Control Method for Plasma Etching Process, Plasma Etching Equipment and Control Device

Abstract

The present disclosure provides a control method for a plasma etching process, a plasma etching apparatus, and a control device. The control method includes: detecting a central optical signal in a central region of a plasma etching chamber by using a central optical detection device and detecting a central optical signal in an edge region of the plasma etching chamber by using an edge optical detection device, obtaining an etching rate of the central region and an etching rate of the edge region, and when it is determined that an etching rate difference between the etching rate of the central region and the etching rate of the edge region exceeds an etching threshold range, adjusting the radio frequency power of at least one of a central coil assembly in the central region and an edge coil assembly in the edge region. This control method can monitor the etching conditions in each region. When it is found that there is a large difference in the etching rates between the central region and the edge region, the power of the central coil assembly and / or the edge coil assembly is adjusted, so that the etching rates of the central region and the edge region can be made consistent or overall balanced, thereby improving the quality of the etching process.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular, to a control method for a plasma etching process, a plasma etching apparatus, a control device, and a computer-readable storage medium. Background Art

[0002] The use of plasma to process semiconductor wafers has been widely applied in semiconductor manufacturing processes. With the reduction of semiconductor device feature sizes and the increase in process and technology complexity, there are increasingly high requirements for the control of plasma processing processes.

[0003] Taking the plasma etching process as an example, in a typical plasma etching process, different process gas combinations (such as C x F y , O2, Ar, etc.) form plasma under the action of radio frequency (RF) excitation in an RF environment. The formed plasma undergoes physical bombardment and chemical reactions with the wafer surface under the action of the electric field in the etching chamber, completing the processing of the designed pattern and key processes on the wafer surface.

[0004] However, due to the influence of power, gas, process flow, etc., there are differences in the etching rates at different locations on the semiconductor wafer. For example, the etching rates in the central region and the edge region of the semiconductor wafer differ significantly, which easily leads to problems such as etching pattern deformation, reduced performance consistency and reliability, and increased defective products. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the related art, the purpose of the present disclosure is to provide a control method for a plasma etching process, a plasma etching apparatus, a control device, and a computer-readable storage medium to solve various problems in the related art.

[0006] The first aspect of the present disclosure provides a control method for a plasma etching process, which is applied to a plasma etching apparatus. The control method for the plasma etching process includes the following steps:

[0007] A central optical detection device and an edge optical detection device are respectively arranged in the central region and the edge region at the upper part of the plasma etching chamber; wherein, a central coil assembly is provided in the central region, and an edge coil assembly is provided in the edge region;

[0008] The central optical detection device and the edge optical detection device are respectively used to detect in real time a central optical signal related to the etching rate in the central region and an edge optical signal related to the etching rate in the edge region;

[0009] Based on the central optical signal and the edge optical signal, the etching rate in the central region and the etching rate in the edge region are obtained; and

[0010] When it is determined that the etching rate difference between the etching rate of the central region and the etching rate of the edge region exceeds a preset etching threshold range, adjust the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

[0011] In some examples of the first aspect, the central optical detection device and the edge optical detection device are optical emission spectroscopy detection devices for detecting spectral information of the plasma; the spectral information of the plasma includes intensity information of the spectrum and / or change information of the spectral intensity.

[0012] In some examples of the first aspect, obtaining the etching rate of the central region and the etching rate of the edge region according to the central optical signal and the edge optical signal includes the following steps: extracting features from the spectral information of the central optical signal to identify characteristic spectral lines related to the etching rate; calculating the etching rate of the central region based on the correlation between the intensity of the characteristic spectral lines and the etching rate; extracting features from the spectral information of the edge optical signal to identify characteristic spectral lines related to the etching rate; calculating the etching rate of the edge region based on the correlation between the intensity of the characteristic spectral lines and the etching rate.

[0013] In some examples of the first aspect, in the plasma etching equipment, the central coil assembly and the edge coil assembly are connected to the radio frequency source in parallel; adjusting the radio frequency power of at least one of the central coil in the central region and the edge coil assembly in the edge region includes the following steps: adjusting the parameters of the circuit elements in the central radio frequency branch where the central coil assembly is located; and / or adjusting the parameters of the circuit elements in the edge radio frequency branch where the edge coil assembly is located.

[0014] In some examples of the first aspect, in the plasma etching equipment, the central coil assembly is connected to the central radio frequency source to form a central radio frequency circuit, and the edge coil assembly is connected to the edge radio frequency source to form an edge radio frequency circuit; adjusting the radio frequency power of at least one of the central coil in the central region and the edge coil assembly in the edge region includes the following steps: adjusting the radio frequency power of the central radio frequency source in the central radio frequency circuit; and / or adjusting the edge radio frequency power of the edge radio frequency source in the edge radio frequency circuit; or adjusting the parameters of the circuit elements related to the central coil assembly in the central radio frequency circuit; and / or adjusting the parameters of the circuit elements related to the edge coil assembly in the edge radio frequency circuit.

[0015] The second aspect of the present disclosure provides a control method for a plasma etching process, which is applied to a plasma etching device. The plasma etching device includes a plasma etching chamber. A central coil assembly and a central optical detection device are provided in the central region of the plasma etching chamber, and an edge coil assembly and an edge optical detection device are provided in the edge region of the plasma etching chamber. The control method for the plasma etching process includes the following steps:

[0016] Receive a central optical signal related to the central region detected in real time by the central optical detection device and an edge optical signal related to the edge region detected in real time by the edge optical detection device;

[0017] Obtain the etching rate of the central region and the etching rate of the edge region according to the central optical signal and the edge optical signal; and

[0018] When it is determined that the etching rate difference between the etching rate of the central region and the etching rate of the edge region exceeds a preset etching threshold range, generate a power adjustment instruction to adjust the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

[0019] In some examples of the second aspect, in the plasma etching device, the central coil assembly and the edge coil assembly are connected to a radio frequency source in parallel; the adjusting the radio frequency power of at least one of the central coil in the central region and the edge coil assembly in the edge region includes the following steps: generating a central power adjustment instruction, and adjusting the parameters of the circuit elements in the central radio frequency branch where the central coil assembly is located according to the central power adjustment instruction; and / or, generating an edge power adjustment instruction, and adjusting the parameters of the circuit elements in the edge radio frequency branch where the edge coil assembly is located according to the edge power adjustment instruction.

[0020] In some examples of the second aspect, in the plasma etching device, the central coil assembly is connected to a central radio frequency source to form a central radio frequency circuit, and the edge coil assembly is connected to an edge radio frequency source to form an edge radio frequency circuit; the adjusting the radio frequency power of at least one of the central coil in the central region and the edge coil assembly in the edge region includes the following steps: generating a central power adjustment instruction, and adjusting the radio frequency power of the central radio frequency source in the central radio frequency circuit according to the central power adjustment instruction; and / or, generating an edge power adjustment instruction, and adjusting the edge radio frequency power of the edge radio frequency source in the edge radio frequency circuit according to the edge power adjustment instruction; or, generating a central power adjustment instruction, and adjusting the parameters of the circuit elements related to the central coil assembly in the central radio frequency circuit according to the central power adjustment instruction; and / or, generating an edge power adjustment instruction, and adjusting the parameters of the circuit elements related to the edge coil assembly in the edge radio frequency circuit according to the edge power adjustment instruction.

[0021] The third aspect of the present disclosure provides a plasma etching apparatus, including:

[0022] A plasma etching chamber;

[0023] A central coil assembly and an edge coil assembly, respectively disposed in the central region and the edge region of the upper part of the plasma etching chamber;

[0024] A central optical detection device and an edge optical detection device, respectively configured in the central region and the edge region;

[0025] A control device, communicatively connected to the central coil assembly, the edge coil assembly, the central optical detection device, and the edge optical detection, for obtaining the etching rate of the central region and the etching rate of the edge region according to the central optical signal detected in real time from the central optical detection device and the edge optical signal detected in real time from the edge optical detection device, and generating a power adjustment instruction when determining that the etching rate difference between the etching rate of the central region and the etching rate of the edge region exceeds a preset etching threshold range, and adjusting the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

[0026] The fourth aspect of the present disclosure provides a control device, including: a processor; a memory storing a control program for a plasma etching process; wherein, when the control program for the plasma etching process is run by the processor, it executes the control method for the plasma etching process as described above.

