Manufacturing method of groove
By adopting a stacked structure of mask-like and hard mask layer in the lithography process, combined with the etching technology with high selection ratio, the thickness loss problem of hard mask layer is solved, the trench quality is improved and its application is expanded Manufacture of semiconductor devices ranging from 45 nm or above.
Patent Information
- Application Number
- CN202411138044.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-19
- Publication Date
- 2024-12-20
AI Technical Summary
In the prior art, the thickness loss of the hard mask layer of the trench is severe, resulting in low trench quality, limiting its application range at process nodes above 45nm.
In the lithography process, a stacked structure of a mask-like layer and a hard mask layer is adopted to reduce the thickness loss of the hard mask layer through masking of the mask-like layer, and during the etching process of the buffer layer and the substrate, The etch selection ratio of the mask-like layer to the buffer layer is improved to form a high-quality third trench.
It effectively avoids thickness loss of the hard mask layer, improves the quality of the trench, makes it suitable for semiconductor devices above 45nm, and expands its application range.
Smart Images
Figure CN119170496A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of semiconductor integrated circuit manufacturing and relates to a method for manufacturing a groove. Background Art
[0002] Trench structures such as trench isolation structures and trench gate structures are commonly used structures in semiconductor devices. At present, for etching trenches on silicon substrates, a liner silicon nitride layer with a high etching selectivity ratio with the silicon substrate is often used as a hard mask layer for etching the trenches. In order to buffer the stress between the liner silicon nitride layer and the substrate, a thin liner silicon oxide layer is formed between the liner silicon nitride layer and the substrate, and then a stacked carbon coating (SOC layer), a silicon-oxygen anti-reflective layer (SHB layer) and a patterned photoresist layer are sequentially formed on the liner silicon nitride layer, such as Figure 1 As shown, it is a schematic diagram of the cross-sectional structure after a patterned photoresist layer is formed on a substrate, including a substrate 01, a pad silicon oxide layer 011, a pad silicon nitride layer 012, a carbon coating 013, a silicon-based anti-reflection layer 014 and a photoresist layer 015. After the patterned photoresist layer is formed, the pattern in the photoresist layer is transferred to the silicon-based anti-reflection layer and the carbon coating, and then the silicon-based anti-reflection layer is removed and the carbon coating is thinned, and then the pattern in the carbon coating is transferred to the pad silicon nitride layer and the carbon coating is removed, and then the pad silicon oxide layer at the bottom of the pattern in the pad silicon nitride layer is etched by an isotropic dry etching process, and finally the substrate is etched based on the pattern in the pad silicon nitride layer. However, when etching the pad oxide layer and the silicon substrate, the etching selectivity of the pad silicon oxide layer and the silicon substrate to the pad silicon nitride layer is relatively low, resulting in a serious loss in the thickness of the pad silicon nitride layer, as shown in FIG. Figure 2 As shown in FIG. 1 , it is a schematic diagram of the cross-sectional structure after the groove is formed, including a substrate 01, a liner silicon oxide layer 011, a liner silicon nitride layer 012 and a groove 02. It can be seen from the figure that after the groove is formed, the liner silicon nitride layer is significantly lost, and the thickness of the liner silicon nitride layer will affect the quality of the formed groove. In addition, for semiconductor devices with process nodes above 45nm, some processes do not allow the thickness of the liner silicon nitride layer to be damaged in order to ensure the quality of the manufactured grooves. The trench etching process cannot be applied to the manufacture of semiconductor devices with process nodes above 45nm due to the obvious thinning of the thickness of the liner silicon nitride layer, which limits the application scope of the process.
[0003] Therefore, there is an urgent need to find a method for manufacturing a trench that avoids loss of thickness of the hard mask layer and improves the quality of the trench. Summary of the invention
[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for manufacturing a groove, which is used to solve the problem of low quality of the manufactured groove caused by serious thickness loss of the hard mask layer in the photolithography process in the prior art.
[0005] To achieve the above object and other related objects, the present invention provides a method for manufacturing a groove, comprising the following steps:
[0006] Providing a substrate, and forming a buffer layer, a hard mask layer, a mask-like layer, a carbon-containing layer and an intermediate anti-reflection layer stacked in sequence on the upper surface of the substrate;
[0007] Forming a patterned shielding layer on the upper surface of the intermediate anti-reflection layer, and forming a first groove penetrating the intermediate anti-reflection layer and the carbon-containing layer based on the patterned shielding layer;
[0008] removing the shielding layer and the intermediate anti-reflection layer in sequence, and thinning the carbon-containing layer;
[0009] forming a second groove penetrating the mask-like layer and the hard mask layer based on the first groove in the remaining carbon-containing layer, and removing the remaining carbon-containing layer;
[0010] The buffer layer and the substrate are etched based on the second trench to obtain a third trench located in the substrate.
