Plasma etching equipment and its gas supply components and methods

Abstract

This invention provides a plasma etching apparatus and its gas supply assembly and method. The gas supply assembly includes: a gas control box containing multiple reactive gases for configuring a first process gas and a second process gas; a first gas buffer for temporarily storing the first process gas; a second gas buffer for temporarily storing the second process gas; a gas switching device with its input end connected to the gas control box, its first output end connected to the first gas buffer, and its second output end connected to the second gas buffer; and a gas delivery device connected to the first and second gas buffers for controlling the flow rates of the first and second process gases and diverting them into multiple paths with different flow rates to the reaction chamber. This invention does not limit the number of gas components and can shorten the gas path to achieve rapid gas exchange.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment technology, and in particular to a plasma etching apparatus and its gas supply components and method. Prior Technology

[0002] The principle of wafer etching is to expose the gas introduced into the reaction chamber to an electromagnetic field region to form ionized gas. The ionized gas atoms are accelerated by the electric field, bombard the workpiece surface, and react. The volatile byproducts of the reaction are removed by a vacuum pump. With the development of integrated circuits, the requirements for etching technology are becoming increasingly stringent, and the precision of etching is becoming more and more demanding. Atomic Layer Etching (ALE) technology has also developed rapidly. The ALE process involves rapidly introducing a process gas, which reacts with one or more layers of atoms on the wafer surface. Then, another process gas is rapidly introduced to bombard the modified or treated one or more layers of atoms on the wafer surface, thus etching layer by layer.

[0003] To ensure effective etching, the ALE process requires rapid switching between two process gases, A and B. Therefore, the gases in the gas pipes need to be able to switch quickly and cleanly. In existing machine designs, the gas control box used for mixing and distributing process gases is too far from the reaction chamber, with the gas pipe length between them exceeding 2 meters. One existing machine improvement design involves modifying a sub-gas box within the near-end electrical box near the reaction chamber, and installing several MFCs (Mass Flow Controllers) to control the flow of the corresponding gases. This solution can reduce the length of the gas inlet pipe to about 1 meter. However, due to space limitations, this solution cannot achieve rapid switching between multiple gases. If process gases A and B each have many components, the number of MFCs required for the sub-gas box will increase. This increases the size, making installation and use difficult; furthermore, the increased size of the sub-gas box leads to longer gas pipes, resulting in a decrease in rapid gas exchange efficiency.

[0004] Therefore, a gas path structure design is needed that does not limit the amount of gas components and can shorten the gas path to achieve rapid gas exchange. Summary of the Invention

[0005] The purpose of this invention is to provide a plasma etching device and its gas supply components and method, which does not limit the amount of gas components and can shorten the gas path to achieve rapid gas exchange.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A gas supply assembly for introducing a first process gas and a second process gas into a reaction chamber, comprising: A gas control box is equipped with various reactive gases for configuring and forming the first process gas and the second process gas. A first gas buffer is installed on or near the top cover of the reaction chamber and connected to the gas control box for temporarily storing the first process gas configured in the gas control box. The second gas buffer is installed on or near the top cover of the reaction chamber and is connected to the gas control box for temporarily storing the second process gas configured in the gas control box. A gas switching device, wherein its input end is connected to the gas control box, its first output end is connected to the first gas buffer, and its second output end is connected to the second gas buffer; A gas delivery device, connected to the first gas buffer and the second gas buffer, is used to control the flow rates of the first process gas and the second process gas and to divert them into multiple channels with different flow rates for delivery to the reaction chamber.

[0008] Optionally, the gas delivery device includes a gas splitter and a flow control device. The flow control device includes a first flow control device and a second flow control device. One end of the first gas supply pipeline is connected to the first gas buffer and the other end is connected to the gas splitter. One end of the second gas supply pipeline is connected to the second gas buffer and the other end is connected to the gas splitter. The first flow control device and the second flow control device are respectively installed on the first gas supply pipeline and the second gas supply pipeline. A first valve and a second valve are also respectively installed on the first gas supply pipeline and the second gas supply pipeline.

[0009] Optionally, the gas delivery device includes: a mass flow splitter with flow control function and a valve, the valve including a first valve and a second valve, one end of the first gas supply pipeline is connected to the first gas buffer and the other end is connected to the mass flow splitter, one end of the second gas supply pipeline is connected to the second gas buffer and the other end is connected to the mass flow splitter, and the first valve and the second valve are respectively installed on the first gas supply pipeline and the second gas supply pipeline.

