Method for improving particle generation between epitaxial cavity and exchange cavity

Abstract

The invention relates to a method for improving particles generated between an epitaxial cavity and an exchange cavity, and the method is characterized in that the method comprises the following stages: S100, in the first stage, removing oxides, raising the temperature in the epitaxial cavity to a preset temperature, and introducing hydrogen to remove the oxides on the surface of silicon; s200, second-stage impurity dissolution: introducing hydrogen chloride gas into the epitaxial cavity to dissolve metal impurities and part of impurities in the cavity; s300, performing third-stage cleaning, filling hydrogen into the epitaxial cavity, performing air exhaust treatment on the epitaxial cavity through a tail gas treatment device, removing reactants and impurities in the cavity, monitoring the pressure in the epitaxial cavity in real time, adjusting the air exhaust rate by using an air pump, ensuring that the pressure in the epitaxial cavity reaches 1.2 times of the pressure of an exchange cavity, preventing particles from migrating, and performing third-stage cleaning; and a gradual heating mode is adopted, so that oxides on the surface of the silicon wafer are completely removed, thermal stress is controlled within a preset range, and particle generation caused by temperature difference is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor manufacturing, and in particular to a method for improving particles generated between an epitaxial cavity and an exchange cavity. Background Art

[0002] In the semiconductor manufacturing process, epitaxial growth is a key step for forming high-quality single crystal layers on silicon wafers. The quality of the epitaxial layer is directly related to the performance and reliability of the final device. However, particles are easily generated between the epitaxial cavity and the exchange cavity. These particles will seriously affect the quality of the epitaxial layer, causing device performance degradation or even failure.

[0003] In the existing technology, some simple purging and exhaust methods are usually used to reduce the generation of particles, but the effects of these methods are limited. However, the existing technology has some problems in this field; for example, Chinese patent CN108624955 B discloses a reaction chamber and epitaxial growth equipment. This technology effectively reduces the reaction by-products attached to the surface of the base and the bottom of the chamber by providing a purge gas in the gap between the base and the bottom of the chamber, thereby reducing the risk of particle contamination. However, this technology does not solve the problem of the pressure difference between the epitaxial chamber and the exchange chamber, resulting in particles in the chamber being blown onto the surface of the silicon wafer before the silicon wafer enters the epitaxial chamber, affecting the epitaxial quality. Summary of the invention

[0004] The present invention aims to solve the problems existing in the above-mentioned prior art and provides an improved method for generating particles between the epitaxial cavity and the exchange cavity. Through multi-stage processing, oxides are effectively removed, impurities are dissolved and the cavity is thoroughly cleaned to ensure the quality of the epitaxial layer.

[0005] The technical solution adopted by the present invention to solve the technical problem is: the improved method for generating particles between the epitaxial cavity and the exchange cavity is characterized by comprising the following stages: S100, the first stage is to remove oxides, raise the temperature in the epitaxial chamber to a preset temperature, and introduce hydrogen to remove oxides on the silicon surface; S200, the second stage of dissolving impurities, introducing hydrogen chloride gas into the epitaxial cavity to dissolve metal impurities and some impurities in the cavity; S300, the third stage of cleaning, is to fill hydrogen into the epitaxial chamber, and to evacuate the epitaxial chamber through an exhaust gas treatment device to remove reactants and impurities in the chamber.

[0006] Preferably, the first stage of removing oxides specifically includes: S110, firstly, the temperature in the epitaxial cavity is raised to a preset temperature, so as to ensure that the epitaxial cavity is stable and uniform, and to avoid particle generation caused by temperature difference; S120, then hydrogen is introduced, and the hydrogen reacts with the silicon oxide on the surface of the silicon wafer at a preset temperature to generate water vapor which evaporates and the oxide layer is removed. At this time, the pressure in the epitaxial chamber after the hydrogen is introduced is 500-700 Torr; S130, after removing the oxide layer, hydrogen is filled into the epitaxial cavity through the tail gas treatment device, the gas flow rate is 60slm, and the purge is performed for 60 seconds.

