High aspect ratio etching structure morphology improvement method, etching equipment and semiconductor structure

Abstract

The invention discloses a high aspect ratio etching structure morphology improvement method, etching equipment and a semiconductor structure. The method comprises the following steps: forming plasma with continuously increased density in a first space; enabling the plasmas to be dispersed through the bottom of the first space under the natural action of pressure and to be diffused downwards into the second space, so as to form the plasmas with the density tending to be uniform on the whole surface of the substrate when the plasmas reach the surface of the substrate in the second space; the method comprises the following steps: performing downward etching on the surface of a substrate through plasma to form a plurality of high aspect ratio etching structures distributed on the substrate, and in the etching process, applying an extra local correction electric field to a target improvement region on the substrate according to the obtained inclination generation region and inclination degree data of the high aspect ratio etching structures, so as to improve the target improvement region on the substrate. And adjusting the electric field intensity of the local correction electric field to a preset value. According to the invention, the abnormal morphology of etching inclination can be effectively solved, and the electrical performance and mechanical reliability of the device are ensured.

Description

Technical Field

[0001] The present application relates to the field of semiconductor processing technology, and in particular to a method for improving the morphology of a high aspect ratio etching structure, an etching device and a semiconductor structure. Background Art

[0002] As packaging density continues to increase, TSV processes have been commonly used in advanced packaging technology to achieve interlayer interconnection in three-dimensional integrated circuits. Moreover, as wafer size continues to increase, higher requirements are placed on the etching uniformity of TSVs with high aspect ratios.

[0003] Groove tilt refers to an etching morphology defect in which the etching deviates from the vertical direction during the etching process, causing the side walls of the formed silicon via to tilt toward the same side. This defect will affect the electrical performance and mechanical reliability of the silicon via. Therefore, it is necessary to study a process method that can improve the groove tilt defect. Summary of the invention

[0004] The purpose of the present application is to overcome the above-mentioned problems existing in the prior art and to provide a method for improving the morphology of a high aspect ratio etching structure, an etching device and a semiconductor structure to improve the groove tilt defect.

[0005] To achieve the above objectives, the technical solution of this application is as follows: According to the first aspect of the present application, an embodiment of the present application provides a method for improving the morphology of a high aspect ratio etching structure, comprising: forming a plasma with a continuously increasing density in the first space; The plasma is dispersed through the bottom of the first space and diffused downward into the second space under the natural effect of pressure, so that when the plasma reaches the surface of the substrate located in the second space, the plasma with a uniform density is formed on the entire surface of the substrate; The surface of the substrate is etched downward by the plasma to form a plurality of high aspect ratio etching structures distributed on the substrate, and during the etching process, an additional local correction electric field is applied to the target improvement area on the substrate according to the acquired data on the tilt occurrence area and tilt size of the high aspect ratio etching structure, and the electric field strength of the local correction electric field is adjusted to a preset value.

[0006] In some embodiments, in a direction from the center to the edge of the substrate, the plasma is vertically dispersed into multiple plasma gas flows from sparse to dense at the bottom of the first space, and diffused downward into the second space.

[0007] In some embodiments, in a direction from the center to the edge of the substrate, the plasma is vertically dispersed into a plurality of plasma gas flows with diameters increasing from small to large at the bottom of the first space, and diffused downward into the second space.

[0008] In some embodiments, a central area and an edge area surrounding the central area are defined on the surface of the substrate, the target improvement area is located in the edge area, the local correction electric field is applied to the edge area, and a plurality of application areas of the local correction electric field are configured around the central area.

[0009] In some embodiments, the local correction electric field is generated by applying an alternating voltage, and the power required to be applied to the local correction electric field to reach the preset value is 1% to 5% of the bias power applied to the substrate as a whole, and the preset value is proportional to the size of the inclination.

[0010] In some embodiments, the number of application areas of the local correction electric field is 4 to 16 evenly distributed.

[0011] In some embodiments, the etching is performed based on a modified Bosch process, which is a pulsed plasma etching process using helium protection.

[0012] In some embodiments, during etching, the temperature is 10° C. to 60° C., the pressure is 1 mtorr to 100 mtorr, the source power is 100 W to 2000 W, and the bias power is 10 W to 500 W.

[0013] According to the second aspect of the present application, an embodiment of the present application further provides an etching device, including: A cavity, wherein a base is provided on the bottom of the cavity, and a substrate is provided on the base; a gas storage module, arranged in the cavity, the gas storage module having a first space, the first space being located above the pedestal, a second space being located below the first space, the pedestal being accommodated in the second space, the gas storage module being used to form a plasma with a continuously increasing density in the first space, and to disperse the plasma through the bottom of the first space and diffuse downward into the second space under the natural effect of pressure, so that when the plasma reaches the surface of the substrate arranged on the pedestal, the plasma with a uniform density is formed on the entire surface of the substrate, and then the surface of the substrate is etched downward by the plasma to form a plurality of high aspect ratio etching structures distributed on the substrate; A local correction electric field generating module is arranged on the base. The local correction electric field generating module is used to apply the generated additional local correction electric field to the target improvement area on the substrate during the etching process according to the obtained data on the tilt occurrence area and tilt size of the high aspect ratio etching structure, and adjust the electric field strength of the local correction electric field to a preset value.

[0014] In some embodiments, the gas storage module includes an air flow dispersion plate, which is horizontally arranged above the base, and the side of the air flow dispersion plate is in close contact with the side wall of the cavity, and the first space and the second space are respectively formed in the cavity on the upper and lower sides of the air flow dispersion plate, and a plurality of nanopores are provided on the surface of the air flow dispersion plate, and the nanopores are perpendicular to the surface of the horizontally arranged substrate, and the nanopores are used to pass the plasma, and the arrangement form of each of the nanopores is: in the direction from the center to the edge of the substrate, each of the nanopores is distributed from sparse to dense.

[0015] In some embodiments, the nanopores are arranged in such a manner that the apertures of the nanopores are distributed from small to large in a direction from the center to the edge of the substrate. In some embodiments, the local correction electric field generating module includes a plurality of independently arranged first electrodes, the surface of the substrate includes a central area and an edge area surrounding the central area, the target improvement area is located in the edge area, the setting position of each of the first electrodes on the base is located on the edge area, and is evenly arranged around the central area, and the local correction electric field is generated by applying an alternating voltage to the first electrodes corresponding to the positions of the target improvement areas.

