Wafer Cleaning System and Method

Abstract

This invention provides a wafer cleaning system and method. In this wafer cleaning system, a reagent tank holds the cleaning solution, a pre-circulation unit preheats the cleaning solution in the reagent tank, and a process supply unit supplies the pre-circulated cleaning solution from the reagent tank to the process chamber. The pre-circulation unit includes a particle agglomerator and a first filter. During preheating, the cleaning solution circulates between the reagent tank, the first filter, and the particle agglomerator. The particle agglomerator adsorbs charged particles in the cleaning solution and agglomerates them into clusters. The first filter removes the clusters that have detached from the particle agglomerator. This effectively reduces charged particles in the cleaning solution, thereby reducing spherical residues after wafer cleaning, improving product yield, without affecting production capacity, and at a lower cost. The wafer cleaning system executes the wafer cleaning method provided by this invention during operation.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a wafer cleaning system and method. Background Technology

[0002] Currently, the cleaning solutions used after dry etching of wafers (such as ST250 or SYS9058) have high viscosity, causing unstable colloidal particles in the solution system. These particles easily agglomerate during solution transportation and use, forming charged particles. Therefore, after cleaning with this solution, a large number of ball defects easily appear on the wafer surface due to the adhesion, agglomeration, and sliding of these charged particles. These ball defects can affect subsequent processes such as copper plating, impacting product yield.

[0003] To address charged particles in the cleaning fluid, one approach is to continuously reduce the size of the equipment's chemical filter and enhance its chemical adsorption capacity to decrease these particles, thereby reducing spherical residues after wafer cleaning. However, chemical filters that meet these requirements are expensive, significantly increasing costs. Furthermore, some equipment, such as single-wafer cleaning machines, have poor compatibility with small-sized filters (small-sized filters cause significant pressure loss), and replacing them with smaller filters can lead to overload of the circulation system pumps.

[0004] Another approach is to run a large number of dummy filters before cleaning the product flakes to adsorb and remove charged particles, thereby reducing spherical residues after cleaning. However, this method will take up machine production time and affect the machine's WPH (Wafer Per Hour). Summary of the Invention

[0005] One of the objectives of this invention is to provide a wafer cleaning system and method that can effectively reduce charged particles in the cleaning solution, thereby reducing spherical residues after wafer cleaning, improving product yield, without affecting production capacity, and at a lower cost.

[0006] To achieve the above objectives, the wafer cleaning system provided by the present invention includes: a reagent tank for holding cleaning fluid; a pre-circulation unit for preheating the cleaning fluid in the reagent tank; and a process supply unit for supplying the cleaning fluid treated by the pre-circulation unit in the reagent tank to a process chamber; wherein, the pre-circulation unit includes a particle agglomerator and a first filter, and during the preheating process, the cleaning fluid circulates between the reagent tank, the first filter, and the particle agglomerator, the particle agglomerator adsorbs charged particles in the cleaning fluid and agglomerates the charged particles into aggregated particles, and the first filter filters out the aggregated particles that have detached from the particle agglomerator.

[0007] Optionally, the wafer cleaning system includes a first chemical tank, a second chemical tank, a second valve, and an eighth valve. The B end of the second valve is connected to the first chemical tank, the C end of the second valve is connected to the second chemical tank, the A end of the second valve is connected to the inlet of the first filter, the outlet of the first filter is connected to the inlet of the particle agglomerator, the outlet of the particle agglomerator is connected to the A end of the eighth valve, the B end of the eighth valve is connected to the first chemical tank, and the C end of the eighth valve is connected to the second chemical tank.

[0008] Optionally, the wafer cleaning system includes a third valve and a fourth valve. The B end of the third valve is connected to the first chemical solution tank, the C end of the third valve is connected to the second chemical solution tank, the A end of the third valve is connected to the inlet of the process chamber, the outlet of the process chamber is connected to the A end of the fourth valve, the B end of the fourth valve is connected to the first chemical solution tank, and the C end of the fourth valve is connected to the second chemical solution tank.

[0009] Optionally, the pre-circulation unit further includes a first heater, the inlet of which is connected to end A of the second valve, and the outlet of which is connected to the inlet of the first filter; the process supply unit includes a second heater and a second filter, the inlet of which is connected to end A of the third valve, the outlet of which is connected to the inlet of the second filter, and the outlet of the second filter is connected to the inlet of the process chamber.

[0010] Optionally, the particle agglomerator includes a reaction plate. The cleaning liquid flowing through the particle agglomerator rubs against the reaction plate, causing the reaction plate to become positively charged. Negatively charged particles in the cleaning liquid are adsorbed on the surface of the reaction plate and agglomerate to form agglomerated particles.

[0011] Optionally, the material of the coating on the surface of the reaction plate includes nitrogen-doped silicon carbide, silicon oxide, or silicon nitride.

