Semiconductor apparatus and process cavity maintenance method

Abstract

The application discloses a semiconductor device and a process cavity maintenance method. The maintenance method comprises the following steps: providing a process cavity, a target film layer is deposited on the inner wall of the process cavity, and the target film layer is a semi-insulating oxygen-doped polysilicon film layer; a first gas is introduced into the process cavity, the target film layer is subjected to a first treatment, the target film layer is oxidized to form an oxidized target film layer, and the oxidized target film layer is cracked and peeled off under the action of stress, and the first gas is an oxidizing gas; and a second gas is introduced into the process cavity, and the process cavity is purged. The application can realize online maintenance of the process cavity, maintain the particle performance at a good level, has the advantages of simpler, more reliable, more efficient and faster maintenance, and can greatly reduce the labor cost and the material cost.

Description

Technical Field

[0001] This application relates to the field of semiconductor equipment technology, and in particular to a method for maintaining semiconductor equipment and process cavities. Background Technology

[0002] Semi-insulating oxygen-doped polycrystalline silicon (SIPOS), used as a passivation film for high-voltage devices, not only possesses the advantages of insulating passivation films but also overcomes the shortcomings of ordinary insulating passivation layers, such as the inability to prevent charge accumulation or ion contamination on the device surface. The conventional SIPOS process involves growing and doping the SIPOS film on the wafer surface via LPCVD chemical reactions in a furnace tube. Its main process steps involve SiH4 decomposition and N2O doping. N2O is readily decomposed, allowing oxygen doping into the Si (polycrystalline silicon) structure, forming a SIPOS film structure with a certain oxygen content on the wafer surface.

[0003] As the process reaction continues, SIPOS films are deposited simultaneously on the inner wall of the process chamber and the surface of the wafer boat. However, when the SIPOS film reaches a certain thickness on the inner wall of the process chamber, it cracks and peels off due to stress release, resulting in particle generation. These particles concentrate on the wafer surface near the bottom of the process chamber, mainly exhibiting a circumferential ring distribution with numerous peeling particles larger than 1 micrometer in diameter. This problem severely affects the semi-insulating properties of the SIPOS film deposited on the wafer.

[0004] Traditional solutions for improving particle removal within process chambers include two approaches. One is to cover the inner wall of the process chamber with dense polycrystalline silicon, encapsulating the SIPOS film deposited on the inner wall to reduce the likelihood of SIPOS film peeling off. However, after the SIPOS film reaches a certain thickness, stress gradually accumulates and cannot be reversed, forming a loose film structure. This loose film structure is the source of a large number of peeling particles, so covering it is not an effective way to reduce the amount of peeling particles. Another approach is to disassemble the process chamber, clean and replace components to improve particle removal. However, this method requires specialized skills and results in significant downtime. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned problems existing in the prior art and to provide a method for maintaining semiconductor equipment and process cavities.

[0006] To achieve the above objectives, the technical solution of this application is as follows:

[0007] According to a first aspect of this application, embodiments of this application provide a method for maintaining a process cavity, including:

[0008] A process cavity is provided, and a target film layer is deposited on the inner wall of the process cavity. The target film layer is a semi-insulating oxygen-doped polycrystalline silicon film layer.

[0009] A first gas is introduced into the process chamber to perform a first treatment on the target film layer, causing the target film layer to be oxidized to form an oxidized target film layer, which then cracks and peels off under stress. The first gas is an oxidizing gas.

[0010] A second gas is introduced into the process chamber to purge it.

[0011] In some embodiments, the target film layer is subjected to the first treatment for a first time by introducing the first gas at a first temperature and a first flow rate at a first temperature. The difference between the thermal expansion coefficient of the oxidized target film layer and the thermal expansion coefficient of the inner wall of the process chamber causes the oxidized target film layer to crack due to stress difference, forming a loose film structure. The accumulated stress is released during the first treatment, causing the oxidized target film layer with the loose film structure to peel off.

[0012] In some embodiments, the first temperature is 500°C to 650°C.

[0013] In some embodiments, the first flow rate is 1000 sccm to 5000 sccm.

[0014] In some embodiments, the first time T and the thickness H of the target film have the following relationship: H:T = 5:1 to 7:1, where H is in micrometers and T is in hours.

[0015] In some embodiments, the step of introducing a second gas into the process chamber to purge the process chamber specifically includes:

[0016] Before the first gas is introduced, a third gas with a second flow rate is introduced into the process chamber at a second temperature to purge the process chamber for the first time, and the introduction of the third gas is stopped during the first process.

[0017] After the first treatment is completed, the introduction of the first gas is stopped, and at the third temperature, a fourth gas with a third flow rate is introduced into the process chamber to perform a second purging of the process chamber.

[0018] The second gas includes the third gas and the fourth gas.

[0019] In some embodiments, the oxidizing gas includes oxygen.

[0020] In some embodiments, the third gas and the fourth gas comprise nitrogen or an inert gas.

[0021] The second temperature is 15℃~25℃.

[0022] In some embodiments, the third temperature is 15°C to 25°C.

[0023] In some embodiments, the second flow rate is 500 sccm to 1000 sccm.

[0024] In some embodiments, the third flow rate is 5000 sccm to 10000 sccm.

[0025] In some embodiments, during the second purging, the oxidized target film remaining on the inner wall of the process chamber is further subjected to a second treatment to promote its peeling off, the second treatment including at least one of the following (1) to (3):

[0026] (1) The third flow rate is changed from large to small and then from small to large between 5000 sccm and 10000 sccm; or, the third flow rate is changed periodically between 5000 sccm and 10000 sccm by repeatedly increasing and decreasing, so as to generate impact oscillation.

[0027] (2) The pressure inside the process chamber is periodically changed between 1 Torr and 300 Torr by repeatedly increasing and decreasing to generate pressure oscillation;

[0028] (3) The third temperature is periodically changed between 20°C and 200°C by repeatedly increasing and decreasing to generate temperature oscillation.

[0029] In some embodiments, the process chamber is a vertical furnace reaction chamber capable of accommodating a crystal boat, on which the target film layer is also deposited. When maintaining the process chamber, the process includes performing the first treatment on the target film layer on the crystal boat in an unloaded state to form the oxidized target film layer, and performing the second treatment on the residual oxidized target film layer on the crystal boat. The inner wall material of the process chamber and the material of the crystal boat include silicon carbide.

