Gas distribution method for wafer processing equipment

Abstract

This invention provides a gas distribution method for use in wafer processing equipment, comprising: S1, providing a controller, a pressure gauge, a main pipeline, and at least one branch pipeline; the controller is connected to the pressure gauge and a valve respectively; S2, the controller controls the opening value of the valve according to the change in the average pressure value of the pressure gauge over different previous clock cycles. The gas distribution method of this invention can provide stable flow rate changes.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer processing equipment for semiconductor equipment, and particularly relates to the field of a gas distribution device and method for wafer processing equipment. Prior Art

[0002] A semiconductor wafer processing equipment is a device for processing wafers, which can perform etching, thin film deposition, cleaning, etc. on the wafer surface. All the above-mentioned wafer processing equipment needs to introduce process gases during the process. However, the control of process gases (such as flow rate and velocity) is crucial for the process results. In the prior art, a mass flow controller (MFC) is installed in the gas pipeline to control the process gases.

[0003] However, during the process, when adjusting the flow rate of the process gas, due to sudden flow rate changes, the process gas will become unstable. This phenomenon is more serious when there are multiple zones at the inlet end due to the mutual influence between the zones. How to quickly respond to the flow rate changes and reduce the impact of such changes on the process quality has become an urgent problem to be solved. Summary of the Invention

[0004] The purpose of the present invention is to provide a gas distribution device and a wafer processing equipment for solving the problem of stable control of air flow.

[0005] In order to achieve the above purposes, the present invention is realized through the following technical solutions:

[0006] The present invention provides a gas distribution method applied to wafer processing equipment, including:

[0007] S1. Provide a controller, a pressure gauge, a main pipeline, and at least one branch pipeline. One end of each branch pipeline is connected to the main pipeline, and the other end of each branch pipeline is respectively connected to a zone of an air inlet part of a chamber of the wafer processing equipment; a valve is arranged on the branch pipeline; the pressure gauge is arranged upstream of the valve for detecting the pressure value upstream of the valve; the controller is respectively connected to the pressure gauge and the valve;

[0008] S2. The controller controls the opening value of the valve according to the change of the average value of the pressure values in different previous clock cycles of the pressure gauge.

[0009] Optionally, in the step S2, controlling the opening value of the valve to be: Mean calculation step: The controller obtains the first average pressure based on the pressure values in the previous N clock cycles, and obtains the second average pressure based on the pressure values in the previous M clock cycles, where N and M are both positive integers, and N > M. Judgment step: The controller judges whether the first average pressure and the second average pressure are both greater than the first threshold. Adjustment step: If the judgment result is yes, then perform the action of adjusting the opening value of the valve and enter the adjustment stage.

[0010] Optionally, in the step S2, in the adjustment stage, there is also a continuous judgment step, and the controller controls whether to continue to adjust the opening value of the valve according to the change of the average value of the pressure values in different previous clock cycles of the pressure gauge.

[0011] Optionally, the number of previous clock cycles in the adjustment stage is greater than the number of previous clock cycles before the adjustment stage.

[0012] Optionally, controlling whether to continue to adjust the opening value of the valve is as follows: In the adjustment stage, the controller obtains the third average pressure based on the pressure values in the previous N1 clock cycles, and obtains the fourth average pressure based on the pressure values in the previous M1 clock cycles. The controller judges whether the third average pressure and the fourth average pressure are both greater than the second threshold. If so, then perform the action of continuing to adjust the opening value of the valve; where N1 and M1 are both positive integers, N1 > M1, N1 > N, and M1 > M.

[0013] Optionally, the second threshold is greater than the first threshold.

[0014] Optionally, in the step S2, after the judgment step and / or the continuous judgment step, there is also a delay and re-judgment step.

[0015] Optionally, the delay and re-judgment step is as follows: After a delay time Δt, re-judge whether the first average pressure and the second average pressure are both greater than the first threshold. If so, perform the action of adjusting the opening value of the valve. And / or, after a delay time Δt, re-judge whether the third average pressure and the fourth average pressure are both greater than the second threshold. If so, perform the action of adjusting the opening value of the valve.

[0016] Optionally, in the step S2, in the judgment step and / or the continuous judgment step, if the judgment result is no, then enter the flow ratio control mode.