[0016] In some embodiments, the etching equipment is used to perform a pulsed plasma etching process using helium protection.

[0017] In some embodiments, the air flow dispersion plate is made of insulating material.

[0018] In some embodiments, an air inlet is provided on the top of the cavity, and the air inlet is connected to the top of the first space, the air inlet is used to introduce process gas into the first space to form the plasma, a first distance between the air inlet and the surface of the substrate when set is 100mm to 200mm, and a second distance between the air flow dispersion plate and the surface of the substrate when set is 20mm to 60mm.

[0019] In some embodiments, the pore occupancy of the nanopores on the airflow dispersion plate gradually increases from 10% to 50% along the center to the edge of the substrate.

[0020] In some embodiments, the diameter of the nanopores gradually increases from 1 nm to 100 nm along the center to the edge of the substrate.

[0021] In some embodiments, a second electrode is further provided on the base for applying bias power to the entire substrate. The power required to be applied to the first electrode when the preset value is reached is 1% to 5% of the applied bias power, and the preset value is proportional to the size of the inclination.

[0022] In some embodiments, the number of the first electrodes is 4 to 16.

[0023] According to the third aspect of the present application, an embodiment of the present application further provides a semiconductor structure, comprising a substrate and a plurality of high aspect ratio etching structures distributed on the substrate, wherein the high aspect ratio etching structure is manufactured using the high aspect ratio etching structure morphology improvement method provided in any one of the embodiments of the first aspect above. Alternatively, the high aspect ratio etching structure is manufactured using the etching equipment provided in any one of the embodiments of the second aspect above.

[0024] The embodiments of the present application may or at least have the following advantages: (1) By utilizing the pressure effect, the plasma formed in the first space is first pressurized and stored, so that the density of the plasma continues to increase. Then, under the natural effect of pressure, the plasma is dispersed through the bottom of the first space and diffused downward into the second space, so as to form a plasma with a uniform density on the entire surface of the substrate, thereby achieving uniform distribution of the process gas (plasma) on the entire surface of the substrate. In addition, during the etching process of the high aspect ratio etching structure, according to the obtained data on the tilt occurrence area and tilt size of the high aspect ratio etching structure, an additional local correction electric field is applied to the target improvement area on the substrate, and the electric field strength of the local correction electric field is adjusted to a preset value, thereby constructing an electrostatic field with adjustable area and adjustable intensity, thereby enhancing anisotropic etching, thereby optimizing the gas field and local electric field during the etching process of the high aspect ratio etching structure, and effectively solving the abnormal morphology of etching tilt from the middle to the edge of the substrate and in different areas of the edge caused by the uneven distribution of the gas field and the electromagnetic field.

[0025] (2) By evenly distributing the process gas over the entire surface of the substrate and constructing an electrostatic field with adjustable area and intensity, a higher etching rate and stronger anisotropic effect can be achieved, which is beneficial to high aspect ratio etching and improves the process window.

[0026] (3) By effectively improving the abnormal morphology of etching tilt produced on the substrate, the electrical performance and mechanical reliability of the device are guaranteed, thereby improving the yield and stability of the device.

[0027] Other advantages of the present application will be described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 A schematic diagram of a groove structure with an abnormal morphology in which etching is tilted at the edge of a substrate.

[0028] Figure 2 A schematic diagram of using an existing etching device for process gas blowing.

[0029] Figure 3 A flowchart of a method for improving the morphology of a high aspect ratio etched structure provided in a preferred embodiment of the present application.

[0030] Figure 4 A schematic structural diagram of an etching device provided in a preferred embodiment of the present application.

[0031] Figure 5 A schematic diagram of a planar distribution structure of a first electrode provided in a preferred embodiment of the present application.

[0032] Figure 6 For use Figure 4 Schematic diagram of the etching equipment during process gas blowing.

[0033] Figure 7 An electron microscope schematic diagram of the inclined morphology of a groove provided as a comparative example.

[0034] Figure 8 This is an electron microscope schematic diagram of the vertical morphology of the groove obtained after improving the groove tilt morphology.

[0035] In the figure, 10. cavity; 11. base; 12. air inlet; 13. exhaust; 100. substrate; 101. groove; 201. first space; 202. second space; 2011. bottom of the first space; 22. gas storage module; 221. air flow dispersion plate; 222. nanopores; 24. local corrected electric field generating module; 241. first electrode; A. central area; B. edge area. DETAILED DESCRIPTION

[0036] During the etching process of high aspect ratio through silicon via (TSV), due to the local uneven distribution of electromagnetic field / plasma, the etching deviates from the vertical direction, resulting in the etching morphology defect of trench tilting. This defect will affect the electrical performance and mechanical reliability of the through silicon via. However, there are still the following technical difficulties in improving the etching morphology defect of trench tilting: (1) Since etching is a reaction kinetic behavior, traditional offline monitoring methods (such as SEM) are difficult to monitor the reaction process in the chamber in real time and optimize the process parameters at any time.

[0037] (2) When etching deep holes (such as when the aspect ratio is greater than 20:1), it is difficult to maintain uniform plasma density and ion energy distribution, resulting in significant differences in etching rates in different areas and between the top and bottom of the same area, causing a tilted groove morphology.

[0038] (3) When using the traditional Bosch process for trench etching, vertical etching is achieved by alternating etching and passivation cycles. However, slight deviations in the cycle switching time, gas ratio, and power parameters can easily lead to uneven local etching and passivation, causing the etching to deviate from the vertical direction.

[0039] (4) The density of the plasma generated by the RF coil decreases at the edge of the wafer substrate, resulting in differences in plasma density on the wafer surface.

[0040] refer to Figure 1 , which shows a plurality of trenches 101 (Through Silicon Vias) distributed on a substrate 100 (silicon wafer) fabricated by a conventional etching process (e.g., Bosch process). The surface of the substrate 100 includes a central region A and an edge region B, and the above-mentioned trench tilt defect usually occurs in the edge region B. For example, Figure 1 The diagram schematically shows the abnormal morphology of two inclined grooves 101 located in the edge region B (the bottom of the groove is inclined toward the outside of the substrate 100 ), and the diagram schematically shows the normal morphology of four vertical grooves 101 located in the central region A.