[0030] According to a second aspect of this application, embodiments of this application also provide a semiconductor device, the semiconductor device including a process cavity and a maintenance system, the maintenance system performing maintenance using a process cavity maintenance method as provided in any embodiment of the first aspect above, the maintenance system including:

[0031] The first gas supply unit includes a first gas supply port, which is disposed on the process cavity. The first gas supply unit is used to introduce a first gas into the process cavity through the first gas supply port for first processing.

[0032] The second air supply unit includes a second air supply port, which is disposed on the process cavity. The second air supply unit is used to introduce a second gas into the process cavity through the second air supply port for purging.

[0033] The control module is used to control the on / off state of the first air supply port and the second air supply port to perform the first processing and the purging.

[0034] In some embodiments, the semiconductor device is a vertical furnace device, and the semiconductor device further includes:

[0035] Temperature control unit, used to control the temperature inside the process chamber;

[0036] The flow control unit is used to control the on / off state of the first gas supply port and the second gas supply port, so as to control the inflow rate of the first gas and the second gas.

[0037] The pressure control unit is used to control the pressure inside the process chamber;

[0038] The control module is also used to control the temperature control unit, the flow control unit, and the pressure control unit to perform:

[0039] At a first temperature, the first gas at a first flow rate is introduced, and the first treatment is performed for a first time.

[0040] Furthermore, before introducing the first gas, a third gas at a second flow rate is introduced at a second temperature for a first purging, and the introduction of the third gas is stopped during the first treatment; after the first treatment is completed, the introduction of the first gas is stopped, and a fourth gas at a third flow rate is introduced at a third temperature for a second purging; the second gas includes the third gas and the fourth gas.

[0041] Furthermore, a second treatment is also performed during the second purging.

[0042] In some embodiments, the first gas supply unit further includes a first gas supply pipeline, with a first end connected to a first gas source and a second end connected to the first gas supply port.

[0043] In some embodiments, the second gas supply unit further includes a second gas supply pipeline, the first end of which is connected to a second gas source, and the second end of which is connected to the second gas supply port.

[0044] In some embodiments, the first air supply port and the second air supply port coincide, and the second end of the first air supply pipeline coincides with the second end of the second air supply pipeline.

[0045] In some embodiments, the temperature control unit includes a heating device and a cooling device disposed on the process chamber.

[0046] In some embodiments, the flow control unit includes flow control devices disposed at a first end of the first gas supply line and a first end of the second gas supply line.

[0047] In some embodiments, the pressure control unit includes a vacuum unit and an automatic pressure control unit. The vacuum unit is connected to a first end of an exhaust pipe, and the second end of the exhaust pipe is connected to the process chamber. The automatic pressure control unit is located on the exhaust pipe and is used to control the vacuum unit to evacuate the process chamber through the exhaust pipe.

[0048] In some embodiments, the control module is signal-connected to the heating device, the cooling device, the flow control device, and the automatic pressure control unit to control the first temperature to the third temperature, the first flow rate to the third flow rate, and the pressure.

[0049] The embodiments of this application may have, or at least have, the following advantages:

[0050] (1) By introducing an oxidizing gas (first gas) into the process chamber, the semi-insulating oxygen-doped polycrystalline silicon (SIPOS) film deposited on the inner wall of the process chamber is oxidized (first treatment). The significant difference in the thermal expansion between the oxidized semi-insulating oxygen-doped polycrystalline silicon film and the inner wall of the process chamber at the high temperature (first temperature) during oxidation can be utilized to cause cracks in the oxidized semi-insulating oxygen-doped polycrystalline silicon film due to stress differences, forming a loose film structure. As the accumulated stress is released in the first treatment, the oxidized semi-insulating oxygen-doped polycrystalline silicon film with a loose film structure can be peeled off from the inner wall of the process chamber, realizing online maintenance of the process chamber. This effectively solves the shortcomings of traditional maintenance methods and ensures that the particle performance in the SIPOS process reaction is maintained at a good level.

[0051] (2) By using impact oscillation, pressure oscillation and / or temperature oscillation during the second purging, the residual oxidized semi-insulating oxygen-doped polycrystalline silicon film on the inner wall of the process cavity is subjected to a second treatment, which can promote the complete peeling of the residual oxidized semi-insulating oxygen-doped polycrystalline silicon film from the inner wall of the process cavity, thereby achieving a high-level cleaning and maintenance of the process cavity. It has the advantages of being efficient and fast, and can greatly reduce labor and material costs.

[0052] (3) By setting up a maintenance system on the semiconductor equipment, the maintenance system includes a first gas supply unit, a second gas supply unit, a temperature control unit, a flow control unit and a pressure control unit, and is controlled by a control module. This is beneficial to realize the maintenance system by utilizing the semiconductor equipment's own configuration, making online maintenance of the process chamber simpler and more reliable, and fully ensuring the continuous and stable operation of the SIPOS process.

[0053] Other advantages of this application will be described in the following detailed description. Attached Figure Description

[0054] Figure 1 This is a flowchart of a process cavity maintenance method according to a preferred embodiment of this application.

[0055] Figure 2 This is a structural schematic diagram of an exhaust pipe maintenance system provided in a preferred embodiment of this application.

[0056] In the diagram: 1. Second gas supply line; 2. Auxiliary gas source; 3. Process gas source; 4. First gas supply line; 5. Mass flow controller; 6. Process chamber; 7. First gas inlet; 8. Second gas inlet; 9. Crystal boat; 10. Exhaust port; 11. Automatic pressure controller; 12. Exhaust line; 13. Vacuum pump; 14. Process chamber door; 100. Vertical furnace equipment. Detailed Implementation

[0057] To address the shortcomings of existing technologies, such as using dense polycrystalline silicon to cover the inner wall surface of the process cavity and encapsulating the SIPOS film layer deposited on the inner wall of the process cavity, which still cannot effectively reduce the amount of detached particles, and the need for disassembling the process cavity for component cleaning and replacement, which requires specialized skills and results in significant downtime, this application provides a process cavity maintenance method, including:

[0058] A process cavity is provided, and a target film layer is deposited on the inner wall of the process cavity. The target film layer is a semi-insulating oxygen-doped polycrystalline silicon film layer.

[0059] A first gas is introduced into the process chamber to perform a first treatment on the target film layer, causing the target film layer to be oxidized to form an oxidized target film layer, which then cracks and peels off under stress. The first gas is an oxidizing gas.

