Method for treatment of single-crystalline silicon wafer surface
FIELD: semiconductor engineering; chemical treatment of single-crystalline silicon wafer surfaces chemically resistant to open air and suited to growing epitaxial semiconductor films.
SUBSTANCE: proposed method for treatment of single-crystalline silicon wafer surface positioned on Si(100) or Si(111) plane includes cleaning of mentioned surface followed by passivation with hydrogen atoms. Silicon surface is first cleaned twice by means of boiling trichloroethylene solution for 10-20 minutes involving washing with deionized water and then with ammonium-peroxide aqueous solution of following composition: 5 volumes of H2O, 1 volume of 30% H2O2, 1 volume of 25% NH4OH at 75-82 °C or with salt-peroxide aqueous solution of following composition: 6 volumes of H2O, 1 volume of 30% H2O2, 1 volume of 37% HCl at 75-82 °C, followed by three 5- or 10-minute steps of washing with deionized water; passivation with hydrogen atoms is conducted by treatment first with 5-10 mass percent HF solution and then with aqueous solution of NH4OH and NH4F mixture at pH = 7.6-7.7 for 40-60 s followed by washing with deionized water and drying out under normal conditions.
EFFECT: ability of producing wafers capable of retaining their serviceability for long time in storage and in transit, in open air, without oxidizing their surfaces.
1 cl, 3 dwg
The invention relates to semiconductor technology, and particularly to a method of chemical treatment of the surface of monocrystalline silicon wafers and can be used in the production of high-quality chemically stable in air of substrates suitable for growing epitaxial semiconductor films and to create semiconductor devices.
One of the significant problems in the technology of silicon wafers with high-purity and high-quality on the structure surface is that the surface layers are oxidized rapidly in air with the formation of oxide layers of silicon, preventing subsequent epitaxial building layers of semiconductors or semiconductor compounds.
Numerous options for fine chemical cleaning (wet chemical cleaning) of the surface of silicon wafers, which are summarized in the monograph:
Handbook of semiconductor wafer cleaning technology (Edited by Wermer Kern) Noyes Publications, New Jersey. USA 1993. 623 R.
Most fully according to the source currently studied the effect of different chemical composition of aqueous solutions containing various amounts of the following components:
- ammonia, hydrogen peroxide and deionized water (NH4OH, H2O2H2O)
- hydrochloric acid, hydrogen peroxide and deionized water (Cl, H2About2N2O),
- solutions of sulfuric (H2SO4) and hydrofluoric (HF) HF acid and other Chemical cleaning of silicon wafers from impurities is characterized by the use of a wide range of solutions, different sequence of stages of purification and varied conditions of the individual stages. From the above monograph also known processing carried out in two stages (steps):
- stage 1 - use standard solution (Standard Clean, abbreviated as SC-1), consisting of the following components: 5 volumes of N2Oh, 1 volume of N2O230%, 1 volume of NH4OH 29%. The process is carried out by heating to 70-80°With subsequent washing of the plates with deionized water. Under this treatment removes organic impurities and desorbers traces of many metals - 2 stage cleaning - use standard solution (Standard Clean, abbreviated as SC-2), consisting of the following components: 6 volumes of N2O, 1 volume of N2About230%, 1 volume of HCl 37% of the Process is carried out by heating to 70-80°With subsequent washing of the plates with deionized water. This removes ions of alkali metals, hydroxides of Al, Fe, Mg and desorbers residual ions of other metals through complexation.
After 2 stages on the surface of the product remains hydrated oxide film. For e the removal or after 1 step, or after 2 stages (preferably after 1 stage) silicon wafer is subjected to additional treatment in the acid, for example a 1%solution of HF (HF:H2O=1:50)for 15 seconds.
From US 6054393, publ. 25.04.2000, H01L 21/306 known various combinations of reagents and sequence of operations of cleaning the surface of silicon wafers using solutions of SC-1, SC-2, and HF and H2O2. The final stage of processing according to well-known solution is drying in the vapor of isopropyl alcohol, providing significant reduction of defects on the surface due to adsorption of water particles.