[0027] The fifth aspect of the present disclosure provides a computer-readable storage medium, on which a control program for a plasma etching process is stored, and when the control program for the plasma etching process is run by the processor, it executes the control method for the plasma etching process as described above.

[0028] As described above, embodiments of the present disclosure provide a control method for a plasma etching process, a plasma etching apparatus, a control device, and a computer-readable storage medium. In the control method for the plasma etching process, a central optical detection device is used to detect a central optical signal in a central region of a plasma etching chamber, and an edge optical detection device is used to detect a central optical signal in an edge region of the plasma etching chamber. Accordingly, an etching rate in the central region and an etching rate in the edge region are obtained. When it is determined that an etching rate difference between the etching rate in the central region and the etching rate in the edge region exceeds a preset etching threshold range, the radio frequency power of at least one of the central region and the edge region is adjusted. Compared with the related art, the control method for the plasma etching process provided by the present disclosure can comprehensively monitor the etching in each region of the plasma etching chamber, and when it is found that the etching rates in the middle region and the edge region are quite different, the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region is adjusted so that the etching rates in the central region and the edge region can reach consistency or overall balance, which can ensure the normal operation of related processes and provide the quality of the etching process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It shows a schematic structural diagram of the plasma etching apparatus of the present disclosure in an embodiment.

[0030] Figure 2 It shows a schematic principle diagram of the plasma etching apparatus of the present disclosure in an embodiment.

[0031] Figure 3 It shows a schematic circuit diagram in which a central coil assembly and an edge coil assembly are connected to a radio frequency source in a parallel manner.

[0032] Figure 4 It shows Figure 3 the equivalent circuit schematic diagram of

[0033] Figure 5 It shows a schematic flow chart of the control method for the plasma etching process provided by the present disclosure in an embodiment.

[0034] Figure 6 It shows Figure 5 the refined flow chart in an embodiment.

[0035] Figure 7 It shows a schematic flow chart of the control method for the plasma etching process provided by the present disclosure in another embodiment.

[0036] Figure 8 It shows a schematic block diagram of the control device provided by the present disclosure in an embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The following specific examples illustrate the embodiments of the present disclosure. Those skilled in the art can easily understand other advantages and effects of the present disclosure from the information disclosed in the present disclosure. The present disclosure can also be implemented or applied through other different specific embodiments. The details in the present disclosure can also be modified or changed according to different viewpoints and application modules without departing from the spirit of the present disclosure. It should be noted that, without conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0038] The following takes the accompanying drawings as a reference and details the embodiments of the present disclosure so that those skilled in the art to which the present disclosure pertains can easily implement it. The present disclosure can be embodied in many different forms and is not limited to the embodiments described herein.

[0039] In the description of the present disclosure, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc., mean that the specific features, structures, materials, or characteristics represented by the embodiment or example are included in at least one embodiment or example of the present disclosure. Moreover, the specific features, structures, materials, or characteristics represented can be combined in a suitable manner in any one or a group of embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples represented in the present disclosure and the features of the different embodiments or examples.

[0040] In addition, the terms "first" and "second" are only used for the purpose of indication and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "a group" is two or more unless otherwise specifically defined.

[0041] To clearly illustrate the present disclosure, devices irrelevant to the description are omitted, and the same or similar components throughout the specification are given the same reference numerals.

[0042] Throughout the specification, when it is said that a device is "connected" to another device, this includes not only the case of "direct connection", but also the case of "indirect connection" with other elements placed therebetween. In addition, when it is said that a certain device "includes" a certain component, unless there is a particularly contrary record, it does not exclude other components, but means that other components can also be included.

[0043] Although in some examples the terms first, second, etc. are used herein to denote various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first interface and a second interface, etc. are indicated. Further, as used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms unless the context indicates otherwise. It should be further understood that the terms "comprising", "including" indicate the presence of the stated features, steps, operations, elements, modules, items, kinds, and / or groups, but do not preclude the presence, occurrence, or addition of one or a group of other features, steps, operations, elements, modules, items, kinds, and / or groups. The terms "or" and "and / or" used herein are to be construed as inclusive, or meaning any one or any combination. Thus, "A, B, or C" or "A, B, and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A, B, and C". An exception to this definition only occurs when the combination of elements, functions, steps, or operations are mutually exclusive in some way.

[0044] The technical terms used herein are only for referring to specific embodiments and are not intended to limit the present disclosure. The singular forms used herein also include the plural forms as long as the statements do not clearly indicate the opposite meaning there. The meaning of "including" used in the specification is to embody specific characteristics, regions, integers, steps, operations, elements, and / or components, and does not exclude the existence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0045] Although not defined differently, including the technical terms and scientific terms used herein, all terms have the same meaning as generally understood by those skilled in the technical field to which the present disclosure belongs. Terms defined in commonly used dictionaries are additionally interpreted to have a meaning consistent with the relevant technical literature and the currently presented information, and should not be over-interpreted as ideal or very formulaic meanings as long as they are not defined.

[0046] In a plasma processing process involving semiconductor wafers, there are strict requirements for the uniformity of the etching rate in the process chamber to ensure the product quality and yield of the semiconductor wafer during the process implementation.

[0047] Embodiments of the present disclosure provide a control method and a plasma etching device for a plasma etching process, which are used to simultaneously monitor the etching rates of the central region and the edge region in a plasma etching chamber, and when it is determined that the etching rate difference between the two etching rates exceeds a preset etching threshold range, adjust the radio frequency power of at least one of the central region and the edge region so that the etching rates of the central region and the edge region can reach consistency or overall balance.

[0048] The plasma etching equipment in this embodiment may include: a plasma etching chamber, a central coil assembly, an edge coil assembly, a central optical detection device, an edge optical detection device, and a control device.

[0049] See also Figure 1 and Figure 2 ,in, Figure 1 It is a schematic diagram showing the structure of the plasma etching device in one embodiment of the present disclosure. Figure 2 FIG. 1 is a schematic diagram showing the principle of a plasma etching device according to an embodiment of the present disclosure.

[0050] The plasma etching chamber 10 is suitable for being a chamber for performing process processing on semiconductor wafers.

[0051] The plasma etching chamber 10 comprises a sealed chamber with sidewalls, and a wafer carrying platform 11 is provided at the center of the sealed chamber.

[0052] The process chamber is connected to a multi-way gas inlet device for supplying the required reaction gases to the plasma etching chamber 10. In some embodiments, the top of the process chamber is connected to the multi-way gas inlet device. In some embodiments, the side of the process chamber is connected to the multi-way gas inlet device. In some embodiments, the top and side of the process chamber are connected to the multi-way gas inlet device.

[0053] The process chamber is connected to an exhaust device for extracting the reaction gas in the plasma etching chamber. In some embodiments, the exhaust device may include an exhaust pipeline connected to the plasma etching chamber 10 and an exhaust valve assembly and an exhaust pump provided on the exhaust pipeline.

[0054] In certain embodiments, the exhaust valve assembly includes an exhaust valve.

[0055] In certain embodiments, the exhaust valve assembly includes a combination of an exhaust valve and a throttle valve. For example, the exhaust valve may be a conventional exhaust valve. For example, the exhaust valve may be a combination of a fast exhaust valve and a slow exhaust valve, wherein the slow exhaust valve is used to establish an initial vacuum environment, and the fast exhaust valve is used to more quickly exhaust residual gas to achieve a lower vacuum level. The throttle valve may be, for example, a butterfly valve capable of achieving an opening and closing degree of 0% to 100%.

[0056] The plasma etching chamber 10 may have an inlet and outlet opening on its sidewall. This opening facilitates the transfer of workpieces, including but not limited to wafers. Typically, a first slit door is provided at the inlet and outlet opening, which can move vertically or horizontally relative to the inlet and outlet opening.

[0057] The wafer carrier 11 is disposed within the plasma etching chamber 10 for carrying the semiconductor wafer 100, which may be, for example, a wafer. In certain embodiments, a thin film deposition process is performed on only one semiconductor wafer 100 at a time within the plasma etching chamber 10. Accordingly, the wafer carrier 11 is located at the central position of the plasma etching chamber 10.

