Process window determination method, semiconductor processing method, and apparatus

Abstract

The application discloses a process window determination method, a semiconductor processing method and equipment, and relates to the technical field of semiconductor manufacturing. In view of the problems of time loss and poor exhaust mode compatibility caused by the fact that the prior art relies on pressure gauge reading stability to determine the process window, the application determines the process window start time by recording the switching period of the measured pressure between two stable pressures and combining the flow switching instruction time; further, the pre-calibration stage and the process stage are distinguished, the switching period is obtained in the pre-calibration stage, and a database is established, and in the process stage, the parameters are directly reused for open-loop operation, and multiple exhaust modes such as fixed opening of the vacuum valve and feedback regulation are compatible. The application can start the process without waiting for the pressure gauge reading to be completely stable, effectively increases the process window time, significantly improves the equipment productivity and process adaptability, and is suitable for rapid pressure switching cyclic semiconductor processes such as atomic layer etching and atomic layer deposition.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, specifically to a process window determination method, a semiconductor processing method, and equipment. Background Technology

[0002] In semiconductor manufacturing processes, such as atomic layer etching (ALE), the pressure inside the chamber needs to be switched rapidly between different target values, and the process can only begin after the pressure has basically stabilized to ensure the consistency and repeatability of the process.

[0003] In existing technologies, pressure gauges (also known as vacuum gauges) are typically used to measure the pressure within a chamber, as illustrated in Chinese patent applications CN121122993A, CN121096914A, CN121790264A, CN121768935A, and CN121687820A. To protect the pressure gauge from damage caused by high-pressure impacts, high temperatures, or corrosive gases during the process, and to prevent contamination of the pressure gauge by reaction byproducts, the pressure gauge is generally installed outside the chamber and connected to it via a connecting channel. Due to the presence of the connecting channel and the pressure gauge's own volume, there is a certain delay in the pressure gauge's measurement of pressure changes within the chamber. The longer the connecting channel, the more pronounced the delay. Although the delay can be reduced by shortening the length of the connecting channel, the connecting channel always has a certain volume, which is difficult to eliminate due to limitations imposed by the chamber wall thickness and the pressure gauge's own installation and connection requirements. Furthermore, commercially available pressure gauges for process chambers generally have a certain pressure measurement response delay, which is also difficult to eliminate.

[0004] When process pressure changes slowly, or when the control logic is not sensitive to pressure fluctuations, this lag in pressure measurement is acceptable. However, when process pressure needs to be switched rapidly, especially when the switching time and the pressure gauge response time are on the same order of magnitude, this lag becomes unacceptable. For example, in the ALE process, the pressure inside the chamber needs to switch rapidly between high and low pressure repeatedly. After each switch, it is necessary to wait for the pressure to stabilize before the process can begin; that is, the pressure stabilization period corresponds to the process window period. If the pressure stabilization status is determined by the stability of the pressure gauge reading, then due to the measurement delay of the pressure gauge, the pressure inside the chamber may have actually stabilized for some time, but the pressure gauge reading has not yet stabilized. This leads to a loss of process window time. For processes that require hundreds or even thousands of cycles, the loss of tens of milliseconds of process window time per cycle will significantly reduce the equipment's capacity. At the same time, the lag in pressure feedback may cause the process to operate in a non-ideal pressure environment. That is, the actual pressure inside the process chamber has changed, but the pressure gauge has not reported this change in time, which will cause the process to be carried out under non-ideal pressure conditions, thereby reducing product yield.

[0005] Therefore, there is an urgent need for a solution that can more quickly determine the stable pressure state within the chamber in order to solve the aforementioned problems in the existing technology. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a process window determination method, semiconductor processing method and equipment. The process window is determined by recording the complete pressure switching time period and the flow switching time, without waiting for the pressure gauge reading to stabilize. It is also compatible with multiple exhaust control modes, effectively improving the process window utilization rate and equipment capacity.

[0007] To achieve the above objectives, the present invention provides a method for determining a process window, comprising: A process chamber is provided, the process chamber is connected to an air inlet device, an exhaust device and a pressure gauge, the air inlet device controls the flow rate of the process gas supplied into the process chamber, the exhaust device is used to evacuate the process chamber, and the pressure gauge is used to measure the pressure inside the process chamber and output the measured pressure. The intake and exhaust devices are configured to operate in a preset mode, which includes alternately supplying a first flow rate gas and a second flow rate gas, so that the measured pressure is maintained at a first pressure under the first flow rate gas to perform a first process, and maintained at a second pressure under the second flow rate gas to perform a second process. Record the first switching time period when the measured pressure switches from the second pressure to the first pressure; The start time of the process window for the first process is determined based on the first time when the second flow gas is switched to the first flow gas and the first switching period.

