CN112103176B - Method for covalent grafting dielectric film on semiconductor surface - Google Patents
Method for covalent grafting dielectric film on semiconductor surface Download PDFInfo
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- CN112103176B CN112103176B CN202010953444.2A CN202010953444A CN112103176B CN 112103176 B CN112103176 B CN 112103176B CN 202010953444 A CN202010953444 A CN 202010953444A CN 112103176 B CN112103176 B CN 112103176B
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 98
- 238000000034 method Methods 0.000 title claims abstract description 45
- 239000012954 diazonium Substances 0.000 claims abstract description 39
- 239000000178 monomer Substances 0.000 claims abstract description 30
- 238000002161 passivation Methods 0.000 claims abstract description 26
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 claims abstract description 16
- 229920002554 vinyl polymer Polymers 0.000 claims abstract description 16
- 150000002500 ions Chemical class 0.000 claims abstract description 10
- -1 aryl diazonium salt Chemical class 0.000 claims description 32
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 29
- 239000000126 substance Substances 0.000 claims description 25
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 claims description 22
- 239000008367 deionised water Substances 0.000 claims description 19
- 229910021641 deionized water Inorganic materials 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- 239000000758 substrate Substances 0.000 claims description 16
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 12
- 238000006243 chemical reaction Methods 0.000 claims description 12
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-O diazynium Chemical compound [NH+]#N IJGRMHOSHXDMSA-UHFFFAOYSA-O 0.000 claims description 10
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 10
- 239000002253 acid Substances 0.000 claims description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 8
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 8
- 239000012445 acidic reagent Substances 0.000 claims description 8
- 239000003945 anionic surfactant Substances 0.000 claims description 8
- 238000004140 cleaning Methods 0.000 claims description 8
- 238000003756 stirring Methods 0.000 claims description 8
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 6
- 239000003153 chemical reaction reagent Substances 0.000 claims description 6
- 238000005530 etching Methods 0.000 claims description 6
- 229910052731 fluorine Inorganic materials 0.000 claims description 6
- 239000011737 fluorine Substances 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 5
- 229910052697 platinum Inorganic materials 0.000 claims description 5
- 238000004506 ultrasonic cleaning Methods 0.000 claims description 5
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 4
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 4
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 claims description 4
- 229910017604 nitric acid Inorganic materials 0.000 claims description 4
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 claims description 4
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 claims description 4
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 claims description 3
- 235000013024 sodium fluoride Nutrition 0.000 claims description 2
- 239000011775 sodium fluoride Substances 0.000 claims description 2
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 2
- 125000004203 4-hydroxyphenyl group Chemical group [H]OC1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims 1
- 150000001989 diazonium salts Chemical class 0.000 abstract description 11
- 238000005516 engineering process Methods 0.000 abstract description 10
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 238000009776 industrial production Methods 0.000 abstract description 3
- 239000011261 inert gas Substances 0.000 abstract description 3
- 229920000620 organic polymer Polymers 0.000 abstract description 3
- 239000010408 film Substances 0.000 description 35
- QPJSUIGXIBEQAC-UHFFFAOYSA-N n-(2,4-dichloro-5-propan-2-yloxyphenyl)acetamide Chemical compound CC(C)OC1=CC(NC(C)=O)=C(Cl)C=C1Cl QPJSUIGXIBEQAC-UHFFFAOYSA-N 0.000 description 17
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 229910052710 silicon Inorganic materials 0.000 description 8
- 239000010703 silicon Substances 0.000 description 8
- NKSJNEHGWDZZQF-UHFFFAOYSA-N ethenyl(trimethoxy)silane Chemical compound CO[Si](OC)(OC)C=C NKSJNEHGWDZZQF-UHFFFAOYSA-N 0.000 description 7