[0058] In certain embodiments, the wafer carrier 11 further includes an adsorption structure for adsorbing the semiconductor wafer 100. Exemplarily, the adsorption structure may include, for example, an adsorption groove and an adsorption pump.

[0059] In certain embodiments, a heating device (not shown in the figures) may be disposed below the wafer carrier 11 for heating the carried semiconductor wafer 100 to a desired temperature. In certain embodiments, the sidewall surface and the top cover surface of the plasma etching chamber 10 may be coated with a high-reflection film or surface polished to reflect the thermal radiation heated by the heating device back to the surface of the wafer carrier 11 and the semiconductor wafer 100 carried thereon.

[0060] In certain embodiments, the wafer carrier 11 may be associated with a moving member. By using the moving member, the wafer carrier 11 can be driven to move. Exemplarily, the moving member may be, for example, a lifting member, which can drive the wafer carrier 11 and the semiconductor wafer 100 carried thereon to perform a lifting movement.

[0061] In certain embodiments, the wafer carrier 11 may be associated with a rotating device. The rotating device may include a selected rotating member and a rotating power mechanism. The rotating member may be hermetically disposed with the wafer carrier 11 and the plasma etching chamber 10. The selected power mechanism can drive the rotating member and the associated wafer carrier 11 and the semiconductor wafer 100 carried thereon to perform a reciprocating rotation, enabling the plasma treatment process of the semiconductor wafer 100 to be more uniform.

[0062] A device for providing radio frequency excitation is configured within the plasma etching chamber 10.

[0063] In the plasma etching process, different process gas combinations (e.g., fluorocarbons, oxygen, argon, etc.) form a plasma under the action of radio frequency excitation in a radio frequency environment. The plasma physically bombards and chemically reacts with the surface of the semiconductor wafer within the plasma etching chamber to obtain the desired etching pattern or deposition layer. Typical plasma etching chambers include two types: Capacitive Coupled Plasma (CCP) and Inductive Coupled Plasma (ICP).

[0064] The generation of capacitively coupled plasma (CCP) is achieved by applying a radio frequency (RF) power source to two electrode plates of a parallel plate capacitor, forming a high-frequency electric field. Initial electrons in the gas within the plasma etching cavity gain energy under the action of the high-frequency electric field, bombarding gas molecules to generate more electrons, ions, and radical particles, thus forming a dynamically balanced low-temperature plasma.

[0065] The generation of inductively coupled plasma (ICP) is accomplished by applying an RF current to an induction coil, which induces a high-frequency oscillating magnetic field within the plasma etching cavity. The rapidly changing induced magnetic field generates an induced electric field within the plasma etching cavity, enabling initial electrons in the gas to acquire energy, thereby bombarding particles within the plasma etching cavity to generate low-temperature plasma.

[0066] In the embodiment as Figure 1 shown, the plasma etching cavity 10 employs inductively coupled plasma (ICP).

[0067] The wafer carrier 11 can serve as the lower electrode and is connected to at least one RF bias source (not shown in the figure). According to the requirements of the etching process, the RF frequency of the RF bias source can be high frequency, medium frequency, or low frequency. For example, the high frequency can be an RF bias source of 13.56 MHz; the medium frequency can be an RF bias source of 2 MHz, and the low frequency can be an RF bias source of several kilohertz. The wafer carrier 11 can be made of a metal plate.

[0068] Correspondingly, above the plasma etching cavity 10, there is a coil assembly opposite to the wafer carrier 11 serving as the lower electrode.

[0069] In the central region of the upper part of the plasma etching cavity 10, a central coil assembly 121 is provided, and in the edge region of the upper part of the plasma etching cavity 10, an edge coil assembly 123 is provided. The central coil assembly 121 is used to provide RF power for the central region, and the edge coil assembly 123 is used to provide RF power for the edge region.

[0070] In some embodiments, the central coil assembly 121 includes a central coil body, which adopts a multi-turn coil in a spiral shape, and the multi-turn coils are concentrically arranged. Exemplarily, a bell jar 14 is provided in the central region of the plasma etching cavity 10. The bell jar 14 can have a conical structure, and the multi-turn coil is sleeved on the bell jar 14 in a spiral manner. In practical applications, the bell jar 14 can be made of ceramic material. In addition, the central coil assembly further includes an input end and an output end. The input end and the output 1 end are respectively connected to both ends of the central coil body. Among them, the input end can be used to electrically connect to the central RF source, and the output end can be used to ground.

[0071] In some embodiments, the edge coil assembly 123 includes an edge coil body, and the edge coil body adopts a multi-turn coil in a spiral shape, and the multi-turn coils are concentrically arranged. Exemplarily, in the edge region of the plasma etching chamber 10, a mounting plate structure 143 connected to the bell jar 14 is provided, and the multi-turn coils are laid on the mounting plate structure 143 in a spiral manner. In practical applications, the mounting plate structure 143 can be made of ceramic material. In addition, the edge coil assembly further includes an input end and an output end, and the input end and the output end are respectively connected to two ends of the edge coil body, wherein the input end can be used for electrical connection with an edge radio frequency source, and the output end can be used for grounding.

[0072] Corresponding to the central coil assembly and the edge coil assembly, a central optical detection device 131 is provided in the central region of the upper part of the plasma etching chamber 10 and an edge optical detection device 133 is provided in the edge region, wherein the central optical detection device 131 is used for detecting in real time a central optical signal related to the etching rate in the central region, and the edge optical detection device 133 is used for detecting in real time an edge optical signal related to the etching rate in the edge region.

[0073] In some embodiments, the central optical detection device and the edge optical detection device are optical emission spectroscopy detection devices for detecting spectral information of the plasma; the spectral information of the plasma includes intensity information of the spectrum and / or variation information of the spectral intensity.

[0074] Exemplarily, in practical applications, the spectral information of the central optical signal is extracted by using the central optical detection device to identify characteristic spectral lines related to the etching rate; based on the correlation between the intensity of the characteristic spectral lines and the etching rate, the etching rate of the central region is calculated. The spectral information of the edge optical signal is extracted by using the edge optical detection device to identify characteristic spectral lines related to the etching rate; based on the correlation between the intensity of the characteristic spectral lines and the etching rate, the etching rate of the edge region is calculated.

[0075] In some embodiments, the central optical detection device 131 may employ an Optical Emission Spectrometer (OES), and the edge optical detection device 133 may also employ an OES. For the OES, its working principle may include: an external light source provides incident light, and the reflected light is received by the OES. The change state of the film thickness is detected by analyzing the spectrometer signal. The working principle is as follows: the incident light SE undergoes a first reflection on the upper surface of the etched film layer to form a first-order reflected light SR1 and a transmitted light ST. The transmitted light ST continues to propagate and undergoes a second reflection at the interface between the etched film layer and the substrate to form a second-order reflected light SR2. The second-order reflected light SR2 undergoes transmission at the upper surface of the etched film layer and forms an interference signal SI with the first-order reflected light at this position. The first-order reflected light SR1 and the second-order reflected light SR2 are homologous lights with the same frequency and a strong interference signal. This interference signal SI exhibits an obvious periodicity, which is related to the optical path difference between the first-order reflected light SR1 and the second-order reflected light SR2. The optical path difference refers to the optical path difference between two light beams arriving at the same point through different paths. Here, the optical path difference is twice the thickness of the etched film. When the two light beams arrive at the same point, if their phases are the same, they will reinforce each other to produce bright fringes; if the phases are opposite, they will cancel each other out to produce dark fringes. If the optical path difference between the two light beams is an integer multiple of the wavelength, their phases are the same, and they will reinforce each other to produce bright fringes; if the optical path difference is an odd multiple of half the wavelength, the phases are opposite, and they will cancel each other out to produce dark fringes. Therefore, the position and shape of the interference bright and dark fringes depend on the optical path difference of the light beams. If the optical path difference between the two light beams is an integer multiple of the wavelength, an equal number of bright fringes and dark fringes will be produced. If the optical path difference, i.e., the film thickness, changes, the position and number of the fringes will also change accordingly. By observing the real-time change in light intensity, the degree of change in the film thickness can be grasped.

