Method for forming semiconductor structure

Abstract

A method for forming a semiconductor structure, comprising: providing a layer to be etched; forming a plurality of core layers on the layer to be etched, with a first opening and a second opening between adjacent core layers, the width of the first opening being smaller than the width of the second opening; forming a first sacrificial material layer on the layer to be etched and on the plurality of core layers; forming a second sacrificial layer on the first sacrificial material layer in the first opening, and forming a sacrificial structure in the first opening; after forming the sacrificial structure, removing the core layer; after removing the core layer, forming a sidewall on the sidewall of the sacrificial structure, and after forming the sidewall, removing the sacrificial structure. The method simplifies the process flow and saves production costs.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a method for forming a semiconductor structure. Background Art

[0002] As the minimum line width and spacing of integrated circuit design continue to shrink, the optical resolution of the 193nm deep ultraviolet immersion lithography machine used in the photolithography process has reached its limit (its minimum spatial half-period is about 38nm). When the wavelength cannot be reduced, in order to continue to reduce the spatial half-period and increase the density of integrated circuit patterns, self-aligned multiple patterning (SAMP) technology based on mandrel and spacer processes has emerged, including self-aligned double patterning (SADP), self-aligned triple patterning (SATP), self-aligned quadruple patterning (SAQP), self-aligned sextuple patterning (SASP), etc.

[0003] However, the process of forming patterns using the existing self-aligned multi-patterning technology is relatively complicated, and requires the formation of a multi-layer stacked film structure to transfer the patterns layer by layer, resulting in a relatively lengthy process.

[0004] Therefore, there is a need for improvements in self-aligned multi-patterning techniques. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for forming a semiconductor structure to improve the self-aligned multiple patterning technology.

[0006] In order to solve the above technical problems, the technical solution of the present invention provides a method for forming a semiconductor structure, including: providing a layer to be etched; forming a plurality of core layers on the layer to be etched, with a first opening and a second opening between adjacent core layers, and the width of the first opening is smaller than the width of the second opening; forming a first sacrificial material layer on the layer to be etched and on the plurality of core layers; forming a second sacrificial layer on the first sacrificial material layer in the first opening, and forming a sacrificial structure in the first opening; after forming the sacrificial structure, removing the core layer; after removing the core layer, forming a side wall on the side wall of the sacrificial structure; after forming the side wall, removing the sacrificial structure.

[0007] Optionally, the method for forming the second sacrificial layer includes: forming a second sacrificial material layer on the surface of the first sacrificial material layer, the second sacrificial material layer filling the first opening; etching back the second sacrificial material layer until the surface of the first sacrificial material layer is exposed, forming an initial second sacrificial layer in the first opening and on the side wall surface of the second opening; removing the initial second sacrificial layer on the side wall surface of the second opening, and forming a second sacrificial layer in the first opening.

[0008] Optionally, a material of the second sacrificial material layer is different from a material of the first sacrificial material layer.

[0009] Optionally, the material of the second sacrificial material layer includes an inorganic material, and the inorganic material includes silicon oxide.

[0010] Optionally, after forming the second sacrificial layer and before removing the core layer, the method further includes: forming a first sacrificial layer on the inner wall surface of the first opening; and the sacrificial structure includes the first sacrificial layer and the second sacrificial layer located on the surface of the first sacrificial layer.

[0011] Optionally, the method for forming the first sacrificial layer includes: after forming the second sacrificial layer, etching back the first sacrificial material layer until the surface of the layer to be etched is exposed, and forming the first sacrificial layer on the side wall of the core layer.

[0012] Optionally, a material of the first sacrificial material layer is different from a material of the sidewall spacer.

[0013] Optionally, the material of the first sacrificial material layer includes a metal-containing material, and the metal-containing material includes a combination of one or more of titanium oxide and aluminum oxide; the material of the sidewall includes an amorphous material, and the amorphous material includes amorphous silicon.

[0014] The material of the sidewall spacer includes a metal-containing material, and the metal-containing material includes a combination of one or more of titanium oxide and aluminum oxide; the material of the first sacrificial material layer includes an amorphous material, and the amorphous material includes amorphous silicon.

