Atomic layer etching method and device
By controlling the gas venting and power application sequence in the atomic layer etching method, the problems of etching accuracy and efficiency were solved, achieving high-precision and high-efficiency etching results.
Patent Information
- Application Number
- CN202410607157.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-15
- Publication Date
- 2025-11-18
AI Technical Summary
In existing atomic layer etching equipment, there is a gap between the gas response speed and the etching process requirements, resulting in low etching accuracy. Furthermore, the gas delay response and gas exchange efficiency affect the accurate transfer of patterns and size control, resulting in a load effect.
In the atomic layer etching method, multiple cycles are performed sequentially. Each cycle includes introducing deposition gas and etching gas, applying excitation power to form a first plasma and a second plasma, stopping the deposition gas, venting the unadsorbed first plasma after a preset time, and then applying bias power for etching. The process parameters are adjusted to avoid gas mixing.
It improves etching precision and process control capabilities, enabling precise control of substrate patterns and dimensions, avoiding over-etching and damage to components inside the reaction chamber, and improving etching efficiency.
Smart Images
Figure CN120977896A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of semiconductor manufacturing, and in particular to an atomic layer etching method and device. BACKGROUND
[0002] In the process of semiconductor manufacturing, with the reduction of feature size and the refinement of pattern, the requirement for etching process is further improved, and the atomic layer etching (ALE) process emerges as the times require.
[0003] The atomic layer etching process is a technology for removing atomic layer of substrate by self-limiting reaction, which usually has multiple cycles, and each cycle generally includes a modification step and an etching step. In the modification step, a deposition gas is introduced, and the deposition gas only combines with single layer or multiple layers of atoms on the surface of the substrate, so that the chemical properties of the atoms on the surface of the substrate are changed. In the etching step, an etching gas is introduced and ionized, and the plasma generated by ionization bombards the atoms on the modified surface of the substrate, so that the single layer or multiple layers of atoms on the modified surface of the substrate are desorbed, thereby realizing atomic layer etching.
[0004] However, there is a large gap between the response speed of the gas used in the atomic layer etching process and the requirement of the etching process for the existing device. The delay response and gas exchange efficiency of the gas affect the process precision of ALE, and further limit the accurate transmission of the pattern and the precise control of the size, and a large loading effect is easily generated between different patterns. Further, since the length of the gas pipeline connecting the gas source and the reaction chamber is relatively long, there is a time difference between the gas supply instruction issued by the controller and the actual arrival of the gas in the reaction chamber, which causes a phase difference between the response speed of the gas and the output of the radio frequency power, resulting in a long mixing process of the modification and etching process of the atomic layer etching, and the delay response and gas exchange efficiency of the gas affect the process precision of ALE. Therefore, it is necessary to adjust the atomic layer etching method and device. SUMMARY
[0005] The purpose of the present application is to provide an atomic layer etching method and device, which can avoid the long mixing of process gas used in the adsorption modification process and the etching process in atomic layer etching, thereby meeting the requirement of atomic layer etching process for etching precision and improving the control ability of etching process.
[0006] In order to achieve the above purpose, the present application realizes the following technical scheme:
[0007] An atomic layer etching method, comprising: multiple cycles performed in sequence; each cycle comprising:
[0008] introducing a deposition gas and an etching gas into the reaction chamber;
[0009] applying an excitation power to ionize the deposition gas into a first plasma and to ionize the etching gas into a second plasma; and the first plasma modifying atoms of the substrate surface in the reaction chamber to form a modified layer;
[0010] stopping the deposition gas and applying a bias power after a first preset time period to control the second plasma to etch the modified layer; and
[0011] stopping the bias power;
[0012] wherein the first preset time period is at least for the first plasma not adsorbed after forming the modified layer to be exhausted.
[0013] Optionally, in a first cycle of the plurality of cycles, the excitation power is applied after a second preset time period after the deposition gas is introduced; and in a non-first cycle of the plurality of cycles, the excitation power is continuously applied.
[0014] Optionally, the excitation power has a first power value in the first preset time period and a second power value in a non-first preset time period after the excitation power is applied, the first power value being 20% to 50% of the second power value.
[0015] Optionally, the second preset time period is at least for the deposition gas to enter the reaction chamber from a gas source through a gas pipeline.