[0010] Optionally, the gas delivery device includes: a mass flow splitter with flow control function and a valve. The mass flow splitter includes a first mass flow splitter and a second mass flow splitter. The valve includes a first valve and a second valve. One end of the first gas supply pipeline is connected to the first gas buffer and the other end is connected to the first mass flow splitter. One end of the second gas supply pipeline is connected to the second gas buffer and the other end is connected to the second mass flow splitter. The first valve and the second valve are respectively installed on the first gas supply pipeline and the second gas supply pipeline.

[0011] Optionally, the gas delivery device includes a gas splitter and a flow control device. The gas splitter includes a first gas splitter and a second gas splitter. The flow control device includes a first flow control device and a second flow control device. One end of the first gas supply pipeline is connected to the first gas buffer and the other end is connected to the first gas splitter. One end of the second gas supply pipeline is connected to the second gas buffer and the other end is connected to the second gas splitter. The first flow control device and the second flow control device are respectively installed on the first gas supply pipeline and the second gas supply pipeline. A first valve and a second valve are also respectively installed on the first gas supply pipeline and the second gas supply pipeline.

[0012] Optionally, the gas switching device is a three-way valve.

[0013] Optionally, the gas control box is also configured to generate a third process gas, and the third output terminal of the gas switching device is connected to the gas delivery device for introducing the third process gas into the reaction chamber through the gas delivery device.

[0014] Optionally, the first process gas is a deposition gas, and the second process gas is an etching gas.

[0015] A plasma etching apparatus includes a reaction chamber, wherein an air supply assembly as described in any of the preceding claims is disposed outside the reaction chamber.

[0016] A gas supply method, implemented using a gas supply component as described in any of the above claims, includes the following steps: During the reaction chamber preparation stage, the gas control box sequentially configures the first process gas and the second process gas, and respectively charges the first gas buffer and the second gas buffer. During the process processing stage in the reaction chamber, the gas delivery device is controlled to alternately introduce the first process gas and the second process gas into the reaction chamber in a first cycle, and the gas control box is controlled to alternately configure the first process gas and the second process gas in a second cycle, while simultaneously controlling the gas switching device to replenish the first gas buffer and the second gas buffer. The second cycle is longer than the first cycle.

[0017] Optionally, the second period is an even multiple of the first period.

[0018] Optionally, during the second cycle, the flow rate of gas supplied by the gas control box to the first gas buffer and the second gas buffer is equal to the flow rate of gas supplied by the first gas buffer and the second gas buffer to the reaction chamber.

[0019] Optionally, before the gas control box pressurizes the first gas buffer and the second gas buffer, the pipeline between the gas control box and the first gas buffer and the second gas buffer is evacuated.

[0020] Optionally, during the pre-preparation stage of the reaction chamber, the reaction chamber may be evacuated or flushed with carrier gas.

[0021] Optionally, during the reaction chamber preparation stage, after the first and second gas buffers are filled with gas, the amount of gas inside them is at least three times the amount of the first and second process gases introduced into the reaction chamber during the second cycle.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] The gas control box and the gas delivery device are divided into two paths by a gas switching device, and a gas buffer is added to each path as a gas buffer. In this design, the gas delivery device and the two gas buffers can be placed on or near the top cover of the reaction chamber, which simplifies the structure of the gas supply components, shortens the length of the gas pipeline, and helps to achieve rapid gas switching.

[0024] To more clearly illustrate the technical solution of the present invention, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are one embodiment of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort: Simple Explanation of the Diagram

[0025] Figure 1 is a structural diagram of an existing gas supply assembly; Figure 2 is a structural diagram of another existing gas supply component; Figure 3 is a structural diagram of a first type of gas supply assembly provided in an embodiment of the present invention; Figure 4 is a structural diagram of a second gas supply assembly provided in an embodiment of the present invention; Figure 5 is a structural diagram of a third type of gas supply assembly provided in an embodiment of the present invention; Figure 6 is a structural diagram of a fourth gas supply component provided in an embodiment of the present invention; Figure 7 is a structural diagram of a fifth gas supply component provided in an embodiment of the present invention; Figure 8 is a flowchart of a gas supply method provided in an embodiment of the present invention; Figure 9 is a timing diagram of a gas supply method provided in an embodiment of the present invention. Implementation

[0026] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the proposed solution of this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to aid those skilled in the art, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0027] In the ALE process, plasma needs to switch between deposition and etching modes multiple times to achieve multi-layer atomic layer etching. This method usually uses two components of process gas to switch between each other in the reaction chamber. Therefore, the gas switching needs to be as fast as possible, while ensuring that the two components of gas do not mix with each other as much as possible during the switching.