[0041] Figure 7 Shows the actual morphology of a groove when it is tilted ( Figure 7 Mark 1 indicates that the depth in the Y direction is 1.3908 microns, mark 2 indicates that the top width in the X direction is 1.9807 microns, and mark 3 indicates that the bottom width in the X direction is 1.9807 microns). The groove inclination is about 2 degrees.

[0042] refer to Figure 2, which shows the uneven distribution effect of process gas on the surface of substrate 100 when an existing blowing method is adopted. An existing inductively coupled plasma (ICP) etching device includes a chamber 10, an air inlet 12 (such as an air nozzle) is provided on the top of the chamber 10, a base 11 (such as an electrostatic chuck) for setting the substrate 100 (such as a wafer) is provided on the bottom of the chamber 10, and an exhaust part 13 (such as an exhaust port) for exhaust is provided. The air inlet 12 is used to input the process gas for etching into the chamber 10. The process gas is excited to form plasma through the radio frequency coil provided on the chamber 10, and is introduced downward to the surface of the placed substrate 100 under the action of bias power for etching. Since the area of ​​the air inlet 12 is much smaller than the area of ​​the substrate 100, it is easy to cause an uneven distribution phenomenon in which the plasma density is high in the middle and low at the edge, resulting in differences in the plasma density on the surface of the substrate 100. In addition, the actual electromagnetic field strength acting on the edge area B is often smaller than that in the center area A. The above factors lead to the frequent problem of groove tilting in the edge area B.

[0043] In order to solve the above-mentioned problems existing in the prior art, the embodiments of the present application provide a method for improving the morphology of a high aspect ratio etching structure, an etching device and a semiconductor structure to improve the groove tilt defect.

[0044] The specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings.

[0045] refer to Figure 3 The embodiment of the present application provides a method for improving the morphology of a high aspect ratio etching structure, comprising: forming a plasma with a continuously increasing density in the first space; Allowing the plasma to be dispersed through the bottom of the first space and diffuse downward into the second space under the natural effect of pressure, so that when the plasma reaches the surface of the substrate located in the second space, a plasma with a uniform density is formed on the entire surface of the substrate; The surface of the substrate is etched downward by plasma to form a plurality of high aspect ratio etching structures distributed on the substrate, and during the etching process, an additional local correction electric field is applied to the target improvement area on the substrate according to the obtained data on the tilt occurrence area and tilt size of the high aspect ratio etching structure, and the electric field strength of the local correction electric field is adjusted to a preset value.

[0046] The above-mentioned embodiment of the present application provides a method for improving the morphology of a high aspect ratio etching structure. By utilizing the pressure effect, the plasma formed in the first space is first pressurized and stored, so that the density of the plasma continues to increase. Then, under the natural effect of the pressure, the plasma is dispersed through the bottom of the first space and diffused downward to the second space, so as to form a plasma with a uniform density on the entire surface of the substrate, so as to achieve a uniform distribution of the process gas (plasma) on the entire surface of the substrate, and in the etching process of the high aspect ratio etching structure, the inclination of the high aspect ratio etching structure on the previous substrate that has completed the etching process of the high aspect ratio etching structure is measured. The pre-acquired tilt occurrence area and tilt size data of the high aspect ratio etching structure are used to apply an additional local correction electric field to the target improvement area on the current substrate (i.e., the tilt occurrence area on the previous substrate), and adjust the electric field strength of the local correction electric field to a preset value to construct an electrostatic field with adjustable area and intensity to enhance the physical bombardment effect and strengthen anisotropic etching, thereby optimizing the gas field and local electric field in the etching process of the high aspect ratio etching structure, and effectively solving the abnormal morphology of etching tilt from the middle to the edge of the substrate and in different areas of the edge caused by the uneven distribution of the gas field and the electromagnetic field.

[0047] In some embodiments, the high aspect ratio etching structure includes a trench with a depth to aspect ratio of 20:1 or more, a deep via, or a through via, etc. The following takes the high aspect ratio etching structure as a trench with a depth to aspect ratio of 20:1 or more as an example to describe the embodiments of the present application in detail.

[0048] refer to Figure 4 and Figure 6 In some embodiments, a cavity 10 for performing an etching process may be used, and a first space 201 and a second space 202 may be set in the cavity 10. The first space 201 and the second space 202 are arranged up and down, and the first space 201 and the second space 202 are connected and isolated by the bottom 2011 of the first space. The first space 201 and the second space 202 are relatively closed environments. The second space 202 is used to set the substrate 100 (for example, a wafer).

[0049] In some embodiments, a plurality of tiny hollow portions may be provided on the bottom 2011 of the first space.

[0050] In some embodiments, the hollow portion may be an air hole.

[0051] In some embodiments, the size of the pores can be nanometer-sized, so that when ventilation (process gas) is continuously conducted into the first space 201, the nanometer-sized pores (nanopores 222) can hinder the airflow to a certain extent, so that the gas output through the bottom 2011 of the first space is smaller than the gas input when ventilation is conducted into the first space 201, thereby achieving the effect of storing gas under a certain air pressure in the first space 201 above the bottom 2011 of the first space, until the air pressure in the first space 201 increases to a state where the gas input and gas output reach a dynamic equilibrium, thereby achieving the purpose of stably transporting the gas stored in the first space 201 to the second space 202.

[0052] In some embodiments, the boundaries of the orthographic projections of all the pores on the bottom 2011 of the first space in the vertical direction will at least completely cover the surface of the substrate 100 horizontally disposed in the second space 202 .

[0053] In some embodiments, plasma is formed by excited etching process gas. By continuously passing the process gas into the first space 201, the process gas is continuously pressurized and stored in the first space 201 (i.e., the density of the process gas is continuously increased), and the process gas is relatively evenly distributed in the relatively closed first space 201 during this process, so that the density of the process gas at each position in the first space 201 is relatively consistent. The process gas after entering the first space 201 is excited in the first space 201 to form plasma, and the density of the formed plasma also increases with the continuous increase of the density of the process gas until a critical state is reached. In this way, a plasma in a uniform state with a relatively consistent density at each position can be formed in the relatively closed first space 201 through the action of pressure.

[0054] In some embodiments, the substrate 100 is horizontally disposed in the second space 202. When the gas pressure in the first space 201 reaches a certain level (a state where the inlet and outlet gas volumes reach a dynamic equilibrium, a critical state), the plasma formed in the first space 201 will be dispersed and diffused downward to the second space 202 through the nano-pores 222 on the bottom 2011 of the first space under the natural effect of the pressure. In the direction from the center to the edge of the substrate 100, the plasma is vertically dispersed into multiple plasma gas flows from sparse to dense at the bottom 2011 of the first space, and diffused downward to the second space 202.

