A substrate etching method and etching structure

Abstract

The application discloses a substrate etching method and an etching structure, and comprises the following steps: forming an organic mask on the surface of a substrate; performing an etching process to etch the exposed substrate surface and form a high aspect ratio etching structure; the etching process comprises periodically cyclic etching steps formed by a first etching step and a second etching step; the first etching step uses neutral particles in the plasma of a first gas (including a fluorine-containing gas) to perform isotropic first etching on the substrate, and forms a polymer layer on the inner wall of the forming high aspect ratio etching structure and the surface of the organic mask to protect the substrate during the first etching; the second etching step uses charged particles in the plasma of a second gas (including an inert gas) to perform anisotropic second etching on the polymer layer on the bottom of the inner wall, and expose the underlying substrate to perform the first etching again. The application can simplify the process, improve the selection ratio and improve the efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor processing, in particular to a substrate etching method and etching structure. BACKGROUND

[0002] At present, the dry etching process applied to through glass via (TGV) processing usually uses fluorine-containing plasma to etch the glass substrate. Since the selectivity ratio of the photoresist used as the mask material to the glass substrate (SiO2) is not enough, a metal is used as the hard mask material to perform subsequent TGV etching. However, the process maturity of the current TGV etching process using metal as the hard mask material is still relatively low (relative to TSV (through silicon via) etching), and the actual steps in the application are relatively complex, and the cost is relatively high. At the same time, using a metal mask can also cause byproduct pollution problems. In addition, the existing TGV etching process usually adopts a non-periodic cyclic etching mode of one-step etching (relative to a periodic cyclic etching mode of deposition-etching-deposition-etching repetition), and the size uniformity is relatively poor, which has been difficult to meet the growing demand for larger aspect ratio and higher interconnection density. Therefore, it is necessary to study a process method which can significantly improve the above problems. SUMMARY

[0003] The present application aims to overcome the above problems existing in the prior art, and provides a substrate etching method and etching structure to avoid using a metal mask, simplify the process, and improve the selectivity ratio of the organic mask to facilitate the etching of a high aspect ratio etching structure and improve the efficiency.

[0004] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0005] According to the first aspect of the present application, the embodiments of the present application provide a substrate etching method, comprising:

[0006] providing a substrate;

[0007] forming a plurality of organic masks on the surface of the substrate, and the first opening is formed between two adjacent organic masks;

[0008] performing an etching process to etch the surface of the substrate exposed in the first opening, and forming a high aspect ratio etching structure on the substrate;

[0009] wherein the etching process comprises a plurality of periodic cyclic etching steps formed in turn according to a first etching step and a second etching step;

[0010] The first etching step uses neutral particles in a plasma of a first gas to perform an isotropic first etching of the substrate and to form a polymer layer on inner walls of the high aspect ratio etching structure being formed and on exposed surfaces of the organic mask to protect the inner walls and the organic mask from the first etching;

[0011] The second etching step uses charged particles in a plasma of a second gas to perform an anisotropic second etching of the polymer layer on the inner wall bottom to form a second opening in the polymer layer on the bottom to expose the substrate for the first etching to be performed again through the second opening;

[0012] The first gas comprises a fluorine-containing gas and the second gas comprises an inert gas.

[0013] In some embodiments, the neutral particles are obtained by performing ion filtering to filter out ions contained in a plasma formed by the first gas being introduced.

[0014] In some embodiments, the charged particles are obtained by not performing ion filtering to allow ions contained in a plasma formed by the second gas being introduced to be retained.

[0015] In some embodiments, the substrate comprises a glass substrate.

[0016] In some embodiments, the first gas comprises a fluorocarbon gas having a fluorine-to-carbon ratio greater than or equal to 1:3.

[0017] In some embodiments, the glass substrate comprises a SiO2 substrate.

[0018] In some embodiments, the first gas comprises at least one of C4F8, C4F6, C5F8, CHF3, and CH2F2.

[0019] In some embodiments, the organic mask comprises a photoresist mask.

[0020] In some embodiments, the second gas comprises Ar.

[0021] In some embodiments, the first etching step is performed using a first temperature, a first pressure, and a first bias power, and the second etching step is performed using a second temperature, a second pressure, and a second bias power, the first temperature and the second temperature being greater than 0°C, the first pressure being greater than the second pressure, and the first bias power being less than the second bias power.

[0022] In some embodiments, the first temperature is in a range from 50°C to 90°C.

[0023] In some embodiments, the first pressure is 100 mTorr to 10 Torr.

[0024] In some embodiments, the first bias power is 0 W.

[0025] In some embodiments, the second temperature is 50°C to 90°C.

[0026] In some embodiments, the second pressure is 10 mTorr to 100 mTorr.

[0027] In some embodiments, the second bias power is 50 W to 100 W.

[0028] In some embodiments, another implementation is that the inert gas in the second gas is replaced by a chlorine-containing gas.

[0029] In some embodiments, another implementation is that the second gas comprises the inert gas and a chlorine-containing gas.

[0030] In some embodiments, the chlorine-containing gas comprises BCl3.

[0031] According to a second aspect of the present application, the embodiments of the present application further provide an etching structure obtained by using the substrate etching method provided by any one of the embodiments of the first aspect.

[0032] The embodiments of the present application can / at least have the following advantages:

[0033] (1) By using the organic mask and the etching process comprising the multiple periodic and cyclic etching steps formed in sequence by the first etching step and the second etching step, the substrate is etched, the neutral particles in the plasma of the first gas (comprising the fluorine-containing gas) are used to perform the isotropic first etching on the substrate, the polymer layer protecting the inner wall of the etching structure and the organic mask is formed, and the charged particles in the plasma of the second gas (comprising the inert gas) are used to perform the anisotropic second etching on the polymer layer on the bottom of the inner wall, so that the underlying substrate is exposed for the first etching again, thereby significantly improving the selectivity of the organic mask, realizing the formation of the high aspect ratio etching structure on the substrate by using the organic mask to replace the traditional metal hard mask, improving the etching uniformity and perpendicularity, avoiding the pollution problem when using the metal mask, simplifying the process, and improving the efficiency.

[0034] (2) By using neutral particles in the plasma of the first gas containing fluorine gas to isotropically etch the substrate (first etching) in each cycle and turning off the bias power (the first bias power is 0 W), the bombardment on the organic mask (such as a photoresist mask) can be reduced, and the polymer layer formed on the organic mask can be used to protect the organic mask while etching, which significantly improves the selectivity of the organic mask and forms an etching structure with a certain depth on the substrate. Then, under a certain bias power (the second bias power is 50 W-100 W), charged particles in the plasma of the second gas containing inert gas are used to anisotropically etch (second etching), which can open a new etching window (second opening). Therefore, by performing the first etching again, the etching can continue downward, thus eliminating the problem of difficult continuous downward etching caused by the previous isotropic etching. By repeatedly performing the periodic cycle etching step, a high aspect ratio etching structure that is difficult to achieve by conventional processes can be finally achieved on the glass substrate.

