Processing method for preparing silicon fin through full-dry method, silicon fin and application
The method of preparing silicon fins through the full dry method, using SAM dry photoresist and helium ion beam direct writing technology, the problems of easy introduction of contamination and low accuracy in silicon fin preparation in the prior art are solved, and high-quality and low-pollution silicon fin preparation is achieved.
Patent Information
- Application Number
- CN202510243643.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2025-06-24
AI Technical Summary
The prior art is prone to inducing contamination when preparing silicon fins, which have problems of defects and low accuracy.
The method of preparing silicon fins by a full dry method includes growing a SAM dry photoresist layer on one side of the silicon dioxide layer of the silicon substrate, exposing the exposure process using helium ion beam direct writing, and then processing and etching with ultraviolet ozone and HF, removing the photoresist layer, and finally obtaining a silicon fin structure with an exposure pattern.
This method effectively reduces the introduction of pollution during the preparation process, improves the quality and accuracy of silicon fins, reduces the pollution to the environment, and reduces the preparation cost.
Smart Images
Figure CN120201738A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular, to a processing method for preparing silicon fins by a fully dry process. Background Art
[0002] Silicon fins are the core structure of fin field-effect transistors (Fin FETs), playing a key role in chip manufacturing and supporting the advantages of chips in aspects such as low power consumption, high integration, and high performance. In advanced processes, the nano-patterned structure of silicon fins is achieved through deep ultraviolet lithography / extreme ultraviolet lithography (DUV / EUV) technology, which has certain limitations, mainly including the following four aspects:
[0003] 1) In terms of the film formation method of photoresist, the traditional DUV / EUV lithography technology uses a solution-based wet photoresist, which forms a film on the substrate by spin coating. During the exposure and baking processes of the wet photoresist, there are problems such as component diffusion (such as photoacid generators), which directly affect the pattern resolution and line edge roughness. In addition, the disadvantages of wet photoresists include uneven film thickness, high storage requirements, high costs, and high processing fees.
[0004] 2) In terms of equipment requirements, the preparation of silicon fins in advanced processes requires the use of precision DUV / EUV lithography machines, which are highly dependent on high-end equipment. DUV / EUV lithography machines have complex structures, and foreign countries strictly restrict the export of equipment, software, and upstream materials.
[0005] 3) In the patterning step, since the feature size of silicon fins in advanced processes is lower than the exposure accuracy of DUV / EUV lithography machines, self-alignment or multi-step patterning (such as two-step patterning) methods need to be used, and the steps are cumbersome.
[0006] 4) The existing processes are prone to introducing contamination during the patterning process, reducing the yield. For example, contamination is easily introduced during the spin coating film formation process of photoresist and during the liquid phase development process.
[0007] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention
[0008] In view of the above deficiencies of the existing technology, the purpose of the present invention is to provide a processing method, silicon fins, and applications for preparing silicon fins by a fully dry process, aiming to solve the problems of easy introduction of contamination, defects, and low precision when preparing silicon fins by the existing methods.
[0009] The technical solution of the present invention is as follows:
[0010] A processing method for preparing silicon fins by a fully dry process includes the steps:
[0011] A SAM dry photoresist layer is grown on one side of the silicon dioxide layer of the silicon substrate;
[0012] The SAM dry photoresist layer is exposed by helium ion beam direct writing to form an exposure pattern on the SAM dry photoresist layer;
[0013] After the exposure pattern is treated with ultraviolet ozone, the silicon dioxide layer is etched with HF, and then the SAM dry photoresist layer is removed by plasma gas to obtain a silicon dioxide layer with the exposure pattern on the silicon substrate;
[0014] Based on the silicon dioxide layer with the exposure pattern, the silicon substrate is etched, and the silicon dioxide layer is removed with HF to obtain a silicon fin structure.
[0015] The above-mentioned all-dry process for preparing silicon fins, wherein the SAM dry photoresist layer is made of SAM dry photoresist material; the structure of the SAM dry photoresist material includes an anchoring group and a terminal group; the anchoring group includes one or more of silane, thiol, and phosphoric acid; the terminal group includes a functional group containing one or more of an alkyl chain, a perfluoroalkyl chain, an aromatic group, an epoxy group, a carbon-carbon double bond, and a carbon-oxygen double bond.