[0016] Optionally, the first plasma is in a steady state when an absolute value of a variation amplitude of a light intensity of the first plasma is not more than a set threshold value after the light intensity of the first plasma is normalized in a set time period, and an average value of the light intensity of the first plasma in the set time period is a steady state intensity.
[0017] The first plasma not adsorbed after forming the modified layer is exhausted when a light intensity of the first plasma is less than 10% of a steady state intensity of the first plasma after the deposition gas is stopped.
[0018] Optionally, the set time period is 0s to 5s, and the set threshold value is 0 to 5%.
[0019] Optionally, each cycle further comprises: adjusting a process parameter in a first transition time period after the bias power is stopped.
[0020] Optionally, the process parameter comprises a flow rate of the etching gas and a pressure of the reaction chamber.
[0021] Optionally, the excitation power is higher than the bias power.
[0022] Optionally, the excitation power is high frequency and the bias power is low frequency.
[0023] Optionally, the deposition gas is C x H y F z gas, C a F b gas or C m H n gas, wherein x, y, z, a, b, m, n are not 0.
[0024] Optionally, the deposition gas is C x H y F z gas or C a F b When the deposition gas is gas, the etching gas is argon or krypton;
[0025] The deposition gas is C m H n When the deposition gas is gas, the etching gas includes one of argon and krypton and oxygen-containing gas.
[0026] In another aspect, the present application also provides an atomic layer etching method, comprising: multiple cycles performed in sequence; each cycle comprises:
[0027] introducing deposition gas and etching gas into a reaction chamber;
[0028] applying excitation power to ionize the deposition gas into a first plasma and ionize the etching gas into a second plasma; and the first plasma modifies atoms on a substrate surface in the reaction chamber to form a modified layer;
[0029] stopping the introduction of the deposition gas, and after a third preset time period, applying bias power to control the second plasma to etch the modified layer; and
[0030] stopping the application of the bias power;
[0031] wherein the third preset time period is greater than a time period required for evacuating the first plasma that is not adsorbed after the formation of the modified layer, so as to delay etching the modified layer; and the third preset time period includes a second transition time period and a lag time period;
[0032] adjusting process parameters in the second transition time period, and waiting for etching the modified layer in the lag time period; and in both the second transition time period and the lag time period, the deposition gas that is not adsorbed after the formation of the modified layer is pumped until evacuated.
[0033] Optionally, the second transition duration is 1s-2s.
[0034] Optionally, the hysteresis duration is 100ms-2s.
[0035] In another aspect, the present application also provides an atomic layer etching device for implementing the atomic layer etching method as described above; the atomic layer etching device comprises:
[0036] a reaction cavity;
[0037] a gas inlet device arranged at the inner top of the reaction cavity and used for introducing deposition gas and etching gas into the reaction cavity;
[0038] a susceptor arranged at the inner bottom of the reaction cavity and used for carrying a substrate;
[0039] a first radio frequency source used for outputting excitation power;
[0040] a second radio frequency source used for outputting bias power;
[0041] a controller electrically connected with the first radio frequency source and the second radio frequency source, used for controlling the first radio frequency source to start applying excitation power to the reaction cavity and stop applying the excitation power, and also used for controlling the second radio frequency source to start applying bias power to the reaction cavity and stop applying the bias power.
[0042] Optionally, the atomic layer etching device further comprises a light intensity detection device arranged in the interior of the reaction cavity and electrically connected with the controller, used for detecting the light intensity of the first plasma and sending to the controller.
[0043] Compared with the prior art, the present application has at least one of the following advantages:
[0044] The atomic layer etching method and device provided by the present application, the atomic layer etching method comprises a plurality of cycles performed in sequence, and each cycle comprises: introducing deposition gas and etching gas into the reaction cavity; then ionizing the deposition gas into a first plasma and ionizing the etching gas into a second plasma by applying excitation power, and the first plasma modifies a single layer or multiple layers of atoms on the surface of the substrate in the reaction cavity and forms a modified layer; then stop introducing the deposition gas, and after a first preset duration, start applying bias power to control the second plasma to etch the modified layer. Wherein, the first preset duration at least evacuates the first plasma that is not adsorbed after the modified layer is formed, so that there is no first plasma in the reaction cavity when the bias power is applied, so as to avoid the mixing of the first plasma and the second plasma to form a mixed gas with extremely strong reaction activity when the bias power is applied, causing over-etching of the substrate, thereby meeting the requirement of etching precision of the atomic layer etching process and improving the control ability of the etching process.