[0035] (3) By using a fluorocarbon gas with a fluorocarbon ratio greater than or equal to 1:3 as the first gas for the first etching, the high fluorocarbon ratio can be used to enhance polymer formation. A polymer layer is formed on the inner wall of the forming high aspect ratio etching structure and the exposed surface of the organic mask during etching, thereby playing a dual role of etching and protection. Not only can the degree of lateral etching be controlled, but the separate and indispensable deposition step in the traditional periodic cycle etching process can also be omitted. Therefore, only one set of process gas (first gas) system is needed to complete the etching and deposition processes that originally required two sets of process gas (etching gas + deposition gas) systems, greatly simplifying the process, improving efficiency, and reducing control difficulty.

[0036] (4) By using Ar as the second gas for the second etching, the inner wall bottom of the forming high aspect ratio etching structure can be directionally bombarded to remove the polymer layer on the inner wall bottom, exposing the underlying substrate for the first etching again. Meanwhile, Ar has the characteristic of not having a significant etching effect on the substrate (relative to conventional etching gases such as fluorine-containing gases), which can avoid damaging the formed etching morphology and prevent the problem of increasing the size of the upper part with repeated etching. This ensures etching uniformity and perpendicularity, thereby facilitating the realization of higher aspect ratio and higher interconnection density etching structures on the glass substrate that are difficult to achieve by conventional processes.

[0037] Other advantages of the present application will be described in the specific embodiments below. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1This is a flowchart of a substrate etching method according to a preferred embodiment of this application.

[0039] Figure 2 This is a schematic diagram of the structure of an organic mask with a first opening between adjacent parts, provided as a preferred embodiment of the present application.

[0040] Figure 3 This is a schematic diagram of a structure after the first intermediate etched structure is formed on a substrate, according to a preferred embodiment of this application.

[0041] Figure 4 This is a schematic diagram of a structure after a second opening is formed on the bottom of a first intermediate etched structure, according to a preferred embodiment of this application.

[0042] Figure 5 This is a schematic diagram of a structure after a second intermediate etching structure is formed below the second opening, according to a preferred embodiment of this application.

[0043] Figure 6 This is a schematic diagram of a high aspect ratio etched structure formed on a substrate, according to a preferred embodiment of this application.

[0044] Figure 7 A preferred embodiment of this application provides a method in Figure 6 A schematic diagram of the structure after removing the organic mask based on the original structure.

[0045] Figure 8 A preferred embodiment of this application provides a method for... Figure 6 A schematic diagram of the high aspect ratio etched structure after sidewall treatment.

[0046] Figure 9 A preferred embodiment of this application provides a method in Figure 8 A schematic diagram of the structure after removing the organic mask based on the original structure.

[0047] In the figure: 10. Substrate; 11. First opening; 12. Organic mask; 13. Intermediate etched structure; 14. Polymer layer; 15. Second opening; 16. High aspect ratio etched structure. Detailed Implementation

[0048] The existing glass through via (TGV) etching process usually uses plasma of fluorine-containing gas such as CF4 and SF6 to perform non-periodic cyclic etching on a glass substrate. Since one-step continuous etching is performed by using a polymer-forming gas with relatively light polymer-forming property such as CF4 or SF6, the selectivity of photoresist is low (main reasons: firstly, such gas cannot provide sufficient polymer to protect photoresist, and secondly, ions contained in the plasma have energy and can cause a large degree of bombardment on photoresist), and it is difficult to etch a deep TGV structure. If a polymer-forming gas with relatively heavy polymer-forming property such as C4F8 and C4F6 is used, although it can provide good protection for photoresist, too much polymer formed in the non-periodic cyclic etching process can cause the etching angle to deviate, and even cause the problem of "etching stop". Therefore, from the perspective of ensuring etching, the existing TGV etching process can only use a polymer-forming gas with relatively light polymer-forming property, but this brings the problem of low photoresist selectivity, and therefore a metal mask with higher etching resistance is used for TGV etching. The one-step continuous etching has the disadvantage that the size uniformity of the etched TGV is relatively poor (generally a large upper and small lower morphology is formed), which affects the realization of the limit high aspect ratio etching, and thus it is difficult to meet the increasing demand for larger aspect ratio and higher interconnection density.

[0049] To solve the problems in the prior art, the embodiments of the present application provide a substrate etching method, which comprises:

[0050] providing a substrate;

[0051] forming a plurality of organic masks on the surface of the substrate, and a first opening between two adjacent organic masks;

[0052] performing an etching process to etch the surface of the substrate exposed in the first opening, and forming a high aspect ratio etching structure on the substrate;

[0053] wherein the etching process comprises a plurality of periodic cyclic etching steps formed in sequence by a first etching step and a second etching step;

[0054] the first etching step uses neutral particles in plasma of a first gas to perform isotropic first etching on the substrate, and forms a polymer layer on the inner wall of the high aspect ratio etching structure being formed and the exposed surface of the organic mask, so as to protect the inner wall and the organic mask during the first etching;

[0055] The second etching step uses charged particles in a plasma of a second gas to perform an anisotropic second etching on the polymer layer on the bottom of the inner wall, to form a second opening on the polymer layer on the bottom, to expose the substrate, so as to perform the first etching again through the second opening.

[0056] The first gas comprises a fluorine-containing gas, and the second gas comprises an inert gas.

[0057] The embodiments of the present application perform etching on a substrate by using an organic mask and an etching process comprising a plurality of periodically cyclic etching steps formed in sequence by a first etching step and a second etching step, perform an isotropic first etching on the substrate by using neutral particles in a plasma of a first gas (comprising a fluorine-containing gas), form a polymer layer which protects the inner wall of the etching structure and the organic mask, and perform an anisotropic second etching on the polymer layer on the bottom of the inner wall by using charged particles in a plasma of a second gas (comprising an inert gas), to expose the substrate below, so as to perform the first etching again, thereby significantly improving the selectivity of the organic mask, realizing the formation of a high aspect ratio etching structure on the substrate by using the organic mask to replace the traditional metal hard mask, improving the etching uniformity and perpendicularity, avoiding the pollution problem when using the metal mask, simplifying the process, and improving the efficiency.