[0076] In practical applications, the number of central optical detection devices 131 may be one or more, and the number of edge optical detection devices 133 may be multiple. The multiple edge optical detection devices 133 are evenly distributed in the edge area.

[0077] The control device 15 is communicatively connected to the central coil assembly, the edge coil assembly, the central optical detection device, and the edge optical detection. In some embodiments, the control device may be, for example, a host computer.

[0078] The control device 15 is configured to obtain the etching rate of the central region and the etching rate of the edge region based on the central optical signal detected in real time from the central optical detection device 131 and the edge optical signal detected in real time from the edge optical detection device 133.

[0079] In addition, when it is determined that the etching rate difference between the etching rate of the central region and the etching rate of the edge region exceeds a preset etching threshold range, the control device 15 is further configured to generate a power adjustment instruction to adjust the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

[0080] In some embodiments, the etching rate difference between the etching rate of the central region and the etching rate of the edge region is the absolute difference in etching rate, and the preset etching threshold range is the absolute etching difference threshold range. That is, the control device 15 directly subtracts the obtained etching rate of the central region from the etching rate of the edge region to obtain the absolute etching rate difference between the two, and compares the absolute etching rate difference with the preset absolute etching difference threshold range. If the comparison result shows that the absolute etching rate difference is within the preset absolute etching difference threshold range, it indicates that the etching rate difference between the two is small and no adjustment is required; if the comparison result shows that the absolute etching rate difference exceeds the preset absolute etching difference threshold range, it indicates that the etching rate difference between the two is large, and a power adjustment instruction is generated to adjust the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

[0081] Exemplarily, the etching threshold range can be set to [-a, +a], where a is an etching rate value.

[0082] Exemplarily, the etching threshold range can be set to [-a, +b], where a and b are different etching rate values.

[0083] For example, the absolute etching rate difference obtained by directly subtracting the etching rate of the central region from the etching rate of the edge region is compared with the preset absolute etching difference threshold range. The comparison result shows that the absolute etching rate difference exceeds the lower limit of the absolute etching difference threshold range, indicating that the etching rate of the central region is less than the etching rate of the edge region and the etching rate difference between the two is large. A power adjustment instruction is generated, either increasing the radio frequency power of the central coil assembly in the central region, or decreasing the radio frequency power of the edge coil assembly in the edge region, or increasing the radio frequency power of the central coil assembly in the central region and decreasing the radio frequency power of the edge coil assembly in the edge region simultaneously.

[0084] For example, the absolute difference in etching rates between the central region and the edge region is directly calculated and compared with a preset threshold range of the absolute etching difference. If the comparison result shows that the absolute etching difference exceeds the upper limit of the preset threshold range of the absolute etching difference, it indicates that the etching rate of the central region is greater than that of the edge region and the difference in their etching rates is significant. A power adjustment instruction is generated, either reducing the RF power of the central coil assembly in the central region, or increasing the RF power of the edge coil assembly in the edge region, or simultaneously reducing the RF power of the central coil assembly in the central region and increasing the RF power of the edge coil assembly in the edge region.

[0085] In some embodiments, the etching rate difference between the etching rate of the central region and the etching rate of the edge region is the etching rate deviation, and the preset etching threshold range is the etching deviation threshold range. The etching rate deviation is the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region, or the etching rate deviation is the ratio of the difference between the etching rate of the edge region and the etching rate of the central region to the etching rate of the central region. That is, the control device 15 calculates the etching rate deviation between the obtained etching rate of the central region and the etching rate of the edge region, and compares the etching rate deviation with the preset etching deviation threshold range. If the comparison result shows that the etching rate deviation is within the preset etching deviation threshold range, it indicates that the difference in their etching rates is small and no adjustment is required; if the comparison result shows that the etching rate deviation exceeds the preset etching deviation threshold range, it indicates that the difference in their etching rates is significant, and a power adjustment instruction is generated to adjust the RF power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

[0086] Exemplarily, the etching deviation threshold range can be set to [-a%, +a%]. For example, the etching deviation threshold range is [-3%, +3%], or [-1%, +1%], [-2%, +2%], [-4%, +4%], [-5%, +5%], etc.

[0087] Exemplarily, the etching deviation threshold range can be set to [-a%, +b%], where a and b are different numbers. For example, the etching deviation threshold range is [-1%, +2%], or [-2%, +3%], [-2%, +1%], [-3%, +2%], etc.

[0088] For example, the etching rate deviation between the central region and the edge region is obtained by calculating the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region. The etching rate deviation is compared with a preset etching deviation threshold range. If the comparison result shows that the etching rate deviation exceeds the lower limit of the etching deviation threshold range, it indicates that the etching rate of the central region is less than that of the edge region and the difference in etching rates between the two is large. A power adjustment command is generated, either increasing the RF power of the central coil assembly in the central region, or decreasing the RF power of the edge coil assembly in the edge region, or simultaneously increasing the RF power of the central coil assembly in the central region and decreasing the RF power of the edge coil assembly in the edge region.

[0089] For example, the etching rate deviation between the central region and the edge region is obtained by calculating the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region. The etching rate deviation is compared with a preset etching deviation threshold range. If the comparison result shows that the etching rate deviation exceeds the upper limit of the etching deviation threshold range, it indicates that the etching rate of the central region is greater than that of the edge region and the difference in etching rates between the two is large. A power adjustment command is generated, either decreasing the RF power of the central coil assembly in the central region, or increasing the RF power of the edge coil assembly in the edge region, or simultaneously decreasing the RF power of the central coil assembly in the central region and increasing the RF power of the edge coil assembly in the edge region.

[0090] In some embodiments, in the plasma etching equipment, the central coil assembly and the edge coil assembly are connected to the RF source in parallel.

[0091] Please refer to Figure 3 , which shows a schematic circuit diagram of the central coil assembly and the edge coil assembly connected to the RF source in parallel.

[0092] As Figure 3 shown, in the circuit, there are an RF source S, a matcher, and a parallel central RF branch and edge RF branch. In the central RF branch, there are a central coil assembly 121 and other related circuit elements, and the circuit elements include but are not limited to a tunable capacitor C S1 , an inductor L1, etc. In the edge RF branch, there are an edge coil assembly 123 and other related circuit elements, and the circuit elements include but are not limited to a tunable capacitor C S2 , an inductor L2, etc. For ease of description, the parallel central RF branch and edge RF branch can be collectively referred to as the cavity circuit.

[0093] Please refer to Figure 4 , which shows Figure 3 the equivalent circuit diagram.

[0094] Combined withFigure 3 and Figure 4 perform an analysis on the above circuit.

[0095] In the central RF branch:

[0096] For the central coil assembly, , where represents the impedance of the central coil assembly, represents the resistance of the central coil assembly, represents the inductive reactance of the central coil assembly.

[0097] For the central RF branch:

[0098]

[0099] where represents the impedance of the central RF branch, represents the impedance of the central coil assembly, represents the inductive reactance of the inductor in the central RF branch, represents the capacitive reactance of the adjustable capacitor in the central RF branch.

[0100] As can be seen from the above, by adjusting the capacitance value of the adjustable capacitor C S1 , the impedance of the central RF branch can be changed.

[0101] In the peripheral RF branch:

[0102] For the peripheral coil assembly, , where represents the impedance of the central coil assembly, represents the resistance of the central coil assembly, represents the inductive reactance of the central coil assembly.

[0103] For the central RF branch:

[0104]

[0105] where represents the impedance of the peripheral RF branch, represents the impedance of the peripheral coil assembly, represents the inductive reactance of the inductor L2 in the peripheral RF branch, represents the capacitive reactance of the adjustable capacitor C S2 in the peripheral RF branch.

[0106] As can be seen from the above, by adjusting the capacitance value of the adjustable capacitor C S2 , the impedance of the peripheral RF branch can be changed.

[0107] InFigure 4 In the equivalent circuit, R1 represents the sum of the internal resistance of the radio frequency source and the resistance of the matcher, Z1 represents the impedance of the central radio frequency branch, Z2 represents the impedance of the edge radio frequency branch, and P1 represents the output power of the radio frequency source.

[0108] Total resistance in the cavity circuit:

[0109] Total voltage of the equivalent circuit:

[0110] Total current of the equivalent circuit:

[0111] Cavity voltage: , where V1 represents the voltage of the central radio frequency branch and V2 represents the voltage of the edge radio frequency branch.

