WO2024016381A1 - 半导体结构及其形成方法 - Google Patents
半导体结构及其形成方法 Download PDFInfo
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- WO2024016381A1 WO2024016381A1 PCT/CN2022/109551 CN2022109551W WO2024016381A1 WO 2024016381 A1 WO2024016381 A1 WO 2024016381A1 CN 2022109551 W CN2022109551 W CN 2022109551W WO 2024016381 A1 WO2024016381 A1 WO 2024016381A1
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- film layer
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- 238000000034 method Methods 0.000 title claims abstract description 72
- 239000004065 semiconductor Substances 0.000 title claims abstract description 35
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 330
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 316
- 238000005530 etching Methods 0.000 claims abstract description 106
- 150000002500 ions Chemical class 0.000 claims abstract description 73
- 239000000758 substrate Substances 0.000 claims abstract description 45
- 238000009396 hybridization Methods 0.000 claims description 30
- -1 carbon ions Chemical class 0.000 claims description 22
- 230000015572 biosynthetic process Effects 0.000 claims description 18
- 229910052796 boron Inorganic materials 0.000 claims description 13
- 238000002347 injection Methods 0.000 claims description 9
- 239000007924 injection Substances 0.000 claims description 9
- 238000010884 ion-beam technique Methods 0.000 claims description 9
- LVZWSLJZHVFIQJ-UHFFFAOYSA-N Cyclopropane Chemical compound C1CC1 LVZWSLJZHVFIQJ-UHFFFAOYSA-N 0.000 claims description 7
- 230000005684 electric field Effects 0.000 claims description 5
- 238000002513 implantation Methods 0.000 claims description 5
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 11
- 239000003575 carbonaceous material Substances 0.000 abstract description 7
- 230000004048 modification Effects 0.000 abstract 1
- 238000012986 modification Methods 0.000 abstract 1
- 239000010408 film Substances 0.000 description 288
- 239000007789 gas Substances 0.000 description 33
- 238000000026 X-ray photoelectron spectrum Methods 0.000 description 20
- 125000004432 carbon atom Chemical group C* 0.000 description 19
- 238000005468 ion implantation Methods 0.000 description 15
- 150000001721 carbon Chemical group 0.000 description 10
- 239000001257 hydrogen Substances 0.000 description 10
- 229910052739 hydrogen Inorganic materials 0.000 description 10
- 239000000463 material Substances 0.000 description 9
- 238000010586 diagram Methods 0.000 description 6
- 238000000059 patterning Methods 0.000 description 6
- 238000000231 atomic layer deposition Methods 0.000 description 5
- 239000003574 free electron Substances 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 4
- 239000011203 carbon fibre reinforced carbon Substances 0.000 description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 229910021389 graphene Inorganic materials 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 238000012795 verification Methods 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- ZOCHARZZJNPSEU-UHFFFAOYSA-N diboron Chemical compound B#B ZOCHARZZJNPSEU-UHFFFAOYSA-N 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 238000005240 physical vapour deposition Methods 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000008521 reorganization Effects 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/308—Chemical or electrical treatment, e.g. electrolytic etching using masks
- H01L21/3081—Chemical or electrical treatment, e.g. electrolytic etching using masks characterised by their composition, e.g. multilayer masks, materials
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/308—Chemical or electrical treatment, e.g. electrolytic etching using masks
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/308—Chemical or electrical treatment, e.g. electrolytic etching using masks
- H01L21/3083—Chemical or electrical treatment, e.g. electrolytic etching using masks characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane
- H01L21/3086—Chemical or electrical treatment, e.g. electrolytic etching using masks characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3205—Deposition of non-insulating-, e.g. conductive- or resistive-, layers on insulating layers; After-treatment of these layers
Definitions
- the present disclosure relates to the field of semiconductor technology, and in particular, to a semiconductor structure and a method of forming the same.
- the patterning process is one of the important processes in the semiconductor device manufacturing process.
- a carbon film layer is often used as a hard mask in the patterning process.
- the hardness of the existing carbon film layer is small, and during the etching process, it is often Deformation due to large losses will lead to deformation of the etching window and lower product yield.
- the present disclosure provides a semiconductor structure and a forming method thereof, which can increase the hardness of the carbon film layer and improve product yield.
- a method for forming a semiconductor structure including:
- An initial carbon film layer is formed on the surface of the substrate, and the initial carbon film layer at least includes SP 2 hybridization bonds;
- the hardness of the target carbon film layer is greater than the hardness of the initial carbon film layer.
- the etching selectivity of the target carbon film layer is higher than the etching selectivity of the initial carbon film layer.
- an initial carbon film layer is formed on the surface of the substrate, and the initial carbon film layer at least includes SP 2 hybridization bonds, including:
- the carbon-containing gas is subjected to plasma bombardment at a first preset temperature, a first preset power, a first preset frequency and a first preset pressure to form an initial carbon film layer attached to the surface of the substrate.
- the carbonaceous gas includes cyclopropane.
- the first preset temperature includes 300°C to 650°C
- the first preset power includes 1500W to 2500W
- the first preset frequency includes 10MHZ to 15MHZ
- the first preset pressure includes 3torr to 10torr.
- modified ions are injected into the initial carbon film layer to convert the SP 2 hybrid bonds into SP 3 hybrid bonds to obtain a target carbon film layer, including:
- modified gas ionizing the modified gas at a second preset temperature to form modified ions
- the high-energy ion beam is injected into the initial carbon film layer after passing through a high-speed electric field to form a target carbon film layer.
- the modified gas is carbon monoxide
- the modified ions are carbon ions
- the modified gas is diborane
- the modified ions are boron ions.
- the second preset temperature is normal temperature.
- the thickness of the initial carbon film layer includes 100 nm to 300 nm.
- the implantation depth of the modified ions of the initial carbon film layer is less than 2/3 of the thickness of the initial carbon film layer.
- the injection amount of the modified ions is 1 ⁇ 10 15 to 4 Ions/cm 2 ⁇ 10 15 Ions/cm 2 .
- a semiconductor structure comprising:
- Target carbon film layer the target carbon film layer includes SP 2 hybridization bonds and SP 3 hybridization bonds, and the target carbon film layer is formed by injecting modified ions into the initial carbon film layer formed on the substrate. It is obtained that the content of SP 2 hybrid bonds of the target carbon film layer is higher than the content of SP 2 hybrid bonds of the initial carbon film layer.
- the hardness of the target carbon film layer is greater than the hardness of the initial carbon film layer.
- the etching selectivity of the target carbon film layer is higher than the etching selectivity of the initial carbon film layer.
- the orbit of the SP 2 hybrid bond in the initial carbon film layer is an equilateral triangle structure similar to graphene, and the carbon atom forms a covalent bond with the three adjacent carbon atoms in the SP 2 hybrid orbit. Single bond.
- the orbit of the SP 3 hybrid bond is a diamond-like tetrahedron structure.
- Each carbon atom interacts with another SP 3 hybrid orbital.
- Four carbon atoms form a covalent bond, forming a regular tetrahedral structure. All the valence electrons of the C atoms participate in the formation of the covalent bond. At this time, there are no free electrons, so the SP 3 hybrid bond is harder.
- the hardness of the carbon film layer after the modified ions are injected is greater, the etching selectivity increases during the etching process, and the carbon film layer is not easily deformed, which can ensure the etching shape of the etching window and improve the product yield; at the same time, due to the increase in By reducing the hardness of the carbon film layer, the thickness of the carbon film layer can be appropriately reduced during the etching process, thereby saving carbon materials and reducing manufacturing costs.
- Figure 1 is a schematic diagram of an etching window in the related art
- Figure 2 is a flow chart of an etching method of a semiconductor structure in an embodiment of the present disclosure
- Figure 3 is a schematic diagram of the initial carbon film layer in an embodiment of the present disclosure.
- Figure 4 is a schematic diagram of a target carbon film layer in an embodiment of the present disclosure.
- Figure 5 is a schematic diagram of the XPS energy spectrum of the initial carbon film layer in the embodiment of the present disclosure
- Figure 6 is a schematic diagram of the XPS energy spectrum of the target carbon film layer in the embodiment of the present disclosure.
- Figure 7 is a schematic diagram of an etching window in an embodiment of the present disclosure.
- Example embodiments will now be described more fully with reference to the accompanying drawings.
- Example embodiments may, however, be embodied in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments.
- the same reference numerals in the drawings indicate the same or similar structures, and thus their detailed descriptions will be omitted.
- the drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale.
- an etching process is usually used for patterning to form the desired pattern.
- the carbon film layer 200 is one of the commonly used mask layers.
- the loss during the etching process is large.
- FIG. 2 shows a flow chart of the method of forming a semiconductor structure of the present disclosure.
- the forming method of the present disclosure includes step S110 - step S130, which:
- Step S110 provide a substrate
- Step S120 forming an initial carbon film layer on the surface of the substrate, where the initial carbon film layer at least includes SP 2 hybrid bonds;
- Step S130 Inject modified ions into the initial carbon film layer to convert the SP 2 hybrid bonds into SP 3 hybrid bonds to obtain a target carbon film layer.