[0016] The above-mentioned all-dry process for preparing silicon fins, wherein the thickness of the silicon dioxide layer is 0.1 nm - 100 nm.
[0017] The above-mentioned all-dry process for preparing silicon fins, wherein the SAM dry photoresist layer is grown by a gas phase method; the temperature of the gas phase method is 40°C - 300°C, and the pressure range of the gas phase method is 1×10 -5 bar - 1 bar.
[0018] The above-mentioned all-dry process for preparing silicon fins, wherein the line width of the exposure pattern is 0.25 nm - 1 mm.
[0019] The above-mentioned all-dry process for preparing silicon fins, wherein the voltage of the exposure treatment is 1 kV - 300 kV, the current of the exposure treatment is 0.1 pA - 20 pA, and the exposure dose of the exposure treatment is 1×10 -2 μC / cm 2 -1×10 5 μC / cm 2 。
[0020] The above-mentioned all-dry process for preparing silicon fins, wherein the etching gas for etching the silicon substrate includes one or more of SF6, O2, Cl2, BCl3, Ar, and CHF3.
[0021] The processing method for preparing silicon fins by the all-dry process, wherein the parameters for etching the silicon substrate include: the flow rate of the etching gas is not higher than 150 sccm, the source power is not higher than 600 W, and the bias power is not higher than 300 W.
[0022] A silicon fin structure is obtained by using the processing method for preparing silicon fins by the all-dry process.
[0023] An application of a silicon fin structure in a fin field-effect transistor.
[0024] Beneficial effects: The present invention provides a processing method for preparing silicon fins by the all-dry process, a silicon fin, and an application. The processing method for preparing silicon fins by the all-dry process includes the steps of: growing a SAM dry photoresist layer on one side of the silicon dioxide layer of the silicon substrate; performing an exposure process on the SAM dry photoresist layer by using helium ion beam direct writing to form an exposure pattern on the SAM dry photoresist layer; after processing the exposure pattern by using ultraviolet ozone, etching the silicon dioxide layer by using HF, and then removing the SAM dry photoresist layer by using a plasma gas to obtain a silicon dioxide layer with the exposure pattern on the silicon substrate; based on the silicon dioxide layer with the exposure pattern, etching the silicon substrate and removing the silicon dioxide layer by using HF to obtain a silicon fin structure. The present invention uses a gas-phase film-forming method to prepare a highly uniform photoresist layer on one side of the silicon dioxide layer. Compared with traditional wet photoresists, the advantages of SAM dry photoresists are that they do not contain photoacid generators, do not need to consider the component diffusion problem of materials, and the prepared photoresist layer is thin, uniform, and has a low preparation cost. At the same time, its potential resolution is higher, and at the same time, a lower line edge roughness can be achieved. In addition, helium ion beam direct writing is used for exposure to improve the processing accuracy, and at the same time, it can effectively solve the dependence on DUV / EUV lithography equipment for high-quality silicon fins and the problem of cumbersome patterning steps. In addition, the film-forming and patterning processes of SAM are both prepared in a vacuum environment, effectively reducing the pollution introduced during the preparation process, reducing defects, improving the production yield of products, and at the same time saving reagents and reducing environmental pollution. Description of the Drawings
[0025] Figure 1 It is a process flow diagram of a processing method for preparing silicon fins by the all-dry process according to the present invention;
[0026] Figure 2 It is a process flow diagram of preparing silicon fins by the all-dry process in Example 1;
[0027] Figure 3 It is the surface morphology of the SAM dry photoresist prepared in Example 1;
[0028] Figure 4 It is the exposure dose distribution diagram in Example 1;
[0029] Figure 5 Result diagram of silicon fin preparation in Example 1;
[0030] Figure 6 For Figure 5 Si etching depth diagram corresponding to contour tangent 1 in
[0031] Figure 7 For Figure 5 Si etching depth diagram corresponding to contour tangent 2 in
[0032] Figure 8 Diagram of the change of silicon fin etching depth with exposure dose in Example 1;
[0033] Figure 9 Exposure dose distribution diagram in Example 2;
[0034] Figure 10 Result diagram of silicon fin preparation in Example 2;
[0035] Figure 11 Exposure dose distribution diagram in Example 3;
[0036] Figure 12 Result diagram of silicon fin preparation in Example 3;
[0037] Figure 13 Exposure dose distribution diagram in Example 4;
[0038] Figure 14 Result diagram of silicon fin preparation in Example 4;
[0039] Figure 15 For Figure 14 Si etching depth diagram corresponding to contour tangent 3 in Detailed implementation manners
[0040] The present invention provides a fully dry processing method for preparing silicon fins, silicon fins and applications. To make the objectives, technical solutions and effects of the present invention clearer and more definite, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0041] Those skilled in the art of the present technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those of ordinary skill in the art to which the present invention belongs. It should also be understood that those terms defined in a general dictionary, should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined as herein.
