Chamber pressure measurement system, semiconductor processing apparatus, and processing method

Abstract

The application discloses a chamber pressure measurement system, a semiconductor processing device and a processing method. The chamber pressure measurement system comprises a chamber, a pressure gauge, a connecting channel, a flow meter and a controller. The pressure in the chamber can be switched between a pressure change period and a pressure stable period; the pressure gauge is arranged outside the chamber and is communicated with the chamber through the connecting channel; the flow meter is arranged on the connecting channel and is used for detecting the gas flow in the connecting channel; the controller is in communication connection with the pressure gauge and the flow meter; when the flow meter detects that the gas flow in the connecting channel is less than a first threshold value, it is determined that the pressure in the chamber is in the pressure stable period. The gas flow in the connecting channel is detected by the flow meter to determine the pressure stable state in the chamber, which can effectively solve the lag problem caused by the dependence on the pressure gauge reading to determine the pressure stability in the prior art, and is particularly suitable for semiconductor processes requiring rapid pressure switching, and can significantly improve the process efficiency and process consistency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing technology, and more specifically to a chamber pressure measurement system, a semiconductor processing device, and a processing method. Background Technology

[0002] In various industrial processes requiring precise pressure control, the pressure within the chamber is one of the key parameters affecting process quality. Especially in semiconductor manufacturing processes, such as atomic layer etching (ALE) and atomic layer deposition (ALD), the pressure within the chamber needs to be rapidly switched between different target values, and the process can only begin after the pressure has stabilized to ensure consistency and repeatability.

[0003] In existing technologies, pressure gauges (also known as vacuum gauges) are typically used to measure the pressure within a chamber, as seen in Chinese patent applications CN121122993A, CN121096914A, CN121790264A, and CN121768935A. 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 due to limitations imposed by the chamber wall thickness and the pressure gauge's installation and connection requirements; this volume is 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 is on the same order of magnitude as the pressure gauge response time, this lag becomes unacceptable. For example, in the ALE process, the pressure inside the chamber needs to be switched rapidly between high and low pressure repeatedly, and after each switch, the pressure needs to stabilize before the process can begin. If the pressure stabilization 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, such as atomic layer etching (ALE), the loss of tens of milliseconds of process window time per cycle will significantly reduce the equipment's throughput.

[0005] Therefore, there is an urgent need for a system and method that can accurately and quickly determine the stable state of pressure within a 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 lag problem caused by relying on the stability of pressure gauge readings to determine pressure stability in the prior art, and to provide a chamber pressure measurement system, semiconductor processing device and method that can quickly and accurately determine the pressure stability state in the chamber, effectively improving process efficiency and process consistency.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A chamber pressure measurement system is provided, comprising: A chamber, wherein the pressure within the chamber switches between a pressure change period and a pressure stability period, and the rate of pressure change within the chamber during the pressure stability period is less than the rate of pressure change within the chamber during the pressure change period; A pressure gauge, located outside the chamber, is used to measure the pressure inside the chamber; A connecting channel connects the chamber to the pressure gauge; A flow meter, installed in the connection channel, is used to detect the gas flow rate within the connection channel; A controller, communicatively connected to the pressure gauge and the flow meter, is configured to: When the flow meter detects that the gas flow rate in the connection channel is less than a first threshold, it determines that the pressure in the chamber is in the pressure stabilization period.

[0008] In some embodiments, the controller is configured to: when the flow meter detects that the gas flow rate in the connection channel is greater than a second threshold, determine that the pressure in the chamber is in the pressure change period, wherein the second threshold is not less than the first threshold.

[0009] In some embodiments, the system further includes a shut-off valve disposed on the connection channel for closing the connection channel during non-pressure measurement periods to isolate and protect the pressure gauge.

[0010] In some embodiments, the flow meter includes a surface-mount flow meter attached to the inner and / or outer wall of the connection channel.

[0011] In some embodiments, the pressure gauge includes a capacitive diaphragm pressure gauge.

[0012] In some embodiments, the flow meter is located on the side of the connection channel closer to the chamber relative to the pressure gauge.

[0013] In some embodiments, the controller is further configured to measure the stable pressure of the chamber during the pressure stabilization period using the pressure gauge, and compare the stable pressure with a target pressure to verify whether the pressure inside the chamber has reached the target pressure.

[0014] In some embodiments, a temperature control device is provided on the connection channel, which is used to control the temperature of the section between the flow meter and the pressure gauge on the connection channel to reduce the temperature difference in that section.

[0015] In some embodiments, the flow meter and the connection channel are thermally isolated.