- 125000000636 p-nitrophenyl group Chemical group [H]C1=C([H])C(=C([H])C([H])=C1*)[N+]([O-])=O 0.000 description 7
- 239000004809 Teflon Substances 0.000 description 6
- 229920006362 Teflon® Polymers 0.000 description 6
- 229910018557 Si O Inorganic materials 0.000 description 3
- 239000002156 adsorbate Substances 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000017525 heat dissipation Effects 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000000026 X-ray photoelectron spectrum Methods 0.000 description 2
- 238000002083 X-ray spectrum Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- DAJSVUQLFFJUSX-UHFFFAOYSA-M sodium;dodecane-1-sulfonate Chemical group [Na+].CCCCCCCCCCCCS([O-])(=O)=O DAJSVUQLFFJUSX-UHFFFAOYSA-M 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- RILZRCJGXSFXNE-UHFFFAOYSA-N 2-[4-(trifluoromethoxy)phenyl]ethanol Chemical compound OCCC1=CC=C(OC(F)(F)F)C=C1 RILZRCJGXSFXNE-UHFFFAOYSA-N 0.000 description 1
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 238000007259 addition reaction Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005518 electrochemistry Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- FWDBOZPQNFPOLF-UHFFFAOYSA-N ethenyl(triethoxy)silane Chemical compound CCO[Si](OCC)(OCC)C=C FWDBOZPQNFPOLF-UHFFFAOYSA-N 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 231100001240 inorganic pollutant Toxicity 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
- H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
- H01L21/02118—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer carbon based polymeric organic or inorganic material, e.g. polyimides, poly cyclobutene or PVC
-
- 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
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
- H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
- H01L21/02282—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process liquid deposition, e.g. spin-coating, sol-gel techniques, spray coating
Abstract
The invention discloses a method for covalently grafting a dielectric film on the surface of a semiconductor; comprising the following steps: chemically grafting a passivation layer on the surface of a semiconductor by utilizing a diazonium salt technology in an atmospheric environment, wherein the passivation layer comprises diazonium salt organic polymer, and has controllable thickness, and the purpose of preventing the surface passivated by H from being oxidized and simultaneously being used as an intermediate layer for grafting a dielectric film is achieved; and electrically grafting a dielectric film layer on the surface by utilizing diazonium salt technology in the atmospheric environment. The method can be completely carried out in the atmospheric environment, does not need inert gas atmosphere protection, and can graft any soluble vinyl monomer, and particularly can prevent F ions from corroding the monomer and damaging certain covalent bonds. The method has wide applicability and low cost, and is suitable for the field of semiconductor manufacturing and industrial production.
Description
Technical Field
The invention belongs to the technical field of materials, relates to a method for covalently grafting a dielectric film on the surface of a semiconductor, and particularly relates to a method for covalently grafting a dielectric film with a monomer capable of being corroded by F ions on the surface of the semiconductor.
Background
With the rapid development of information society, the electronic industry demands of higher density, higher integration, and lower power consumption have presented new challenges to the semiconductor manufacturing industry. In 1965, the Intel (Intel) founder gordonMole proposes the well-known Mole's law: the number of components that can be accommodated on an integrated circuit doubles about every 18-24 months, and performance doubles. Moore's law has evolved over half a century, and in the latter moore's law era, issues of upper limit of moore's law, limit of chip size, heat dissipation problem, material limit, physical limit, etc. are faced. In order to continue moore's law, three-dimensional stacked through silicon via (Trough Silicon Via, TSV) packaging forms of chips have become a focus of attention, providing a new concept for semiconductor manufacturing. In three-dimensional TSV vertical interconnection, the preparation of an insulating layer is one of the key technologies, and the preparation of an insulating layer with high strength, high heat dissipation and low dielectric constant performance is an interfacial great challenge.