[0055] In some embodiments, when the substrate 100 is horizontally disposed in the second space 202, the center of the bottom 2011 of the first space is aligned (or substantially aligned) with the center of the substrate 100. In the direction from the center to the edge of the bottom 2011 of the first space, the nanopores 222 are distributed from sparse to dense on the bottom 2011 of the first space, so that the plasma is vertically dispersed into multiple plasma gas flows from sparse to dense at the bottom 2011 of the first space by the nanopores 222, and diffuses downward toward the surface of the substrate 100.

[0056] In some embodiments, at each position of the bottom 2011 of the first space, the apertures of the nanopores 222 are consistent. In this case, the number of nanopores 222 gradually increases in the direction from the center to the edge of the bottom 2011 of the first space (in the direction from the center to the edge of the substrate 100). That is, in the direction from the center to the edge of the bottom 2011 of the first space, the pore occupancy of the nanopores 222 (the area ratio of the nanopores 222 per unit area on the bottom 2011 of the first space) gradually increases.

[0057] In some embodiments, in the direction from the center to the edge of the bottom 2011 of the first space (in the direction from the center to the edge of the substrate 100 ), the plasma is vertically dispersed into multiple plasma gas flows with diameters ranging from small to large at the bottom 2011 of the first space, and diffuses downward into the second space 202 .

[0058] In some embodiments, in the direction from the center to the edge of the bottom 2011 of the first space (in the direction from the center to the edge of the substrate 100), by gradually increasing the aperture of each nanopore 222, the plasma is vertically dispersed into multiple plasma gas flows with diameters from small to large by each nanopore 222 at the bottom 2011 of the first space, and diffused downward into the second space 202. In this case, the number of nanopores 222 gradually increases in the direction from the center to the edge of the bottom 2011 of the first space. Alternatively, in the direction from the center to the edge of the bottom 2011 of the first space, the hole occupancy (opening rate) of the nanopores 222 gradually increases.

[0059] It should be noted that the density of each plasma gas flow when output from each nanopore 222 at the bottom 2011 of the first space is consistent (or substantially consistent), but since the hole occupancy formed by each nanopore 222 along the center to the edge direction of the bottom 2011 of the first space is gradually increased, when the plasma is just output from each nanopore 222 at the bottom 2011 of the first space, the gas output along the center to the edge direction of the bottom 2011 of the first space is gradually increased, showing a state of less gas in the center and more gas at the edge, such as Figure 6As shown by the downward solid arrow in the figure. Afterwards, when the output plasma gradually leaves the bottom 2011 of the first space downward, it will be continuously affected by the negative pressure of the exhaust gas at the bottom of the chamber, so that the airflow at the edge will be attracted to flow outward more than the airflow at the center. Therefore, when the plasma finally contacts the surface of the substrate 100, the amount of the airflow arriving at the edge can be made consistent with the amount of the airflow arriving at the center, and the density of the airflow from the center of the substrate 100 surface to the edge can also be made consistent, as shown in FIG. Figure 6 As shown by the downward hollow arrow in FIG. , when the plasma contacts the surface of the substrate 100 , the plasma is evenly distributed on the surface of the substrate 100 , thereby improving the process uniformity.

[0060] In some embodiments, a central region A and an edge region B surrounding the central region A are defined on the surface of the substrate 100. According to the characteristic that the high aspect ratio etched structure tilting region is usually located in the edge region B (determined according to actual detection), the target improvement region is determined to be located in the edge region B, and the local correction electric field is applied to the edge region B. In addition, multiple local correction electric field application regions are configured around the central region A.

[0061] In some embodiments, the local modified electric field is generated by applying an alternating voltage to the application area of ​​the local modified electric field.

[0062] In some embodiments, the power required to be applied to the local correction electric field when the above-mentioned preset value is reached is 1% to 5% of the bias power conventionally applied to the substrate 100 as a whole. That is, the power required to be applied to the local correction electric field is adjusted with reference to the bias power. For example, the power required to be applied to the local correction electric field when the above-mentioned preset value is reached can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5% of the bias power conventionally applied to the substrate 100 as a whole, but is not limited thereto.

[0063] Moreover, the size of the preset value is proportional to the size of the groove inclination, that is, when the groove inclination is larger, the electric field strength to be applied should be larger, and the preset value is higher, so the power applied to the local correction electric field also needs to be increased accordingly.

[0064] In some embodiments, the number of application areas of the local correction electric field is 4 to 16 evenly distributed around the central area A. For example, the number of application areas of the local correction electric field can be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16.

[0065] It is worth noting that due to the existence of the groove tilt, deep silicon etching easily leads to lateral etching, which in turn affects the etching in the depth direction. The embodiment of the present application evenly distributes the process gas on the entire surface of the substrate 100, and then constructs an electrostatic field with adjustable area and adjustable intensity. Through the locally applied corrected electric field, better etching in the depth direction can be achieved, so the rate will also be faster, thereby being able to exert a higher etching rate and stronger anisotropy, which is beneficial to high aspect ratio etching and improves the process window.

[0066] In some embodiments, the etching process used for trench etching is a modified Bosch process formed by optimizing the traditional Bosch process, and the modified Bosch process is a pulsed plasma etching process using helium protection. The modified Bosch process uses helium (He) as the protective gas, replacing the argon used in the traditional Bosch process, and uses pulsed plasma etching to etch the groove.

[0067] In some embodiments, the modified Bosch process includes a plurality of periodic cycle steps formed by an etching step, a passivation layer deposition step, and an etching step in sequence. In the embodiment of the present application, a pulsed plasma etching method with helium protection is used when performing the modified Bosch process. Specifically, the pulsed plasma etching method includes a plurality of periodic pulse cycle steps formed by alternately turning on and off the bias power.

[0068] Among them, in the multiple periodic cycle steps formed by the etching step, the passivation layer deposition step, and the etching step, the pulsed plasma etching method is used in the etching step (link). When the bias power is turned on, high-energy ions are generated to bombard the surface of the substrate 100 to activate the etching reaction. When the bias power is turned off, the plasma is extinguished or the power drops sharply, so that the deposited passivation layer can well protect the side wall and discharge the by-products. By changing the pulse frequency and duty cycle, the plasma parameters can be regulated, so that the reactive particles in the plasma are distributed more evenly, and finally the distribution of the plasma inside the groove is improved.