[0016] A semiconductor processing apparatus is provided, including the aforementioned chamber pressure measurement system. The chamber contains a substrate and has an air inlet and an air outlet. The controller is communicatively connected to both the intake and exhaust sections, and is configured to: The system controls the intake section to supply process gas to the chamber and controls the exhaust section to evacuate the chamber, causing the pressure inside the chamber to switch between a pressure change period and a pressure stabilization period. The substrate is then processed during the pressure stabilization period. At a first moment, the flow meter detects that the gas flow rate in the connection channel begins to be less than a first threshold, and takes the first moment as the start time of the process window.

[0017] In some embodiments, the controller is configured to: at a second time after the first time, the flow meter detects that the gas flow rate in the connection channel begins to exceed a second threshold, and uses the second time as the termination time of the process window, wherein the second threshold is not less than the first threshold.

[0018] In some embodiments, a plasma source is further included, and the controller is communicatively connected to the plasma source, the controller being configured to control the plasma source to excite plasma in the chamber within the process window to process the substrate.

[0019] A semiconductor processing method is provided, comprising: A chamber is provided, wherein a substrate is carried inside the chamber, and the chamber is connected to a pressure gauge outside the chamber via a connecting channel to measure the pressure inside the chamber. The connecting channel is provided with a flow meter for detecting the gas flow rate therein. Process gas is supplied to the chamber while a vacuum is simultaneously drawn to perform pressure regulation. At a first moment, the flow meter detects that the gas flow rate in the connection channel begins to be less than a first threshold, and takes the first moment as the start time of the process window to carry out the processing.

[0020] In some embodiments, at a second time after the first time, the flow meter detects that the gas flow rate in the connection channel begins to exceed a second threshold, and the second time is taken as the end time of the process window, wherein the second threshold is not less than the first threshold.

[0021] In some embodiments, at a third time point, the pressure gauge reading tends to stabilize, and the pressure reading of the pressure gauge is obtained. The third time point is between the first time point and the second time point. The inlet flow rate of the process gas is adjusted based on the difference between the reading pressure and the target pressure to stabilize the pressure inside the chamber at the target pressure.

[0022] In some embodiments, a reference threshold is set such that the first threshold is equal to the reference threshold minus a fixed offset, and the second threshold is equal to the reference threshold plus the fixed offset, wherein the fixed offset is pre-calibrated based on the response characteristics of the flow meter; At the first moment, process gas of a first flow rate is continuously supplied to the chamber to stabilize the pressure inside the chamber at a first pressure; At the second time, the supply of the process gas is stopped, causing the pressure in the chamber to begin to change; At the third time, the flow meter detects that the gas flow rate in the connection channel begins to exceed the second threshold; Based on the time difference between the third time and the second time, the reference threshold is calibrated so that the time difference approaches zero.

[0023] The beneficial effects of this invention are as follows: This invention utilizes a flow meter installed on the connection channel of a pressure gauge to determine the pressure stability within a chamber by observing changes in gas flow rate within the connection channel. When the pressure within the chamber changes, gas flow occurs within the connection channel, which the flow meter detects. When the pressure within the chamber reaches a stable state, the gas flow in the connection channel stops or becomes very weak, and the gas flow rate detected by the flow meter is less than a first threshold. The flow meter can be positioned closer to the chamber than the pressure gauge, enabling it to detect the pressure stability state earlier than the pressure gauge.

[0024] This invention uses the point when the flow meter detects that the gas flow rate is less than a first threshold as the starting point of the pressure stabilization period, effectively solving the lag problem caused by relying on stable pressure gauge readings to determine pressure stability in existing technologies. In processes requiring rapid pressure switching, it can significantly shorten waiting time and improve process efficiency. Furthermore, because the pressure stability determination is more accurate, it ensures that each process is performed under the same pressure conditions, thereby improving process consistency and repeatability. Attached Figure Description

[0025] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0026] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0027] Figure 1 This is a schematic diagram of the overall structure of a chamber pressure measurement system according to the present invention; Figure 2 A schematic diagram of the structure of a flow meter; Figure 3 A schematic diagram of the structure for another type of flow meter; Figure 4 A schematic diagram of the structure for yet another type of flow meter; Figure 5 This is a schematic diagram of a patch-type flow meter. Figure 6 This is a schematic diagram of the structure of a semiconductor processing device according to the present invention; Figure 7 This is a comparison curve showing the changes in pressure and flow rate over time according to the present invention.