[0028] The gas supply system of the plasma etching equipment is designed as shown in Figure 1. Multiple reactive gases are mixed within the gas control box 1 after their flow rates are controlled by multiple corresponding MFCs. Different process gases, such as etching gas and deposition gas, are then divided into 2-4 streams via a gas delivery device 2, which are respectively introduced into 2-4 gas distribution zones of the reaction chamber 3. This gas delivery device 2 can be integrated into the gas control box 1 or placed between the gas control box 1 and the reaction chamber 3. The gas control box 1 contains multiple reactive gases, each corresponding to a gas pipeline within the gas control box 1. Each gas pipeline is equipped with a corresponding MFC to regulate the flow rate of that reactive gas. The deposition gas comprises a polymer gas, a conditioning gas, and a buffer gas. The polymer gas can be one or more of the following: fluorocarbon gas (CxFy), fluorohydrocarbon gas (CxHyFz), and hydrocarbon gas (CxHy). The fluorocarbon gas can be one or more of C4F6 and C4F8. The fluorohydrocarbon gas can be one or more of CH3F and CH2F2. The hydrocarbon gas can be CH4. The conditioning gas adjusts the concentration of the polymer gas and can be gases such as O2 or N2. The buffer gas can be Ar. The etching gas typically comprises a physical etching gas and a chemical etching gas. The physical etching gas can be one or more of Ar or Kr, and the chemical etching gas can be O2. Since the etching gas and the deposition gas contain the same reactive gases, the various reactive gases from multiple reactive gas sources are mixed in proportion in the gas control box 1 to obtain the required process gas. After being divided and homogenized by the gas delivery device 2, the mixture is sent to the reaction chamber 3 for reaction.

[0029] In the current structure, the mixed process gas needs to pass through a 2-3 meter gas pipe to enter the reaction chamber 3, a process that takes approximately 1-2 seconds. This delay is too long compared to the switching frequency (2-5 seconds) required by the ALE process, failing to achieve the desired result. Furthermore, because the gas control box 1 includes numerous MFCs (one MFC for each reaction gas), its large size prevents it from being placed on or near the top cover of the reaction chamber 3 (the top cover contains numerous gas pipelines, RF pipelines, and other components). Moreover, after gas switching, both process gases may coexist at both ends of the same gas supply line, causing mixing and negatively impacting the ALE process results.

[0030] One improved method, as shown in Figure 2, involves placing the various reactive gases used for process gas preparation (two reactive gases are shown in the figure: gas 1 and gas 2) separately in a sub-gas box 4 near the top cover of the reaction chamber 3. The flow rate of each gas into each gas zone is controlled by a multi-channel MFC, achieving rapid gas intake by shortening the gas supply pipeline. However, this scheme requires eight MFCs for a configuration with two gas components and four gas distribution zones, and twelve MFCs for a configuration with three gas components and four gas distribution zones. As the number of reactive gas components increases, the number of MFCs must increase exponentially. This leads to a significant increase in cost, and the increased volume of the MFCs results in the sub-gas box 4 becoming too large to be installed near the top cover of the reaction chamber 3. Furthermore, the increased volume leads to longer gas pipelines, increasing the gas intake time and reducing the efficiency of rapid gas exchange.

[0031] Based on this, this embodiment provides an improved gas supply component gas path structure design. The gas control box and the gas delivery device are divided into two paths by a gas switching device. Then, a gas buffer is added to each path as a gas buffer. In this design, the gas delivery device and the two gas buffers are placed above or near the top cover of the reaction chamber, thereby simplifying the structure of the gas supply component, shortening the length of the gas pipeline, and helping to achieve rapid gas switching.

