Method of applying high-resolution image of functional layers based on thin polymer films on the surface of solids
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
The invention relates to the field of polymer chemistry and can be used in electronic equipment, for example, for applying a lithographic mask or other functional layers.
A known method of applying image lithographic masks used in the manufacture of integrated circuits, based on the drawing on the plate surface of the semiconductor layer of polymeric resist followed by the application of a latent image by exposing the resist astrosociology the electron beam and the manifestation of this image by processing the resist selective solvent [1. Brody, Jora. The physical basis for microtechnology. M: Peace. 1985. 2. Are, Teaserama. Lithographic processes. M.: Higher school, 1990.]. The main disadvantages of this method are the necessity of using large quantities of organic solvents and the multistage process of drawing the image. Also known dry one-step method of applying to the surface of solids solid polymer films by polymerization of the monomer from the vapor phase under the action of the electron beam [3. Masruq, Angiari, Avery, Vasiliev, Yegads, Entelechon. The method of applying a thin polymer layers on the surface of a solid phone Application for patent of the RF No. 2000115378 from 19.06.2000. The positive decision from 19.02.2002.]. One is to this technique does not allow to apply the high-resolution image is primarily due to nesfokusirovannost used electron beam, and a membrane separating the working chamber from pairs of monomer from the camera with the electron emitter.
Closest to the claimed method is drawing the image by the polymerization of methyl methacrylate from the vapor phase under the action of ultraviolet laser beam [4. J.Y.Tsao, D.J.Ehrlich. UV laser photopolymerization of volatile surface-adsorbed methyl methacrylate. Appl.Phys.Lett. 1983. Vol.42. N12. P.997]. The main disadvantage of this method (prototype) is not high enough resolution (precision drawing the image), mainly due to the known physical limitations, under which the line width in the applied image may not be less than the wavelength of the used radiation [1, 2]. In  was used radiation of an argon laser with a wavelength of 257,2 nm (0,257 μm). This was the resulting image lithographic mask minimum line width δ from 1 to 5 microns.
The technical objective of the proposed method is to increase the resolution (precision) of drawing the image.
The goal of the project is achieved by the use to initiate polymerization on the surface of the substrate ostrovoduzhnogo electron beam when the electron energy in the beam 1-1000 Kev, preferably 1-500 Kev. The effective wavelength of these electrons in accordance with kungfu theory which is 10 -2-10-3nm [1, 2]. Such a beam with use of special devices can be focused to a size of 1-10 nm. Accordingly, the inventive method has a theoretical limit of resolution (precision) of drawing the image about 10 nm (0.01 µm). However, the high resolution can be realized only if direct (membraneless) the input of the electron beam in the chamber for drawing the image. Accordingly, the working chamber in which is placed a substrate and introducing a couple of monomer must contain a hole for direct input of the focused electron beam. When writing the electron beam through the membrane due to the scattering of electrons in the membrane is a significant broadening applied to the solid polymer substrate of the image.
The energy range of the electrons in the beam E is determined by the following considerations. When E is less than 1 Kev deteriorating the focusing of the electron beam and increases the backscattering of electrons from the substrate, which leads to the broadening caused by the image. Where more than 1000 Kev complicated design of the electron-beam system and decreases the speed of drawing the image (due to the reduction of the cross section of electron capture substrate).
For polymerization can be used in a wide range of monomers. The vapour pressure of the monomer in the working chamber should be 10-4-10 Torr, predpochtitelno of 0.001-10 Torr. At pressures less than 10-4Torr, is too small, the speed of drawing the image. At pressures of the big 10 Torr, due to significant leakage of vapors of the monomer from the working chamber, unable to obtain the necessary vacuum in the chamber with the electron emitter, which forms an electron beam.
As substrates can be used plates from different materials, ensuring the effective discharge of the charge from the surface, in particular wafers of monocrystalline silicon, or the same plate with a thin (about 0.1 μm) surface layer of silicon dioxide or silicon wafers with deposited them with a layer of gold, or a thin (0.1 to 0.5 μm) plates, silicon nitride, etc. by the Claimed method on the surface of the wafer can be formed image of the different geometry.