[0028] Explanation of markings in the diagram: W-substrate; 10-Cavity; 11-Cavity wall; 20-Base; 30 - Exhaust section; 31 - Exhaust port; 32 - Vacuum valve; 33 - Vacuum pump; 40 - Air intake section; 41 - Air source; 421 - First air intake end; 422 - Second air intake end; 431 - First air control section; 432 - Second air control section; 50 - Plasma source; 60-Controller; 100 - Pressure measuring section; 110 - Pressure gauge; 120 - Connection channel; 130 - Flow meter; 131 - First temperature measuring point; 132 - Second temperature measuring point; 133 - Heat source; 134 - Substrate; 140 - Shut-off valve; 150 - Temperature control device; 160 - Thermal isolation structure. Detailed Implementation

[0029] 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.

[0030] Therefore, such as Figure 1 As shown, the chamber pressure measurement system includes a chamber 10, a pressure measuring unit 100, and a controller 60. The pressure measuring unit 100 includes a pressure gauge 110, a connecting channel 120, and a flow meter 130. The pressure inside the chamber 10 can switch between a pressure change period and a pressure stability period. The pressure gauge 110 is located outside the chamber 10 and is connected to the chamber 10 through the connecting channel 120. The flow meter 130 is located on the connecting channel 120. The controller 60 is communicatively connected to the pressure gauge 110 and the flow meter 130. When the flow meter 130 detects that the gas flow rate in the connecting channel 120 is less than a first threshold, the controller 60 determines that the pressure inside the chamber 10 is in a pressure stability period.

[0031] This embodiment utilizes the physical correspondence between pressure balance and flow approaching zero. When a pressure difference exists between chamber 10 and pressure gauge 110, gas flow will inevitably occur within the connecting channel 120. When the pressure reaches equilibrium, the gas flow naturally stops. The response speed of this physical process is determined solely by the velocity of the gas molecules, which is much faster than the response speed of pressure gauge 110. In process scenarios requiring frequent pressure switching, the time saved per pressure switch accumulates with the number of cycles, significantly improving overall process efficiency. Furthermore, earlier stability determination allows the process to proceed during the period of highest pressure stability, improving the consistency of process results. This solves the lag problem caused by prior art relying on pressure gauge reading stability determination, and improves the speed of pressure stability determination.

[0032] The internal space of chamber 10 can be evacuated to a vacuum or filled with gas to create different pressure environments. The internal pressure of chamber 10 can switch between a pressure change period and a pressure stabilization period. During the pressure stabilization period, the rate of pressure change within chamber 10 is less than that during the pressure change period. For example, when the pressure within chamber 10 is in the pressure stabilization period, the rate of pressure change is less than a preset value, such as less than 5% per 100 milliseconds. When the pressure within chamber 10 is in the pressure change period, the pressure within chamber 10 is changing towards the target pressure, and the rate of pressure change is greater than a preset value, such as greater than 10% per 100 milliseconds.

[0033] The pressure gauge 110 is located outside the chamber 10 and is used to measure the pressure inside the chamber 10. The pressure gauge 110 can be various types of pressure measuring devices, such as capacitive diaphragm pressure gauges, Pirani pressure gauges, ionization pressure gauges, etc.

[0034] In one embodiment, the pressure gauge 110 is a capacitive diaphragm pressure gauge. Capacitive diaphragm pressure gauges have advantages such as high accuracy, good stability, and insensitivity to the type of gas.

[0035] A capacitive diaphragm manometer contains a metal diaphragm that deforms when the pressure on either side differs. By measuring the degree of deformation, the pressure difference can be calculated. Capacitive diaphragm manometers typically have a reference chamber maintained at a known reference pressure. When the measuring chamber is connected to the pressure being measured, the pressure difference causes the diaphragm to deform, thus changing the capacitance between the diaphragm and the fixed electrode. By measuring the change in capacitance, the magnitude of the measured pressure can be calculated.

[0036] The pressure gauge 110 has an internal volume, which is the volume of the internal measuring chamber. The size of the internal volume affects the response speed and accuracy of pressure measurement. Generally speaking, the smaller the internal volume, the faster the response speed, but the measurement accuracy may be reduced.

[0037] The connecting channel 120 is a tubular structure that connects the chamber 10 and the pressure gauge 110, enabling the pressure gauge 110 to measure the pressure inside the chamber 10. It can be understood that the connecting channel 120 needs to penetrate the cavity wall 11 of the chamber 10, and the tubular structure portion in the cavity wall 11 can also be part of the connecting channel 120.

[0038] For example, the connecting channel 120 is typically made of materials such as stainless steel or aluminum alloy, which have good airtightness and corrosion resistance.

[0039] The flow meter 130 is installed on the connection channel 120 and is used to detect the gas flow rate within the connection channel 120. The flow meter 130 can be various types of flow measurement devices, such as thermal mass flow meters, differential pressure flow meters, vortex flow meters, etc.