[0069] Compared with the continuous plasma etching method used in the traditional Bosch process, the pulsed plasma etching method used in the embodiment of the present application is to periodically turn on and off the bias power. In each pulse period, the time that the ions are in a high-energy state is relatively short, thereby reducing the cumulative damage to the surface of the substrate 100 material, and giving time for charge release, avoiding charge accumulation. Using helium with higher thermal conductivity as a protective gas can accelerate the uniform distribution of plasma and accelerate the removal of reaction products. Therefore, by adopting a pulsed plasma etching method protected by helium, the plasma distribution can be further optimized, charge release can be helped, etching damage can be reduced, and the anisotropy of etching can be optimized, avoiding the phenomenon that the groove in the formation is inclined to one side due to uneven lateral etching induction, thereby further reducing or avoiding the occurrence of groove tilt.

[0070] Furthermore, since helium is used as the carrier gas instead of traditional argon, and the bombardment force of helium is weaker, it can allow etching under relatively high bias power and low pressure. While enhancing the physical bombardment effect, improving the plasma directionality, and improving the groove inclination, it also effectively reduces the side wall damage and improves the reliability of the device.

[0071] It is worth noting that when etching is allowed at relatively high bias power and low pressure, the upper limit of the power that can be applied to the local corrected electric field (corresponding to 5% of the bias power) will also be increased, and the rate at which the plasma reaches the bottom of the groove will also be faster. This means that when improving the groove tilt at a larger angle, it will have a stronger control capability and effectively improve the etching efficiency.

[0072] In some embodiments, the etching is performed at a temperature of 10° C. to 60° C. For example, the temperature may be 10° C., 11° C., 15° C., 20° C., 25° C., 35° C., 42° C., 48° C., 53° C., 59° C., or 60° C., but is not limited thereto.

[0073] In some embodiments, during etching, the pressure is 1 mtorr to 100 mtorr. For example, the pressure may be 1 mtorr, 2 mtorr, 5 mtorr, 10 mtorr, 15 mtorr, 20 mtorr, 30 mtorr, 40 mtorr, 50 mtorr, 60 mtorr, 70 mtorr, 80 mtorr, 90 mtorr, 95 mtorr, 99 mtorr or 100 mtorr, etc., but is not limited thereto.

[0074] In some embodiments, when etching is performed, the source power is 100 W to 2000 W. For example, the source power may be 100 W, 150 W, 200 W, 300 W, 400 W, 500 W, 800 W, 1000 W, 1200 W, 1500 W, 1900 W or 2000 W, but is not limited thereto.

[0075] In some embodiments, during etching, the bias power is 10 W to 500 W. For example, the bias power may be 10 W, 15 W, 20 W, 40 W, 70 W, 100 W, 150 W, 200 W, 250 W, 300 W, 350 W, 400 W, 480 W or 500 W, but is not limited thereto.

[0076] An etching device according to an embodiment of the present application is described in detail below through a specific implementation manner and in combination with the accompanying drawings.

[0077] An etching device according to an embodiment of the present application can be used to implement a method for improving the morphology of a high aspect ratio etching structure according to an embodiment of the present application.

[0078] refer to Figure 4 , Figure 5 and Figure 6 An etching device according to an embodiment of the present application includes a chamber 10 , a gas storage module 22 , and a local correction electric field generating module 24 .

[0079] The chamber 10 is used to perform an etching process. A base 11 (eg, an electrostatic chuck) is disposed on the bottom of the chamber 10. The base 11 has a horizontal upper surface and is used to horizontally place a substrate 100 (eg, a silicon wafer) to be processed.

[0080] In some embodiments, a second electrode (bias electrode, not shown) is further disposed on the base 11 for applying bias power to the entire substrate 100. The second electrode is connected to a bias power source for applying bias power.

[0081] In some embodiments, a gas inlet 12 (eg, a gas nozzle) is disposed on the top of the chamber 10 for inputting a process gas for etching into the chamber 10 .

[0082] In some embodiments, an exhaust portion 13 (eg, an exhaust port) for exhausting gas is disposed on the bottom of the cavity 10 . The exhaust portion 13 is located on a side of the base 11 .

[0083] In some embodiments, the chamber 10 may be an inductively coupled plasma (ICP) etching chamber.

[0084] In some embodiments, the chamber 10 may be a capacitively coupled plasma (CCP) etch chamber.

[0085] The gas storage module 22 is disposed in the cavity 10. The gas storage module 22 has a first space 201, and the first space 201 is located above the base 11. A second space 202 is provided below the first space 201, and the base 11 is accommodated in the second space 202. The first space 201 and the second space 202 are communicatively isolated by the bottom 2011 of the first space.

[0086] The gas storage module 22 is used to form a plasma with a continuously increasing density in its first space 201, and the plasma is dispersed through the bottom 2011 of the first space and diffuses downward to the second space 202 under the natural effect of pressure, so that when it reaches the surface of the substrate 100 arranged on the base 11, a plasma with a uniform density is formed on the entire surface of the substrate 100, and then the surface of the substrate 100 is etched downward by the uniform plasma to form a plurality of grooves (high aspect ratio etching structure) distributed on the substrate 100.

[0087] In some embodiments, the gas storage module 22 includes an air flow dispersion plate 221. The air flow dispersion plate 221 is horizontally arranged above the base 11; and the side of the air flow dispersion plate 221 is sealed and connected to the side wall of the cavity 10, so that a relatively closed first space 201 and a second space 202 are formed in the cavity 10 on the upper and lower sides of the air flow dispersion plate 221. The side wall and the top wall of the cavity 10 used to enclose the first space 201, and the air flow dispersion plate 221 together constitute the gas storage module 22. The air inlet 12 is arranged on the top of the cavity 10, and the air inlet 12 is connected to the top of the first space 201. The air inlet 12 is used to introduce process gas into the first space 201 to further form a plasma of the process gas. The base 11 and the exhaust part 13 are both located in the second space 202.

[0088] In some embodiments, a radio frequency coil is provided on the upper portion of the chamber 10 for exciting the process gas input into the first space 201 to form plasma when started, and under the action of the bias power (bias voltage) and pressure applied by the second electrode, the formed plasma is dispersed by the air flow dispersion plate 221 and diffused downward to the surface of the substrate 100 placed on the base 11 to perform groove etching.

