Method of purging a vertical furnace

Abstract

The application provides a vertical furnace purging cleaning method, and relates to the technical field of semiconductor manufacturing, and is designed to solve the problem of poor purging cleaning effect at the edge part in the process of removing the film in the furnace body by using the purging gas provided by the related art. The vertical furnace purging cleaning method comprises the following steps: providing a process cavity of a vertical furnace, and accumulating a film to be removed in the process cavity; performing purging stages in stages, and introducing the purging gas for removing the film into the process cavity in stages, wherein the flow of the purging gas introduced in each purging stage is more than the flow of the purging gas introduced in the previous purging stage; and performing a cleaning stage, and performing pulse type regulation on the pressure in the process cavity. The application makes the purging gas more easily reach and clean the edge part in the process cavity, thereby ensuring the purging cleaning effect on the edge part.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a cleaning method of a vertical furnace. BACKGROUND

[0002] In the semiconductor manufacturing process, the vertical furnace is widely used in diffusion, oxidation, annealing, deposition and other processes as one of the key equipment. In the deposition process, the thin film will not only be deposited on the wafer, but also be deposited on the components in the furnace body, such as the inner wall of the furnace body or the heat preservation barrel, which requires regular dry cleaning of the vertical furnace to ensure the cleanliness of the interior of the furnace body.

[0003] At present, the film layer in the interior of the furnace body is mainly removed by introducing a purge gas into the interior of the furnace body, but the process provided by the related art for removing the film layer in the interior of the furnace body by using the purge gas has the problem of poor cleaning effect at the edge. SUMMARY

[0004] The purpose of the present application is to provide a cleaning method of a vertical furnace to solve the technical problem of poor cleaning effect at the edge in the process provided by the related art for removing the film layer in the interior of the furnace body by using the purge gas.

[0005] The cleaning method of the vertical furnace provided by the present application comprises:

[0006] A process chamber of a vertical furnace is provided, and the process chamber has a thin film to be removed accumulated in the interior thereof;

[0007] A blowing stage is executed in stages, and a purge gas used for removing the thin film is introduced into the process chamber in stages, wherein the flow rate of the purge gas introduced in each blowing stage is greater than the flow rate of the purge gas introduced in the previous blowing stage; and

[0008] A cleaning stage is executed, and the pressure in the interior of the process chamber is adjusted in pulses.

[0009] Further, in the plurality of blowing stages, the flow rate of the purge gas introduced in the previous blowing stage is Q1, and the flow rate of the purge gas introduced in the subsequent blowing stage is Q2, wherein 1.5Q1≤Q2≤3Q1.

[0010] Further, in at least one of the blowing stages, the inlet valve of the purge gas is closed for a first set time period and then opened.

[0011] Further, a temperature gradient along the up-down direction is formed in the interior of the process chamber, and the temperature at the upper part of the process chamber is higher than the temperature at the lower part of the process chamber.

[0012] Further, the upper temperature of the process cavity is Tmax, and the lower temperature of the process cavity is Tmin, wherein Tmax-Tmin≤30℃.

[0013] Further, in at least one of the purge phases, the pressure inside the process cavity is detected and compared with a preset pressure, and when the pressure inside the process cavity drops to the preset pressure, a high-pressure pulse of a second set duration is triggered.

[0014] Further, the purging gas for removing the thin film is introduced into the process cavity, including switching the gas inlet path of the purging gas.

[0015] Further, the switching of the gas inlet path of the purging gas includes periodically alternating the opening of the bottom gas inlet located at the bottom of the vertical furnace and the lateral gas inlet located at the lateral side of the vertical furnace for a third set duration, wherein the lateral gas inlet is opposite to the side wall of both the heat preservation barrel and the crystal boat of the vertical furnace.

[0016] Further, the switching of the gas inlet path of the purging gas includes periodically alternating the opening of one or part of the plurality of bottom gas inlets located at the bottom of the vertical furnace, wherein the gas inlet angles of the plurality of bottom gas inlets are different from each other.

[0017] Further, in the step of pulse regulating the pressure inside the process cavity, the pressure fluctuation range inside the process cavity is-25% to-5% of the reference value, and +5% to +25% of the reference value.

