Improved method of generating particles between epitaxial and exchange cavities

Abstract

The application relates to an improved method for generating particles between an epitaxial cavity and an exchange cavity, characterized by comprising the following stages: S100, a first stage of removing oxide, increasing the temperature in the epitaxial cavity to a preset temperature, and inputting hydrogen to remove silicon surface oxide; S200, a second stage of dissolving impurities, inputting hydrogen chloride gas into the epitaxial cavity to dissolve metal impurities and part of impurities in the cavity; S300, a third stage of cleaning, filling hydrogen into the epitaxial cavity, and performing exhaust treatment on the epitaxial cavity through an exhaust treatment device to remove reactants and impurities in the cavity, through real-time monitoring of the pressure in the epitaxial cavity and adjusting the exhaust rate by using an exhaust pump, the pressure in the epitaxial cavity is ensured to reach 1.2 times of the pressure of the exchange cavity, particle migration is prevented, and a step-by-step heating mode is adopted to ensure that the silicon wafer surface oxide is completely removed and the thermal stress is controlled within a preset range to avoid particle generation caused by temperature difference.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a method for improving the generation of particles between an epitaxial cavity and a switching cavity. BACKGROUND

[0002] In the semiconductor manufacturing process, epitaxial growth is a key step for forming a high-quality single crystal layer on a silicon wafer; 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 switching cavity, which can seriously affect the quality of the epitaxial layer and cause device performance degradation or even failure.

[0003] In the existing technology, some simple purging and pumping methods are usually used to reduce the generation of particles, but the effect of these methods is limited, however, there are some problems in the existing technology in this field; for example, Chinese patent CN108624955B discloses a reaction chamber and an epitaxial growth device, which effectively reduces the reaction by-products attached to the surface of the base and the bottom parts of the cavity by providing purging gas in the gap between the base and the bottom of the cavity, and reduces the risk of particle contamination, but this technology does not solve the problem of pressure difference between the epitaxial cavity and the switching cavity, which causes the particles in the cavity to be blown to the surface of the silicon wafer before the silicon wafer enters the epitaxial cavity, affecting the quality of the epitaxial layer. SUMMARY

[0004] The present application solves the above-mentioned problems existing in the prior art, and provides a method for improving the generation of particles between an epitaxial cavity and a switching cavity, which effectively removes oxides, dissolves impurities and thoroughly cleans the cavity through multi-stage processing, ensuring the quality of the epitaxial layer.

[0005] The technical solution adopted by the present application to solve its technical problems: this method for improving the generation of particles between an epitaxial cavity and a switching cavity, characterized by comprising the following stages:

[0006] S100, the first stage removes oxides, the temperature in the epitaxial cavity is raised to a preset temperature, and hydrogen gas is introduced to remove silicon surface oxides;

[0007] S200, the second stage dissolves impurities, hydrogen chloride gas is introduced into the epitaxial cavity to dissolve metal impurities and part of the impurities in the cavity;

[0008] S300, the third stage of cleaning, hydrogen is filled into the epitaxial cavity, and the exhaust treatment device is used to pump the epitaxial cavity to remove the reactants and impurities in the cavity.

[0009] Preferably, the first stage of removing oxides specifically includes:

[0010] S110, first, the epitaxial cavity is heated to a preset temperature to ensure stable and uniform temperature in the epitaxial cavity and avoid particle generation caused by temperature difference;

[0011] S120, then, hydrogen is introduced and reacts with silicon oxide on the surface of the silicon wafer at the preset temperature to generate water vapor which is volatilized, and the oxide layer is removed. The pressure in the epitaxial cavity after the introduction of hydrogen is 500-700 Torr.

[0012] S130, after the removal of the oxide layer, hydrogen is introduced into the epitaxial cavity through the exhaust treatment device, and the gas flow is 60 slm and the purging time is 60 seconds.

[0013] Preferably, the preset temperature ranges from 700-900℃, and during the heating process, a step-by-step heating method is adopted, i.e., the temperature is increased by 50℃ and kept stable for 5 minutes, to ensure complete removal of the surface oxide of the silicon wafer. By controlling the heating rate, the thermal stress is controlled within 10 MPa, and the particle generation is controlled to be no more than 8 particles per cubic centimeter.