[0042] As shown Figure 1 in the figure, the present invention provides a processing method for preparing silicon fins by a fully dry process, including the steps of:
[0043] Step S10: Growing a SAM dry photoresist layer on one side of the silicon dioxide layer of the silicon substrate;
[0044] Step S20: Performing an exposure process on the SAM dry photoresist layer by helium ion beam direct writing to form an exposure pattern on the SAM dry photoresist layer;
[0045] Step S30: After processing the exposure pattern with ultraviolet ozone, etching the silicon dioxide layer with HF, and then removing the SAM dry photoresist layer with plasma gas to obtain a silicon dioxide layer with the exposure pattern on the silicon substrate;
[0046] Step S40: Based on the silicon dioxide layer with the exposure pattern, etching the silicon substrate and removing the silicon dioxide layer with HF to obtain a silicon fin structure.
[0047] In this embodiment, a highly uniform photoresist layer is prepared on one side of the silicon dioxide layer by a gas-phase film-forming method. Compared with traditional wet photoresists, the advantages of SAM dry photoresists are that they do not contain photoacid generators, do not need to consider the problem of component diffusion of materials, and the prepared photoresist layer is thin, uniform, and low in preparation cost. At the same time, its potential resolution is higher, and lower line edge roughness can be achieved. Moreover, helium ion beam direct writing is used for exposure to improve the processing accuracy, and at the same time, it can effectively solve the dependence on DUV / EUV lithography equipment for high-quality silicon fins and the problem of cumbersome patterning steps. In addition, the film-forming and patterning processes of SAM are both prepared in a vacuum environment, effectively reducing the pollution introduced during the preparation process, reducing defects, improving the production yield of products, and at the same time saving reagents and reducing environmental pollution.
[0048] Specifically, in the present invention, a gas-phase method is used to grow a SAM dry photoresist layer, which can prepare a highly uniform and ultra-thin dry photoresist layer, and can prepare a high-quality dry photoresist film without surface topography defects. Then, helium ion beam is used to expose the SAM, and two pattern transfers are carried out to prepare a silicon fin structure with sub-10nm precision. Moreover, using SiO2 as a mask and etching gas to etch the silicon substrate can achieve a high etching selectivity, thus increasing the etching depth of the silicon fin structure. In particular, the high-precision nanomachining mainly stems from the following reasons: the SAM dry photoresist layer has an ultra-thin thickness, so the interaction volume with the exposure energy beam is small; the SAM dry photoresist layer does not contain photoacid generators, so there is no need to consider the influence of photoacid diffusion on the pattern size; and, the beam spot of the helium ion beam is theoretically not less than 0.25nm, which is suitable for high-precision image processing. In a suitable operating space, a silicon fin structure with nano-scale and uniform etching depth can be achieved.
[0049] The SAM dry photoresist layer is made of SAM dry photoresist material; the structure of the SAM dry photoresist material includes an anchoring group and a terminal group; the anchoring group includes one or more of silane, thiol, and phosphoric acid; the terminal group includes a functional group containing one or more of an alkyl chain, a perfluoroalkyl chain, an aromatic group, an epoxy group, a carbon-carbon double bond, and a carbon-oxygen double bond.