[0017] Optionally, in step S2, after the judgment step and / or the continuous judgment step, if the judgment result is yes, then perform the delayed re-judgment step; if the judgment result is no, then enter the flow ratio control mode.

[0018] Optionally, both the first threshold and the second threshold correspond one-to-one to different total flow rates of the main pipeline and different flow ratios of each branch pipeline.

[0019] Optionally, the regions of the chamber are three.

[0020] Compared with the prior art, the present invention has the following advantages: The pressure gauge of the present invention can monitor the pressure upstream of the valve in real time. When the flow rate is switched, the pressure gauge can monitor the change in pressure. The controller adjusts the opening value of the valve according to the change in pressure, thereby reducing the pressure change at the pressure gauge, and thus quickly stabilizing the flow rate of the branch pipeline. In addition, the present invention controls the opening value of the valve by the change in the average value of the pressure values in different previous clock cycles, and can more accurately judge the change in pressure. Brief description of the drawings

[0021] In order to more clearly illustrate the technical solution of the present invention, the drawings required for description will be briefly introduced below. Obviously, the drawings in the following description are an embodiment of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative labor:

[0022] FIG. 1 is a schematic structural diagram of a wafer processing apparatus provided by the present invention; FIG. 2 is another schematic structural diagram of a wafer processing apparatus provided by the present invention; FIG. 3 is a corresponding list of the first threshold, the second threshold, the total flow rate, and the flow ratio provided by the present invention; FIG. 4 is another schematic structural diagram of a wafer processing apparatus provided by the present invention; FIG. 5 is another schematic structural diagram of a wafer processing apparatus provided by the present invention; FIG. 6 is a schematic diagram of a gas distribution method provided by the present invention; FIG. 7 is a flowchart of a gas distribution method provided by the present invention; FIG. 8 is another flowchart of a gas distribution method provided by the present invention. Embodiment

[0023] The solution proposed by the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features, and advantages of the present invention more obvious and understandable, please refer to the drawings. It should be known that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed by the present invention.

[0024] Figure 1 shows the wafer processing equipment of the present invention. As shown in Figure 1, the wafer processing equipment includes: a chamber 200, a source 300, and a gas distribution device 100. The chamber 200 is used for performing semiconductor process on wafers; the source 300 is connected to the chamber 200 through the gas distribution device 100; the source is used for storing process gases. Optionally, the chamber 200 is at least one of an epitaxial chamber, a rapid thermal processing chamber, a CVD chamber, and an etching chamber. Different chambers correspond to different processings. For example, the epitaxial chamber is used for performing epitaxial process, the rapid thermal processing chamber is used for performing rapid annealing process, and the etching chamber is used for performing etching process, including but not limited to silicon etching, dielectric etching, or metal etching. The present invention takes the epitaxial chamber as an example.

[0025] The chamber 200 shown includes a chamber body, an air inlet member 201, and an exhaust member 203. The chamber body is used for accommodating wafers and performing semiconductor process on wafers; the air inlet member 201 is arranged at one end of the chamber body, and the exhaust member 203 is arranged at the other end of the chamber body. The positions of the air inlet member 201 and the exhaust member 203 are opposite on the horizontal plane. Optionally, the air inlet member 201 includes at least two separated areas, and the gas control between each area is independent; preferably, the air inlet member is separated into three areas, namely area A, area B, and area C. Therefore, the process gas is divided into three paths on the surface of the wafer W, and the flow rates of the three paths of process gas can be independently controlled, so as to control the film deposition quality of the epitaxial layers in three areas on the surface of the wafer W.

[0026] The wafer processing equipment further includes a pump 205, which is connected to the chamber 200 and is used to control the process pressure of wafer processing in the chamber and discharge the process gas after processing from the chamber. Specifically, the pump 205 is connected to the exhaust member 203 through a pipeline.

[0027] During the epitaxial process, the process gas is distributed from the source 300 through the gas distribution device 100 into different regions of the inlet member 201. The gas distribution device 100 can independently control the gas flow between different regions in the inlet member 201. The process gases between different regions are independently controlled by the gas distribution device 100, so as to form a stable flow field in multiple regions on the surface of the wafer W. Under the action of thermal radiation, the process gas decomposes, and a uniform epitaxial layer film grows on the wafer surface. Finally, under the control of the pump 205, the process gas after processing is extracted from the chamber through the exhaust member 203.