[0015] Optionally, the method for forming the first sacrificial layer includes: after forming the second sacrificial layer, etching back the first sacrificial material layer until the surface of the layer to be etched is exposed, and forming an initial first sacrificial layer on the side wall of the core layer; after removing the core layer, modifying the initial first sacrificial layer to form the first sacrificial layer.

[0016] Optionally, the process of modifying the initial first sacrificial layer includes an ion implantation process, and the implanted ions include: carbon ions, nitrogen ions, boron ions or fluorine ions.

[0017] Optionally, the material of the first sacrificial material layer is the same as that of the sidewall spacer.

[0018] Optionally, the material of the first sacrificial material layer includes an amorphous material, and the amorphous material includes amorphous silicon; the material of the sidewall includes an amorphous material, and the amorphous material includes amorphous silicon.

[0019] Optionally, the material of the first sacrificial layer is different from the material of the core layer; the material of the second sacrificial layer is different from the material of the core layer.

[0020] Optionally, the material of the core layer includes an inorganic material, and the inorganic material includes silicon nitride.

[0021] Optionally, the method further includes: forming a first sacrificial layer on the sidewall of the second opening.

[0022] Optionally, after removing the core layer, the method further includes: forming a sidewall on the sidewall of the first sacrificial layer in the second opening; after forming the sidewall, removing the first sacrificial layer in the second opening.

[0023] Optionally, the layer to be etched includes a substrate and a transition structure located on the substrate.

[0024] Optionally, the material of the transition structure is different from the material of the first sacrificial material layer; the material of the transition structure is different from the material of the sidewall.

[0025] Optionally, the material of the transition structure includes an inorganic material, and the inorganic material includes silicon oxide.

[0026] Optionally, the first sacrificial material layer is located on the top surface and sidewall surfaces of the core layer.

[0027] Optionally, after removing the sacrificial structure, the method further includes: etching the layer to be etched using the sidewall as a mask.

[0028] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0029] The method for forming a semiconductor structure in the technical solution of the present invention forms a plurality of core layers on the layer to be etched, with a first opening and a second opening between adjacent core layers, forms a sacrificial structure in the first opening, and then forms a side wall on the side wall of the sacrificial structure. The side wall can be transmitted as a pattern of the semiconductor structure, so that there is no need to additionally form other mask structures or core structures, thereby simplifying the process flow, saving production costs, and helping to improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figures 1 to 12It is a schematic cross-sectional structure diagram of the semiconductor structure forming process in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] As described in the background art, the process of forming patterns using the existing self-aligned multiple patterning technology is relatively complicated, and the self-aligned multiple patterning technology needs to be improved.

[0032] Specifically, the self-aligned multiple patterning method forms sidewalls on both sides of the core layer by using a pre-formed photolithography pattern as the core layer, then removes the previously formed photolithography pattern by etching, and transfers the sidewall pattern to the lower material, thereby obtaining a pattern with a smaller feature size, and then repeats the above steps with the pattern formed on the lower material as the core layer, and each time the pattern density obtained is twice the density of the previous core layer pattern. This requires the formation of multiple material layers for the core layer, as well as multiple transition structures for transferring the sidewall pattern to the lower material, and the stacking of the film layers is relatively complicated.

[0033] However, the stacked film layers are relatively thick. On the one hand, as the size becomes smaller and smaller, the morphology and size accuracy of the graphics are higher. In the process of transferring the graphics layer by layer, the size accuracy and morphology of the graphics will drift to a certain extent, thus failing to meet the requirements. On the other hand, it is necessary to form a multi-layer film stack and etch layer by layer, which requires a relatively high production cost.

[0034] In order to solve the above problems, the technical solution of the present invention provides a method for forming a semiconductor structure, by forming a plurality of core layers on the layer to be etched, with a first opening and a second opening between adjacent core layers, forming a sacrificial structure in the first opening, and then forming a side wall on the side wall of the sacrificial structure, the side wall can be transmitted as a pattern of the semiconductor structure, so that there is no need to additionally form other mask structures or core structures, thereby simplifying the process flow, saving production costs, and helping to improve production efficiency.