In the three-dimensional TSV insulating technology, the existing insulating layer mainly includes an inorganic insulating layer such as silicon dioxide, silicon nitride, silicate, etc., and an organic insulating layer. Compared with the inorganic insulating layer, the organic insulating layer has low dielectric constant and good deformability, and can be used as a stress buffer layer for relieving stress concentration, so that the organic insulating layer has great application prospect in the semiconductor manufacturing industry and is widely focused by scholars at home and abroad. In order to meet the manufacturing requirements of organic insulating layers, a method of preparing an organic thin film on a semiconductor surface has been gradually developed. The present group of patents CN201610510595, CN201910087448 proposed a method for preparing an organic thin film by covalent grafting on a semiconductor surface using a one-step process. The advantages of HF are utilized to prepare a compact and uniform organic film on the surface of the semiconductor substrate in one step in the atmospheric environment, and the preparation method has the advantages of simple steps, low cost and suitability for industrial production. However, HF is highly corrosive, and when certain special monomers are used for preparing insulating layers with high strength, high heat dissipation and low dielectric constant properties, HF may be corrosive to these monomers (e.g., monomers containing si—o bonds), which is also a limitation of HF. Therefore, how to use the advantages of the covalent grafting method in the molecular covalent grafting process and avoid the defects caused by the strong corrosiveness of the covalent grafting method is a great difficulty to be solved.
Disclosure of Invention
The subject group has proposed a diazonium salt-based one-step method of covalently grafting an organic polymer film onto an aqueous silicon surface. Where HF as a highly corrosive acid may be corrosive to many monomers, breaking covalent bonds such as si—o bonds. In view of the above problems, the present invention provides a method for covalently grafting a dielectric film on a semiconductor surface for the first time.
The invention is realized by the following technical scheme:
the invention relates to a method for covalently grafting a dielectric film on the surface of a semiconductor, which comprises the following steps:
s1, after a semiconductor substrate is cleaned, etching the surface of the semiconductor by adopting an HF solution to enable the semiconductor to form an H-passivated surface;
s2, carrying out surface passivation on the corroded semiconductor by adopting passivation solution containing aryl diazonium salt, so that the surface passivated by the semiconductor H is converted into the surface of a semiconductor-passivation layer;
s3, taking the semiconductor as a cathode, taking a platinum sheet as an anode, providing voltage by a pulse power supply, immersing the passivated semiconductor surface into a chemical solution containing vinyl monomers for electrochemical grafting reaction, and obtaining the dielectric film with the covalent grafting of the semiconductor surface.
In step S1, the reason for the cleaning is: the surface of a commercially purchased silicon wafer can absorb some organic or inorganic pollutants, and the pollutants are removed as much as possible by utilizing a physical cleaning process before grafting, so that the pollution to subsequent solutions is prevented, and redundant variables are introduced. Moreover, only HF solution can be selected for etching in this step, and other fluorine-containing reagents, such as fluoroboric acid or ammonium fluoride, cannot remove the natural oxide layer on the surface and form an H-passivated semiconductor surface.
As an embodiment of the present invention, in step S3, the vinyl monomer is a soluble vinyl monomer; the vinyl monomer can be corroded by F ions.
As an embodiment of the present invention, in step S1, the semiconductor substrate cleaning specifically includes: and sequentially carrying out ultrasonic cleaning on the semiconductor substrate by adopting acetone, alcohol and deionized water at the temperature of 10-40 ℃ for 5-30 min each time.
In step S1, the etching temperature is 10 to 40 ℃ and the etching time is 1 to 10 minutes; the fluorine-containing reagent is HF solution with the volume fraction of 0.5-5%.
As an embodiment of the present invention, in step S2, the passivation solution is: every 25-100 ml deionized water, adding 0.05-0.2 g anionic surfactant, 0.5-2 ml acid reagent, 0.25-1 ml fluorine-containing reagent and 0.075-0.3 g aryl diazonium salt, stirring for 5-10 min. Because experiments are carried out in the atmosphere, if the passivation step is not adopted, the surface is directly grafted by electrochemistry after being corroded, and because Si-H bonds are quickly oxidized to form Si-O bonds, a film with controllable thickness and compactness and uniformity can not be obtained.
Further examples are: the passivation solution is as follows: every 25-100 ml deionized water is added with 0.05-0.2 g Sodium Dodecyl Sulfate (SDS), 0.5-2 ml tetrafluoroboric acid (HBF) 4 ) 0.25-1 ml hydrofluoric acid (HF)0.075-0.3 g of diazonium p-nitrophenyl tetrafluoroborate (NBD) is stirred for 5-10 min.
