polishing liquid on the cleaning machine in real time during the polishing process. When the concentration of the second sodium ion is lower than a second preset threshold, the polishing head is controlled to stop polishing, which can accurately remove the sodium ion contamination layer and avoid damage to the silicon wafer caused by over-polishing.

[0019] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0020] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a schematic flowchart of a cleaning method based on silicon-glass bonding according to an embodiment of the present invention; Figure 2 This is a schematic flowchart of a cleaning method based on silicon-glass bonds according to another embodiment of the present invention; Figure 3 This is a cross-sectional SEM image of a cleaned silicon wafer subjected to DRIE etching according to an embodiment of the present invention. Figure 4 This is a schematic structural diagram of a cleaning machine according to an embodiment of the present invention.

[0021] Figure label: 100-Cleaning machine, 200-Silicon-glass bond, 10-Polishing head, 20-Polishing disc, 30-Polishing pad, 40-Liquid dispenser, 50-Grinding tool. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] Figure 1 This is a schematic flowchart of a cleaning method based on silicon-glass bonds according to an embodiment of the present invention. Figure 1 As shown, in a specific embodiment, the cleaning method based on silicon-glass bonds includes the following steps: Step S100: Provide a silicon-glass bond; Step S200: Fix the silicon-glass bond to the cleaning machine platform, so that the first surface of the silicon wafer of the silicon-glass bond faces the polishing head; Step S300: Control the polishing head to polish the first surface of the silicon wafer, and continuously supply polishing fluid during the polishing process to remove the sodium ion contamination layer on the surface of the silicon wafer.

[0024] This embodiment utilizes the Chemical Mechanical Polishing (CMP) cleaning method to effectively remove the sodium ion contamination layer after silicon-glass bonding. This not only effectively cleans the contamination on the silicon wafer surface but also ensures the normal operation of subsequent processes.

[0025] The cleaning method proposed in this embodiment is far more efficient than traditional chemical cleaning methods, quickly achieving the required cleanliness. The surface roughness of the treated silicon wafer meets the stringent standards for surface morphology required by high-precision MEMS devices. This method has a wide process window, adaptable to various glass materials and bonding conditions, exhibiting excellent process adaptability, and can precisely remove sodium ion contamination layers without damaging the bonding interfaces. In terms of implementation, no modifications to existing CMP equipment are required; it can be directly integrated into standard equipment. Furthermore, compared to traditional strong acid and strong alkali cleaning processes, this cleaning method consumes fewer chemicals, and the waste liquid is easier to treat, combining environmental friendliness with operational safety.

[0026] In step S100, a silicon wafer and a glass sheet are first provided, and then the silicon wafer and the glass sheet are bonded together by a bonding process to form a silicon-glass bond.

[0027] In step S200, the cleaning machine is a CMP machine. The silicon-glass bond is placed in the fixing fixture of the CMP machine for fixation, ensuring that one side of the silicon wafer faces the CMP polishing head and the glass side is away from the polishing area. The silicon-glass bond is fixed by vacuum adsorption or mechanical clamping to prevent displacement during the process.

[0028] After step S300, the surface of the silicon-glass bond is thoroughly rinsed with deionized water, dried with nitrogen, and the removal effect of the sodium ion contamination layer is verified by XPS analysis to ensure that the residual sodium ion concentration is below 10. 15 atoms / cm 2 .

[0029] In some embodiments, the polishing slurry is an alkaline polishing slurry containing silica sol, and the concentration of SiO2 particles in the slurry ranges from 5wt% to 20wt%, for example, 5wt%, 10wt%, 15wt%, or 20wt%, etc., and the pH value ranges from 9 to 10.5, for example, 9, 10, or 10.5, etc. This embodiment limits the concentration range of SiO2 particles to 5wt%-20wt%, ensuring that the polishing slurry is efficient without damaging the silicon substrate, achieving an optimal balance between material removal and surface integrity. This embodiment limits the pH value range to 9-10.5, ensuring effective separation of the sodium ion contamination layer, preventing excessive chemical corrosion of the silicon substrate, and allowing sodium ions to be quickly carried away from the polishing interface.

[0030] In this embodiment, the silica sol-based polishing slurry forms a basic CMP removal path through the slight mechanical abrasion of the silicon surface by SiO2 particles. Under alkaline conditions, the oxide layer on the silicon surface undergoes a micro-dissolution reaction, and the two work together to achieve the removal of a very small amount of uniform material. The combination of the above concentration range and pH range results in a low removal rate, suitable for the slight removal requirements of this invention, which only require 0.1μm-1μm. This prevents over-polishing from causing silicon wafer thinning or increased bonding stress, and avoids damage to the silicon-glass bonding interface structure.