[0014] After reaching the preset temperature, the hydrogen flow is controlled to be 40-60 slm to ensure sufficient reaction of hydrogen with the oxide layer on the surface of the silicon wafer, and the reaction time is 10-30 minutes.

[0015] Preferably, the second stage of dissolving impurities specifically includes:

[0016] S210, after the hydrogen reaction, the temperature in the epitaxial cavity is kept stable to ensure that the temperature in the epitaxial cavity is stable at 700-900℃.

[0017] S220, hydrogen chloride gas is introduced into the epitaxial cavity, which can combine with the water vapor produced after the reaction of hydrogen and silicon oxide in the previous stage to generate hydrochloric acid, which can dissolve metal particles and part of other impurities on the surface of the silicon wafer.

[0018] Preferably, the duration of introducing hydrogen chloride gas is 10-100s, and the flow of hydrogen chloride gas is 50-80 slm.

[0019] Preferably, the third stage of cleaning specifically includes:

[0020] S310, hydrogen is introduced into the epitaxial cavity as a cleaning gas;

[0021] S320, the pressure in the epitaxial cavity is monitored in real time by a pressure sensor and fed back to the exhaust pump of the exhaust treatment device, and the exhaust pump is used to adjust the exhaust rate to control the pressure in the epitaxial cavity, so that the pressure in the epitaxial cavity and the pressure in the exchange cavity are kept within the preset value.

[0022] S330, the impurities in the epitaxial cavity are discharged through the treatment pump of the exhaust treatment device.

[0023] S340, after the end of the epitaxial growth, the cavity is purged for 3 minutes alone, the small particles remaining in the post-epitaxial cavity are blown out from the exhaust pipeline, and during the purging step, the hydrogen flow rate can be adjusted to a high flow rate or a low flow rate;

[0024] S350, finally, the particle detection device is used to monitor the particle concentration in the epitaxial cavity to ensure the cleaning effect;

[0025] During the entire third stage cleaning process, the pressure in the epitaxial cavity reaches 1.2 times the pressure of the exchange cavity.

[0026] Preferably, the aeration and air extraction operation is carried out in parallel until the end of this stage, and in the step of introducing hydrogen as a cleaning gas in S310, the air charging rate of the exhaust treatment device is dynamically adjusted by monitoring the pressure change in the epitaxial cavity to maintain the pressure in the epitaxial cavity.

[0027] Preferably, during the third stage cleaning process, the purging time of the hydrogen gas is 60-120s, and the flow rate of the hydrogen gas is 40-60slm; and in the step of purging the epitaxial cavity in S340, small particles in the cavity are removed by multi-stage purging, first purging with high flow rate hydrogen 60slm±5 for 30 seconds, and then purging with low flow rate hydrogen 40slm±5 for 30 seconds.

[0028] Preferably, the air pressure of the air extraction pump is greater than the air pressure of the treatment pump, and the exhaust treatment device charges air into the epitaxial cavity while extracting air through the exhaust pipeline to ensure that the gas flow rate in the epitaxial cavity reaches a preset value;

[0029] Wherein, after opening the exhaust pipeline in S320, the exhaust pipeline is kept open for 10 seconds.

[0030] Preferably, after the third stage cleaning, a fourth stage verification S400 is further included, which uses 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 below a predetermined threshold to ensure the quality of subsequent epitaxial growth,

[0031] The fourth stage verification step specifically includes:

[0032] S410, the particle detection device uses a laser scattering method or an optical microscope method to monitor the particle concentration in the epitaxial cavity;

[0033] S420, the predetermined threshold is no more than 8 particles per cubic centimeter to ensure the quality of epitaxial growth;

[0034] S430, if the detected particle number exceeds the predetermined threshold, trigger the automatic cleaning program, including but not limited to re-passing high-flow hydrogen purge for 60 seconds, and re-executing the cleaning steps of S300 to S340;

[0035] S440, after completing the automatic cleaning program, re-detecting particles until the particle number meets the predetermined threshold;

[0036] S450, record the data of each detection and cleaning, generate a report and archive it for subsequent process optimization and quality traceability.

[0037] The present application has the following beneficial effects:

[0038] 1. By monitoring the pressure in the epitaxial cavity in real time and adjusting the pumping rate with the exhaust pump, the pressure in the epitaxial cavity is ensured to reach 1.2 times the exchange cavity pressure, preventing particle migration, and using a step-by-step heating method, ensuring that the silicon wafer surface oxide is completely removed, and the thermal stress is controlled within a preset range to avoid particle generation caused by temperature difference.