- the orbital of the SP 2 hybrid bond in the initial carbon film layer is an equilateral triangle structure similar to graphene, and the carbon atom forms a covalent unit with the three adjacent carbon atoms in the SP 2 hybrid orbit. bond.
- the orbit of the SP3 hybrid bond is a diamond-like tetrahedral structure.
- Each carbon atom interacts with the other four in an SP 3 hybrid orbit. Carbon atoms form covalent bonds and form a regular tetrahedral structure. All the valence electrons of C atoms participate in the formation of covalent bonds. At this time, there are no free electrons, so the SP 3 hybrid bond is harder.
- the hardness of the carbon film layer after the modified ions are injected is greater, the etching selectivity increases during the etching process, and the carbon film layer is not easily deformed, which can ensure the etching shape of the etching window and improve the product yield; at the same time, due to the increase in By reducing the hardness of the carbon film layer, the thickness of the carbon film layer can be appropriately reduced during the etching process, thereby saving carbon materials and reducing manufacturing costs.
- step S110 a substrate is provided.
- the substrate 1 can have a flat plate structure, which can be rectangular, circular, elliptical, polygonal or irregularly shaped, and its material can be silicon or other semiconductor materials.
- the substrate 1 is not used here. The shape and material are subject to special restrictions.
- step S120 an initial carbon film layer is formed on the surface of the substrate 1 , and the initial carbon film layer at least includes SP 2 hybridization bonds.
- the initial carbon film layer 2 may be a thin film formed on the substrate 1 or a coating formed on the substrate 1 .
- the type of the initial carbon film layer 2 is not particularly limited here.
- chemical vapor deposition, physical vapor deposition, atomic layer deposition, vacuum evaporation or magnetron sputtering can be used to form the initial carbon film layer 2 on the surface of the substrate 1 .
- the material of the initial carbon film layer 2 may be carbon, which may include SP 2 hybridization bonds 300 .
- the initial carbon film layer 2 may also include SP 3 hybridization bonds 400 , where the hybridization in the initial carbon film layer 2
- the type of key is specially limited.
- the thickness of the initial carbon film layer 2 may be 100 nm to 300 nm. For example, it may be 100 nm, 150 nm, 200 nm, 250 nm or 300 nm. Of course, the thickness of the initial carbon film layer 2 may also be There are others, which will not be listed here.
- the carbon-containing gas can be subjected to plasma at a first preset temperature, a first preset power, a first preset frequency, and a first preset pressure using an inert gas.
- the bombardment generates a large amount of active plasma, which can be deposited on the surface of the substrate 1 to form an initial carbon film layer 2 attached to the surface of the substrate 1 .
- the first preset temperature may be a higher temperature.
- the first preset temperature may include 300°C to 650°C.
- it may be 300°C, 400°C, 500°C. ° C, 600 ° C or 650 ° C.
- the first preset temperature can also be other temperature values, which will not be listed here.
- the first preset power may be a higher power.
- the first preset power may include 1500W to 2500W.
- it may be 1500W, 1800W, 2100W, 2400W or 2500W.
- the first preset power can also be other power values, which are not listed here.
- the first preset frequency may be a higher frequency.
- the first preset frequency may include 10MHZ ⁇ 15MHZ.
- it may be 10MHZ, 11MHZ, 12MHZ, 13MHZ, or 13.56MHZ. , 14MHZ or 15MHZ.
- the first preset frequency can also be other frequency values, which will not be listed one by one here.
- the first preset pressure may include a higher pressure.
- the first preset pressure may include 3 torr to 10 torr.
- it may be 3 torr, 5 torr, 7 torr, 9 torr or 10 torr.
- the first preset pressure can also be other pressure values, which are not listed here.
- the carbon-containing gas may include cyclopropane (C 3 H 6 ), through which 2 carbon atoms may be provided for forming the initial carbon film layer .
- the carbon-containing gas can also be other gases, for example, it can also be ethylene (C 2 H 4 ), etc.
- the carbon-containing gas is not specifically limited here.
- chemical vapor deposition can be used, using cyclopropane (C 3 H 6 ) as a carbon-containing gas, under a high temperature condition of 550°C, a power of 2100W, and a high frequency of 13.56Mhz.
- Argon ions or helium ions are used to bombard carbon-containing gas under pressure conditions of and 8 torr, thereby generating a large amount of active carbon plasma.
- the carbon plasma can be deposited on the substrate 1 to form an initial carbon film layer 2.
- multiple different types of carbon film layers can be formed according to different formation conditions.
- the ratios of SP 3 hybrid bonds 400 and SP 2 hybrid bonds 300 in each carbon film layer are different and can be screened out.
- a carbon film layer with a higher ratio of SP 3 hybridization bonds 400 to SP 2 hybridization bonds 300, and this carbon film layer is used as the initial carbon film layer 2 in the present disclosure.
- the first carbon film layer can be defined as an APFe film layer, which can be formed using cyclopropane (C 3 H 6 ) as a carbon-containing gas at a temperature of 300°C and a power of 1250W using an atomic layer deposition process.
- APFe film layer it is detected that the proportion of SP 2 hybrid bond 300 in the APFe film layer is 83.81%, and the proportion of SP 3 hybrid bond 400 is 16.19%;
- the second carbon film layer can be defined as the APF550 film layer , cyclopropane (C 3 H 6 ) can be used as a carbon-containing gas, and an APF550 film layer is formed using an atomic layer deposition process at a temperature of 550°C and a power of 1600W.
- the SP 2 hybridization bond in the APF550 film layer is 300
- the proportion of is 75.63%, and the proportion of SP 3 hybrid bond 400 is 24.37%
- the third carbon film layer can be defined as the DLC film layer
- ethylene (C 2 H 4 ) can be a carbon-containing gas at a temperature of
- the DLC film layer was formed using an atomic layer deposition process at 275°C and a power of 400W/2400W.
- the fourth carbon film layer can be defined as the Kodiak film layer, which can be formed using atomic layer deposition process at a temperature of 630°C and a power of 2100W using cyclopropane (C 3 H 6 ) as a carbon-containing gas.
- Kodiak film layer it is detected that the proportion of SP 2 hybrid bonds 300 in the Kodiak film layer is 70.14%, and the proportion of SP 3 hybrid bonds 400 is 29.76%.
- the Kodiak film layer can be used as the initial carbon film layer 2 in this disclosure.
- step S130 modified ions are injected into the initial carbon film layer to convert the SP 2 hybrid bonds into SP 3 hybrid bonds to obtain a target carbon film layer.
- Modified ions can be implanted into the initial carbon film layer 2 through ion implantation to obtain the target carbon film layer 3 .
- the carbon-hydrogen bonds in the SP 2 hybrid bonds 300 in the initial carbon film layer 2 are broken, and the carbon ions and modified ions recombine to form SP 3 hybrid bonds 400.
- Each carbon atom in the SP 3 hybrid bond 400 forms a covalent bond with four other carbon atoms in the SP 3 hybrid orbit, forming a regular tetrahedral structure. All C atom valence electrons participate in the formation of covalent bonds. At this time, there are no free electrons.
- the SP 3 hybrid bond 400 has a greater hardness, thereby making the hardness of the finally formed target carbon film layer 3 greater than the hardness of the initial carbon film layer 2 . Therefore, the hardness of the target carbon film layer 3 after the modified ions are implanted is relatively large, and the etching selectivity ratio increases during the etching process (that is, the etching selectivity ratio of the target carbon film layer 3 is higher than that of the initial carbon film layer 2 Selectivity ratio), the target carbon film layer 3 is not easily deformed, which can ensure the etching shape of the etching window and improve the product yield; at the same time, due to the increased hardness of the target carbon film layer 3, the target can be appropriately reduced during the etching process.
- the thickness of the carbon film layer 3 can save carbon materials and reduce manufacturing costs.
- the implantation depth of the modified ions of the initial carbon film layer 2 is less than 2/3 of the thickness of the initial carbon film layer 2.
- damage to the underlying layer during the ion implantation process can be avoided.
- the substrate 1 can avoid defects in the substrate 1 caused by ion implantation, which can improve the product yield;
- the modified ions can interact with the structure of the upper part of the initial carbon film layer 2 reaction, thereby causing the finally obtained target carbon film layer 3 to have the characteristics of high hardness on the upper surface and low hardness on the lower surface, thereby making the subsequent etching process using the target carbon film layer 3 as a hard mask.
- the etching rate on the side far away from the substrate 1 is small, and the etching rate on the side close to the substrate 1 is large, so as to avoid the etching rate close to the substrate 1 during the plasma etching process of the target carbon film layer 3
- the etching rate slows down due to insufficient energy on one side.
- the ion implantation depth of the initial carbon film layer 2 can be 1/5, 1/4, 1/3 or 2/3 of the thickness of the initial carbon film layer 2. Of course, it can also be other depths, which will not be discussed here. List them one by one.
- the injection amount of modified ions is 1 ⁇ 10 15 Ions/cm 2 to 4 ⁇ 10 15 Ions/cm 2 .