[0007] Preferably, the preset temperature is in the range of 700-900°C, and during the heating process, the temperature is gradually increased, and each increase of 50°C is kept stable for 5 minutes to ensure that the oxide on the surface of the silicon wafer is completely removed; by controlling the heating rate, the thermal stress is controlled within 10 MPa, and the particle generation amount is controlled to no more than 8 particles per cubic centimeter; Among them, after reaching the preset temperature, the hydrogen flow rate is controlled to 40-60slm to ensure that the hydrogen fully reacts with the oxide layer on the surface of the silicon wafer, and the reaction time is 10-30 minutes.

[0008] Preferably, the second stage of dissolving impurities specifically includes: S210, after the hydrogen reaction, maintaining the temperature in the epitaxial chamber stable, ensuring that the temperature in the epitaxial chamber is stable at 700-900° C.; S220, introducing hydrogen chloride gas into the epitaxial chamber. The hydrogen chloride gas can combine with water vapor, a product of the reaction between hydrogen and silicon oxide in the previous stage, to generate hydrochloric acid, which can dissolve metal particles and some other impurities on the surface of the silicon wafer.

[0009] Preferably, the duration of introducing hydrogen chloride gas is 10-100 s, and the flow rate of hydrogen chloride gas is 50-80 slm.

[0010] Preferably, the third stage cleaning specifically includes: S310, introducing hydrogen into the epitaxial cavity as a cleaning gas; S320, monitoring the pressure in the epitaxial cavity in real time through a pressure sensor and feeding it back to the exhaust pump of the tail gas treatment device, and controlling the pressure of the epitaxial cavity by adjusting the exhaust rate through the exhaust pump, so that the pressure in the epitaxial cavity and the pressure in the exchange cavity are maintained within a preset value; S330, discharging impurities in the epitaxial cavity through a treatment pump of an exhaust gas treatment device; S340, after the epitaxial growth is completed, the cavity is purged for 3 minutes to blow out the small particles remaining in the cavity after the epitaxy from the tail gas pipeline, and in the purging step, the hydrogen flow rate can be adjusted to a high flow rate or a low flow rate; S350. Finally, a particle detection device is used to monitor the particle concentration in the epitaxial cavity to ensure the cleaning effect; Among them, during the entire third stage cleaning process, the pressure in the epitaxial chamber reached 1.2 times the pressure of the exchange chamber.

[0011] Preferably, the ventilation and exhaust operations are carried out in parallel until the end of this stage, and in the step of introducing hydrogen as a cleaning gas in S310, the filling rate of the exhaust gas treatment device is dynamically adjusted by monitoring the pressure change in the epitaxial chamber to maintain the pressure in the epitaxial chamber.

[0012] Preferably, in the third stage cleaning process, the hydrogen purge time is 60-120s, and the hydrogen flow rate is 40-60slm; and in the step of purging the epitaxial cavity in S340, multi-stage purge is performed, first with high flow hydrogen 60slm±5 for 30 seconds, and then with low flow hydrogen 40slm±5 for 30 seconds, to remove small particles in the cavity.

[0013] Preferably, the air pressure of the vacuum pump is greater than the air pressure of the treatment pump, and while the tail gas treatment device is inflating the epitaxial cavity, it is also pumping air through the tail gas pipeline to ensure that the gas flow rate in the epitaxial cavity reaches a preset value; Among them, after the exhaust gas pipeline is opened in S320, the exhaust gas pipeline is kept open for 10 seconds.

[0014] Preferably, after the third stage cleaning, a fourth stage verification is further included, S400, in which a particle detection device is used to detect the number of particles in the epitaxial cavity to ensure that the number of particles in the cavity is lower than a predetermined threshold value to ensure the quality of subsequent epitaxial growth. The fourth phase verification steps specifically include: S410, the particle detection device uses a laser scattering method or an optical microscope method to monitor the particle concentration in the epitaxial cavity; S420, the predetermined threshold is no more than 8 particles per cubic centimeter to ensure the quality of epitaxial growth; S430, if the number of detected particles exceeds a predetermined threshold, triggering an automatic cleaning procedure, including but not limited to passing high-flow hydrogen gas for 60 seconds again, and re-performing the cleaning steps of S300 to S340; S440, after completing the automatic cleaning procedure, re-performing particle detection until the number of particles meets a predetermined threshold; S450, record the data of each inspection and cleaning, generate reports and archive them for subsequent process optimization and quality traceability.