[0011] Optionally, the material of the hard mask layer includes silicon nitride.
[0012] Optionally, the material of the mask-like layer includes aluminum nitride, silicon carbon nitride, tantalum nitride, and titanium nitride.
[0013] Optionally, a thickness of the mask-like layer is smaller than a thickness of the hard mask layer.
[0014] Optionally, the thickness of the carbon-containing layer is in the range of The thickness of the intermediate anti-reflection layer is in the range of
[0015] Optionally, the method of removing the intermediate anti-reflection layer includes chemical mechanical grinding, dry etching, and wet etching; the method of thinning the carbon-containing layer includes chemical mechanical grinding, dry etching, and wet etching.
[0016] Optionally, during the process of forming the second trench, an etching gas for etching the mask-like layer is different from an etching gas for etching the hard mask layer.
[0017] Optionally, the method of removing the remaining carbon-containing layer includes dry etching and wet etching.
[0018] Optionally, a method of etching the buffer layer at the bottom of the second trench includes isotropic dry etching.
[0019] Optionally, during etching of the buffer layer at the bottom of the second trench, an etching selectivity ratio between the mask-like layer and the buffer layer is greater than an etching selectivity ratio between the hard mask layer and the buffer layer.
[0020] As described above, the groove manufacturing method of the present invention forms a mask-like layer on the upper surface of the hard mask layer by improving the groove photolithography process, and when the buffer layer and the substrate under the second groove are etched, the etching selectivity ratio between the mask-like layer and the buffer layer and the substrate is greater than the etching selectivity ratio between the hard mask layer and the buffer layer and the substrate, so that in the process of forming the third groove, the thickness of the mask-like layer is only slightly lost, and due to the masking of the mask-like layer, the loss of the thickness of the hard mask layer is avoided, so that the thickness of the stacked structure formed by the hard mask layer and the mask-like layer is guaranteed, thereby improving the quality of the third groove, so that the manufacturing of the third groove can be applied to semiconductor devices above 45nm process node, expanding the application range of the groove, and having high industrial utilization value. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 Shown is a schematic cross-sectional structure diagram of a stacked film layer structure after a patterned photoresist layer is formed.
[0022] Figure 2 Shown is a schematic cross-sectional structure diagram of a stacked film layer structure after grooves are formed.
[0023] Figure 3 The process flow chart of the trench manufacturing method of the present invention is shown.
[0024] Figure 4 It is a schematic diagram showing the cross-sectional structure after forming a patterned shielding layer in the method for manufacturing the groove of the present invention.
[0025] Figure 5 It is a schematic diagram showing the cross-sectional structure after forming the first groove in the groove manufacturing method of the present invention.
[0026] Figure 6 It is a schematic diagram showing the cross-sectional structure after thinning the carbon-containing layer in the groove manufacturing method of the present invention.
[0027] Figure 7 It is a schematic diagram showing the cross-sectional structure after removing the remaining carbon-containing layer in the method for manufacturing the groove of the present invention.
[0028] Figure 8 It is a schematic diagram of the cross-sectional structure after removing the buffer layer at the bottom of the second trench in the method for manufacturing the trench of the present invention.
[0029] Fig. 9It is a schematic diagram showing the cross-sectional structure after forming the third groove in the groove manufacturing method of the present invention.
[0030] Description of Figure Numbers
[0031] 01 Substrate
[0032] 011 Pad silicon oxide layer
[0033] 012 Pad silicon nitride layer
[0034] 013 Carbon coating
[0035] 014 Silicon-based anti-reflective layer
[0036] 015 Photoresist layer
[0037] 02 Groove
[0038] 1 Substrate
[0039] 11 Buffer layer
[0040] 12 Hard mask layer
[0041] 13 types of mask layers
[0042] 14 Carbon-containing layer
[0043] 15. Intermediate anti-reflection layer
[0044] 16 Shielding layer
[0045] 2 First groove
[0046] 3 Second groove
[0047] 4 Third groove DETAILED DESCRIPTION
[0048] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.