[0012] Optionally, the particle agglomerator includes two reaction plates arranged opposite each other, with the edges of the two reaction plates sealed to use the gap between the two reaction plates as a flow channel for the cleaning liquid.

[0013] Optionally, the particle agglomerator further includes a drug inflow pipe, which is parallel to the surface of the reaction plate, and the flow direction of the cleaning liquid through the reaction plate is parallel to the surface of the reaction plate.

[0014] Optionally, the particle agglomerator is tubular, and the inner wall of the tube of the particle agglomerator has multiple friction particles. The cleaning fluid flowing through the particle agglomerator rubs against the friction particles, causing the inner wall of the tube of the particle agglomerator to become positively charged. The negatively charged particles in the cleaning fluid are adsorbed on the inner wall of the tube of the particle agglomerator and agglomerate to form the agglomerated particles.

[0015] Optionally, the material of the friction particles includes nitrogen-doped silicon carbide, silicon oxide, or silicon nitride.

[0016] Optionally, both ends of the pipeline of the agglomerator are provided with sieve plates, and the friction particles are disposed between the sieve plates.

[0017] Optionally, the pre-circulation unit includes a plurality of the particle agglomerators connected in parallel in the pre-circulation unit.

[0018] Optionally, the pre-circulation unit includes an abnormality handling pipeline, one end of which is connected to the inlet of the colloidal agglomerator and the other end of which is connected to the outlet of the colloidal agglomerator. The abnormality handling pipeline has a valve, which is opened when the colloidal agglomerator is blocked, allowing the cleaning fluid to flow directly back to the medicine tank without passing through the colloidal agglomerator.

[0019] Optionally, the cleaning solution is used to clean the wafer after dry etching.

[0020] This application also provides a wafer cleaning method. The wafer cleaning method includes: pre-treating a cleaning solution in a chemical tank, the pre-treating including preheating and removal of charged particles; supplying the pre-treated cleaning solution to a process chamber; wherein, during the preheating process, charged particles in the cleaning solution are adsorbed by a particle agglomerator and agglomerated into aggregated particles, and then the aggregated particles detached from the particle agglomerator are removed by a first filter.

[0021] Optionally, at least two of the aforementioned liquid tanks are provided; while the cleaning solution in one of the liquid tanks is supplied to the process chamber, the cleaning solution in the remaining liquid tanks is preheated and treated to remove charged particles.

[0022] Optionally, at least two of the aforementioned chemical solution tanks are provided; when the cleaning solution in one of the chemical solution tanks reaches its service life during the process of supplying the solution, the remaining chemical solution tanks are switched to continue supplying the solution to the process.

[0023] In the wafer cleaning system and method provided by this invention, during the preheating process of the cleaning solution in the reagent tank, a particle agglomerator adsorbs charged particles in the cleaning solution and agglomerates them into clustered particles. A first filter then removes the clustered particles that have detached from the particle agglomerator. This reduces the number of charged particles in the cleaning solution during preheating, effectively removing them and thus reducing spherical residues after wafer cleaning, improving product yield without affecting production capacity. It also avoids the use of expensive small-size filters, saving costs and having a wide range of applications.

[0024] Furthermore, at least two of the aforementioned cleaning solution tanks are provided. While the cleaning solution in one tank is supplied to the process chamber, the cleaning solution in the remaining tanks is preheated and treated to remove charged particles. When the cleaning solution in one tank reaches its service life during the process supply, the remaining tanks are switched to continue the process supply. This allows for preheating and charged particle removal in other tanks while some tanks are supplying the process solution, providing ample time for these processes without interrupting production. This improves the removal efficiency of charged particles from the cleaning solution and enables continuous process supply, thus increasing production capacity. Attached Figure Description

[0025] Figure 1 This is a structural diagram of a wafer cleaning system provided in an embodiment of the present invention.

[0026] Figure 2 This is a piping layout diagram of a wafer cleaning system provided in an embodiment of the present invention.

[0027] Figure 3 This is a structural diagram of a particle agglomerator provided in an embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram illustrating the principle of adsorbing and agglomerating charged particles on a reaction plate in one embodiment of the present invention.

[0029] Figure 5 This is a schematic diagram of the structure of a particle agglomerator provided in another embodiment of the present invention.

[0030] Explanation of reference numerals in the attached drawings: 10-Drug solution tank; 20-Pre-circulation unit; 30-Process liquid supply unit; 40-Process chamber; 111-First drug solution tank; 112-Second drug solution tank; 121-First heater; 122-Second heater; 131-First filter; 132-Second filter; 141-First pump; 142-Second pump; 143-Third pump; 151-First valve; 152-Second valve; 153-Third valve; 154-Fourth valve; 155-Fifth valve; 156-Sixth valve; 157-Seventh valve; 158-Eighth valve; 161-First thermometer; 162-Second thermometer; 170-Particle agglomerator; 171-Reaction plate; 172-Drug solution inflow pipeline; 173-Friction particles; 174-Sieve plate; 200-Charged particles. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0032] As used herein, the singular forms “a,” “an,” and “the” include plural objects unless otherwise expressly indicated. As used herein, the term “or” is generally used to include “and / or” unless otherwise expressly indicated. As used herein, the term “a number” is generally used to include “at least one” unless otherwise expressly indicated. As used herein, the term “at least two” is generally used to include “two or more” unless otherwise expressly indicated. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature, unless otherwise expressly indicated.