[0015] The present invention has the following beneficial effects: 1. By real-time monitoring of the pressure in the epitaxial chamber and adjusting the pumping rate with a vacuum pump, ensure that the pressure in the epitaxial chamber reaches 1.2 times the pressure of the exchange chamber to prevent particle migration. The temperature is gradually increased to ensure that the oxide on the surface of the silicon wafer is completely removed and the thermal stress is controlled within the preset range to avoid particle generation caused by temperature difference.

[0016] 2. After the epitaxial growth is completed, the cavity is purged for 3 minutes in multiple stages. By dynamically adjusting the inflation rate of the exhaust gas treatment device, the small particles remaining in the cavity are completely removed to ensure the cleaning effect.

[0017] 3. Use advanced particle detection equipment to monitor the particle concentration in the epitaxial cavity to ensure that the number of particles in the cavity after cleaning is lower than the predetermined threshold. If the number of detected particles exceeds the predetermined threshold, the automatic cleaning procedure is triggered, including but not limited to re-introducing high-flow hydrogen purge for 60 seconds and re-executing the cleaning steps from S300 to S340 to ensure that the final product quality meets the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of S100 to S300 in the solution of the present invention; Figure 2 It is a flow chart of S400 in the solution of the present invention; Figure 3 This is a schematic diagram of the results of particle testing after conventional silicon wafer epitaxy; Figure 4 This is a graph showing the results of particle testing on the improved silicon wafer after epitaxy according to the present invention. DETAILED DESCRIPTION

[0019] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0020] like Figures 1 to 4 As shown, a method for improving the generation of particles between an epitaxial chamber and an exchange chamber is characterized in that it includes the following stages: S100, the first stage is to remove oxides, increase the temperature in the epitaxial chamber to a preset temperature, and introduce hydrogen to remove oxides on the silicon surface; S200, the second stage is to dissolve impurities, introduce hydrogen chloride gas into the epitaxial chamber to dissolve metal impurities and some impurities in the chamber; S300, the third stage is to clean, fill hydrogen into the epitaxial chamber, and evacuate the epitaxial chamber through an exhaust gas treatment device to remove reactants and impurities in the chamber.

[0021] First, in the first stage of oxide removal, the temperature in the epitaxial chamber is raised to a preset temperature and hydrogen is introduced to ensure that the oxide on the silicon surface is effectively removed; second, when dissolving impurities in the second stage, hydrogen chloride gas is introduced into the epitaxial chamber to use its chemical properties to dissolve metal impurities and some other impurities in the chamber; finally, in the third stage of cleaning, hydrogen is filled into the epitaxial chamber and the epitaxial chamber is evacuated through the exhaust gas treatment device to solve the pressure difference between the epitaxial chamber and the exchange chamber and completely remove the reactants and impurities in the chamber. The entire process precisely controls the operating parameters of each stage to ensure the cleanliness of the epitaxial chamber and significantly reduce the generation of particles, thereby improving the quality of the epitaxial layer and the performance of semiconductor devices.

[0022] Specifically, the first stage of removing oxides includes: S110, firstly heating the epitaxial chamber to make the chamber reach a preset temperature to ensure stability and uniformity in the epitaxial chamber and avoid particle generation due to temperature difference; S120, then introducing hydrogen, which reacts with silicon oxide on the surface of the silicon wafer at a preset temperature to generate water vapor that evaporates, and the oxide layer is removed. At this time, the pressure in the epitaxial chamber after the introduction of hydrogen is 500-700Torr; S130, after removing the oxide layer, hydrogen is filled into the epitaxial chamber through the exhaust gas treatment device, the gas flow rate is 60 slm, and purged for 60 seconds.