[0049] See also Figures 3 to 9 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.
[0050] This embodiment provides a method for manufacturing a groove, such as Figure 3 FIG. 1 is a process flow chart of the method for making the groove, which includes the following steps:
[0051] S1: providing a substrate, and forming a buffer layer, a hard mask layer, a mask-like layer, a carbon-containing layer and an intermediate anti-reflection layer stacked in sequence on the upper surface of the substrate;
[0052] S2: forming a patterned shielding layer on the upper surface of the intermediate anti-reflection layer, and forming a first groove penetrating the intermediate anti-reflection layer and the carbon-containing layer based on the patterned shielding layer;
[0053] S3: removing the shielding layer and the intermediate anti-reflection layer in sequence, and thinning the carbon-containing layer;
[0054] S4: forming a second groove penetrating the mask-like layer and the hard mask layer based on the first groove in the remaining carbon-containing layer, and removing the remaining carbon-containing layer;
[0055] S5: etching the buffer layer and the substrate based on the second trench to obtain a third trench located in the substrate.
[0056] See also Figures 4 to 6 , perform the step S1, the step S2 and the step S3: provide a substrate 1, and form a buffer layer 11, a hard mask layer 12, a mask-like layer 13, a carbon-containing layer 14 and an intermediate anti-reflection layer 15 stacked in sequence on the upper surface of the substrate 1; form a patterned shielding layer 16 on the upper surface of the intermediate anti-reflection layer 15, and form a first groove 2 penetrating the intermediate anti-reflection layer 15 and the carbon-containing layer 14 based on the patterned shielding layer 16; remove the shielding layer 16 and the intermediate anti-reflection layer 15 in sequence, and thin the carbon-containing layer 14.
[0057] Specifically, the substrate 1 is made of silicon, silicon carbide, silicon germanium, diamond, gallium nitride or other suitable semiconductor materials. Preferably, a silicon wafer is used as the substrate 1.
[0058] Specifically, under the condition of ensuring the performance of the device, the thickness, size and shape of the substrate 1 can be selected according to actual conditions and are not limited here.
[0059] Specifically, the method of forming the buffer layer 11 includes chemical vapor deposition, physical vapor deposition, thermal oxidation or other suitable methods.
[0060] Specifically, the buffer layer 11 is used to buffer the stress between the hard mask layer 12 and the substrate 1 , and to enhance the bonding force between the hard mask layer 12 and the substrate 1 .
[0061] Specifically, the material of the buffer layer 11 includes silicon oxide, silicon oxynitride or other suitable hard mask buffer materials. Preferably, a thin silicon oxide layer is used as the buffer layer 11 .
[0062] Specifically, under the condition of ensuring the quality of the formed hard mask layer 12 , the thickness of the buffer layer 11 can be selected according to actual conditions, and is not limited here.
[0063] Specifically, the hard mask layer 12 is used to mask the non-etched area in the subsequent etching process of the substrate 1 to protect the non-etched area. Therefore, there is a relatively high etching selectivity ratio between the hard mask layer 12 and the substrate 1 .
[0064] As an example, the material of the hard mask layer 12 includes silicon nitride, a silicon nitride / silicon oxide composite layer or other suitable materials. Preferably, silicon nitride is used as the hard mask layer 12.
[0065] Specifically, the method of forming the hard mask layer 12 includes chemical vapor deposition, physical vapor deposition or other suitable methods.
[0066] Specifically, the thickness of the hard mask layer 12 is in the range of Preferably, the thickness of the hard mask layer 12 is
[0067] Specifically, under the condition of ensuring the accuracy of the photolithography process, the hard mask layer 12 may also have other suitable thicknesses according to actual process requirements.
[0068] Specifically, the mask-like layer 13 and the hard mask layer 12 have good bonding force, and the mask-like layer 13 and the substrate 1 should also have a high etching selectivity ratio.
[0069] As an example, the material of the mask-like layer 13 includes aluminum nitride, silicon carbon nitride, tantalum nitride, titanium nitride or other suitable materials. Preferably, aluminum nitride is used as the mask-like layer 13.
[0070] As an example, the thickness of the mask-like layer 13 is less than the thickness of the hard mask layer 12. Under the condition of ensuring the performance of the device, the thickness of the mask-like layer 13 can be selected according to actual conditions and is not limited here.