[0008] In some embodiments, the start time of the process window of the first process is: a second time obtained after the first switching period, starting from the first time when the second flow gas is switched to the first flow gas.

[0009] In some embodiments, the termination time of the process window of the first process is the third time when the first flow gas is switched to the second flow gas.

[0010] In some embodiments, the method further includes: recording a second switching period during which the measured pressure changes from the first pressure to the second pressure; the start time of the process window for the second process is a fifth time obtained after the second switching period, starting from the fourth time when the first flow gas is switched to the second flow gas.

[0011] In some embodiments, the process window termination time of the second process is the sixth time after the second flow gas is switched to the first flow gas.

[0012] In some embodiments, the start time of the process window of the first process is: a second time obtained from the first time, after the sum of the first switching period and a preset safety margin.

[0013] The present invention also provides a semiconductor processing method, including a pre-calibration stage and a process stage. The pre-calibration stage executes the process window determination method described in any of the above claims to obtain the start time of the process window. The process stage configures the air intake device and the air exhaust device to operate in the preset mode and starts the processing at the start time.

[0014] In some embodiments, the pre-calibration stage is performed in advance to establish a database of switching time periods corresponding to different process conditions. The process conditions include at least one of a first flow gas, a second flow gas, an exhaust device control mode, and a process gas type. During the process, the corresponding first switching time period is retrieved from the switching time period database according to the current process conditions.

[0015] In some embodiments, the exhaust device control mode includes: maintaining the target opening degree unchanged during the pre-calibration stage and the process stage, and / or adjusting the fluctuation by a preset amplitude based on the target opening degree during the pre-calibration stage and the process stage.

[0016] The present invention also provides a semiconductor processing apparatus, comprising: a process chamber having a base therein for supporting a substrate; an inlet device connected to the process chamber for controlling the type and flow rate of process gas supplied to the process chamber; an exhaust device connected to the process chamber for evacuating the process chamber; a pressure gauge connected to the process chamber for measuring the pressure inside the process chamber and outputting the measured pressure; and a controller communicatively connected to the inlet device, the exhaust device, and the pressure gauge, wherein the controller is configured to execute the semiconductor processing method described in any of the preceding embodiments.

[0017] In some embodiments, the device further includes a radio frequency (RF) component for exciting plasma within the process cavity to process the substrate, the controller being communicatively connected to the RF component and configured to turn on the RF component at the start of a process window and turn off the RF component at the end of a process window.

[0018] This invention configures the intake and exhaust devices to operate in a preset mode, fixing their control modes. The complete switching period between two stable pressure values ​​in the process chamber is an inherent characteristic of the system, determined solely by process conditions and highly repeatable. By recording this complete switching period, the actual stable pressure time in the chamber can be accurately predicted directly based on the flow switching command, without waiting for the pressure gauge reading to enter the stable range, thus maximizing the utilization of effective process time.

[0019] This invention records the complete switching time between two stable pressures and determines the start time of the process window by combining the flow switching command time. The process can be started without waiting for the pressure gauge reading to be completely stable, which effectively increases the effective process window time and improves equipment capacity.

[0020] By distinguishing between the pre-calibration stage and the process stage, the pre-calibration stage obtains the process window start time parameter, and the process stage directly reuses the parameter for operation, which simplifies the control logic of the process and improves production efficiency.

[0021] It also provides equipment capable of performing the aforementioned semiconductor processing methods, enabling accurate determination and efficient control of the process window, and ensuring the consistency and stability of the process. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope of the present invention. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the process window determination method according to an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the relationship between measured pressure, flow rate, and process window timing in an embodiment of the present invention. Figure 3 This is a schematic diagram of the semiconductor processing device structure according to an embodiment of the present invention.

[0024] Explanation of markings in the diagram: W-Substrate; 100-Process chamber; 101-Base; 200-Inlet device; 201-First inlet valve; 202-Second inlet valve; 203-Mass flow controller; 300-Exhaust device; 301-Vacuum valve; 302-Vacuum pump; 400-Pressure gauge; 500-Connection channel; 600-Controller; 800-RF component. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] In existing technologies, the delay in pressure measurement mainly comes from two aspects: first, the transmission delay of gas in the connecting channel, as the pressure wave needs a certain amount of time to propagate from the chamber to the pressure gauge end; and second, the mechanical or thermal response delay of the pressure gauge sensor itself. These two delays are significantly amplified in low-vacuum rapid switching scenarios.