[0040] In one embodiment, such as Figures 2 to 4 As shown, flow meter 130 is a surface-mount flow meter, attached to the inner and / or outer wall of connection channel 120. Using a MEMS surface-mount thermal mass flow meter offers advantages such as small size, easy installation, fast response, and high accuracy.

[0041] MEMS thermal mass flow meters can be used as follows Figure 5As shown, a heat source 133 and two temperature sensing elements (first temperature sensing point 131 and second temperature sensing point 132) are disposed on the sensor chip, located upstream and downstream of the heat source 133 respectively, and integrated on the substrate 134. When gas flows through the sensor chip, the gas carries away the heat generated by the heat source 133, resulting in a temperature difference between the first temperature sensing point 131 and the second temperature sensing point 132. The magnitude of the temperature difference is proportional to the mass flow rate of the gas. By measuring the magnitude of the temperature difference, the mass flow rate of the gas can be calculated.

[0042] Since the flow meter 130 can be positioned closer to the chamber 10 than the pressure gauge 110, the flow meter 130 is the first to capture changes in the pressure inside the chamber. In particular, the flow meter 130 does not need to have precise readings; it only needs to have a reading within a preset range to determine the time when the pressure stabilizes.

[0043] In one embodiment, the flow meter 130 is located on the side of the connection channel 120 closer to the chamber 10 relative to the pressure gauge 110. This allows the flow meter 130 to detect flow changes between the chamber 10 and the connection channel 120 earlier, improving the timeliness of pressure stability determination.

[0044] The controller 60 is communicatively connected to the pressure gauge 110 and the flow meter 130, respectively, to receive the detection signals from the pressure gauge 110 and the flow meter 130, and to perform control and judgment based on the detection signals. The controller 60 can be various types of control devices such as PLC (Programmable Logic Controller), microcontroller, industrial computer, DSP (Digital Signal Processor).

[0045] The controller 60 is configured to determine that the pressure in chamber 10 is in a stable period when the flow meter 130 detects that the gas flow rate in the connection channel 120 is less than a first threshold. The first threshold is a small value close to zero and can be set according to actual application requirements. For example, the first threshold can be set to 0.5 sccm. When the gas flow rate in the connection channel 120 is less than 0.5 sccm, it is considered that the gas flow has basically stopped and the pressure in chamber 10 has reached a stable state.

[0046] In one embodiment, the controller 60 is further configured to determine that the pressure in the chamber 10 is in a pressure change period when the flow meter 130 detects that the gas flow rate in the connection channel 120 is greater than a second threshold. The second threshold is not less than the first threshold and can also be set according to actual application requirements. In one embodiment, the second threshold is set to 1 sccm. When the gas flow rate in the connection channel 120 is greater than 1 sccm, it is considered that the pressure in the chamber 10 is changing.

[0047] Setting two different thresholds can prevent misjudgments due to flow fluctuations. For example, when the flow fluctuates around the first threshold, setting only one threshold may cause the controller 60 to frequently switch its judgment between periods of stable pressure and periods of pressure change. By setting two different thresholds, a hysteresis loop can be formed, improving the stability of the judgment.

[0048] In one embodiment, the chamber pressure measurement system further includes a shut-off valve 140, disposed on the connection channel 120, located upstream of the pressure gauge 110, such as... Figures 2 to 4 As shown. The shut-off valve 140 is used to close the connection channel 120 during non-pressure measurement times to protect the pressure gauge 110 from damage caused by high-pressure impacts, high temperatures, or corrosive gases. The shut-off valve 140 can be various types of valves, such as pneumatic valves or solenoid valves. For example, the shut-off valve 140 is a pneumatic vacuum diaphragm valve, which has advantages such as good airtightness, fast response speed, and strong corrosion resistance.

[0049] When the pressure inside chamber 10 exceeds the preset safety pressure, the shut-off valve 140 is closed, isolating the pressure gauge 110 from chamber 10. The preset safety pressure is the maximum operating pressure that the pressure gauge 110 can withstand. When the pressure inside chamber 10 drops below the preset safety pressure, the shut-off valve 140 opens, connecting the pressure gauge 110 to chamber 10, and pressure measurement begins.

[0050] In one embodiment, the connecting channel 120 is further provided with a temperature control device 150 to reduce the temperature difference between the flow meter 130 and the pressure gauge 110 in the connecting channel 120, such as... Figure 4 As shown. The temperature control device 150 can be various types of temperature control equipment such as heating belts, cooling water pipes, and Peltier elements.

[0051] In one embodiment, the temperature control device 150 is a flexible heating strip wrapped around the outer wall of the connecting channel 120.