[0060] A second gas is introduced into the process chamber to purge it.

[0061] This application embodiment introduces an oxidizing gas into the process chamber to perform a first oxidation-based treatment on the semi-insulating oxygen-doped polycrystalline silicon (SIPOS) film deposited on the inner wall of the process chamber. Utilizing the significant difference in thermal expansion between the oxidized semi-insulating oxygen-doped polycrystalline silicon film and the inner wall of the process chamber at the high temperature (first temperature) during oxidation, the oxidized semi-insulating oxygen-doped polycrystalline silicon film develops cracks due to stress differences, forming a loose film structure. As the accumulated stress is released during the first treatment, the oxidized semi-insulating oxygen-doped polycrystalline silicon film with its loose film structure can peel off from the inner wall of the process chamber, achieving online maintenance of the process chamber. This effectively solves the aforementioned shortcomings of traditional maintenance methods and ensures that the particle performance in the SIPOS process reaction remains at a good level.

[0062] This application also provides a semiconductor device, which includes a process chamber and a maintenance system, wherein the maintenance system is maintained using the process chamber maintenance method described above.

[0063] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0064] refer to Figure 1 A method for maintaining a process cavity according to an embodiment of this application includes the following steps:

[0065] Step S11: Provide the process cavity that needs maintenance.

[0066] The process chamber can be a chamber used for depositing SIPOS films, such as a chemical vapor deposition chamber. As the SIPOS process reaction continues, SIPOS films are deposited simultaneously on the inner wall of the process chamber and the surface of the wafer. When the SIPOS film reaches a certain deposition thickness on the inner wall of the process chamber, it will crack and peel off due to stress release, resulting in particle generation. This problem will seriously affect the semi-insulating properties of the SIPOS film deposited on the wafer, therefore, it is necessary to maintain the process chamber and perform a peeling treatment on the SIPOS film (target film) deposited on the inner wall of the process chamber.

[0067] refer to Figure 2 In some embodiments, the process chamber 6 may be disposed on the vertical furnace equipment 100 (vertical furnace tube equipment). That is, the process chamber 6 is the process chamber 6 of the vertical furnace equipment 100, and is used to deposit a SIPOS film layer on the surface of the wafer loaded on the crystal boat 9. Figure 2 (This is displayed as an empty state when no wafers are loaded on the crystal boat 9). However, it is not limited to this. The following will take the maintenance of the process chamber 6 of the vertical furnace equipment 100 as an example to describe in detail the specific implementation of a process chamber maintenance method of this application.

[0068] During the SIPOS process, a SIPOS film layer (target film layer) of a certain thickness will be deposited on the inner wall of the process chamber 6 of the vertical furnace equipment 100. In order to prevent the SIPOS film layer from peeling off during the subsequent SIPOS process and causing particles to be generated, the process chamber maintenance method of this application embodiment can be used under preset conditions (e.g., when a threshold is triggered) to actively peel off the SIPOS film layer, so that the inner wall of the process chamber 6 becomes clean after maintenance.

[0069] Step S12: Introduce the first purging gas into the process chamber to purge the process chamber for the first time.

[0070] In some embodiments, after the process chamber door 14 is closed, a third gas, serving as the first purging gas, can be introduced into the process chamber 6 through the second gas supply port 8 to perform a first purging of the process chamber 6. The process chamber 6 is provided with an exhaust port 10, which is connected to an exhaust pipe 12. A vacuum pump 13 (vacuum unit) is provided at the end (first end) of the exhaust pipe 12. The introduced third gas can be discharged through the exhaust port 10 into the exhaust pipe 12 by the suction action of the vacuum pump 13. This process can also purge valves on various pipelines, perform leak checks by gas filling, and confirm the status of temperature and pressure control, ensuring that the process chamber 6 is in a stable state suitable for maintenance. The third gas originates from the auxiliary gas source 2 (second gas source) and is supplied to the second gas supply port 8 through the second gas supply pipe 1. The second gas includes the third gas.

[0071] In some embodiments, at a second temperature, a third gas with a second flow rate is introduced into the process chamber 6 to perform a first purging of the process chamber 6.

[0072] In some embodiments, the third gas includes nitrogen. Alternatively, the third gas includes an inert gas, such as argon.

[0073] In some embodiments, the second temperature is 15°C to 25°C (room temperature).

[0074] In some embodiments, the second flow rate is 500 sccm to 1000 sccm. For example, the second flow rate can be 500 sccm, 600 sccm, 700 sccm, 800 sccm, 900 sccm, or 1000 sccm, or any value between any two of the aforementioned flow rate values. However, it is not limited to this.

[0075] In some embodiments, the temperature inside the process chamber 6 may be maintained at a second temperature by utilizing ambient temperature or by means of a cooling device (not shown) disposed on the inner wall of the process chamber 6.

[0076] In some embodiments, the second flow rate of the introduced third gas can be precisely controlled by a mass flow controller 5 (flow control device) provided on the second gas supply line 1.

[0077] Step S13: Introduce oxidizing gas into the process chamber to perform a first oxidation-based treatment on the target film layer on the inner wall of the process chamber, causing the oxidized target film layer to crack and peel off under stress.

[0078] In some embodiments, an oxidizing gas, serving as a first gas, can be introduced into the process chamber 6 through the first gas supply port 7 to perform a first treatment on the SIPOS film layer (target film layer) deposited on the inner wall of the process chamber 6 during the SIPOS process. This oxidizes the SIPOS film layer, forming an oxidized SIPOS film layer (oxidized target film layer), causing the oxidized SIPOS film layer to crack and peel off under stress. The oxidizing gas (first gas) originates from the process gas source 3 (first gas source) and is supplied to the first gas supply port 7 through the first gas supply pipeline 4. The first gas supply port 7 and the second gas supply port 8 can overlap to form a single gas supply port. The first gas supply pipeline 4 and the second gas supply pipeline 1 can partially overlap to supply the first gas and the third gas respectively to this same gas supply port through the process gas source 3 and the auxiliary gas source 2. The exhaust gas generated during the first treatment can be discharged through the exhaust port 10 into the exhaust pipeline 12 by the suction action of the vacuum pump 13.

[0079] Before introducing the first gas for the first treatment, stop introducing the third gas (the first purging gas).