[0058] The embodiments of the present application also provide an etching structure obtained by using the above-mentioned substrate etching method.

[0059] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0060] Reference Figure 1 The embodiments of the present application provide a substrate etching method, which comprises the following steps in sequence:

[0061] Step S11: providing a substrate.

[0062] Reference Figure 2 In some embodiments, a glass substrate can be used as the substrate 10, so as to further form a required high aspect ratio etching structure on the substrate 10 by performing the etching process. The material of the substrate 10 is not limited in the present application.

[0063] In some embodiments, the glass substrate comprises a SiO2 substrate and the like.

[0064] In some embodiments, the high aspect ratio etching structure can be a glass through via (TGV) or a deep trench and the like.

[0065] Step S12: forming a plurality of organic masks on the surface of the substrate.

[0066] Reference Figure 2In some embodiments, an organic mask layer is formed on the upper surface of the substrate 10, and the organic mask layer is patterned to form a plurality of patterned organic masks 12 on the upper surface of the substrate 10. Any two adjacent organic masks 12 have a first opening 11 as an etching window, and the surface of the substrate 10 between the two adjacent organic masks 12 is exposed at the bottom of the first opening 11.

[0067] It should be noted that, Figure 2 In the above embodiment, only the case where two organic masks 12 are formed on the upper surface of the substrate 10 is described. However, it should be understood that more organic masks can be formed on the upper surface of the substrate 10, such as three organic masks, four organic masks, ten organic masks, and the like, and the number of organic masks is not limited to the above.

[0068] In some embodiments, the organic material includes photoresist. That is, the organic mask layer includes a photoresist layer, and the organic mask 12 includes a photoresist mask.

[0069] In some embodiments, a spin coating process is used to form a photoresist layer on the upper surface of the substrate 10. Then, a photolithography process is used to perform photolithography on the photoresist layer, thereby forming a plurality of photoresist patterns, i.e., organic masks 12, on the upper surface of the substrate 10.

[0070] Step S13: Perform isotropic first etching on the substrate to form an intermediate etching structure on the substrate, and form a polymer layer on the inner wall of the intermediate etching structure and the exposed surface of the organic mask.

[0071] In some embodiments, by performing the etching process and taking the organic mask 12 as a mask, the surface of the substrate 10 exposed in the first opening 11 between the adjacent organic masks 12 is periodically and cyclically etched to form a high aspect ratio etching structure on the substrate 10.

[0072] The etching process includes a plurality of periodically and cyclically etching steps formed in sequence by the first etching step and the second etching step. The first etching step is used to perform first etching on the substrate 10, and form a polymer layer on the inner wall of the high aspect ratio etching structure being formed and the entire exposed surface of the organic mask 12, so as to protect the inner wall of the high aspect ratio etching structure being formed and the organic mask 12 during the first etching.

[0073] Therefore, in the etching process of the above embodiment, the deposition step provided in the conventional periodically and cyclically etching process is no longer provided independently.

[0074] Reference Figure 3In some embodiments, a first etching step in the etching process is performed, using neutral particles in the plasma of a first gas, with an organic mask 12 as a mask, and through a first opening 11, isotropically etching the substrate 10 to form an intermediate etched structure 13 (the first intermediate etched structure 13) on the substrate 10. Simultaneously, taking advantage of the high polymer-forming properties of the first gas, a polymer layer 14 is formed on the inner wall of the intermediate etched structure 13 (the high aspect ratio etched structure in formation) and on all exposed surfaces of the organic mask 12 (for emphasis, ...). Figure 3 Only the polymer layer 14 located on the inner wall of the intermediate etched structure 13 and the top surface of the organic mask 12 is shown. Polymer layers 14 deposited on other parts (such as the sides of the organic mask 12 and the exposed bottom surface at the junction with the top of the intermediate etched structure 13) are omitted from the display. This is to protect the inner wall of the intermediate etched structure 13 and the organic mask 12 during the first etching step. In other words, in this embodiment, the first gas used in the first etching step is used both to etch the substrate 10 to form the intermediate etched structure 13 and to form the polymer layer 14 to protect the inner wall of the intermediate etched structure 13 and the organic mask 12.

[0075] By ionizing the first gas introduced into the process chamber, a plasma of the first gas is obtained. The ion filtration function of the process chamber is then activated to remove charged particles such as ions from the plasma formed by the first gas, resulting in neutral particles. These neutral particles from the plasma are then used to perform an isotropic first etching on the substrate 10, forming a first intermediate etching structure 13 on the substrate 10. Simultaneously, a polymer layer 14 is formed on the inner wall of the intermediate etching structure 13 and on the surface of the organic mask 12.

[0076] In some embodiments, the first gas includes a fluorine-containing gas.

[0077] In some embodiments, the first gas comprises a fluorocarbon gas with a carbon-to-fluorine ratio greater than or equal to 1:3. For example, the first gas comprises at least one of C4F8, C4F6, C5F8, CHF3, and CH2F2, and He may be used as an auxiliary gas.

[0078] In some embodiments, the first gas is any one of C4F8, C4F6, C5F8, CHF3, and CH2F2, and He can be used as an auxiliary gas.

[0079] In some embodiments, the first etching step is performed using a first temperature, a first pressure, a first source power, and a first bias power. The first temperature is greater than 0°C, the first pressure is greater than a pressure (second pressure) used in performing the second etching step, and the first source power is greater than a source power (second source power) used in performing the second etching step, and the first bias power is less than a bias power (second bias power) used in performing the second etching step.

[0080] In some embodiments, the first temperature is 50°C to 90°C. For example, the first temperature can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, or 90°C, or any value between any two of the foregoing. However, the present application is not limited thereto.

[0081] In some embodiments, the first pressure is 100 mTorr to 10 Torr. For example, the first pressure can be 100 mTorr, 200 mTorr, 500 mTorr, 800 mTorr, 1 Torr, 2 Torr, 5 Torr, 8 Torr, or 10 Torr, or any value between any two of the foregoing. However, the present application is not limited thereto.

[0082] In some embodiments, the first source power is 1000 W to 3000 W. For example, the first source power can be 1000 W, 1200 W, 1500 W, 2000 W, 2500 W, or 3000 W, or any value between any two of the foregoing. However, the present application is not limited thereto.

[0083] In some embodiments, the first bias power is 0 W (bias power is turned off).

[0084] In some embodiments, the total flow rate of the first gas (including fluorocarbon gas and He) is 50 sccm to 1000 sccm. For example, the total flow rate of the first gas can be 50 sccm, 60 sccm, 80 sccm, 100 sccm, 300 sccm, 500 sccm, 700 sccm, or 1000 sccm, or any value between any two of the foregoing. However, the present application is not limited thereto.