[0032] The gas supply assembly provided in this embodiment is used to introduce a first process gas and a second process gas into the reaction chamber. As shown in Figures 3-6, the gas supply assembly includes a gas control box 110 containing multiple reaction gases. The multiple reaction gases are mixed in the gas control box 110 after their flow rates are controlled by multiple corresponding MFCs, forming the first process gas and the second process gas. In the ALE process, the first process gas and the second process gas can be a deposition gas and an etching gas, respectively. The deposition gas includes a polymer gas, a conditioning gas, and a buffer gas. The polymer gas can be one or more of the following: fluorocarbon gas (CxFy), fluorocarbon gas (CxHyFz), and hydrocarbon gas (CxHy). The fluorocarbon gas can be one or more of the following: C4F6 and C4F8. The fluorocarbon gas can be one or more of the following: CH3F and CH2F2. The hydrocarbon gas can be CH4. The conditioning gas adjusts the concentration of the polymer gas and can be gases such as O2 and N2. The buffer gas can be Ar. The etching gas typically includes physical etching gas and chemical etching gas. The physical etching gas can be one or more of Ar or Kr, and the chemical etching gas can be O2. The gas control box 110 contains the aforementioned polymer gas, regulating gas, buffer gas, physical etching gas, and chemical etching gas. The gas control box 110 also mixes the required process gases according to process needs.

[0033] The gas supply assembly further includes: a first gas buffer 120, installed above or near the top cover of the reaction chamber 200 and connected to the gas control box 110, for temporarily storing the first process gas configured in the gas control box 110; a second gas buffer 130, installed above or near the top cover of the reaction chamber 200 and connected to the gas control box 110, for temporarily storing the second process gas configured in the gas control box 110, the two gas buffers being high-pressure resistant gas chambers with a certain volume, the volume of which can be set according to actual needs; and a gas switching device 140, the input end of which is connected to the gas control box 110, the first output end of which is connected to the first gas buffer 120, and the second output end of which is connected to the second gas buffer 130.

[0034] Optionally, the gas switching device 140 is a three-way valve, and the gas control box 110 has a gas output port. The three-way valve is connected to the gas output port of the gas control box, the first gas buffer 120, and the second gas buffer 130. In some other embodiments, the gas switching device 140 may also be two two-way valves. The gas control box 110 has two gas output ports, and the two two-way valves are respectively connected to the two gas output ports of the gas control box 110, the first gas buffer 120, and the second gas buffer 130.

[0035] The gas supply assembly further includes a gas delivery device 150, which connects the first gas buffer 120 and the second gas buffer 130, for controlling the flow rates of the first process gas and the second process gas and diverting them into multiple channels with different flow rates to deliver to different areas of the reaction chamber 200.

[0036] In this embodiment, when the gas supply assembly is working, by controlling the on / off state of the two output terminals of the gas switching device 140, the gas control box 110 mixes the required process gas and supplies gas to the first gas buffer 120 and the second gas buffer 130 respectively. The two premixed process gases are pre-charged into the first gas buffer 120 and the second gas buffer 130 respectively. By controlling the gas delivery device 150, the two different process gases in the first gas buffer 120 and the second gas buffer 130 are delivered to the reaction chamber 200 respectively.

[0037] In this embodiment, the gas supply assembly only requires placing two gas buffers and a gas delivery device above or near the chamber top cover, which greatly saves space and enables rapid gas exchange. By adding two gas buffers, this embodiment significantly simplifies the gas path design near the chamber top cover in the gas supply assembly, achieving rapid gas switching with the simplest design. At the same time, it reduces the pressure of switching the working mode of the gas control box, greatly improving the working efficiency of the existing gas path without changing the existing gas path design structure as much as possible.

[0038] In some other embodiments, multiple gas buffers may be provided according to process requirements.

[0039] As shown in Figure 3, the first structure of the gas delivery device 150 includes a gas splitter 151 and a flow control device 152. The flow control device 152 includes a first flow control device 1521 and a second flow control device 1522. One end of the first gas supply pipeline 1531 is connected to the first gas buffer 120, and the other end is connected to the gas splitter 151. One end of the second gas supply pipeline 1532 is connected to the second gas buffer 130, and the other end is connected to the gas splitter 151. The first flow control device 1521 and the second flow control device 1522 are respectively installed on the first gas supply pipeline 1531 and the second gas supply pipeline 1532. A first valve 1541 and a second valve 1542 are also respectively installed on the first gas supply pipeline 1531 and the second gas supply pipeline 1532.

[0040] In this embodiment, the gas splitter 151 can only supply gas to multiple locations in the reaction chamber 200 in sections, but cannot control the flow rate of each path. Therefore, a first flow control device 1521 and a second flow control device 1522 are needed between the first gas buffer 120 / second gas buffer 130 and the gas splitter 151 for flow control. A first valve 1541 and a second valve 1542 are connected between the first flow control device 1521 and the second flow control device 1522 and the gas splitter 151 respectively to achieve complete shut-off and switch between the two process gases. The first flow control device 1521 and the second flow control device 1522 can be an MFC, or a throttling orifice, or a throttling valve.