From US Patent 6514875, publ. 04.02.2003, H01L 21/302 known method for obtaining optically smooth surfaces of silicon wafers based on the methodology of company RCA in combination with etching and 44 wt.% the solution of KOH at 50-90°With subsequent washing in an aqueous solution of acetic acid (20-40 vol.% acid).
The above invention and as many other publications disclose decisions on the development of chemical compositions and conditions fine purification by chemical means, allowing to obtain high-purity, smooth and close to perfect on the structure of surfaces of silicon wafers, which should be immediately after cleaning to go on a technological chain epitaxial produce some or other device the century Otherwise (in the case of storage) surface of a silicon wafer quickly oxidized in the air with the formation of the oxide film of silicon, preventing the buildup of epitaxial layers of semiconductors.
1. Handbook of semiconductor wafer cleaning technology (Edited by Werner Kern) Noyes Publications, New Jersey. USA 1993. 623 R.
2. Le Than V. et. al., Fabrication ofSiGe quantum dots on a Si (100) surfaces Phys. Rev. B., 1997,v.56, No. 16, 10505-10509.
3. De Larios J.M. et al., Silicon surfaces cleaning procedures. Appl. Surf. Sci., 1987, v.30, No. 1-4, p.1-30 (Proceedings of the conference on Interfaces).
4. G.S. Higashi et. all., Ideal hydrogen termination of Si (111) surfaces., Appl. Phys. Lett., 1990, v.56, N7, p.656.
5. Jakob P., Y.J. Chabal, Chemical etching of vicinal Si (111): Dependence of the urface structure and the hydrogen termination on the pH of the etching solutions., J. Chem.Phys.,1991, v.95, No. 4, p.2897.
given the following information, which must be set for disclosure of the claimed invention.
1. Disclosed chemical composition and thermal stability of the coatings of the surfaces of Si (100) and Si (111) silicon wafers, mono-, di - and tri - hydrides of silicon, i.e. hydrogen atoms in the processing of wafers aqueous solutions of HF, aqueous buffer solutions on the basis of HF and ammonium fluoride (NH4F).
2. Studies of the influence of pH on the morphology (degree of smoothness and discontinuities) and the chemical composition of the surfaces of Si (100) and Si (111) etching:
in diluted HF (1%, pH 2);
- in mixtures of 50 wt.% aqueous HF solution with 40 wt.% aqueous solution of NH4 F: with different ratio of components:
- in a solution of HF (7:1) with a pH of 4.5-5.0 and the mixture composition: 7 volumes NH4F+1 volume of HF; (of these 1 source s);
- 40 wt.% a solution of NH4F (pH 7.8)(of these 1 source, s Fig and s, Fig).
In the experiments described in the above sources, it was found that increasing the pH of the solution from 2 to 8 accompanied by a significant increase in the rate of etching, chemical composition and morphology of the surfaces of Si (100) and Si (111).
The total output of all research is that:
1) by etching in dilute HF solutions both surfaces of Si (100) and Si (111) become loose (not smooth) and covered with a layer simultaneously mono- (≡Si-H), di (=Si=) and three- (-Si≡) hydrides of silicon;
2) raising the pH to 4.5 to 5.0 when processing wafers with orientation of the Si (100) leads to the coating surface mainly monohydride groups, and the surface morphology remains relatively loose. With limited time (≈1 min) processing the surface of Si (100) in a solution of NH4F (pH 7.8), it becomes nuclear-smooth and covered with dihydrides film, which is completely desorbed in vacuum at ≈400°C;
- when processing the surface of Si (111) in alkaline solutions with pH=9-10, when mixing chloroethanol acid (HCl)and ammonium hydroxide (NH4OH) in different the ratios obtained atomic smooth surface, perfectly covered monohydride silicon (≡Si-H), oriented perpendicular to the surface.
The known method (Le Than V. et. al., Fabrication of SiGe quantum dots on a Si (100) surfaces Phys. Rev. C., 1997, v.56, No. 16, 10505-10509) growing SiGe quantum dots on Si (100)surface. In the specified source of the dependence of the degree of roughness of the surfaces of Si (100); Si (111) and the degree of coverage of their predominantly mono-, di - and trihydrides silicon depending on the chemical compositions and pH (acidity or alkalinity) solutions, which are processed silicon wafer of the substrate. In a well-known source, the following scheme chemical treatment to obtain atomic-smooth Si (100)surface covered with a layer of dihydride silicon.