As an embodiment of the present invention, the aryl diazonium salt is selected from the group consisting of 4-styryl phenyl tetrafluoroborate diazonium salt, 4-nitrobenzene tetrafluoroborate diazonium salt, and 4-hydroxy phenyl tetrafluoroborate diazonium salt.
Further, the anionic surfactant is selected from sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate or sodium dodecyl sulfate. The acidic reagent is selected from hydrochloric acid, sulfuric acid, tetrafluoroboric acid, nitric acid or phosphoric acid. The fluorine-containing reagent is selected from sodium fluoride, ammonium fluoride or hydrofluoric acid.
As one embodiment of the invention, the surface passivation temperature is 10-40 ℃ and the time is 10 s-20 min.
As one embodiment of the invention, the temperature of the electrochemical grafting reaction is 10-40 ℃ and the time is 1-100 min.
As one embodiment of the present invention, in the step S3, the maximum negative voltage of the output waveform of the pulse power source is-5 to-10V, and the duration t is on 20ms; the minimum negative pressure of the output waveform is-0.5 to-3V, and the duration time is 90ms.
As an embodiment of the present invention, in step S3, the chemical solution is: adding 17.5-70 ml tetrahydrofuran into every 7.5-30 ml deionized water, then adding 0.05-0.2 g soluble vinyl monomer, 0.05-0.2 g anionic surfactant, 0.75-3 ml acid reagent and 0.075-0.3 g aryl diazonium salt in turn, stirring for 5-10 min.
Further examples are: the chemical solution is as follows: every 25-100 ml deionized water, adding 0.5-2 ml vinyl trimethoxy silane, 0.05-0.2 g Sodium Dodecyl Sulfate (SDS), 0.75-3 ml concentrated sulfuric acid, 0.075-0.3 g diazonium p-nitrophenyl tetrafluoroborate (NBD) in turn, stirring for 5-10 min.
As an embodiment of the present invention, the soluble vinyl monomer is a vinyl monomer that is capable of being corroded by F ions. Such as vinyltrimethoxysilane, vinyltriethoxysilane, octavinylposs, and the like. In theory, the invention can graft all monomers that can be grafted by one-step chemical grafting methods (such as CN 201910087448) and can graft monomers that cannot be grafted by one-step chemical grafting methods (especially monomers that can be corroded by F ions).
Further, the anionic surfactant is selected from sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate or sodium dodecyl sulfate. The acidic reagent is selected from hydrochloric acid, sulfuric acid, tetrafluoroboric acid, nitric acid or phosphoric acid. The aryl diazonium salt is selected from 4-styryl phenyl tetrafluoroborate diazonium salt, 4-nitrobenzene tetrafluoroborate diazonium salt or 4-hydroxy phenyl tetrafluoroborate diazonium salt.
Compared with the prior art, the invention has the following beneficial effects:
1) The invention can be completely carried out in the atmospheric environment without inert gas atmosphere, greatly saves the cost and is suitable for industrial production;
2) The method adopts a two-step method based on diazonium salt technology for surface passivation to covalently graft the film on the surface of the semiconductor, so that on one hand, the problem that the Si surface is easily oxidized and is difficult to graft can be prevented, and on the other hand, the strong corrosion of F ions to monomers and certain covalent bonds in the grafting process can be prevented;
3) The invention can graft vinyl monomer which can be corroded by F ion, and the grafted film has controllable thickness and controllable components.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:
FIG. 1 is a schematic diagram of a pulse power waveform applied by a semiconductor surface grafted dielectric film of the present invention;
FIG. 2 is a full spectrum of X-ray spectra of a film obtained by grafting vinyl trimethoxy silane monomer onto a semiconductor surface grafted dielectric film according to the present invention by grafting via passivation and electrochemical grafting;
FIG. 3 is a full spectrum of an X-ray spectrum of a film obtained by grafting vinyl trimethoxy silane monomer onto a semiconductor surface by a one-step chemical grafting method.