[0027] To avoid inaccurate process pressure, the process window end signal uses the flow switching time point. This prevents the process from operating under suboptimal pressure conditions due to pressure changes within the chamber not being promptly reported by the pressure gauge, thus avoiding a decrease in yield. However, this shortens the process window, necessitating an extension of the overall process time to meet the window requirements, thereby reducing process efficiency.

[0028] Therefore, embodiments of the present invention provide a method for determining a process window. Please refer to [link / reference]. Figure 1 This includes the following steps: S10: A process chamber 100 is provided, which is connected to an air inlet device 200, an exhaust device 300 and a pressure gauge 400. The air inlet device 200 controls the flow rate of the process gas supplied to the process chamber 100, the exhaust device 300 is used to evacuate the process chamber 100, and the pressure gauge 400 is used to measure the pressure inside the process chamber 100 and output the measured pressure.

[0029] For example, the intake device 200 includes multiple intake valves and a mass flow controller 203, which can independently control the type and flow rate of different process gases; the exhaust device 300 includes a vacuum valve 301 and a vacuum pump 302, which can be a turbomolecular pump, a dry pump or a combination thereof; the pressure gauge 400 is installed on the side wall of the process chamber 100 through the connection channel 500 for outputting real-time measured pressure.

[0030] S20: The intake device 200 and the exhaust device 300 are configured to operate in a preset mode. The preset mode includes alternately supplying a first flow gas and a second flow gas, so that the measured pressure is maintained at a first pressure under the first flow gas to perform a first process, and maintained at a second pressure under the second flow gas to perform a second process.

[0031] When the intake and exhaust reach dynamic equilibrium, the measured pressure will be maintained at a first pressure under the first flow rate gas and at a second pressure under the second flow rate gas, corresponding to the operating pressures of the first and second processes, respectively. By using a fixed preset mode, the repeatability of the pressure switching process is ensured, providing a stable basis for subsequent window determination and process operation.

[0032] S30: Record the first switching period when the measured pressure changes from the second pressure to the first pressure.

[0033] The first switching period fully covers the entire process of pressure propagation delay, pressure gauge response delay, and pressure transition stabilization, accurately reflecting the inherent characteristics of system pressure switching. It eliminates the need for additional decomposition of delay components, simplifying the measurement logic.

[0034] S40: Determine the start time of the process window of the first process based on the first time when the second flow gas is switched to the first flow gas and the first switching period.

[0035] By combining the timing of flow switching commands with the pressure switching period, the starting point of the process window can be determined without waiting for the pressure gauge reading to enter the stable range, effectively eliminating the redundant stabilization waiting time in existing technologies and improving production capacity.

[0036] In one embodiment, the start time of the process window of the first process is: the second time obtained after a first switching period, starting from the first time when the second flow gas is switched to the first flow gas.

[0037] This embodiment directly uses the complete switching period to calculate the starting point of the window, maximizing the use of effective process time, and is suitable for production scenarios with stable process conditions and high system response consistency.

[0038] In another embodiment, the start time of the process window for the first process is a second time obtained by summing a first switching period and a preset safety margin from the first time. The preset safety margin has a range of ±50ms, and the specific value is adjusted according to the process accuracy requirements.

[0039] This embodiment increases the safety margin to compensate for minor system fluctuations and process drift, preventing the process from starting before the pressure is fully stable, ensuring process uniformity and consistency, and is suitable for scenarios with extremely high process accuracy requirements.

[0040] Furthermore, the termination time of the process window for the first process is the third time when the first flow gas is switched to the second flow gas.

[0041] Using the flow switching command as the window termination time eliminates the need for additional pressure reduction assessment, maximizing the utilization of the entire time after pressure stabilization and avoiding efficiency losses due to premature process termination or yield reductions due to delayed process termination.

[0042] Furthermore, the method also includes: recording the second switching period when the measured pressure changes from the first pressure to the second pressure; the start time of the process window for the second process is the fifth time obtained after the second switching period, starting from the fourth time when the first flow gas changes to the second flow gas. The end time of the process window for the second process is the sixth time when the second flow gas changes back to the first flow gas.

[0043] This embodiment enables bidirectional pressure switching process window determination, covering both process stages of the complete cycle process, ensuring that the process window of the entire cycle is fully utilized, and further improving overall production efficiency.