[0080] In this process, a first gas at a first flow rate is introduced at a first temperature to perform a first treatment on the SIPOS membrane layer. Utilizing the significant difference in the coefficient of thermal expansion between the oxidized SIPOS membrane layer and the inner wall of the process chamber 6—specifically, the difference in the degree of thermal expansion between the oxidized SIPOS membrane layer and the inner wall of the process chamber 6 at the high temperature during oxidation (the first temperature)—the oxidized SIPOS membrane layer develops cracks due to stress differences, forming a loose membrane structure. As the accumulated stress is released during this first treatment, the loosely structured oxidized SIPOS membrane layer peels off from the inner wall of the process chamber 6, achieving online maintenance of the process chamber 6. This effectively solves the shortcomings of traditional maintenance methods and ensures that the particle performance in subsequent SIPOS process reactions remains at a good level.

[0081] In some embodiments, the oxidizing gas (first gas) includes oxygen.

[0082] In some embodiments, the first temperature is 500°C to 650°C. For example, the first temperature can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C, or 650°C, or any value between any two of the aforementioned temperature values. However, it is not limited to these.

[0083] In some embodiments, the first flow rate is 1000 sccm to 5000 sccm. For example, the first flow rate can be 1000 sccm, 1100 sccm, 1200 sccm, 1500 sccm, 1800 sccm, 2000 sccm, 2100 sccm, 2500 sccm, 2700 sccm, 3000 sccm, 3500 sccm, 4000 sccm, 4500 sccm, 4900 sccm, or 5000 sccm, or any value between any two of the aforementioned flow rate values. However, it is not limited to these values.

[0084] Given the aforementioned temperature and gas flow rate, setting the processing time becomes crucial to ensuring the target film layer on the inner wall of the process chamber 6 is fully oxidized until it cracks and peels off due to stress, ultimately being completely removed. Both excessively long and short processing times will have adverse effects. Extensive experiments have revealed that, in a preferred embodiment, the film thickness-time ratio between the initial time T and the thickness H of the SIPOS film layer deposited on the inner wall of the process chamber 6 is as follows: H:T = 5:1 to 7:1, where H is in micrometers (µm) and T is in hours (h), i.e., the film thickness-time ratio is 5µm / h to 7µm / h. For example, the cleaning effect is particularly good when the film thickness-time ratio H:T can be 5:1, 5.1:1, 5.2:1, 5.5:1, 5.7:1, 5.9:1, 6:1, 6.1:1, 6.3:1, 6.5:1, 6.8:1, or 7:1, or any ratio between any two of the aforementioned ratios. The thickness H of the SIPOS film deposited on the inner wall of the process chamber 6 can be measured before maintenance. Considering the inconvenience of measurement inside the process chamber 6, the SIPOS film thickness on the surface of the crystal boat 9 can be measured. That is, the crystal boat 9 is removed from the process chamber 6 before maintenance, and after measurement, it is returned to the process chamber 6 for cleaning and maintenance. In another example, the film thickness can also be determined based on the previous number of processes and the thickness of a single growth. In other examples, to further improve the cleaning effect, a cleaning monitoring layer can be set on the surface of localized areas where the film is relatively easy to accumulate, such as the bottom of the process chamber 6 / or the crystal boat 9. The cleaning monitoring layer has elements different from the material of the inner wall of the process chamber 6 and the target film material, and has properties similar to the material of the process chamber 6, such as high temperature resistance and wear resistance. For example, if the inner wall of the process chamber 6 is made of silicon carbide, a small area of ​​boron carbide layer is set on the surface of the inner wall of the process chamber 6 in the area where the film layer is most likely to accumulate. During the maintenance operation, the exhaust gas is monitored in real time. When boron is detected in the exhaust gas, it means that the target film layer on the surface of the inner wall of the process chamber 6 has been completely removed, and the maintenance operation is stopped immediately. Compared with the existing methods, the monitoring accuracy is greatly improved, which can ensure the complete removal of the target film layer and avoid over-cleaning.

[0085] In some embodiments, the process cavity 6 can be heated by a heating device (not shown) disposed on the inner wall of the process cavity 6, so that the temperature inside the process cavity 6 is at a first temperature.

[0086] In some embodiments, the first flow rate of the first gas introduced can be precisely controlled by a mass flow controller 5 (flow control device) provided on the first gas supply line 4.

[0087] Step S14: Introduce a second purging gas into the process chamber to purge the process chamber a second time, and perform a second treatment on the remaining oxidized SIPOS film layer to promote its peeling.

[0088] In some embodiments, after the first process is completed, the introduction of the first gas is stopped, and a fourth gas, serving as the second purging gas, is introduced into the process chamber 6 through the second gas supply port 8 to perform a second purging of the process chamber 6, thereby discharging the residual exhaust gas in the process chamber 6 through the exhaust pipe 12. The fourth gas originates from the auxiliary gas source 2 (second gas source) and is supplied to the second gas supply port 8 through the second gas supply pipe 1. The second gas includes the fourth gas.

[0089] In some embodiments, the fourth gas includes nitrogen. Alternatively, the fourth gas includes an inert gas, such as argon.

[0090] In some embodiments, at a third temperature, a fourth gas with a third flow rate is introduced into the process chamber 6 to perform a second purging of the process chamber 6.

[0091] In some embodiments, the third temperature is 15°C to 25°C (room temperature). This third temperature of 15°C to 25°C is a general temperature used simply for purging the process chamber 6.

[0092] In some embodiments, the third flow rate is 5000 sccm to 10000 sccm. For example, the third flow rate can be 5000 sccm, 6000 sccm, 7000 sccm, 8000 sccm, 9000 sccm, or 10000 sccm, or any value between any two of the aforementioned flow rate values. However, it is not limited to this.

[0093] In some embodiments, after the first treatment, the oxidized SIPOS film on the inner wall of the process chamber 6 may not be completely peeled off, resulting in some residual oxidized SIPOS film on the inner wall of the process chamber 6. Therefore, during the second purging, a second treatment can be performed on the residual oxidized SIPOS film on the inner wall of the process chamber 6 to promote the peeling off of these residual oxidized SIPOS film layers.