1. Cleaning solutions that are similar to the compositions of the solutions of SC-1 and SC-2.
2. Treatment in diluted 2-10% solution of HF (1-2 min) or for 1 min in a buffer solution of HF+NH4OH ("buffered" HF aqueous solution: buffered oxide etchant FIRST:7:1, pH 5) to remove from the surface layer of native silicon oxide. However, the surface is rough (not smooth), and covered with a combination of mono-, di - and trihydrides.
3. Treatment in a solution of NH4F (pH 7.8) for about 1 min, in which the surface of Si (100) becomes atomic-smooth and covered only with a layer of dihydride silicon, which is desorbed in vacuum at a temperature of ≈400°C. the ri longer processing surface becomes loose. Gaps and unresolved questions above studies in conservation (passivating) substrates for long-term storage and subsequent epitaxial capacity of semiconductors on silicon wafers - wafers:
- the scratch resistance of the surfaces of Si (100) and Si (111) oxidation, i.e. to the formation of the oxide film of silicon, which prevents epitaxy, not investigated;
- processing wafer-substrates 40 wt.% a solution of NH4F (7,8) is actually a concentrated solution inevitably leaves on the surface of islet precipitation of ammonium fluoride, which prevents further epitaxial extension of the semiconductor layers.
Closest to the claimed solution is the above-mentioned method disclosed in US 6054393, publ. 25.04.2000, H01L 21/306, whereby to clean the surface of the silicon wafer using a solution SC-1, SC-2, and HF and H2O2. The final stage of processing of the known method is drying in the vapor of isopropyl alcohol, providing significant reduction of defects on the surface due to adsorption of water particles. However, the known method does not provide the perfect structure of the plates, as well as their long-term storage without surface oxidation.
The invention aims at eliminating indicated the deficiencies and the development of the method of chemical treatment of the surface of the monocrystalline silicon wafers using aqueous alkaline buffer solution (buffer mixtures) on the basis of ammonium hydroxide (NH 4OH)and ammonium fluoride (NH4F)providing a perfect structure and passivation of the surfaces of Si (111) and Si (100) layer of hydrogen atoms, allowing long time to save and transport the plate - substrate in the air without oxidation of the surface.
The technical result is achieved in that in the method of processing the surface of a monocrystalline silicon wafer, including the effects of chemical reagents, in addition conduct passivating the surface of the wafer by coating the hydrogen atoms. The method includes the stage of cleaning the surface from organic impurities, metal impurities, removing the film native silicon oxide and the final stage of processing alkaline buffer solution of a specific composition containing NH4OH and NH4F followed by rinsing in deionized water.
The method is as follows:
Industrial output plate of monocrystalline silicon cut from a given crystallographic orientation, is subjected to chemical treatment for cleaning the surface from organic impurities, impurities of metals, removal of own film of silicon oxide, for example sequential exposure in the following fluids:
2) standard solution SC-1,
3) standard solution SC-2,
with promisc the th in deionized water after each solution.
Next, the plate is additionally Passepartout first 5 wt.% the HF solution, and then in a mixture of NH4OH and NH4F, followed by rinsing with deionized water and drying in air at normal conditions.
The following examples explain the invention.
Industrially produced single-crystal silicon wafer with orientation of the Si (100) or Si (111) or deviation of a few degrees from the Si (111) sequentially subjected to the following treatments.
1. In a boiling solution of trichloroethylene; 10 min - two-time processing.
2. Rinsing with deionized water for 5-10 minutes after each treatment.
3. In the standard solution SC-1 (5 volumes H2O, 1 volume of N2About230%, 1 volume of NH4OH 29%) when 75-82°C, 10 min, three - time processing.
4. Rinsing with deionized water for 5-10 minutes after each treatment.
5. In the standard solution SC-2 (6 volumes N2Oh, 1 volume of N2About230%, 1 volume of HCl 37%) when heated to 70-80°C, 10 min, three - time processing.