[0039] 2. After epitaxial growth is completed, the cavity is separately purged for 3 minutes, the gas filling rate of the exhaust treatment device is dynamically adjusted, and small particles remaining in the cavity are completely removed to ensure cleaning effect.

[0040] 3. Advanced particle detection equipment is used to monitor the particle concentration in the epitaxial cavity, ensuring that the particle number in the cleaned cavity is below the predetermined threshold, if the detected particle number exceeds the predetermined threshold, trigger the automatic cleaning program, including but not limited to re-passing high-flow hydrogen purge for 60 seconds, and re-executing the cleaning steps of S300 to S340, to ensure that the final product quality meets the requirements. BRIEF DESCRIPTION OF DRAWINGS

[0041] Fig. 1 is the flowchart of S100 to S300 in the scheme of the present application;

[0042] Fig. 2 is the flowchart of S400 in the scheme of the present application;

[0043] Fig. 3 is a schematic diagram of the results of particle testing after conventional silicon wafer epitaxy;

[0044] Fig. 4 is a results diagram of particle testing after silicon wafer epitaxy after improvement. DETAILED DESCRIPTION

[0045] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific embodiments, structures, features and effects according to the present application are described in detail as follows in combination with the drawings and preferred embodiments.

[0046] As shown in Figs. 1 to 4 An improved method for generating particles between an epitaxial chamber and a switching chamber, characterized by comprising the following stages: S100, a first stage of removing oxide, increasing the temperature in the epitaxial chamber to a preset temperature, and introducing hydrogen to remove silicon surface oxide; S200, a second stage of dissolving impurities, introducing hydrogen chloride gas into the epitaxial chamber to dissolve metal impurities and part of other impurities in the chamber; S300, a third stage of cleaning, filling hydrogen into the epitaxial chamber, and performing gas extraction treatment on the epitaxial chamber through a tail gas treatment device to remove reactants and impurities in the chamber.

[0047] Firstly, in the first stage of removing oxide, the temperature in the epitaxial chamber is increased to a preset temperature, and hydrogen is introduced to ensure that the silicon surface oxide is effectively removed; secondly, in the second stage of dissolving impurities, hydrogen chloride gas is introduced into the epitaxial chamber to dissolve metal impurities and part of other impurities in the chamber by utilizing its chemical properties; finally, in the third stage of cleaning, hydrogen is filled into the epitaxial chamber, and gas extraction treatment is performed on the epitaxial chamber through a tail gas treatment device to solve the pressure difference between the epitaxial chamber and the switching chamber, completely remove the reactants and impurities in the chamber, and accurately control 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.

[0048] Specifically, the first stage of removing oxide specifically includes: S110, first performing temperature rising treatment on the epitaxial chamber to make the chamber reach a preset temperature, to ensure that the epitaxial chamber is stable and uniform, and avoid particle generation caused by temperature difference; S120, then introducing hydrogen, which reacts with silicon oxide on the surface of the silicon wafer at the preset temperature to generate water vapor that is volatilized away, and the oxide layer is removed, at this time the pressure in the epitaxial chamber after the introduction of hydrogen is 500-700 Torr; S130, after removing the oxide layer, hydrogen is filled into the epitaxial chamber through a tail gas treatment device, with a gas flow rate of 60 slm, and purging for 60 seconds.

[0049] In the first stage of removing oxide, first, the temperature rising treatment S110 is performed on the epitaxial chamber to gradually increase 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, which reacts with silicon oxide on the surface of the silicon wafer at the preset temperature to generate water vapor that is volatilized away, 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 a tail gas treatment device, with a gas flow rate of 60 slm, and purging for 60 seconds S130, to ensure that the residual reaction products in the chamber are completely removed.

[0050] Further, the preset temperature range is 700-900℃, and in the process of temperature rising, the temperature is raised step by step, and each time the temperature is raised by 50℃, the temperature is kept stable for 5 minutes to ensure that the silicon wafer surface oxide is completely removed; by controlling the temperature rising rate, the thermal stress is controlled within 10 MPa, and at the same time, the particle generation amount is controlled to be not more than 8 particles per cubic centimeter; wherein, after reaching the preset temperature, the hydrogen flow is controlled to be 40-60 slm to ensure that the hydrogen and the silicon wafer surface oxide layer fully react, and the reaction time is 10-30 minutes.