- the injection amount may be 1 ⁇ 10 15 Ions/cm 2 cm 2 , 2 ⁇ 10 15 Ions/cm 2 , 3 ⁇ 10 15 Ions/cm 2 or 4 ⁇ 10 15 Ions/cm 2 .
- other injection amounts are also possible, which will not be listed here.
- modified ions are injected into the initial carbon film layer 2 to convert SP 2 hybridization bonds 300 into SP 3 hybridization bonds 400 to obtain the target carbon film layer 3 (i.e. Step S130) may include steps S210-step S230, wherein:
- Step S210 ionize the modified gas at a second preset temperature to form modified ions.
- the modified gas can be passed through the ion machine at the second preset temperature to ionize the modified gas to obtain modified ions.
- the second preset temperature may be normal temperature.
- the modified gas may be a carbon-containing gas, and the carbon-containing gas may obtain carbon ions after being ionized by an ion machine, that is, the modified ions may be carbon ions.
- the modified gas can be carbon monoxide (CO).
- CO carbon monoxide
- the modified gas can also be other carbon-containing gases, which are not listed here.
- the modified gas may be a boron-containing gas.
- the boron-containing gas may be ionized by an ion machine to obtain boron ions, that is, the modified ions may be boron ions.
- the modified gas can be diborane (B 2 H 6 ).
- the modified gas can also be other boron-containing gases, which are not listed here.
- modified ions can also be other ions, as long as the SP 2 hybrid bonds 300 in the initial carbon film layer 2 can be converted into SP 3 hybrid bonds 400, the type of modified ions will not be specified here. Special restrictions.
- Step S220 Accelerate the modified ions to form a high-energy ion beam.
- An electric field can be used to accelerate the modified ions to obtain a high-energy ion beam with higher energy.
- Step S230 the high-energy ion beam is injected into the initial carbon film layer 2 after passing through a high-speed electric field to form the target carbon film layer 3 .
- the high-energy ion beam can be further accelerated by a high-speed electric field to increase the injection energy of the high-energy ion beam.
- the initial carbon film layer 2 after the modified ions are injected can be defined as the target carbon film layer 3.
- the modified ions are carbon ions
- the carbon-hydrogen bonds in the initial carbon film layer 2 are broken, the carbon atoms are reorganized, and the original carbon-hydrogen bonds are reorganized to form
- the carbon-carbon bond increases the binding energy, which in turn helps to enhance the hardness of the carbon film layer. That is, the hardness of the target carbon film layer 3 is greater than the hardness of the initial carbon film layer 2.
- the carbon film layer can be targeted Layer 3 serves as a mask layer, which can improve the etching selectivity.
- the target carbon film layer 3 is not easily deformed, ensuring the etching shape of the etching window and improving product yield; at the same time, during the process of forming the mask layer, it can be appropriately The thickness of the target carbon film layer 3 is reduced, carbon materials are saved, and manufacturing costs are reduced.
- the modified ions are boron ions
- the carbon-hydrogen bonds in the initial carbon film layer 2 are broken, and the carbon atoms and boron ions are reorganized, and the original carbon-hydrogen bonds After reorganization, carbon-carbon bonds or carbon-boron bonds are formed, and the binding energy increases, which in turn helps to enhance the hardness of the carbon film layer.
- the thickness of the initial carbon film layer 2 and the implantation conditions of modified ions can be controlled so that the SP 3 hybridization bond 400 in the finally formed target carbon film layer 3 and the SP
- the ratio of 2 hybrid bonds 300 is greater than 2:3.
- the ratio of SP 3 hybrid bonds 400 to SP 2 hybrid bonds 300 in the target carbon film layer 3 can be 2:3, 2.1:3, 2.2:3, 2.3:3 or 2.4:3.
- the ratio of SP 3 hybrid bonds 400 to SP 2 hybrid bonds 300 in the target carbon film layer 3 can also be other values, which are not listed here.
- the ratio of SP 2 hybrid bonds 300 and SP 3 hybrid bonds 400 in the target carbon film layer 3 can be detected after modifying ions are implanted, so as to determine the target carbon Whether the hardness of film layer 3 is improved compared to the initial carbon film layer 2.
- the X-ray photoelectron spectrum (XPS) of the initial carbon film layer 2 and the target carbon film layer 3 can be collected separately, and the SP 2 in the target carbon film layer 3 can be determined based on the peaks in the X-ray photoelectron spectrum (XPS). Whether the ratio of the hybrid bonds 300 and the SP 3 hybrid bonds 400 has changed compared to the ratio of the SP 2 hybrid bonds 300 and the SP 3 hybrid bonds 400 in the initial carbon film layer 2 .
- Figure 5 shows the X-ray photoelectron spectrum (XPS) of the initial carbon film layer 2 in the embodiment of the present disclosure
- Figure 6 shows the X-ray photoelectron spectrum (XPS) of the target carbon film layer 3 in the embodiment of the present disclosure.
- the X-axis represents the binding energy
- the Y-axis represents the photoelectron intensity
- 284.7Ev is the characteristic peak of carbon SP 2 hybridization
- 285Ev binding energy represents the characteristic peak of carbon SP 3 hybridization
- curve a represents the carbon film measured by XPS The total peak value; according to Figure 5 and Figure 6, it can be concluded that the peak area of SP 3 hybridization in the target carbon film layer 3 becomes larger, indicating that the proportion of SP 3 in the carbon film layer formed after modified ion implantation becomes larger.
- the ratio of SP 3 hybrid bonds 400 to SP 2 hybrid bonds 300 in the initial carbon film layer 2 is 29.76:70.24; the ratio of SP 3 hybrid bonds 400 to SP 2 hybrid bonds in the target carbon film layer 3
- the ratio of 300 is 42.15:57.85.
- the ratio of SP 3 hybrid bonds 400 has increased by 41.6%.
- the methods can be used respectively.
- the target carbon film layer 3 and the initial carbon film layer 2 are used as mask layers to etch the film layer to be measured. By comparing the morphology of the etching window formed in the film layer to be measured after etching, the target carbon film layer 3 is determined. Whether the etching selectivity ratio can be improved.
- a film layer 5 to be measured can be formed on a substrate 4, a target carbon film layer 3 is formed on the surface of the film layer 5 to be measured, and at the same time, a film layer to be measured is formed on another substrate 4. 5.
- Carbon film layer 2 and target carbon film layer 3 are used as masks, and the same etching gas or etching solution is used to etch the film layer 5 to be measured to form an etching window 501; a transmission electron microscope (Transmission Electron Microscope, referred to as TEM) is used to collect respectively.
- TEM Transmission Electron Microscope
- the sidewall profile of the etching window 101 formed by using the initial carbon film layer 2 as a mask appears to be larger at the top and narrower at the bottom; the sidewall profile of the etching window 501 formed by using the target carbon film layer 3 as a mask is straighter and does not appear above.
- the phenomenon of a large surface and a narrow surface indicates that the target carbon film layer 3 is harder and has a higher etching selectivity.
- the etching rate of the target carbon film layer 3 is lower than the etching rate of the initial carbon film layer 2 , that is, the etching selectivity ratio of the target carbon film layer 3 is higher than the etching selectivity ratio of the initial carbon film layer 2 .
- the target carbon film layer is obtained when the thickness of the initial carbon film layer 2 is 160nm and the injection amount of modified ions is 3.00*E15 3 has the lowest etching rate and the highest hardness.
- the etching rate of the target carbon film layer 3 formed after modified ion implantation is 32.9, which is 25% lower than the initial carbon film layer 2 without modified ion implantation (its etching rate is 42.6).
- Embodiments of the present disclosure also provide a semiconductor structure.
- the semiconductor structure can be formed by the method for forming a semiconductor structure in any of the above embodiments.
- the semiconductor structure of the present disclosure can include a substrate 1 and a substrate formed on the substrate.
- the target carbon film layer 3 on the substrate 1 can be obtained by injecting modified ions into the initial carbon film layer 2 formed on the substrate 1.
- the SP 2 hybridization bond of the target carbon film layer 3 is The content may be higher than the content of SP 2 hybrid bonds of the initial carbon film layer 2 .
- the semiconductor structure of the present disclosure contains a large amount of SP 3 hybrid bonds 400.
- the orbits of the SP 3 hybrid bonds 400 are diamond-like tetrahedral structures. Each carbon atom interacts with four other carbon atoms in SP 3 hybrid orbits.
- a covalent bond is formed to form a regular tetrahedral structure. All the valence electrons of the C atom participate in the formation of the covalent bond. At this time, there are no free electrons, so the SP 3 hybrid bond 400 has a greater hardness.
- the semiconductor structure of the present disclosure has a relatively large hardness, and can be used as a mask layer in the etching process to increase the etching selectivity ratio, and the semiconductor structure is not easily deformed during the etching process, ensuring the etching shape of the etching window, and improving product quality. efficiency; at the same time, due to the high hardness of the semiconductor structure, the thickness of the semiconductor structure can be appropriately reduced during the etching process, which can save materials and reduce manufacturing costs.