[0023] In the first stage of oxide removal, the temperature in the epitaxial chamber is first raised S110 to gradually raise the temperature in the chamber to a preset temperature and keep it stable and uniform to avoid particle generation caused by temperature difference; then, hydrogen is introduced S120, and the hydrogen reacts with the silicon oxide on the surface of the silicon wafer at a preset temperature to generate water vapor and evaporate, thereby effectively removing the oxide layer. At this time, the pressure in the epitaxial chamber is maintained at 500-700 Torr; finally, after removing the oxide layer, hydrogen is filled into the epitaxial chamber through the exhaust gas treatment device, with a gas flow rate of 60 slm, and a 60-second purge S130 is performed to ensure that the reaction products remaining in the chamber are completely removed.

[0024] Furthermore, the preset temperature range is 700-900°C, and during the heating process, a gradual heating method is adopted, and each increase of 50°C is maintained stable for 5 minutes to ensure that the oxide on the surface of the silicon wafer is completely removed; by controlling the heating rate, the thermal stress is controlled within 10 MPa, and the particle generation amount is controlled to no more than 8 particles per cubic centimeter; wherein, after reaching the preset temperature, the hydrogen flow rate is controlled to 40-60slm to ensure that the hydrogen fully reacts with the oxide layer on the surface of the silicon wafer, and the reaction time is 10-30 minutes.

[0025] In the first stage of oxide removal, the temperature in the epitaxial chamber is gradually increased S110 to gradually increase the temperature in the chamber to a preset temperature range of 700-900°C. During the temperature increase, the temperature is gradually increased, and the temperature is kept stable for 5 minutes every 50°C increase to ensure that the oxide on the surface of the silicon wafer is completely removed and to avoid particle generation caused by temperature difference. The thermal stress is controlled within 10 MPa by accurately controlling the heating rate, and the particle generation is controlled to be no more than 8 particles per cubic centimeter. After reaching the preset temperature, hydrogen is introduced S120, and the hydrogen flow rate is controlled within the range of 40-60 slm to ensure that the hydrogen fully reacts with the oxide layer on the surface of the silicon wafer. The reaction time is set to 10-30 minutes. Under this condition, the hydrogen reacts with the silicon oxide on the surface of the silicon wafer at the preset temperature to generate water vapor and volatilize it, thereby effectively removing the oxide layer. At this time, the pressure in the epitaxial chamber is maintained at 500-700 Torr. Finally, after removing the oxide layer, hydrogen is filled into the epitaxial chamber through the tail gas treatment device, and the gas flow rate is 60 slm, and perform a 60-second purge S130 to ensure that the residual reaction products in the chamber are completely removed, further improving the cleaning effect.

[0026] Specifically, the second stage of dissolving impurities includes: S210, after the hydrogen reaction, maintaining the temperature in the epitaxial chamber stable, ensuring that the temperature in the epitaxial chamber is stable at 700-900°C; S220, introducing hydrogen chloride gas into the epitaxial chamber, the hydrogen chloride gas can combine with the water vapor produced by the reaction of hydrogen and silicon oxide in the previous stage to generate hydrochloric acid, which can dissolve metal particles and some other impurities on the surface of the silicon wafer.

[0027] In the second stage of dissolving impurities, first, after the hydrogen reaction, the temperature in the epitaxial chamber is kept stable S210 to ensure that the temperature in the epitaxial chamber is maintained in the range of 700-900°C. This stable temperature environment provides ideal conditions for subsequent chemical reactions and avoids adverse effects caused by temperature fluctuations. Subsequently, hydrogen chloride gas is introduced into the epitaxial chamber S220. The hydrogen chloride gas can combine with the water vapor generated after the reaction of hydrogen and silicon oxide in the previous stage to form hydrochloric acid. The generated hydrochloric acid can effectively dissolve the metal particles and some other impurities on the surface of the silicon wafer, thereby further purifying the surface of the silicon wafer and reducing potential sources of particle pollution. In this way, the effective removal of impurities in the cavity is ensured, providing a cleaner environment for subsequent epitaxial growth.