[0094] In some examples, after the second processing, etching gas capable of etching the SIPOS film and its oxidized form can be introduced into the process chamber 6. Simultaneously, the products of the emitted gas are monitored to ensure that the impurity film on the inner wall of the process chamber 6 is completely removed. Following this step, a passivation step can be added to the inner wall of the process chamber 6. Passivation methods include, for example, high-temperature hydrogen passivation or oxidizing the exposed SiC inner wall of the process chamber 6, which has undergone cleaning and has had its surface SIPOS film removed, followed by high-temperature annealing. This optimizes the interfacial properties of the SiC material layer, ensuring that the SIPOS film deposited on the inner wall of the process chamber 6 in subsequent SIPOS processes remains stably attached to the surface of the inner wall before the next maintenance operation.

[0095] In some embodiments, the second process may include at least one of the following (1) to (3):

[0096] (1) The third flow rate is varied from 5000 sccm to 10000 sccm in a manner that decreases and then increases again. For example, in the early stage of the second treatment, a large flow rate can be used to blow off the remaining oxidized SIPOS film layer as soon as possible. In the middle stage, the flow rate can be reduced to reduce the long-term impact of continuous high flow rate on the internal components of the equipment and reduce the amount of nitrogen used. In the later stage, the flow rate can be increased again to check whether the remaining oxidized SIPOS film layer has been completely peeled off.

[0097] Alternatively, the third flow rate can be periodically varied between 5000 sccm and 10000 sccm by repeatedly increasing and decreasing. This causes repeated large-scale changes in the flow rate of the fourth gas, generating impact oscillations within the process chamber 6 and acting on the remaining oxidized SIPOS film layer, thereby promoting its peeling.

[0098] (2) The pressure inside the process chamber 6 is periodically changed between 1 Torr and 300 Torr by repeatedly increasing and decreasing, so as to generate pressure oscillations inside the process chamber 6 by repeatedly changing the pressure of the process chamber 6, and acting on the remaining oxidized SIPOS film layer, thereby promoting its peeling.

[0099] (3) The third temperature is periodically varied between 20℃ and 200℃ by repeatedly increasing and decreasing. This causes significant and repeated temperature fluctuations within the process chamber 6, resulting in temperature oscillations that act on the remaining oxidized SIPOS film, thereby promoting its peeling. This third temperature, which periodically varies between 20℃ and 200℃, is a specific temperature used during the second treatment, in addition to purging the process chamber 6.

[0100] The above embodiments can be used individually or in combination. For example, in some examples, the pyrolysis of the thin film on the inner wall of the process chamber 6 can be accelerated by combining temperature fluctuations and pressure oscillations.

[0101] In some embodiments, when performing the second process, the temperature inside the process cavity 6 can be reduced from the first temperature during the first process to a third temperature by a cooling device provided on the inner wall of the process cavity 6, so as to perform the second process. A heating device provided on the inner wall of the process cavity 6 can be used in conjunction with the cooling device to cause the third temperature to undergo the above-mentioned repeated changes, so as to generate a temperature oscillation effect.

[0102] In some embodiments, the third flow rate of the incoming fourth gas can be precisely controlled by a mass flow controller 5 (flow control device) provided on the second gas supply line 1, and the third flow rate can be repeatedly changed by adjusting the valve opening on the mass flow controller 5 to generate an impact oscillation effect.

[0103] In some embodiments, the vacuum pump 13 can be controlled by the automatic pressure controller 11 (automatic pressure control unit) provided on the exhaust pipe 12 to evacuate the process chamber 6 through the exhaust pipe 12, thereby achieving precise control of the pressure inside the process chamber 6. The pressure inside the process chamber 6 can be repeatedly changed by adjusting the power of the vacuum pump 13 to generate a pressure oscillation effect.

[0104] In addition, various detection methods can be used to dynamically adjust the third flow rate of the fourth gas, the pressure and temperature inside the process chamber 6. For example, by monitoring the number of particles in the exhaust gas or monitoring the surface condition of the inner wall of the process chamber 6, the cleaning effect of the second treatment on the residual SIPOS film layer on the inner wall of the process chamber 6 can be determined, and the cleaning parameters such as flow rate, pressure and temperature can be adjusted accordingly.

[0105] In some embodiments, the process chamber 6 is a vertical furnace reaction chamber capable of accommodating a crystal boat 9, which is used to load multilayer wafers for processing. As the SIPOS process reaction continues, a SIPOS film is deposited simultaneously on the inner wall of the process chamber 6 and the surface of the crystal boat 9. That is, a SIPOS film, serving as the target film, is also deposited on the crystal boat 9. Therefore, when maintaining the process chamber 6, the crystal boat 9, which is in an unloaded state, can be loaded into the process chamber 6, and the SIPOS film (target film) on the surface of the crystal boat 9 can be subjected to a first treatment, causing the SIPOS film on the surface of the crystal boat 9 to also form an oxidized SIPOS film, which will crack and peel off under stress. A second treatment can also be performed on the remaining oxidized SIPOS film on the crystal boat 9 to cause the remaining oxidized SIPOS film on the crystal boat 9 to also peel off.

[0106] In some embodiments, the inner wall material of the process chamber 6 includes silicon carbide (SiC). For example, the process chamber 6 may be a silicon carbide furnace tube.

[0107] In some embodiments, the material of the crystal boat 9 includes silicon carbide. For example, the crystal boat 9 may be a silicon carbide crystal boat.

[0108] The average coefficient of thermal expansion of silicon carbide is 4.0 × 10⁻⁶ within the temperature range of 20℃ to 1000℃. -6 / ℃. The oxygen concentration of the SIPOS film is typically 20%. At high temperatures, this oxygen concentration allows surface stress to gradually accumulate in the SIPOS film. Once a certain thickness (e.g., 15 micrometers) is deposited, numerous stress cracks will form. When oxygen is introduced at high temperatures to perform the first oxidation treatment on the SIPOS film deposited on the inner wall of process chamber 6, the SIPOS film material will gradually transform into silicon dioxide (SiO2), forming the oxidized SIPOS film (the oxidized target film). The average coefficient of thermal expansion of silicon dioxide in the range of 20℃ to 1000℃ is 0.5 × 10⁻⁶. -6 / ℃, which is significantly lower than the average thermal expansion coefficient of silicon carbide. Therefore, at the high temperature (500℃~650℃) during the first treatment, the continuous introduction of oxygen will cause a rapid accumulation of stress difference between the oxidized SIPOS film layer, i.e., the silicon dioxide-like film layer, and the silicon carbide furnace tube and silicon carbide boat. This results in almost complete release during the reaction, causing a large amount of loose film structure on the inner wall surface of the process chamber 6 to peel off, thereby achieving cleaning of the process chamber 6.