[0033] Figure 1 This is a structural diagram of a wafer cleaning system provided in an embodiment of the present invention. Figure 2 This is a piping layout diagram of a wafer cleaning system according to an embodiment of the present invention. (Reference) Figure 1 and Figure 2As shown, the wafer cleaning system provided in this embodiment includes a chemical tank 10, a pre-circulation unit 20, a process supply unit 30, and a process chamber 40. The chemical tank 10 is used to carry the cleaning solution. The pre-circulation unit 20 is used to preheat the cleaning solution in the chemical tank 10. The process supply unit 30 is used to supply the cleaning solution in the chemical tank 10 after being treated by the pre-circulation unit 20 to the process chamber 40. The pre-circulation unit 20 is also used to remove charged particles from the cleaning solution in the chemical tank 10. The pre-circulation unit 20 includes a particle agglomerator 170 and a first filter 131. During the preheating process, the cleaning solution circulates between the chemical tank 10, the first filter 131, and the particle agglomerator 170. The particle agglomerator 170 adsorbs charged particles in the cleaning solution and agglomerates them into aggregated particles. The first filter 131 filters out the aggregated particles that have detached from the particle agglomerator 170. In this way, charged particles in the cleaning solution can be reduced during the preheating process. That is, the charged particles are removed during the preheating process, which can reduce the spherical residues after wafer cleaning, improve product yield, and not affect production capacity. It can also avoid the use of expensive small-size filters, which helps to save costs and has a wide range of applications.

[0034] In one embodiment of this application, the wafer cleaning system may include at least two cleaning solution tanks 10, each of which is connected to a pre-circulation unit 20 and a process liquid supply unit 30. The pre-circulation unit 20 can preheat and remove charged particles from the cleaning solution in each cleaning solution tank 10, and the process liquid supply unit 30 can deliver the cleaning solution in each cleaning solution tank 10 to the process chamber 40 for wafer cleaning. The piping of the pre-circulation unit 20 and the process liquid supply unit 30 is independent of each other.

[0035] In this system, when the process supply unit 30 supplies cleaning fluid from one chemical tank 10 to the process chamber 40, the pre-circulation unit 20 can preheat the cleaning fluid in the remaining chemical tanks 10, simultaneously performing charge removal treatment during the preheating process. When the cleaning fluid in one of the chemical tanks reaches its service life during the process supply, the remaining chemical tanks are switched to continue the process supply. This allows for ample time for preheating and charge removal treatment without interrupting machine production, improving the removal efficiency of charge particles in the cleaning fluid and enabling continuous process supply, thus contributing to increased production capacity.

[0036] In this embodiment, the medicine tank 10 includes a first medicine tank 111 and a second medicine tank 112 as an example for illustration. Both the first medicine tank 111 and the second medicine tank 112 are connected to the pre-circulation unit 20 and the process supply unit 30.

[0037] refer to Figure 2As shown, the cleaning fluid in the first liquid tank 111 and the second liquid tank 112 both come from the plant (i.e., the liquid is supplied by the plant). The first valve 151 can control the liquid from the plant to fill the first liquid tank 111 or the second liquid tank 112. When the A and C ends of the first valve 151 are open and the B end is closed, the liquid is supplied to the first liquid tank 111. When the A and B ends of the first valve 151 are open and the C end is closed, the liquid is supplied to the second liquid tank 112.

[0038] In one embodiment, the wafer cleaning system includes a second valve 152 and an eighth valve 158; the second valve 152 controls the cleaning fluid from the first chemical tank 111 or the second chemical tank 112 to flow to the pre-circulation unit 20; the eighth valve 158 controls the cleaning fluid flowing through the pre-circulation unit 20 to flow back to the first chemical tank 111 or the second chemical tank 112.

[0039] Specifically, end B of the second valve 152 is connected to the first liquid tank 111, end C of the second valve 152 is connected to the second liquid tank 112, end A of the second valve 152 is connected to the inlet of the first filter 131, the outlet of the first filter 131 is connected to the inlet of the particle agglomerator 170, the outlet of the particle agglomerator 170 is connected to end A of the eighth valve 158, end B of the eighth valve 158 is connected to the first liquid tank 111, and end C of the eighth valve 158 is connected to the second liquid tank 112. When ends B and A of the second valve 152 are open and end C is closed, the cleaning fluid in the first liquid tank 111 can flow into the pre-circulation unit 20; when ends C and A of the second valve 152 are open and end B is closed, the cleaning fluid in the second liquid tank 112 can flow into the pre-circulation unit 20. When the A and B ends of the eighth valve 158 are open and the C end is closed, the cleaning fluid processed by the pre-circulation unit 20 can flow back to the first liquid tank 111; when the A and C ends of the eighth valve 158 are open and the B end is closed, the cleaning fluid processed by the pre-circulation unit 20 can flow back to the second liquid tank 112.