[0051] In the first stage of removing the oxide, the epitaxial cavity is first subjected to a step-by-step temperature rising process S110, so that the temperature in the cavity is gradually raised to a preset temperature range of 700-900℃; in the process of temperature rising, the temperature is raised step by step, and each time the temperature is raised by 50℃, the temperature is kept stable for 5 minutes to ensure that the silicon wafer surface oxide is completely removed, and the generation of particles caused by temperature difference is avoided; by precisely controlling the temperature rising rate, the thermal stress is controlled within 10 MPa, and at the same time, the particle generation amount is controlled to be not more than 8 particles per cubic centimeter; after reaching the preset temperature, hydrogen is introduced S120, and the hydrogen flow is controlled to be in the range of 40-60 slm to ensure that the hydrogen and the silicon wafer surface oxide layer fully react, and 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, thereby effectively removing the oxide layer; at this time, the pressure in the epitaxial cavity is maintained at 500-700 Torr; finally, after removing the oxide layer, hydrogen is filled into the epitaxial cavity through the exhaust treatment device, the gas flow is 60 slm, and the blowing S130 is performed for 60 seconds to ensure that the residual reaction products in the cavity are completely removed, thereby further improving the cleaning effect.

[0052] Specifically, the second stage of dissolving impurities specifically includes: S210, after the hydrogen reaction, the temperature in the epitaxial cavity is kept stable to ensure that the temperature in the epitaxial cavity is stable at 700-900℃; S220, hydrogen chloride gas is introduced into the epitaxial cavity, the hydrogen chloride gas can combine with the water vapor generated after the hydrogen and the silicon oxide react in the previous stage to generate hydrochloric acid, and the hydrochloric acid can dissolve the metal particles and part of other impurities on the surface of the silicon wafer.

[0053] In the second stage of dissolving impurities, first, after the hydrogen reaction, the temperature in the epitaxial cavity is kept stable S210, ensuring that the temperature in the epitaxial cavity is maintained in the range of 700-900℃, and this stable temperature environment provides an ideal condition for the subsequent chemical reaction, avoiding the adverse effects caused by temperature fluctuations. Then, hydrogen chloride gas is introduced into the epitaxial cavity S220. The hydrogen chloride gas can combine with the water vapor generated after the hydrogen and silicon oxide react in the previous stage to form hydrochloric acid. The generated hydrochloric acid can effectively dissolve the metal particles and part of other impurities on the surface of the silicon wafer, further purifying the surface of the silicon wafer and reducing potential particle contamination sources. In this way, the effective removal of impurities in the cavity is ensured, providing a cleaner environment for subsequent epitaxial growth.

[0054] Further, the duration of introducing hydrogen chloride gas is 10-100s, and the flow rate of hydrogen chloride gas is 50-80slm.

[0055] The hydrogen chloride gas can combine with the water vapor generated after the hydrogen and silicon oxide react in the previous stage to form hydrochloric acid. The generated hydrochloric acid can effectively dissolve the metal particles and part of other impurities on the surface of the silicon wafer, further purifying the surface of the silicon wafer and reducing potential particle contamination sources. In this embodiment, to ensure the best dissolution effect, the duration of introducing hydrogen chloride gas is 10-100 seconds, and the flow rate is controlled within the range of 50-80 slm. By precisely controlling the introduction time and flow rate, the hydrogen chloride gas is ensured to fully contact and react with the reaction products, effectively removing the impurities in the cavity and providing a cleaner environment for subsequent epitaxial growth.