[0112] Current of the central radio frequency branch: , power of the central radio frequency branch: ;

[0113] Current of the edge radio frequency branch: , power of the edge radio frequency branch: .

[0114] As can be seen from the above, the power distributed to the central radio frequency branch and the edge radio frequency branch can be realized by changing the values of the adjustable capacitors C S1 、C S2 , thereby affecting the etching rate of the corresponding central region and the etching rate of the corresponding edge region.

[0115] Of course, in the above-mentioned central radio frequency branch and edge radio frequency branch, it is not limited to adjustable capacitors. In some embodiments, the central radio frequency branch and the edge radio frequency branch may include adjustable inductors or adjustable resistors. By changing the adjustable inductors or adjustable resistors, the power distributed to the central radio frequency branch and the edge radio frequency branch can also be changed, thereby affecting the etching rate of the corresponding central region and the etching rate of the corresponding edge region.

[0116] In some embodiments, in the plasma etching equipment, the central coil assembly is connected to the central radio frequency source to form a central radio frequency circuit, and the edge coil assembly is connected to the edge radio frequency source to form an edge radio frequency circuit.

[0117] The central radio frequency circuit formed by connecting the central coil assembly to the central radio frequency source is independent of the edge radio frequency circuit formed by connecting the edge coil assembly to the edge radio frequency source.

[0118] In some cases, the RF power of at least one of the central coil in the central region and the edge coil assembly in the edge region can be adjusted by adjusting the RF power of the central RF source in the central RF circuit and / or adjusting the edge RF power of the edge RF source in the edge RF circuit.

[0119] Changing the power on the central RF circuit by adjusting the RF power of the central RF source in the central RF circuit affects the etching rate of the corresponding central region. Exemplarily, increasing the RF power of the central RF source in the central RF circuit increases the power on the central RF circuit and increases the etching rate of the corresponding central region. Exemplarily, decreasing the RF power of the central RF source in the central RF circuit decreases the power on the central RF circuit and decreases the etching rate of the corresponding central region.

[0120] Changing the power on the edge RF circuit by adjusting the RF power of the edge RF source in the edge RF circuit affects the etching rate of the corresponding edge region. Exemplarily, increasing the RF power of the edge RF source in the edge RF circuit increases the power on the edge RF circuit and increases the etching rate of the corresponding edge region. Exemplarily, decreasing the RF power of the edge RF source in the edge RF circuit decreases the power on the edge RF circuit and decreases the etching rate of the corresponding edge region.

[0121] In some cases, the RF power of at least one of the central coil in the central region and the edge coil assembly in the edge region can be adjusted by adjusting the parameters of the circuit elements related to the central coil assembly in the central RF circuit and / or adjusting the parameters of the circuit elements related to the edge coil assembly in the edge RF circuit.

[0122] As mentioned above, exemplarily, the central RF circuit includes a tunable capacitor, and the RF power in the central RF circuit is changed by adjusting the tunable capacitor, affecting the etching power of the corresponding central region.

[0123] As mentioned above, exemplarily, the edge RF circuit includes a tunable capacitor, and the RF power in the edge RF circuit is changed by adjusting the tunable capacitor, affecting the etching power of the corresponding edge region.

[0124] Embodiments of the present disclosure provide a plasma etching device. A central coil assembly and an edge coil assembly are respectively arranged in the central area and the edge area of the upper part of the plasma etching cavity. Correspondingly, a central optical detection device and an edge optical detection device are respectively arranged in the central area and the edge area. The control device is communicatively connected to the central coil assembly, the edge coil assembly, the central optical detection device, and the edge optical detection device. The central optical detection device is used to detect the central optical signal in the central area of the plasma etching cavity, and the edge optical detection device is used to detect the central optical signal in the edge area of the plasma etching cavity. The control device receives the central optical signal detected in real time by the central optical detection device and the edge optical signal detected in real time by the edge optical detection device, and thereby obtains the etching rate of the central area and the etching rate of the edge area. When it is determined that the etching rate difference between the etching rate of the central area and the etching rate of the edge area exceeds a preset etching threshold range, the radio frequency source device is controlled to adjust the radio frequency power of at least one of the central area and the edge area. Compared with the related art, the plasma etching device provided by the present disclosure can comprehensively monitor the etching of each area in the plasma etching cavity. When it is found that the etching rates of the middle area and the edge area differ greatly, the radio frequency power of at least one of the central coil assembly in the central area and the edge coil assembly in the edge area is adjusted, so that the etching rates of the central area and the edge area can reach consistency or overall balance, which can ensure the normal operation of related processes and provide the quality of the etching process.

[0125] Please refer to Figure 5 , which shows a schematic flow chart of the control method of the plasma etching process provided by the present disclosure in an embodiment.

[0126] Step S501: A central optical detection device and an edge optical detection device are respectively arranged in the central area and the edge area of the upper part of the plasma etching cavity.

[0127] As Figure 1 shown, a central optical detection device 131 is arranged in the central area of the upper part of the plasma etching cavity 10, and an edge optical detection device 133 is arranged in the edge area. Among them, the central optical detection device 131 is used to detect in real time the central optical signal related to the etching rate in the central area, and the edge optical detection device 133 is used to detect in real time the edge optical signal related to the etching rate in the edge area.

[0128] Step S503: The central optical detection device and the edge optical detection device are respectively used to detect in real time the central optical signal related to the etching rate in the central area and the edge optical signal related to the etching rate in the edge area.

[0129] In some embodiments, the central optical detection device and the edge optical detection device are optical emission spectroscopy detection devices. The spectral information of the plasma can be detected by the optical emission spectroscopy detection device. Among them, the spectral information of the plasma includes the intensity information of the spectrum and / or the change information of the spectral intensity.

[0130] Step S505: Obtain the etching rate of the central region and the etching rate of the edge region according to the central optical signal and the edge optical signal.

[0131] In step S505, the obtaining the etching rate of the central region and the etching rate of the edge region according to the central optical signal and the edge optical signal includes: extracting features from the spectral information of the central optical signal to identify the characteristic spectral lines related to the etching rate; calculating the etching rate of the central region based on the correlation between the intensity of the characteristic spectral lines and the etching rate; extracting features from the spectral information of the edge optical signal to identify the characteristic spectral lines related to the etching rate; calculating the etching rate of the edge region based on the correlation between the intensity of the characteristic spectral lines and the etching rate.

[0132] Step S507: When it is determined that the etching rate difference between the etching rate of the central region and the etching rate of the edge region exceeds the preset etching threshold range, adjust the RF power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

[0133] For step S507, reference can be made to Figure 6 which is shown as Figure 5 the detailed flowchart in an embodiment.

[0134] As Figure 6 shown, step S5071: Calculate the etching rate difference between the etching rate of the central region and the etching rate of the edge region according to the etching rate of the central region and the etching rate of the edge region.

[0135] In some embodiments, the etching rate difference between the etching rate of the central region and the etching rate of the edge region is the absolute difference of the etching rates, that is, the absolute difference of the etching rates of the two is directly obtained by subtracting the etching rate of the edge region from the etching rate of the central region.

[0136] In some embodiments, the etching rate difference between the etching rate of the central region and the etching rate of the edge region is the etching rate deviation, that is, the etching rate deviation is the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region, or the etching rate deviation is the ratio of the difference between the etching rate of the edge region and the etching rate of the central region to the etching rate of the central region.

[0137] Step S5073: Compare the etching rate difference with a preset etching threshold range to determine whether the etching rate difference is within the etching threshold range.

[0138] In step S5073, compare the etching rate difference calculated in step S5071 with a preset etching threshold range. If the etching rate difference exceeds the etching threshold range, proceed to step S5075; if the etching rate difference is within the etching threshold range, it indicates that the etching rate of the central region is basically the same as that of the edge region.

[0139] In some embodiments, the etching rate difference between the etching rate of the central region and that of the edge region is the absolute difference in etching rate, and the preset etching threshold range is the absolute difference threshold range of etching rate. Compare the absolute difference in etching rate with the preset absolute difference threshold range of etching rate.