[0018] Further, in the step of pulse regulating the pressure inside the process cavity, at least two pulse regulations are performed; wherein the time interval between adjacent two pulse regulations is between 0.5s and 2s; and / or the duration of a single pulse regulation is 20% to 40% of the required time period of the cleaning phase.

[0019] Further, in the cleaning phase, the rotation speed of the heat preservation barrel of the vertical furnace is increased.

[0020] Further, the purging gas includes fluorine-containing gas and nitrogen, and the volume ratio of the fluorine-containing gas to the nitrogen is between 1:4 and 1:10.

[0021] The vertical furnace purging and cleaning method has the following beneficial effects:

[0022] By dividing the purge gas into multiple stages and passing into the process cavity, in the initial stage, a smaller flow is passed in, and in the subsequent stage, the flow of purge gas passing into the process cavity is gradually increased. By suddenly increasing the flow of purge gas in the latter stage, on the one hand, an impact on the purge gas in the former stage can be formed, so that the purge gas passed in the former stage can flow to the edge part inside the process cavity to complete the cleaning of these areas; on the other hand, the flowability of the purge gas in the latter stage inside the process cavity can also be improved, so that these purge gases can also flow to the edge part inside the process cavity. In the cleaning stage, the pressure inside the process cavity is pulsed, and by pulsing the pressure, the high flowability of the gas in the edge part of the purge stage is formed, the impact force of the gas is improved, and the cleaning effect of the edge part is improved.

[0023] This form of gradually increasing the flow in different stages to pass the purge gas into the process cavity, combined with the pulse regulation of the pressure to clean, makes the purge gas more easily reach the edge part inside the process cavity, and the cleaning effect is significantly improved, thereby ensuring the cleaning effect of the purge of these parts. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0025] Figure 1 The flowchart of the purge cleaning method of the vertical furnace provided by the embodiment of the present application is shown in the figure.

[0026] Figure 2 The structural schematic diagram of the vertical furnace applying the purge cleaning method provided by the embodiment of the present application under one kind of air inlet path is shown in the figure, wherein the hollow arrow represents the air flow path.

[0027] Figure 3 The structural schematic diagram of the vertical furnace applying the purge cleaning method provided by the embodiment of the present application under another kind of air inlet path is shown in the figure, wherein the hollow arrow represents the air flow path.

[0028] Reference signs:

[0029] 100-process cavity; 200-heat preservation barrel; 300-crystal boat; 400-rotation mechanism;

[0030] 110-first air inlet; 120-second air inlet; 130-third air inlet; 140-lateral air inlet; 150-air outlet. DETAILED DESCRIPTION

[0031] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only intended to explain the present application and should not be used to limit the present application.

[0032] As shown in Figure 1 , the embodiment provides a purging cleaning method of a vertical furnace, comprising:

[0033] Step S101, providing a process cavity 100 of a vertical furnace, wherein the inside of the process cavity 100 accumulates a film to be removed.

[0034] Specifically, the structure of the process cavity 100 can be as shown in Figure 2 , a heat preservation barrel 200 is arranged inside the process cavity 100, the heat preservation barrel 200 carries a wafer boat 300, a rotating mechanism 400 for driving the heat preservation barrel 200 to rotate is further arranged inside the process cavity 100, and in addition, the heat preservation barrel 200 is further provided with a heat preservation sheet that rotates synchronously with the heat preservation barrel 200. In the deposition process, the film is not only deposited on the wafer, but also deposited on the inner wall of the process cavity 100 or the heat preservation barrel 200. The material of the film can be silicon nitride.

[0035] Step S102, performing a purging stage in stages, and introducing a purging gas for removing the film into the process cavity 100 in stages, wherein the flow rate of the purging gas introduced in each purging stage is greater than the flow rate of the purging gas introduced in the previous purging stage.

[0036] Specifically, by introducing the purging gas into the process cavity 100 in multiple stages, the purging gas is introduced at a smaller flow rate in the initial stage, and the flow rate of the purging gas introduced into the process cavity 100 is gradually increased in the subsequent stages. By suddenly increasing the flow rate of the purging gas in the subsequent stage, on the one hand, an impact on the purging gas in the previous stage can be formed, so that the purging gas introduced in the previous stage can flow to the edge part inside the process cavity 100 to complete the cleaning of these areas; on the other hand, the flowability of the purging gas in the process cavity 100 can also be improved, so that the purging gas can also flow to the edge part inside the process cavity 100.