[0040] The first heater 121, the first filter 131, and the particle agglomerator 170 of the pre-circulation unit 20 are disposed in the pipeline between the second valve 152 and the eighth valve 158; the cleaning fluid flowing into the pre-circulation unit 20 flows through the first heater 121, the first filter 131, and the particle agglomerator 170 and then returns to the medicine tank 10 and circulates between the medicine tank 10, the first heater 121, the first filter 131, and the particle agglomerator 170 to repeatedly perform the de-charged particle treatment.

[0041] refer to Figure 2As shown, the pre-circulation unit 20 may further include a first thermometer 161 and a first pump 141; the inlet of the first pump 141 is connected to end A of the second valve 152, the outlet of the first pump 141 is connected to the inlet of the first heater 121, and the outlet of the first heater 121 is connected to the inlet of the first filter 131; the first thermometer 161 is disposed in the pipeline between the first pump 141 and the first heater 121. The first thermometer 161 is used to monitor the temperature of the cleaning fluid flowing through the pre-circulation unit 20. When the temperature of the flowing cleaning fluid is detected to be below the preset preheating temperature, the first heater 121 heats the flowing cleaning fluid; the first pump 141 is used to pump the cleaning fluid in the medicine tank 10 into the pre-circulation unit 20.

[0042] For example, the cleaning solution can be a cleaning solution used to clean wafers after dry etching. For instance, the cleaning solution can be an organic cleaning solution with high viscosity, such as ST250 or SYS9058. The colloidal particles in the cleaning solution readily aggregate to form charged particles during transport and use. These charged particles are small, soft particles that cannot be detected by a particle analyzer and cannot be filtered by conventional filters before agglomeration.

[0043] Figure 3 This is a structural diagram of a particle agglomerator provided in an embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the principle of adsorbing and agglomerating charged particles using a reaction plate in one embodiment of the present invention. (Reference) Figure 3 and Figure 4 As shown, in one embodiment of this application, the particle agglomerator 170 includes a reaction plate 171. The cleaning liquid flowing through the particle agglomerator 170 rubs against the reaction plate 171, causing the reaction plate 171 to become positively charged. The negatively charged particles 200 in the cleaning liquid are adsorbed onto the surface of the reaction plate 171 and agglomerate to form aggregated particles. The size of the aggregated particles is larger than the size of the charged particles 200 before agglomeration, so that the small soft impurities that could not be filtered by the first filter 131 are transformed into large particles that can be filtered through agglomeration. When the aggregated particles formed by the agglomeration of the charged particles 200 reach a certain size, they will detach from the adsorption of the reaction plate 171 due to the impact of the medicine (i.e., the cleaning liquid) and re-enter the medicine. The aggregated particles can then be removed by the filtration of the first filter 131. This reduces the number of impurities and charged particles in the medicine, thereby reducing agglomeration defects (i.e., spherical residues) on the product.

[0044] The material of the surface coating of the reaction plate 171 includes, but is not limited to, nitrogen-doped silicon carbide (NDC), silicon oxide, or silicon nitride. Preferably, the material of the surface coating of the reaction plate 171 is nitrogen-doped silicon carbide, which does not react with the cleaning solution and can generate a positive charge through friction with the cleaning solution. In some embodiments, the material of the surface coating of the reaction plate 171 can be silicon oxide or silicon nitride. In this way, the friction between the cleaning solution and the surface coating of the reaction plate 171 can generate a positive charge. However, silicon oxide and silicon nitride may react slightly with the cleaning solution. But usually, the material to be cleaned by the cleaning solution is silicon oxide and / or silicon nitride, so no new substances are introduced, and the impact on the solution is negligible. Accordingly, in order to ensure the removal effect of charged particles, the friction component (i.e., the reaction plate) or the entire particle agglomerator 170 can be replaced periodically, and the replacement frequency can be determined according to the thickness of the silicon oxide or silicon nitride.

[0045] For example, the thickness of the coating on the surface of the reaction plate 171 can be 50 nm to 100 nm, but is not limited thereto.

[0046] In one embodiment of this application, reference is made to... Figure 3 As shown, the particle agglomerator 170 may include two opposing reaction plates 171, with their edges sealed to use the gap between them as a flow channel for the cleaning fluid. The particle agglomerator 170 may also include a drug inflow pipe 172, which is parallel to the surface of the reaction plates 171. The flow direction of the cleaning fluid through the reaction plates 171 is parallel to the surface of the reaction plates 171, i.e., the cleaning fluid flows along the elongation direction of the reaction plates 171. Figure 3 The cleaning solution flows vertically downwards across the surface of the reaction plate 171, resulting in greater friction between the cleaning solution and the reaction plate 171, generating more charge and thus improving the removal of charged particles from the cleaning solution.