- the substrate 1 can have a flat plate structure, which can be rectangular, circular, elliptical, polygonal or irregularly shaped, and its material can be silicon or other semiconductor materials.
- the substrate 1 is not used here. The shape and material are subject to special restrictions.
- the target carbon film layer 3 can be formed on the surface of the substrate 1.
- an initial carbon film layer 2 can be formed on the substrate 1, and modified ions can be injected into the initial carbon film layer 2 to form Target carbon film layer 3.
- the thickness of the initial carbon film layer 2 may be 100 nm to 300 nm. For example, it may be 100 nm, 150 nm, 200 nm, 250 nm or 300 nm. Of course, the thickness of the initial carbon film layer 2 may also be There are others, which will not be listed here.
- Modified ions can be implanted into the initial carbon film layer 2 through ion implantation to obtain the target carbon film layer 3 .
- the carbon-hydrogen bonds in the SP 2 hybrid bonds 300 in the initial carbon film layer 2 are broken, and the carbon ions and modified ions recombine to form SP 3 hybrid bonds 400.
- Each carbon atom in the SP 3 hybrid bond 400 forms a covalent bond with four other carbon atoms in the SP 3 hybrid orbit, forming a regular tetrahedral structure. All C atom valence electrons participate in the formation of covalent bonds. At this time, there are no free electrons.
- the SP 3 hybrid bond 400 has a greater hardness, thereby making the hardness of the finally formed target carbon film layer 3 greater than the hardness of the initial carbon film layer 2 . Therefore, the hardness of the target carbon film layer 3 after the modified ions are implanted is relatively large, and the etching selectivity ratio increases during the etching process (that is, the etching selectivity ratio of the target carbon film layer 3 is higher than that of the initial carbon film layer 2 Selectivity ratio), the target carbon film layer 3 is not easily deformed, which can ensure the etching shape of the etching window and improve the product yield; at the same time, due to the increased hardness of the target carbon film layer 3, the target can be appropriately reduced during the etching process.
- the thickness of the carbon film layer 3 can save carbon materials and reduce manufacturing costs.
- the modified ions may be carbon ions.
- the carbon-hydrogen bonds in the initial carbon film layer 2 are broken, and the carbon atoms are reorganized.
- the carbon-hydrogen bonds are reorganized to form carbon-carbon bonds, and the binding energy increases, which in turn helps to enhance the hardness of the carbon film layer. That is, the hardness of the target carbon film layer 3 is greater than the hardness of the initial carbon film layer 2.
- the target carbon film layer 3 can be used as a mask layer, which can improve the etching selectivity.
- the target carbon film layer 3 is not easily deformed, which can ensure the etching shape of the etching window and improve the product yield; at the same time, when forming During the mask layer process, the thickness of the target carbon film layer 3 can be appropriately reduced, saving carbon materials and reducing manufacturing costs.
- the modifying ions may be boron ions. After boron ions enter the initial carbon film layer 2 , the carbon-hydrogen bonds in the initial carbon film layer 2 are broken, and recombination occurs between carbon atoms and boron ions. , the original carbon-hydrogen bonds are reorganized to form carbon-carbon bonds or carbon-boron bonds, and the binding energy increases, which in turn helps to enhance the hardness of the carbon film layer.
- the thickness of the initial carbon film layer 2 and the implantation conditions of modified ions can be controlled so that the SP 3 hybridization bond 400 in the finally formed target carbon film layer 3 and the SP
- the ratio of 2 hybrid bonds 300 is greater than 2:3.
- the ratio of SP 3 hybrid bonds 400 to SP 2 hybrid bonds 300 in the target carbon film layer 3 can be 2:3, 2.1:3, 2.2:3, 2.3:3 or 2.4:3.
- the ratio of SP 3 hybrid bonds 400 to SP 2 hybrid bonds 300 in the target carbon film layer 3 can also be other values, which are not listed here.
- the ratio of SP 2 hybridization bonds 300 and SP 3 hybridization bonds 400 in the target carbon film layer 3 may be detected after modifying ions are injected, so as to determine the target carbon Whether the hardness of film layer 3 is improved compared to the initial carbon film layer 2.
- the X-ray photoelectron spectrum (XPS) of the initial carbon film layer 2 and the target carbon film layer 3 can be collected separately, and the SP 2 in the target carbon film layer 3 can be determined based on the peaks in the X-ray photoelectron spectrum (XPS). Whether the ratio of the hybrid bonds 300 and the SP 3 hybrid bonds 400 has changed compared to the ratio of the SP 2 hybrid bonds 300 and the SP 3 hybrid bonds 400 in the initial carbon film layer 2 .
- Figure 5 shows the X-ray photoelectron spectrum (XPS) of the initial carbon film layer 2 in the embodiment of the present disclosure
- Figure 6 shows the X-ray photoelectron spectrum (XPS) of the target carbon film layer 3 in the embodiment of the present disclosure.
- the X-axis represents the binding energy
- the Y-axis represents the photoelectron intensity
- 284.7Ev is the characteristic peak of carbon SP 2 hybridization
- 285Ev binding energy represents the characteristic peak of carbon SP 3 hybridization
- curve a represents the carbon film measured by XPS The total peak value; according to Figure 5 and Figure 6, it can be concluded that the peak area of SP 3 hybridization in the target carbon film layer 3 becomes larger, indicating that the proportion of SP 3 in the carbon film layer formed after modified ion implantation becomes larger.
- the ratio of SP 3 hybrid bonds 400 to SP 2 hybrid bonds 300 in the initial carbon film layer 2 is 29.76:70.24; the ratio of SP 3 hybrid bonds 400 to SP 2 hybrid bonds in the target carbon film layer 3
- the ratio of 300 is 42.15:57.85.
- the ratio of SP 3 hybrid bonds 400 has increased by 41.6%.
- the methods can be used respectively.
- the target carbon film layer 3 and the initial carbon film layer 2 are used as mask layers to etch the film layer to be measured. By comparing the morphology of the etching window formed in the film layer to be measured after etching, the target carbon film layer 3 is determined. Whether the etching selectivity ratio can be improved.
- a film layer 5 to be measured can be formed on a substrate 4, a target carbon film layer 3 is formed on the surface of the film layer 5 to be measured, and at the same time, a film layer to be measured is formed on another substrate 4. 5.
- Carbon film layer 2 and target carbon film layer 3 are used as masks, and the same etching gas or etching solution is used to etch the film layer 5 to be measured to form an etching window 501; a transmission electron microscope (Transmission Electron Microscope, referred to as TEM) is used to collect respectively.
- TEM Transmission Electron Microscope
- the sidewall profile of the etching window 101 formed by using the initial carbon film layer 2 as a mask appears to be larger at the top and narrower at the bottom; the sidewall profile of the etching window 501 formed by using the target carbon film layer 3 as a mask is straighter and does not appear above.
- the phenomenon of a large surface and a narrow surface indicates that the target carbon film layer 3 is harder and has a higher etching selectivity.
- the etching rate of the target carbon film layer 3 is lower than the etching rate of the initial carbon film layer 2 , that is, the etching selectivity ratio of the target carbon film layer 3 is higher than the etching selectivity ratio of the initial carbon film layer 2 .
- the target carbon film layer is obtained when the thickness of the initial carbon film layer 2 is 160nm and the injection amount of modified ions is 3.00*E15 3 has the lowest etching rate and the highest hardness.
- the etching rate of the target carbon film layer 3 formed after modified ion implantation is 32.9, which is 25% lower than the initial carbon film layer 2 without modified ion implantation (its etching rate is 42.6).