[0085] In some embodiments, when the first gas includes any one of C4F8, C4F6, C5F8, CHF3, CH2F2, and He is used as an auxiliary gas, the following flow rate ratio relationship can be obtained:

[0086] C4F8:He = 3:1 to 4:1; C4F6:He = 5:1 to 6:1; C5F8:He = 5:1 to 6:1; CHF3:He = 1:1 to 2:1; CH2F2:He = 2:1 to 3:1. However, the present application is not limited thereto.

[0087] The embodiment of the present application can reduce the bombardment of the organic mask 12 (photoresist mask) by using the neutral particles (fluorine radicals) in the plasma of the fluorocarbon gas with a fluorocarbon ratio greater than or equal to 1:3 to perform the isotropic etching (first etching) on the substrate 10, and can enhance the polymer formation by using the high fluorocarbon ratio, form a heavy polymer layer 14 on the inner wall of the intermediate etching structure 13 and the exposed surface of the organic mask 12 during the etching, and form a good protection for the organic mask 12, so that the organic mask 12 has a high selectivity, thereby playing a dual role of etching and protection and expanding the process window. At the same time, by using the directionless characteristics of the neutral particles, the isotropic etching of approximately 1:1 in the vertical and horizontal directions can be achieved, and the etching morphology of the intermediate etching structure 13 close to the bowl shape (arc-shaped recess) can be obtained (for reference Figure 3 ), and the polymer layer 14 covering the inner wall of the intermediate etching structure 13 can prevent the first etching from continuing, thereby ensuring the uniformity of the size in each cycle. Therefore, the embodiment of the present application can not only control the degree of lateral etching, but also can eliminate the independent and indispensable deposition step in the traditional periodic cycle etching process, and only needs to use the same set of process gas (first gas) system to complete the etching and deposition processes that need two sets of process gas (etching gas + deposition gas) system respectively, greatly simplifying the process, improving the efficiency, and reducing the control difficulty.

[0088] Step S14: performing anisotropic second etching on the polymer layer on the bottom of the intermediate etching structure, and exposing the substrate to perform the first etching on the exposed substrate again.

[0089] The second etching step in the etching process is used to perform the second etching on the polymer layer 14 on the inner wall bottom of the forming high aspect ratio etching structure, form a second opening on the polymer layer 14 on the bottom of the forming high aspect ratio etching structure, expose the substrate 10 located below the second opening, so that the first etching can be performed again through the second opening. Thus, the downward etching can be continued by performing the first etching again, thereby eliminating the problem of difficult continuous downward etching caused by the isotropic etching in the previous step. By repeatedly performing the first etching step and the second etching step multiple times, a high aspect ratio etching structure that is difficult to achieve by conventional processes can be achieved on the glass substrate.

[0090] Reference Figure 4In some embodiments, a second etching step in the etching process is performed, using charged particles in a plasma of a second gas, with the organic mask 12 as a mask, and through the first opening 11, to perform an anisotropic second etching on the polymer layer 14 on the bottom of the first intermediate etching structure 13, to etch through the polymer layer 14 covering the bottom of the first intermediate etching structure 13, so as to form a second opening 15 in the polymer layer 14 on the bottom of the first intermediate etching structure 13, to expose the substrate 10 under the second opening 15. In this way, the first etching can be performed again through the second opening 15, and a second intermediate etching structure 13 can be formed in succession on the substrate 10 under the second opening 15 (i.e., under the first intermediate etching structure 13) (see FIG. 2B). Figure 5 . .

[0091] The second gas is ionized to obtain a plasma of the second gas; and the ion filtering function of the process chamber is closed, i.e., the ion filtering is cancelled, so that the ions contained in the plasma of the second gas are retained to obtain charged particles. The charged particles in the obtained plasma of the second gas are used to perform the isotropic first etching on the polymer layer 14 on the bottom of the first intermediate etching structure 13, and to form a through second opening 15 in the polymer layer 14 on the bottom of the first intermediate etching structure 13.

[0092] In some embodiments, the second gas comprises an inert gas.

[0093] In some embodiments, the second gas comprises Ar.

[0094] In some embodiments, the second gas is Ar.

[0095] In some embodiments, the second etching step is performed using a second temperature, a second pressure, a second source power, and a second bias power. The second temperature is greater than 0°C (the second temperature can be the same as or different from the first temperature), the second pressure is less than the first pressure, the second source power is less than the first source power, and the second bias power is greater than the first bias power.

[0096] In some embodiments, the second temperature is 50°C to 90°C. For example, the second temperature can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, or 90°C, or any value between any two of the foregoing temperatures. However, the present application is not limited thereto.

[0097] In some embodiments, the second pressure is 10 mTorr to 100 mTorr. For example, the second pressure can be 10 mTorr, 20 mTorr, 30 mTorr, 40 mTorr, 50 mTorr, 60 mTorr, 70 mTorr, 80 mTorr, 90 mTorr, or 100 mTorr, or any value between any two of the foregoing pressure values. However, the application is not limited thereto.

[0098] In some embodiments, the second source power is 500 W to 1000 W. For example, the second source power can be 500 W, 600 W, 700 W, 800 W, 900 W, or 1000 W, or any value between any two of the foregoing source power values. However, the application is not limited thereto.

[0099] In some embodiments, the second bias power is 50 W to 100 W. For example, the second bias power can be 50 W, 60 W, 70 W, 80 W, 90 W, or 100 W, or any value between any two of the foregoing bias power values. However, the application is not limited thereto.

[0100] The embodiments of the present application use Ar as the second gas for the second etching, which not only can perform directional bombardment on the inner wall bottom of the high aspect ratio etching structure being formed, remove the polymer layer 14 on the inner wall bottom, expose the underlying substrate 10, and perform the first etching again, but also can take advantage of the characteristic that Ar has no obvious etching effect on the substrate 10 (relative to conventional etching gases such as fluorine-containing gas), avoid damaging the etching morphology formed, prevent the problem of the size of the upper portion becoming larger and larger with repeated etching, and ensure the etching uniformity and perpendicularity, thereby being more conducive to realizing the etching structure with higher aspect ratio and higher interconnection density on the glass substrate, which is difficult to realize by conventional processes.

[0101] In some embodiments, another implementation of the second gas is that the inert gas in the second gas is replaced by a chlorine-containing gas.

[0102] In some embodiments, another implementation of the second gas is that the second gas includes an inert gas and a chlorine-containing gas.