[0035] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0036] Figures 1 to 12 It is a schematic cross-sectional structure diagram of the semiconductor structure forming process in an embodiment of the present invention.

[0037] Please refer to Figure 1 , providing a layer to be etched.

[0038] The layer to be etched includes a substrate 100 and a transition structure 101 located on the substrate 100 .

[0039] The material of the substrate 100 includes a semiconductor material or a metal material, the semiconductor material includes single crystal silicon, polycrystalline silicon, germanium, silicon germanium, gallium arsenide, silicon on insulator or germanium on insulator, etc., and the metal material includes a combination of one or more of copper, aluminum, tungsten and titanium nitride; the material of the transition structure 101 includes an inorganic material, and the inorganic material includes a combination of one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon carbonitride and silicon carbonitride oxide.

[0040] In this embodiment, the material of the substrate 100 includes single crystal silicon; the material of the transition structure 101 includes silicon oxide.

[0041] In other embodiments, the material of the substrate includes copper; the material of the transition structure includes silicon nitride, or a stack of silicon oxide and silicon nitride.

[0042] Please refer to Figure 2 , a plurality of core layers 102 are formed on the layer to be etched, and a first opening 103 and a second opening 104 are provided between adjacent core layers 102. In the direction in which the plurality of core layers 102 are arranged along the surface of the layer to be etched, a width W1 of the first opening 103 is smaller than a width W2 of the second opening 104.

[0043] The method for forming the core layer 102 includes: forming a core material layer (not shown) on the layer to be etched; forming a patterned mask layer (not shown) on the core material layer; etching the core material layer using the patterned mask layer as a mask until the surface of the layer to be etched is exposed, thereby forming the core layer 102 on the layer to be etched.

[0044] The material of the core layer 102 is different from the material of the transition structure 101 , so when the core material layer is etched to form the core layer 102 , the etching process causes less damage to the layer to be etched.

[0045] The material of the core layer 102 includes an inorganic material, and the inorganic material includes one or more combinations of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon carbide nitride, and silicon oxycarbon nitride. In this embodiment, the material of the core layer 102 includes silicon nitride.

[0046] Please refer to Figure 3 , a first sacrificial material layer 105 is formed on the layer to be etched and on the core layers 102 .

[0047] In this embodiment, the first sacrificial material layer 105 is located on the top surface and the sidewall surface of the core layer 102 .

[0048] The first sacrificial material layer 105 provides material for a first sacrificial layer to be formed subsequently.

[0049] The process of forming the first sacrificial material layer 105 includes an atomic layer deposition process, a chemical vapor deposition process or a thermal treatment process. In this embodiment, the process of forming the first sacrificial material layer 105 includes an atomic layer deposition process, which can form a first sacrificial material layer 105 with a dense structure and a relatively thin thickness.

[0050] The material of the first sacrificial material layer 105 is different from the material of the second sacrificial layer formed subsequently. Therefore, when the second sacrificial layer is subsequently formed on the surface of the first sacrificial material layer 105 in the first opening 103, the process of forming the second sacrificial layer causes less damage to the first sacrificial material layer 105. Therefore, the first sacrificial material layer 105 plays a certain protective role on the layer to be etched.

[0051] In this embodiment, the material of the first sacrificial material layer 105 is the same as the material of the spacers formed subsequently.

[0052] In this embodiment, the material of the first sacrificial material layer 105 includes an amorphous material, and the amorphous material includes amorphous silicon.

[0053] In other embodiments, the material of the first sacrificial material layer is different from the material of the spacer.

[0054] In other embodiments, the material of the first sacrificial material layer includes a metal-containing material, and the metal-containing material includes a combination of one or more of titanium oxide and aluminum oxide.

[0055] Next, a second sacrificial layer is formed on the surface of the first sacrificial material layer 105 in the first opening 103 , and a sacrificial structure is formed in the first opening 103 .