[0037] Step S103, performing a cleaning stage, and pulse-regulating the pressure inside the process cavity.

[0038] In the cleaning stage, the purge gas introduced in the purge stage is continuously used, and the stage process at least includes pressure control of the purge gas, forms a local impact, and improves the gas impact force, so that the purge gas can react with the film existing in the process cavity 100, especially effectively clean the edge area, and improve the cleaning effect of the edge part. Specifically, the film existing in the inner wall of the process cavity 100 and the film existing in the heat preservation barrel 200, especially the film in the edge area, reacts to remove the above-mentioned film.

[0039] By pulse regulating the pressure inside the process cavity 100, the pulse pressure change inside the process cavity 100 can be generated, and the local impact of the purge gas can be formed to improve the flowability of the purge gas inside the process cavity 100, especially the flowability and impact force of the gas in the edge part, thereby improving the cleaning effect of the edge part.

[0040] It should be noted that the gas outlet 150 of the vertical furnace is connected with an exhaust pump, and the exhaust pump can be used to exhaust the gas inside the process cavity 100. The pulse pressure regulation inside the process cavity 100 can also be controlled by controlling the exhaust speed of the exhaust pump. Specifically, the process cavity 100 has a pressure control mode, and in the pressure control mode, the reference pressure inside the process cavity 100 can be controlled to be, for example, 100mtorr. When the pulse pressure regulation inside the process cavity 100 is performed, the pressure can be increased or decreased based on the above-mentioned reference pressure.

[0041] In the embodiment, the duration of each purge stage can be the same or different. When the duration of each purge stage is different, the time of the latter stage can be increased compared to the time of the former stage. The gas flow with stronger impact force is combined with longer purge time, which can further enhance the flowability of the gas flow.

[0042] In the embodiment, the time of each purge stage can be controlled to be more than 10 minutes. In order to improve the purge effect, it can also be increased to 1 hour, and can be further increased to 6-12 hours.

[0043] In the embodiment, in the plurality of purge stages, the flow rate of the purge gas introduced in the former purge stage is Q1, and the flow rate of the purge gas introduced in the latter purge stage is Q2, wherein 1.5Q1≤Q2≤3Q1. For example, when there are two purge stages, the flow rate of the purge gas introduced in the second stage is 1.5-3 times the flow rate of the purge gas introduced in the first stage; when there are three purge stages, the flow rate of the purge gas introduced in the second stage is 1.5-3 times the flow rate of the purge gas introduced in the first stage, and the flow rate of the purge gas introduced in the third stage is 1.5-3 times the flow rate of the purge gas introduced in the second stage.

[0044] Through the above setting, on the one hand, the impact effect of the previous stage purge gas can be avoided due to the too small flow difference between the next stage and the previous stage, and on the other hand, waste can also be avoided due to the too large flow of the purge gas.

[0045] In the embodiment, in at least one purge stage, the intake valve of the purge gas can be closed for a first set time length, and then opened.

[0046] When the purge gas is introduced into the process chamber 100, the intake valve of the purge gas can be closed first, at this time, under the action of the subsequent flow of the purge gas, the front purge gas will accumulate in the corresponding intake pipeline; after a first set time length, when the intake valve is opened, the purge gas accumulated in the intake pipeline will instantly flow into the process chamber 100.

[0047] Through the above setting, the impact force of the purge gas on the intake pipeline and the process chamber 100 can be increased to form a turbulent effect inside the process chamber 100, thereby improving the diffusion uniformity of the purge gas inside the process chamber 100, so that the purge gas can flow smoothly to the edge of the process chamber 100. The consistency of the cleaning effect inside the process chamber 100 is ensured.

[0048] In the embodiment, a temperature gradient along the up-down direction is formed inside the process chamber 100, wherein the temperature of the upper part of the process chamber 100 is higher than the temperature of the lower part of the process chamber 100.