[0103] In some embodiments, another implementation of the second gas is that the second gas is an inert gas and a chlorine-containing gas.

[0104] In some embodiments, the chlorine-containing gas includes BCl3.

[0105] For example, another implementation of the second gas is that the second gas includes BCl3and does not include Ar. Alternatively, the second gas is BCl3. Alternatively, the second gas includes Ar and BCl3. Alternatively, the second gas is Ar and BCl3.

[0106] In some embodiments, the total flow rate of the second gas is 50 sccm to 1000 sccm. For example, the total flow rate of the second gas can be 50 sccm, 60 sccm, 90 sccm, 100 sccm, 200 sccm, 500 sccm, 800 sccm, or 1000 sccm, or any value between any two of the foregoing flow rates. However, the disclosure is not limited thereto.

[0107] In some embodiments, when the second gas includes Ar and BCl3 (or the second gas is Ar and BCl3), the following flow rate ratio relationship can be had:

[0108] Ar:BCl3=1:1 to 10:1. However, the disclosure is not limited thereto.

[0109] In some embodiments, before the etching process is performed, a second etching step included in the etching process is also used as a pretreatment process. The pretreatment process is used to modify the surface of the organic mask 12 using the Ar plasma in the second gas used in the second etching step to reduce the surface roughness of the organic mask 12 and improve the pattern accuracy of the organic mask 12, so as to improve the deposition quality of the polymer layer 14 when the first etching step included in the etching process is subsequently performed, thereby improving the protection capability of the organic mask 12 and reducing the consumption of the organic mask 12, and thus the selectivity of the organic mask 12 can be further improved. Then the etching process is performed.

[0110] Step S15: Steps S13 to S14 are repeatedly performed until a high aspect ratio etching structure is formed on the substrate.

[0111] Reference Figure 5 In some embodiments, the above step S13 is repeatedly performed, i.e., the first etching step in the etching process is repeatedly performed using the neutral particles in the plasma of the first gas to mask the organic mask 12 and perform isotropic first etching on the substrate 10 exposed below the second opening 15 through the first opening 11 and the second opening 15, to successively form a second intermediate etching structure 13 on the substrate 10 below the second opening 15 (below the first intermediate etching structure 13). At the same time, the polymer layer 14 is again formed on the inner wall of the second intermediate etching structure 13 (also including the first intermediate etching structure 13) and the entire exposed surface of the organic mask 12 by virtue of the strong polymer forming capability of the first gas.

[0112] Next, the above step S14 is repeated, i.e. the second etching step in the etching process is repeated, using charged particles in the plasma of the second gas to anisotropically etch the polymer layer 14 on the bottom of the second intermediate etching structure 13 through the first opening 11 and the second opening 15 (first second opening 15) with the organic mask 12 as a mask, and etching through the polymer layer 14 covering the bottom of the second intermediate etching structure 13, so that a second opening 15 (second second opening 15) is also formed in the polymer layer 14 on the bottom of the second intermediate etching structure 13, exposing the substrate 10 below the second opening 15.

[0113] By analogy, by continuing to repeat the above steps S13 to S14, a third intermediate etching structure 13 and a third second opening 15, a fourth intermediate etching structure 13 and a fourth second opening 15, etc. can be successively formed below the second intermediate etching structure 13 and the second second opening 15, until finally a high aspect ratio etching structure 16 with a target aspect ratio composed of successive intermediate etching structures 13 is formed on the substrate 10 from top to bottom, as shown in Figure 6 Figure 6 Only the case where six intermediate etching structures 13 (first intermediate etching structure 13, second intermediate etching structure 13, third intermediate etching structure 13, fourth intermediate etching structure 13, fifth intermediate etching structure 13 and sixth intermediate etching structure 13 from top to bottom) are formed on the substrate 10 is shown. However, it can be understood that other desired number of intermediate etching structures 13 can be formed on the substrate 10, and therefore should not be construed as a limitation of the present application. Moreover, when performing the last cycle, since there is no need to form a second opening, the second etching step can be omitted when performing the last cycle.

[0114] In some embodiments, the etching process for etching to form a high aspect ratio etching structure 16 (e.g. a TGV) according to the embodiments of the present application is a plurality of periodic cycle etching steps formed in sequence by the first etching step and the second etching step. Alternatively, the etching process according to the embodiments of the present application is based on a plurality of periodic cycle etching steps, only including the above-mentioned first etching step and second etching step in sequence, and does not contain other etching steps for etching the substrate 10 and other deposition steps for depositing polymers independently.

[0115] ​In some embodiments, the etching process can include sequentially connected first, second and third etching stages for forming sequentially connected top, middle and bottom portions of the high aspect ratio etched structure 16, respectively. And the carbon-fluorine ratio of the first gas used in the first etching step in the first etching stage, the carbon-fluorine ratio of the first gas used in the first etching step in the second etching stage, and the carbon-fluorine ratio of the first gas used in the first etching step in the third etching stage are sequentially increased. For example, in the first etching stage, the first gas used in the first etching step can include a carbon-fluorine gas with a carbon-fluorine ratio equal to 1:3, such as CHF3, etc.; in the second etching stage, the first gas used in the first etching step can include a carbon-fluorine gas with a carbon-fluorine ratio equal to 1:2, such as C4F8, CH2F2, etc.; in the third etching stage, the first gas used in the first etching step can include a carbon-fluorine gas with a carbon-fluorine ratio greater than 1:2, such as C4F6, C5F8, etc. In this way, with the increase of the depth of the high aspect ratio etched structure 16, the deposition can be enhanced by providing a higher carbon-fluorine ratio, which can effectively inhibit the lateral etching of the bottom of the sidewall, eliminate the problem of bottom side notching, and further ensure the size uniformity and perpendicularity along the depth direction. By performing the etching process in stages, not only the limitations of the conventional single etching process which cannot achieve high precision control are overcome, but also a more precise and controllable etching scheme is provided for the manufacture of high-performance devices, effectively expanding the etching process window, and being conducive to realizing higher aspect ratio and higher interconnection density of glass vias.

[0116] In some embodiments, after forming the high aspect ratio etched structure 16 as shown in Figure 6 , the method can further include: removing the organic mask 12 on the surface of the substrate 10 using plasma of a fifth gas. The plasma of the fifth gas is obtained by ionizing the fifth gas introduced into the process chamber. After removing the organic mask 12, the structure is as shown in Figure 7 .

[0117] In some embodiments, the fifth gas includes an oxidizing gas. For example, the fifth gas can include O2.