[0045] In the present application, the bias power can be applied after the deposition gas is stopped and a third preset time period elapses, the third preset time period is longer than the time period required for exhausting the first plasma not adsorbed after the modified layer is formed, so as to delay the etching step; and the third preset time period comprises a second transition time period and a lag time period, the process parameters are adjusted in the second transition time period, and the etching of the modified layer is waited in the lag time period. The lag time period is set to facilitate the precise and independent control of the etching process, so as to realize the precise control of the pattern and size on the substrate, and further meet the process requirement of very small etching amount. In addition, by reasonably adjusting the length relationship between the second transition time period and the lag time period, the cycle of a single cycle can be effectively shortened, so as to effectively improve the efficiency of atomic layer etching.
[0046] Compared with the operation of simultaneously starting the gas source and applying the excitation power in the prior art, the present application starts to apply the excitation power after the deposition gas completely enters the reaction chamber in the first cycle, that is, the time of starting the gas source is separated from the time of applying the excitation power by a second preset time period. In this way, the adsorption modification process can be precisely controlled, and the over-etching of the substrate and the damage to other components in the reaction chamber caused by the early application of the excitation power can be avoided.
[0047] After the bias power is stopped, the process parameters are adjusted in the first transition time period, so that the process parameters meet the process requirements of the next cycle, thereby effectively improving the efficiency of atomic layer etching. BRIEF DESCRIPTION OF DRAWINGS
[0048] Figure 1 is a flowchart of an atomic layer etching method provided by an embodiment of the present application;
[0049] Figure 2 is a timing diagram of an atomic layer etching method provided by an embodiment of the present application;
[0050] Figure 3 is a timing diagram of light intensity of the first plasma in an atomic layer etching method provided by an embodiment of the present application;
[0051] Figure 4 is a timing diagram of an atomic layer etching method provided by an embodiment of the present application;
[0052] Figure 5 is a flowchart of an atomic layer etching method provided by an embodiment of the present application;
[0053] Figure 6 is a timing diagram of an atomic layer etching method provided by an embodiment of the present application;
[0054] Figure 7is a structural schematic diagram of an atomic layer etching device provided by the present application. DETAILED DESCRIPTION
[0055] The atomic layer etching method and device provided by the present application are described in further detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present application will be more apparent from the following description. It should be noted that the accompanying drawings are very simplified and all use non-precise proportions, and are only used to facilitate and clarify the purpose of assisting the description of the embodiments of the present application. In order to make the purpose, features and advantages of the present application more apparent and easy to understand, please refer to the accompanying drawings. It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to the present specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and are not used to limit the conditions for implementing the present application, so they do not have technical substantive significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.
[0056] It should be noted that in this document, relational terms such as first and second and the like can only be used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed or inherent to such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus including the element.
[0057] Embodiment one
[0058] In conjunction with the accompanying Figures 1-3As shown, the embodiment provides an atomic layer etching method for etching a substrate in a reaction chamber; the atomic layer etching method comprises a plurality of cycles performed sequentially; each cycle comprises: step S1, introducing deposition gas and etching gas into the reaction chamber; step S2, applying excitation power to ionize the deposition gas into a first plasma and ionize the etching gas into a second plasma; and the first plasma modifies atoms on the surface of the substrate in the reaction chamber to form a modified layer; step S3, stopping the introduction of the deposition gas, and after a first preset time, applying a bias power to control the second plasma to bombard and etch the modified layer; and step S4, stopping the application of the bias power; wherein the first preset time is at least long enough to evacuate the first plasma that is not adsorbed after the formation of the modified layer.
[0059] Specifically, the deposition gas and the etching gas are stored in different gas sources, and each gas source is communicated with the reaction chamber through a gas pipeline to deliver the deposition gas and the etching gas into the reaction chamber. Under the action of the excitation power, the deposition gas is ionized into the first plasma, and the first plasma can have a deposition reaction with the atoms on the surface of the substrate, thereby modifying the single-layer or multi-layer atoms on the surface of the substrate and forming the modified layer. This process (including steps S1 and S2) can be referred to as an adsorption modification process.