[0056] The sacrificial structure includes a first sacrificial layer and a second sacrificial layer 108 located on the surface of the first sacrificial layer. The process of forming the sacrificial structure can be referred to Figures 4 to 6 .

[0057] A second sacrificial layer 108 is formed on the surface of the first sacrificial material layer 105 in the first opening 103. The formation process of the second sacrificial layer 108 is shown in FIG. Figure 4 and Figure 5 .

[0058] Please refer to Figure 4 , forming a second sacrificial material layer (not shown) on the surface of the first sacrificial material layer 105, and the second sacrificial material layer fills the first opening 103; back-etching the second sacrificial material layer until the surface of the first sacrificial material layer 105 is exposed, and forming an initial second sacrificial layer 106 in the first opening 103 and on the sidewall surface of the second opening 104.

[0059] The material of the second sacrificial material layer is different from that of the first sacrificial material layer 105 , and the material of the second sacrificial material layer is different from that of the core layer 102 .

[0060] The material of the second sacrificial material layer is different from that of the first sacrificial material layer 105, so that the second sacrificial material layer has a larger etching selectivity ratio with the first sacrificial material layer 105, so that the process of forming the second sacrificial layer causes less damage to the first sacrificial material layer 105. The material of the second sacrificial material layer is different from that of the core layer 102, so that when the core layer 102 is subsequently removed, the process of removing the core layer 102 causes less damage to the formed second sacrificial layer, so that the pattern morphology of the sidewall formed subsequently is better.

[0061] The material of the second sacrificial material layer includes an inorganic material, and the inorganic material includes a combination of one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, silicon carbide nitride, and silicon oxycarbon nitride. The process of forming the second sacrificial material layer includes an atomic layer deposition process, a chemical vapor deposition process, or a thermal treatment process.

[0062] In this embodiment, the material of the second sacrificial material layer includes silicon oxide; and the process of forming the second sacrificial material layer includes a chemical vapor deposition process.

[0063] Please refer to Figure 5 , the initial second sacrificial layer 106 on the sidewall surface of the second opening 104 is removed, and a second sacrificial layer 108 is formed in the first opening 103 .

[0064] The method for forming the second sacrificial layer 108 includes: forming a mask layer 107 on the surface of the initial second sacrificial layer 106 in the first opening 103, the mask layer 107 exposing the initial second sacrificial layer 106 in the second opening 104; using the mask layer 107 as a mask, removing the initial second sacrificial layer 106 in the second opening 104, and forming a second sacrificial layer 108 in the first opening 103.

[0065] The process of removing the initial second sacrificial layer 106 in the second opening 104 includes a combination of one or more of a dry etching process and a wet etching process.

[0066] In this embodiment, the material of the mask layer 107 includes photoresist.

[0067] After forming the second sacrificial layer 108 , the mask layer 107 is removed.

[0068] Please refer to Figure 6 An initial first sacrificial layer 109 is formed on the inner wall surface of the first opening 103 .

[0069] The method for forming the initial first sacrificial layer 109 includes: etching back the first sacrificial material layer 105 until the surface of the to-be-etched layer is exposed, and forming the initial first sacrificial layer 109 on the sidewall of the core layer 102 .

[0070] The material of the first sacrificial material layer 105 is different from the material of the core layer 102, and the material of the first sacrificial material layer 105 is different from the material of the transition structure 101, so that the first sacrificial material layer 105 has a larger etching selectivity ratio with the core layer 102, and the first sacrificial material layer 105 has a larger etching selectivity ratio with the transition structure 101, so that the process of back-etching the first sacrificial material layer 105 causes less damage to the core layer 102 and the layer to be etched.

[0071] In this embodiment, while the initial first sacrificial layer 109 is formed on the inner wall surface of the first opening 103 , the initial first sacrificial layer 109 is also formed on the sidewall of the second opening 104 .