6. Rinsing with deionized water for 5-10 minutes after each treatment.
7. In 5% HF solution at room temperature for 1 minutes
8. In aqueous buffer solution containing NH4OH and NH4F with a pH of 7.6 to 7.7 at room temperature for 40-60 sec.
9. Double rinse with deionized water at room temperature is about 15-20 seconds.
10. Drying under normal conditions
Industrially produced a monocrystalline silicon wafer with orientation of the Si (100) or Si (111) or deviation of a few degrees from the Si (111) is exposed sequentially to all chemical treatments as in example 1 except for stage 8, which is carried out for 1 minute
Industrially produced a monocrystalline silicon wafer with orientation of the Si (100) or Si (111) or deviation of a few degrees from the Si (111) is subjected successively to all chemical treatments as in example 1 except for stage 8, which is carried out within 60 seconds
Figure 1 and 2 presents a typical electron diffraction from Si (100) surface and the surface of Si (111) with a deviation of a few degrees after processing, carried out according to the claimed invention (Fig 1) and after storage for 2 weeks (Figure 2). It should be noted that the qualitative picture of electron diffraction in figure 1 and Figure 2 are not changed during storage of silicon wafers in the air, at least for 2 weeks.
Notes to figure 1 and figure 2
1. The signatures indicate the sequence of operations etching of silicon wafers.
2. After each of the first three operations - consistent triple rinsing with deionised water.
3. TAE - trichloroethylene (in temp, boiling); "NH3" (H2O:sub> 2O2:NH3=5:1:1)for 10 min at 80-84°; "HCl (H2O:H2O2:HCl=6:1:1)for 10 min at 80-84°C; 5% HF for 1 min at room temp.; in a solution with a pH of 7.64 or pH 7,73 for 1 min at room temp.; 2 k - double rinsing for 15 seconds deionized water at room temp.
4. On the first three stages of the surface of the wafer in the solution is directed downward ("h"), and upon etching in HF and at pH of 7.64; 7,73 and subsequent leaching in water - up ("in").
5. 2-12 - number of silicon wafers.
6. Si (111)4gr, ie (Si (111)4°.
Figure 3 shows a typical electronography epitaxial film of silicon carbide (SiC) grown on plates - monocrystalline silicon substrates prepared in example 1 and example 2.
Epitaxial growth of SiC films was observed on the si wafers stored in air for 3-4 weeks.
Notes to Figure 3
1. The signatures indicate the sequence of operations etching of silicon wafers.
2. After each of the first three operations - consistent triple rinsing with deionised water.
3. TAE - trichloroethylene (in temp. boiling); "NH3" (H2O:H2About2:NH3=5:1:1)for 10 min at 80-84°; "HCl(H2O:H2O2:HCl=6:1:1)for 10 min at 80-84°C; 5% HF for 1 min at room temp.; in a solution with a pH of 7.64 or pH 7,73 for 1 min at room temp.; 2 k - double rinsing for 15 seconds deionized water at room temp.
4. N the first three stages of the surface of the wafer in the solution is directed downward ("n"), while etching in HF and at pH of 7.64; 7,73 and subsequent leaching in water - up ("in").
5.03-05 - the number of silicon wafers
The method of processing the surface of a monocrystalline silicon wafer, oriented along the plane of the Si(100) or Si(111), including the specified cleaning the surface with subsequent passivation by hydrogen atoms, characterized in that the surface cleaning of silicon carried out first in a boiling solution of trichloroethylene in 10-20 min - dual treatment with rinsing with deionized water for 5-10 minutes after each treatment, and then in an aqueous ammonia-peroxide solution composition: 5 volumes of N2Oh, 1 volume of N2O230%, 1 volume of NH4OH 25% 75-82°or in aqueous hydrochloric peroxide solution composition: 6 volumes of N2Oh, 1 volume of H2O230%, 1 volume of HCl 37% at 75-82°With subsequent speed triple rinse with deionized water for 5-10 min at each step and the passivation by hydrogen atoms is performed by the first processing 5-10 wt.% the HF solution, and then an aqueous solution of a mixture of NH4OH and NH4F with a pH of 7.6 to 7.7 for 40-60 with subsequent washing with deionized water and drying under normal conditions.