[0071] Specifically, the carbon-containing layer 14 is used to improve the etching selectivity in the subsequent etching process, while reducing the reflection and standing wave effect of light, thereby improving the accuracy of the photolithography process.
[0072] As an example, the thickness of the carbon-containing layer 14 ranges from Preferably, the thickness of the carbon-containing layer 14 is
[0073] Specifically, under the condition of ensuring the photolithography process accuracy, the carbon-containing layer 14 may also have other suitable thickness values according to process requirements.
[0074] Specifically, the carbon-containing layer 14 is usually a polymer with a high carbon content, and the method of forming the carbon-containing layer 14 includes spin coating or other suitable methods. Preferably, the carbon-containing layer 14 is formed on the upper surface of the mask-like layer 13 by spin coating.
[0075] Specifically, the intermediate anti-reflection layer 15 is usually a bottom anti-reflection organic coating, which is used to reduce light reflection during the photolithography process and improve the clarity and accuracy of the photolithography pattern.
[0076] Specifically, the method for forming the intermediate anti-reflection layer 15 includes spin coating or other suitable methods. Preferably, the intermediate anti-reflection layer 15 is formed on the upper surface of the carbon-containing layer 14 by spin coating.
[0077] As an example, the thickness of the intermediate anti-reflection layer 15 is in the range of Preferably, the thickness of the intermediate anti-reflection layer 15 is
[0078] Specifically, under the condition of ensuring the accuracy of the photolithography process, the thickness of the intermediate anti-reflection layer 15 can also be selected to other suitable thicknesses according to actual process requirements.
[0079] Specifically, Figure 4 As shown, it is a schematic diagram of the cross-sectional structure after the patterned shielding layer 16 is formed. The formation of the patterned shielding layer 16 includes the following steps: forming a shielding layer 16 of a preset thickness on the upper surface of the intermediate anti-reflection layer 15; exposing the shielding layer 16 based on a mask, and developing the exposed shielding layer 16 to obtain the patterned shielding layer 16.
[0080] Specifically, the shielding layer 16 is a photoresist layer, and the method of forming the shielding layer 16 on the upper surface of the intermediate anti-reflection layer 15 includes spin coating or other suitable methods.
[0081] Specifically, under the condition of ensuring the quality of the pattern formed in the shielding layer 16, the thickness of the shielding layer 16 can be selected according to actual conditions, and is not limited here.
[0082] Specifically, the photomask is a photomask produced based on the pattern to be etched, and its thickness, size, material and pattern shape are related to the actual process requirements and are not limited here; the wavelength of the light beam for exposing the shielding layer 16 is related to the actual process and is not repeated here; the method for developing the shielding layer 16 after exposure is related to the material of the shielding layer 16 and is not limited here.
[0083] Specifically, Figure 5 , which is a schematic diagram of the cross-sectional structure after forming the first groove 2, the method of forming the first groove 2 based on the patterned shielding layer 16 includes dry etching or other suitable methods. Preferably, the intermediate anti-reflection layer 15 and the carbon-containing layer 14 are etched respectively by dry etching to transfer the pattern in the shielding layer 16 to the intermediate anti-reflection layer 15 and the carbon-containing layer 14, and at the same time obtain the first groove 2 with better morphology.
[0084] Specifically, the method of removing the shielding layer 16 includes dry etching, wet stripping or other suitable methods.
[0085] Specifically, Figure 6 As shown, it is a schematic diagram of the cross-sectional structure after thinning the carbon-containing layer 14. The method for removing the intermediate anti-reflection layer 15 includes chemical mechanical grinding, dry etching, wet etching or other suitable methods; the method for thinning the carbon-containing layer 14 includes chemical mechanical grinding, dry etching or other suitable methods.
[0086] Specifically, the method for removing the intermediate anti-reflection layer 15 may be the same as the method for thinning the carbon-containing layer 14 , or may be different.
[0087] Specifically, the carbon-containing layer 14 is thinned to improve the accuracy of subsequently transferring the pattern to the hard mask layer 12. While ensuring the quality of the pattern subsequently transferred to the hard mask layer 12, the thickness of the thinned carbon-containing layer 14 can be selected according to actual conditions and is no longer limited here.