[0041] As shown in Figure 4, the second structure of the gas delivery device 150 includes a mass flow splitter 155 with flow control function and a valve 154. The valve 154 includes a first valve 1541 and a second valve 1542. One end of the first gas supply pipeline 1531 is connected to the first gas buffer 120 and the other end is connected to the mass flow splitter 155. One end of the second gas supply pipeline 1532 is connected to the second gas buffer 130 and the other end is connected to the mass flow splitter 155. The first valve 1541 and the second valve 1542 are respectively installed on the first gas supply pipeline 1531 and the second gas supply pipeline 1532.

[0042] In this embodiment, the mass flow splitter 155 can both split and control the flow rate, and the gas switching is achieved by the first valve 1541 and the second valve 1542. The mass flow splitter 155 may include multiple MFCs (in this embodiment, since there are two process gases, two MFCs are set to control their respective flow rates) to achieve the flow control function. In some other embodiments, multiple throttling orifices or multiple throttling valves may also be provided on each gas pipeline to achieve the flow control function.

[0043] Furthermore, since the internal structure of the gas splitter 151 and the mass flow splitter 155 may be relatively complex, in the structure shown in Figures 3 and 4, when the two process gases share a set of gas splitter 151 and mass flow splitter 155, the residual gas in the gas splitter 151 and mass flow splitter 155 may cause the two gases to mix.

[0044] Therefore, as shown in Figure 5, the third structure of the gas delivery device 150 includes: a mass flow splitter 155 with flow control function and a valve 154. The mass flow splitter 155 includes a first mass flow splitter 1551 and a second mass flow splitter 1552. The valve 154 includes a first valve 1541 and a second valve 1542. One end of the first gas supply pipeline 1531 is connected to the first gas buffer 120 and the other end is connected to the first mass flow splitter 1551. One end of the second gas supply pipeline 1532 is connected to the second gas buffer 130 and the other end is connected to the second mass flow splitter 1552. The first valve 1541 and the second valve 1542 are respectively installed on the first gas supply pipeline 1531 and the second gas supply pipeline 1532.

[0045] It is understood that, based on the embodiment in Figure 4, a separate mass flow splitter 155 is provided for each gas buffer to ensure that no gas mixing process occurs within the mass flow splitter 155, thereby improving gas switching efficiency and avoiding cross-contamination between the two process gases.

[0046] As shown in Figure 6, the fourth structure of the gas delivery device 150 includes a gas splitter 151 and a flow control device 152. The gas splitter 151 includes a first gas splitter 1511 and a second gas splitter 1512. The flow control device 152 includes a first flow control device 1521 and a second flow control device 1522. One end of the first gas supply pipeline 1531 is connected to the first gas buffer 120 and the other end is connected to the first gas splitter 1511. One end of the second gas supply pipeline 1532 is connected to the second gas buffer 130 and the other end is connected to the second gas splitter 1512. The first flow control device 1521 and the second flow control device 1522 are respectively installed on the first gas supply pipeline 1531 and the second gas supply pipeline 1532. A first valve 1541 and a second valve 1542 are also respectively installed on the first gas supply pipeline 1531 and the second gas supply pipeline 1532.

[0047] It is understood that, based on the embodiment in Figure 3, a separate gas splitter 151 is provided for each gas buffer to ensure that no gas mixing process occurs within the gas splitter 151, thereby improving gas switching efficiency and avoiding cross-contamination between the two process gases.

[0048] The gas supply assembly provided in this embodiment can conveniently provide rapid gas supply for performing ALE process steps in plasma etching equipment. However, when it is necessary to perform conventional process (non-rapid gas switching) steps in plasma etching equipment, usually only one gas supply path needs to be selected. At this time, it is necessary to quickly empty the residual gas in the gas buffer in that path, and also to quickly fill the gas buffer with the gas required for the conventional process to a pressure sufficient for the subsequent MFC. This not only leads to a longer time to enter the conventional process step, but also brings the risk of gas component contamination.