[0028] Furthermore, the duration of introducing the hydrogen chloride gas is 10-100 s, and the flow rate of the hydrogen chloride gas is 50-80 slm.

[0029] The hydrogen chloride gas can combine with the water vapor generated after the reaction of hydrogen and silicon oxide in the previous stage to form hydrochloric acid. The generated hydrochloric acid can effectively dissolve the metal particles and some other impurities on the surface of the silicon wafer, thereby further purifying the surface of the silicon wafer and reducing potential particle pollution sources. In this embodiment, in order to ensure the best dissolution effect, the duration of the introduction of hydrogen chloride gas is 10-100 seconds, and the flow rate is controlled within the range of 50-80 slm. By accurately controlling the introduction time and flow rate, it is ensured that the hydrogen chloride gas fully contacts and reacts with the reaction product, thereby achieving effective removal of impurities in the cavity and providing a cleaner environment for subsequent epitaxial growth.

[0030] Specifically, the third stage cleaning includes: S310, introducing hydrogen into the epitaxial chamber as a cleaning gas; S320, monitoring the pressure in the epitaxial chamber in real time through a pressure sensor and feeding it back to the vacuum pump of the exhaust gas treatment device, and using the vacuum pump to adjust the vacuum rate to control the pressure of the epitaxial chamber, so that the pressure in the epitaxial chamber and the pressure in the exchange chamber are maintained within a preset value; S330, discharging the impurities in the epitaxial chamber through the treatment pump of the exhaust gas treatment device; S340, after the epitaxial growth is completed, the cavity is purged for 3 minutes alone to blow out the small particles remaining in the cavity after the epitaxy from the exhaust gas pipe, and in the purging step, the hydrogen flow rate can be adjusted to high flow or low flow; S350, finally, using a particle detection device to monitor the particle concentration in the epitaxial chamber to ensure the cleaning effect; wherein, during the entire third stage cleaning process, the pressure in the epitaxial chamber reaches 1.2 times the pressure of the exchange chamber.

[0031] In the third stage cleaning process, hydrogen is first introduced into the epitaxial chamber as a cleaning gas S310. Subsequently, the pressure in the epitaxial chamber is monitored in real time by a pressure sensor, and the data is fed back to the vacuum pump of the exhaust gas treatment device S320. The vacuum pump is used to adjust the vacuum rate to accurately control the pressure of the epitaxial chamber to ensure that it and the pressure of the exchange chamber remain within the preset value. During the entire cleaning process, the pressure in the epitaxial chamber is maintained at 1.2 times the pressure of the exchange chamber to prevent particles from migrating from the exchange chamber to the epitaxial chamber. Next, the impurities in the epitaxial chamber are discharged through the treatment pump of the exhaust gas treatment device S330 to ensure that there are no residual reactants and impurities in the chamber. After the epitaxial growth is completed, the chamber is purged for 3 minutes alone S340 to completely blow out the small particles remaining in the chamber after the epitaxy from the exhaust gas pipe. During the purging step, the hydrogen flow rate can be adjusted to a high flow rate of 60 slm±5 or a low flow rate of 40 slm±5 as needed to ensure the cleaning effect at different stages; finally, a particle detection device is used to monitor the particle concentration S350 in the epitaxial cavity to ensure that the cleaning effect meets the predetermined standard. Through these measures, the present invention effectively removes small particles in the cavity and significantly improves the quality of the epitaxial layer and the performance of the semiconductor device.

[0032] Furthermore, ventilation and exhaust operations are performed in parallel until the end of this stage, and in the step of introducing hydrogen as a cleaning gas in S310, the filling rate of the exhaust gas treatment device is dynamically adjusted by monitoring the pressure change in the epitaxial chamber to maintain the pressure in the epitaxial chamber.