[0047] For example, the distance between the two reaction plates 171 can be 2mm to 4mm, such as 3mm. This ensures the normal flow of the cleaning fluid and a large frictional force between the cleaning fluid and the reaction plates 171. Of course, the distance between the two reaction plates 171 can be adjusted as needed. The width and length of the reaction plates 171 can be set according to the flow rate and pressure range of the circulation pipeline of the pre-circulation unit 20.

[0048] In some embodiments of this application, the pre-circulation unit 20 may include multiple particle agglomerators 170, which can be connected in parallel in the pre-circulation unit 20. This can meet the high flow rate requirements of the pre-circulation unit 20 and avoid the reaction plate 171 being too wide. In some embodiments of this application, the pre-circulation unit 20 may also include multiple particle agglomerators 170 connected in series, which can improve the removal effect of charged particles in the cleaning fluid.

[0049] Figure 5 This is a schematic diagram of a particle agglomerator provided in another embodiment of the present invention. (See reference) Figure 5 As shown, in another embodiment of this application, the particle agglomerator 170 is tubular. The inner wall of the agglomerator 170 has multiple friction particles 173. The cleaning fluid flowing through the agglomerator 170 rubs against the friction particles 173, causing the inner wall of the agglomerator 170 to become positively charged. The negatively charged particles in the cleaning fluid are adsorbed onto the inner wall of the agglomerator 170 and agglomerate to form agglomerated particles. For example, the pre-circulation unit 20 may include two or more agglomerators 170 connected in parallel to meet flow requirements.

[0050] For example, the material of the friction particles 173 includes, but is not limited to, nitrogen-doped silicon carbide, silicon oxide, or silicon nitride. Multiple friction particles 173 can be uniformly distributed on the inner wall of the conduit of the particle agglomerator 170.

[0051] refer to Figure 5 As shown, both ends of the pipe of the particle agglomerator 170 can be equipped with sieve plates 174, and friction particles 173 are disposed between the sieve plates 174. The sieve plates 174 are used to prevent the detached friction particles 173 from entering the process chamber 40 with the flow of the cleaning fluid. It is worth noting that the size of the friction particles 173 needs to be larger than the size of the agglomerated particles formed by the agglomeration of charged particles, and the size of the holes in the sieve plate 174 needs to be smaller than the size of the friction particles 173 but larger than the size of the agglomerated particles. In this way, the sieve plate can prevent the flow of friction particles 173 without affecting the outflow of agglomerated particles.

[0052] refer to Figure 2 As shown, the pre-circulation unit 20 may also include an abnormality handling pipeline. One end of the abnormality handling pipeline is connected to the inlet of the particle agglomerator 170 and the other end is connected to the outlet of the particle agglomerator 170. The abnormality handling pipeline has a sixth valve 156. When the particle agglomerator 170 is blocked, the sixth valve 156 of the abnormality handling pipeline is opened, and the cleaning fluid can flow directly back to the liquid tank 10 without passing through the particle agglomerator 170. This ensures that the cleaning fluid can circulate in the pre-circulation unit 20 when the particle agglomerator 170 is blocked.

[0053] refer to Figure 1 and Figure 2 As shown, the wafer cleaning system also includes a third valve 153 and a fourth valve 154; the process chamber 40 is disposed in the pipeline between the third valve 153 and the fourth valve 154.

[0054] The third valve 153 controls the flow of cleaning fluid from the first liquid tank 111 or the second liquid tank 112 to the process chamber 40. The fourth valve 154 controls the return flow of cleaning fluid flowing through the process chamber 40 to the first liquid tank 111 or the second liquid tank 112.

[0055] Specifically, end B of the third valve 153 is connected to the first liquid tank 111, end C of the third valve 153 is connected to the second liquid tank 112, end A of the third valve 153 is connected to the inlet of the process chamber 40, the outlet of the process chamber 40 is connected to end A of the fourth valve 154, end B of the fourth valve 154 is connected to the first liquid tank 111, and end C of the fourth valve 154 is connected to the second liquid tank 112. When ends A and B of the third valve 153 are open and end C is closed, the cleaning fluid from the first liquid tank 111 can flow into the process chamber 40; when ends A and C of the third valve 153 are open and end B is closed, the cleaning fluid from the second liquid tank 112 can flow into the process chamber 40. When ends A and B of the fourth valve 154 are open and end C is closed, the cleaning fluid flowing through the process chamber 40 flows back to the first liquid tank 111; when ends A and C of the fourth valve 154 are open and end B is closed, the cleaning fluid flowing through the process chamber 40 flows back to the second liquid tank 112.