[0049] Therefore, to facilitate the free switching between ALE and conventional processes in plasma etching equipment, the structural diagram of another gas supply component provided in this embodiment is shown in Figure 7. Based on the embodiment shown in Figure 3, the gas control box 110 is used to configure the formation of a third process gas. The gas supply component also includes a bypass gas path 156. The gas switching device 140 also has a third output terminal. The third output terminal is connected to the first end of the bypass gas path 156, and the second end of the bypass gas path 156 is connected to the gas splitter 151, which introduces the third process gas into the reaction chamber 200. Optionally, the gas switching device 140 can be a four-way valve or a combination of two three-way valves. An additional bypass gas path 156 for the conventional process gas is added between the gas switching device 140 and the gas delivery device 150. The first end of the bypass gas path 156 is connected to the third output terminal of the gas switching device 140, and the second end of the bypass gas path 156 is directly connected to the gas splitter 151. In some embodiments, the bypass gas path 156 has no gas buffer, operating in the same manner as existing plasma etching equipment. The gas delivery device 150 may also omit the flow control valve, with the total flow rate entirely controlled by the gas control box 110. This allows for quick switching to the bypass gas path 156 via the valve in the gas switching device 140, or simultaneous execution of conventional process steps while using the purging gas in the gas control box 110 to clean the gas buffers on both ALE gas paths, preventing residual process gas in the two pipelines. The bypass gas path 156 can also be configured as shown in the embodiments illustrated in Figures 4, 5, and 6, and will not be elaborated upon here.

[0050] Based on the same inventive concept, this embodiment also provides a gas supply method, which is implemented using the above-mentioned gas supply component, as shown in Figure 8, and specifically includes the following steps:

[0051] Step S1: In the reaction chamber pre-preparation stage, the gas control box sequentially configures the first process gas and the second process gas and respectively charges the first gas buffer and the second gas buffer;

[0052] Step S2: During the process treatment stage in the reaction chamber, the gas delivery device is controlled to alternately introduce the first process gas and the second process gas into the reaction chamber in a first cycle, and the gas control box is controlled to alternately configure the first process gas and the second process gas in a second cycle, while simultaneously controlling the gas switching device to replenish the first gas buffer and the second gas buffer. The second cycle is longer than the first cycle.

[0053] Referring to the timing diagram of the introduction of the first process gas (deposition gas) and the second process gas (etching gas) in the ALE process of one embodiment shown in Figure 9, the above steps S1 and S2 will be described in detail.

[0054] In Figure 9, time period T1 (corresponding to step S1) is the pre-preparation stage, which is the preparation stage before the ALE process. Its main objective is to fill the first gas buffer and the second gas buffer with the first process gas and the second process gas required for the ALE process, respectively. During this time period, the reaction chamber can be evacuated, or pressure gas or carrier gas can be introduced for flushing.

[0055] Time period T1 includes sub-time periods t1 and t2. During sub-time period t1, the gas control box mixes and outputs the first process gas components, and the first output terminal of the gas switching device supplies gas to the first gas buffer. During this time period, the flow rate of the first process gas output by the gas control box can be very large, achieving rapid inflation of the first gas buffer and quickly bringing the pressure of the first process gas in the first gas buffer to the pressure value P(MFC) that allows the MFC to operate normally.

[0056] During the t2 sub-period, the gas control box mixes and outputs the second process gas components, and the gas switching device switches the second output terminal to supply gas to the second gas buffer. The working mode is similar to that of the t1 sub-period.

[0057] After the first and second gas buffers are inflated, the amount of gas inside them is at least three times greater than the amount of the first and second process gases introduced into the reaction chamber during the first cycle. It can be understood that when the gas control box inflates the gas buffers, the mass of gas inside the gas buffers is much greater than the mass of gas drawn from the reaction chamber from the gas buffers during the next non-inflating period. This ensures sufficient gas pressure within the gas buffers, facilitating faster input of process gas into the reaction chamber to meet its process gas requirements.

[0058] To prevent the two process gases from mixing in the pipeline between the gas control box and the gas buffer, a vacuum is evacuated from the pipeline between the gas control box and the first and second gas buffers before the gas control box charges them. The vacuuming time can be 1-5 seconds. Due to the presence of the gas buffers, this 1-5 second evacuation process will not affect the production process.

[0059] The T2 period (corresponding to step S2) is the ALE process stage. During this period, the first process gas and the second process gas are alternately introduced into the reaction chamber for plasma etching at the required cycle (i.e., the first cycle TALE, 6 seconds in Figure 9) by the first gas buffer and the second gas buffer, respectively, controlled by the switching of the first flow control device and the second flow control device. Their flow rates are QALE (first process gas) and QALE (second process gas), respectively. In Figure 9, the two process gases switch every 3 seconds, and the gas composition in the reaction chamber changes periodically with the above-mentioned cyclic gas supply.