[0044] Please see Figure 2 , Figure 2 This is a schematic diagram illustrating the timing relationship between pressure, flow rate, and process window in an embodiment of the present invention. The upper curve is the measured pressure curve output by pressure gauge 400, the middle curve is the inlet flow rate switching curve, and the lower rectangle represents the process window. As can be seen from the figure, after the first flow rate switching, the start time of the first process window is determined after the first switching period Δt, and it terminates at the third flow rate switching, without waiting for the pressure gauge reading to fully stabilize.

[0045] The semiconductor processing method provided in this embodiment of the invention includes a pre-calibration stage and a process stage. In the pre-calibration stage, any of the above-mentioned process window determination methods are executed to obtain the start time of the process window. In the process stage, an air intake device and an exhaust device are configured to operate in a preset mode, and the processing process begins at the start time.

[0046] By distinguishing between pre-calibration and process stages, parameters can be calibrated once and reused in multiple batches, avoiding pressure measurement and calculation in each cycle, greatly simplifying the control logic of the process, reducing the system's computational load, and improving response speed.

[0047] The pre-calibration phase is performed after the initial equipment commissioning, process parameter changes, or equipment maintenance. The specific steps are as follows: Configure the target process conditions, including the first flow rate gas, the second flow rate gas, the type of process gas, and the control mode of the exhaust device; The process window determination method is implemented, and the first switching period when the measured pressure changes from the second pressure to the first pressure is recorded. The start time of the process window of the first process is determined based on the first time when the second flow gas changes to the first flow gas and the first switching period. A pre-calibration stage is performed in advance to establish a database of switching time periods corresponding to different process conditions. The process conditions include at least one of the following: first flow gas, second flow gas, exhaust device control mode, and process gas type.

[0048] By establishing a database of switching time periods, it is possible to quickly switch between different process formulas without having to recalibrate every time the process is changed, thereby improving production flexibility and changeover efficiency.

[0049] The exhaust device control modes include: maintaining the target opening degree unchanged during the pre-calibration stage and the process stage, and / or adjusting the fluctuation by a preset amplitude based on the target opening degree during the pre-calibration stage and the process stage.

[0050] The fixed opening mode improves system robustness, ensuring that the stable pressure within the chamber is primarily controlled by the intake. Based on preset fluctuations around the target opening, the fluctuation amplitude and period can be preset, with the fluctuation period matching the intake switching cycle. This accelerates the chamber pressure response speed, shortens the pressure switching transition time, and further increases throughput. The target opening can be pre-calibrated or obtained through machine learning based on previous process cycles.

[0051] The specific steps of the process stage are as follows: During the process, the corresponding first switching period is retrieved from the switching period database according to the current process conditions; The intake device 200 and the exhaust device 300 are configured to operate in a preset mode; The processing begins at the start time.

[0052] The process stage adopts open-loop control, which eliminates the need to read pressure gauge data in real time, completely eliminating the impact of pressure gauge failure on the process and improving the stability and reliability of system operation.

[0053] In one optional embodiment, a pre-calibration phase can be performed periodically to update the switching time period database, in order to compensate for characteristic drift caused by factors such as equipment aging and connection channel contamination, and to ensure the long-term accuracy of process window determination.

[0054] Please see Figure 3 This invention provides a semiconductor processing apparatus, comprising: The process cavity 100 contains a base 101 for supporting the substrate W; An air intake device 200 is connected to the process chamber 100 and is used to control the type and flow rate of the process gas supplied to the process chamber 100. The exhaust device 300 is connected to the process chamber 100 and is used to evacuate the process chamber 100. Pressure gauge 400 is connected to process chamber 100 to measure the pressure inside process chamber 100 and output the measured pressure. The controller 600 is communicatively connected to the intake device 200, the exhaust device 300 and the pressure gauge 400, respectively, and the controller 600 is configured to execute any of the above-mentioned semiconductor processing methods.

[0055] By integrating the aforementioned process window determination method, this equipment enables automatic and accurate determination of process windows without manual intervention, thereby improving the automation level and production efficiency of the equipment.

[0056] Furthermore, the device also includes an RF component 800 for exciting plasma within the process chamber 100 to process the substrate W. A controller 600 is communicatively connected to the RF component 800 and is configured to turn on the RF component 800 at the start time of the process window and turn off the RF component 800 at the end time of the process window.

[0057] By precisely controlling the switching timing of RF components, the plasma is ensured to operate only within a stable pressure process window, avoiding the impact of pressure fluctuations on plasma characteristics and improving process uniformity and product yield.

[0058] For example, the base 101 may integrate heating, electrostatic adsorption and cooling functions; the air intake device 200 includes a first air intake valve 201, a second air intake valve 202 and a mass flow controller 203; the exhaust device 300 includes a vacuum valve 301 and a vacuum pump 302; the radio frequency component 800 includes a radio frequency power supply, a matching network and upper and lower electrodes.