[0056] The process supply unit 30 includes a second pump 142, a second thermometer 162, a second heater 122, and a second filter 132, all disposed in a pipeline between the third valve 153 and the fourth valve 154. Specifically, the inlet of the second pump 142 is connected to end A of the third valve 153, and its outlet is connected to the inlet of the second heater 122. The outlet of the second heater 122 is connected to the inlet of the second filter 132, and the outlet of the second filter 132 is connected to the inlet of the process chamber 40. The second thermometer 162 is disposed in the pipeline between the second pump 142 and the second heater 122. The second pump 142 is used to pump the cleaning fluid from the chemical tank 10 into the process supply unit 30. The second thermometer 162 is used to monitor the temperature of the cleaning fluid flowing through the process supply unit 30. The second heater 122 is used to heat the cleaning fluid flowing through the process supply unit 30. The second filter 132 is used to filter the cleaning fluid passing through the process supply unit 30 to reduce impurities entering the process chamber. A seventh valve 157 is provided between the process liquid supply unit 30 and the process chamber 40. When the seventh valve 157 is opened, the cleaning liquid in the process liquid supply unit 30 can enter the process chamber.

[0057] refer to Figure 2As shown, the process liquid supply unit 30 transmits the cleaning liquid flowing through the second thermometer 162, the second heater 122 and the second filter 132 to the process chamber 40 to clean the wafer. After the wafer is cleaned in the process chamber 40, the cleaning liquid flows back to the corresponding chemical tank 10 through the process liquid supply unit 30.

[0058] refer to Figure 2 As shown, the wafer cleaning system also includes a discharge pipeline connected to a first chemical solution tank 111 and a second chemical solution tank 112. The discharge pipeline is controlled by a fifth valve 155; when ends A and B of the fifth valve 155 are open and end C is closed, the first chemical solution tank 111 can discharge liquid; when ends A and C of the fifth valve 155 are open and end B is closed, the second chemical solution tank 112 can discharge liquid.

[0059] It should be noted that the service life of the cleaning solution in the chemical solution tank 10 can be set according to the process circulation time of the cleaning solution (i.e., the circulation time in the process chamber 40), the number of wafers being cleaned, or the number of particles in the cleaning solution; when the cleaning solution in the chemical solution tank 10 reaches its service life, it can be discharged to the plant end through the drain pipe.

[0060] The following example illustrates the workflow of a wafer cleaning system.

[0061] The first step involves filling the cleaning solution tank 10 with cleaning fluid. For example, refer to... Figure 2 As shown, when the wafer cleaning system triggers the liquid supply signal, the cleaning fluid is supplied from the plant terminal. Terminals A and C of the first valve 151 are opened and terminal B is closed, and the cleaning fluid enters the first liquid tank 111. After the cleaning fluid reaches the predetermined level, the first valve 151 is closed, and the liquid supply stops.

[0062] In the second execution step, the pre-circulation unit 20 preheats the cleaning solution and removes charged particles. (Reference) Figure 2 As shown, the second valve 152 is open at ends A and B and closed at end C, and the first pump 141 starts working. The cleaning fluid in the first liquid tank 111 flows through the second valve 152, the first heater 121, the first filter 131, and the particle agglomerator 170, and then returns to the first liquid tank 111 to complete a single cycle. Multiple cycles can be performed as needed. For example, the pre-circulation unit 20 continues to work (i.e., continuously circulates the cleaning fluid) until the system triggers a switching signal.

[0063] In the third execution step, the process liquid supply unit 30 supplies the cleaning solution treated by the pre-circulation unit 20 to the process chamber 40 for wafer cleaning. For example, see reference... Figure 2As shown, when the wafer cleaning system triggers a switching signal, the first pump 141 stops working, the second valve 152 closes, and the pre-circulation unit 20 stops circulating the cleaning solution in the first chemical tank 111; the second pump 142 starts working, the A and B ends of the third valve 153 open and the C end closes, the A and B ends of the fourth valve 154 open and the C end closes, and the cleaning solution in the first chemical tank 111 flows through the third valve 153, the second pump 142, the second heater 122, the second filter 132, the process chamber 40, and the fourth valve 154, returning... After the first liquid tank 111 completes a single process cycle, and the process cycle is repeated for x hours (i.e., the cleaning fluid in the first liquid tank 111 circulates in the process chamber for x hours) and before the cleaning fluid in the first liquid tank 111 reaches its service life, the second liquid tank 112 triggers a liquid supply signal, and processes one and two are executed on the second liquid tank 112; after the cleaning fluid in the first liquid tank 111 reaches its service life (the service life is set to y hours, y≥x+2), a switching signal is triggered, and the first liquid tank 111 triggers a discharge signal to execute process 4.

[0064] Execution process 4: Liquid discharge. Specifically, the first liquid tank 111 triggers a discharge signal, the second pump 142 stops working, the third valve 153 closes, the A and B ends of the fifth valve 155 open and the C end closes, the third pump 143 starts working, and the first liquid tank 111 begins to discharge liquid; after the first liquid tank 111 reaches the predetermined liquid level, the third pump 143 stops, the fifth valve 155 closes, and the first liquid tank 111 completes the liquid discharge process. The discharge process can be completed in a relatively short time, and it is necessary to set the liquid supply signal to be triggered only after the liquid discharge process is completed; that is, liquid supply to the first liquid tank 111 should only begin after the discharge process is finished.