[0060] On the other hand, to compensate for the pressure drop in the first and second gas buffers caused by gas outflow, the gas control box and the gas switching device work together to replenish gas to the first and second gas buffers at longer intervals (i.e., the second cycle T gas source, 60 seconds in Figure 9). Simultaneously, to ensure relatively stable gas pressure in the first and second gas buffers, within each second cycle, the flow rate of the first process gas input to the first gas buffer from the gas control box should be equal to QALE (first process gas), and the flow rate of the second process gas input to the second gas buffer should also be equal to QALE (second process gas).

[0061] In this embodiment, the second cycle is an even multiple of the first cycle to ensure that the gas pressure in the two gas buffers will not continuously rise or fall during a long process, but will only fluctuate within a small range around a central value, thereby ensuring the stability of the entire gas path.

[0062] Understandably, in the ALE process, the gas supply cycle for the first and second process gases to the reaction chamber is determined by the ALE process itself. To improve production efficiency, this cycle is typically very short, on the order of a few seconds. For rapid switching of multiple process gases, if the gas control box is required to operate with the short cycle of the ALE process, multiple MFCs in the gas control box must switch on and off rapidly together. The more MFCs working together, the more difficult it is to synchronize the timing. On the other hand, if some of the required gas components have very high flow rates and others have very low flow rates, the flow overshoot of the high-flow-rate gas will be much greater than that of the low-flow-rate gas when the MFC controlling the high-flow-rate gas opens. This results in a significant difference between the gas composition output by the gas control box in the first few tenths of a second after each opening and the following few seconds. As the ALE process requires increasingly faster gas switching cycles, this compositional difference will have an increasingly greater impact on the actual gas composition introduced into the reaction chamber.

[0063] In this embodiment, the gas control box uses a long cycle to supply gas to the gas buffer, while the gas buffer uses a short cycle to supply gas to the reaction chamber. This reduces the requirements for the coordinated operation of multiple MFCs in the gas control box. The time difference of a few tenths of a second between the switching on and off of multiple MFCs, or the gas composition changes caused by different flow overshoot values ​​during switching, are also very low compared to the stable gas supply over the following tens of seconds. The presence of the gas buffer can further weaken the gas composition fluctuations caused by these unstable factors.

[0064] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0065] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above. Therefore, the scope of protection of the present invention should be defined by the appended claims.

[0066] 1: Gas control box 2: Gas conveying device 3: Reaction Chamber 4: Sub-gas box 110: Gas Control Box 120: First gas buffer 130: Second Gas Buffer 140: Gas switching device 150: Gas conveying device 151: Gas splitter 1511: First Gas Splitter 1512: Second gas splitter 152: Flow control device 1521: First Flow Control Device 1522: Second Flow Control Device 1531: First gas supply pipeline 1532: Second gas supply pipeline 154: Valves 1541: First Valve 1542: Second valve 155: Mass Flow Splitter 1551: First mass flow splitter 1552: Second mass flow splitter 156: Bypass gas path 200: Reaction Chamber S1: Steps S2: Steps T1: Time Period T2: Time Period t1: Sub-period t2: Sub-period TALE: First Cycle Gas source T: Second cycle P(MFC): Pressure value

Claims

1. A gas supply assembly for introducing a first process gas and a second process gas into a reaction chamber, comprising: A gas control box having multiple reactive gases, used to alternately configure the first process gas and the second process gas in a second cycle; The first gas buffer is installed above or near the top cover of the reaction chamber and connected to the gas control box for temporarily storing the first process gas configured in the gas control box. A second gas buffer is installed above or near the top cover of the reaction chamber and connected to the gas control box for temporarily storing the second process gas configured in the gas control box; a gas switching device has its input end connected to the gas control box, its first output end connected to the first gas buffer, and its second output end connected to the second gas buffer; the first output end and the second output end are alternately connected to the input end so that the first process gas flows into the first gas buffer and the second process gas flows into the first gas buffer. A gas delivery device, connected to the first gas buffer and the second gas buffer, is used to control the flow rates of the first process gas and the second process gas and to divert them into multiple channels with different flow rates to the reaction chamber. The gas delivery device alternately introduces the first process gas and the second process gas into the reaction chamber in a first cycle, the first cycle being shorter than the second cycle.