[0089] In some embodiments, a plurality of nanopores 222 (hollow parts) are provided on the surface of the air flow dispersion plate 221, so that the first space 201 and the second space 202 are isolated and connected through the nanopores 222 on the air flow dispersion plate 221 as the bottom 2011 of the first space. The nanopores 222 are used for the downward passage of plasma formed in the first space 201.

[0090] In some embodiments, the nanopores 222 on the surface of the airflow dispersion plate 221 are perpendicular to the surface of the horizontally disposed substrate 100. Moreover, the projection of any outermost nanopore 222 on the surface of the airflow dispersion plate 221 in the vertical direction is located outside the substrate 100. In this way, it is ensured that the plasma airflow diffused from the airflow dispersion plate 221 to the surface of the substrate 100 can cover the entire surface of the substrate 100.

[0091] In some embodiments, when the substrate 100 is horizontally disposed on the base 11, the center of the airflow dispersion plate 221 is aligned (or substantially aligned) with the center of the substrate 100. The arrangement of the nanopores 222 on the surface of the airflow dispersion plate 221 is as follows: in the direction from the center to the edge of the substrate 100, the nanopores 222 are distributed from sparse to dense on the surface of the airflow dispersion plate 221, so that the plasma in the first space 201 passes through the airflow dispersion plate 221, is vertically dispersed by the nanopores 222 into multiple plasma airflows from sparse to dense, and diffuses downward toward the surface of the substrate 100.

[0092] In some embodiments, the nanopores 222 are preferably circular holes.

[0093] In some embodiments, at various positions on the surface of the airflow dispersion plate 221, the apertures of the nanopores 222 are consistent. In this case, the number of nanopores 222 gradually increases in the direction from the center to the edge of the surface of the airflow dispersion plate 221 (i.e., in the direction from the center to the edge of the surface of the substrate 100). In other words, in the direction from the center to the edge of the surface of the airflow dispersion plate 221, the pore occupancy of the nanopores 222 (the area ratio of the nanopores 222 per unit area on the surface of the airflow dispersion plate 221) gradually increases.

[0094] In some embodiments, at various positions on the surface of the airflow dispersion plate 221, the apertures of the nanopores 222 are consistent, and the apertures of the nanopores 222 are 1nm to 100nm. For example, the apertures of the nanopores 222 can be 1nm, 2nm, 5nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 98nm, 99nm or 100nm, but are not limited thereto. In addition, the pore occupancy of the nanopores 222 on the airflow dispersion plate 221 is gradually increased from 10% to 50% along the center to the edge direction of the substrate 100. For example, in the area closest to the center of the airflow dispersion plate 221, the pore occupancy of the nanopores 222 is 10%, in the area farthest from the center of the airflow dispersion plate 221, the pore occupancy of the nanopores 222 is 50%, and in other areas between the above two areas, the pore occupancy of the nanopores 222 gradually increases within a range from greater than 10% to less than 50%.

[0095] Furthermore, the pore occupancy of the nanopores 222 on the airflow dispersion plate 221 gradually increases from the center to the edge of the substrate 100 between 10% and 45%, 10% to 40%, 10% to 35%, 10% to 30%, 15% to 50%, 15% to 45%, 15% to 40%, 15% to 35%, 20% to 50%, 20% to 45%, 20% to 40%, 25% to 50%, 25% to 45% or 30% to 50%, but is not limited to this.

[0096] In some embodiments, the arrangement of each nanopore 222 is as follows: in the direction from the center to the edge of the substrate 100 (in the direction from the center to the edge of the surface of the airflow dispersion plate 221), the aperture of each nanopore 222 is distributed from small to large, so that the plasma is vertically dispersed by each nanopore 222 on the airflow dispersion plate 221 into multiple plasma airflows with diameters from small to large, and diffused downward into the second space 202. In this case, the number of nanopores 222 gradually increases in the direction from the center to the edge of the airflow dispersion plate 221. Alternatively, in the direction from the center to the edge of the airflow dispersion plate 221, the hole occupancy of the nanopore 222 gradually increases.

[0097] In some embodiments, the aperture of each nanopore 222 gradually increases from 1 nm to 100 nm along the center to edge direction of the surface of the airflow dispersion plate 221. For example, in the area closest to the center of the airflow dispersion plate 221, the aperture of the nanopore 222 is 1 nm, and in the area farthest from the center of the airflow dispersion plate 221, the aperture of the nanopore 222 is 100 nm, and in other areas between the above two areas, the aperture of the nanopore 222 gradually increases within the range of greater than 1 nm to less than 100 nm. In addition, along the center to edge direction of the airflow dispersion plate 221, the pore occupancy of the nanopore 222 gradually increases between 10% and 50%.

[0098] Furthermore, the aperture of each nanopore 222 gradually increases from the center to the edge of the surface of the airflow dispersion plate 221 between 2nm and 95nm, 3nm and 90nm, 4nm and 85nm, 5nm and 80nm, 6nm and 75nm, 7nm and 70nm, 8nm and 65nm, 9nm and 60nm or 10nm and 55nm, but is not limited thereto.

[0099] In some embodiments, the distance (first distance) between the air inlet 12 and the surface of the substrate 100 when disposed on the base 11 is 100 mm to 200 mm. For example, the first distance is 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, 195 mm or 200 mm, but is not limited thereto.

[0100] In some embodiments, the distance (second distance) between the air flow distribution plate 221 and the surface of the substrate 100 when disposed on the base 11 is 20 mm to 60 mm. For example, the second distance is 20 mm, 21 mm, 22 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 58 mm, 59 mm or 60 mm, but is not limited thereto.

[0101] When the first distance and the second distance are specifically set, it is a necessary condition to avoid turbulence when the process gas reaches the surface of the substrate 100 .

[0102] In some embodiments, the air flow dispersion plate 221 is made of an insulating material with stable chemical properties in the etching chamber 10, so that the plasma is not grounded when passing through the air flow dispersion plate 221. For example, the material of the air flow dispersion plate 221 includes silicon oxide, silicon nitride, aluminum oxide or aluminum nitride, but is not limited thereto.