[0109] After maintaining process chamber 6, the SIPOS process can be resumed.

[0110] In some embodiments, a threshold can be set, and maintenance of the process cavity 6 can be performed when the threshold is triggered. In other words, when the threshold is triggered, it indicates that the process cavity 6 needs maintenance, thereby enabling the execution of step S11.

[0111] In some embodiments, the threshold can be determined based on the number of particles on the wafer surface monitored in each SIPOS process. If the number of particles exceeds a certain predetermined amount, and it has been ruled out that it is indeed caused by the peeling of the thin film on the inner wall surface of the process chamber 6, cleaning and maintenance should be performed as soon as possible.

[0112] In some embodiments, the threshold can be determined based on empirical data of the cumulative deposition thickness of the SIPOS film on the inner wall of the process chamber 6 when the particle count exceeds the limit due to film peeling. For example, based on multiple experimental results obtained using a microreactor semiconductor vertical furnace VF310, a cumulative deposition thickness of 15 micrometers was found to be an extreme value, so the threshold can be set to 15 micrometers.

[0113] Therefore, the need for maintenance and cleaning of the process cavity 6 can be determined based on the number of particles on the wafer surface or the cumulative thickness of the SIPOS film layer on the inner wall of the process cavity 6.

[0114] This application also provides a semiconductor device, which includes a process chamber and a maintenance system. The maintenance system performs maintenance using the process chamber maintenance method provided in any of the above embodiments. The maintenance process can be periodic or initiated as needed.

[0115] The semiconductor device of this application will now be described in detail with reference to specific embodiments and accompanying drawings.

[0116] refer to Figure 2 The semiconductor device according to this application embodiment includes a process chamber 6 and a maintenance system. The maintenance system includes a first gas supply section, a second gas supply section, and a control module disposed on the process chamber 6.

[0117] The first gas supply unit includes a first gas supply port 7. The first gas supply port 7 is located on one side of the process cavity 6, communicating with the interior of the process cavity 6, and can be positioned near the bottom of the process cavity 6. The first gas supply unit is used to introduce an oxidizing gas (such as oxygen) as a first gas into the process cavity 6 through the first gas supply port 7, so as to perform a first oxidation treatment on the SIPOS film layer (target film layer) deposited on the inner wall of the process cavity 6, so that the SIPOS film layer deposited on the inner wall of the process cavity 6 is oxidized to form an oxidized SIPOS film layer (oxidized target film layer), which cracks and peels off under stress, thereby realizing online maintenance of the process cavity 6.

[0118] The second gas supply unit includes a second gas supply port 8. The second gas supply port 8 is located on one side of the process cavity 6, communicates with the interior of the process cavity 6, and can be located near the bottom of the process cavity 6, and can be located on the same side (or nearly on the same side) as the first gas supply port 7. The second gas supply unit is used to introduce nitrogen or inert gas as a second gas into the process cavity 6 through the second gas supply port 8 to purge the interior of the process cavity 6.

[0119] The control module is used to control the on / off state of the first air supply port 7 and the second air supply port 8 to perform the first treatment and purging.

[0120] In some embodiments, the maintenance system further includes a temperature control unit, a flow control unit, and a pressure control unit.

[0121] The temperature control unit controls the temperature within the process chamber 6. The flow control unit controls the opening and closing of the first gas supply port 7 and the second gas supply port 8 to control the flow rates of the first and second gases. The pressure control unit controls the pressure within the process chamber 6.

[0122] In some embodiments, the control module is further configured to control the temperature control unit, the flow control unit, and the pressure control unit to perform: introducing a first gas at a first flow rate at a first temperature and performing a first process for a first time. Specifically, the temperature control unit can control the heating of the interior of the process chamber 6 to maintain the temperature within the process chamber 6 at the first temperature. The flow control unit controls the flow rate of the first gas introduced into the process chamber 6 through the first gas supply port 7, ensuring that the introduced flow rate of the first gas is the first flow rate. The control module also controls the duration of the first process, specifying the duration of the first process.

[0123] Further executable steps include: before introducing the first gas, a third gas at a second flow rate is introduced at a second temperature for first purging, and the introduction of the third gas is stopped during the first treatment; after the first treatment, the introduction of the first gas is stopped, and a fourth gas at a third flow rate is introduced at a third temperature for second purging. The second gas includes the third gas used as the first purging gas and the fourth gas used as the second purging gas; the third and fourth gases can be nitrogen or inert gases. The temperature inside the process chamber 6 can be maintained at a second temperature lower than the first temperature using ambient temperature or by temperature control. The flow rate of the third gas introduced into the process chamber 6 through the second gas supply port 8 is controlled by the flow control unit, ensuring that the flow rate of the third gas is the second flow rate. The temperature inside the process chamber 6 can also be cooled to a third temperature lower than the first temperature by temperature control. The flow rate of the fourth gas introduced into the process chamber 6 through the second gas supply port 8 is controlled by the flow control unit, ensuring that the flow rate of the fourth gas is the fourth flow rate. The duration of the first and second purging can also be controlled by the control module to meet the purging requirements.

[0124] It can also perform the following: During the second purging, a second treatment is applied to the oxidized SIPOS film remaining on the inner wall of the process chamber 6, based on at least one of impact oscillation, pressure oscillation, and temperature oscillation, to promote the peeling off of the remaining oxidized SIPOS film. Specifically, the temperature within the process chamber 6 can be alternately controlled by a temperature control unit to achieve temperature oscillation. The flow rate of the fourth gas can be alternately controlled by a flow control unit to achieve impact oscillation. The pressure within the process chamber 6 can be alternately controlled by a pressure control unit to achieve pressure oscillation.

[0125] It should be noted that when only the second purging is performed, the third temperature can be set to 15℃~25℃. When the second purging is performed along with a second treatment based on temperature oscillation on the oxidized SIPOS film remaining on the inner wall of the process chamber 6, the third temperature can be set to alternate between 20℃ and 200℃.