[0118] It should be noted that due to the process characteristics of the periodic cyclic etching, regular tooth-like lines (see Figure 6 ) will inevitably be formed on the sidewall of the high aspect ratio etched structure 16 from top to bottom, and the tooth-like lines have a certain degree of protrusion (nanometer level). Therefore, it can be determined according to the design requirements whether the sidewall needs to be treated to make the sidewall smoother. And the known applicable processes for treating the sidewall can be referred to. When it is determined according to the design requirements that the sidewall does not need to be treated, after performing the etching process to form the high aspect ratio etched structure 16 as shown in Figure 6 , the plasma of the fifth gas is directly used to remove the organic mask 12 on the surface of the substrate 10, and the structure obtained is as shown inFigure 7 The structure is shown.

[0119] In some embodiments, when it is determined that the sidewall needs to be processed according to design requirements, the embodiments of the present application further provide a sidewall processing method, which can be used to process the sidewall of the high aspect ratio etching structure 16 formed as shown to obtain better sidewall smoothness. The processing method comprises: Figure 6 The structure is shown.

[0120] After the high aspect ratio etching structure 16 is formed, a processing process is performed to remove at least part of the tooth-like pattern existing on the sidewall of the high aspect ratio etching structure 16; wherein the processing process comprises a deposition step and a third etching step; the deposition step is used to deposit a protective layer (mainly composed of polymer) on the sidewall of the high aspect ratio etching structure 16 by using plasma of a third gas; the third etching step is used to remove part of the thickness of the protective layer deposited on the sidewall by using plasma of a fourth gas, and react with the substrate 10 material existing on and exposed on the surface of the tooth-like pattern to remove at least part of the tooth-like pattern.

[0121] In some embodiments, the third gas is ionized to obtain plasma of the third gas by passing the third gas into the process chamber, and the ion filtering function of the process chamber is closed, i.e. the ion filtering is cancelled, so that the plasma of the third gas containing charged particles is used to process the sidewall of the high aspect ratio etching structure 16 to deposit a protective layer on the sidewall of the high aspect ratio etching structure 16. The fourth gas is ionized to obtain plasma of the fourth gas by passing the fourth gas into the process chamber, and the ion filtering function of the process chamber is closed, i.e. the ion filtering is cancelled, so that the plasma of the fourth gas containing charged particles is used to remove part of the thickness of the protective layer deposited on the sidewall, and react with the substrate 10 material existing on and exposed on the surface of the tooth-like pattern to remove at least part of the tooth-like pattern.

[0122] In some embodiments, the third gas comprises a hydrocarbon gas. For example, the third gas comprises CH4, etc., and He can be used as an auxiliary gas. Alternatively, the third gas is CH4, and He can be used as an auxiliary gas. CH4 is a gas with strong polymer forming ability, and by using CH4, a polymer mainly composed of C can be formed to form the protective layer.

[0123] In some embodiments, the third gas includes a fluorocarbon gas having a fluorine-to-carbon ratio greater than or equal to 1:2. For example, the third gas includes at least one of C4F8, C4F6, C5F8, CH3F, and N2may be used as an auxiliary gas. Alternatively, the third gas is any one of C4F8, C4F6, C5F8, CH3F, and N2may be used as an auxiliary gas. By adding N2to the fluorocarbon gas, the third gas can mainly function to deposit a polymer (a C-N polymer or a C-H-N polymer can be formed, and a C-containing polymer can be generated by self-decomposition) to form a protective layer.

[0124] By using a gas having a strong polymer-forming ability as the third gas, a polymer can be deposited on the sidewall to form a protective layer, which prevents the etching reaction from continuing to protect the sidewall from lateral etching, thereby preventing the problem of size expansion.

[0125] In some embodiments, the fourth gas includes a fluorine-containing gas having a weak polymer-forming ability. For example, the fourth gas includes at least one of SF6, CF4, NF3, and Ar can be used as an auxiliary gas. Alternatively, the fourth gas is any one of SF6, CF4, NF3, and Ar can be used as an auxiliary gas. By using at least one of SF6, CF4, and NF3, the protective layer on the sidewall can be removed by a certain thickness, the end of the tooth-shaped pattern can be exposed, and the exposed substrate 10 material (SiO2) can be reacted, thereby removing at least part of the tooth-shaped pattern. By repeatedly performing the deposition step and the third etching step in the processing process, the tooth-shaped pattern on the sidewall can be completely or substantially removed.

[0126] In some embodiments, the deposition step and the third etching step are repeatedly performed for 10 to 30 times (1 cycle is defined as 1 deposition step and 1 third etching step are continuously performed). For example, the number of cycles can be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30. Alternatively, the number of cycles can be less than 10 or more than 30 (depending on the protrusion height of the tooth-shaped pattern).

[0127] In some embodiments, the deposition step is performed using a third pressure which is a high pressure, and the third etching step is performed using a fourth pressure which is a low pressure, and the third pressure is greater than the fourth pressure. In this case, there are recesses between adjacent teeth on the sidewall. By using the third pressure which is a high pressure in the deposition step and turning off the bias power, the third gas can be made to stay and accumulate on the sidewall surface at the recesses where the flow rate is relatively weak, and the flow rate of the third gas on the sidewall surface at the ends of the teeth is relatively fast, and the structure at the ends of the teeth is special, and the polymer has relatively few attachment points, so the polymer deposition at the ends of the teeth is very little. Since a part of the polymer (protective layer) on the sidewall is consumed when the fourth gas is used, by using the fourth pressure which is a low pressure and applying a relatively large bias power, the flow rate of the fourth gas can be accelerated and given directionality, so that the etching is mainly concentrated on the ends of the teeth (because the polymer deposited at the ends of the teeth is originally little, and the ends of the teeth are exposed due to the consumption of the polymer by the fourth gas). The sidewall surface at the recesses has relatively thick polymer, so it can effectively protect the sidewall when the third etching step is performed.

[0128] In some embodiments, the deposition step is performed using a third temperature, a third pressure, a third source power and a third bias power.

[0129] In some embodiments, the third temperature is 10-20℃. For example, the third temperature can be 10℃, 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃ or 20℃, or any value between any two of the foregoing temperature values. However, the application is not limited thereto.

[0130] In some embodiments, the third pressure is 1-5 Torr. For example, the third pressure can be 1 Torr, 1.3 Torr, 1.5 Torr, 1.7 Torr, 2 Torr, 3 Torr, 4 Torr or 5 Torr, or any value between any two of the foregoing pressure values. However, the application is not limited thereto.