[0103] Therefore, when the plasma in the first space 201 diffuses downward to the surface of the substrate 100 through the nanopores 222 on the airflow dispersion plate 221 under the action of pressure, the amount of airflow arriving at the edge can be made consistent with the amount of airflow arriving at the center, and the density of the airflow from the center to the edge of the substrate 100 surface can also be made consistent, such as Figure 6 As shown by the downward hollow arrow in FIG. , when the plasma contacts the surface of the substrate 100 , the plasma is evenly distributed on the surface of the substrate 100 , thereby improving the process uniformity.

[0104] The local correction electric field generating module 24 is disposed on the base 11. The local correction electric field generating module 24 is used to apply the generated additional local correction electric field to the target improvement area on the substrate 100 according to the acquired groove inclination occurrence area and groove inclination size data during the etching process, and adjust the electric field strength of the local correction electric field to a preset value.

[0105] refer to Figure 4 and Figure 5 In some embodiments, the surface of the substrate 100 includes a central region A and an edge region B surrounding the central region A, and the target improvement region is located in the edge region B. The local correction electric field generating module 24 includes a plurality of independently arranged first electrodes 241. The arrangement position of each first electrode 241 on the base 11 is located on the edge region B, and is evenly arranged around the central region A. An alternating voltage is applied to the first electrode 241 corresponding to the position of the target improvement region to generate a local correction electric field.

[0106] It should be noted that the first electrodes 241 and the first electrodes 241 and the second electrodes are electrically insulated from each other and no electrical interconnection is generated.

[0107] In some embodiments, each first electrode 241 is connected to a dedicated power source, which is used to apply an alternating voltage to the first electrode 241 corresponding to the target improvement area to generate a local correction electric field.

[0108] The dedicated power supply may be a power supply independently provided outside the etching device, or the dedicated power supply may be established based on a bias power supply provided in the etching device itself.

[0109] In some embodiments, when the preset value of the electric field strength is reached, the power applied by the dedicated power supply to the first electrode 241 is 1% to 5% of the bias power applied by the bias power supply, and the preset value is proportional to the groove inclination.

[0110] In some embodiments, the number of first electrodes 241 is 4 to 16 and is evenly distributed around the central area A. For example, the number of first electrodes 241 may be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16.

[0111] In this embodiment, the number of the first electrodes 241 is 8. The first electrodes 241 are in the shape of a sector block, and each first electrode 241 is disposed on the bottom of the base 11 in a manner such that its sector ends are adjacent to each other, forming a discontinuous circular ring. Figure 5 shown.

[0112] In some embodiments, the etching equipment is used to perform a pulsed plasma etching process using helium protection.

[0113] In some embodiments, a control module is provided to control the dedicated power supply so as to control the on and off of the dedicated power supply and the power applied to the first electrode 241 .

[0114] In some embodiments, the control module is disposed in a control system of the etching device. Alternatively, the control module is a control system of the etching device.

[0115] In some embodiments, the control system of the etching equipment includes a host computer and / or a slave computer.

[0116] Therefore, the embodiment of the present application sets a gas storage module 22 in the cavity 10, firstly increases and homogenizes the density of the plasma formed in the first space 201 by pressurizing the gas storage, and then disperses the plasma and diffuses downward to the second space 202 through the gas flow dispersion plate 221 with nanopores 222, so as to achieve uniform distribution of the plasma on the entire surface of the substrate 100; further, by adding a local correction electric field generating module 24 corresponding to the edge area B of the substrate 100 on the base 11, and including a plurality of first electrodes 241, to construct an electrostatic field with adjustable area and adjustable intensity, better etching in the depth direction can be achieved through the locally applied correction electric field, so the rate will also be faster, and a higher etching rate and stronger anisotropy can be exerted, which is conducive to high aspect ratio etching and improves the process window. In addition, by using helium with weaker bombardment force instead of traditional argon as a carrier gas, etching can be allowed at relatively high bias power and low pressure, which enhances the physical bombardment effect, improves the plasma directionality, and improves the etching efficiency. Thus, by effectively improving the abnormal morphology of the etching tilt produced on the substrate 100, the electrical performance and mechanical reliability of the groove are guaranteed, thereby improving the yield and stability of the device.

[0117] Figure 8 The results show that the grooves are tilted according to known conditions (e.g. Figure 7 The vertical morphology of the groove on the substrate obtained by improving the morphology of the high aspect ratio etching structure (or etching equipment) according to the embodiment of the present application ( Figure 8 Mark 1 indicates that the depth in the Y direction is 1.4086 microns, mark 2 indicates that the top width in the X direction is 1.9808 microns, and mark 3 indicates that the bottom width in the X direction is 1.9864 microns). Figure 8 It can be seen that after improvement, the groove shows a better morphology with an inclination angle approaching 0 degrees, indicating that Figure 7 The embodiment of the present application has a significant effect of improving the inclination degree of the groove.

[0118] The embodiment of the present application also provides a semiconductor structure, which includes a substrate and a plurality of grooves (high aspect ratio etching structures) distributed on the substrate. The grooves are made using the high aspect ratio etching structure morphology improvement method provided in the above embodiment to reduce the inclination on the substrate. Alternatively, the grooves are made using the etching equipment provided in the above embodiment to reduce the inclination on the substrate.

[0119] In some embodiments, a semiconductor structure provided by embodiments of the present application can be applied to the field of three-dimensional advanced packaging, and utilizes trenches formed on a substrate as through silicon via (TSV) vertical interconnect structures on 3D integrated circuit chips.

[0120] In other aspects, the embodiments of the present application further provide an electronic device, including the semiconductor structure of the embodiments of the present application. The electronic device may be a storage device, a mobile phone, a computer, a tablet computer, a television, an artificial intelligence device, etc.

[0121] In summary, the embodiment of the present application utilizes the pressure effect to first pressurize and store the plasma formed in the first space 201, so that the density of the plasma continues to increase, and then, under the natural effect of pressure, the plasma is dispersed through the bottom 2011 of the first space and diffuses downward to the second space 202, so as to form a plasma with a uniform density on the entire surface of the substrate 100, thereby achieving uniform distribution of the process gas (plasma) on the entire surface of the substrate 100, and in the process of trench etching, according to the acquired data on the occurrence area of ​​the trench tilt and the size of the trench tilt, by An additional local correction electric field is applied to the target improvement area on the substrate 100, and the electric field strength of the local correction electric field is adjusted to a preset value, an electrostatic field with adjustable area and adjustable strength is constructed, and anisotropic etching is strengthened, thereby optimizing the gas field and local electric field during the groove etching process, effectively solving the abnormal morphology of etching tilt from the middle to the edge of the substrate and different areas of the edge caused by the uneven distribution of the gas field and the electromagnetic field in the past, and being able to exert a higher etching rate and a stronger anisotropic effect, which is conducive to high aspect ratio etching and improves the process window. Therefore, by achieving effective improvement of the abnormal morphology of etching tilt, the electrical performance and mechanical reliability of the groove are guaranteed, thereby improving the yield and stability of the device. In addition, the embodiment of the present application can also improve the problems of uneven edge etching, grass at the bottom of the edge groove, and missing mask on the edge, and has a comprehensive improvement effect.