[0140] In some embodiments, the etching rate difference between the etching rate of the central region and that of the edge region is the etching rate deviation, and the preset etching threshold range is the etching deviation threshold range. The etching rate deviation is the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region, or the etching rate deviation is the ratio of the difference between the etching rate of the edge region and the etching rate of the central region to the etching rate of the central region. That is, calculate the etching rate deviation between the etching rate of the central region and the etching rate of the edge region, and compare the etching rate deviation with the preset etching deviation threshold range.

[0141] Step S5075: Adjust the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

[0142] In some embodiments, the etching rate difference between the etching rate of the central region and that of the edge region is the absolute difference in etching rate, and the preset etching threshold range is the absolute difference threshold range of etching rate.

[0143] For example, directly subtract the etching rate of the central region from the etching rate of the edge region to obtain the absolute difference in etching rate between the two, and compare it with the preset absolute difference threshold range of etching rate. The comparison result shows that the absolute difference in etching rate exceeds the lower limit of the absolute difference threshold range of etching rate, indicating that the etching rate of the central region is less than that of the edge region and the etching rate gap between the two is large. Either increase the radio frequency power of the central coil assembly in the central region, or decrease the radio frequency power of the edge coil assembly in the edge region, or increase the radio frequency power of the central coil assembly in the central region and decrease the radio frequency power of the edge coil assembly in the edge region simultaneously.

[0144] For example, the absolute difference in the etching rates between the central region and the edge region is directly calculated and compared with a preset threshold range of the absolute etching difference. If the comparison result shows that the absolute difference in the etching rates exceeds the upper limit of the threshold range of the absolute etching difference, it indicates that the etching rate of the central region is greater than that of the edge region and the difference in their etching rates is relatively large. In this case, either the RF power of the central coil assembly in the central region is reduced, or the RF power of the edge coil assembly in the edge region is increased, or both the RF power of the central coil assembly in the central region is reduced and the RF power of the edge coil assembly in the edge region is increased.

[0145] In some embodiments, the difference in the etching rates between the central region and the edge region is the etching rate deviation, the preset threshold range is the threshold range of the etching deviation, and the etching rate deviation is the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region, or the etching rate deviation is the ratio of the difference between the etching rate of the edge region and the etching rate of the central region to the etching rate of the central region.

[0146] For example, the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region is calculated to obtain the etching rate deviation between the two. The etching rate deviation is compared with a preset threshold range of the etching deviation. If the comparison result shows that the etching rate deviation is below the lower limit of the threshold range of the etching deviation, it indicates that the etching rate of the central region is less than that of the edge region and the difference in their etching rates is relatively large. In this case, either the RF power of the central coil assembly in the central region is increased, or the RF power of the edge coil assembly in the edge region is reduced, or both the RF power of the central coil assembly in the central region is increased and the RF power of the edge coil assembly in the edge region is reduced.

[0147] For example, the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region is calculated to obtain the etching rate deviation between the two. The etching rate deviation is compared with a preset threshold range of the etching deviation. If the comparison result shows that the etching rate deviation exceeds the upper limit of the threshold range of the etching deviation, it indicates that the etching rate of the central region is greater than that of the edge region and the difference in their etching rates is relatively large. In this case, either the RF power of the central coil assembly in the central region is reduced, or the RF power of the edge coil assembly in the edge region is increased, or both the RF power of the central coil assembly in the central region is reduced and the RF power of the edge coil assembly in the edge region is increased.

[0148] In some embodiments, in the plasma etching equipment, the central coil assembly and the edge coil assembly are connected to the radio frequency source in parallel. Therefore, in step S5075, adjusting the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region may specifically include: adjusting the parameters of the circuit elements in the central radio frequency branch where the central coil assembly is located; and / or, adjusting the parameters of the circuit elements in the edge radio frequency branch where the edge coil assembly is located. The circuit elements may be, for example, adjustable capacitors, or adjustable inductors, or adjustable resistors, etc.

[0149] In some embodiments, in the plasma etching equipment, the central coil assembly is connected to a central radio frequency source to form a central radio frequency circuit, and the edge coil assembly is connected to an edge radio frequency source to form an edge radio frequency circuit. The central radio frequency circuit and the edge radio frequency circuit are independent of each other. Therefore, in step S5075, adjusting the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region may specifically include: adjusting the radio frequency power of the central radio frequency source in the central radio frequency circuit; and / or, adjusting the edge radio frequency power of the edge radio frequency source in the edge radio frequency circuit. Alternatively, adjusting the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region may specifically include: adjusting the parameters of the circuit elements related to the central coil assembly in the central radio frequency circuit; and / or, adjusting the parameters of the circuit elements related to the edge coil assembly in the edge radio frequency circuit.

[0150] After performing step S5075, return to step S503, and continue to use the central optical detection device and the edge optical detection device to respectively and real-time detect the central optical signal related to the etching rate in the central region and the edge optical signal related to the etching rate in the edge region.

[0151] As can be seen from the above, the embodiments of the present disclosure provide a control method for a plasma etching process, which uses a central optical detection device to detect the central optical signal in the central region of the plasma etching chamber and an edge optical detection device to detect the central optical signal in the edge region of the plasma etching chamber, thereby obtaining the etching rate in the central region and the etching rate in the edge region, and when it is determined that the etching rate difference between the etching rate in the central region and the etching rate in the edge region exceeds a preset etching threshold range, adjusting the radio frequency power of at least one of the central region and the edge region. Compared with the related art, the control method for the plasma etching process provided by the present disclosure can comprehensively monitor the etching in each region of the plasma etching chamber, and when it is found that the etching rates of the middle region and the edge region are quite different, adjust the radio frequency power of at least one of the central region and the edge region so that the etching rates of the central region and the edge region can reach consistency or overall balance, which can ensure the normal operation of the related process and provide the quality of the etching process.

[0152] Please refer to Figure 7 which shows a schematic flowchart of the control method for the plasma etching process provided by the present disclosure in another embodiment. In this embodiment, it is implemented by a control device in the plasma etching equipment. In the plasma etching equipment, there is a plasma etching chamber. In the central area of the plasma etching chamber, there are a central coil assembly and a central optical detection device, and in the edge area of the plasma etching chamber, there are an edge coil assembly and an edge optical detection device.

[0153] Step S601: Receive the central optical signal related to the central area detected in real time by the central optical detection device and the edge optical signal related to the edge area detected in real time by the edge optical detection device.

[0154] In some embodiments, the central optical detection device and the edge optical detection device are optical emission spectrum detection devices. The spectrum information of the plasma can be detected by the optical emission spectrum detection device. Among them, the spectrum information of the plasma includes the intensity information of the spectrum and / or the change information of the spectrum intensity.

[0155] Step S603: Obtain the etching rate of the central area and the etching rate of the edge area according to the central optical signal and the edge optical signal.

[0156] In step S603, the obtaining of the etching rate of the central area and the etching rate of the edge area according to the central optical signal and the edge optical signal includes: extracting the features of the spectrum information of the central optical signal, and identifying the characteristic spectral lines related to the etching rate; calculating the etching rate of the central area based on the correlation between the intensity of the characteristic spectral lines and the etching rate; extracting the features of the spectrum information of the edge optical signal, and identifying the characteristic spectral lines related to the etching rate; calculating the etching rate of the edge area based on the correlation between the intensity of the characteristic spectral lines and the etching rate.

[0157] Step S605: Calculate the difference between the etching rates of the two according to the etching rate of the central area and the etching rate of the edge area.

[0158] In some embodiments, the difference between the etching rate of the central area and the etching rate of the edge area is the absolute difference of the etching rate, that is, the absolute difference of the etching rates of the two is directly obtained by subtracting the etching rate of the central area from the etching rate of the edge area.

[0159] In some embodiments, the etching rate difference between the etching rate of the central region and the etching rate of the edge region is the etching rate deviation, that is, the etching rate deviation is the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region, or the etching rate deviation is the ratio of the difference between the etching rate of the edge region and the etching rate of the central region to the etching rate of the central region.

[0160] Step S607: Compare the etching rate difference with a preset etching threshold range to determine whether the etching rate difference is within the etching threshold range.

[0161] In step S607, compare the etching rate difference calculated in step S605 with the preset etching threshold range. If the etching rate difference exceeds the etching threshold range, proceed to step S609; if the etching rate difference is within the etching threshold range, it indicates that the etching rates of the central region and the edge region are substantially the same.