[0059] The semiconductor processing equipment of this invention can be used as an atomic layer etching equipment, an atomic layer deposition equipment, or a plasma etching equipment, and is particularly suitable for cyclic process scenarios that require high-speed pressure switching.

[0060] This invention records the first switching period when the measured pressure changes from a second pressure to a first pressure. Based on the first time the second flow rate gas switches to the first flow rate gas and the first switching period, the start time of the process window for the first process is determined. This allows the process to start without waiting for the pressure gauge reading to fully stabilize, effectively increasing the process window time and improving equipment capacity. By distinguishing between the pre-calibration stage and the process stage, the process window determination method is executed during the pre-calibration stage to obtain the start time of the process window. During the process stage, the intake and exhaust devices are configured to operate in a preset mode and begin processing at the start time, simplifying the process control logic and improving production efficiency. Simultaneously, a semiconductor processing device capable of executing the above-mentioned semiconductor processing method is provided, achieving accurate determination and efficient control of the process window.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining a process window, characterized in that, include: A process chamber is provided, the process chamber is connected to an air inlet device, an exhaust device and a pressure gauge, the air inlet device controls the flow rate of the process gas supplied into the process chamber, the exhaust device is used to evacuate the process chamber, and the pressure gauge is used to measure the pressure inside the process chamber and output the measured pressure. The intake and exhaust devices are configured to operate in a preset mode, which includes alternately supplying a first flow rate gas and a second flow rate gas, so that the measured pressure is maintained at a first pressure under the first flow rate gas to perform a first process, and maintained at a second pressure under the second flow rate gas to perform a second process. Record the first switching time period when the measured pressure switches from the second pressure to the first pressure; The start time of the process window for the first process is determined based on the first time when the second flow gas is switched to the first flow gas and the first switching period.

2. The process window determination method as described in claim 1, characterized in that, The start time of the process window for the first process is: the second time obtained after the first switching period, starting from the first time when the second flow gas is switched to the first flow gas.

3. The process window determination method as described in claim 1, characterized in that, The process window termination time for the first process is the third time when the first flow gas is switched to the second flow gas.

4. The process window determination method as described in claim 1, characterized in that, Also includes: Record the second switching time period when the measured pressure changes from the first pressure to the second pressure; The start time of the process window for the second process is the fifth time obtained after the second switching period, starting from the fourth time when the first flow gas is switched to the second flow gas.

5. The process window determination method as described in claim 4, characterized in that, The process window termination time for the second process is the sixth time after the second flow gas is switched to the first flow gas.

6. The process window determination method as described in claim 1, characterized in that, The start time of the process window for the first process is: the second time obtained by summing the first switching period and a preset safety margin from the first time.

7. A semiconductor processing method, characterized in that, include: The pre-calibration stage and the process stage, wherein the pre-calibration stage executes the process window determination method as described in any one of claims 1-6 to obtain the start time of the process window; The process stage configures the air intake device and exhaust device to operate in the preset mode, and the processing begins at the start time.

8. The semiconductor processing method as described in claim 7, characterized in that, The pre-calibration stage is performed in advance to establish a database of switching time periods corresponding to different process conditions. The process conditions include at least one of the following: first flow gas, second flow gas, exhaust device control mode, and process gas type. During the process, the corresponding first switching time period is retrieved from the switching time period database according to the current process conditions.

9. The semiconductor processing method as described in claim 8, characterized in that, The exhaust device control modes include: Maintain the target opening degree unchanged during the pre-calibration and process stages, and / or During the pre-calibration and process stages, the fluctuation range is adjusted based on the target opening degree with a preset amplitude.

10. A semiconductor processing apparatus, characterized in that, include, The process cavity contains a base for supporting the substrate; An air intake device, connected to the process chamber, is used to control the type and flow rate of the process gas supplied to the process chamber; An exhaust device, connected to the process chamber, is used to evacuate the process chamber; A pressure gauge, connected to the process chamber, is used to measure the pressure inside the process chamber and output the measured pressure; A controller is communicatively connected to the intake device, the exhaust device, and the pressure gauge, respectively, and the controller is configured to perform the semiconductor processing method as described in any one of claims 7 to 9.

11. The semiconductor processing apparatus as claimed in claim 10, characterized in that, It also includes a radio frequency (RF) component for exciting plasma within the process cavity to process the substrate, and a controller communicatively connected to the RF component, the controller being configured to turn on the RF component at the start time of the process window and turn off the RF component at the end time of the process window.

Images