[0056] Specifically, the third stage cleaning specifically includes: S310, introducing hydrogen gas as a cleaning gas into the epitaxial cavity; S320, monitoring the pressure in the epitaxial cavity in real time through a pressure sensor and feeding back to the exhaust pump of the tail gas treatment device, and adjusting the exhaust rate of the exhaust pump to control the pressure of the epitaxial cavity, so that the pressure in the epitaxial cavity and the pressure in the exchange cavity are maintained within the preset value; S330, the impurities in the epitaxial cavity are discharged through the treatment pump of the tail gas treatment device; S340, after the epitaxial growth is completed, the cavity is individually purged for 3 minutes, and the residual small particles in the post-epitaxial cavity are blown out from the exhaust pipeline. In the purging step, the hydrogen flow rate can be adjusted to high or low flow rate; S350, finally, the particle detection equipment is used to monitor the particle concentration in the epitaxial cavity to ensure the cleaning effect; wherein, during the entire third stage cleaning process, the pressure in the epitaxial cavity reaches 1.2 times the pressure of the exchange cavity.

[0057] In the third stage of the cleaning process, hydrogen gas is first introduced into the epitaxial cavity as a cleaning gas S310, then the pressure in the epitaxial cavity is monitored in real time by a pressure sensor, and the data is fed back to the exhaust pump of the exhaust treatment device S320, the exhaust rate is adjusted by the exhaust pump to accurately control the pressure in the epitaxial cavity, and the pressure in the epitaxial cavity is kept within the preset value with the pressure in the exchange cavity, and the pressure in the epitaxial cavity is maintained at 1.2 times the pressure in the exchange cavity during the entire cleaning process to prevent particles from migrating from the exchange cavity to the epitaxial cavity; Next, the impurities in the epitaxial cavity are discharged by the treatment pump of the exhaust treatment device S330, ensuring that there are no residual reactants and impurities in the cavity, and after epitaxial growth, the cavity is purged separately for 3 minutes S340, and the residual small particles in the epitaxial cavity are completely blown out from the exhaust pipeline. In the purging step, the hydrogen flow can be adjusted to a high flow of 60 slm ± 5 or a low flow of 40 slm ± 5 as needed to ensure the cleaning effect in different stages; Finally, the particle detection device is used to monitor the particle concentration in the epitaxial cavity S350 to ensure that the cleaning effect meets the predetermined standard. Through these measures, the small particles in the cavity are effectively removed, and the quality of the epitaxial layer and the performance of the semiconductor device are significantly improved.

[0058] Further, the aeration and exhaust operation is carried out in parallel until the end of the present stage, and in the step of introducing hydrogen gas as a cleaning gas in S310, the aeration rate of the exhaust treatment device is dynamically adjusted to maintain the pressure in the epitaxial cavity by monitoring the pressure change in the epitaxial cavity.

[0059] In the third stage of the cleaning process, the aeration and exhaust operation is carried out in parallel until the end of the present stage, and in particular, in the step of introducing hydrogen gas as a cleaning gas in S310, the pressure change in the epitaxial cavity is monitored in real time by a pressure sensor, and the data is fed back to the exhaust treatment device, and the aeration rate of the exhaust treatment device is dynamically adjusted according to the monitored pressure change to ensure that the pressure in the epitaxial cavity is maintained within the preset value, and in particular, the pressure in the epitaxial cavity is kept at 1.2 times the pressure in the exchange cavity during the entire cleaning process. This precise pressure control ensures the effectiveness and stability of the cleaning process, avoiding the problem of particle generation or migration caused by pressure fluctuations.

[0060] Further, in the third stage of the cleaning process, the purging time of hydrogen gas is 60-120s, and the flow rate of hydrogen gas is 40-60slm; and in the step of purging the epitaxial cavity in S340, the small particles in the cavity are removed by multi-stage purging, first purging with high-flow hydrogen gas 60 slm ± 5 for 30 seconds, then purging with low-flow hydrogen gas 40 slm ± 5 for 30 seconds.

[0061] In the third stage of the cleaning process, the hydrogen purge time is 60-120 seconds, and the hydrogen flow rate is controlled in the range of 40-60 slm. In particular, in the step of purging the epitaxial cavity in S340, a multi-stage purging strategy is adopted: first, purging for 30 seconds with high flow rate hydrogen 60 slm±5, and then purging for another 30 seconds with low flow rate hydrogen 40 slm±5. This multi-stage purging method can more effectively remove small particles remaining in the cavity, ensuring that the cleanliness of the epitaxial cavity reaches the best state.

[0062] It is worth mentioning that in Table 1 below, in this embodiment, the hydrogen flow rate is controlled in the range of 40-60 slm, and the hydrogen purge flow rate is 40 slm. When the flow rate reaches 60 slm, the number of small particles 120 nm particles remaining in the cavity is significantly reduced, and the hydrogen purge flow rate is 60 slm, which is the best when the flow rate reaches 60 slm.