[0162] In some embodiments, the etching rate difference between the etching rate of the central region and the etching rate of the edge region is the absolute etching rate difference, and the preset etching threshold range is the absolute etching rate difference threshold range. Compare the absolute etching rate difference with the preset absolute etching rate difference threshold range.

[0163] In some embodiments, the etching rate difference between the etching rate of the central region and the etching rate of the edge region is the etching rate deviation, the preset etching threshold range is the etching deviation threshold range, and the etching rate deviation is the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region, or the etching rate deviation is the ratio of the difference between the etching rate of the edge region and the etching rate of the central region to the etching rate of the central region. That is, calculate the etching rate deviation between the etching rate of the central region and the etching rate of the edge region, and compare the etching rate deviation with the preset etching deviation threshold range.

[0164] Step S609: Generate a power adjustment instruction to adjust the RF power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

[0165] In some embodiments, the etching rate difference between the etching rate of the central region and the etching rate of the edge region is the absolute etching rate difference, and the preset etching threshold range is the absolute etching rate difference threshold range.

[0166] For example, the absolute difference in the etching rates between the central region and the edge region is directly calculated and compared with a preset range of etching absolute difference thresholds. If the comparison result shows that the absolute difference in etching rates exceeds the lower limit of the etching absolute difference threshold range, it indicates that the etching rate of the central region is lower than that of the edge region and the difference in their etching rates is relatively large. A power adjustment instruction is generated, either increasing the RF power of the central coil assembly in the central region, or decreasing the RF power of the edge coil assembly in the edge region, or simultaneously increasing the RF power of the central coil assembly in the central region and decreasing the RF power of the edge coil assembly in the edge region.

[0167] For example, the absolute difference in the etching rates between the central region and the edge region is directly calculated and compared with a preset range of etching absolute difference thresholds. If the comparison result shows that the absolute difference in etching rates exceeds the upper limit of the etching absolute difference threshold range, it indicates that the etching rate of the central region is higher than that of the edge region and the difference in their etching rates is relatively large. A power adjustment instruction is generated, either decreasing the RF power of the central coil assembly in the central region, or increasing the RF power of the edge coil assembly in the edge region, or simultaneously decreasing the RF power of the central coil assembly in the central region and increasing the RF power of the edge coil assembly in the edge region.

[0168] In some embodiments, the etching rate difference between the etching rate of the central region and the etching rate of the edge region is the etching rate deviation, the preset etching threshold range is the etching deviation threshold range, the etching rate deviation is the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region, or the etching rate deviation is the ratio of the difference between the etching rate of the edge region and the etching rate of the central region to the etching rate of the central region.

[0169] For example, the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region is calculated to obtain the etching rate deviation between the two. The etching rate deviation is compared with a preset range of etching deviation thresholds. If the comparison result shows that the etching rate deviation exceeds the lower limit of the etching deviation threshold range, it indicates that the etching rate of the central region is lower than that of the edge region and the difference in their etching rates is relatively large. A power adjustment instruction is generated, either increasing the RF power of the central coil assembly in the central region, or decreasing the RF power of the edge coil assembly in the edge region, or simultaneously increasing the RF power of the central coil assembly in the central region and decreasing the RF power of the edge coil assembly in the edge region.

[0170] For example, the etching rate deviation between the central region and the edge region is obtained by calculating the ratio of the difference between the etching rate of the central region and the etching rate of the edge region to the etching rate of the edge region. Comparing the etching rate deviation with a preset etching deviation threshold range, if the comparison result shows that the etching rate deviation exceeds the upper limit of the etching deviation threshold range, it indicates that the etching rate of the central region is greater than that of the edge region and the difference in their etching rates is large. Then, a power adjustment instruction is generated, which may either reduce the RF power of the central coil assembly in the central region, or increase the RF power of the edge coil assembly in the edge region, or simultaneously reduce the RF power of the central coil assembly in the central region and increase the RF power of the edge coil assembly in the edge region.

[0171] In some embodiments, in the plasma etching equipment, the central coil assembly and the edge coil assembly are connected to the RF source in parallel. Therefore, in step S609, adjusting the RF power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region may specifically include: generating a central power adjustment instruction, and adjusting the parameters of the circuit elements in the central RF branch where the central coil assembly is located according to the central power adjustment instruction; and / or, generating an edge power adjustment instruction, and adjusting the parameters of the circuit elements in the edge RF branch where the edge coil assembly is located according to the edge power adjustment instruction. The circuit elements may be, for example, adjustable capacitors, or adjustable inductors, or adjustable resistors, etc.

[0172] In some embodiments, in the plasma etching equipment, the central coil assembly is connected to a central RF source to form a central RF circuit, and the edge coil assembly is connected to an edge RF source to form an edge RF circuit, and the central RF circuit and the edge RF circuit are independent of each other. Therefore, in step S609, adjusting the RF power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region may specifically include: generating a central power adjustment instruction, and adjusting the RF power of the central RF source in the central RF circuit according to the central power adjustment instruction; and / or, generating an edge power adjustment instruction, and adjusting the edge RF power of the edge RF source in the edge RF circuit according to the edge power adjustment instruction. Or, adjusting the RF power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region may specifically include: generating a central power adjustment instruction, and adjusting the parameters of the circuit elements related to the central coil assembly in the central RF circuit according to the central power adjustment instruction; and / or, generating an edge power adjustment instruction, and adjusting the parameters of the circuit elements related to the edge coil assembly in the edge RF circuit according to the edge power adjustment instruction.

[0173] After performing step S609, return to step S601 to continue receiving the central optical signal related to the central region detected in real time by the central optical detection device and the edge optical signal related to the edge region detected in real time by the edge optical detection device.

[0174] As can be seen from the above, the embodiments of the present disclosure provide a control method for a plasma etching process, which receives the central optical signal related to the central region detected in real time by the central optical detection device and the edge optical signal related to the edge region detected in real time by the edge optical detection device, thereby obtaining the etching rate of the central region and the etching rate of the edge region. When it is determined that the etching rate difference between the etching rate of the central region and the etching rate of the edge region exceeds a preset etching threshold range, a power adjustment instruction is generated to adjust the radio frequency power of at least one of the central region and the edge region. Compared with the related art, the control method for the plasma etching process provided by the present disclosure can comprehensively monitor the etching of each region in the plasma etching chamber, and when it is found that the etching rates of the middle region and the edge region are quite different, adjust the radio frequency power of at least one of the central region and the edge region so that the etching rates of the central region and the edge region can reach consistency or overall balance, which can ensure the normal operation of related processes and provide the quality of the etching process.

[0175] The embodiments of the present disclosure further provide a control device. In some embodiments, the control device may be, for example, a host computer, and the host computer is connected to a multi-channel gas inlet device, an exhaust device, etc.

[0176] Please refer to Figure 8 , which shows the principle block diagram of the control device provided by the present disclosure in an embodiment.

[0177] As Figure 8 shown, the control device 8 includes a processor 81 and a memory 83. The processor 81 and the memory 83 can communicate through a bus 82. A control program for the plasma etching process may be stored in the memory 83. The processor 81 executes each step in the control method for the plasma etching process by running the control program for the plasma etching process in the memory 83.

[0178] The bus 82 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of convenience of representation, although only a thick line is used in the figure, it does not mean that there is only one bus or one type of bus.

[0179] In some embodiments, the processor 81 may be implemented as a Central Processing Unit (CPU), a Micro Controller Unit (MCU), a System on Chip (SoC), or a Field Programmable Gate Array (FPGA), etc. The memory 83 may include volatile memory for temporarily storing data when the program is running, such as Random Access Memory (RAM). The memory 83 may also include non-volatile memory (Non-Volatile Memory; NVM) for data storage, such as Read-Only Memory (ROM), flash memory, a Hard Disk Drive (HDD), or a Solid-State Disk (SSD).