[0072] In this embodiment, the material of the first sacrificial material layer 105 is the same as the material of the sidewall formed subsequently, so the initial first sacrificial layer 109 needs to be modified to form a first sacrificial layer, so that the first sacrificial layer has a larger etching selectivity ratio with the sidewall, and the sacrificial structure includes a first sacrificial layer and a second sacrificial layer 108.

[0073] In other embodiments, the material of the first sacrificial material layer is different from the material of the spacer formed subsequently, so that the initial first sacrificial layer does not need to be modified, and the sacrificial structure includes the initial first sacrificial layer and the second sacrificial layer.

[0074] Please refer to Figure 7 After forming the initial first sacrificial layer 109, the core layer 102 is removed.

[0075] The process of removing the core layer 102 includes a dry etching process and a wet etching process or a combination of one or more of the above.

[0076] The material of the core layer 102 is different from that of the second sacrificial layer 108, the material of the core layer 102 is different from that of the initial first sacrificial layer 109, and the material of the core layer 102 is different from that of the transition structure 101. Therefore, when removing the core layer 102, the process of removing the core layer 102 causes less damage to the second sacrificial layer 108, the initial first sacrificial layer 109 and the layer to be etched. Therefore, when a sidewall pattern is subsequently formed on the sidewall of the initial first sacrificial layer 109, the size of the pattern is precise and the morphology is good.

[0077] Please refer to Figure 8, the initial first sacrificial layer 109 is modified to form a first sacrificial layer 110.

[0078] In this embodiment, the material of the first sacrificial material layer 105 is the same as the material of the spacer formed subsequently, so the initial first sacrificial layer 109 needs to be modified to form the first sacrificial layer 110, so that the first sacrificial layer 110 has a larger etching selectivity ratio with the spacer.

[0079] The process of modifying the initial first sacrificial layer 109 includes an ion implantation process or a doping process.

[0080] In this embodiment, the process of modifying the initial first sacrificial layer 109 includes an ion implantation process, and the implanted ions include: carbon ions, boron ions, fluorine ions or nitrogen ions.

[0081] The material of the modified first sacrificial layer 110 is different from that of the initial first sacrificial layer 109, and thus different from the material of the subsequently formed sidewalls. Therefore, the first sacrificial layer 110 has a greater etching selectivity ratio with the subsequently formed sidewalls, so that when the first sacrificial layer 110 is subsequently removed, less damage is caused to the sidewalls, so that the size of the sidewall pattern is precise and the morphology is good.

[0082] In other embodiments, the material of the first sacrificial material layer is different from the material of the spacer formed subsequently, so that the initial first sacrificial layer does not need to be modified, and the sacrificial structure includes the initial first sacrificial layer and the second sacrificial layer.

[0083] Please refer to Fig. 9 A sidewall 111 is formed on the sidewall of the sacrificial structure and the sidewall of the first sacrificial layer 110 in the second opening 104 .

[0084] The method for forming the sidewall 111 includes: forming a sidewall material layer (not shown) on the surface of the layer to be etched, the top surface and sidewall surface of the first sacrificial layer 110, and the top surface and sidewall surface of the sacrificial structure; and etching back the sidewall material layer until the surface of the layer to be etched and the top surface of the first sacrificial layer 110 are exposed to form the sidewall 111.

[0085] The material of the sidewall 111 is different from that of the first sacrificial layer 110, the material of the sidewall 111 is different from that of the second sacrificial layer 108, and the material of the sidewall 111 is different from that of the transition structure 101. Therefore, when forming the sidewall 111, the etch-back process causes less damage to the first sacrificial layer 110, the second sacrificial layer 108, and the layer to be etched, so that the formed sidewall 111 has a better morphology.

[0086] In this embodiment, the material of the spacer 111 includes an amorphous material, and the amorphous material includes amorphous silicon.

[0087] In this embodiment, the material of the spacer 111 is the same as that of the first sacrificial material layer 105 .

[0088] In other embodiments, the material of the spacer is different from the material of the first sacrificial material layer.

[0089] In other embodiments, the material of the sidewalls includes a metal-containing material, and the metal-containing material includes a combination of one or more of titanium oxide and aluminum oxide.