Detailed Description
The present invention will be described in detail with reference to examples. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that several modifications and improvements can be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.
Example 1
The embodiment relates to a method for covalently grafting a dielectric film on the surface of a semiconductor based on diazonium salt technology, wherein the semiconductor substrate can be silicon, germanium or gallium arsenide (silicon is selected as the substrate in the embodiment), and the specific implementation steps are as follows:
step (1): sequentially carrying out ultrasonic cleaning on the semiconductor substrate by adopting acetone, alcohol and deionized water at the temperature of 20 ℃, wherein the cleaning time is 5min each time;
step (2): placing the washed semiconductor substrate in a 3v% HF solution at 20 ℃ for 1min;
step (3): directly immersing the corroded semiconductor surface into the prepared chemical solution (1) at the temperature of 20 ℃ for surface passivation for 30s, so that the semiconductor surface is converted into a passivation layer surface, and the semiconductor surface is prevented from being oxidized in the next reaction;
wherein the chemical solution (1) is prepared as follows: 50ml of deionized water was added to a Teflon beaker, followed by 0.1g of Sodium Dodecyl Sulfate (SDS), 2ml of tetrafluoroboric acid (HBF) were added to the deionized water in sequence, respectively 4 ) 1ml of hydrofluoric acid (HF), 0.1g of diazonium p-nitrophenyl tetrafluoroborate (NBD), and magnetically stirring for 5min to fully dissolve the diazonium p-nitrophenyl tetrafluoroborate;
immersing the surface of the passivated semiconductor into a prepared chemical solution (2) at the temperature of 20 ℃ for electrochemical grafting, wherein the semiconductor is connected with the negative electrode of a power supply as a cathode, the platinum sheet is connected with the positive electrode of the power supply as an anode, the voltage applied by the reaction is provided by a pulse power supply,the pulse waveform is shown in FIG. 1, in which V on For maximum negative pressure of output waveform of-10V, duration t on 20ms, V off The minimum negative pressure of the output waveform is-0.5V, the duration time is 90ms, the electrochemical grafting time is 5min, and the grafted semiconductor surface is washed by acetonitrile to remove physical adsorbate, so that the dielectric film with covalent grafting on the semiconductor surface is obtained;
wherein the chemical solution (2) is prepared by the following steps: 50ml of deionized water is added into a Teflon beaker, then 2ml of vinyltrimethoxysilane, 0.1g of Sodium Dodecyl Sulfate (SDS), 1ml of concentrated sulfuric acid and 0.1g of diazonium p-nitrophenyl tetrafluoroborate (NBD) are sequentially added into a solvent respectively, and the mixture is magnetically stirred for 5min to be fully dissolved;
and (5) measuring the thickness of the obtained dielectric film with the covalently grafted semiconductor surface by using an ellipsometer, wherein the obtained thickness is about 55nm. The bonding and content conditions of elements on the surface of the film are measured by an X-ray spectrometer, wherein Si-O bonds in vinyl trimethoxy silane exist in a spectrogram and have certain strength, and the atomic percentages of elements C, N, O, si are respectively as follows: 84.10%, 4.16%, 6.59%, 5.15% and XPS spectrum is shown in FIG. 2.