[0060] The etching gas is ionized into the second plasma under the action of the excitation power. Further, under the action of the bias power, the second plasma is accelerated and guided to the substrate and bombards the modified layer to etch the modified layer, thereby achieving etching of the substrate. This process (including steps S3 and S4) can be referred to as an etching process. Optionally, the excitation power is higher than the bias power, so that the excitation power serves as a source power for exciting the plasma. Optionally, the excitation power is high frequency, which can be, for example, a frequency of 13.56 MHz, 27 MHz or 60 MHz; and the bias power is low frequency, which can be, for example, a frequency less than or equal to 400 kHz. In addition, the corresponding deposition gas and etching gas will be different when the target of atomic layer etching on the substrate is different; for example, when the target of atomic layer etching on the substrate is silicon nitride, the deposition gas is C x H y F z gas (where x, y, z are not 0), preferably CH3F gas, and the etching gas is argon or krypton. When the target of atomic layer etching on the substrate is silicon oxide, the deposition gas is C a F bThe gas (wherein a, b are not 0) can be preferably C4F6 gas; the etching gas is argon or krypton. When the target of the atomic layer etching on the substrate is a carbon film, the deposition gas is C m H n The gas (wherein m, n are not 0) can be preferably CH4 gas; the etching gas not only includes one of argon and krypton, but also includes an oxygen-containing gas, preferably, the oxygen-containing gas is oxygen, but the present application is not limited thereto.
[0061] In the embodiment, after the modified layer is formed on the substrate, the deposition gas is stopped from being introduced into the reaction chamber, and the bias power is applied after the first preset time period after the deposition gas is stopped, so that the first plasma not adsorbed after the modified layer is formed can be exhausted by using a gas exhaust pump in the first preset time period, so that there is no first plasma in the reaction chamber when the bias power is applied, and only the second plasma or the mixture of the second plasma and the etching gas exists, so as to avoid the mixing of the first plasma and the second plasma when the bias power is applied, thereby avoiding the mixing of the process gas used in the adsorption modification process and the etching process in the atomic layer etching, and further avoiding the formation of the mixed gas with extremely strong reactivity in the reaction chamber to cause over-etching of the substrate, so as to meet the requirement of etching precision of the atomic layer etching process and improve the control ability of the etching process.
[0062] In addition, in the embodiment, the light intensity detection device is arranged in the reaction chamber, and the light intensity detection device can be used to detect the light intensity of the first plasma in the reaction chamber, so as to accurately judge whether the first plasma is exhausted. Specifically, as shown in FIG. 2, the light intensity detection device is arranged on the side wall of the reaction chamber, and the light intensity detection device is arranged to be perpendicular to the direction of the first plasma flow. Figure 3As shown, after the deposition gas is introduced, if the absolute value of the change amplitude of the light intensity of the first plasma after normalization within a set time period does not exceed a set threshold value, the first plasma is in a steady state, and the average value of the light intensity of the first plasma within the set time period is the steady state intensity thereof; further, after the introduction of the deposition gas is stopped, if the light intensity of the first plasma is detected to be less than 10% of the steady state intensity thereof, it is considered that the first plasma not adsorbed after the modification layer is exhausted. More specifically, the first preset time period is related to factors such as the pumping rate and the volume of the reaction chamber, and in some embodiments, the value of the first preset time period can also be determined by multiple light intensity detections of the first plasma or exhaustion experiments of the first plasma. Optionally, the first preset time period is set to 1s-3s; preferably, the first preset time period is set to 2s. Optionally, the set time period is 0s-5s, and the set threshold value is 0-5%; preferably, the set time period is 2s, and the set threshold value is 2%. Optionally, the light intensity detection device is an OES spectrometer, but the present application is not limited thereto.
[0063] Please continue to refer to Figure 2 In the first cycle of the plurality of cycles, i.e. the starting stage of each process, the excitation power is applied after a second preset time period T1 after the introduction of the deposition gas; in the non-first cycle (for example, the second cycle) of the plurality of cycles, the excitation power is continuously applied.