[0180] In practical applications, the control device may be associated with a multi-channel intake device and an exhaust device, etc., for controlling each component in the intake device and each component in the exhaust device. By setting relevant conditions, the air supply state of one calibrated intake device to be calibrated is made to approach the air supply state of the reference intake device, and the gas pressure regulating valve is gradually fine-tuned, so that the gas flow rate generated by the gas pressure regulating valve in the calibrated intake device is the same as or substantially the same as the gas flow rate controlled by the reference intake device, thereby achieving the equivalence of the calibrated intake device and the reference intake device in gas flow control, and thus realizing the equivalence of the gas pressure regulating valve as a flow controller, reducing the usage amount of flow controllers, and effectively reducing costs.

[0181] The embodiments of the present disclosure may also provide a computer-readable storage medium storing a computer program or instruction, and when the computer program or instruction is run, it implements the process or function of the control method for the plasma etching process in any of the foregoing embodiments.

[0182] That is, the method steps in the above embodiments are implemented as software or computer code that can be stored in a recording medium (such as a CD ROM, RAM, floppy disk, hard disk, or magneto-optical disk), or as computer code that is originally stored in a remote recording medium or a non-transitory machine-readable medium and downloaded through a network and will be stored in a local recording medium, so that the method represented herein can be stored on such a recording medium for software processing using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or an FPGA).

[0183] In an embodiment of the present disclosure, a computer program product may also be provided, and a plurality of computer programs or instructions, when run, fully or partially execute the processes or functions of the control method of the plasma etching process in the embodiments of the present disclosure. The computer program product includes a plurality of computer programs or instructions.

[0184] The computer programs or instructions may be stored in a readable storage medium, or transmitted from one readable storage medium to another. For example, the computer programs or instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless manner. The readable storage medium may be any available medium that can be accessed or a data storage device such as a server or data center integrating a plurality of available media. The available medium may be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it may also be an optical medium, such as a digital video disc; or it may be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both volatile and non-volatile types of storage media.

[0185] The above embodiments merely illustrate the principles and effects of the present disclosure and are not intended to limit the present disclosure. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present disclosure. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present disclosure should still be covered by the protection scope of the present disclosure.

Claims

1. A control method for a plasma etching process, characterized in that Applied to a plasma etching equipment, the control method of the plasma etching process comprises the following steps: A central optical detection device and an edge optical detection device are respectively arranged in the central area and the edge area at the upper part of the plasma etching cavity; wherein, a central coil assembly is arranged in the central area, and an edge coil assembly is arranged in the edge area; The central optical detection device and the edge optical detection device are respectively used to detect in real time a central optical signal related to the etching rate in the central area and an edge optical signal related to the etching rate in the edge area; According to the central optical signal and the edge optical signal, the etching rate in the central area and the etching rate in the edge area are obtained; and When it is determined that the etching rate difference between the etching rate in the central area and the etching rate in the edge area exceeds a preset etching threshold range, the radio frequency power of at least one of the central coil assembly in the central area and the edge coil assembly in the edge area is adjusted.

2. The control method of the plasma etching process according to claim 1, wherein, The step of obtaining the etching rate in the central area and the etching rate in the edge area according to the central optical signal and the edge optical signal comprises the following steps: Performing feature extraction on the spectral information of the central optical signal to identify a characteristic spectral line related to the etching rate; Calculating the etching rate in the central area based on the correlation between the intensity of the characteristic spectral line and the etching rate; And Performing feature extraction on the spectral information of the edge optical signal to identify a characteristic spectral line related to the etching rate; Calculating the etching rate in the edge area based on the correlation between the intensity of the characteristic spectral line and the etching rate.

3. The control method of the plasma etching process according to claim 1, wherein In the plasma etching equipment, the central coil assembly and the edge coil assembly are connected to a radio frequency source in a parallel manner; the step of adjusting the radio frequency power of at least one of the central coil in the central area and the edge coil assembly in the edge area comprises the following steps: Adjusting the parameters of the circuit elements in the central radio frequency branch where the central coil assembly is located; and / or, adjusting the parameters of the circuit elements in the edge radio frequency branch where the edge coil assembly is located.

4. The control method of the plasma etching process according to claim 1, characterized in that, In the plasma etching equipment, the central coil assembly is connected to a central radio frequency source to form a central radio frequency circuit, and the edge coil assembly is connected to an edge radio frequency source to form an edge radio frequency circuit; the step of adjusting the radio frequency power of at least one of the central coil in the central area and the edge coil assembly in the edge area comprises the following steps: Adjusting the radio frequency power of the central radio frequency source in the central radio frequency circuit; and / or, adjusting the edge radio frequency power of the edge radio frequency source in the edge radio frequency circuit; or Adjusting the parameters of the circuit elements related to the central coil assembly in the central radio frequency circuit; and / or, adjusting the parameters of the circuit elements related to the edge coil assembly in the edge radio frequency circuit.

5. A control method for a plasma etching process, characterized in that, Applied to a plasma etching equipment, the plasma etching equipment comprises a plasma etching cavity, a central coil assembly and a central optical detection device are arranged in the central area of the plasma etching cavity, and an edge coil assembly and an edge optical detection device are arranged in the edge area of the plasma etching cavity; the control method of the plasma etching process comprises the following steps: Receive the central optical signal related to the central region detected in real time by the central optical detection device and the edge optical signal related to the edge region detected in real time by the edge optical detection device; Obtain the etching rate of the central region and the etching rate of the edge region according to the central optical signal and the edge optical signal; And When it is determined that the etching rate difference between the etching rate of the central region and the etching rate of the edge region exceeds the preset etching threshold range, generate a power adjustment instruction to adjust the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

6. The control method of the plasma etching process according to claim 5, characterized in that, In the plasma etching equipment, the central coil assembly and the edge coil assembly are connected to the radio frequency source in parallel; the adjustment of the radio frequency power of at least one of the central coil in the central region and the edge coil assembly in the edge region includes the following steps: Generate a central power adjustment instruction, and according to the central power adjustment instruction, adjust the parameters of the circuit elements in the central radio frequency branch where the central coil assembly is located; and / or, generate an edge power adjustment instruction, and according to the edge power adjustment instruction, adjust the parameters of the circuit elements in the edge radio frequency branch where the edge coil assembly is located.

7. The control method of the plasma etching process according to claim 5, wherein In the plasma etching equipment, the central coil assembly is connected to the central radio frequency source to form a central radio frequency circuit, and the edge coil assembly is connected to the edge radio frequency source to form an edge radio frequency circuit; the adjustment of the radio frequency power of at least one of the central coil in the central region and the edge coil assembly in the edge region includes the following steps: Generate a central power adjustment instruction, and according to the central power adjustment instruction, adjust the radio frequency power of the central radio frequency source in the central radio frequency circuit; and / or, generate an edge power adjustment instruction, and according to the edge power adjustment instruction, adjust the edge radio frequency power of the edge radio frequency source in the edge radio frequency circuit; or, Generate a central power adjustment instruction, and according to the central power adjustment instruction, adjust the parameters of the circuit elements related to the central coil assembly in the central radio frequency circuit; and / or, generate an edge power adjustment instruction, and according to the edge power adjustment instruction, adjust the parameters of the circuit elements related to the edge coil assembly in the edge radio frequency circuit.

8. A plasma etching device, characterized in that, Comprising: A plasma etching chamber; A central coil assembly and an edge coil assembly, which are respectively arranged in the central region and the edge region at the upper part of the plasma etching chamber; A central optical detection device and an edge optical detection device, which are respectively configured in the central region and the edge region; A control device, which is communicatively connected to the central coil assembly, the edge coil assembly, the central optical detection device and the edge optical detection, and is used to obtain the etching rate of the central region and the etching rate of the edge region according to the central optical signal detected in real time by the central optical detection device and the edge optical signal detected in real time by the edge optical detection device, and when it is determined that the etching rate difference between the etching rate of the central region and the etching rate of the edge region exceeds the preset etching threshold range, generate a power adjustment instruction to adjust the radio frequency power of at least one of the central coil assembly in the central region and the edge coil assembly in the edge region.

9. A control device, characterized in that, Comprising: A processor; A memory that stores a control program for a plasma etching process; Wherein, when the control program for the plasma etching process is run by the processor, it executes the control method for the plasma etching process according to any one of claims 5 to 7.

10. A computer-readable storage medium, on which a control program for a plasma etching process is stored, characterized in that, When the control program for the plasma etching process is executed by the processor, it implements the control method for the plasma etching process according to any one of claims 5 to 7.

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