[0065] It should be noted that when the first chemical tank 111 stops supplying cleaning fluid to the process chamber 40, i.e., after the first chemical tank 111 completes process three, process three can be performed on the second chemical tank 112 as needed. This way, the process in the process chamber 40 does not need to be stopped, which helps to increase production capacity. Furthermore, while process three is being performed on the first chemical tank 111, processes one and two are being performed on the second chemical tank 112. This way, preheating the cleaning fluid and removing charged particles from the second chemical tank 112 does not consume additional time and does not affect WPH (Wastewater Permeability).

[0066] The wafer cleaning system provided by the present invention includes a chemical tank 10, a pre-circulation unit 20, and a process supply unit 30. The chemical tank 10 is used to carry the cleaning solution, the pre-circulation unit 20 is used to preheat the cleaning solution in the chemical tank 10, and the process supply unit 30 is used to supply the cleaning solution in the chemical tank after being treated by the pre-circulation unit 20 to the process chamber 40. The pre-circulation unit 20 includes a particle agglomerator 170 and a first filter 131. During the preheating process, the cleaning solution circulates between the chemical tank 10, the first filter 131, and the particle agglomerator 170. The particle agglomerator 170 adsorbs charged particles in the cleaning solution and agglomerates the charged particles into aggregated particles. The first filter 131 filters out the aggregated particles that have detached from the particle agglomerator 170. This reduces charged particles in the cleaning solution during preheating, thereby reducing spherical residues after wafer cleaning, improving product yield, and not affecting production capacity. It also avoids the use of expensive small-sized filters, saving costs and having a wide range of applications.

[0067] Furthermore, the wafer cleaning system includes at least two cleaning solution tanks 10, each connected to a pre-circulation unit 20 and a process supply unit 30. While the process supply unit 30 supplies cleaning solution from one cleaning solution tank 10 to the process chamber 40, the pre-circulation unit 20 preheats and removes charged particles from the cleaning solution in the remaining cleaning solution tanks 10. This allows for preheating and charged particle removal from other cleaning solution tanks 10 while some tanks are being supplied with process solution, providing ample time for charged particle removal and thus improving the removal efficiency of charged particles in the cleaning solution without affecting production capacity.

[0068] This application embodiment also provides a wafer cleaning method, wherein the wafer cleaning system described above performs the wafer cleaning method during operation.

[0069] refer to Figure 2 As shown, the wafer cleaning method provided in this embodiment includes: pre-treating the cleaning solution in the chemical solution tank, the pre-treatment including preheating treatment and removal of charged particles; supplying the pre-treated cleaning solution to the process chamber; wherein, during the preheating treatment, the removal of charged particles is performed, the removal of charged particles includes adsorbing charged particles in the cleaning solution through a particle agglomerator and agglomerating the charged particles into agglomerated particles, and then filtering the agglomerated particles that have detached from the particle agglomerator through a first filter.

[0070] In this embodiment, at least two of the aforementioned liquid tanks can be provided; when the cleaning fluid in one of the liquid tanks is supplied to the process chamber, the cleaning fluid in the remaining liquid tanks is preheated and treated to remove charged particles; when the cleaning fluid in one of the liquid tanks reaches its service life during the process of liquid supply, the remaining liquid tanks are switched to continue the process of liquid supply.

[0071] The service life of the cleaning solution in the cleaning solution tank can be set according to the process cycle time of the cleaning solution (i.e., the time it circulates in the process chamber), the number of wafers being cleaned, or the amount of particulate matter in the cleaning solution.

[0072] It should be noted that this specification adopts a progressive approach. The wafer cleaning methods described later focus on the differences between them and the wafer cleaning systems described earlier. For the same or similar parts, please refer to each other.

[0073] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A wafer cleaning system, characterized in that, include: A liquid container is used to hold cleaning fluid; A pre-circulation unit is used to preheat the cleaning solution in the medicine tank; as well as The process liquid supply unit is used to supply the cleaning liquid, which has been treated by the pre-circulation unit, from the liquid tank to the process chamber; The pre-circulation unit includes a particle agglomerator and a first filter. During the preheating process, the cleaning solution circulates between the medicine tank, the first filter, and the particle agglomerator. The particle agglomerator adsorbs charged particles in the cleaning solution and agglomerates them into aggregated particles. The first filter filters out the aggregated particles that have detached from the particle agglomerator.