[0064] Specifically, the second preset time period T1 at least allows the deposition gas to enter the reaction chamber from the gas source through the gas pipeline, i.e. ensures that the excitation power is applied after the deposition gas completely enters the reaction chamber, so as to modify the atoms on the surface of the substrate. Optionally, the second preset time period T1 is exactly the time period required for the deposition gas to completely enter the reaction chamber from the gas source; and the second preset time period T1 is usually related to factors such as the length of the gas pipeline, the flow rate of the deposition gas, etc. In some embodiments, the light intensity detection device can also be used to detect the light intensity of the deposition gas in the reaction chamber, and when the light intensity signal of the deposition gas is detected, it indicates that the deposition gas completely enters the reaction chamber from the gas source through the gas pipeline; for example, the second preset time period T1 is set to 1s-3s; preferably, the second preset time period T1 is set to 2s. Figure 3As shown, after the second preset time length T1, the light intensity signal of the deposition gas in the reaction chamber is detected at time A, and then the excitation power is applied to excite the first plasma. Further, the value of the second preset time length can be determined by multiple light intensity detections of the deposition gas or experiments of the deposition gas. Optionally, the second preset time length T1 is set to 1s-3s; preferably, the second preset time length T1 is set to 2s, but the present application is not limited thereto.
[0065] Specifically, compared with the prior art of synchronously performing the operations of opening the gas source and applying the excitation power, the embodiment starts to apply the excitation power after the deposition gas completely enters the reaction chamber in the first cycle, that is, the time of opening the gas source is separated from the time of applying the excitation power by the second preset time length T1, so that the adsorption modification process can be accurately controlled, and the over-etching of the substrate and the damage to other components in the reaction chamber caused by the early application of the excitation power can be avoided.
[0066] Specifically, after the excitation power is started to be applied, the excitation power is continuously applied until the multiple cycles are completed, so that the etching gas can be continuously ionized into the second plasma to prevent the second plasma in the reaction chamber from being broken off, thereby being able to prepare for the etching process and achieving the etching of the modification layer at the moment of starting to apply the bias power, and then accurately controlling the etching process and achieving the accurate control of the pattern and size on the substrate. Optionally, the power value of the continuously applied excitation power is unchanged, but the present application is not limited thereto.
[0067] Please continue to refer to Figure 2 Each cycle further includes: after the bias power is stopped to be applied, adjusting process parameters in a first transition time length T2 to make the process parameters meet the process requirements of the next cycle, thereby effectively improving the efficiency of atomic layer etching. Optionally, the process parameters include the flow rate of the etching gas and the pressure of the reaction chamber; preferably, during the adsorption modification process, the flow rate of the etching gas is 1-10sccm, and the pressure of the reaction chamber is 10-50mtorr; during the etching process, the flow rate of the etching gas is 100-1000sccm, and the pressure of the reaction chamber is 10-50mtorr, but the present application is not limited thereto.
[0068] Embodiment two
[0069] Please continue to refer to the accompanying drawings Figure 4As shown, the embodiment differs from the embodiment one in that, after the excitation power is applied, the excitation power has a first power value h1 within the first preset time length, and has a second power value h2 within the non-first preset time length; wherein the first power value h1 is 20% to 50% of the second power value h2, so that the required electric energy for continuously applying the excitation power can be saved, the second plasma can be maintained in the excited state to prevent the second plasma in the reaction cavity from breaking off, and the excitation power can also prevent damage to other components in the reaction cavity. Preferably, the first power value h1 is 30% of the second power value h2. Alternatively, the second power value h2 is 100 W, and the first power value h1 is 20 W to 50 W, but the present application is not limited thereto.
[0070] Embodiment three
[0071] In combination with the accompanying drawings Figures 5-6 As shown, the embodiment provides an atomic layer etching method, which comprises: a plurality of cycles performed in sequence; each cycle comprises: step S1', introducing deposition gas and etching gas into a reaction cavity; step S2', applying excitation power to ionize the deposition gas into a first plasma and ionize the etching gas into a second plasma; and the first plasma modifies a single layer or a plurality of layers of atoms on a substrate surface in the reaction cavity to form a modified layer; step S3', stopping the introduction of the deposition gas, and after a third preset time length, starting to apply a bias power to control the second plasma to etch the modified layer; and step S4', stopping the application of the bias power.
[0072] The difference between the embodiment and the embodiment one is that, in the embodiment, the third preset time length is greater than the time length required to evacuate the first plasma that has not been adsorbed after the modified layer is formed, so as to delay etching the modified layer. The second preset time length comprises a second transition time T3 and a lag time T4; the process parameters are adjusted within the second transition time T3, and the modified layer is etched within the lag time T4; and the deposition gas that has not been adsorbed after the modified layer is formed is pumped out until it is evacuated within the second transition time T3 and the lag time T4.