[0049] By forming the above temperature gradient inside the process chamber 100, compared with the case that the temperature is consistent inside the process chamber 100, the flowability of the purge gas can be increased, which is beneficial to the flow of the purge gas to the edge area inside the process chamber 100.

[0050] In addition, in the deposition process, due to the control of the process temperature, the film formed on the upper part of the process chamber 100 is thicker, so by forming the above temperature gradient inside the process chamber 100, the cleaning rate difference between the upper part and the lower part of the process chamber 100 can also be increased, so that the cleaning rate of the upper part of the process chamber 100 is higher, thereby ensuring that the upper part and the lower part of the process chamber 100 are basically consistent after cleaning.

[0051] In the embodiment, the temperature of the upper part of the process chamber 100 is Tmax, and the temperature of the lower part of the process chamber 100 is Tmin, wherein Tmax-Tmin≤30℃.

[0052] By controlling the temperature difference between the upper part and the lower part of the process chamber 100 within the above range, it can be prevented that the purge gas is concentrated in the upper part due to the too large temperature difference between the upper and lower parts, thereby affecting the cleaning efficiency of the lower part of the process chamber 100.

[0053] It should be noted that the vertical furnace is provided with an upper heater and a lower heater, wherein the upper heater and the lower heater can be adjusted to a required temperature respectively, so as to form a temperature gradient in the vertical direction inside the process cavity 100.

[0054] In this embodiment, in at least one purging stage, the pressure inside the process cavity 100 is detected and compared with a preset pressure, and when the pressure inside the process cavity 100 drops to the preset pressure, a high-pressure pulse of a second set duration is triggered.

[0055] This setting can ensure that the process cavity 100 has sufficient pressure when the pressure inside the process cavity 100 drops by triggering a high-pressure pulse, avoid the influence of low pressure on the purging efficiency, and increase the removal effect on the thin film.

[0056] It should be noted that in practice, the machine has a pressure value detection function, by which real-time detection of the pressure inside the process cavity 100 can be realized. Moreover, the process cavity 100 has a pressure control mode to control the pressure value of the process cavity 100. Specifically, when the gas flow is constant, the opening angle of the air pump can be controlled to achieve the purpose of pressure control. When the gas flow is constant, to trigger a high-pressure pulse, the opening angle of the air pump can be reduced to increase the flow rate and pressure of the gas flow; the air pump power can also be increased to increase the gas flow, so that the opening angle of the air pump remains fixed. Preferably, the triggering of the high-pressure pulse can be realized by reducing the opening angle of the air pump.

[0057] Specifically, the second set duration can be 2s-4s, preferably 3s; the pressure value of the high-pressure pulse can fluctuate upward by 10%-20% based on the reference pressure, preferably 15%.

[0058] In this embodiment, the purging gas for removing the thin film is introduced into the process cavity 100, comprising: switching the gas inlet path of the purging gas.

[0059] By making the purging gas enter the process cavity 100 through different gas inlet paths, the process cavity 100 can be purged in all directions, so that the purging gas can more easily reach the edge parts inside the process cavity 100 to ensure the cleaning effect of these parts.

[0060] Specifically, the above-mentioned switching of the gas inlet path of the purging gas comprises: alternately opening the bottom gas inlet at the bottom of the vertical furnace and the lateral gas inlet 140 at the lateral side of the vertical furnace periodically for a third set duration, wherein the lateral gas inlet 140 is opposite to the side walls of both the heat preservation barrel 200 and the crystal boat 300 of the vertical furnace.

[0061] During the purging process, as shown in FIG. 6, the bottom gas inlet and the lateral gas inlet 140 are alternately opened periodically for a third set duration, so that the purging gas can enter the process cavity 100 through the bottom gas inlet and the lateral gas inlet 140 alternately. Figure 2As shown, the bottom gas inlet can be opened first, and the lateral gas inlet 140 can be closed, so that the purge gas enters only through the bottom gas inlet; then, as shown, Figure 3 the bottom gas inlet can be closed again, and the lateral gas inlet 140 can be opened, so that the purge gas enters only through the lateral gas inlet. Of course, the lateral gas inlet 140 can be opened first, and the bottom gas inlet can be closed, and then the lateral gas inlet 140 can be closed, and the bottom gas inlet can be opened. The present embodiment does not limit the opening sequence of the lateral gas inlet 140 and the bottom gas inlet.