[0063] Table 1

[0064]

[0065] As Table 2 below can more obviously and intuitively show the difference, effectively removing small particles (120 nm particles) in the cavity, significantly improving the quality of the epitaxial layer and the performance of the semiconductor device.

[0066] Table 2

[0067]

[0068] Further, the gas pressure of the exhaust pump is greater than that of the treatment pump, and at the same time that the exhaust treatment device fills the epitaxial cavity with gas, it is pumped through the exhaust pipeline to ensure that the gas flow rate in the epitaxial cavity reaches the preset value; wherein, after opening the exhaust pipeline in S320, the exhaust pipeline is kept open for 10 seconds.

[0069] In the third stage of the cleaning process, the gas pressure of the exhaust pump is set to be greater than that of the treatment pump to ensure effective gas flow and impurity removal. Specifically, in S320, the pressure in the epitaxial cavity is monitored in real time by a pressure sensor, and the data is fed back to the exhaust pump of the exhaust treatment device. In this process, the exhaust treatment device fills the epitaxial cavity with gas while pumping through the exhaust pipeline to ensure that the gas flow rate in the epitaxial cavity reaches the preset value. In order to achieve this goal, after opening the exhaust pipeline, the exhaust pipeline is kept open for 10 seconds to ensure that the gas flow rate is stable and the pressure in the epitaxial cavity is maintained within the preset range. This precise control of gas pressure and gas flow rate prevents particle migration and residue, improving the cleaning effect.

[0070] Further, 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 below a predetermined threshold, thereby ensuring 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 uses a laser scattering method or an optical microscope method S410 to monitor the particle concentration in the epitaxial cavity. The predetermined threshold is set to no more than 8 particles per cubic centimeter S420 to ensure the quality of epitaxial growth. If the detected number of particles exceeds the predetermined threshold, an automatic cleaning program is triggered S430, including but not limited to re-introducing high-flow hydrogen purge for 60 seconds, and re-executing the cleaning steps S300-S340. The particle detection is re-performed S440 after completing the automatic cleaning program until the number of particles meets the predetermined threshold. The data of each detection and cleaning is recorded S450 to generate a report and archive, for subsequent process optimization and quality traceability.

[0071] 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 below a predetermined threshold, thereby ensuring 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 uses a laser scattering method or an optical microscope method S410 to monitor the particle concentration in the epitaxial cavity. The predetermined threshold is set to no more than 8 particles per cubic centimeter S420 to ensure the quality of epitaxial growth. If the detected number of particles exceeds the predetermined threshold, an automatic cleaning program is triggered S430, including but not limited to re-introducing high-flow hydrogen purge for 60 seconds, and re-executing the cleaning steps S300-S340. The particle detection is re-performed S440 after completing the automatic cleaning program until the number of particles meets the predetermined threshold. The data of each detection and cleaning is recorded S450 to generate a report and archive, for subsequent process optimization and quality traceability.

[0072] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, without departing from the technical solution of the present application. Any simplification, modification, equivalent change, and modification of the above embodiments, which do not depart from the technical solution of the present application, are still within the scope of the present application.