[0028] Of course, the gas distribution device 100 is also applicable to other wafer processing equipment, especially in wafer processing equipment with multiple-region inlets, such as etching, CVD, RTP, etc.

[0029] FIG. 1 shows the gas distribution device of the present invention. As shown in the dashed box in FIG. 1, the gas distribution device 100 includes: a main pipeline 101, branch pipelines 103, a pressure gauge 104, and a controller 105.

[0030] The main pipeline 101 is connected to the source 300 of the process gas;

[0031] There are at least two branch pipelines 103. One end of each branch pipeline is connected to the main pipeline 101, and the other end of each branch pipeline is respectively connected to a region of the inlet member 201 of the chamber of the wafer processing equipment; the branch pipeline includes a valve 102, and the valve is arranged in the branch pipeline; optionally, there are 3 branch pipelines 103. Correspondingly, there are also three regions of the inlet member, and the 3 branch pipelines 103 are connected in parallel and are respectively connected to regions A, B, and C of the inlet member 201.

[0032] The pressure gauge 104 is arranged upstream of the valve 102 and is used to detect the pressure value upstream of the valve. The gas distribution device further includes a distribution pipeline 109, and the main pipeline is respectively connected to the branch pipelines through the distribution pipeline 109. The main pipeline 101 includes a mass flow controller 116, and the mass flow controller is arranged in the main pipeline and is used to control the flow rate of each process gas in the main pipeline 101.

[0033] The controller 105 is respectively connected to the pressure gauge 104 and the valve 102, and is used to control the opening value of the valve according to the change of the pressure value of the pressure gauge. Wherein, FIG. 2 shows a schematic structural diagram of the controller. As shown in FIG. 2, the controller 105 includes a connected calculation module, a judgment module, an execution module and a storage module. Optionally, the controller 105 is used to control the opening value of the valve according to the change of the average value of the pressure values in different previous clock cycles of the pressure gauge 104. Among them, the average values of different pressure values can be two. By judging the increase of the pressure value and thus adjusting the opening value, the problem of unstable process gas caused during flow switching can be well suppressed.

[0034] In some embodiments, specifically, the controlling the opening value of the valve is as follows: The controller 105 obtains a first average pressure according to the pressure values in the previous N clock cycles, and obtains a second average pressure according to the pressure values in the previous M clock cycles. The controller judges whether the first average pressure and the second average pressure are both greater than a first threshold value. If so, it performs the action of adjusting the opening value of the valve; wherein, both N and M are positive integers, and N>M; the clock cycle is the sampling cycle of the pressure gauge 104, and the previous M clock cycles are the previous M clock cycles of the current sampling cycle. Taking M = 3 as an example, the second average pressure obtained from the pressure values in the previous M clock cycles = (the pressure value of the previous 1 clock cycle of the current clock cycle + the pressure value of the previous 2 clock cycles of the current clock cycle + the pressure value of the previous 3 clock cycles of the current clock cycle) / 3. Similarly, the first average pressure can be obtained. Optionally, 10≤N≤35, 5≤M≤20. By judging with two average values, the situation where the pressure value becomes larger and then drops due to accidental factors can be avoided, misjudgment is avoided, and the accuracy of judgment is improved.

[0035] The first threshold value is an empirical value obtained through experiments, and the first threshold value corresponds one-to-one to different total flow rates of the main pipeline 101 and different flow ratios of each branch pipeline 103, that is, the first threshold values corresponding to different total flow rates and flow ratios are different. As shown in FIG. 3, only as an example, rather than a specific limitation, it can be seen that as the total flow rate and the flow ratio change, the first threshold value also changes. In the above steps, the controller first determines the first threshold value according to the total flow rate and the flow ratio, and then judges the relationship between the first average pressure and the second average pressure and the first threshold value. The advantage of this is that the problem of unstable process gas in different situations can be better suppressed, and the judgment is more accurate.