[0052] The function of the temperature control device 150 is to maintain the temperature of the connecting channel 120 within a constant range to reduce the impact of temperature variations on the accuracy of pressure measurement. At low pressures in the mTorr range, the Knudsen effect can easily lead to measurement errors. By controlling the temperature of the connecting channel 120, the temperature difference between the two ends of the connecting channel can be reduced, thereby mitigating the impact of the Knudsen effect on the accuracy of low-pressure measurements.

[0053] In one embodiment, multiple temperature sensors (not shown) are also provided on the connection channel 120 for real-time detection of the temperature of the connection channel 120. The controller 60 is communicatively connected to the temperature sensors and the temperature control device 150, and is used to adjust the power of the temperature control device 150 according to the detection results of the temperature sensors to maintain a constant temperature in the connection channel 120.

[0054] In one embodiment, the flow meter 130 and the connecting channel 120 are thermally isolated, such as by providing a thermal isolation structure 160. Figure 4 As shown. The thermal isolation structure 160 is used to reduce the impact of temperature changes in the connection channel 120 on the measurement accuracy of the flow meter 130. The working principle of the MEMS thermal mass flow meter is based on heat transfer, and changes in ambient temperature will affect its measurement accuracy. By setting the thermal isolation structure 160, the heat exchange between the flow meter 130 and the connection channel 120 can be reduced, thereby improving the accuracy of flow measurement.

[0055] The thermal isolation structure 160 can be made of various materials with low thermal conductivity, such as PEEK (polyetheretherketone), alumina ceramic, polytetrafluoroethylene, etc. In one embodiment, the thermal isolation structure 160 is a thermal isolation ring made of PEEK material. The thermal isolation ring is installed between the flow meter 130 and the connecting channel 120, which can effectively reduce heat transfer.

[0056] The controller 60 is also configured to measure the stable pressure within chamber 10 during the pressure stabilization period using pressure gauge 110, and calibrate whether this stable pressure is the target pressure. Although flow meter 130 can quickly and accurately determine the pressure stabilization state, it cannot directly measure the absolute value of the pressure. Therefore, after determining that the pressure is stable, it is still necessary to measure the specific value of the stable pressure using pressure gauge 110 and compare it with the target pressure to ensure that the pressure within chamber 10 has indeed reached the target pressure required by the process.

[0057] In the process, if the difference exceeds the preset error range, it is necessary to adjust the air intake flow rate or the pumping rate to bring the pressure inside chamber 10 to the target pressure. In one embodiment, the preset error range is ±5%, which can be adjusted to ±1% to ±10% depending on the accuracy requirements of different processes.

[0058] This invention discloses a semiconductor processing apparatus, such as... Figure 6 As shown, the system includes the aforementioned chamber pressure measurement system. A base 20 is disposed within the chamber 10 to support the substrate W. The substrate W is a workpiece that requires semiconductor processing. The base 20 may have functions such as heating, cooling, and electrostatic adsorption to meet the requirements of different processes.

[0059] The chamber 10 has an inlet 40 and an outlet 30. The inlet 40 is connected to a gas source 41 via a gas pipeline and includes a first inlet end 421 and a second inlet end 422, corresponding to a first gas control unit 431 and a second gas control unit 432, respectively, for supplying different process gases into the chamber 10. The gas control unit is used to precisely control the gas flow rate and may include a mass flow controller (MFC) or an upstream pressure controller (UPC). The outlet 30 is connected to a vacuum pipeline via an outlet 31. The vacuum pipeline is sequentially connected to a vacuum valve 32 and a vacuum pump 33 for evacuating the chamber 10. The vacuum valve 32 is used to control the pumping rate.

[0060] The controller 60 is communicatively connected to the first gas control unit 431, the second gas control unit 432, and the vacuum valve 32, respectively, and is used to control the inlet flow rate and pumping rate of the process gas, thereby regulating the pressure inside the chamber 10. The controller 60 is configured to: control the inlet unit 40 to supply process gas to the chamber 10, and control the exhaust unit 30 to evacuate the chamber 10, so that the pressure inside the chamber 10 switches between a pressure change period and a pressure stabilization period, and process the substrate W during the pressure stabilization period.

[0061] At the first moment, when the flow meter 130 detects that the gas flow rate in the connection channel 120 begins to fall below a first threshold, the controller 60 uses this first moment as the start time of the process window. The process window refers to a period of time suitable for semiconductor process handling, during which the pressure in the chamber 10 remains stable.

[0062] In one embodiment, the controller 60 is further configured to: at a second time after the first time, when the flow meter 130 detects that the gas flow rate in the connection channel 120 begins to exceed a second threshold, use the second time as the end time of the process window.