Claims

1. An improved method of generating particles between an epitaxial chamber and an exchange chamber, characterized by, The method comprises the following stages: S100, a first stage of removing oxide, increasing the temperature in the epitaxial cavity to a preset temperature, and introducing hydrogen to remove the silicon surface oxide; The first stage of removing oxide specifically comprises: S110, first performing a temperature rising treatment on the epitaxial cavity to ensure that the epitaxial cavity reaches the preset temperature, so as to ensure the stability and uniformity of the epitaxial cavity and avoid the generation of particles due to temperature difference; S120, then introducing hydrogen, the hydrogen reacts with the silicon oxide on the surface of the silicon wafer at the preset temperature to generate water vapor which is volatilized, and the oxide layer is removed, at this time, the pressure in the epitaxial cavity after the introduction of hydrogen is 500-700 Torr; S130, after the removal of the oxide layer, the tail gas treatment device is used to fill hydrogen into the epitaxial cavity, and the gas flow is 60 slm and the purging time is 60 seconds; The preset temperature ranges from 700-900℃, and in the temperature rising process, a step-by-step temperature rising mode is adopted, and each time the temperature is increased by 50℃, the temperature is kept stable for 5 minutes, so as to ensure that the silicon surface oxide is completely removed; by controlling the temperature rising rate, the thermal stress is controlled to be less than 10 MPa, and at the same time, the particle generation amount is controlled to be less than 8 particles per cubic centimeter; wherein, after reaching the preset temperature, the hydrogen flow is controlled to be 40-60 slm, so as 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; S200, a second stage of dissolving impurities, introducing hydrogen chloride gas into the epitaxial cavity to dissolve the metal impurities and part of the impurities in the cavity; the second stage of dissolving impurities specifically comprises: S210, after the hydrogen reaction, the temperature in the epitaxial cavity is kept stable to ensure that the temperature in the epitaxial cavity is stable at 700-900℃; S220, hydrogen chloride gas is introduced into the epitaxial cavity, the hydrogen chloride gas can combine with the water vapor generated after the hydrogen reacts with the silicon oxide in the previous stage to generate hydrochloric acid, and the hydrochloric acid can dissolve the metal particles and part of other impurities on the surface of the silicon wafer; S300, a third stage of cleaning, hydrogen is filled into the epitaxial cavity, and the tail gas treatment device is used to perform a gas extraction treatment on the epitaxial cavity to remove the reactants and impurities in the cavity; the third stage of cleaning specifically comprises: S310, hydrogen is introduced into the epitaxial cavity as a cleaning gas; S320, the pressure in the epitaxial cavity is monitored in real time by a pressure sensor and fed back to the gas extraction pump of the tail gas treatment device, the gas extraction rate is adjusted by the gas extraction pump to control the pressure of the epitaxial cavity, so that the pressure in the epitaxial cavity and the pressure in the exchange cavity are kept within the preset value; S330, the impurities in the epitaxial cavity are discharged by the treatment pump of the tail gas treatment device; S340, after the epitaxial growth is completed, the cavity is purged for 3 minutes alone, the residual small particles in the epitaxial cavity are blown out from the tail gas pipeline, and in the purging step, the hydrogen flow can be adjusted to high flow or low flow; S350, finally, a particle detection device is used to monitor the particle concentration in the epitaxial cavity to ensure the cleaning effect; wherein, during the whole third stage of cleaning, the pressure in the epitaxial cavity reaches 1.2 times the pressure of the exchange cavity; In the third stage of the 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, the small particles in the cavity are removed by multi-stage purging, first purging with high-flow hydrogen 60slm±5 for 30 seconds, and then purging with low-flow hydrogen 40slm±5 for 30 seconds.

2. The method of claim 1 wherein the improvement comprises, The duration of the hydrogen chloride gas purging is 10-100s, and the flow rate of the hydrogen chloride gas is 50-80slm.

3. The method of claim 1 wherein the improvement further comprises, The aeration and air extraction operations are carried out in parallel until the end of this stage, and in the step of purging hydrogen as a cleaning gas in S310, the air charge rate of the exhaust treatment device is dynamically adjusted to maintain the pressure in the epitaxial cavity by monitoring the pressure change in the epitaxial cavity.

4. The method of claim 1 wherein the improvement further comprises, The gas pressure of the exhaust pump is greater than that of the treatment pump, and the exhaust treatment device is filled with gas into the epitaxial cavity while the exhaust gas is extracted through the exhaust gas pipeline to ensure that the gas flow rate in the epitaxial cavity reaches a preset value. After opening the exhaust gas pipeline in S320, the exhaust gas pipeline is kept open for 10 seconds.

5. The method of claim 1 wherein the improvement further comprises After the third stage of cleaning, a fourth stage of verification S400 is also included, which uses 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 below a predetermined threshold to ensure the quality of subsequent epitaxial growth, The fourth stage verification step specifically includes: 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 detected number of particles exceeds the predetermined threshold, an automatic cleaning program is triggered, including but not limited to purging with high-flow hydrogen again for 60 seconds, and re-executing the cleaning steps of S300 to S340; S440, after completing the automatic cleaning program, re-detect the particles until the number of particles meets the predetermined threshold; S450, record the data of each detection and cleaning, generate a report and archive it for subsequent process optimization and quality traceability.

Images