[0090] Next, after forming the sidewall 111, the sacrificial structure is removed. For the process of removing the sacrificial structure, please refer to Figure 10 to Figure 11 .

[0091] Please refer to Fig.10 , remove the second sacrificial layer 108 in the first opening 103 .

[0092] The method for removing the second sacrificial layer 108 in the first opening 103 includes: forming a protective layer 112 on the layer to be etched and the sidewalls of the spacer 111, wherein the protective layer 112 exposes the surface of the second sacrificial layer 108; and removing the second sacrificial layer 108 using the protective layer 112 as a mask.

[0093] The protection layer 112 can protect the surface of the transition structure 101 , so that the process of removing the second sacrificial layer 108 causes less damage to the layer to be etched.

[0094] The second sacrificial layer 108 is made of different materials from the first sacrificial layer 110 , and the second sacrificial layer 108 is made of different materials from the sidewall spacer 111 . Therefore, the process of removing the second sacrificial layer 108 causes less damage to the first sacrificial layer 110 and the sidewall spacer 111 .

[0095] The process of removing the second sacrificial layer 108 includes a dry etching process and a wet etching process or a combination of one or more of the above.

[0096] The material of the protection layer 112 includes an organic material, and the organic material includes amorphous carbon or photoresist.

[0097] Please refer to Fig.11 , the first sacrificial layer 110 in the first opening 103 and the second opening 104 is removed.

[0098] The process of removing the first sacrificial layer 110 includes a dry etching process and a wet etching process or a combination of one or more of the above.

[0099] The material of the first sacrificial layer 110 is different from that of the sidewall 111 , so when the first sacrificial layer 110 is removed, the process of removing the first sacrificial layer 110 causes less damage to the sidewall 111 , so that the formed sidewall 111 has high graphic size accuracy and good morphology.

[0100] Different processes are used to first remove the second sacrificial layer 108 and then remove the first sacrificial layer 110, so that the sacrificial structure in the first opening 103 can be completely removed, so that when the pattern of the sidewall 111 is subsequently transferred, the semiconductor structure pattern morphology formed is better.

[0101] After removing the first sacrificial layer 110 , the protection layer 112 is removed.

[0102] Please refer to Fig.12 , using the sidewall 111 as a mask, etching the layer to be etched to form a semiconductor structure 200.

[0103] The process of etching the layer to be etched includes a dry etching process, which can form a semiconductor structure 200 with good sidewall morphology.

[0104] In the method for forming the semiconductor structure, a plurality of core layers 102 are formed on the layer to be etched, a first opening 103 and a second opening 104 are provided between adjacent core layers 102, a sacrificial structure is formed in the first opening 103, and a sidewall 111 is formed on the sidewall of the sacrificial structure. The sidewall 111 can be transferred as a pattern of the semiconductor structure, so that there is no need to additionally form other mask structures or core structures, thereby simplifying the process flow, saving production costs, and helping to improve production efficiency.

[0105] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for forming a semiconductor structure, characterized in that: include: Providing a layer to be etched; Forming a plurality of core layers on the layer to be etched, wherein a first opening and a second opening are provided between adjacent core layers, and the width of the first opening is smaller than the width of the second opening; forming a first sacrificial material layer on the layer to be etched and on the plurality of core layers; forming a second sacrificial layer on the first sacrificial material layer in the first opening, and forming a sacrificial structure in the first opening, wherein the sacrificial structure comprises an initial first sacrificial layer located on the inner wall surface of the first opening and a second sacrificial layer located on the surface of the initial first sacrificial layer, and the second sacrificial layer completely fills the first opening; After forming the sacrificial structure, removing the core layer; After removing the core layer, forming a sidewall on the sidewall of the sacrificial structure; After forming the sidewalls, removing the sacrificial structure; After removing the sacrificial structure, the layer to be etched is etched using the sidewall as a mask.