[0036] Once the controller determines that the first average pressure and the second average pressure are both greater than the first threshold value, it starts to execute the action of adjusting the opening value of the valve, that is, enters the adjustment stage. During the period of adjusting the opening value of the valve (i.e., the adjustment stage), the controller 105 is also used to continuously judge, that is, to control whether the valve continues to adjust the opening value according to the change of the average value of the pressure values in different previous clock cycles of the pressure gauge; among them, the previous multiple clock cycles start from the current clock cycle; the average values of different pressure values can be two.

[0037] Preferably, in the adjustment stage, the previous multiple clock cycles are greater than the previous multiple clock cycles before adjusting the opening value of the valve, that is: in the adjustment stage, the two clock cycles are N1 and M1 respectively, and both N1 and M1 are positive integers, N1>M1, N1>N, M1>M.

[0038] Specifically, controlling whether the valve continues to adjust the opening value is: during the period when the controller adjusts the opening value of the valve, it obtains the third average pressure according to the pressure values in the previous N1 clock cycles, and obtains the fourth average pressure according to the pressure values in the previous M1 clock cycles. The controller judges whether the third average pressure and the fourth average pressure are both greater than the second threshold value. If so, it executes the action of continuing to adjust the opening value of the valve; among them, the second threshold value is greater than the first threshold value. Similar to the first threshold value, the second threshold value is also an empirical value obtained through experiments, and the second threshold value corresponds one-to-one to different total flow rates of the main pipeline 101 and different flow ratios of each branch pipeline 103, that is, the first threshold values corresponding to different total flow rates and flow ratios are different. As shown in Figure 3, it is only an example, not a specific limitation.

[0039] In some preferred embodiments, it further includes a delay re-judgment step. After the controller judges whether two average pressures (the first average pressure and the second average pressure, or the third average pressure and the fourth average pressure) are both greater than the threshold value (the first threshold value or the second threshold value), it does not immediately execute the action of adjusting the opening value of the valve. After a delay time Δt, it re-judges whether two average pressures (the first average pressure and the second average pressure, or the third average pressure and the fourth average pressure) are both greater than the threshold value (the first threshold value or the second threshold value). Only when both judgments are established, does it execute the action of adjusting the opening value of the valve. Among them, the delay time Δt is 1 to 5 clock cycles. This step can further determine that the increase in the pressure value is not accidental, and improves the accuracy of the judgment.

[0040] Optionally, the calculation module is used to calculate the average pressure, that is, to calculate the first average pressure, the second average pressure, the third average pressure, and the fourth average pressure. The judgment module is used to judge whether the average pressure is greater than the threshold value, that is, to judge whether the first average pressure and the second average pressure are greater than the first threshold value, and whether the third average pressure and the fourth average pressure are greater than the second threshold value. The controller further includes an execution module, and the execution module is used to execute the action of adjusting the opening value of the valve. The controller further includes a storage module, and the storage module is used to store the threshold values, that is, to store the first threshold value and the second threshold value.

[0041] Figure 4 shows another embodiment. As shown in Figure 4, the pressure gauge 104 is arranged on at least one of the branch pipelines. Preferably, the pressure gauge 104 is arranged on each branch pipeline, and the pressure value for calculating the average value is taken from the pressure gauge 104 on the branch pipeline closest to the main pipeline 101, which can ensure the minimum fluctuation. At the same time, when one pressure gauge 104 is damaged, the pressure value of other pressure gauges 104 can also be used.

[0042] Figure 5 shows another embodiment. As shown in Figure 5, the branch pipeline further includes a flow meter 106. The flow meter 106 is arranged upstream of the valve 102, and the pressure gauge 104 is arranged upstream of the flow meter. The flow meter is used to monitor the flow rate of the corresponding branch pipeline 103 in real time. Optionally, the pressure gauge 104 can also be arranged on the main pipeline 101.

[0043] Optionally, there is at least one main pipeline 101. Preferably, there are 4 main pipelines 101; and each main pipeline 101 is respectively connected to the source 300 of the corresponding process gas. The process gas includes a silicon source, a germanium source, a carrier gas, and a doping gas; the silicon source, the germanium source, the carrier gas, and the doping gas are respectively placed in the corresponding source 300, and then are gathered and mixed through 4 main pipelines 101.