[0063] In one embodiment, the semiconductor processing apparatus further includes a plasma source 50, and a controller 60 is communicatively connected to the plasma source 50. The plasma source 50 is used to generate plasma within the chamber 10 to perform etching or deposition processes on the substrate W. The plasma source 50 can be various types of plasma sources, such as an inductively coupled plasma (ICP) source, a capacitively coupled plasma (CCP) source, or a transformer-coupled plasma (TCP) source.

[0064] The controller 60 is configured to control the plasma source 50 to generate plasma within the chamber 10 within a process window to process the substrate W. This ensures that the plasma processing is carried out under stable pressure conditions, thereby improving process quality and consistency.

[0065] The semiconductor processing method disclosed in this invention includes the following steps: A chamber 10 is provided, in which a substrate W is carried. The chamber 10 is connected to a pressure gauge 110 outside the chamber via a connecting channel 120 to measure the pressure inside the chamber 10. A flow meter 130 is provided in the connecting channel 120 to detect the gas flow rate within the connecting channel 120. Process gas is supplied to the chamber 10 while a vacuum is simultaneously drawn for pressure regulation. At a first moment, the flow meter 130 detects that the gas flow rate in the connecting channel 120 begins to fall below a first threshold, and this first moment is taken as the start time of the process window for processing. By determining the start time of the process window based on the flow rate of the flow meter 130, the ineffective waiting time in the process cycle is reduced, and the production capacity is improved.

[0066] In one embodiment, at a second time after the first time, the flow meter 130 detects that the gas flow rate in the connection channel 120 begins to exceed a second threshold, and the second time is taken as the end time of the process window, wherein the second threshold is not less than the first threshold.

[0067] In one embodiment, at a third moment, the pressure gauge 110 reading tends to stabilize, and the reading pressure is recorded. This third moment falls between the first and second moments. Based on the difference between the reading pressure and the target pressure, the process gas inlet flow rate is adjusted to stabilize the pressure within chamber 10 at the target pressure. In actual processes, the pressure within the chamber can drift slowly due to various factors, such as adsorption and desorption of the process gas by the chamber 10 wall, changes in substrate W temperature, fluctuations in the vacuum pump 33 pumping speed, changes in gas source 41 pressure, and slight drifts in valve opening. These factors can cause the pressure within the chamber to gradually deviate from the target pressure within the process window, affecting the repeatability of the process results. In this embodiment, within the process window, once the pressure gauge 110 reading stabilizes, the process gas inlet flow rate is dynamically adjusted based on the difference between the measured value of pressure gauge 110 and the target pressure to compensate for pressure drift, ensuring that the pressure within chamber 10 remains stable near the target pressure. This dynamic adjustment method effectively suppresses pressure fluctuations caused by various interference factors, improves the pressure stability of the process, thereby improving the repeatability and consistency of process results and reducing batch-to-batch variations.

[0068] The following is combined with Figure 7 This invention provides a detailed explanation of the process for determining pressure stability.

[0069] Figure 7 This is a comparison graph showing the pressure and flow rate changes over time according to the present invention, where the horizontal axis represents time, and the vertical axes represent pressure and flow rate, respectively. The upper curve is the pressure change curve measured by pressure gauge 110, and the lower curve is the flow rate change curve detected by flow meter 130.

[0070] As can be seen, the flow signal exhibits a trend of first amplifying and then approaching zero during the switching process between the first pressure P1 and the second pressure P2, and remains near zero for most of the time while the pressure is stable at P1 or P2. Notably, the flow signal approaches zero earlier than the pressure signal, as indicated by ΔT1 and ΔT2 in the figure. This allows for earlier detection of changes in the pressure state within the cavity, particularly in determining when the pressure enters the stable pressure period. Compared to traditional methods that rely on stable pressure gauge readings, this allows for earlier opening of the process window and commencement of the process, controlling the process window opening time, improving process efficiency, and avoiding mismatches between the actual pressure within the cavity and the pressure gauge readings, which could cause the process to operate within a non-ideal pressure range. Therefore, this embodiment helps improve process yield.

[0071] Furthermore, this invention can also be used to determine the termination time of a process window. When the pressure inside chamber 10 begins to change, the flow meter 130 can immediately detect the increase in flow rate, thereby determining the end of the process window. Accurately determining the termination time of the process window facilitates timely termination of the process, avoids operating the process in an unstable pressure environment, and helps improve yield.