[0062] This arrangement allows the purge gas to enter the process chamber alternately from the bottom and the side of the vertical furnace. When the gas flow enters from the bottom gas inlet, it will not be blocked by the gas flow entering from the lateral gas inlet 140, and similarly, when the gas flow enters from the lateral gas inlet 140, it will not be blocked by the gas flow entering from the bottom gas inlet, so that the purge gas is more easily to reach the edge corners.

[0063] In the present embodiment, the third set duration is between 30s and 120s.

[0064] By switching the gas inlet path every 30s to 120s, on the one hand, it can avoid the area corresponding to the gas inlet path from being insufficiently purged due to high switching frequency, and on the other hand, it can also avoid low film removal efficiency due to low switching frequency.

[0065] Preferably, the gas inlet path can be switched every 60s.

[0066] In other embodiments, switching the gas inlet path of the purge gas can also include alternately opening one or part of the plurality of bottom gas inlets located at the bottom of the vertical furnace, wherein the gas inlet angles of the plurality of bottom gas inlets are different from each other.

[0067] Through the above arrangement, the purge gas can have different gas inlet angles when entering the inside of the process chamber 100 through different bottom gas inlets, thereby facilitating the flow of the purge gas to the edge area inside the process chamber 100, and further achieving omnidirectional purging inside the process chamber 100.

[0068] Please continue to refer to Figure 2In the embodiment, three bottom air inlets are taken as an example for illustration, wherein the three bottom air inlets can be the first air inlet 110, the second air inlet 120 and the third air inlet 130. The above air inlet path can be, for example, only one of the first air inlet 110, the second air inlet 120 and the third air inlet 130 is opened, and the lateral air inlet 140 is closed, or any two of the first air inlet 110, the second air inlet 120 and the third air inlet 130 are opened, and the lateral air inlet 140 is closed, or the first air inlet 110, the second air inlet 120 and the third air inlet 130 are all opened, and the lateral air inlet 140 is closed, and so on.

[0069] In the embodiment, the switching interval of the air inlet of the different bottom air inlets can also be between 30s and 120s.

[0070] In the embodiment, the pressure inside the process chamber 100 can be pulse-regulated during the cleaning stage.

[0071] In the embodiment, the pressure inside the process chamber 100 can be pulse-regulated during the cleaning stage.

[0072] By setting the fluctuation range of the pulse pressure regulation to be between 5% and 25% of the reference value, on the one hand, the influence of the flowability of the gas flow caused by the too small pressure fluctuation can be avoided, and on the other hand, the damage to the internal structure of the process chamber 100 caused by the too large pressure fluctuation can also be avoided.

[0073] Specifically, when the reference pressure inside the process chamber 100 is 100mtorr, and the pulse pressure regulation of the process chamber 100 is needed, the pressure fluctuation range inside the process chamber 100 can be controlled, such as setting the pulse peak value to 75mtorr, 95mtorr, 105mtorr or 125mtorr, etc. Through the pulse pressure regulation, a large pressure change is realized, the impact force of the purge gas is improved, especially the impact force of the edge area, and thus the cleaning effect of the edge part is improved.

[0074] In the embodiment, the pressure inside the process chamber 100 can be pulse-regulated during the cleaning stage.

[0075] By controlling the time interval of the two pressure adjustments to be between 0.5s and 2s, on the one hand, the cost increase caused by too high pressure adjustment frequency can be avoided, and on the other hand, the decline in the effect of the gas flow caused by too low pressure adjustment frequency can also be avoided.

[0076] In this embodiment, the duration of the single pulse adjustment is 20% to 40% of the required time period of the cleaning phase. This setting can ensure that the purge gas inside the process chamber 100 obtains sufficient pulse pressure adjustment, so that the flowability of the purge gas is enhanced, so that it can smoothly diffuse to the edge area inside the process chamber 100, thereby ensuring the cleaning effect on the edge area.