[0044] Figure 6 shows a schematic diagram of the gas distribution method. The present invention also provides a gas distribution method applied to a wafer processing device. As shown in Figure 6, the method includes:

[0045] S1. Provide a controller, a pressure gauge, a main pipeline, and at least one branch pipeline. One end of each branch pipeline is connected to the main pipeline, and the other end of each branch pipeline is respectively connected to a corresponding area of an air inlet member of a chamber of the wafer processing equipment; a valve is provided on the branch pipeline; the pressure gauge is provided upstream of the valve for detecting the pressure value upstream of the valve; the controller is respectively connected to the pressure gauge and the valve; optionally, the controller, the pressure gauge, the main pipeline, and at least one branch pipeline are the gas distribution device 100 described above.

[0046] S2. The controller controls the opening value of the valve according to the change of the average value of the pressure values in different previous clock cycles of the pressure gauge.

[0047] Wherein, as shown in Figure 7, in step S2, the steps of controlling the opening value of the valve include: Average value calculation step: The controller obtains a first average pressure according to the pressure values in the previous N clock cycles, and obtains a second average pressure according to the pressure values in the previous M clock cycles, where N and M are both positive integers, and N>M; Judgment step: The controller judges whether the first average pressure and the second average pressure are both greater than a first threshold value; Adjustment step: If the judgment result is yes, then perform the action of adjusting the opening value of the valve and enter the adjustment stage.

[0048] Optionally, in step S2, in the adjustment stage, there is also a continuous judgment step, and the controller controls whether to continue to adjust the opening value of the valve according to the change of the average value of the pressure values in different previous clock cycles of the pressure gauge.

[0049] The control of whether to continue to adjust the opening value of the valve is as follows: In the adjustment stage, the controller obtains a third average pressure according to the pressure values in the previous N1 clock cycles, and obtains a fourth average pressure according to the pressure values in the previous M1 clock cycles. The controller judges whether the third average pressure and the fourth average pressure are both greater than a second threshold value. If so, then perform the action of continuing to adjust the opening value of the valve; where N1 and M1 are both positive integers, and N1>M1. Optionally, the previous multiple clock cycles in the adjustment stage are greater than the previous multiple clock cycles before the adjustment stage, that is: N1>N, M1>M. Preferably, the second threshold value is greater than the first threshold value. In the adjustment stage, the adjustment of the opening itself will affect the fluctuation of the pressure value. Therefore, N1>N, M1>M, and the second threshold value is larger, which is beneficial to maintaining the stability of the flow rate in the adjustment stage.

[0050] Optionally, as shown in FIG. 8, in step S2, after the determination step and / or the continuous determination step, a delayed re-determination step is further included. That is, the delayed re-determination step can be only after the determination step or after the continuous determination step, or after both the determination step and the continuous determination step.

[0051] Specifically, the delayed re-determination step is as follows: After the determination step, after a delay time Δt, re-determine whether the first average pressure and the second average pressure are both greater than the first threshold value. If so, perform the action of adjusting the opening value of the valve; And / or, after the continuous determination step, after a delay time Δt, re-determine whether the third average pressure and the fourth average pressure are both greater than the second threshold value. If so, perform the action of continuously adjusting the opening value of the valve.

[0052] Optionally, in step S2, in the determination step and / or the continuous determination step, if the determination result is negative, enter the flow ratio control mode. If the determination result is positive, enter the delayed re-determination step.

[0053] Optionally, in step S2, after the determination step and / or the continuous determination step, if the determination result is positive, perform the delayed re-determination step; if the determination result of the delayed re-determination step is negative, enter the flow ratio control mode. If the determination result of the delayed re-determination step is positive, enter the adjustment step.

[0054] The above-mentioned flow ratio control, that is, the step of adjusting the opening is ended, and the distribution of the process gas is controlled by the flow ratio of each branch pipeline 103.

[0055] The pressure gauge 104 of the present invention can monitor the pressure upstream of the valve in real time. When the flow is switched, the pressure gauge 104 can monitor the change of the pressure. The controller adjusts the opening value of the valve according to the change of the pressure, so as to reduce the pressure change at the pressure gauge, and thus quickly stabilize the flow of the branch pipeline.