[0073] Specifically, the lag time T4 belongs to the etching process, equivalent to the first preset time in the first embodiment; the second transition time T3 is similar to the first transition time T2, neither belongs to the adsorption modification process nor to the etching process, that is, the adsorption modification process and the etching process are separated by the second transition time T3; and the process parameters can be adjusted in the second transition time T3 to make the process parameters meet the process requirements of the etching process, thereby effectively improving the efficiency of atomic layer etching. Alternatively, the second transition time is 1s-2s, but the present application is not limited thereto.
[0074] Specifically, with the continuous miniaturization of semiconductor devices, the process requirement for very small etching amount (such as 5nm, 3nm or 2nm process etching) can be achieved by setting the lag time T4; for example, when the modification layer is etched for 0.3s, the prior art is difficult to achieve such short duration etching because the hardware lower limit of gas flow control is above 1s (the response time of commonly used MFC (Mass Flow Controller, gas mass flow controller) on the market is usually above 1s), and the etching of 0.3s can be achieved by setting the entire etching process time to 1s and the lag time T4 in the etching process to 700ms. The setting of the lag time T4 is beneficial to precisely and independently control the etching process, thereby achieving precise control of the pattern and size on the substrate, and further meeting the process requirement for very small etching amount; by reasonably adjusting the length relationship between the second transition time T3 and the lag time T4, the cycle of a single cycle can also be effectively shortened, thereby effectively improving the efficiency of atomic layer etching. Alternatively, the lag time is 100ms-2s, but the present application is not limited thereto.
[0075] In the present embodiment, the third preset time is greater than the time required to evacuate the first plasma not adsorbed after the modification layer is formed, so the first plasma not adsorbed after the modification layer is formed can also be evacuated by the exhaust pump in the third preset time (including the second transition time T3 and the lag time T4), so that there is no first plasma in the reaction chamber when the bias power is applied, and only the second plasma or the mixture of the second plasma and the etching gas exists, to avoid the mixing of the first plasma and the second plasma when the bias power is applied, thereby avoiding the mixing of the process gas used in the adsorption modification process and the etching process in the atomic layer etching for a long time, and further avoiding the formation of mixed gas with extremely strong reactivity in the reaction chamber to cause over-etching of the substrate, meeting the requirement of atomic layer etching process for etching precision and improving the control ability of etching process.
[0076] Further, after the deposition gas is stopped, the light intensity detection device can also be used to detect the light intensity of the first plasma in the reaction chamber to accurately determine whether the first plasma is exhausted; and after the deposition gas is stopped, if the light intensity of the first plasma is less than 10% of the steady-state intensity, the first plasma not adsorbed after forming the modified layer is exhausted. More specifically, the third preset time period is not only related to the pumping rate and the volume of the reaction chamber, but also related to the process parameter adjustment rate, the lag time and other factors, and the value of the third preset time period can be set according to the specific process requirements or determined through multiple exhaustion experiments of the first plasma, but the present application is not limited thereto.
[0077] In addition, in the present embodiment, each cycle also includes the following steps: after the bias power is stopped, the process parameters are adjusted in a first transition time T2 to make the process parameters meet the process requirements of the next cycle, thereby effectively improving the efficiency of atomic layer etching.
[0078] In combination with the accompanying drawings, Figure 7 Based on the same inventive concept, the present application also provides an atomic layer etching device for implementing the atomic layer etching method as described above; the atomic layer etching device includes: a reaction chamber 110; a gas inlet device 120 arranged at the inner top of the reaction chamber 110, used to introduce deposition gas and etching gas into the reaction chamber; a susceptor 130 arranged at the inner bottom of the reaction chamber 110, used to carry a substrate 100; a first radio frequency source 140 electrically connected with the gas inlet device 120, used to output excitation power, in some other embodiments, the first radio frequency source 140 can also be electrically connected with the susceptor 130; a second radio frequency source 150 electrically connected with the susceptor 130, used to output bias power, in some other embodiments, the second radio frequency source 150 can also be electrically connected with the gas inlet device 120; a controller 160 electrically connected with the first radio frequency source 140 and the second radio frequency source 150, used to control the first radio frequency source 140 to start applying excitation power to the gas inlet device 120 and stop applying the excitation power, and also used to control the second radio frequency source 150 to start applying bias power to the susceptor 130 and stop applying the bias power.