[0088] Please see again Figures 7 to 9 , perform step S4 and step S5: based on the first groove 2 in the remaining carbon-containing layer 14, form a second groove 3 penetrating the mask-like layer 13 and the hard mask layer 12, and remove the remaining carbon-containing layer 14; based on the second groove 3, etch the buffer layer 11 and the substrate 1 to obtain a third groove 4 located in the substrate 1.
[0089] Specifically, in the process of forming the second groove 3, the method of etching the mask-like layer 13 includes dry etching, wet etching or other suitable methods; the method of etching the hard mask layer 12 includes dry etching, wet etching or other suitable methods. Preferably, dry etching is used to etch the mask-like layer 13 and the hard mask layer 12 in sequence.
[0090] As an example, during the process of forming the second trench 3 , the etching gas used to etch the mask-like layer 13 is different from the etching gas used to etch the hard mask layer 12 .
[0091] As an example, Figure 7 , which is a schematic diagram of the cross-sectional structure after removing the remaining carbon-containing layer 14, and the method for removing the remaining carbon-containing layer 14 includes dry etching, wet etching or other suitable methods. Preferably, an ashing process (a type of dry etching) is used to remove the remaining carbon-containing layer 14 on the upper surface of the mask-like layer 13 after forming the second groove 3.
[0092] Specifically, since the carbon content in the carbon-containing layer 14 is relatively high, the remaining carbon-containing layer 14 on the upper surface of the mask-like layer 13 can be removed more cleanly through the ashing process, thereby avoiding the presence of remnants of the carbon-containing layer 14 on the upper surface of the mask-like layer 13.
[0093] As an example, Figure 8 , which is a schematic diagram of the cross-sectional structure after the buffer layer 11 at the bottom of the second groove 3 is removed, and the method for removing the buffer layer 11 at the bottom of the second groove 3 includes isotropic dry etching or other suitable methods. Preferably, the buffer layer 11 at the bottom of the second groove 3 is etched by isotropic dry etching to completely remove the buffer layer 11 at the bottom of the second groove 3, and at the same time, the opening size at the buffer layer 11 is enlarged compared with the size of the bottom of the second groove 3, so as to ensure the quality of the third groove 4 formed subsequently.
[0094] As an example, during etching of the buffer layer 11 at the bottom of the second trench 3 , the etching selectivity between the mask-like layer 13 and the buffer layer 11 is greater than the etching selectivity between the hard mask layer 12 and the buffer layer 11 .
[0095] Specifically, when the buffer layer 11 at the bottom of the second groove 3 is etched by an isotropic dry etching process, the mask-like layer 13 has a high etching selectivity relative to the buffer layer 11, so that the thickness of the mask-like layer 13 is only slightly thinned. The masking of the mask-like layer 13 avoids the loss of the thickness of the hard mask layer 12, thereby ensuring the thickness of the stacked structure formed by the hard mask layer 12 and the mask-like layer 13.
[0096] Specifically, Fig. 9 As shown, it is a schematic diagram of the cross-sectional structure after forming the third groove 4. The method of etching the substrate 1 includes dry etching, wet etching or other suitable methods. Since dry etching has good anisotropic etching characteristics, a groove with a relatively steep sidewall can be obtained. Preferably, the substrate 1 is etched by a dry etching process.
[0097] Specifically, in the process of etching the substrate 1, hydrogen bromide (HBr) or chlorine (Cl2) is usually required in the etching gas, and in the etching gas atmosphere containing hydrogen bromide or chlorine, the etching selectivity ratio between the mask-like layer 13 and the substrate 1 is greater than the etching selectivity ratio between the hard mask layer 12 and the substrate 1, resulting in the entire etching process, the mask-like layer 13 has only a slight thickness loss, and due to the masking of the mask-like layer 13, the thickness of the hard mask layer 12 will not be lost, so that the thickness of the stacked structure formed by the hard mask layer 12 and the mask-like layer 13 is guaranteed, thereby improving the quality of the formed third groove 4.
[0098] Specifically, under the condition of ensuring the performance of the semiconductor device to be manufactured subsequently, the depth of the third trench 4 can be selected according to the actual situation and is not limited here. The depth here refers to the distance between the bottom surface of the third trench 4 and the upper surface of the substrate 1.
[0099] Specifically, the third trench 4 can be used to manufacture high-K dielectric gate devices and polysilicon gate devices with a process of 45nm and above, for example, it can be a 45 / 40nm process node, a 32 / 28nm process node, a 22 / 20nm process node and a process node less than or equal to 16nm.