[0077] In this embodiment, the rotation speed of the holding barrel 200 of the vertical furnace can also be increased during the cleaning phase.

[0078] When the holding barrel 200 rotates, the holding sheet also rotates synchronously. By increasing its rotation speed, the relative flow rate of the purge gas, especially the flow rate of the edge area, can be increased. In addition, due to the increase in the rotation speed of the holding barrel, the purge gas forms a vortex at the edge position, and the local airflow is stirred by the vortex to improve the cleaning effect at the edge position, thereby enhancing the cleaning effect on the holding barrel 200, the holding sheet and other areas that are difficult to clean.

[0079] Specifically, the rotation speed of the holding barrel 200 is increased from the ordinary 2r / min to 10-15r / min.

[0080] In this embodiment, the purge gas can include fluorine-containing gas and nitrogen, and the volume ratio of the fluorine-containing gas to the nitrogen is between 1:4 and 1:10.

[0081] The fluorine-containing gas can react with the thin film inside the process chamber 100. Specifically, when the fluorine-containing gas is fluorine gas, the chemical reaction formula with the thin film is as follows:

[0082] F2+Si3N4→SiF4↑+N2↑ (1)

[0083] After the removal of the thin film is completed, the nitrogen can be used to carry out the reaction by-products out of the process chamber 100, and the purge gas is also removed to avoid the formation of residues of the reaction by-products and the purge gas inside the process chamber 100.

[0084] Preferably, when the fluorine-containing gas is fluorine gas, the volume fraction ratio of the fluorine gas to the nitrogen is 1:4.

[0085] In other embodiments, the fluorine-containing gas can also be NF3 or ClF3 and other fluorine-based gases.

[0086] In addition, the purge gas can also include one or more gases such as NO, N2O, HF, H2, etc. in addition to the mixture of fluorine gas and nitrogen gas in a volume ratio of 1:4.

[0087] In this embodiment, the temperature inside the process chamber 100 is between 300℃ and 450℃.

[0088] The purge cleaning method of the vertical furnace is described below through two specific embodiments.

[0089] Embodiment One

[0090] The process chamber 100 is heated to 380℃, and a mixture of fluorine gas and nitrogen gas in a volume ratio of 1:4 is introduced as the purge gas, with an initial flow rate of 20 SLM for 5 minutes.

[0091] The flow rate of the purge gas is increased to 35 SLM for 8 minutes.

[0092] The flow rate of the purge gas is increased to 50 SLM for 10 minutes.

[0093] The temperature of the upper heater of the process chamber 100 is adjusted to 395℃, and the temperature of the lower heater of the process chamber 100 is adjusted to 375℃ to form a temperature gradient in the up-down direction.

[0094] During the cleaning stage, the pressure fluctuation range inside the process chamber 100 is controlled to be ±10% of the reference pressure for 6 minutes.

[0095] The purge cleaning method provided by this embodiment one can reduce the residue at the edge of the insulation sheet by 62% and shorten the cleaning time by 18%.

[0096] Embodiment Two

[0097] During the purge stage, the gas inlet path is switched every 60 seconds, for example: Figure 2 First, the bottom gas inlet is controlled to be open and the side gas inlet 140 is controlled to be closed, as shown in FIG. 6A. Figure 3 After 60 seconds, the bottom gas inlet is controlled to be closed and the side gas inlet 140 is controlled to be open, as shown in FIG. 6B.

[0098] When the purge gas enters the process chamber 100 through the side gas inlet 140, the side gas inlet 140 is first controlled to be closed for a certain period of time and then controlled to be open, so that the purge gas entering through the side gas inlet 140 can impact the side wall of the insulation barrel 200.

[0099] During the purge process, the pressure value inside the process chamber 100 is detected in real time, and when a pressure drop greater than 5% is detected, a 3s high-pressure pulse is triggered, wherein the high-pressure pulse is 1.15 times the reference pressure.

[0100] After the cleaning stage, an exhaust stage is further included, specifically, first, the gas is extracted through the gas outlet 150 for 5 minutes, then the gas outlet 150 is closed; nitrogen is filled into the process cavity 100 through the gas inlet until a certain pressure, for example, 10 torr, and then the gas is extracted, and the above process is repeated for 3-5 times, so that the fluorine gas is completely extracted outside the process cavity 100. In the filling process of nitrogen, the fluorine-containing gas at the edge of the process cavity 100 can be brought out.