2. The wafer cleaning system as described in claim 1, characterized in that, The wafer cleaning system includes a first chemical solution tank, a second chemical solution tank, a second valve, and an eighth valve. The B end of the second valve is connected to the first chemical solution tank, the C end of the second valve is connected to the second chemical solution tank, the A end of the second valve is connected to the inlet of the first filter, the outlet of the first filter is connected to the inlet of the particle agglomerator, the outlet of the particle agglomerator is connected to the A end of the eighth valve, the B end of the eighth valve is connected to the first chemical solution tank, and the C end of the eighth valve is connected to the second chemical solution tank.

3. The wafer cleaning system as described in claim 2, characterized in that, The wafer cleaning system includes a third valve and a fourth valve. The B end of the third valve is connected to the first chemical solution tank, the C end of the third valve is connected to the second chemical solution tank, the A end of the third valve is connected to the inlet of the process chamber, the outlet of the process chamber is connected to the A end of the fourth valve, the B end of the fourth valve is connected to the first chemical solution tank, and the C end of the fourth valve is connected to the second chemical solution tank.

4. The wafer cleaning system as described in claim 3, characterized in that, The pre-circulation unit further includes a first heater, the inlet of which is connected to end A of the second valve, and the outlet of which is connected to the inlet of the first filter; the process supply unit includes a second heater and a second filter, the inlet of which is connected to end A of the third valve, the outlet of which is connected to the inlet of the second filter, and the outlet of the second filter is connected to the inlet of the process chamber.

5. The wafer cleaning system as described in claim 1, characterized in that, The colloidal agglomerator includes a reaction plate. The cleaning liquid flowing through the colloidal agglomerator rubs against the reaction plate, causing the reaction plate to become positively charged. Negatively charged colloidal particles in the cleaning liquid are adsorbed on the surface of the reaction plate and agglomerate to form agglomerated colloidal particles.

6. The wafer cleaning system as described in claim 5, characterized in that, The material of the coating on the surface of the reaction plate includes nitrogen-doped silicon carbide, silicon oxide, or silicon nitride.

7. The wafer cleaning system as described in claim 5, characterized in that, The particle agglomerator includes two reaction plates arranged opposite each other, with the edges of the two reaction plates sealed so that the gap between the two reaction plates serves as a flow channel for the cleaning liquid.

8. The wafer cleaning system as described in claim 5, characterized in that, The particle agglomerator also includes a drug inflow pipe, which is parallel to the surface of the reaction plate, and the flow direction of the cleaning liquid through the reaction plate is parallel to the surface of the reaction plate.

9. The wafer cleaning system as described in claim 1, characterized in that, The colloidal agglomerator is tubular, and the inner wall of the colloidal agglomerator has multiple friction particles. The cleaning fluid flowing through the colloidal agglomerator rubs against the friction particles, causing the inner wall of the colloidal agglomerator to become positively charged. The negatively charged colloidal particles in the cleaning fluid are adsorbed onto the inner wall of the colloidal agglomerator and agglomerate to form agglomerated colloidal particles.

10. The wafer cleaning system as described in claim 9, characterized in that, The materials of the friction particles include nitrogen-doped silicon carbide, silicon oxide, or silicon nitride.

11. The wafer cleaning system as described in claim 9, characterized in that, Both ends of the pipeline of the colloid agglomerator are equipped with sieve plates, and the friction particles are disposed between the sieve plates.

12. The wafer cleaning system as described in claim 1, characterized in that, The pre-circulation unit includes a plurality of the colloidal agglomerators, which are connected in parallel in the pre-circulation unit.

13. The wafer cleaning system as described in claim 1, characterized in that, The pre-circulation unit includes an abnormality handling pipeline. One end of the abnormality handling pipeline is connected to the inlet of the colloidal agglomerator and the other end is connected to the outlet of the colloidal agglomerator. The abnormality handling pipeline has a valve. When the colloidal agglomerator is blocked, the valve of the abnormality handling pipeline is opened, and the cleaning fluid can flow directly back to the medicine tank without passing through the colloidal agglomerator.

14. The wafer cleaning system as described in claim 1, characterized in that, The cleaning solution is used to clean the wafers after dry etching.

15. A wafer cleaning method, characterized in that, include: The cleaning solution in the medicine tank is pretreated, and the pretreatment includes preheating treatment and removal of charged particles. The pretreated cleaning solution is supplied to the process chamber; During the preheating process, charged particles in the cleaning solution are adsorbed by a particle agglomerator and agglomerated into aggregated particles. The aggregated particles that have detached from the particle agglomerator are then removed by a first filter.

16. The wafer cleaning method as described in claim 15, characterized in that, At least two of the aforementioned liquid tanks are provided; while the cleaning solution in one of the liquid tanks is supplied to the process chamber, the cleaning solution in the remaining liquid tanks is preheated and treated to remove charged particles.

17. The wafer cleaning method as described in claim 15, characterized in that, At least two of the aforementioned chemical solution tanks are provided; when the cleaning solution in one of the chemical solution tanks reaches its service life during the process of supplying the solution, the remaining chemical solution tanks are switched to continue the process of supplying the solution.

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