[0033] In the third stage of the cleaning process, ventilation and exhaust operations are carried out in parallel until the end of this stage. Specifically, in the step of introducing hydrogen as a cleaning gas in S310, the pressure change in the epitaxial chamber is monitored in real time by a pressure sensor, and the data is fed back to the exhaust gas treatment device. According to the monitored pressure changes, the inflation rate of the exhaust gas treatment device is dynamically adjusted to ensure that the pressure in the epitaxial chamber is maintained within a preset value. In particular, during the entire cleaning process, the pressure in the epitaxial chamber is maintained at 1.2 times the pressure of the exchange chamber. This precise pressure control ensures the effectiveness and stability of the cleaning process and avoids particle generation or migration problems caused by pressure fluctuations.

[0034] Furthermore, in the third stage cleaning process, the hydrogen purge time is 60-120s, and the hydrogen flow rate is 40-60slm; and in the step of purging the epitaxial chamber in S340, multi-stage purge is performed, first with high flow hydrogen 60slm±5 for 30 seconds, and then with low flow hydrogen 40slm±5 for 30 seconds, to remove small particles in the chamber.

[0035] In the third stage of cleaning, the hydrogen purge time is 60-120 seconds, and the hydrogen flow rate is controlled within the range of 40-60 slm. In particular, in the step of purging the epitaxial chamber in S340, a multi-stage purge strategy is adopted: first, a high flow rate of hydrogen 60 slm±5 is used for 30 seconds, and then a low flow rate of hydrogen 40 slm±5 is used for another 30 seconds. This multi-stage purge method can more effectively remove small particles remaining in the chamber and ensure that the cleanliness of the epitaxial chamber reaches the best state.

[0036] It is worth mentioning that, as shown in Table 1 below, in this embodiment, the hydrogen flow rate is controlled within the range of 40-60 slm, the hydrogen purge flow rate is 40 slm, and when the flow rate reaches 60 slm, the number of small particles 120 nm remaining in the cavity is significantly reduced, and the hydrogen purge flow rate is 60 slm, and the best flow rate is reached when the flow rate reaches 60 slm.

[0037] Table 1 The following Table 2 shows the difference more clearly and intuitively. The small particles (120nm particles) in the cavity are effectively removed, which significantly improves the quality of the epitaxial layer and the performance of the semiconductor device.

[0038] Table 2 Furthermore, the air pressure of the vacuum pump is greater than the air pressure of the treatment pump, and while the exhaust gas treatment device inflates the epitaxial cavity, it extracts air through the exhaust gas pipe to ensure that the gas flow rate in the epitaxial cavity reaches a preset value; wherein, after the exhaust gas pipe is opened in S320, the exhaust gas pipe is kept open for 10 seconds.

[0039] In the third stage of cleaning, the air pressure of the vacuum pump is set to be greater than the air pressure of the treatment pump to ensure effective gas flow and impurity discharge. Specifically, in S320, the pressure in the epitaxial chamber is monitored in real time by a pressure sensor, and the data is fed back to the vacuum pump of the exhaust gas treatment device. In this process, the exhaust gas treatment device inflates the epitaxial chamber while exhausting air through the exhaust pipe to ensure that the gas flow rate in the epitaxial chamber reaches the preset value; in order to achieve this goal, after opening the exhaust pipe, the exhaust pipe is kept open for 10 seconds to ensure that the gas flow rate is stable and the pressure in the epitaxial chamber is maintained within a preset range. This precise air pressure and gas flow rate control measure effectively prevents the migration and residue of particles and improves the cleaning effect.

[0040] Furthermore, after the third stage cleaning, it also includes a S400, fourth stage verification, using a particle detection device to detect the number of particles in the epitaxial cavity to ensure that the number of particles in the cavity is lower than a predetermined threshold to ensure the quality of subsequent epitaxial growth, wherein the fourth stage verification steps specifically include: S410, the particle detection device uses a laser scattering method or an optical microscopy method to monitor the particle concentration in the epitaxial cavity; S420, the predetermined threshold is no more than 8 particles per cubic centimeter to ensure the quality of epitaxial growth; S430, if the number of detected particles exceeds the predetermined threshold, triggering an automatic cleaning procedure, including but not limited to re-introducing a high-flow hydrogen purge for 60 seconds, and re-executing the cleaning steps of S300 to S340; S440, after completing the automatic cleaning procedure, re-perform particle detection until the number of particles meets the predetermined threshold; S450, recording the data of each detection and cleaning, generating a report and archiving it for subsequent process optimization and quality traceability.