FIELD: semiconductor device manufacture; pre-heat cleaning of silicon substrate surfaces from organic and mechanical contaminants.
SUBSTANCE: proposed method for cleaning silicon substrates includes their double-stage treatment in two baths filled with two solutions: first bath is filled with solution of sulfuric acid H2SO4 and hydrogen peroxide H2O2 in H2SO4 : H2O2 = 10 : 1 proportion at temperature T = 125 °C; other bath is filled with solution of aqueous ammonia NH4OH, hydrogen peroxide H2O2, and deionized water H2O in proportion of NH4OH : H2O2, : H2O at temperature T = 65 °C. Resulting amount of dust particles is not over three.
EFFECT: ability of removing all organic and mechanical contaminants and impurities from silicon substrate surface, reduced substrate treatment time.
FIELD: manufacturing semiconductor devices including removal of resistive mask from silicon wafer surfaces upon photolithographic operations.
SUBSTANCE: proposed method for removing resistive mask includes silicon wafer treatment upon photolithographic operations to remove photoresist from surface; treatment is conducted in two stages; first stage includes treatment in sulfuric acid (H2SO4) and hydrogen peroxide (H2O2) solution of 3 : 1 proportion at temperature T = 125 °C for 5 minutes; second stage includes washing first in warm deionized water (H2O) at T = 65-70 °C for 5 minutes followed by washing in two baths, each having spillover points in four sides, at water flowrate of 400 l/h and wash time of 5 minutes in each bath; wafers are checked for adequate cleaning by focused incident light beam at maximum six luminous points.
EFFECT: reduced number of operations required to remove resistive mask, ability of attaining clean surfaces free from photolithographic contaminants.
FIELD: electronics; semiconductor devices and methods for etching structures on their wafers.
SUBSTANCE: plasmochemical etching of material is conducted by way of acting on its surface with ion flow of plasma produced from plasma forming gas filling evacuated camber, electron beam being used to act upon plasma forming gas for plasma generation. Constant longitudinal magnetic field with flux density of 20-40 Gs is built on axis, plasma-generating gas pressure is maintained within chamber between 0.01 and 0.1 Pa, and electron beam at current density of 0.1-1 A/cm2 ensuring ignition of beam-plasma discharge is used. Etching condition (energy and ion current density) can be controlled ether by modulating electron beam with respect to speed or by varying potential of discharge collector.
EFFECT: enhanced etching efficiency (speed) and quality of etching structures on semiconductor material surface: high degree of etching anisotropy preventing etching under mask, minimized material structure radiation defects brought in during etching.
2 cl, 1 dwg
FIELD: semiconductor device manufacture; silicon-wafer surface post-oxidation etching, boron and phosphor sublimation.
SUBSTANCE: proposed method for removing crystallites from silicon wafer surface includes pre-oxidation of wafer surface in oxygen environment at temperature of 850 °C for 20 minutes followed by chemical treatment in hydrofluoric acid and ammonium fluoride solution, proportion of ingredients being 1 : 6.
EFFECT: provision for complete removal of crystallites from silicon wafer surface after heat treatment, reduced wafer treatment time.
FIELD: plasma reaction gas, its production and application.
SUBSTANCE: proposed plasma reaction gas has in its composition chain-structure perfluoroalkyne incorporating 5 or 6 atoms of carbon, preferably perfluorine-2-pentyne. This plasma reaction gas can be found useful for dry etching to produce precision structure, for plasma chemical precipitation from vapor phase, for producing thin film, and for plasma chemical incineration. Plasma reaction gas is synthesized by way of bringing dihydrofluoroalkyne or monohydroalkyne in contact with basic compound.
EFFECT: enhanced economic efficiency of highly selective gas production for plasma reaction on industrial scale.
FIELD: electronic engineering; group treatment of flat glass substrates.
SUBSTANCE: proposed method for washing and drying flat glass substrates includes following operations: substrate held in magazine is placed in washing bath filled with deionized water, washed out, and then slowly taken out of magazine; while substrates are being taken out of water, they are washed and dried out in nitrogen and organic solvent vapors; upon such treatment substrates are secured in extreme upper position, whereupon magazine is moved up, washed, and dried in the same way as substrates; treated substrates are placed in extreme upper position into magazine and the latter is then removed together with substrates from drying chamber. Device implementing proposed method is also given in invention specification.