Example 2
The embodiment relates to a method for covalently grafting a dielectric film on the surface of a semiconductor based on diazonium salt technology, wherein the semiconductor substrate is silicon, and the specific implementation steps are as follows:
step (1): sequentially carrying out ultrasonic cleaning on the semiconductor substrate by adopting acetone, alcohol and deionized water at the temperature of 20 ℃, wherein the cleaning time is 5min each time;
placing the cleaned semiconductor substrate in 0.5v% HF solution at 20 ℃ for 10min;
directly immersing the corroded semiconductor surface into the prepared chemical solution (1) at the temperature of 20 ℃ for surface passivation for 30 seconds, so that the semiconductor surface is converted into a passivation layer surface, and the semiconductor surface is prevented from being oxidized in the next reaction;
wherein the chemical solution (1) is prepared as follows: 25ml of deionized water was added to a Teflon beaker, followed by 0.05g of Sodium Dodecyl Sulfate (SDS), 0.5ml of tetrafluoroboric acid (HBF) 4 ) 0.25ml hydrofluoric acid (HF), 0.075g p-nitrophenyl tetrafluoroborate diazonium salt (NBD), and magnetically stirring for 5min to fully dissolve;
immersing the surface of the passivated semiconductor into a prepared chemical solution (2) at the temperature of 20 ℃ for electrochemical grafting, wherein the semiconductor is connected with the negative electrode of a power supply as a cathode, the platinum sheet is connected with the positive electrode of the power supply as an anode, and the voltage applied by the reaction is provided by a pulse power supply, wherein V on For maximum negative pressure of output waveform of-5V, duration t on 20ms, V off The minimum negative pressure for outputting the waveform is-3V, the duration time is 90ms, the electrochemical grafting time is 10min, and the grafted semiconductor surface is washed by acetonitrile to remove physical adsorbate, so that the dielectric film with covalent grafting on the semiconductor surface is obtained;
wherein the chemical solution (2) is prepared by the following steps: 25ml of deionized water was added to a Teflon beaker, then 1ml of Methyl Methacrylate (MMA), 0.05g of Sodium Dodecyl Sulfate (SDS), 0.075ml of concentrated sulfuric acid, 0.075g of diazonium p-nitrophenyl tetrafluoroborate (NBD) were sequentially added to the solvent, and magnetically stirred for 5min to be fully dissolved;
and (5) measuring the thickness of the obtained dielectric film with the covalently grafted semiconductor surface by using an ellipsometer to obtain the dielectric film with the covalently grafted semiconductor surface, wherein the thickness is about 60nm.
Example 3
The embodiment relates to a method for covalently grafting a dielectric film on the surface of a semiconductor based on diazonium salt technology, wherein the semiconductor substrate is silicon, and the specific implementation steps are as follows:
step (1): sequentially carrying out ultrasonic cleaning on the semiconductor substrate by adopting acetone, alcohol and deionized water at the temperature of 20 ℃, wherein the cleaning time is 5min each time;
placing the cleaned semiconductor matrix in an HF solution with the volume fraction of 5% at the temperature of 20 ℃ for 1min;
directly immersing the corroded semiconductor surface into the prepared chemical solution (1) at the temperature of 20 ℃ for surface passivation for 1min to convert the semiconductor surface into a passivation layer surface, so that the semiconductor surface is prevented from being oxidized in the next reaction;
wherein the chemical solution (1) is prepared as follows: 100ml of deionized water was added to a Teflon beaker, followed by 0.2g of Sodium Dodecyl Sulfate (SDS), 1ml of tetrafluoroboric acid (HBF) were added to the deionized water in sequence, respectively 4 ) 0.5ml hydrofluoric acid (HF), 0.3g p-nitrobenzene tetrafluoroborate diazonium salt (NBD), and magnetically stirring for 5min to fully dissolve;
immersing the surface of the passivated semiconductor into a prepared chemical solution (2) at the temperature of 20 ℃ for electrochemical grafting, wherein the semiconductor is connected with the negative electrode of a power supply as a cathode, the platinum sheet is connected with the positive electrode of the power supply as an anode, and the voltage applied by the reaction is provided by a pulse power supply, wherein V on For maximum negative pressure of output waveform of-7V, duration t on 20ms, V off The minimum negative pressure for outputting the waveform is-1V, the duration time is 90ms, the electrochemical grafting time is 30min, and the grafted semiconductor surface is washed by acetonitrile to remove physical adsorbate, so that the dielectric film with covalent grafting on the semiconductor surface is obtained;
wherein the chemical solution (2) is prepared by the following steps: 100ml of deionized water is added into a Teflon beaker, then 4ml of Acrylic Acid (AA), 0.2g of Sodium Dodecyl Sulfate (SDS), 3ml of concentrated sulfuric acid and 0.3g of diazonium p-nitrophenyl tetrafluoroborate (NBD) are sequentially added into a solvent respectively, and the solution is magnetically stirred for 5min to be fully dissolved;
and (5) measuring the thickness of the obtained dielectric film with the covalently grafted semiconductor surface by using an ellipsometer to obtain the dielectric film with the covalently grafted semiconductor surface, wherein the thickness is about 200nm.