[0126] refer to Figure 2 In some embodiments, the first gas supply unit further includes a first gas supply pipeline 4. The first end (left end) of the first gas supply pipeline 4 is connected to a process gas source 3, which serves as the first gas source, and the second end (right end) of the first gas supply pipeline 4 is connected to a first gas outlet 7. The process gas source 3 is used to supply an oxidizing gas, such as oxygen, as the first gas to the process chamber 6 for first processing via the first gas supply pipeline 4 and the first gas outlet 7.

[0127] In some embodiments, the second gas supply unit further includes a second gas supply line 1. The first end (left end) of the second gas supply line 1 is connected to an auxiliary gas source 2, which serves as a second gas source, and the second end (right end) of the second gas supply line 1 is connected to a second gas supply port 8. The auxiliary gas source 2 is used to supply nitrogen or an inert gas, which serves as a third or fourth gas, to the process chamber 6 for purging via the second gas supply line 1 and the second gas supply port 8.

[0128] In some embodiments, the first gas supply port 7 and the second gas supply port 8 can overlap (merge) into a single gas supply port; the right end of the first gas supply pipeline 4 and the right end of the second gas supply pipeline 1 overlap (merge) into a single gas supply pipeline segment; and the left end of the first gas supply pipeline 4 and the left end of the second gas supply pipeline 1 are separated into two independent gas supply pipeline segments, which are respectively connected to the process gas source 3 and the auxiliary gas source 2, such as... Figure 2 As shown. In this way, the oxidizing gas such as oxygen (process gas) supplied by the process gas source 3 and the nitrogen or inert gas (auxiliary gas) supplied by the auxiliary gas source 2 will enter the same merged pipe section after passing through the separate sections of the first gas supply line 4 and the second gas supply line 1, and will be output to the process chamber 6 through the same gas supply port, ensuring the cleaning effect when purging the process chamber 6.

[0129] In some embodiments, the temperature control unit includes a heating device and a cooling device (not shown) disposed on the process chamber 6. The heating device heats the interior of the process chamber 6 to a desired first temperature or a high temperature (e.g., 200°C, 190°C, 180°C, etc.) within a third temperature range used for the second process. The cooling device cools the interior of the process chamber 6, reducing its temperature from the first temperature to a third temperature (15°C to 25°C) required for a simple second purging, or a low temperature (e.g., 20°C, 30°C, 40°C, etc.) within a third temperature range used for the second process.

[0130] In some embodiments, the heating device may be a resistance heater disposed around the sidewall of the process chamber 6.

[0131] In some embodiments, the cooling device may be a circulating water cooling or air cooling device arranged around the sidewall of the process chamber 6.

[0132] In some embodiments, the flow control unit includes flow control devices disposed on the left end of the first gas supply line 4 and the left end of the second gas supply line 1 (two separate pipe sections).

[0133] In some embodiments, the flow control device may be a mass flow controller 5. The flow rate of the first gas or the second gas supplied to the process chamber 6 can be controlled by controlling the opening degree of the valve provided in the mass flow controller 5.

[0134] In some embodiments, the pressure control unit includes a vacuum unit and an automatic pressure control unit. An exhaust port 10 is provided on the side of the process chamber 6 opposite to the first air supply port 7 / second air supply port 8. The exhaust port 10 communicates with the interior of the process chamber 6 and can be located near the bottom of the process chamber 6. The vacuum unit is connected to the first end (right end) of the exhaust pipe 12, and the second end (left end) of the exhaust pipe 12 is connected to the exhaust port 10, thereby communicating with the process chamber 6. The automatic pressure control unit is located on the exhaust pipe 12 and is used to control the vacuum unit to evacuate the process chamber 6 through the exhaust pipe 12, so that the interior of the process chamber 6 reaches the pressure required for purging, the first treatment, and the second treatment, respectively.

[0135] In some embodiments, the vacuum unit may be a vacuum pump 13. The automatic pressure control unit may be an automatic pressure controller 11.

[0136] In some embodiments, the control module is signal-connected to the heating device, cooling device, flow control device, and automatic pressure control unit to realize separate control of the first temperature, second temperature, third temperature, first flow rate, second flow rate, third flow rate, and pressure.

[0137] In some embodiments, the control module may be a host computer and / or a slave computer for controlling semiconductor devices. Alternatively, the host computer and / or slave computer may include a control module.

[0138] In some embodiments, the semiconductor equipment is a vertical furnace 100. More specifically, for example, it is a low-pressure vertical furnace for depositing SIPOS films. The process chamber 6 and exhaust pipe 12 are the process chamber 6 (furnace tube) and exhaust pipe 12 of the vertical furnace 100; the process gas source 3, auxiliary gas source 2, first gas supply pipe 4, second gas supply pipe 1, heating device, cooling device, vacuum pump 13, automatic pressure controller 11, and mass flow controller 5 contained in the maintenance system can all be reused as the process gas source 3, auxiliary gas source 2, first gas supply pipe 4, second gas supply pipe 1, heating device, cooling device, vacuum pump 13, automatic pressure controller 11, and mass flow controller 5 correspondingly provided by the vertical furnace 100 itself. In this way, the inherent facilities of the vertical furnace 100 can be fully utilized for the maintenance of the process chamber 6, making the online maintenance of the process chamber 6 simpler and more reliable, and fully ensuring the continuous and stable operation of the SIPOS process.

[0139] The aforementioned maintenance system, while maintaining the process chamber 6, is also used to simultaneously perform the first and second treatments on the SIPOS film layer (target film layer) deposited on the empty crystal boat 9 located in the process chamber 6, so as to maintain and clean the crystal boat 9.

[0140] In summary, this embodiment of the application introduces an oxidizing gas into the process chamber 6 to perform a first oxidation-based treatment on the semi-insulating oxygen-doped polycrystalline silicon (SIPOS) film deposited on the inner wall of the process chamber 6. This utilizes the significant difference in thermal expansion between the oxidized semi-insulating oxygen-doped polycrystalline silicon film and the inner wall of the process chamber 6 at the high temperature (first temperature) during oxidation. This stress difference causes cracks in the oxidized semi-insulating oxygen-doped polycrystalline silicon film, forming a loose film structure. The accumulated stress is released during the first treatment, allowing the oxidized semi-insulating oxygen-doped polycrystalline silicon film with its loose structure to peel off from the inner wall of the process chamber 6. This achieves online maintenance of the process chamber 6, effectively solving the shortcomings of traditional maintenance methods. It ensures that the particle performance in the SIPOS process reaction remains at a good level, offering advantages such as simpler, more reliable, more efficient, and faster maintenance, significantly reducing labor and material costs, and fully guaranteeing the continuous and stable operation of the SIPOS process.