[0072] Of course, the termination time can correspond to the initial time of the gas inlet switching or vacuum valve opening switching action. In some processes, such as the ALE process, the process gas pressure corresponds to the process gas, and the process gas pressure is different in different process stages. The switching of the cavity pressure is synchronized with the switching of the process gas. For example, the first pressure P1 corresponds to the first gas, and the second pressure P2 corresponds to the second gas. When the pressure switches from P1 to P2, the first gas stops supplying, and the second gas starts supplying during the switching. Therefore, the end period of the process window can be directly determined by the time point when the first gas stops supplying. However, since the start time of the process window cannot be preset, it can only start after the pressure stabilizes. Therefore, it is necessary to rely on the determination of the start time of the process window based on the flow rate of flow meter 130. Thus, this embodiment establishes a calibration mechanism based on the time delay relationship between the time point of the gas switching action and the readings of flow meter 130 and pressure gauge. That is, in the process, the first gas and the second gas are alternately supplied into the chamber 10. The target process pressure of the first gas is the first pressure P1, and the target process pressure of the second gas is the second pressure P2. The first pressure P1 and the second pressure P2 are mainly controlled by the flow rates of the first gas and the second gas. When the gas in the chamber switches from the first gas to the second gas, the pressure in the chamber also changes synchronously. The starting point of the gas change is used as the calibration time point for the delayed response of the flow meter 130 or the pressure gauge 110.

[0073] For example, at the first time, the first gas is continuously supplied, and the pressure inside the cavity stabilizes at the first pressure P1, indicating a pressure stabilization period. The flow meter 130 reading approaches zero, and the pressure gauge 110 reading stabilizes at the first pressure P1. At the second time, the first gas supply stops, and preparation begins for the supply of the second gas. At this time, the pressure inside the cavity should begin to switch from the first pressure P1 to the second pressure P2, indicating a pressure change period. Therefore, the second time is the calibration point for the pressure gauge and flow meter. At the third time, the flow meter 130 reading is greater than the second threshold. The first time difference between the third and second times is recorded, and the flow meter 130 is used to determine that the cavity is in a pressure change period. At the fourth time, the pressure gauge 110 reading begins to change towards the second pressure P2, and the second time difference between the fourth and second times is recorded. At the fifth time, the second gas supply continues, and the flow meter 130 reading is less than the first threshold. It is presumed that the pressure inside the cavity stabilizes at the second pressure P2, indicating a pressure stabilization period. Therefore, the processing based on the second pressure P2 is initiated. At this time, the first threshold and / or the second threshold can be corrected using the first time difference.

[0074] For example, a reference threshold Th0 and a fixed offset ΔTh are pre-set, establishing a linkage between the first threshold Th1, the second threshold Th2, and the reference threshold Th0. Specifically, the first threshold equals the reference threshold minus the fixed offset, and the second threshold equals the reference threshold plus the fixed offset. The first threshold is used to determine when the chamber pressure enters a stable period, serving as the initial trigger condition for the process window. The second threshold is used to determine when the chamber pressure enters a changing period, serving as the termination trigger condition for the process window. The reference threshold is the core calibration parameter, dynamically adjusted based on the rise time difference during the process. The fixed offset is a pre-calibrated constant used to compensate for the asymmetry in the flowmeter's rise and fall response, while simultaneously forming an anti-interference hysteresis loop with a width twice the fixed offset. The fixed offset ΔTh can be calibrated once before the equipment leaves the factory, requiring no on-site adjustment.

[0075] However, considering the potential inconsistencies in deviations under different processes, gases, and pressures, and the difficulty in directly establishing recursive correlations, this calibration can be used to improve the accuracy of process window determination based on flowmeter 130, rather than being the sole standard. By dynamically calibrating the reference threshold, the influence of individual flowmeter differences, gas types, and temperature variations on determination accuracy can be eliminated, further improving the accuracy and robustness of process window determination.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. For example, the flow meter in the present invention can be other types of flow meters, as long as its response speed is fast enough; the temperature control device can be other types of temperature control equipment, as long as it can accurately control the temperature of the connected channel; the controller can be other types of control equipment, as long as it can implement the control logic of the present invention.

Claims

1. A chamber pressure measurement system, comprising: A chamber, wherein the pressure within the chamber switches between a pressure change period and a pressure stability period, and the rate of pressure change within the chamber during the pressure stability period is less than the rate of pressure change within the chamber during the pressure change period; A pressure gauge, located outside the chamber, is used to measure the pressure inside the chamber; A connecting channel connects the chamber to the pressure gauge; characterized in that it further includes: A flow meter, installed in the connection channel, is used to detect the gas flow rate within the connection channel; A controller, communicatively connected to the pressure gauge and the flow meter, is configured to: When the flow meter detects that the gas flow rate in the connection channel is less than a first threshold, it determines that the pressure in the chamber is in the pressure stabilization period.