[0031] In some embodiments, the flow rate of the polishing fluid ranges from 100 mL / min to 500 mL / min, for example, 100 mL / min, 200 mL / min, 300 mL / min, 400 mL / min, or 500 mL / min. This flow rate range can significantly improve the removal efficiency and process controllability of the sodium ion contamination layer. In other embodiments, other flow rate values ​​of the polishing fluid can also be selected.

[0032] In some embodiments, in step S300, the pressure range of the polishing head is 0.5psi-2psi, for example, 0.5psi, 1psi, 1.5psi, or 2psi, and the rotation speed range is 50rpm-200rpm, for example, 50rpm, 100rpm, 150rpm, or 200rpm. This embodiment can generate a mild and controllable chemical mechanical polishing environment without damaging the silicon-glass bond structure, enabling the sodium ion contamination layer to be removed stably and selectively, and reducing the risk of surface damage, thereby significantly improving the contamination removal effect and the surface quality of the silicon wafer.

[0033] In some embodiments, in step S300, the polishing time ranges from 10s to 60s, for example, it can be 10s, 20s, 30s, 40s, 50s or 60s, and the thickness of the contaminant layer removed is 0.1μm to 1μm, for example, it can be 0.1μm, 0.5μm, 0.7μm or 1μm.

[0034] This embodiment employs short-time control of polishing time (10-60 seconds) to maintain a high removal rate while avoiding excessive material loss on the silicon wafer. Since the actual thickness of the sodium ion contamination layer is typically only submicron, limiting the removal thickness to 0.1-1 μm ensures that polishing only targets the sodium ion contamination layer or slightly damaged layer on the silicon wafer surface, without compromising its structural integrity. This time-removal-volume control strategy achieves selective removal of the sodium ion contamination layer, ensuring wafer surface cleanliness while minimizing the impact on wafer morphology, thickness uniformity, and bonding interface stability, thereby significantly improving the reliability and yield of subsequent processes.

[0035] Figure 2 This is a schematic flowchart of a cleaning method based on silicon-glass bonds according to another embodiment of the present invention. Figure 2 As shown, in another embodiment, before step S200, the following steps are also included: Step S110: Detect the first surface of the silicon wafer to obtain the first sodium ion concentration value of the first surface; Step S120: Determine whether the first sodium ion concentration value exceeds the first preset threshold. If yes, proceed to step S200; otherwise, end the process.

[0036] This embodiment detects the sodium ion concentration on the first surface of the silicon wafer and compares this concentration value with a preset threshold. This allows for timely triggering of subsequent cleaning steps when sodium ion contamination reaches or exceeds levels that affect process quality, thus achieving effective monitoring of the silicon wafer contamination status. This embodiment avoids unnecessary processing operations when contamination levels are low, improving production efficiency and reducing process costs. Furthermore, by taking timely measures when contamination levels exceed limits, it effectively prevents sodium ions from adversely affecting the performance of silicon wafer devices, improving product consistency and yield.

[0037] In some embodiments, the cleaning method further includes the following steps: Step S400: During the polishing process, the concentration of the second sodium ion in the polishing fluid on the cleaning machine is monitored in real time. In step S500, when the second sodium ion concentration value is lower than the second preset threshold, the polishing head is controlled to stop polishing.

[0038] This embodiment can determine whether the sodium ion contamination layer has been completely removed. Compared with traditional methods that rely on fixed time or fixed polishing amount, this scheme achieves dynamic determination of the polishing endpoint through online ion concentration monitoring, which can significantly improve the accuracy of the polishing process. Finally, after polishing, XPS analysis is used to verify the sodium ion removal effect.

[0039] In a preferred embodiment, the cleaning method further includes the following steps: Step 1: During the polishing process, monitor the surface potential value of the first surface of the silicon wafer in real time, and determine the surface potential change rate based on the surface potential value; Step 2: When the second sodium ion concentration value is lower than the second preset threshold and the surface potential change rate is lower than the set value, control the polishing head to stop polishing.

[0040] This embodiment monitors the surface potential of the first surface of the silicon wafer in real time during the polishing process and calculates its surface potential change rate based on this value. This reflects the change in charge state during the removal of the sodium ion contamination layer on the silicon wafer surface. When the second sodium ion concentration value is lower than a second preset threshold and the surface potential change rate is lower than a set value, the system determines that the sodium ion contamination layer has been basically removed and controls the polishing head to stop polishing, thereby achieving endpoint control based on dual criteria of chemical composition change and surface electrical property change.