[0141] The above are merely preferred embodiments of this application. These embodiments are not intended to limit the scope of protection of this application. Therefore, any equivalent changes made based on the description and drawings of this application should also be included within the scope of protection of this application.

Claims

1. A method for maintaining a process cavity, characterized in that, include: A process cavity is provided, and a target film layer is deposited on the inner wall of the process cavity. The target film layer is a semi-insulating oxygen-doped polycrystalline silicon film layer. A first gas is introduced into the process chamber to perform a first treatment on the target film layer, causing the target film layer to be oxidized to form an oxidized target film layer, which then cracks and peels off under stress. The first gas is an oxidizing gas. A second gas is introduced into the process chamber to purge the process chamber. By introducing the first gas at a first flow rate at a first temperature, the target film layer is subjected to the first treatment for a first time. By utilizing the difference between the thermal expansion coefficient of the oxidized target film layer and the thermal expansion coefficient of the inner wall of the process chamber, the oxidized target film layer is cracked due to stress difference, forming a loose film structure. The accumulated stress is released during the first treatment process, causing the oxidized target film layer with the loose film structure to peel off. The first temperature is 500℃~650℃, the first flow rate is 1000sccm~5000sccm, and the first time T and the thickness H of the target film have the following relationship: H:T=5:1~7:1, where H is in micrometers and T is in hours.

2. The process cavity maintenance method according to claim 1, characterized in that, The step of introducing a second gas into the process chamber to purge the process chamber specifically includes: Before the first gas is introduced, a third gas with a second flow rate is introduced into the process chamber at a second temperature to purge the process chamber for the first time, and the introduction of the third gas is stopped during the first process. After the first treatment is completed, the introduction of the first gas is stopped, and at the third temperature, a fourth gas with a third flow rate is introduced into the process chamber to perform a second purging of the process chamber. The second gas includes the third gas and the fourth gas.

3. The process cavity maintenance method according to claim 2, characterized in that, The oxidizing gas includes oxygen; and / or, the third gas and the fourth gas include nitrogen or an inert gas; and / or, the second temperature is 15°C to 25°C; and / or, the third temperature is 15°C to 25°C; and / or, the second flow rate is 500 sccm to 1000 sccm; and / or, the third flow rate is 5000 sccm to 10000 sccm.

4. The process cavity maintenance method according to claim 2, characterized in that, During the second purging, the oxidized target film remaining on the inner wall of the process chamber is also subjected to a second treatment to promote its peeling. The second treatment includes at least one of the following (1) to (3): (1) The third flow rate is changed from large to small and then from small to large between 5000 sccm and 10000 sccm; or, the third flow rate is changed periodically between 5000 sccm and 10000 sccm by repeatedly increasing and decreasing, so as to generate impact oscillation. (2) The pressure inside the process chamber is periodically changed between 1 Torr and 300 Torr by repeatedly increasing and decreasing to generate pressure oscillation; (3) The third temperature is periodically changed between 20°C and 200°C by repeatedly increasing and decreasing to generate temperature oscillation.

5. The process cavity maintenance method according to claim 4, characterized in that, The process chamber is a vertical furnace reaction chamber capable of accommodating a crystal boat. The target film layer is also deposited on the crystal boat. When maintaining the process chamber, the process includes performing the first treatment on the target film layer on the crystal boat in an unloaded state to form the oxidized target film layer, and performing the second treatment on the residual oxidized target film layer on the crystal boat. The inner wall material of the process chamber and the material of the crystal boat include silicon carbide.

6. A semiconductor device, characterized in that, The semiconductor equipment includes a process chamber and a maintenance system, wherein the maintenance system performs maintenance using the process chamber maintenance method as described in any one of claims 1-5, and the maintenance system includes: The first gas supply unit includes a first gas supply port, which is disposed on the process cavity. The first gas supply unit is used to introduce a first gas into the process cavity through the first gas supply port for first processing. The second air supply unit includes a second air supply port, which is disposed on the process cavity. The second air supply unit is used to introduce a second gas into the process cavity through the second air supply port for purging. The control module is used to control the on / off state of the first air supply port and the second air supply port to perform the first processing and the purging.

7. The semiconductor device according to claim 6, characterized in that, The semiconductor equipment is a vertical furnace, and the semiconductor equipment further includes: Temperature control unit, used to control the temperature inside the process chamber; The flow control unit is used to control the on / off state of the first gas supply port and the second gas supply port, so as to control the inflow rate of the first gas and the second gas. The pressure control unit is used to control the pressure inside the process chamber; The control module is also used to control the temperature control unit, the flow control unit, and the pressure control unit to perform: At a first temperature, the first gas at a first flow rate is introduced, and the first treatment is performed for a first time. Furthermore, before introducing the first gas, a third gas at a second flow rate is introduced at a second temperature for a first purging, and the introduction of the third gas is stopped during the first treatment; after the first treatment is completed, the introduction of the first gas is stopped, and a fourth gas at a third flow rate is introduced at a third temperature for a second purging; the second gas includes the third gas and the fourth gas. Furthermore, a second treatment is also performed during the second purging.

8. The semiconductor device according to claim 7, characterized in that, The first gas supply unit further includes a first gas supply pipeline, the first end of which is connected to a first gas source and the second end of which is connected to the first gas supply port. The second gas supply unit also includes a second gas supply pipeline, the first end of which is connected to a second gas source and the second end of which is connected to the second gas supply port; The first air supply port and the second air supply port coincide, and the second end of the first air supply pipeline and the second end of the second air supply pipeline coincide; The temperature control unit includes a heating device and a cooling device disposed on the process cavity; The flow control unit includes flow control devices respectively disposed at the first end of the first gas supply pipeline and the first end of the second gas supply pipeline; The pressure control unit includes a vacuum unit and an automatic pressure control unit. The vacuum unit is connected to the first end of the exhaust pipe, and the second end of the exhaust pipe is connected to the process chamber. The automatic pressure control unit is located on the exhaust pipe and is used to control the vacuum unit to evacuate the process chamber through the exhaust pipe. The control module is connected to the heating device, the cooling device, the flow control device, and the automatic pressure control unit to control the first temperature to the third temperature, the first flow rate to the third flow rate, and the pressure.

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