[0050] In some embodiments, the material of the photoresist is a self-assembled monolayer (SAM) material. The material of the SAM dry photoresist layer includes one or more of silane materials, thiol materials, and phosphoric acid group materials; the silane materials include one of OTS (octadecyltrichlorosilane), FDTS (1H,1H,2H,2H-perfluorodecyltrichlorosilane), and PTS (phenyltrichlorosilane). Compared with traditional wet photoresists, the photoresist layer of the above materials does not contain photoacid generators, does not need to consider the component diffusion problem of the material, and the prepared photoresist layer has a thin thickness, is uniform, and has a low preparation cost. At the same time, its potential resolution is higher, and a lower line edge roughness can be achieved. Moreover, the photoresist layer of the above materials can be prepared by a gas-phase method.
[0051] In a preferred embodiment, the material of the SAM dry photoresist layer is OTS, its anchoring group is silane, and the terminal group is an alkyl chain.
[0052] In some embodiments, the thickness of the silicon dioxide layer is 0.1nm - 100nm. The etching resistance of the SAM dry photoresist is weak. Using the silicon dioxide with the above thickness as a mask for Si etching can improve the etching selectivity and increase the etching depth of the silicon fin.
[0053] In a preferred embodiment, the thickness of the silicon dioxide layer is 4.2nm.
[0054] In some embodiments, the SAM dry photoresist layer is grown by a vapor phase method; the temperature of the vapor phase method is 40°C - 300°C, and the pressure range of the vapor phase method is 1×10 -5 bar - 1 bar. Growing the SAM dry photoresist layer by the vapor phase method can prepare a highly uniform and ultrathin dry photoresist film. Too high or too low temperature and pressure will affect the evaporation and deposition processes of the SAM material.
[0055] In a preferred embodiment, the temperature of the vapor phase method is 160°C, and the pressure of the vapor phase method is 0.02 bar. Under these temperature and pressure conditions, a SAM dry photoresist layer with no surface topography defects and high uniformity can be prepared.
[0056] Specifically, a silicon substrate with a silica layer treated by oxygen plasma and the SAM dry photoresist material are placed together in a glass petri dish, and then prepared in a high-temperature vacuum reaction vessel to obtain a SAM dry photoresist layer on one side of the silica layer. Adding the glass petri dish can effectively avoid the influence brought by the contamination of the side wall of the reaction chamber, thereby avoiding the defects generated during the SAM film formation process and preparing a high-quality dry photoresist film with no surface topography defects.
[0057] In some embodiments, the step S10 of growing the SAM dry photoresist layer is carried out in a vacuum oven or a device that can heat and evacuate simultaneously, such as a vacuum tube furnace, etc.; and the glass petri dish during the vapor growth process can be replaced by other vessels, such as a beaker, etc.
[0058] In some embodiments, the line width of the exposure pattern is 0.25 nm - 1 mm.
[0059] In some embodiments, the voltage of the exposure treatment is 1 kV - 300 kV, the current of the exposure treatment is 0.1 pA - 20 pA, and the exposure dose of the exposure treatment is 1×10 -2 μC / cm 2 -1×10 5 μC / cm 2 . Too low a dose will result in insufficient exposure, affecting the subsequent pattern transfer step. Too large an exposure dose is likely to introduce defects such as carbon deposition and micro-nano bubbles.
[0060] In a preferred embodiment, the voltage of the exposure treatment is 30 kV, the current of the exposure treatment is 0.5 pA, and the exposure dose of the exposure treatment is 60 - 100 μC / cm 2 . The exposure dose in this operating space can be used to prepare a uniform silicon fin structure. And with different dry photoresist materials, the range of the exposure dose will also change.
[0061] In some embodiments, the etching gas for etching the silicon substrate includes one or more of SF6, O2, Cl2, BCl3, Ar, and CHF3.