[0056] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or apparatus. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising the element. Additionally, the term "connected" in this text means that A and B are directly connected, or that A and B are indirectly connected, such as A and B being connected through C, or even through more components such as C and D. The connection between A and B can be integral or separable, detachable or fixed. The term "optional" in this text means that this technical feature can be combined or not combined with any feature in the text.

[0057] Although the content of the present invention has been introduced in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and substitutions to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended patent application scope.

[0058] 100: Gas distribution device 101: Main pipeline 102: Valve 103: Branch pipeline 104: Pressure gauge 105: Controller 106: Flow meter 109: Distribution pipeline 116: Mass flow controller 200: Chamber 201: Inlet part 203: Exhaust part 205: Pump 300: Source A, B, C: Zones W: Wafer S1, S2: Steps

Claims

1. A gas distribution method applied to wafer processing equipment, wherein, include: S1. A controller, a pressure gauge, a main pipeline, and at least one branch pipeline are provided. One end of each branch pipeline is connected to the main pipeline, and the other end of each branch pipeline is connected to a corresponding area of ​​the air inlet of the chamber of the wafer processing equipment. A valve is installed on each branch pipeline. The pressure gauge is installed upstream of the valve to detect the pressure value upstream of the valve. The controller is connected to both the pressure gauge and the valve. S2. The controller controls the valve opening value based on the change in the average pressure value of the pressure gauge over different previous clock cycles. In step S2, controlling the valve opening value involves: an average value calculation step, where the controller obtains a first average pressure based on the pressure values ​​of the previous N clock cycles and a second average pressure based on the pressure values ​​of the previous M clock cycles, where N and M are both positive integers, and N > M; a judgment step, where the controller judges whether the first average pressure and the second average pressure are simultaneously greater than a first threshold; and an adjustment step, where if the judgment result is yes, the controller adjusts the valve opening value, entering the adjustment stage.

2. The gas distribution method for a wafer processing apparatus as described in claim 1, wherein, In step S2, during the adjustment phase, the judgment step is continued, and the controller controls whether the valve continues to adjust the opening value based on the change in the average pressure value of the pressure gauge over different previous multiple clock cycles.

3. The gas distribution method for a wafer processing apparatus as described in claim 2, wherein, The first few clock cycles of the adjustment phase are greater than the first few clock cycles before the adjustment phase.

4. The gas distribution method for a wafer processing apparatus as described in claim 2, wherein, Controlling whether the valve continues to adjust the opening value: During the adjustment phase, the controller obtains a third average pressure based on the pressure values ​​of the previous N1 clock cycles and a fourth average pressure based on the pressure values ​​of the previous M1 clock cycles. The controller determines whether the third average pressure and the fourth average pressure are simultaneously greater than a second threshold. If so, it executes the action of continuing to adjust the valve opening value; where N1 and M1 are both positive integers, N1 > M1, N1 > N, M1 > M.

5. The gas distribution method for a wafer processing apparatus as described in claim 4, wherein, The second threshold is greater than the first threshold.

6. The gas distribution method for a wafer processing apparatus as described in claim 2, wherein, In step S2, after the judgment step and / or the continuous judgment step, a delayed re-judgment step is also included.

7. The gas distribution method for a wafer processing apparatus as described in claim 6, wherein, The delayed judgment step is as follows: after a delay time Δt, it is determined whether the first average pressure and the second average pressure are simultaneously greater than the first threshold. If so, the valve opening value is adjusted. And / or, after a delay time Δt, it is determined whether the third average pressure and the fourth average pressure are simultaneously greater than the second threshold. If so, the valve opening value is adjusted.

8. The gas distribution method for a wafer processing apparatus as described in claim 7, wherein, In step S2, if the judgment result is negative in the judgment step and / or continuous judgment step, the flow ratio control mode is entered.

9. The gas distribution method for a wafer processing apparatus as described in claim 7, wherein, In step S2, after the judgment step and / or the continuous judgment step, if the judgment result is yes, the delayed re-judgment step is performed; if the judgment result is no, the flow ratio control mode is entered.

10. The gas distribution method for a wafer processing apparatus as described in claim 5, wherein, Both the first threshold and the second threshold correspond one-to-one with the different total flow rates of the main pipeline and the different flow rate ratios of each of the branch pipelines.

11. The gas distribution method for a wafer processing apparatus as described in claim 1, wherein, The chamber has three zones.

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