The method of cleaning the surface
(57) Abstract:Usage: microelectronics cleaning the surface of the wafer during fabrication of very large scale integrated circuits. Essence: place the cleaned wafer in a vacuum chamber and treated with the surface of the plate intense jet bioaerosol nitrogen and argon, with the addition of impurity oxygen in the presence of ultraviolet radiation with a wavelength less than 200 nm. The technical result of the invention is to improve the treatment efficiency of organic pollutants surface with smooth terrain. table 1. The scope of the invention is microelectronics, namely the methods of cleaning the surface of the wafer during fabrication of very large scale integrated circuits (VLSI).The known method of surface cleaning from mechanical impurities, which consists in processing the surface being cleaned by compressed carbon dioxide - CO2that when extending into the space turns into particles of dry ice and these particles effectively cleans the surface from mechanical particles and organic impurities .However, it is not effectively cleans the surface with a complex profile is the first gas is a good solvent for many organic compounds, including hydrocarbons, and it is difficult to clean.The disadvantage of this method is that after such surface treatment is not excluded the possibility of contamination by traces of oils contained in the CO2and the carbon dioxide by their chemical nature is contaminating impurity when creating VLSI.Closest to the proposed invention is a method of cleaning a surface using a cryogenic aerosol, including room cleaned plates in high-purity vacuum chamber and processing the surface of an intense jet of liquefied gases argon and nitrogen at a temperature close to the melting point of argon. When this occurs, the surface treatment spray liquid nitrogen and particulate solid argon, which effectively clean the surface from mechanical impurities, including submicron particles and polymer residues after reactive-ion etching (RIT) . Remote spray with plate particles and polymers are removed from the chamber with aerosol otkaznuyu system. This method is used for surface cleaning of silicon wafers from sub-micron particles, organic sediments and films visockaite, that it is ineffective when cleaning the surface of organic trace contaminants with smooth profile.The task to be solved by the invention is the achievement of the technical result consists in an additional cleaning of the surface from organic trace contaminants with smooth profile. This technical result is achieved in the method of cleaning the surface, including the location of the cleaned plates in high-purity vacuum chamber and simultaneous treatment of the surface being cleaned intense jet craaaaaazy argon and nitrogen mixed with oxygen and ultraviolet radiation with a wavelength less than 200 nm.Thus, the distinctive features of the invention are additional processing of the cleaned surface with ultraviolet radiation with a wavelength less than 200 nm with the introduction bioaerosol argon and nitrogen impurities of oxygen.Listed distinctive features can achieve the technical result.The process of cleaning the surface is as follows. The cleaned plate is placed in a vacuum chamber and simultaneously process the stream bioaerosol argon and nitrogen with primes and and nitrogen and has energy, sufficient for the destruction of chemical bonds of organic compounds and in the presence of traces of oxygen in quantities do not significantly affect the attenuation of the intensity of the flux of ultraviolet radiation on the treated surface, and for the intensive oxidation of organic compounds. Therefore, this additional processing leads to clean the surface from organic impurities with smooth terrain. The source of ultraviolet radiation can be situated directly in the vacuum chamber, and beyond. In the latter case, the radiation from the source is directed onto the cleaned wafer into the chamber through a window made of transparent to the wavelengths of material, such as sapphire, calcium fluoride, magnesium fluoride. As a source of ultraviolet radiation may be applied excimer laser with a wavelength less than 200 nm, lamp sources of intense ultraviolet radiation with a wavelength less than 200 nm (e.g., dauterive discharge lamp, a mercury low pressure lamp with a quartz envelope), or this ultraviolet radiation can be formed directly in the cell by initiating in the residual gases vysokotrave glass sealed on the surface of the camera above the table.An example implementation of the method.Chemically cleaned silicon wafer was applied 1% solution of S1813 photoresist in acetone. Then the plates were dried at 100oWith 1 min on a hot plate. Prepared plates were divided into six groups. The first group of plates was analyzed for the presence of carbon by the method of secondary ion mass spectrometry (Sims). Plates of the second group was placed on a table in a vacuum chamber. The chamber was pumped turbomolecular pump. Then the plate was processed in a spray jet of bioaerosol consisting of drops of liquid nitrogen, mixed with particles of solid argon (10%), with continuous pumping, and the treated area of the plate was analyzed for the presence of carbon by the method of VIMS. Plates of the third group was placed on a table in a vacuum chamber. The chamber was pumped turbomolecular pump. Then the plate was processed in a spray jet of liquid nitrogen with a mixture of argon (10%) and oxygen (1%) under continuous pumping, and the treated area of the plate was analyzed for the presence of carbon by the method of VIMS. Plate of the fourth group were placed on a table in a vacuum chamber. Camera otkazivani power of 350 W and a spray jet of bioaerosol, consisting of drops of liquid nitrogen, mixed with particles of solid argon (10%), with continuous pumping. The treated area of the plate was analyzed for the presence of carbon by the method of VIMS. Plate of the fifth group was placed on a table in a vacuum chamber. The chamber was pumped. Then the Central part of the plates were processed VUV radiation from the deuterium lamp power of 350 W and a spray jet of bioaerosol consisting of drops of liquid nitrogen, mixed with particles of solid argon (10%) and gaseous oxygen (1%), with continuous pumping. The treated area of the plate was analyzed for the presence of carbon by the method of VIMS. In all experiments, the jet of atomizing gas was supplied to the plate surface at an angle close to 45o. The processing time for the VUV radiation and jet bioaerosol was five minutes. Sixth group of plates washed off the traces of photoresist in acetone, subjected to liquid chemical processing in CARO+PAIRS and analyzed in the presence of carbon by the method of VIMS. The main results of the Sims analysis shown in the table. As the wine from the table, the surface of the wafer from the first group covered by the carbon with the relative intensity of the signal at the level of 1017. The first surface. Plates of the second group have a lower concentration of carbon in comparison with plates from the first group (at the level of 1014), about the same concentration of carbon have and plates of the third group. Plate of the fourth group has a much lower concentration of carbon on the surface (relative signal intensity carbon 1010), and the plate of the fifth group have an average concentration of carbon on the surface of the minimum of all the groups of plates, in addition to the plates of the fourth group, i.e. the highest degree of purification.LITERATURE
1. Similar: Stuart A. Hoenig / Cleaning Surfaces with Dry lce//Compressed Air Magazine, August 1986, p.22-24.2. Prototype: W. T. McDermott, Ockovic R. C., Wu J. J., Cooper D. W., Snwarz A. , Wolfe H. L. Patent EP 0461476 A2 from 29.05.91, H 01 L 21/306, priority 05.06.90, US 534810. The method of cleaning the surface including the location of the cleaned wafer in a vacuum chamber and processing the surface of the plate intense jet bioaerosol nitrogen and argon, characterized in that bioaerosol nitrogen and argon is injected admixture of oxygen and subjecting the surface to be cleaned simultaneously with the processing of the stream bioaerosol processing by ultraviolet radiation with a wavelength less than 200 nm.
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