[0041] This embodiment is more accurate and reliable than methods that rely solely on sodium ion concentration monitoring or fixed polishing time, effectively avoiding the residual risks caused by incomplete removal of the sodium ion contamination layer. Furthermore, by determining the polishing endpoint based on the stability of the surface potential change rate after the sodium ion contamination layer is removed, it avoids silicon wafer thickness loss, surface damage, or dislocation defects caused by continued polishing, thereby significantly improving silicon wafer surface quality and processing yield. In addition, the endpoint control method based on real-time feedback can reduce unnecessary polishing time, improve production efficiency, and reduce the cost of polishing fluid and consumables.

[0042] In some embodiments, the polishing slurry contains a sodium ion scavenger, including ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), or salts thereof. This can be understood as the polishing slurry containing not only a silica sol base but also a sodium ion scavenger. This embodiment, by introducing a sodium ion scavenger into the polishing slurry, effectively complexes and captures sodium ions released from the silicon wafer surface during polishing, preventing sodium ions from redepositing onto the silicon wafer surface in the polishing slurry, thereby significantly improving the thoroughness of sodium ion contamination layer removal. This embodiment reduces the risk of sodium ion re-adsorption during polishing, ensuring a low residual sodium ion level on the silicon wafer surface, further improving the cleanliness of the silicon wafer surface and process reliability.

[0043] In some embodiments, step S300 specifically includes the following steps: Step S310: The area where the first sodium ion concentration value exceeds the first preset threshold is taken as the area to be polished; Step S320: Control the polishing head to polish the area to be polished.

[0044] This embodiment enables precise positioning and selective polishing of contaminated areas on the silicon wafer surface, avoiding unnecessary polishing of uncontaminated areas and effectively reducing overall material loss and surface damage risk. Simultaneously, by targeting contaminated areas, the efficiency and reliability of sodium ion contamination layer removal are significantly improved, ensuring the silicon wafer surface cleanliness meets process requirements. Furthermore, selective polishing can shorten polishing time, reduce polishing fluid and consumable consumption, and improve production efficiency and yield.

[0045] The cleaning method described in this embodiment is particularly suitable for cleaning sodium ion contamination on the surfaces of devices such as microfluidic chips, MEMS devices, and PCR fluorescent chips.

[0046] Figure 3 This is a cross-sectional SEM image of a cleaned silicon wafer subjected to DRIE etching according to an embodiment of the present invention. Figure 3As can be seen, the etched sidewalls are smooth, the etch contours are regular, and the etch depth is uniform, without defects such as grass, black silicon, pitting, or rough sidewalls. This indicates that the cleaning method provided in this embodiment can effectively remove the sodium ion contamination layer and organic / particulate residues introduced during silicon-glass bonding, significantly improving the cleanliness of the silicon wafer surface and meeting the cleanliness requirements of deep silicon etching processes. Because surface contaminants are fully removed, the plasma etching reaction in the DRIE process is more stable, the etching rate remains consistent, and the anisotropy of the sidewalls is well guaranteed, thereby improving the yield and consistency of subsequent microstructure processing.

[0047] Figure 4 This is a schematic structural diagram of a cleaning machine 100 according to an embodiment of the present invention. Figure 4 As shown, this embodiment also provides a cleaning machine 100 for cleaning silicon-glass bonds 200. The cleaning machine 100 applies the cleaning method of any of the above embodiments. The cleaning machine 100 includes a polishing disk 20 and a polishing head 10. The surface of the polishing disk 20 is provided with a polishing pad 30, and the silicon-glass bond 200 is placed on the polishing pad 30. The polishing head 10 is located above the polishing disk 20 and is used to polish the surface of the silicon-glass bond 200.

[0048] In some embodiments, the cleaning machine 100 further includes a liquid dispenser 40 and a polisher 50. The liquid dispenser 40 is used to apply polishing liquid, and the polisher 50 is used to periodically polish the surface of the polishing pad 30 to maintain its flatness and roughness in order to maintain stable polishing performance.

[0049] The following examples will illustrate this in detail: Example 1: The application is based on PCR fluorescence chips.

[0050] An 8-inch silicon-Pyrex glass bond was fabricated using an anodic bonding process with a silicon wafer thickness of 500 μm. The specific bonding parameters were set as follows: temperature 300℃, voltage 1000V, and bonding time 5 minutes. XPS analysis of the silicon-Pyrex glass bond surface revealed a sodium ion concentration of 2 × 10⁻⁶. 15 atoms / cm 2The initial conditions exceeded the requirements for subsequent processes. The silicon-Pyrex glass bond was then placed side-up in the CMP machine fixture and fixed using vacuum adsorption at a pressure of -0.8 bar. An alkaline polishing slurry containing silica sol was then used, with SiO2 particles ranging from 90 nm to 110 nm in size, a concentration of 10 wt%, and a pH of 9.5. The polishing head pressure was set to 0.8 psi, the rotation speed to 80 rpm, and the slurry flow rate to 200 mL / min. Surface polishing was performed for 20 seconds, removing approximately 0.5 μm of material. Sodium ion concentration was monitored in real-time to ensure uniform removal. Finally, the surface was rinsed with deionized water for 1 minute and dried with nitrogen. XPS analysis was used to monitor the actual sodium ion concentration, ensuring the residual sodium ion concentration was below 10%. 15 atoms / cm 2 In Example 1, all areas of the first surface of the silicon wafer were cleaned.