2. The method for forming a semiconductor structure according to claim 1, wherein: The method for forming the second sacrificial layer includes: forming a second sacrificial material layer on the surface of the first sacrificial material layer, the second sacrificial material layer filling the first opening; etching back the second sacrificial material layer until the surface of the first sacrificial material layer is exposed, forming an initial second sacrificial layer in the first opening and on the side wall surface of the second opening; removing the initial second sacrificial layer on the side wall surface of the second opening, and forming a second sacrificial layer in the first opening.

3. The method for forming a semiconductor structure according to claim 2, wherein: The material of the second sacrificial material layer is different from that of the first sacrificial material layer.

4. The method for forming a semiconductor structure according to claim 3, wherein: The material of the second sacrificial material layer includes an inorganic material, and the inorganic material includes silicon oxide.

5. The method for forming a semiconductor structure according to claim 1, wherein: The method for forming the initial first sacrificial layer comprises: after forming the second sacrificial layer, etching back the first sacrificial material layer until the surface of the layer to be etched is exposed, and forming the initial first sacrificial layer on the side wall of the core layer.

6. The method for forming a semiconductor structure according to claim 5, wherein: The material of the first sacrificial material layer is different from that of the sidewall spacer.

7. The method for forming a semiconductor structure according to claim 6, wherein: The material of the first sacrificial material layer includes a metal-containing material, and the metal-containing material includes a combination of one or more of titanium oxide and aluminum oxide; the material of the sidewall includes an amorphous material, and the amorphous material includes amorphous silicon.

8. The method for forming a semiconductor structure according to claim 6, wherein: The material of the sidewall spacer includes a metal-containing material, and the metal-containing material includes a combination of one or more of titanium oxide and aluminum oxide; the material of the first sacrificial material layer includes an amorphous material, and the amorphous material includes amorphous silicon.

9. The method for forming a semiconductor structure according to claim 1, wherein: After removing the core layer, the method further includes: modifying the initial first sacrificial layer to form a first sacrificial layer, wherein the sacrificial structure includes a first sacrificial layer located on the inner wall surface of the first opening and a second sacrificial layer located on the surface of the first sacrificial layer.

10. The method for forming a semiconductor structure according to claim 9, wherein: The process of modifying the initial first sacrificial layer includes an ion implantation process, and the implanted ions include: carbon ions, nitrogen ions, boron ions or fluorine ions.

11. The method for forming a semiconductor structure according to claim 10, wherein: The material of the first sacrificial material layer is the same as that of the sidewall spacer.

12. The method for forming a semiconductor structure according to claim 11, wherein: The material of the first sacrificial material layer includes an amorphous material, and the amorphous material includes amorphous silicon; the material of the sidewalls includes an amorphous material, and the amorphous material includes amorphous silicon.

13. The method for forming a semiconductor structure according to claim 1, wherein: The material of the initial first sacrificial layer is different from the material of the core layer; the material of the second sacrificial layer is different from the material of the core layer.

14. The method for forming a semiconductor structure according to claim 13, wherein: The material of the core layer includes an inorganic material, and the inorganic material includes silicon nitride.

15. The method for forming a semiconductor structure according to claim 1, wherein: Also includes: The initial first sacrificial layer is formed on the sidewall of the second opening.

16. The method for forming a semiconductor structure according to claim 15, wherein: After removing the core layer, the method further includes: forming a sidewall on the sidewall of the initial first sacrificial layer in the second opening; after forming the sidewall, removing the initial first sacrificial layer in the second opening.

17. The method for forming a semiconductor structure according to claim 1, wherein: The layer to be etched includes a substrate and a transition structure located on the substrate.

18. The method for forming a semiconductor structure according to claim 17, wherein: The material of the transition structure is different from the material of the first sacrificial material layer; the material of the transition structure is different from the material of the sidewall.

19. The method for forming a semiconductor structure according to claim 18, wherein: The material of the transition structure includes an inorganic material, and the inorganic material includes silicon oxide.

20. The method for forming a semiconductor structure according to claim 1, wherein: The first sacrificial material layer is located on the top surface and the sidewall surface of the core layer.

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