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Abstract
本公开是关于半导体技术领域,涉及一种半导体结构及其形成方法。本公开的形成方法包括:提供衬底;在所述衬底的表面形成初始碳膜层,所述初始碳膜层至少包括SP 2杂化键;向所述初始碳膜层内注入改性离子,以使所述SP 2杂化键转化为SP 3杂化键,以得到目标碳膜层。本公开的形成方法可增大碳膜层的硬度,在蚀刻过程中蚀刻选择比增大,碳膜层不易变形,可保证蚀刻窗口的蚀刻形状,提高产品良率;同时,由于增大了碳膜层的硬度,在蚀刻过程中,可适当的减小碳膜层的厚度,可节省碳材料,降低制造成本。 (图4)
Description
交叉引用
本公开要求于2022年7月20日提交的申请号为202210859721.2名称为“半导体结构及其形成方法”的中国专利申请的优先权,该中国专利申请的全部内容通过引用全部并入本文。
本公开涉及半导体技术领域,具体而言,涉及一种半导体结构及其形成方法。
图案化工艺是半导体器件制程过程中的重要工艺之一,目前,在图案化工艺过程中常采用碳膜层作为硬掩膜;然而,现有碳膜层的硬度较小,在蚀刻过程中,常因损耗较大而变形,进而导致蚀刻窗口变形,产品良率较低。
需要说明的是,在上述背景技术部分公开的信息仅用于加强对本公开的背景的理解,因此可以包括不构成对本领域普通技术人员已知的现有技术的信息。
发明内容
有鉴于此,本公开提供一种半导体结构及其形成方法,可增大碳膜层的硬度,提高产品良率。
根据本公开的一个方面,提供一种半导体结构的形成方法,包括:
提供衬底;
在所述衬底的表面形成初始碳膜层,所述初始碳膜层至少包括SP
2杂化键;
向所述初始碳膜层内注入改性离子,以使所述SP
2杂化键转化为SP
3杂化键,得到目标碳膜层。
在本公开的一种示例性实施例中,所述目标碳膜层的硬度大于所述 初始碳膜层的硬度。
在本公开的一种示例性实施例中,所述目标碳膜层的刻蚀选择比高于所述初始碳膜层的刻蚀选择比。
在本公开的一种示例性实施例中,在所述衬底表面形成初始碳膜层,所述初始碳膜层至少包括SP
2杂化键,包括:
在第一预设温度、第一预设功率、第一预设频率及第一预设压力下对含碳气体进行等离子体轰击,以形成附着于所述衬底的表面的初始碳膜层。
在本公开的一种示例性实施例中,所述含碳气体包括环丙烷。
在本公开的一种示例性实施例中,所述第一预设温度包括300℃~650℃,所述第一预设功率包括1500W~2500W,所述第一预设频率包括10MHZ~15MHZ,所述第一预设压力包括3torr~10torr。
在本公开的一种示例性实施例中,向所述初始碳膜层内注入改性离子,以使所述SP
2杂化键转化为SP
3杂化键,得到目标碳膜层,包括:
在第二预设温度下对改性气体进行离子化,以形成改性离子;
对所述改性离子进行加速,以形成高能离子束;
将所述高能离子束经过高速电场后注入至所述初始碳膜层内,以形成目标碳膜层。
在本公开的一种示例性实施例中,所述改性气体为一氧化碳,所述改性离子为碳离子。
在本公开的一种示例性实施例中,所述改性气体为乙硼烷,所述改性离子为硼离子。
在本公开的一种示例性实施例中,所述第二预设温度为常温。
在本公开的一种示例性实施例中,所述初始碳膜层的厚度包括100nm~300nm。
在本公开的一种示例性实施例中,所述初始碳膜层的所述改性离子的注入深度小于所述初始碳膜层的厚度的2/3。
在本公开的一种示例性实施例中,所述改性离子的注入量为1×10
15~4Ions/cm
2×10
15Ions/cm
2。
根据本公开的一个方面,提供一种半导体结构,所述半导体结构包 括:
衬底;
目标碳膜层,所述目标碳膜层包括SP
2杂化键和SP
3杂化键,所述目标碳膜层通过对形成于所述衬底上的初始碳膜层注入改性离子的方法获得,所述目标碳膜层的SP
2杂化键的含量高于所述初始碳膜层的SP
2杂化键的含量。
在本公开的一种示例性实施例中,所述目标碳膜层的硬度大于所述初始碳膜层的硬度。
在本公开的一种示例性实施例中,所述目标碳膜层的刻蚀选择比高于所述初始碳膜层的刻蚀选择比。
本公开的半导体结构及其形成方法,初始碳膜层中的SP
2杂化键的轨道是类似石墨烯的正三角形结构,碳原子以SP
2杂化轨道与邻近的三个碳原子形成共价单键,此时,碳原子结构中还存在一个未参与杂化的孤对电子,导致SP
2杂化键较为活泼,碳膜层硬度较小;当改性离子进入初始碳膜层后,孤对电子获得能量发生跃迁,使得相邻的碳原子之间形成SP
3杂化键,SP
3杂化键的轨道是类金刚石正四面体结构,每个碳原子都以SP
3杂化轨道与另外四个碳原子形成共价键,构成正四面体结构,所有的C原子价电子都参与共价键的形成,此时,没有自由电子,因而SP
3杂化键硬度较大。因此,注入改性离子后的碳膜层的硬度较大,在蚀刻过程中蚀刻选择比增大,碳膜层不易变形,可保证蚀刻窗口的蚀刻形状,提高产品良率;同时,由于增大了碳膜层的硬度,在蚀刻过程中,可适当的减小碳膜层的厚度,可节省碳材料,降低制造成本。
应当理解的是,以上的一般描述和后文的细节描述仅是示例性和解释性的,并不能限制本公开。
此处的附图被并入说明书中并构成本说明书的一部分,示出了符合本公开的实施例,并与说明书一起用于解释本公开的原理。显而易见地,下面描述中的附图仅仅是本公开的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图获得其他 的附图。
图1为相关技术中蚀刻窗口的示意图;
图2为本公开实施方式中半导体结构的蚀刻方法的流程图;
图3为本公开实施方式中初始碳膜层的示意图;
图4为本公开实施方式中目标碳膜层的示意图;
图5为本公开实施方式中初始碳膜层的XPS能谱示意图;
图6为本公开实施方式中目标碳膜层的XPS能谱示意图;
图7为本公开实施方式中蚀刻窗口的示意图。
附图标记说明:
100、待蚀刻膜层;101、蚀刻窗口;200、碳膜层;1、衬底;2、初始碳膜层;3、目标碳膜层;4、基底;5、待测膜层;501、蚀刻窗口;300、SP
2杂化键;400、SP
3杂化键。
现在将参考附图更全面地描述示例实施方式。然而,示例实施方式能够以多种形式实施,且不应被理解为限于在此阐述的实施方式;相反,提供这些实施方式使得本公开将全面和完整,并将示例实施方式的构思全面地传达给本领域的技术人员。图中相同的附图标记表示相同或类似的结构,因而将省略它们的详细描述。此外,附图仅为本公开的示意性图解,并非一定是按比例绘制。
虽然本说明书中使用相对性的用语,例如“上”“下”来描述图标的一个组件对于另一组件的相对关系,但是这些术语用于本说明书中仅出于方便,例如根据附图中所述的示例的方向。能理解的是,如果将图标的装置翻转使其上下颠倒,则所叙述在“上”的组件将会成为在“下”的组件。当某结构在其它结构“上”时,有可能是指某结构一体形成于其它结构上,或指某结构“直接”设置在其它结构上,或指某结构通过另一结构“间接”设置在其它结构上。
用语“一个”、“一”、“该”、“所述”和“至少一个”用以表示存在一个或多个要素/组成部分/等;用语“包括”和“具有”用以表示开放式的包括在内的意思并且是指除了列出的要素/组成部分/等之外还可存在另外的 要素/组成部分/等;用语“第一”和“第二”等仅作为标记使用,不是对其对象的数量限制。
在半导体器件的制程过程中,通常采用蚀刻工艺进行图案化,进而形成所需图案。在图案化过程中,需要在待蚀刻膜层100的表面形成掩膜层,对掩膜层进行光刻形成掩膜图案,随后通过蚀刻的方式将掩膜图案转移至待蚀刻膜层100中。碳膜层200是常用的掩膜层之一,目前,在以碳膜层200作为掩膜层进行蚀刻的过程中,由于碳膜层200的硬度较小,在蚀刻过程中损耗较大,因此,需要涂覆一层厚度较大的碳膜层200,制造成本较高;且在蚀刻过程中碳膜层200的蚀刻选择比较小,掩膜图案边缘的掩膜材料损耗较大,致使掩膜图案变形,进而导致最终在待蚀刻膜层100中形成的蚀刻窗口101变形(如图1所示),产品良率较低。
基于此,本公开实施方式提供了一种半导体结构的形成方法,图2示出了本公开的半导体结构的形成方法的流程图,参见图2所示,本公开的形成方法包括步骤S110-步骤S130,其中:
步骤S110,提供衬底;
步骤S120,在所述衬底的表面形成初始碳膜层,所述初始碳膜层至少包括SP
2杂化键;