[0062] In some embodiments, the parameters for etching the silicon substrate include: the etching gas flow rate is not higher than 150 sccm, the source power is not higher than 600 W, and the bias power is not higher than 300 W. Excessive gas flow rate or power is likely to cause problems such as too fast etching rate and poor etching uniformity.
[0063] In a preferred embodiment, the etching of the silicon substrate is preferably carried out with an SF6 gas flow rate of 45 sccm, an O2 gas flow rate of 5 sccm, a source power of 50 W, and a bias power of 20 W. SF6 and O2 can achieve a high etching selectivity ratio and can increase the etching depth of the silicon fin structure.
[0064] In some embodiments, in the step S30, the HF for etching the silicon dioxide layer includes HF gas, HF solution (a solution containing HF in its components), and preferably HF gas.
[0065] In some embodiments, the plasma gas is oxygen plasma.
[0066] In some embodiments, in the step S20, the lithography techniques for exposing the SAM dry photoresist layer include helium ion beam direct writing, ultraviolet lithography, deep ultraviolet lithography, extreme ultraviolet lithography, electron beam exposure, metastable neutral atom exposure, etc., and preferably helium ion beam direct writing.
[0067] In some embodiments, the process for etching the silicon substrate includes dry etching processes such as ICP and reactive ion etching (RIE), and preferably ICP.
[0068] In addition, the present invention also provides a silicon fin structure, which is obtained by using a processing method for preparing silicon fins by a fully dry process.
[0069] In this embodiment, a highly uniform photoresist layer is prepared on one side of the silicon dioxide layer by means of vapor deposition. Compared with traditional wet photoresists, the advantage of SAM dry photoresists is that they do not contain photoacid generators, do not need to consider the problem of component diffusion of materials, and the prepared photoresist layer is thin, uniform, and low in preparation cost. At the same time, its potential resolution is higher, and lower line edge roughness can be achieved. Moreover, helium ion beam direct writing is used for exposure to improve the processing accuracy, and at the same time, the dependence on DUV / EUV lithography equipment for high-quality silicon fins and the cumbersome patterning steps can be effectively solved. In addition, the film formation and patterning processes of SAM are both prepared in a vacuum environment, effectively reducing the pollution introduced during the preparation process, reducing defects, improving the production yield of products, and at the same time saving reagents and reducing environmental pollution.
[0070] In addition, an application of a silicon fin structure in a fin field effect transistor.
[0071] In this embodiment, compared with the traditional process, the full-dry method for preparing silicon fins has the following advantages:
[0072] 1) Select a vapor-phase photoresist; the liquid-phase photoresist is used to prepare silicon fins in the prior art, and the dry photoresist grown by the vapor-phase method is used in the present invention. The advantages are as follows: the thickness of the dry photoresist is uniform and controllable; the thickness is thin, and the interaction volume with the exposure energy beam is small; it does not contain photoacid generators, and there is no need to consider the influence of photoacid diffusion on the pattern size, etc.
[0073] 2) Helium ion beam direct writing exposure; high-end DUV / EUV equipment is required to prepare sub-10nm-sized silicon fin structures in the current technology, and the steps are cumbersome. The present invention effectively solves the dependence on DUV / EUV equipment for high-precision silicon fin structures and the cumbersome steps.
[0074] 3) Double-layer mask structure; a double-layer mask is used in the present invention, namely SAM dry photoresist and SiO2. The organic layer is transferred to the inorganic oxide layer and then to the inorganic Si layer. Using SiO2 as the mask for Si etching can improve the etching selectivity and increase the etching depth of the silicon fins.
[0075] 4) Vacuum preparation; steps S10 to S40 are all prepared in a vacuum, so the defects generated during the patterning process can be greatly reduced.
[0076] The following further gives examples to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all belong to the protection scope of the present invention.
[0077] Example 1
[0078] In this embodiment, a silicon fin is prepared by a fully dry process, and the process flow schematic diagram is as Figure 2 shown, and the specific steps are as follows:
[0079] In this embodiment, the SiO2 / Si substrate treated by oxygen plasma (150 W, 5 min) and the SAM dry photoresist material (100 μL) are first placed together in a glass petri dish; then the glass petri dish is placed in a reaction vessel under high-temperature vacuum (160 °C, 0.02 bar), and wait for the reaction for 10 minutes to complete the gas-phase preparation of the SAM dry photoresist.