[0079] Specifically, the controller 160 can generate a start applying excitation power instruction and a stop applying excitation power instruction and send them to the first radio frequency source 140; after receiving the start applying excitation power instruction, the first radio frequency source 140 applies the excitation power to the gas inlet device 120 to ionize the deposition gas into the first plasma, so as to modify the atoms on the surface of the substrate 100 and form the modified layer, and at the same time, the etching gas can also be ionized into the second plasma; after receiving the stop applying excitation power instruction, the first radio frequency source 140 stops applying the excitation power to the gas inlet device 120.
[0080] Specifically, the controller 160 can also generate a start applying bias power instruction and a stop applying bias power instruction and send them to the second radio frequency source 150; after receiving the start applying bias power instruction, the second radio frequency source 150 applies the bias power to the pedestal 130 to accelerate and guide the second plasma to the substrate 100, so as to perform bombardment etching on the modified layer; after receiving the stop applying bias power instruction, the second radio frequency source 150 stops applying the bias power to the pedestal 130.
[0081] Please continue to refer to Figure 7 The atomic layer etching device further comprises a light intensity detection device 170 arranged in the interior of the reaction chamber 110 and electrically connected with the controller 160, which is used for detecting the light intensity of the first plasma and sending it to the controller 160.
[0082] Specifically, in one embodiment, in the first cycle of the plurality of cycles, when the light intensity signal of the deposition gas is detected, the controller 160 generates the start applying excitation power instruction and sends it to the first radio frequency source 140; after the plurality of cycles, the controller 160 generates the stop applying excitation power instruction and sends it to the first radio frequency source 140. In another embodiment, after determining the value of the second preset time length according to multiple experiments of feeding the deposition gas, the value of the second preset time length can also be input into the controller 160; when the second preset time length is reached, the controller 160 generates the start applying excitation power instruction and sends it to the first radio frequency source 140, but the present application is not limited thereto.
[0083] Specifically, in one embodiment, after stopping feeding the deposition gas, when the light intensity of the first plasma is less than 10% of its steady-state intensity, the controller 160 generates the start applying bias power instruction and sends it to the second radio frequency source 150.
[0084] In another embodiment, the first preset time length can be input into the controller 160 after the value of the first preset time length is determined according to multiple emptying experiments of the first plasma; and the controller 160 generates the instruction of starting to apply the bias power and sends the instruction to the second RF source 150 when the first preset time length is reached.
[0085] In yet another embodiment, the third preset time length can be input into the controller 160 after the value of the third preset time length is determined according to process requirements and multiple emptying experiments of the first plasma; and the controller 160 generates the instruction of starting to apply the bias power and sends the instruction to the second RF source 150 when the third preset time length is reached.
[0086] In addition, in some embodiments, the power value of the excitation power can be adjusted by the controller 160, for example, the excitation power can be adjusted to the first power value or the second power value according to process requirements, but the present application is not limited thereto.
[0087] In summary, the atomic layer etching method and device provided by the present application can meet the requirement of etching precision of the atomic layer etching process and improve the control ability of the etching process. In the present application, the bias power can be applied after the third preset time length after the deposition gas is stopped, and the third preset time length is longer than the time length required for emptying the first plasma remaining after the modification layer is formed, so as to delay the etching step; and the third preset time length includes a second transition time length and a lag time length, the process parameters are adjusted in the second transition time length, and the modification layer is etched in the lag time length. The setting of the lag time length is beneficial to precisely and independently control the etching process, so as to precisely control the pattern and size on the substrate, and thus meet the process requirement of very small etching amount. In addition, by reasonably adjusting the length relationship between the second transition time length and the lag time length, the cycle of a single cycle can be effectively shortened, and thus the efficiency of the atomic layer etching can be effectively improved.
[0088] While the application has been described in detail by reference to preferred embodiments thereof, it is to be understood that the description is not to be construed as limiting the scope of the application. Various modifications and changes can occur to those skilled in the art, once they learn of the basic concept of the application. Therefore, the scope of the application is to be defined by the appended claims, rather than by the description of the preferred embodiments.
Claims
1. An atomic layer etching method, characterized in that, include: Multiple loops performed sequentially; Each of the aforementioned cycles includes: Deposition gas and etching gas are introduced into the reaction chamber; An excitation power is applied to ionize the deposition gas into a first plasma and the etching gas into a second plasma; and the first plasma modifies the atoms on the substrate surface within the reaction chamber to form a modified layer; The deposition gas supply is stopped, and after a first preset time, a bias power is applied to control the second plasma to etch the modified layer; and Stop applying the bias power; Wherein, the first preset duration allows at least the first plasma that was not adsorbed after the formation of the modified layer to be vented.