EFFECT: enhanced quality of substrate treatment; ability of process automation in flexible production line; simplified design.
2 cl 5 dwg
FIELD: electronic engineering; treatment of semiconductor materials including semiconductor silicon wafers.
SUBSTANCE: proposed solution for electrochemical dissolution of silicon has ammonia chloride and urea used as solvent, their proportion being as follows, mass percent: ammonia chloride, 7 - 10; urea, 90 - 93. Provision is made for controlling rate of silicon etching at current output close to 100%.
EFFECT: ability of controlling silicon etching rate and of eliminating environmentally detrimental substances in solution.
FIELD: production of dirt-free laser mirrors.
SUBSTANCE: proposed method for producing dirt-free surfaces of materials chosen from group incorporating GaAs, GaAlAs, InGaAs, InGaAsP, and InGaAs on mirror facets of chip for GaAS based laser resonators includes shearing of laser mirror facet in ambient atmosphere incorporating normal air, dry air, or dry nitric media. Oxides and other pollutants produced in the course of ambient atmosphere impact on mirror facets are removed by dry etching in vacuum. Then natural nitride layer is grown on mirror facets using nitrogen treatment. Such facet treatment ensures minimized light absorption and surface recombination.
EFFECT: facilitated procedure, enhanced economic efficiency and yield due to high reproducibility.
37 cl, 5 dwg
FIELD: microelectronics, micro- and nano-technology.
SUBSTANCE: proposed method for producing submicron and nanometric structure includes formation of embossed structures on substrate surface, application of film to reduce embossed structure size to submicron and nanometric dimensions, and etching, anisotropic and selective relative to film material and source embossed layer, in chemically active plasma of structure obtained together with substrate material until embossed structure of submicron and nanometric dimensions, twice as deep as its width, is obtained.
EFFECT: provision for transferring mask pattern to bottom layer of substrate measured in terms of submicron and nanometric values.
2 cl, 3 dwg
FIELD: microelectronics techniques, micro- and nano-technologies, namely design of plasmo-chemical reactor in which processes for etching and depositing different materials are realized.
SUBSTANCE: plasmo-chemical reactor includes reaction chamber, inductor, substrate holder, thin-wall cylindrical metallic shield and heat removal struts whose properties provide rate of temperature change of screen and time period for setting is stationary temperature. Thin-wall cylindrical metallic screen is secured to heat removal struts inside reaction chamber and it is spaced from walls of reaction chamber.
EFFECT: possibility for separate control of basic content of plasma composition and for depositing high-quality coating.
2 cl, 1 dwg, 1 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to a method for purifying octafluorocyclobutane. Method is carried out by interaction of crude octafluorocyclobutane containing impurities with the impurity-decomposing agent at increased temperature and then with adsorbent that is able to eliminate indicated impurities up to the content less 0.0001 wt.-% from the mentioned crude octafluorocyclobutane. Impurity-decomposing agent comprises ferric (III) oxide and compound of alkaline-earth metal in the amount from 5 to 40 wt.-% of ferric oxide and from 60 to 95 wt.-% of compound of alkaline-earth metal as measured for the complete mass of the impurity-decomposing agent. Ferric (III) oxide represents γ-form of iron hydroxyoxide and/or γ-form of ferric (III) oxide. Impurity represents at least one fluorocarbon taken among the group consisting of 2-chloro-1,1,1,2,3,3,3-heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-heptafluoropropane, 1-chloro-1,2,2,2-tetrafluoroethane, 1-chloro-1,1,2,2-tetrafluoroethane, 1,2-dichloro-1,1,2,2-tetrafluoroethane, hexafluoropropene and 1H-heptafluoropropane. Adsorbent represents at least one of representatives taken among the group including activated carbon, carbon molecular sieves and activated coal. Crude octafluorocyclobutane interacts with the mentioned impurity-decomposing agent at temperature from 250oC to 380oC. Invention proposes gas, etching gas and purifying gas including octafluorocyclobutane with purity degree 99.9999 wt.-% and above and comprising fluorocarbon impurity in the concentration less 0.0001 wt.-%. Invention provides enhancing purity of octafluorocyclobutane.