Comparative example 1
This comparative example relates to a method for covalently grafting a dielectric film onto a semiconductor surface, which is the same as in example 1, and which uses vinyltrimethoxysilane, except that: the HF-added one-step chemical grafting method of the prior patent CN201910087448 was employed. The element bonding and content conditions of the obtained dielectric film with the covalently grafted semiconductor surface are measured by XPS, wherein the Si content is extremely low, the Si content is reduced due to corrosion fracture of Si-O bonds after HF addition reaction, and the obtained C, N, O, si content atomic percentages are respectively as follows: 77.51%, 6.67%, 14.99%, 0.83%, and XPS spectrum is shown in FIG. 3. Thus, the method of the prior patent CN201910087448 has certain limitation, and the method of the invention has wider applicability and can graft the monomer which cannot be grafted by the one-step chemical grafting method.
Comparative example 2
This comparative example relates to a method for covalently grafting a dielectric film onto a semiconductor surface, the specific procedure being the same as in example 1, except that: and (3) no passivation step is carried out, and the semiconductor surface subjected to HF corrosion is directly immersed into a chemical solution (2) for electrochemical grafting reaction. In the comparative example, since the passivation step is not performed and the experiment is performed in an atmospheric environment, the passivated surface of the semiconductor H is easily oxidized, so that molecules in the electrochemical grafting solution cannot be grafted to the oxidized semiconductor surface, and thus, the semiconductor surface has no obvious organic film growth.
Comparative example 3
This comparative example relates to a method for covalently grafting a dielectric film onto a semiconductor surface, the specific procedure being the same as in example 1, except that: chemical grafting was used instead of electrochemical grafting (chemical solution was also the same as in example 1). This comparative example cannot perform an effective grafting reaction, and no organic thin film is generated on the semiconductor surface.
In summary, the method of the present invention includes: 1. chemically grafting a surface passivation layer on the surface of the semiconductor by utilizing diazonium salt technology in the atmospheric environment, wherein the passivation layer comprises diazonium salt organic polymer, has controllable thickness of 1-30 nm, and aims to prevent the surface of the semiconductor from being oxidized and serve as an intermediate layer for grafting a dielectric film on the surface of the semiconductor; 2. and the diazonium salt technology is utilized to electrically graft an organic film layer on the surface of the semiconductor in the atmospheric environment, and the thickness of the film layer is controllable and is 100 nm-2 mu m. The method can be completely carried out in the atmospheric environment, does not need inert gas atmosphere protection, can graft any soluble vinyl monomer, especially vinyl monomer which can be corroded by F ions, and can prevent F ions from corroding the monomer and damaging certain covalent bonds.
The foregoing describes specific embodiments of the present invention. It is to be understood that the invention is not limited to the particular embodiments described above, and that various changes and modifications may be made by one skilled in the art within the scope of the claims without affecting the spirit of the invention.
Claims (7)
1. A method of covalently grafting a dielectric film to a semiconductor surface, the method comprising the steps of:
s1, after a semiconductor substrate is cleaned, etching the surface of the semiconductor by adopting an HF solution to enable the semiconductor to form an H-passivated surface;
s2, carrying out surface passivation on the corroded semiconductor by adopting passivation solution containing aryl diazonium salt, so that the surface passivated by the semiconductor H is converted into the surface of a semiconductor-passivation layer; the passivation solution is as follows: adding 0.05-0.2 g of anionic surfactant, 0.5-2 ml of acid reagent, 0.25-1 ml of fluorine-containing reagent and 0.075-0.3 g of aryl diazonium salt into every 25-100 ml of deionized water, and stirring for 5-10 min to prepare the product;
s3, taking a semiconductor as a cathode, taking a platinum sheet as an anode, providing voltage by a pulse power supply, immersing the passivated semiconductor surface into a chemical solution containing vinyl monomers for electrochemical grafting reaction, and obtaining a dielectric film with the covalent grafting of the semiconductor surface; the chemical solution is as follows: adding 17.5-70 ml of tetrahydrofuran into each 7.5-30 ml of deionized water, sequentially adding 0.05-0.2 g of vinyl monomer, 0.05-0.2 g of anionic surfactant, 0.75-3 ml of acid reagent and 0.075-0.3 g of aryl diazonium salt, and stirring for 5-10 min to prepare the product;
the vinyl monomer is a soluble vinyl monomer; the vinyl monomer can be corroded by F ions.