[0131] In some embodiments, the third source power is 100-500 W. For example, the third source power can be 100 W, 200 W, 300 W, 400 W or 500 W, or any value between any two of the foregoing source power values. However, the application is not limited thereto.

[0132] In some embodiments, the third bias power is 0 W (turning off the bias power).

[0133] In some embodiments, the total flow rate of the third gas (including the auxiliary gas) is 100 sccm to 500 sccm. For example, the total flow rate of the third gas can be 100 sccm, 200 sccm, 300 sccm, 400 sccm, or 500 sccm, or any value between any two of the aforementioned flow rates. However, the disclosure is not limited thereto.

[0134] In some embodiments, when the third gas includes CH4and He is used as the auxiliary gas, the following flow rate ratio relationship can be used: CH4:He = 0.2:1 to 1:1. However, the disclosure is not limited thereto.

[0135] In some embodiments, when the third gas includes any one of C4F8, C4F6, C5F8, CH3F, and N2is used as the auxiliary gas, the following flow rate ratio relationship can be used:

[0136] C4F8:N2= 1:8 to 1:10; C4F6:N2= 1:3 to 1:5; C5F8:N2= 1:3 to 1:5; CH3F:N2= 1:2 to 1:5. However, the disclosure is not limited thereto.

[0137] In some embodiments, the third etching step is performed using a fourth temperature, a fourth pressure, a fourth source power, and a fourth bias power.

[0138] In some embodiments, the fourth temperature is 10°C to 20°C. For example, the fourth temperature can be 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, or 20°C, or any value between any two of the aforementioned temperatures. However, the disclosure is not limited thereto.

[0139] In some embodiments, the fourth pressure is 30 mTorr to 100 mTorr. For example, the fourth pressure can be 30 mTorr, 40 mTorr, 50 mTorr, 60 mTorr, 70 mTorr, 80 mTorr, 90 mTorr, or 100 mTorr, or any value between any two of the aforementioned pressures. However, the disclosure is not limited thereto.

[0140] In some embodiments, the fourth source power is 100 W to 1000 W. For example, the fourth source power can be 100 W, 200 W, 300 W, 400 W, 500 W, 600 W, 700 W, 800 W, 900 W, or 1000 W, or any value between any two of the aforementioned source powers. However, the disclosure is not limited thereto.

[0141] In some embodiments, the fourth bias power is 1000W-2000W. For example, the fourth bias power can be 1000W, 1100W, 1200W, 1300W, 1400W, 1500W, 1600W, 1700W, 1800W, 1900W, 2000W, or any value between any two of the foregoing bias power values. However, the application is not limited thereto.

[0142] In some embodiments, the total flow rate of the fourth gas (including auxiliary gas) is 50sccm-200sccm. For example, the total flow rate of the fourth gas can be 50sccm, 60sccm, 80sccm, 100sccm, 120sccm, 150sccm, 170sccm, or 200sccm, or any value between any two of the foregoing flow rate values. However, the application is not limited thereto.

[0143] In some embodiments, when the fourth gas includes any one of SF6, CF4, NF3, and Ar is used as the auxiliary gas, the following flow rate ratio relationship can be obtained:

[0144] SF6:Ar=1:10-1:20; CF4:Ar=1:5-1:10; NF3:Ar=1:5-1:10. However, the application is not limited thereto.

[0145] In some embodiments, the application also provides a side wall processing method, which can be used to process the side wall of the high aspect ratio etching structure 16 in formation. The processing method includes:

[0146] In the process of forming the high aspect ratio etching structure 16, after completing a preset number of first etching steps, a processing process is performed to remove at least part of the tooth-like pattern existing on the side wall of the high aspect ratio etching structure 16 in formation; wherein the processing process includes a deposition step and a third etching step; the deposition step is used to deposit a protective layer (composed of a polymer) on the side wall of the high aspect ratio etching structure 16 in formation using the plasma of the third gas (with ion filtering turned off); the third etching step is used to remove part of the thickness of the protective layer deposited on the side wall using the plasma of the fourth gas (with ion filtering turned off), and react with the substrate 10 material existing and exposed on the surface of the tooth-like pattern to remove at least part of the tooth-like pattern.

[0147] By performing the periodic circulation of the deposition step and the third etching step and the alternating circulation between performing the etching process, the etching rate and the sidewall quality can be balanced, so as to realize the high etching rate and high etching precision of the high aspect ratio etching structure 16, and effectively improve the uniformity and roughness of the local polymer, avoid the titling problem, realize higher verticality, and realize better size uniformity (the size uniformity of the upper, middle and lower positions of the high aspect ratio etching structure 16), and better sidewall smoothness.

[0148] In some embodiments, the preset number of times is 1-5 times. For example, the preset number of times can be 1 time, 2 times, 3 times, 4 times or 5 times, etc. But it can not be limited to this.

[0149] In some embodiments, when the sidewall of the forming high aspect ratio etching structure 16 is processed, when the fourth gas uses CF4, the exposed surface of the organic mask 12 (photoresist mask) can also be processed by using the plasma of CF4, and a carbon-containing protective film is formed on the exposed surface of the organic mask 12, which can reduce the consumption rate of the organic mask 12, improve the selectivity, and use the covered carbon-containing protective film to improve the surface quality and size precision of the organic mask 12, so as to obtain a more vertical sidewall, thereby having a positive significance for realizing a higher aspect ratio and a higher interconnection density.

[0150] In some embodiments, when the sidewall of the forming high aspect ratio etching structure 16 is processed, when the etching process includes a first etching stage, a second etching stage and a third etching stage connected in sequence, which are respectively used to form the top, middle and bottom of the high aspect ratio etching structure 16 in sequence, the fluorocarbon ratio of the third gas used in the deposition step in the first etching stage, the fluorocarbon ratio of the third gas used in the deposition step in the second etching stage and the fluorocarbon ratio of the third gas used in the deposition step in the third etching stage increase in sequence. For example, when the third gas includes C4F8, C4F6, C5F8, CH3F, CH4, in the first etching stage, the third gas used in the deposition step can include a fluorocarbon gas with a fluorocarbon ratio equal to 1:2, such as C4F8; in the second etching stage, the third gas used in the deposition step can include a fluorocarbon gas with a fluorocarbon ratio greater than 1:2 and less than 1:1, such as C4F6, C5F8, etc.; in the third etching stage, the third gas used in the deposition step can include a fluorocarbon gas with a fluorocarbon ratio equal to 1:1, such as CH3F, or it can also be CH4, etc. In this way, with the increase of the depth of the high aspect ratio etching structure 16, the deposition can be enhanced by providing a higher fluorocarbon ratio, which can effectively inhibit the lateral etching of the sidewall bottom, eliminate the problem of bottom side digging, thereby further ensuring the size uniformity and verticality along the depth direction, expanding the process window, and being beneficial to realizing a glass via with a higher aspect ratio and a higher interconnection density.