[0080] The surface morphology of the prepared SAM dry photoresist is as Figure 3 shown. It can be seen that the surface roughness of the SAM dry photoresist is extremely low at 0.12 nm. This is because the addition of the glass petri dish can effectively avoid the influence brought by the sidewall contamination of the reaction chamber, thereby avoiding the defects generated during the SAM film formation process and preparing a dry photoresist film with high quality and no surface morphology defects.
[0081] Based on the high-quality SAM dry photoresist, a pattern size of 500 nm × 1 μm is set, and helium ion beam exposure is carried out. The voltage and current of the helium ion beam are 30 kV and 0.5 pA respectively, and the exposure doses are 2, 4, 6, 8, 10, 20, 40, 60, 80, 100 μC / cm 2 , a total of 10 kinds, and the distribution of the exposure doses is as Figure 4 shown. After exposure, it is first treated with UV / Ozone, and then the SiO2 is etched and the SAM dry photoresist is removed by using HF and oxygen plasma respectively. Then, Si is etched using SiO2 as a mask, and SiO2 is etched using HF to complete the preparation of the silicon fin structure.
[0082] The etching parameters used for Si etching are an SF6 gas flow rate of 45 sccm, an O2 gas flow rate of 5 sccm, a source power of 50 W, and a bias power of 20 W. The result of the silicon fin preparation is as Figure 5 shown. Figure 5 The height maps corresponding to the contour tangents 1 and 2 in Figure 6 and 7 are shown. The variation of the silicon fin etching depth with the exposure dose is as Figure 8 shown, showing the operating space of the exposure dose. As can be seen from Figures 6 - 8 , as the exposure dose increases, the Si etching depth gradually increases, and when the exposure dose reaches 60 μC / cm 2 , the etching depth reaches saturation. It can be understood that too low a dose will result in insufficient exposure, affecting the subsequent pattern transfer step. In the present invention, the operating space of the exposure dose is 60 - 100 μC / cm 2。The exposed pattern obtained in this operation space is then used to etch SiO2 with the exposed pattern as a mask, and Si is etched with SiO2 as a mask, enabling an etching depth of 22 nm.
[0083] Example 2
[0084] In this example, silicon fin structures are fabricated with different line widths.
[0085] For patterns with a size of 250 nm × 1 μm, the exposure dose distribution and the silicon fin processing results are respectively as Figure 9 and 10 shown. The exposure doses are 2, 4, 6, 8, 10, 20, 40, 60, 80, 100 μC / cm 2 , a total of 10 kinds.
[0086] Example 3
[0087] In this example, silicon fin structures are fabricated with different line widths.
[0088] For patterns with a size of 1 μm × 1 μm, the exposure dose distribution and the silicon fin processing results are respectively as Figure 11 and 12 shown. The exposure doses are 2, 4, 6, 8, 10, 20, 40, 60, 80, 100 μC / cm 2 , a total of 10 kinds.
[0089] Example 4
[0090] In this example, a silicon fin structure with a uniform etching depth is processed.
[0091] For patterns with a size of 500 nm × 4 μm, the exposure dose distribution and the silicon fin processing results are respectively as Figure 13 and 14 shown. The exposure dose is 100 μC / cm 2 . Figure 15 is Figure 14 the height map shown by the contour tangent 3 in Figure 15 . It can be seen that the silicon fin structure has a uniform etching depth and fewer surface defects.