[0051] Example 2: An 8-inch silicon-borosilicate glass bond was used to remove sodium ion-rich areas. First, SEM-EDS analysis revealed high sodium ion concentrations at the bond's edges, requiring localized cleaning. A local fixation method was employed, treating only a 2cm wide area at the edge of the silicon-borosilicate glass bond. Then, the CMP equipment parameters were adjusted: pressure 1.2 psi, rotation speed 100 rpm, scanning mode, and scanning speed 5 mm / s. Local polishing was performed for a total time of 15 seconds, removing 0.3 μm of sodium ion. Finally, deionized water rinsing and verification showed a significant reduction in sodium ion residue, meeting the requirements for subsequent processes.

[0052] This embodiment, through precise process control, can effectively remove sodium ion contamination while ensuring the integrity of the bonding structure, providing clean surface conditions for subsequent precision machining, and significantly improving the success rate of device manufacturing and product quality.

[0053] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A cleaning method based on silicon-glass bonds, characterized in that, Includes the following steps: Provides silicon-glass bonding; The silicon-glass bond is fixed on the cleaning machine platform, with the first surface of the silicon wafer of the silicon-glass bond facing the polishing head; The polishing head is controlled to polish the first surface of the silicon wafer, and polishing fluid is continuously supplied during the polishing process to remove the sodium ion contamination layer on the surface of the silicon wafer.

2. The cleaning method according to claim 1, characterized in that, The polishing solution is an alkaline polishing solution containing silica sol, wherein the concentration of SiO2 particles in the polishing solution ranges from 5wt% to 20wt%, and the pH value ranges from 9 to 10.

5. The flow rate of the polishing fluid is in the range of 100 mL / min to 500 mL / min.

3. The cleaning method according to claim 2, characterized in that, In the step of controlling the polishing head to polish the first surface of the silicon wafer and continuously supplying polishing fluid during the polishing process to remove the sodium ion contamination layer on the surface of the silicon wafer, The polishing head has a pressure range of 0.5psi-2psi and a rotation speed range of 50rpm-200rpm.

4. The cleaning method according to claim 3, characterized in that, In the step of controlling the polishing head to polish the first surface of the silicon wafer and continuously supplying polishing fluid during the polishing process to remove the sodium ion contamination layer on the surface of the silicon wafer, the polishing time ranges from 10s to 60s, and the thickness of the sodium ion contamination layer removed is 0.1μm to 1μm.

5. The cleaning method according to claim 4, characterized in that, Before the step of fixing the silicon-glass bond to the cleaning machine platform with the first surface of the silicon wafer of the silicon-glass bond facing the polishing head, the following steps are also included: The first surface of the silicon wafer is tested to obtain a first sodium ion concentration value on the first surface; When the first sodium ion concentration exceeds a first preset threshold, the polishing head is controlled to polish the silicon-glass bond.

6. The cleaning method according to any one of claims 1-5, characterized in that, It also includes the following steps: The concentration of the second sodium ion in the polishing fluid on the cleaning machine is monitored in real time during the polishing process; When the second sodium ion concentration value is lower than the second preset threshold, the polishing head is controlled to stop polishing.

7. The cleaning method according to claim 6, characterized in that, It also includes the following steps: During the polishing process, the surface potential value of the first surface of the silicon wafer is monitored in real time, and the surface potential change rate is determined based on the surface potential value. When the second sodium ion concentration is lower than the second preset threshold and the surface potential change rate is lower than the set value, the polishing head is controlled to stop polishing.

8. The cleaning method according to any one of claims 2-5, characterized in that, The polishing solution contains a sodium ion scavenger, which includes ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), or their salts.

9. The cleaning method according to claim 5, characterized in that, The step of controlling the polishing head to polish the first surface of the silicon wafer and continuously supplying polishing fluid during the polishing process to remove the sodium ion contamination layer on the surface of the silicon wafer specifically includes the following steps: The area where the first sodium ion concentration value exceeds the first preset threshold is designated as the area to be polished. The polishing head is controlled to polish the area to be polished.

10. A cleaning machine for cleaning silicon-glass bonds, characterized in that, The cleaning method according to any one of claims 1-9 is characterized by comprising: A polishing pad is provided on the surface of the polishing pad, and the silicon-glass bond is placed on the polishing pad; A polishing head, located above the polishing disk, is used to polish the surface of the silicon-glass bond.

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