2. The gas supply assembly as described in claim 1, wherein, The gas delivery device includes a gas splitter and a flow control device. The flow control device includes a first flow control device and a second flow control device. One end of the first gas supply pipeline is connected to the first gas buffer and the other end is connected to the gas splitter. One end of the second gas supply pipeline is connected to the second gas buffer and the other end is connected to the gas splitter. The first flow control device and the second flow control device are respectively installed on the first gas supply pipeline and the second gas supply pipeline. A first valve and a second valve are also respectively installed on the first gas supply pipeline and the second gas supply pipeline.

3. The gas supply assembly as described in claim 1, wherein, The gas delivery device includes a mass flow splitter with flow control function and a valve. The valve includes a first valve and a second valve. One end of the first gas supply pipeline is connected to the first gas buffer and the other end is connected to the mass flow splitter. One end of the second gas supply pipeline is connected to the second gas buffer and the other end is connected to the mass flow splitter. The first valve and the second valve are respectively installed on the first gas supply pipeline and the second gas supply pipeline.

4. The gas supply assembly as described in claim 1, wherein, The gas delivery device includes a mass flow splitter and a valve with flow control function. The mass flow splitter includes a first mass flow splitter and a second mass flow splitter. The valve includes a first valve and a second valve. One end of a first gas supply pipeline is connected to the first gas buffer and the other end is connected to the first mass flow splitter. One end of a second gas supply pipeline is connected to the second gas buffer and the other end is connected to the second mass flow splitter. The first valve and the second valve are respectively installed on the first gas supply pipeline and the second gas supply pipeline.

5. The gas supply assembly as described in claim 1, wherein, The gas delivery device includes a gas splitter and a flow control device. The gas splitter includes a first gas splitter and a second gas splitter. The flow control device includes a first flow control device and a second flow control device. One end of the first gas supply pipeline is connected to the first gas buffer and the other end is connected to the first gas splitter. One end of the second gas supply pipeline is connected to the second gas buffer and the other end is connected to the second gas splitter. The first flow control device and the second flow control device are respectively installed on the first gas supply pipeline and the second gas supply pipeline. A first valve and a second valve are also respectively installed on the first gas supply pipeline and the second gas supply pipeline.

6. The gas supply assembly as described in claim 1, wherein, The gas switching device is a three-way valve.

7. The gas supply assembly as described in any one of claims 1 to 6, wherein, The gas control box is also used to configure the formation of a third process gas. The gas supply assembly also includes a bypass gas path. The gas switching device also has a third output terminal. The third output terminal is connected to the first end of the bypass gas path, and the second end of the bypass gas path is connected to the gas delivery device for introducing the third process gas into the reaction chamber through the gas delivery device.

8. The gas supply assembly as described in any one of claims 1 to 6, wherein, The first process gas is a deposition gas, and the second process gas is an etching gas.

9. A plasma etching apparatus, comprising a reaction chamber, wherein an air supply assembly as described in any one of claims 1 to 8 is disposed outside the reaction chamber.

10. A gas supply method, wherein, The gas supply assembly described in any one of claims 1 to 8 is used, comprising the following steps: During the reaction chamber pre-preparation stage, the gas control box sequentially configures the first process gas and the second process gas and respectively charges the first gas buffer and the second gas buffer; During the reaction chamber processing stage, the gas delivery device is controlled to alternately supply the first process gas and the second process gas to the reaction chamber in a first cycle, and the gas control box is controlled to alternately configure the first process gas and the second process gas in a second cycle while simultaneously controlling the gas switching device to replenish the first gas buffer and the second gas buffer, wherein the second cycle is longer than the first cycle.

11. The gas supply method as described in claim 10, wherein, The second period is an even multiple of the first period.

12. The gas supply method as described in claim 10, wherein, During the second cycle, the flow rate of gas supplied by the gas control box to the first gas buffer and the second gas buffer is equal to the flow rate of gas supplied by the first gas buffer and the second gas buffer to the reaction chamber.

13. The gas supply method as described in claim 10, wherein, Before the gas control box pressurizes the first gas buffer and the second gas buffer, the pipeline between the gas control box and the first gas buffer and the second gas buffer is evacuated.

14. The gas supply method as described in claim 10, wherein, During the pre-preparation stage of the reaction chamber, the reaction chamber is evacuated or flushed with carrier gas.

15. The gas supply method as described in claim 10, wherein, During the pre-preparation phase of the reaction chamber, after the first gas buffer and the second gas buffer are filled, the amount of gas inside them is at least three times greater than the amount of the first process gas and the second process gas introduced into the reaction chamber during the first cycle.

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