EFFECT: improved purifying method.
26 cl, 13 tbl, 10 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to a method for purifying octafluoropropane. Method is carried out by interaction of crude octafluoropropane comprising impurities with the impurity-decomposing agent at increased temperature and then with adsorbent that are able to remove indicated impurities up to the content less 0.0001 wt.-% from indicated crude octafluoropropane. The impurity-decomposing agent comprises ferric (III) oxide and compound of alkaline-earth metal in the amount from 5 to 40 wt.-% of ferric oxide and from 60 to 95 wt.-% of compound of alkaline-earth metal as measured for the complete mass of the impurity-decomposing agent. Ferric (III) oxide represents γ-form of iron hydroxyoxide and/or γ-form of ferric (III) oxide. Impurities represent at least one compound taken among the group consisting of chloropentafluoroethane, hexafluoropropene, chlorotrifluoromethane, dichlorodifluoromethane and chlorodifluoromethane. Adsorbent represents at least one substance taken among the group consisting of activated coal, molecular sieves and carbon molecular sieves. Crude octafluoropropane comprises indicated impurities in the amount from 10 to 10 000 mole fr. by mass. Invention proposes gas, etching gas and purifying gas comprising octafluoropropane with purity degree 99.9999 wt.-% and above and containing chlorine compound in the concentration less 0.0001 wt.-%. Invention provides enhancing purity of octafluoropropane.
EFFECT: improved purifying method.
13 cl, 11 tbl, 12 ex
FIELD: polymer materials.
SUBSTANCE: method of applying high-resolution image of functional layers, e.g. for applying lithographic mask or other functional layers, comprises polymerization of monomers from vapor phase under action of finely focused electron beam with energy 1 to 1000 keV followed by injection of monomer vapors at pressure from 10-4 to 10 torr. Electron beam is introduced into working chamber through a small opening in membrane, which enables avoiding scattering of electrons on membrane and, at the same time, maintaining monomer vapor pressure in working chamber high enough to ensure acceptable growth time for thickness (height) of image line. Preferred image applying conditions are the following: electron energy in electron beam 10 to 500 keV and monomer vapor pressure 0.001 to 10 torr. For electron beam diameter 50 nm, image width 100-150 nm can be obtained. When improving electron beam focusing, accessible electron beam diameter may be further diminished.
EFFECT: enabled high-resolution image of functional layers directly from monomer in single-step "dry" process without using any solvents.
2 cl, 2 dwg, 8 ex
FIELD: semiconductor microelectronics; high-degree surface cleaning technologies.
SUBSTANCE: proposed method can be used in resource and energy conservation environmentally friendly and safe technology for integrated circuit manufacture, removal of positive photoresist from wafer surface, electrochemical etching of silicon, and degreasing of surfaces. Si surface is cleaned by detergent NH4HF2 of 0.1 - 4 M concentration activated by ozone at anode current density of 1 - 2 kA/m2, and waste solution is cleaned and activated by sequentially passing it through electrolyzer cathode and anode chamber.
EFFECT: enhanced quality and effectiveness of photoresist removal from semiconductor surface.
2 cl, 2 dwg
FIELD: plasma-chemical treatment of wafers and integrated circuit manufacture.
SUBSTANCE: proposed device that can be used in photolithography for photoresist removal and radical etching of various semiconductor layers in integrated circuit manufacturing processes has activation chamber made in the form of insulating pipe with working gas admission branch; inductor made in the form of inductance coil wound on part of pipe outer surface length and connected to high-frequency generator; reaction chamber with gas evacuating pipe, shielding screens disposed at pipe base, and temperature-stabilized substrate holder mounted in chamber base. In addition device is provided with grounded shield made in the form of conducting nonmagnetic cylinder that has at least one notch along its generating line and is installed between inductor and pipe; shielding screens of device are made in the form of set of thin metal plates arranged in parallel at desired angle to substrate holder within cylindrical holder whose inner diameter is greater than maximal diameter of wafers being treated. Tilting angle, quantity, and parameters of wafers are chosen considering the transparency of gas flow screen and ability of each wafer to overlap another one maximum half its area. In addition substrate holder is spaced maximum four and minimum 0.6 of pipe inner diameter from last turn of inductance coil; coil turn number is chosen to ensure excitation of intensive discharge in vicinity of inductor depending on generator output voltage and on inner diameter of pipe using the following equation:
where n is inductance coil turn number; U is generator output voltage, V; Dp is inner diameter of pipe, mm.