步骤S130,向所述初始碳膜层内注入改性离子,以使所述SP
2杂化键转化为SP
3杂化键,得到目标碳膜层。
本公开的半导体结构的形成方法,初始碳膜层中的SP
2杂化键的轨道是类似石墨烯的正三角形结构,碳原子以SP
2杂化轨道与邻近的三个碳原子形成共价单键,此时,碳原子结构中还存在一个未参与杂化的孤对电子,导致SP
2杂化键较为活泼,碳膜层硬度较小;当改性离子进入初始碳膜层后,孤对电子获得能量发生跃迁,使得相邻的碳原子之间形成SP
3杂化键,SP3杂化键的轨道是类金刚石正四面体结构,每个碳原子都以SP
3杂化轨道与另外四个碳原子形成共价键,构成正四面体结构,所有的C原子价电子都参与共价键的形成,此时,没有自由电子,因而SP
3杂化键硬度较大。因此,注入改性离子后的碳膜层的硬度较大,在蚀刻过程中蚀刻选择比增大,碳膜层不易变形,可保证蚀刻窗口的蚀刻形状,提高 产品良率;同时,由于增大了碳膜层的硬度,在蚀刻过程中,可适当的减小碳膜层的厚度,可节省碳材料,降低制造成本。
下面对本公开的半导体结构的形成方法的各步骤及其技术细节进行详细说明:
如图2所示,在步骤S110中,提供衬底。
如图3及图4所示,衬底1可呈平板结构,其可为矩形、圆形、椭圆形、多边形或不规则图形,其材料可以是硅或其他半导体材料,在此不对衬底1的形状及材料做特殊限定。
如图2所示,在步骤S120中,在所述衬底1的表面形成初始碳膜层,所述初始碳膜层至少包括SP
2杂化键。
如图3所示,初始碳膜层2可以是形成于衬底1上的薄膜,也可以是形成于衬底1上的涂层,在此不对初始碳膜层2的类型做特殊限定。举例而言,可采用化学气相沉积、物理气相沉积、原子层沉积、真空蒸镀或磁控溅射等方式在衬底1表面形成初始碳膜层2。初始碳膜层2的材料可为碳,其内部可包括SP
2杂化键300,当然,初始碳膜层2还可包括SP
3杂化键400,在此初始碳膜层2中的杂化键的类型做特殊限定。
在本公开的一些实施方式中,初始碳膜层2的厚度可为100nm~300nm,举例而言,其可为100nm、150nm、200nm、250nm或300nm,当然,初始碳膜层2的厚度还可以是其他,在此不再一一列举。
在本公开的一种示例性实施方式中,可在第一预设温度、第一预设功率、第一预设频率及第一预设压力下,并利用惰性气体对含碳气体进行等离子体轰击,产生大量的活跃的等离子体,等离子体可沉积在衬底1表面,进而形成附着于衬底1的表面的初始碳膜层2。
在本公开的一些实施方式中,第一预设温度可为较高的温度,举例而言,第一预设温度可包括300℃~650℃,例如,其可为300℃、400℃、500℃、600℃或650℃,当然,第一预设温度还可以是其他温度值,在此不再一一列举。
在本公开的一些实施方式中,第一预设功率可为较高功率,举例而言,第一预设功率可包括1500W~2500W,例如,其可为1500W、1800W、2100W、2400W或2500W,当然,第一预设功率还可以是其他功率值, 在此不再一一列举。
在本公开的一些实施方式中,第一预设频率可为较高频率,举例而言,第一预设频率可包括10MHZ~15MHZ,例如,其可为10MHZ、11MHZ、12MHZ、13MHZ、13.56MHZ、14MHZ或15MHZ,当然,第一预设频率还可以是其他频率值,在此不再一一列举。
在本公开的一些实施方式中,第一预设压力可包括较高压力,举例而言,第一预设压力可包括3torr~10torr,例如,其可为3torr、5torr、7torr、9torr或10torr,当然,第一预设压力还可以是其他压力值,在此不再一一列举。
在本公开的一种示例性实施方式中,含碳气体可包括环丙烷(C
3H
6),可通过环丙烷(C
3H
6)提供用于形成初始碳膜层2碳原子。当然,含碳气体,还可以是其他气体,例如,其还可以乙烯(C
2H
4)等,在此不对含碳气体做特殊限定。
在本公开的一种示例性实施方式中,可采用化学气相沉积的方式,以环丙烷(C
3H
6)为含碳气体,在550℃的高温条件、2100W的功率、13.56Mhz的高频率和8torr的压力条件下利用氩离子或氦离子轰击含碳气体,进而产生大量活跃的碳等离子体,碳等离子体可沉积在衬底1上,进而形成初始碳膜层2。
在本公开的一些实施方式中,可根据不同的形成条件形成多种不同类型的碳膜层,各碳膜层中SP
3杂化键400与SP
2杂化键300的比例不同,可筛选出SP
3杂化键400与SP
2杂化键300的比例较高的碳膜层,并将该碳膜层作为本公开中的初始碳膜层2。
举例而言,可将第一种碳膜层定义为APFe膜层,可以环丙烷(C
3H
6)为含碳气体,在温度为300℃,功率为1250W的条件下采用原子层沉积工艺形成APFe膜层,经检测APFe膜层中的SP
2杂化键300的占比为83.81%,SP
3杂化键400的占比为16.19%;可将第二种碳膜层定义为APF550膜层,可以环丙烷(C
3H
6)为含碳气体,在温度为550℃,功率为1600W的条件下采用原子层沉积工艺形成APF550膜层,经检测APF550膜层中的SP
2杂化键300的占比为75.63%,SP
3杂化键400的占比为24.37%;可将第三种碳膜层定义为DLC膜层,可以乙烯(C
2H
4) 为含碳气体,在温度为275℃,功率为400W/2400W的条件下采用原子层沉积工艺形成DLC膜层,经检测DLC膜层中的SP
2杂化键300的占比为71.16%,SP
3杂化键400的占比为28.84%;可将第四种碳膜层定义为Kodiak膜层,可以环丙烷(C
3H
6)为含碳气体,在温度为630℃,功率为2100W的条件下采用原子层沉积工艺形成Kodiak膜层,经检测Kodiak膜层中的SP
2杂化键300的占比为70.14%,SP
3杂化键400的占比为29.76%。可将Kodiak膜层作为本公开中的初始碳膜层2。
如图2所示,在步骤S130中,向所述初始碳膜层内注入改性离子,以使所述SP
2杂化键转化为SP
3杂化键,得到目标碳膜层。
可通过离子注入的方式向初始碳膜层2中注入改性离子,进而得到目标碳膜层3。改性离子进入初始碳膜层2后,初始碳膜层2中的SP
2杂化键300中的碳氢键发生断裂,碳离子与改性离子发生重组,进而形成SP
3杂化键400,SP
3杂化键400中的每个碳原子都以SP
3杂化轨道与另外四个碳原子形成共价键,构成正四面体结构,所有的C原子价电子都参与共价键的形成,此时,没有自由电子,因而,相比于SP
2杂化键300,SP
3杂化键400硬度较大,进而使得最终形成的目标碳膜层3的硬度大于初始碳膜层2的硬度。因此,注入改性离子后的目标碳膜层3的硬度较大,在蚀刻过程中蚀刻选择比增大(即,目标碳膜层3的刻蚀选择比高于初始碳膜层2的刻蚀选择比),目标碳膜层3不易变形,可保证蚀刻窗口的蚀刻形状,提高产品良率;同时,由于增大了目标碳膜层3的硬度,在蚀刻过程中,可适当的减小目标碳膜层3的厚度,可节省碳材料,降低制造成本。
在本公开的一种示例性实施方式中,初始碳膜层2的改性离子的注入深度小于初始碳膜层2的厚度的2/3,一方面,可以避免在离子注入过程中损伤其下层的衬底1,避免因离子注入而引发衬底1缺陷,可提高产品良率;另一方面,通过控制改性离子的注入深度,可以使改性离子与初始碳膜层2上部的结构发生反应,进而使得最终得到的目标碳膜层3形成上面硬度大,下面硬度小的特性,进而使得后续以目标碳膜层3作为硬掩膜进行蚀刻的过程中,对目标碳膜层3而言,其远离衬底1的一侧的蚀刻速率较小,其靠近衬底1的一侧的蚀刻速率较大,避免在对目 标碳膜层3进行等离子蚀刻的过程中,其靠近衬底1的一侧因能量不足而使得蚀刻速率减慢。
举例而言,初始碳膜层2的离子注入深度可为初始碳膜层2厚度的1/5、1/4、1/3或2/3,当然,也可以是其他深度,在此不再一一列举。
在本公开的一种示例性实施方式中,改性离子的注入量为1×10
15Ions/cm
2~4×10
15Ions/cm
2,例如,其注入量可为1×10
15Ions/cm
2、2×10
15Ions/cm
2、3×10
15Ions/cm
2或4×10
15Ions/cm
2,当然,也可以是其他注入量,在此不再一一列举。
在本公开的一种示例性实施方式中,向初始碳膜层2内注入改性离子,以使SP
2杂化键300转化为SP
3杂化键400,以得到目标碳膜层3(即步骤S130)可包括步骤S210-步骤S230,其中:
步骤S210,在第二预设温度下对改性气体进行离子化,以形成改性离子。
可在第二预设温度下使改性气体经过离子机,进而将改性气体离子化,以获得改性离子。在本公开实施方式中,第二预设温度可以是常温。
在本公开的一些实施方式中,改性气体可以为含碳气体,含碳气体经过离子机离子化后可获得碳离子,即:改性离子可为碳离子。举例而言,改性气体可为一氧化碳(CO),当然,改性气体还可以是其他的含碳气体,在此不再一一列举。
在本公开的另一些实施方式中,改性气体可以为含硼气体,含硼气体经过离子机离子化后可获得硼离子,即:改性离子可为硼离子。举例而言,改性气体可为乙硼烷(B
2H
6),当然,改性气体还可以是其他的含硼气体,在此不再一一列举。
需要说明的是,改性离子也可以是其他离子,只要能将初始碳膜层2中的SP
2杂化键300转化为SP
3杂化键400即可,在此不对改性离子的类型做特殊限定。
步骤S220,对所述改性离子进行加速,以形成高能离子束。
可采用电场对改性离子进行加速,进而获得较高能量的高能离子束。
步骤S230,将所述高能离子束经过高速电场后注入至所述初始碳膜层2内,以形成目标碳膜层3。
如图4所示,可通过高速电场对高能离子束进行进一步加速,以提高高能离子束的注入能量,可将注入改性离子后的初始碳膜层2定义为目标碳膜层3。
当改性离子为碳离子时,碳离子进入初始碳膜层2后,初始碳膜层2中的碳-氢键发生断裂,碳原子之间发生重组,原有的碳-氢键重组后形成碳-碳键,结合能增大,进而有助于增强碳膜层的硬度,即,目标碳膜层3的硬度大于初始碳膜层2的硬度,在图案化工艺过程中,可以目标碳膜层3作为掩膜层,可提高蚀刻选择比,在蚀刻过程中目标碳膜层3不易变形,可保证蚀刻窗口的蚀刻形状,提高产品良率;同时,在形成掩膜层的过程中可适当的减小目标碳膜层3的厚度,节省碳材料,降低制造成本。
当改性离子为硼离子时,硼离子进入初始碳膜层2后,初始碳膜层2中的碳-氢键发生断裂,碳原子和硼离子之间发生重组,原有的碳-氢键重组后形成碳-碳键或碳-硼键,结合能增大,进而有助于增强碳膜层的硬度。
在本公开的一种示例性实施方式中,可通过控制初始碳膜层2的厚度以及改性离子的注入条件,进而使得最终形成的目标碳膜层3中的SP
3杂化键400与SP
2杂化键300的比例大于2:3。举例而言,目标碳膜层3中的SP
3杂化键400与SP
2杂化键300的比例可为2:3、2.1:3、2.2:3、2.3:3或2.4:3,当然,目标碳膜层3中的SP
3杂化键400与SP
2杂化键300的比例也可为其他数值,在此不在一一列举。
在本公开的一种示例性实施方式中,在注入改性离子后可对目标碳膜层3中的SP
2杂化键300和SP
3杂化键400的比例进行检测,以便于确定目标碳膜层3相较于初始碳膜层2其硬度是否得以提高。
举例而言,可分别采集初始碳膜层2和目标碳膜层3的X射线光电子能谱(XPS),根据X射线光电子能谱(XPS)中的峰值判断目标碳膜层3中的SP
2杂化键300和SP
3杂化键400的比例相较于初始碳膜层2中的SP
2杂化键300和SP
3杂化键400的比例是否发生变化。图5示出了本公开实施方式中的初始碳膜层2的X射线光电子能谱(XPS),图6示出了本公开实施方式中的目标碳膜层3的X射线光电子能谱(XPS), 图中,X轴代表结合能;Y轴表示光电子强度;284.7Ev是碳SP
2杂化的特征峰;285Ev结合能代表碳SP
3杂化的特征峰;曲线a表示XPS测出来碳膜的总峰值;根据图5和图6可以得出,目标碳膜层3中SP
3杂化的峰面积变大,说明改性离子注入后形成的碳膜层中的SP
3比例变大。
经计算,可知初始碳膜层2中的SP
3杂化键400与SP
2杂化键300的比例为29.76:70.24;目标碳膜层3中的SP
3杂化键400与SP
2杂化键300的比例为42.15:57.85,相较于初始碳膜层2,SP
3杂化键400的比例提升了41.6%。
为了进一步验证经改性离子注入后形成的目标碳膜层3的硬度是否得以增大,进而确定经改性离子注入后形成的目标碳膜层3的蚀刻选择比是否得以增大,可分别采用目标碳膜层3及初始碳膜层2作为掩膜层,对待测膜层进行蚀刻,通过对蚀刻后在待测膜层中形成的蚀刻窗口的形貌进行对比,进而确定目标碳膜层3的蚀刻选择比是否得以提高。
举例而言,如图7所示,可在一基底4上形成待测膜层5,在待测膜层5表面形成目标碳膜层3,同时,在另一基底4上形成待测膜层5,在待测膜层5的表面形成初始碳膜层2;采用同样的工艺分别在初始碳膜层2和目标碳膜层3内形成相同的掩膜图案;分别以具有掩膜图案的初始碳膜层2和目标碳膜层3为掩膜,采用同样的蚀刻气体或蚀刻溶液对待测膜层5进行蚀刻以形成蚀刻窗口501;采用透射电子显微镜(Transmission Electron Microscope,简称TEM)分别采集以具有掩膜图案的初始碳膜层2和以具有掩膜图案的目标碳膜层3为掩膜所形成的蚀刻窗口501的微观形貌,进而通过微观形貌判断目标碳膜层3的蚀刻选择比是否大于初始碳膜层2的时刻选择比。
采用初始碳膜层2为掩膜形成的蚀刻窗口101的侧壁轮廓出现上面大下面窄的现象;采用目标碳膜层3为掩膜形成的蚀刻窗口501的侧壁轮廓更直,没有出现上面大下面窄的现象,说明目标碳膜层3的硬度更大,蚀刻选择比更高。
在本公开的一种示例性实施方式中,由于目标碳膜层3相较于初始碳膜层2其硬度有所增大,进而使得在以目标碳膜层3为掩膜进行蚀刻的过程中目标碳膜层3的蚀刻率低于初始碳膜层2的蚀刻率,即目标碳 膜层3的蚀刻选择比高于初始碳膜层2的蚀刻选择比。
在本公开的一种示例性实施方式中,经过大量实验验证,最终得出在初始碳膜层2的厚度为160nm,改性离子的注入量为3.00*E15的情况下获得的目标碳膜层3的蚀刻率最低,硬度最大。经改性离子注入后形成的目标碳膜层3的蚀刻速率为32.9,相较于未经改性离子注入的初始碳膜层2(其蚀刻速率为42.6),其蚀刻率降低了25%。
需要说明的是,尽管在附图中以特定顺序描述了本公开中半导体结构的形成方法的各个步骤,但是,这并非要求或者暗示必须按照该特定顺序来执行这些步骤,或是必须执行全部所示的步骤才能实现期望的结果。附加的或备选的,可以省略某些步骤,将多个步骤合并为一个步骤执行,以及/或者将一个步骤分解为多个步骤执行等。
本公开实施方式还提供一种半导体结构,该半导体结构可由上述任一实施方式中的半导体结构的形成方法形成,如图4所示,本公开的半导体结构可包括衬底1及形成于衬底1上的目标碳膜层3,该目标碳膜层3可通过对形成于衬底1上的初始碳膜层2注入改性离子的方法获得,目标碳膜层3的SP
2杂化键的含量可高于初始碳膜层2的SP
2杂化键的含量。
本公开的半导体结构中的SP
3杂化键400含量较多,SP
3杂化键400的轨道是类金刚石正四面体结构,每个碳原子都以SP
3杂化轨道与另外四个碳原子形成共价键,构成正四面体结构,所有的C原子价电子都参与共价键的形成,此时,没有自由电子,因而SP
3杂化键400硬度较大。因此,本公开的半导体结构的硬度较大,以其作为蚀刻工艺中的掩膜层可增大蚀刻选择比,且在蚀刻过程中半导体结构不易变形,可保证蚀刻窗口的蚀刻形状,提高产品良率;同时,由于半导体结构的硬度较大,在蚀刻过程中,可适当的减小半导体结构的厚度,可节省材料,降低制造成本。
如图3及图4所示,衬底1可呈平板结构,其可为矩形、圆形、椭圆形、多边形或不规则图形,其材料可以是硅或其他半导体材料,在此不对衬底1的形状及材料做特殊限定。
如图4所示,目标碳膜层3可形成于衬底1的表面,举例而言,可在衬底1上形成初始碳膜层2,对初始碳膜层2注入改性离子,进而形 成目标碳膜层3。
在本公开的一些实施方式中,初始碳膜层2的厚度可为100nm~300nm,举例而言,其可为100nm、150nm、200nm、250nm或300nm,当然,初始碳膜层2的厚度还可以是其他,在此不再一一列举。
可通过离子注入的方式向初始碳膜层2中注入改性离子,进而得到目标碳膜层3。改性离子进入初始碳膜层2后,初始碳膜层2中的SP
2杂化键300中的碳氢键发生断裂,碳离子与改性离子发生重组,进而形成SP
3杂化键400,SP
3杂化键400中的每个碳原子都以SP
3杂化轨道与另外四个碳原子形成共价键,构成正四面体结构,所有的C原子价电子都参与共价键的形成,此时,没有自由电子,因而,相比于SP
2杂化键300,SP