[0092] In summary, a processing method, a silicon fin, and an application for preparing a silicon fin by a fully dry process provided by the present invention. The processing method for preparing a silicon fin by a fully dry process includes the steps of: growing a SAM dry photoresist layer on one side of the silicon dioxide layer of the silicon substrate; performing exposure treatment on the SAM dry photoresist layer by helium ion beam direct writing to form an exposure pattern on the SAM dry photoresist layer; after treating the exposure pattern with ultraviolet ozone, etching the silicon dioxide layer with HF, and then removing the SAM dry photoresist layer with a plasma gas to obtain a silicon dioxide layer with the exposure pattern on the silicon substrate; based on the silicon dioxide layer with the exposure pattern, etching the silicon substrate and removing the silicon dioxide layer with HF to obtain a silicon fin structure. The present invention uses a gas-phase film-forming method to prepare a highly uniform photoresist layer on one side of the silicon dioxide layer. Compared with traditional wet photoresists, the advantage of SAM dry photoresists is that they do not contain photoacid generators, do not need to consider the problem of component diffusion of materials, and the prepared photoresist layer is thin, uniform, and has a low preparation cost. At the same time, its potential resolution is higher, and lower line edge roughness can be achieved. Moreover, helium ion beam direct writing is used for exposure to improve the processing accuracy, and at the same time, it can effectively solve the dependence of high-quality silicon fins on DUV / EUV lithography equipment and the problem of cumbersome patterning steps. In addition, the film-forming and patterning processes of SAM are both prepared in a vacuum environment, effectively reducing the pollution introduced during the preparation process, reducing defects, improving the production yield of products, and at the same time saving reagents and reducing environmental pollution.
[0093] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description. All such improvements and transformations should fall within the protection scope of the appended claims of the present invention.
Claims
1. A method for preparing silicon fins by a fully dry process, characterized in that: Includes steps: Growing a SAM dry photoresist layer on one side of the silicon dioxide layer of the silicon substrate; Expose the SAM dry photoresist layer by helium ion beam direct writing to form an exposure pattern on the SAM dry photoresist layer; After treating the exposure pattern with ultraviolet ozone, etching the silicon dioxide layer with HF, and then removing the SAM dry photoresist layer with plasma gas to obtain a silicon dioxide layer with the exposure pattern on the silicon substrate; Based on the silicon dioxide layer having the exposure pattern, the silicon substrate is etched, and the silicon dioxide layer is removed by using HF to obtain a silicon fin structure.
2. The method for preparing silicon fins by a fully dry process according to claim 1, characterized in that: The SAM dry photoresist layer is made of SAM dry photoresist material; the structure of the SAM dry photoresist material includes an anchoring group and an end group; the anchoring group includes one or more of silane, thiol, and phosphoric acid; the end group includes a functional group containing one or more of an alkyl chain, a perfluoroalkyl chain, an aromatic group, an epoxy group, a carbon-carbon double bond, and a carbon-oxygen double bond.
3. The method for preparing silicon fins by a fully dry process according to claim 1, characterized in that: The thickness of the silicon dioxide layer is 0.1 nm-100 nm.
4. The method for preparing silicon fins by a fully dry process according to claim 1, characterized in that: The SAM dry photoresist layer is grown by a vapor phase method; the temperature of the vapor phase method is 40°C-300°C, and the pressure range of the vapor phase method is 1×10 - 5 bar-1bar.
5. The method for preparing silicon fins by a fully dry process according to claim 1, characterized in that: The line width of the exposure pattern is 0.25nm-1mm.
6. The method for preparing silicon fins by a fully dry process according to claim 1, characterized in that: The voltage of the exposure process is 1 kV-300 kV, the current of the exposure process is 0.1 pA-20 pA, and the exposure dose of the exposure process is 1×10 -2 μC / cm 2 -1×10 5 μC / cm 2 .
7. The method for preparing silicon fins by a fully dry process according to claim 1, characterized in that: The etching gas used to etch the silicon substrate includes one or more of SF6, O2, Cl2, BCl3, Ar, and CHF3.
8. The method for preparing silicon fins by a fully dry process according to claim 1, characterized in that: The parameters for etching the silicon substrate include: an etching gas flow rate not higher than 150 sccm, a source power not higher than 600W, and a bias power not higher than 300W.
9. A silicon fin structure, characterized in that: The silicon fin is prepared by using the fully dry method for preparing the silicon fin as described in any one of claims 1 to 8.
10. Use of the silicon fin structure according to claim 9 in a fin field effect transistor.