2. The atomic layer etching method as described in claim 1, characterized in that, In the first cycle of the plurality of cycles, the excitation power is applied after a second preset time following the introduction of the deposition gas; in the subsequent cycles of the plurality of cycles, the excitation power is continuously applied.
3. The atomic layer etching method as described in claim 1, characterized in that, After the excitation power is applied, the excitation power has a first power value within the first preset time period, and the excitation power has a second power value outside the first preset time period, wherein the first power value is 20% to 50% of the second power value.
4. The atomic layer etching method as described in claim 2, characterized in that, The second preset duration allows the deposition gas to enter the reaction chamber from the gas source via the gas pipeline.
5. The atomic layer etching method as described in claim 1, characterized in that, If the absolute value of the normalized change in the light intensity of the first plasma within a set time period does not exceed a set threshold, then the first plasma is in a steady state, and the average light intensity of the first plasma within the set time period is the steady-state intensity. After the deposition gas is stopped, if the light intensity of the first plasma is less than 10% of its steady-state intensity, the first plasma that was not adsorbed after the formation of the modified layer is vented.
6. The atomic layer etching method as described in claim 5, characterized in that, The set duration is 0s to 5s, and the set threshold is 0% to 5%.
7. The atomic layer etching method as described in claim 1, characterized in that, Each of the aforementioned cycles further includes: after stopping the application of the bias power, adjusting the process parameters within a first transition period.
8. The atomic layer etching method as described in claim 7, characterized in that, The process parameters include the flow rate of the etching gas and the pressure of the reaction chamber.
9. The atomic layer etching method as described in claim 1, characterized in that, The excitation power is higher than the bias power.
10. The atomic layer etching method as described in claim 9, characterized in that, The excitation power is high frequency, and the bias power is low frequency.
11. The atomic layer etching method as described in claim 1, characterized in that, The deposition gas is C. x H y F z Gas, C a F b Gas or C m H n A gas, wherein x, y, z, a, b, m, and n are not 0.
12. The atomic layer etching method as described in claim 11, characterized in that, The deposition gas is C. x H y F z Gas or C a F b When the etching gas is gas, the etching gas is argon or krypton; The deposition gas is C. m H n When the etching gas is gas, the etching gas includes one of argon and krypton, as well as an oxygen-containing gas.
13. An atomic layer etching method, characterized in that, include: Multiple loops performed sequentially; Each of the aforementioned cycles includes: Deposition gas and etching gas are introduced into the reaction chamber; An excitation power is applied to ionize the deposition gas into a first plasma and the etching gas into a second plasma; and the first plasma modifies the atoms on the substrate surface within the reaction chamber to form a modified layer; The deposition gas supply is stopped, and after a third preset time, a bias power is applied to control the second plasma to etch the modified layer; and Stop applying the bias power; Wherein, the third preset time is longer than the time required to purge the first plasma that was not adsorbed after the formation of the modified layer, so as to delay the etching of the modified layer; and the third preset time includes a second transition time and a hysteresis time; During the second transition period, the process parameters are adjusted, and during the lag period, the modified layer is etched. During both the second transition period and the lag period, the unadsorbed deposited gas after the formation of the modified layer is evacuated until it is vented.
14. The atomic layer etching method as described in claim 13, characterized in that, The second transition duration is 1s to 2s.
15. The atomic layer etching method as described in claim 13, characterized in that, The lag time is 100ms to 2s.
16. An atomic layer etching apparatus for implementing the atomic layer etching method as described in claim 1 or 13; characterized in that, The atomic layer etching equipment includes: reaction chamber; An air intake device is located at the top inside the reaction chamber and is used to introduce deposition gas and etching gas into the reaction chamber. A base, located at the bottom of the interior of the reaction chamber, is used to support the substrate; The first radio frequency source is used to output excitation power; The second radio frequency source is used to output bias power; The controller, electrically connected to the first RF source and the second RF source, is used to control the first RF source to start applying excitation power to the reaction cavity and to stop applying the excitation power, and is also used to control the second RF source to start applying bias power to the reaction cavity and to stop applying the bias power.
17. The atomic layer etching apparatus as described in claim 16, characterized in that, Also includes: A light intensity detection device is installed inside the reaction chamber and electrically connected to the controller. It is used to detect the light intensity of the first plasma and send it to the controller.