[0101] Through the purging cleaning method provided by this embodiment two, the film residue at the edge of the process cavity 100 can be reduced by 20%-40%, and the consumption of purging gas can be reduced by 12%-20%.

[0102] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be defined by the scope defined in the claims.

[0103] Finally, it should be noted that in this document, the terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or device. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0104] In the above embodiments, the description of the orientation such as "upper", "lower", "lateral" and the like is based on the drawings.

[0105] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of purging cleaning of a vertical furnace, characterized by, The process chamber of a vertical furnace is provided with a thin film to be removed accumulated inside the process chamber; A temperature gradient is formed in the process chamber along the vertical direction, with the temperature of the upper part of the process chamber being higher than that of the lower part of the process chamber; The purge phase is executed in stages, and the purge gas for removing the thin film is introduced into the process chamber in stages, wherein the flow rate of the purge gas introduced in each purge phase is greater than that of the purge gas introduced in the previous purge phase; And The pressure inside the process chamber is pulsed adjusted in the cleaning phase. In the plurality of purge phases, the flow rate of the purge gas introduced in the previous purge phase is Q1, and the flow rate of the purge gas introduced in the subsequent purge phase is Q2, wherein 1.5Q1≤Q2≤3Q1.

2. The purging cleaning method of a vertical furnace according to claim 1, characterized by, In at least one of the purge phases, the inlet valve of the purge gas is closed for a first set period of time and then opened.

3. The purging cleaning method of a vertical furnace according to claim 1, characterized by, The temperature of the upper part of the process chamber is Tmax, and the temperature of the lower part of the process chamber is Tmin, wherein Tmax-Tmin≤30℃.

4. The purging cleaning method of a vertical furnace according to claim 1, characterized by, In at least one of the purge phases, the pressure inside the process chamber is detected and compared with a preset pressure, and when the pressure inside the process chamber drops to the preset pressure, a high pressure pulse of a second set period of time is triggered.

5. The purging cleaning method of a vertical furnace according to claim 1, characterized by, The purge gas for removing the thin film is introduced into the process chamber, including switching the inlet path of the purge gas.

6. The purging cleaning method of a vertical furnace according to claim 1, characterized by, The switching of the inlet path of the purge gas includes periodically alternating the opening of the bottom inlet located at the bottom of the vertical furnace and the lateral inlet located at the lateral side of the vertical furnace for a third set period of time, wherein the lateral inlet is opposite to the side wall of both the heat preservation barrel and the crystal boat of the vertical furnace.

7. The purging cleaning method of a vertical furnace according to claim 6, characterized by, The switching of the inlet path of the purge gas includes alternately opening one or part of the plurality of bottom inlets located at the bottom of the vertical furnace, wherein the inlet angles of the plurality of bottom inlets are different from each other.

8. The purging cleaning method of a vertical furnace according to claim 6, characterized by, In the step of pulsed adjusting the pressure inside the process chamber, the pressure fluctuation range inside the process chamber is-25% to-5% of the reference value, and +5% to +25% of the reference value.

9. Purge cleaning method of a vertical furnace according to any one of claims 1-8, characterized in that, In the step of pulsed adjusting the pressure inside the process chamber, at least two pulsed adjustments are performed; wherein the time interval between adjacent two pulsed adjustments is between 0.5s and 2s, and / or the duration of a single pulsed adjustment is 20% to 40% of the required time period of the cleaning phase.

10. A purging cleaning method of a vertical furnace according to any one of claims 1 to 8, characterized in that, In the cleaning phase, the rotation speed of the heat preservation barrel of the vertical furnace is increased.

11. Purge cleaning method of a vertical furnace according to any one of claims 1-8, characterized in that, The purge gas includes fluorine-containing gas and nitrogen, and the volume ratio of the fluorine-containing gas to the nitrogen is between 1:4 and 1:

10.

12. Purge cleaning method of a vertical furnace according to any one of claims 1-8, characterized in that, ​

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