[0041] After the third stage cleaning, a fourth stage verification S400 is also included to ensure that the number of particles in the epitaxial cavity is lower than a predetermined threshold value, so as to ensure the quality of subsequent epitaxial growth. Specifically, a particle detection device is used to detect the number of particles in the epitaxial cavity. The device adopts a laser scattering method or an optical microscopy method S410 to monitor the particle concentration in the epitaxial cavity. The predetermined threshold value is set to no more than 8 particles per cubic centimeter S420 to ensure the quality of epitaxial growth. If the number of detected particles exceeds the predetermined threshold value, an automatic cleaning procedure S430 is triggered, including but not limited to re-introducing a high-flow hydrogen purge for 60 seconds and re-executing the cleaning steps S300 to S340 until the number of particles meets the requirements. After completing the automatic cleaning procedure, the particle detection S440 is re-performed to ensure that the number of particles finally meets the predetermined threshold value; in addition, the data of each detection and cleaning is recorded, and a report is generated and archived S450 for subsequent process optimization and quality traceability.

[0042] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed as above in the form of preferred embodiments, it is not intended to limit the present invention. Any technical personnel in the field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for improving the generation of particles between an epitaxial cavity and an exchange cavity, characterized in that: The following phases are included: S100, the first stage is to remove oxides, raise the temperature in the epitaxial chamber to a preset temperature, and introduce hydrogen to remove oxides on the silicon surface; S200, the second stage of dissolving impurities, introducing hydrogen chloride gas into the epitaxial cavity to dissolve metal impurities and some impurities in the cavity; S300, the third stage of cleaning, is to fill hydrogen into the epitaxial chamber, and to evacuate the epitaxial chamber through an exhaust gas treatment device to remove reactants and impurities in the chamber.

2. The method for improving the generation of particles between an epitaxial cavity and an exchange cavity according to claim 1, characterized in that: The first stage of removing oxides specifically includes: S110, firstly, the temperature in the epitaxial cavity is raised to a preset temperature, so as to ensure that the epitaxial cavity is stable and uniform, and to avoid particle generation caused by temperature difference; S120, then hydrogen is introduced, and the hydrogen reacts with the silicon oxide on the surface of the silicon wafer at a preset temperature to generate water vapor which evaporates and the oxide layer is removed. At this time, the pressure in the epitaxial chamber after the hydrogen is introduced is 500-700 Torr; S130, after removing the oxide layer, hydrogen is filled into the epitaxial cavity through the tail gas treatment device, the gas flow rate is 60 slm, and the purge is performed for 60 seconds.

3. The method for improving the generation of particles between an epitaxial cavity and an exchange cavity according to claim 2, characterized in that: The preset temperature range is 700-900°C, and during the heating process, the temperature is gradually increased, and each increase of 50°C is kept stable for 5 minutes to ensure that the oxide on the surface of the silicon wafer is completely removed; by controlling the heating rate, the thermal stress is controlled within 10MPa, and the particle generation amount is controlled to no more than 8 particles per cubic centimeter; Among them, after reaching the preset temperature, the hydrogen flow rate is controlled to 40-60slm to ensure that the hydrogen fully reacts with the oxide layer on the surface of the silicon wafer, and the reaction time is 10-30 minutes.

4. The method for improving the generation of particles between an epitaxial cavity and an exchange cavity according to claim 1, characterized in that: The second stage of dissolving impurities specifically includes: S210, after the hydrogen reaction, maintaining the temperature in the epitaxial chamber stable, ensuring that the temperature in the epitaxial chamber is stable at 700-900° C.; S220, introducing hydrogen chloride gas into the epitaxial chamber. The hydrogen chloride gas can combine with water vapor, a product of the reaction between hydrogen and silicon oxide in the previous stage, to generate hydrochloric acid, which can dissolve metal particles and some other impurities on the surface of the silicon wafer.