2. The method of covalently grafting a dielectric film onto a semiconductor surface according to claim 1, wherein in step S1, the semiconductor substrate cleaning is specifically: and sequentially carrying out ultrasonic cleaning on the semiconductor substrate by adopting acetone, alcohol and deionized water at the temperature of 10-40 ℃, wherein the cleaning time is 5-30 min each time.
3. The method of covalent grafting a dielectric film onto a semiconductor surface according to claim 1, wherein in step S1, the etching temperature is 10-40 ℃ for 1 min-10 min; the HF solution is 0.5% -5% by volume.
4. The method of covalently grafting a dielectric film onto a semiconductor surface of claim 1, wherein the aryl diazonium salt in the passivating solution is selected from the group consisting of 4-styryl phenyl diazonium tetrafluoroborate, 4-nitrobenzene diazonium tetrafluoroborate, and 4-hydroxy phenyl diazonium tetrafluoroborate, the anionic surfactant is selected from the group consisting of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and sodium dodecyl sulfate, the acidic reagent is selected from the group consisting of hydrochloric acid, sulfuric acid, tetrafluoroboric acid, nitric acid, and phosphoric acid, and the fluorine-containing reagent is selected from the group consisting of sodium fluoride, ammonium fluoride, and hydrofluoric acid.
5. The method for covalently grafting a dielectric film on a semiconductor surface according to claim 1, wherein the surface passivation temperature is 10-40 ℃ for 10 s-20 min; the temperature of the electrochemical grafting reaction is 10-40 ℃ and the time is 1-100 min.
6. The method for covalently grafting a dielectric film on a semiconductor surface according to claim 1, wherein in the step S3, the maximum negative pressure of the output waveform of the pulse power source is-5 to-10V for a duration t on 20ms; the minimum negative pressure of the output waveform is-0.5 to-3V, and the duration time is 90ms.
7. The method of covalently grafting a dielectric film onto a semiconductor surface of claim 1, wherein the anionic surfactant is selected from the group consisting of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and sodium dodecyl sulfate, the acidic reagent is selected from the group consisting of hydrochloric acid, sulfuric acid, tetrafluoroboric acid, nitric acid, and phosphoric acid, and the aryl diazonium salt is selected from the group consisting of diazonium 4-styryl phenyl tetrafluoroborate, diazonium 4-nitrobenzene tetrafluoroborate, and diazonium 4-hydroxy phenyl tetrafluoroborate.
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| CN106206252A (en) * | 2016-06-30 | 2016-12-07 | 上海交通大学 | Method at surface of semiconductor substrates one-step method chemical graft organic membrane |
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| CN109880027A (en) * | 2019-01-29 | 2019-06-14 | 上海交通大学 | A kind of method that semiconductor surface prepares crosslinking copolymerization organic polymer |
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| CN106206252A (en) * | 2016-06-30 | 2016-12-07 | 上海交通大学 | Method at surface of semiconductor substrates one-step method chemical graft organic membrane |
| CN109860042A (en) * | 2019-01-29 | 2019-06-07 | 上海交通大学 | A kind of method that semiconductor surface prepares self-crosslinking organic polymer |
| CN109880027A (en) * | 2019-01-29 | 2019-06-14 | 上海交通大学 | A kind of method that semiconductor surface prepares crosslinking copolymerization organic polymer |
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