[0151] Other aspects (gas species, cycle number, temperature, pressure, power, gas flow, flow ratio, etc.) of the processing procedure for processing the sidewalls of the high aspect ratio etched structure 16 in formation can be the same as the corresponding aspects of the processing procedure for processing the sidewalls of the high aspect ratio etched structure 16 after formation, as described above, and are understood in light of the foregoing.

[0152] After processing the sidewalls, the high aspect ratio etched structure 16 with smoother sidewalls is obtained, as shown in Figure 8

[0153] In some embodiments, after forming the high aspect ratio etched structure 16 with sidewall processing, the organic mask 12 on the surface of the substrate 10 can be removed according to the method described above. The structure after removing the organic mask 12 is shown in Figure 9

[0154] According to a second aspect of the present application, the embodiments of the present application further provide an etched structure, which is obtained by using the substrate etching method according to any one of the embodiments of the first aspect described above.

[0155] Referring to Figure 7 or Figure 9 In some embodiments, the etched structure can be a high aspect ratio etched structure 16. The high aspect ratio etched structure 16 is formed on the surface of the substrate 10. The high aspect ratio etched structure 16 can be, for example, a deep trench, a deep hole, or a via, etc.

[0156] In some embodiments, the high aspect ratio etched structure 16 can be a high aspect ratio etched structure 16 without sidewall processing, as shown in Figure 7

[0157] In some embodiments, the high aspect ratio etched structure 16 can be a high aspect ratio etched structure 16 with sidewall processing, as shown in Figure 9

[0158] In some embodiments, the high aspect ratio etched structure 16 can be formed on the surface of a glass substrate, and form a through glass via (TGV).

[0159] In some embodiments, the glass substrate with the through glass via can be applied in the fields of high frequency communication, optoelectronics, 3D integration and advanced packaging, etc.

[0160] In a third aspect, the embodiments of the present application further provide a plasma processing device, which is used to perform the substrate etching method corresponding to the above-described embodiments to form the high aspect ratio etched structure 16 (etched structure) corresponding to the above-described embodiments. The plasma processing device includes an inductively coupled plasma (ICP) etching device or a capacitively coupled plasma (CCP) etching device, etc.​​​​

[0161] In other aspects, the embodiments of the present application also provide an electronic device including the high aspect ratio etching structure 16 (e.g., glass via hole, etc.) obtained by using the substrate etching method of the above embodiments. The electronic device can be a storage device, a mobile phone, a computer, a tablet computer, an electronic instrument, a television, an artificial intelligence device, etc.

[0162] In summary, the embodiments of the present application etch the substrate 10 by using the organic mask 12 and the etching process including multiple periodic cyclic etching steps formed in the first etching step and the second etching step, perform isotropic first etching on the substrate 10 by using neutral particles in the plasma of the first gas (including fluorine-containing gas), form the polymer layer 14 which protects the inner wall of the etching structure and the organic mask 12, perform anisotropic second etching on the polymer layer 14 on the bottom of the inner wall by using charged particles in the plasma of the second gas (including inert gas), expose the underlying substrate 10, and perform first etching again, thereby significantly improving the selectivity of the organic mask 12, realizing the formation of the high aspect ratio etching structure 16 on the substrate 10 by using the organic mask 12 to replace the traditional metal hard mask, improving the etching uniformity and perpendicularity, avoiding the pollution problem when using the metal mask, simplifying the process, and improving the efficiency.

[0163] The above is only the preferred embodiments of the present application, and the embodiments are not intended to limit the protection scope of the present application, so any equivalent changes made according to the content of the specification and drawings of the present application should also be included in the protection scope of the present application.

Claims

1. A method of etching a substrate, the method comprising: The method comprises: providing a substrate; forming a plurality of organic masks on a surface of the substrate, with a first opening between any two adjacent organic masks; performing an etching process to etch the surface of the substrate exposed in the first opening, and form a high aspect ratio etching structure on the substrate; wherein the etching process comprises a plurality of periodic and cyclic etching steps formed in sequence by a first etching step and a second etching step; the first etching step uses neutral particles in plasma of a first gas to perform isotropic first etching on the substrate, and forms a polymer layer on the inner wall of the high aspect ratio etching structure being formed and the exposed surface of the organic mask, so as to protect the inner wall and the organic mask during the first etching; the second etching step uses charged particles in plasma of a second gas to perform anisotropic second etching on the polymer layer on the bottom of the inner wall, and forms a second opening on the polymer layer on the bottom to expose the substrate, so as to perform the first etching again through the second opening; the first gas comprises a fluorine-containing gas, and the second gas comprises an inert gas.

2. The substrate etching method according to claim 1, wherein The ions contained in the plasma formed by the first gas are filtered out by performing ion filtering to obtain the neutral particles; and the ions contained in the plasma formed by the second gas are retained by canceling ion filtering to obtain the charged particles.

3. The method of claim 1, wherein The substrate comprises a glass substrate; and the first gas comprises a fluorocarbon gas with a fluorocarbon ratio greater than or equal to 1:

3.

4. The substrate etching method according to claim 3, wherein The glass substrate comprises a SiO2 substrate; and / or, the first gas comprises at least one of C4F8, C4F6, C5F8, CHF3, and CH2F2; and / or, the organic mask comprises a photoresist mask.

5. The method of claim 1, wherein The second gas comprises Ar.

6. The method of claim 1, wherein The first etching step is performed using a first temperature, a first pressure, and a first bias power, and the second etching step is performed using a second temperature, a second pressure, and a second bias power, wherein the first temperature and the second temperature are greater than 0℃, the first pressure is greater than the second pressure, and the first bias power is less than the second bias power.

7. The method of claim 6, wherein The first temperature is 50℃-90℃; and / or, the first pressure is 100mTorr-10Torr; and / or, the first bias power is 0W; and / or, the second temperature is 50℃-90℃; and / or, the second pressure is 10mTorr-100mTorr; and / or, the second bias power is 50W-100W.

8. The method of claim 1, wherein Another implementation is that the inert gas in the second gas is replaced by a chlorine-containing gas, or the second gas comprises the inert gas and the chlorine-containing gas.

9. The method of claim 8, wherein The chlorine-containing gas comprises BCl3.

10. An etching structure, characterized by The substrate etching method is obtained by using the method according to any one of claims 1-9.

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