5. The method for improving the generation of particles between an epitaxial cavity and an exchange cavity according to claim 4, characterized in that: The duration of introducing hydrogen chloride gas is 10-100s, and the flow rate of hydrogen chloride gas is 50-80slm.

6. The improved method for generating particles between an epitaxial cavity and an exchange cavity according to claim 1, characterized in that: The third stage of cleaning specifically includes: S310, introducing hydrogen into the epitaxial cavity as a cleaning gas; S320, monitoring the pressure in the epitaxial cavity in real time through a pressure sensor and feeding it back to the exhaust pump of the tail gas treatment device, and controlling the pressure of the epitaxial cavity by adjusting the exhaust rate through the exhaust pump, so that the pressure in the epitaxial cavity and the pressure in the exchange cavity are maintained within a preset value; S330, discharging impurities in the epitaxial cavity through a treatment pump of an exhaust gas treatment device; S340, after the epitaxial growth is completed, the cavity is purged for 3 minutes to blow out the small particles remaining in the cavity after the epitaxy from the tail gas pipeline, and in the purging step, the hydrogen flow rate can be adjusted to a high flow rate or a low flow rate; S350. Finally, a particle detection device is used to monitor the particle concentration in the epitaxial cavity to ensure the cleaning effect; Among them, during the entire third stage cleaning process, the pressure in the epitaxial chamber reached 1.2 times the pressure of the exchange chamber.

7. A method for improving the generation of particles between an epitaxial cavity and an exchange cavity according to claim 6, characterized in that: The ventilation and exhaust operations are performed in parallel until the end of this stage, and in the step of introducing hydrogen as a cleaning gas in S310, the filling rate of the tail gas treatment device is dynamically adjusted by monitoring the pressure change in the epitaxial chamber to maintain the pressure in the epitaxial chamber.

8. The method for improving the generation of particles between an epitaxial cavity and an exchange cavity according to claim 6, characterized in that: In the third stage cleaning process, the hydrogen purge time is 60-120s, and the hydrogen flow rate is 40-60slm; and in the step of purging the epitaxial cavity in S340, multi-stage purge is performed, first with high flow hydrogen 60slm±5 for 30 seconds, and then with low flow hydrogen 40slm±5 for 30 seconds, to remove small particles in the cavity.

9. A method for improving the generation of particles between an epitaxial cavity and an exchange cavity according to claim 6, characterized in that: The air pressure of the vacuum pump is greater than the air pressure of the treatment pump, and the tail gas treatment device inflates the epitaxial cavity while pumping air through the tail gas pipeline to ensure that the gas flow rate in the epitaxial cavity reaches a preset value; Among them, after the exhaust gas pipeline is opened in S320, the exhaust gas pipeline is kept open for 10 seconds.

10. A method for improving the generation of particles between an epitaxial cavity and an exchange cavity according to claim 6, characterized in that After the third stage of cleaning, there is also a fourth stage of verification, S400, in which a particle detection device is used to detect the number of particles in the epitaxial chamber to ensure that the number of particles in the chamber is lower than a predetermined threshold value to ensure the quality of subsequent epitaxial growth. The fourth phase verification steps specifically include: S410, the particle detection device uses a laser scattering method or an optical microscope method to monitor the particle concentration in the epitaxial cavity; S420, the predetermined threshold is no more than 8 particles per cubic centimeter to ensure the quality of epitaxial growth; S430, if the number of detected particles exceeds a predetermined threshold, triggering an automatic cleaning procedure, including but not limited to passing high-flow hydrogen gas for 60 seconds again, and re-performing the cleaning steps of S300 to S340; S440, after completing the automatic cleaning procedure, re-performing particle detection until the number of particles meets a predetermined threshold; S450, record the data of each inspection and cleaning, generate reports and archive them for subsequent process optimization and quality traceability.

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