2. The chamber pressure measurement system as described in claim 1, characterized in that, The controller is configured to determine that when the flow meter detects that the gas flow rate in the connection channel is greater than a second threshold, the pressure in the chamber is in the pressure change period, and the second threshold is not less than the first threshold.

3. The chamber pressure measurement system as described in claim 1, characterized in that, Also includes: A shut-off valve, installed on the connection channel, is used to close the connection channel during non-pressure measurement periods to isolate and protect the pressure gauge.

4. The chamber pressure measurement system as described in claim 1, characterized in that, The flow meter includes a surface-mount flow meter, which is attached to the inner wall and / or outer wall of the connection channel.

5. The chamber pressure measurement system as described in claim 1, characterized in that, The pressure gauge includes a capacitive diaphragm pressure gauge.

6. The chamber pressure measurement system as described in claim 1, characterized in that, The flow meter is located on the side of the connection channel closer to the chamber, relative to the pressure gauge.

7. The chamber pressure measurement system as described in claim 1, characterized in that, The controller is also configured to measure the stable pressure of the chamber during the pressure stabilization period using the pressure gauge, and compare the stable pressure with a target pressure to verify whether the pressure inside the chamber has reached the target pressure.

8. The chamber pressure measurement system as described in claim 1, characterized in that, The connection channel is equipped with a temperature control device, which is used to control the temperature of the section between the flow meter and the pressure gauge in the connection channel, so as to reduce the temperature difference in this section.

9. The chamber pressure measurement system as described in claim 1, characterized in that, The flow meter and the connecting channel are thermally insulated.

10. A semiconductor processing apparatus, characterized in that, Including the chamber pressure measurement system as described in any one of claims 1 to 9, The chamber is equipped with a base for supporting the substrate, and the chamber has an air inlet and an air outlet. The controller is communicatively connected to both the intake and exhaust sections, and is configured to: The system controls the intake section to supply process gas to the chamber and controls the exhaust section to evacuate the chamber, causing the pressure inside the chamber to switch between a pressure change period and a pressure stabilization period. The substrate is then processed during the pressure stabilization period. At a first moment, the flow meter detects that the gas flow rate in the connection channel begins to be less than a first threshold, and takes the first moment as the start time of the process window.

11. The semiconductor processing apparatus as claimed in claim 10, characterized in that, The controller is configured such that: at a second time after the first time, the flow meter detects that the gas flow rate in the connection channel begins to exceed a second threshold, and the second time is taken as the termination time of the process window, wherein the second threshold is not less than the first threshold.

12. The semiconductor processing apparatus as claimed in claim 10, characterized in that, It also includes a plasma source, and the controller is communicatively connected to the plasma source. The controller is configured to control the plasma source to excite plasma in the chamber within the process window to process the substrate.

13. A semiconductor processing method, characterized in that, include: A chamber is provided, wherein a substrate is carried inside the chamber, and the chamber is connected to a pressure gauge outside the chamber via a connecting channel to measure the pressure inside the chamber. The connecting channel is provided with a flow meter for detecting the gas flow rate therein. Process gas is supplied to the chamber while a vacuum is simultaneously drawn to perform pressure regulation. At a first moment, the flow meter detects that the gas flow rate in the connection channel begins to be less than a first threshold, and takes the first moment as the start time of the process window to carry out the processing.

14. The semiconductor processing method as described in claim 13, characterized in that, At a second time after the first time, the flow meter detects that the gas flow rate in the connection channel begins to exceed a second threshold, and the second time is taken as the end time of the process window, wherein the second threshold is not less than the first threshold.

15. The semiconductor processing method as described in claim 14, characterized in that, At the third moment, the pressure gauge reading tends to stabilize, and the pressure reading of the pressure gauge is obtained. The third moment is between the first moment and the second moment. The inlet flow rate of the process gas is adjusted based on the difference between the reading pressure and the target pressure to stabilize the pressure inside the chamber at the target pressure.

16. The semiconductor processing method as described in claim 14, characterized in that, A reference threshold is set such that the first threshold is equal to the reference threshold minus a fixed offset, and the second threshold is equal to the reference threshold plus the fixed offset, wherein the fixed offset is pre-calibrated based on the response characteristics of the flow meter; At the first moment, process gas of a first flow rate is continuously supplied to the chamber to stabilize the pressure inside the chamber at a first pressure; At the second time, the supply of the process gas is stopped, causing the pressure in the chamber to begin to change; At the third time, the flow meter detects that the gas flow rate in the connection channel begins to exceed the second threshold; Based on the time difference between the third time and the second time, the reference threshold is calibrated so that the time difference approaches zero.

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