3杂化键400硬度较大,进而使得最终形成的目标碳膜层3的硬度大于初始碳膜层2的硬度。因此,注入改性离子后的目标碳膜层3的硬度较大,在蚀刻过程中蚀刻选择比增大(即,目标碳膜层3的刻蚀选择比高于初始碳膜层2的刻蚀选择比),目标碳膜层3不易变形,可保证蚀刻窗口的蚀刻形状,提高产品良率;同时,由于增大了目标碳膜层3的硬度,在蚀刻过程中,可适当的减小目标碳膜层3的厚度,可节省碳材料,降低制造成本。
在本公开的一些实施方式中,改性离子可为碳离子,碳离子进入初始碳膜层2后,初始碳膜层2中的碳-氢键发生断裂,碳原子之间发生重组,原有的碳-氢键重组后形成碳-碳键,结合能增大,进而有助于增强碳膜层的硬度,即,目标碳膜层3的硬度大于初始碳膜层2的硬度,在图案化工艺过程中,可以目标碳膜层3作为掩膜层,可提高蚀刻选择比,在蚀刻过程中目标碳膜层3不易变形,可保证蚀刻窗口的蚀刻形状,提高产品良率;同时,在形成掩膜层的过程中可适当的减小目标碳膜层3的厚度,节省碳材料,降低制造成本。
在本公开的一些实施方式中,改性离子可为硼离子,硼离子进入初始碳膜层2后,初始碳膜层2中的碳-氢键发生断裂,碳原子和硼离子之间发生重组,原有的碳-氢键重组后形成碳-碳键或碳-硼键,结合能增大,进而有助于增强碳膜层的硬度。
在本公开的一种示例性实施方式中,可通过控制初始碳膜层2的厚 度以及改性离子的注入条件,进而使得最终形成的目标碳膜层3中的SP
3杂化键400与SP
2杂化键300的比例大于2:3。举例而言,目标碳膜层3中的SP
3杂化键400与SP
2杂化键300的比例可为2:3、2.1:3、2.2:3、2.3:3或2.4:3,当然,目标碳膜层3中的SP
3杂化键400与SP
2杂化键300的比例也可为其他数值,在此不在一一列举。
在本公开的一种示例性实施方式中,在注入改性离子后可对目标碳膜层3中的SP
2杂化键300和SP
3杂化键400的比例进行检测,以便于确定目标碳膜层3相较于初始碳膜层2其硬度是否得以提高。
举例而言,可分别采集初始碳膜层2和目标碳膜层3的X射线光电子能谱(XPS),根据X射线光电子能谱(XPS)中的峰值判断目标碳膜层3中的SP
2杂化键300和SP
3杂化键400的比例相较于初始碳膜层2中的SP
2杂化键300和SP
3杂化键400的比例是否发生变化。图5示出了本公开实施方式中的初始碳膜层2的X射线光电子能谱(XPS),图6示出了本公开实施方式中的目标碳膜层3的X射线光电子能谱(XPS),图中,X轴代表结合能;Y轴表示光电子强度;284.7Ev是碳SP
2杂化的特征峰;285Ev结合能代表碳SP
3杂化的特征峰;曲线a表示XPS测出来碳膜的总峰值;根据图5和图6可以得出,目标碳膜层3中SP
3杂化的峰面积变大,说明改性离子注入后形成的碳膜层中的SP
3比例变大。
经计算,可知初始碳膜层2中的SP
3杂化键400与SP
2杂化键300的比例为29.76:70.24;目标碳膜层3中的SP
3杂化键400与SP
2杂化键300的比例为42.15:57.85,相较于初始碳膜层2,SP
3杂化键400的比例提升了41.6%。
为了进一步验证经改性离子注入后形成的目标碳膜层3的硬度是否得以增大,进而确定经改性离子注入后形成的目标碳膜层3的蚀刻选择比是否得以增大,可分别采用目标碳膜层3及初始碳膜层2作为掩膜层,对待测膜层进行蚀刻,通过对蚀刻后在待测膜层中形成的蚀刻窗口的形貌进行对比,进而确定目标碳膜层3的蚀刻选择比是否得以提高。
举例而言,如图7所示,可在一基底4上形成待测膜层5,在待测膜层5表面形成目标碳膜层3,同时,在另一基底4上形成待测膜层5,在待测膜层5的表面形成初始碳膜层2;采用同样的工艺分别在初始碳 膜层2和目标碳膜层3内形成相同的掩膜图案;分别以具有掩膜图案的初始碳膜层2和目标碳膜层3为掩膜,采用同样的蚀刻气体或蚀刻溶液对待测膜层5进行蚀刻以形成蚀刻窗口501;采用透射电子显微镜(Transmission Electron Microscope,简称TEM)分别采集以具有掩膜图案的初始碳膜层2和以具有掩膜图案的目标碳膜层3为掩膜所形成的蚀刻窗口501的微观形貌,进而通过微观形貌判断目标碳膜层3的蚀刻选择比是否大于初始碳膜层2的时刻选择比。
采用初始碳膜层2为掩膜形成的蚀刻窗口101的侧壁轮廓出现上面大下面窄的现象;采用目标碳膜层3为掩膜形成的蚀刻窗口501的侧壁轮廓更直,没有出现上面大下面窄的现象,说明目标碳膜层3的硬度更大,蚀刻选择比更高。
在本公开的一种示例性实施方式中,由于目标碳膜层3相较于初始碳膜层2其硬度有所增大,进而使得在以目标碳膜层3为掩膜进行蚀刻的过程中目标碳膜层3的蚀刻率低于初始碳膜层2的蚀刻率,即目标碳膜层3的蚀刻选择比高于初始碳膜层2的蚀刻选择比。
在本公开的一种示例性实施方式中,经过大量实验验证,最终得出在初始碳膜层2的厚度为160nm,改性离子的注入量为3.00*E15的情况下获得的目标碳膜层3的蚀刻率最低,硬度最大。经改性离子注入后形成的目标碳膜层3的蚀刻速率为32.9,相较于未经改性离子注入的初始碳膜层2(其蚀刻速率为42.6),其蚀刻率降低了25%。
本领域技术人员在考虑说明书及实践这里公开的发明后,将容易想到本公开的其它实施方案。本申请旨在涵盖本公开的任何变型、用途或者适应性变化,这些变型、用途或者适应性变化遵循本公开的一般性原理并包括本公开未公开的本技术领域中的公知常识或惯用技术手段。说明书和实施例仅被视为示例性的,本公开的真正范围和精神由所附的权利要求指出。
Claims (16)
- 一种半导体结构的形成方法,其中,包括:提供衬底;在所述衬底的表面形成初始碳膜层,所述初始碳膜层至少包括SP 2杂化键;向所述初始碳膜层内注入改性离子,以使所述SP 2杂化键转化为SP 3杂化键,得到目标碳膜层。
- 根据权利要求1所述的形成方法,其中,所述目标碳膜层的硬度大于所述初始碳膜层的硬度。
- 根据权利要求1所述的形成方法,其中,所述目标碳膜层的刻蚀选择比高于所述初始碳膜层的刻蚀选择比。
- 根据权利要求1所述的形成方法,其中,在所述衬底表面形成初始碳膜层,所述初始碳膜层至少包括SP 2杂化键,包括:在第一预设温度、第一预设功率、第一预设频率及第一预设压力下对含碳气体进行等离子体轰击,以形成附着于所述衬底的表面的初始碳膜层。
- 根据权利要求4所述的形成方法,其中,所述含碳气体包括环丙烷。
- 根据权利要求4所述的形成方法,其中,所述第一预设温度包括300℃~650℃,所述第一预设功率包括1500W~2500W,所述第一预设频率包括10MHZ~15MHZ,所述第一预设压力包括3torr~10torr。
- 根据权利要求1-6任一项所述的形成方法,其中,向所述初始碳膜层内注入改性离子,以使所述SP 2杂化键转化为SP 3杂化键,得到目标碳膜层,包括:在第二预设温度下对改性气体进行离子化,以形成改性离子;对所述改性离子进行加速,以形成高能离子束;将所述高能离子束经过高速电场后注入至所述初始碳膜层内,以形成目标碳膜层。
- 根据权利要求7所述的形成方法,其中,所述改性气体为一氧化碳,所述改性离子为碳离子。
- 根据权利要求7所述的形成方法,其中,所述改性气体为乙硼烷,所述改性离子为硼离子。
- 根据权利要求7所述的形成方法,其中,所述第二预设温度为常温。
- 根据权利要求7所述的形成方法,其中,所述初始碳膜层的厚度包括100nm~300nm。
- 根据权利要求7所述的形成方法,其中,所述初始碳膜层的所述改性离子的注入深度小于所述初始碳膜层的厚度的2/3。
- 根据权利要求7所述的形成方法,其中,所述改性离子的注入量为1×10 15Ions/cm 2~4×10 15Ions/cm 2。
- 一种半导体结构,其中,所述半导体结构包括:衬底;目标碳膜层,所述目标碳膜层包括SP 2杂化键和SP 3杂化键,所述目标碳膜层通过对形成于所述衬底上的初始碳膜层注入改性离子的方法获得,所述目标碳膜层的SP 2杂化键的含量高于所述初始碳膜层的SP 2杂化键的含量。
- 根据权利要求14所述的半导体结构,其中,所述目标碳膜层的硬度大于所述初始碳膜层的硬度。
- 根据权利要求14所述的半导体结构,其中,所述目标碳膜层的刻蚀选择比高于所述初始碳膜层的刻蚀选择比。
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