[0122] The above are only preferred embodiments of the present application, and the embodiments are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made using the description and drawings of the present application should be included in the protection scope of the present application.

Claims

1. A method for improving the morphology of a high aspect ratio etching structure, characterized in that: include: forming a plasma with a continuously increasing density in the first space; The plasma is dispersed through the bottom of the first space and diffused downward into the second space under the natural effect of pressure, so that when the plasma reaches the surface of the substrate located in the second space, the plasma with a uniform density is formed on the entire surface of the substrate; The surface of the substrate is etched downward by the plasma to form a plurality of high aspect ratio etching structures distributed on the substrate, and during the etching process, an additional local correction electric field is applied to the target improvement area on the substrate according to the acquired data on the tilt occurrence area and tilt size of the high aspect ratio etching structure, and the electric field strength of the local correction electric field is adjusted to a preset value.

2. The method for improving the morphology of a high aspect ratio etching structure according to claim 1, characterized in that: In the direction from the center to the edge of the substrate, the plasma is vertically dispersed at the bottom of the first space into multiple plasma gas flows from sparse to dense, and diffused downward into the second space, and / or the plasma is vertically dispersed at the bottom of the first space into multiple plasma gas flows from small to large diameters, and diffused downward into the second space.

3. The method for improving the morphology of a high aspect ratio etching structure according to claim 1, characterized in that: A central area and an edge area surrounding the central area are defined on the surface of the substrate, the target improvement area is located in the edge area, the local correction electric field is applied to the edge area, and a plurality of application areas of the local correction electric field are configured around the central area.

4. The method for improving the morphology of a high aspect ratio etching structure according to claim 3, characterized in that: The local correction electric field is generated by applying an alternating voltage, and the power required to be applied to the local correction electric field to reach the preset value is 1% to 5% of the bias power applied to the substrate as a whole, and the preset value is proportional to the size of the inclination; and / or the number of application areas of the local correction electric field is evenly distributed 4 to 16.

5. The method for improving the morphology of a high aspect ratio etching structure according to claim 1, characterized in that: The etching is performed based on a modified Bosch process, which is a pulsed plasma etching process using helium protection; and / or, during etching, the temperature is 10°C to 60°C, the pressure is 1mtorr to 100mtorr, the source power is 100W to 2000W, and the bias power is 10W to 500W.

6. An etching device, characterized in that: include: A cavity, wherein a base is provided on the bottom of the cavity, and a substrate is provided on the base; a gas storage module, arranged in the cavity, the gas storage module having a first space, the first space being located above the pedestal, a second space being located below the first space, the pedestal being accommodated in the second space, the gas storage module being used to form a plasma with a continuously increasing density in the first space, and to disperse the plasma through the bottom of the first space and diffuse downward into the second space under the natural effect of pressure, so that when the plasma reaches the surface of the substrate arranged on the pedestal, the plasma with a uniform density is formed on the entire surface of the substrate, and then the surface of the substrate is etched downward by the plasma to form a plurality of high aspect ratio etching structures distributed on the substrate; A local correction electric field generating module is arranged on the base. The local correction electric field generating module is used to apply the generated additional local correction electric field to the target improvement area on the substrate during the etching process according to the obtained data on the tilt occurrence area and tilt size of the high aspect ratio etching structure, and adjust the electric field strength of the local correction electric field to a preset value.

7. The etching device according to claim 6, characterized in that: The gas storage module comprises an airflow dispersion plate, which is horizontally arranged above the base, and the side of the airflow dispersion plate is in close contact with the side wall of the cavity, and the first space and the second space are respectively formed in the cavity on the upper and lower sides of the airflow dispersion plate, and a plurality of nanopores are arranged on the surface of the airflow dispersion plate, and the nanopores are perpendicular to the surface of the horizontally arranged substrate, and the nanopores are used to pass the plasma, and the arrangement form of each of the nanopores is: in the direction from the center to the edge of the substrate, each of the nanopores is distributed from sparse to dense, and / or the aperture of each of the nanopores is distributed from small to large; And / or, the local correction electric field generating module includes a plurality of independently arranged first electrodes, the surface of the substrate includes a central area and an edge area surrounding the central area, the target improvement area is located in the edge area, the arrangement position of each of the first electrodes on the base is located on the edge area, and is evenly arranged around the central area, and the local correction electric field is generated by applying an alternating voltage to the first electrodes corresponding to the positions of the target improvement areas; And / or, the etching equipment is used to perform a pulsed plasma etching process using helium protection.

8. The etching device according to claim 7, characterized in that: The air flow dispersion plate is made of insulating material; and / or, an air inlet is provided on the top of the cavity, and the air inlet is connected to the top of the first space, the air inlet is used to introduce process gas into the first space to form the plasma, the first distance between the air inlet and the surface of the substrate when set is 100mm~200mm, and the second distance between the air flow dispersion plate and the surface of the substrate when set is 20mm~60mm; and / or, the pore occupancy of the nanopores on the air flow dispersion plate is gradually increased from 10% to 50% along the center to the edge direction of the substrate; and / or, the pore size of the nanopores is gradually increased from 1nm to 100nm along the center to the edge direction of the substrate.

9. The etching device according to claim 7, characterized in that: A second electrode is also provided on the base, which is used to apply bias power to the entire substrate. The power required to be applied to the first electrode when the preset value is reached is 1% to 5% of the applied bias power, and the preset value is proportional to the size of the inclination; and / or the number of the first electrodes is 4 to 16.

10. A semiconductor structure comprising a substrate and a plurality of high aspect ratio etched structures distributed on the substrate, characterized in that: The high aspect ratio etching structure is manufactured using the high aspect ratio etching structure morphology improvement method described in any one of claims 1 to 5 or the etching equipment described in any one of claims 6 to 9.

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