EFFECT: enhanced speed and quality of wafer treatment; reduced cost due to reduced gas and power requirement for wafer treatment.
1 cl, 6 dwg, 1 tbl
SUBSTANCE: proposed method that can be used for photolytic etching of wafers in the course of manufacture of very large-scale integrated circuit includes etching of SiO2 surface in sulfur hexafluoride under action of vacuum ultraviolet emission of deuterium-vapor lamp. Argon is introduced in addition into etching gas.
EFFECT: enhanced selectivity of silicon dioxide etching with respect to monocrystalline and polycrystalline silicon.
3 cl, 1 tbl
FIELD: process equipment for manufacturing semiconductor devices.
SUBSTANCE: plasma treatment chamber 200 affording improvement in procedures of pressure control above semiconductor wafer 206 is, essentially, vacuum chamber 212, 214, 216 communicating with plasma exciting and holding device. Part of this device is etching-gas source 250 and outlet channel 260. Boundaries of area above semiconductor wafer are controlled by limiting ring. Pressure above semiconductor wafer depends on pressure drop within limiting ring. The latter is part of above-the-wafer pressure controller that provides for controlling more than 100% of pressure control area above semiconductor wafer. Such pressure controller can be made in the form of three adjustable limiting rings 230, 232, 234 and limiting unit 236 on holder 240 that can be used to control pressure above semiconductor wafer.
EFFECT: enhanced reliability of pressure control procedure.
15 cl, 13 dwg
FIELD: manufacture of microelectronic and nanoelectronic devices.
SUBSTANCE: selective etchant of AlAs and AlGaAs layers relative to GaAs has iodine I2 and organic solvent wherein iodine I2 is dissolved, proportion of mentioned components being as follows, mass percent: iodine, 0.1 - 4; organic solvent, 96 - 99.9. Isopropyl alcohol or acetone can be used as organic solvent. Enhanced selectivity of etching AlAs and AlGaAs layers including those with low Al content (below 40%), as well as their high selectivity relative to InAs and InGaAs are attained at room temperature.
EFFECT: ability of using proposed etchant in nanotechnology for separating upper layers in the order of several single layers.
FIELD: engineering of semiconductor devices.
SUBSTANCE: invention concerns method and device for etching dielectric, removing etching mask and cleaning etching chamber. In etching chamber 40 semiconductor plate 56 is positioned. Dielectric 58 made on semiconductor plate is subjected to etching, using local plasma, produced by special device for producing local plasma during etching process. Mask for etching 60 is removed by means of plasma from autonomous source 54, generated in device for producing plasma from autonomous source connected to etching chamber. Etching chamber after removal of semiconductor plate is subjected to cleaning, using either local plasma, or plasma from autonomous source. To achieve higher level of cleaning, it is possible to utilize a heater, providing heating for chamber wall.
EFFECT: increased efficiency.
2 cl, 4 dwg
FIELD: technology for producing semi-penetrable membranes for molecular filtration of gas flows and for division of reaction spaces in chemical reactors.
SUBSTANCE: method for producing gas-penetrable membrane includes two-sided electro-chemical etching of monocrystalline plate made of composition AIIIBV of n conductivity type or of semiconductor AIV with width of forbidden zone E≥1,0 electron volts and alloying level 1017-1020 1/cm3. Modes of aforementioned etching are set, providing for generation of simultaneously porous layers, while etching process is performed until moment of spontaneous stopping of electro-chemical process and generation of solid separating layer of stationary thickness on given part of plate area, determined using sharp bend on the curve of temporal dependence of anode current.
EFFECT: gas membrane, produced in accordance to method, has increased penetrability for molecules of light gases and increased selectivity characteristics at room temperature.
2 cl, 3 dwg, 3 ex