[0100] Specifically, after forming the third trench 4 , the method further includes removing the quasi-mask layer 13 , the hard mask layer 12 and the buffer layer 11 .
[0101] Specifically, the method of removing the mask-like layer 13 includes chemical mechanical grinding, dry etching, wet etching or other suitable methods; the method of removing the hard mask layer 12 includes chemical mechanical grinding, dry etching, wet etching or other suitable methods; the method of removing the buffer layer 11 includes dry etching, wet etching or other suitable methods.
[0102] Specifically, a mask-like layer 13 is formed on the upper surface of the hard mask layer 12, and the etching selectivity between the mask-like layer 13 and the buffer layer 11 and the substrate 1 is greater than the etching selectivity between the hard mask layer 12 and the buffer layer 11 and the substrate 1, so that in the process of forming the third groove 4, the thickness of the mask-like layer 13 is only slightly lost, and due to the masking of the mask-like layer 13, the loss of the thickness of the hard mask layer 12 is avoided, thereby ensuring the thickness of the stacked structure formed by the hard mask layer 12 and the mask-like layer 13, thereby improving the quality of the third groove 4 manufactured.
[0103] Specifically, due to the use of the mask-like layer 13, the process capability is optimized, so that the obtained third trench 4 can be applied to the manufacture of high-K dielectric gate and polysilicon gate devices with a process of 45nm and above, expanding the application range of the trench.
[0104] In summary, the method for making the groove of the present invention forms a mask-like layer on the upper surface of the hard mask layer by improving the lithography process of the groove, and the etching selectivity between the mask-like layer and the buffer layer and the substrate is greater than the etching selectivity between the hard mask layer and the buffer layer and the substrate. When forming the third groove, due to the masking of the mask-like layer, the loss of the thickness of the hard mask layer is avoided, and in the process of forming the third groove, the thickness of the mask-like layer is only slightly lost, so that the thickness of the stacked structure composed of the hard mask layer and the mask-like layer is guaranteed, and the quality of the third groove obtained is improved, so that the third groove can be applied to semiconductor devices with process nodes above 45nm, and the application range of the groove is expanded. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.
[0105] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.
Claims
1. A method for making a groove, It is characterized in that The following steps are involved: Providing a substrate, and forming a buffer layer, a hard mask layer, a mask-like layer, a carbon-containing layer and an intermediate anti-reflection layer stacked in sequence on the upper surface of the substrate; forming a patterned shielding layer on the upper surface of the intermediate anti-reflection layer, and forming a first groove penetrating the intermediate anti-reflection layer and the carbon-containing layer based on the patterned shielding layer; removing the shielding layer and the intermediate anti-reflection layer in sequence, and thinning the carbon-containing layer; forming a second groove penetrating the mask-like layer and the hard mask layer based on the first groove in the remaining carbon-containing layer, and removing the remaining carbon-containing layer; The buffer layer and the substrate are etched based on the second trench to obtain a third trench located in the substrate.
2. The method for making a groove according to claim 1, Features: The material of the hard mask layer includes silicon nitride.
3. The method for making a groove according to claim 1, Features: The material of the mask-like layer includes aluminum nitride, silicon carbon nitride, tantalum nitride, and titanium nitride.
4. The method for making a groove according to claim 1, Features: The thickness of the mask-like layer is smaller than the thickness of the hard mask layer.
5. The method for making a groove according to claim 1, Features: The thickness of the carbon-containing layer is in the range of The thickness of the intermediate anti-reflection layer is in the range of 6. The method for making a groove according to claim 1, Features: Methods for removing the intermediate anti-reflection layer include chemical mechanical grinding, dry etching, and wet etching; methods for thinning the carbon-containing layer include chemical mechanical grinding, dry etching, and wet etching.
7. The method for making a groove according to claim 1, Features: During the process of forming the second trench, an etching gas for etching the mask-like layer is different from an etching gas for etching the hard mask layer.
8. The method for making a groove according to claim 1, Features: Methods for removing the remaining carbon-containing layer include dry etching and wet etching.
9. The method for making a groove according to claim 1, Features: The method of etching the buffer layer at the bottom of the second trench includes isotropic dry etching.
10. The method for making a groove according to claim 1, Features: In a process of etching the buffer layer at the bottom of the second trench, an etching selectivity ratio between the mask-like layer and the buffer layer is greater than an etching selectivity ratio between the hard mask layer and the buffer layer.