The method of applying image is implemented as follows.
Example 1. Inside the metal vacuum cell with a hole the size of 0.3×0.3 mm to enter the e-beam is placed a solid substrate in the form of a wafer of monocrystalline silicon with a thickness of 0.5 mm Cell vacuumized at room temperature. An electron beam is focused onto the surface of the plate to the size of the cross section of the beam about 0.1 μm and scans in a straight length of 100 μm when sweep time 20 MS. The energy of the electrons in the beam E=40 Kev, current of the beam - eye is about 1 in. After that enter the cell pair of tetrafluoroethylene at a pressure of about 0.05 Torr and conduct irradiation for 2 minutes as a result, the surface of the plate is formed by a continuous line of polytetrafluoroethylene with smooth contours of length L=100 μm and a thickness (height) h=20 nm. Line in cross section has the shape of a trapezoid. The line width at half-height δ=210 nm. The average rate of growth of the thickness (height) of the line w=10 nm/min
Example 2. Same as in example 1, but the duration of irradiation in the presence of vapors of tetrafluoroethylene is 6 minutes When it is formed (smfh.) the solid line of polytetrafluoroethylene with the following parameters: L=100 ám, h=50 nm, δ=240 nm, w=8 nm/min
Example 3. Same as in example 1, but in a cell, enter a pair of methacrylic acid at a pressure of 0.05 Torr. E=20 Kev. The current in the beam of 0.2. The time sweep of the beam 13 C. the exposure Time of the plate silicon nitride was 4 minutes Received continuous line of poly (methacrylic acid) with the following parameters: L=100 ám, h=60 nm, δ=180 nm, w=15 nm/min
Example 4. Same as in example 3, but the exposure time was 17 minutes Received continuous line of poly (methacrylic acid) with the following parameters: L=100 ám, h=200 nm, δ=250 nm, w=12 nm/min
Example 5. Same as in example 1, but in a cell with a hole of 0.1×0.1 mm impose pairs of methyl methacrylate at a pressure of 1 Torr and conduct radiation p is ckom of electrons with energy of 100 Kev for 5 minutes When this beam scans along a straight length of 80 μm. The obtained solid line polymethyl methacrylate with the following parameters: L=80 ám, h=50 nm, δ=120 nm, w=10 nm/min
Example 6. Same as in example 1, but in a cell, enter a pair of methyl acrylate at a pressure of 0.005 Torr and carry out the irradiation of the electron beam with an energy of 100 Kev and a beam of 0.05 μm for 15 min Obtained solid line from polymethylacrylate with the following parameters: L=100 ám, h=25 nm, δ=100 nm, w=2 nm/min
Example 7. Same as in example 1, but the substrate used plate of monocrystalline silicon with a sawed at it with a layer of gold of a thickness of about 0.1 μm. Parameters marked with lines similar to those given in example 1.
Example 8. Same as in example 1, but the substrate used is a plate of silicon nitride with a thickness of 0.1 μm. Parameters marked with lines similar to those given in example 1.
Using the proposed method allows to apply high-resolution image of the functional layers directly from the monomer in single-stage "dry" process without the use of any solvents. According to the above examples, the line width of the plotted image is 100-250 nm, which is substantially less than in the prototype. Achieved in the proposed method, the line width can be reduced, in particular, due to the beam is she focusing of the electron beam. The inventive method also allows you to get additional technological advantages in comparison with the prototype provided by the use of an electron beam, in particular a wide possibility of automatic control of the parameters of the electron beam and consequently the speed of application, the topology and properties of the formed polymer image [1, 2].
1. The method of applying to the surface of solids of high-resolution images of the functional layers based on thin polymer films, which consists in the fact that the image of different geometry form directly from the monomer by polymerization of the vapor phase under the action of radiation, characterized in that on the surface of a solid body exercise membraneless direct input ostrovoduzhnogo beam of electrons with energy of 1-1000 Kev, followed by the monomer vapor at a pressure of 10-410 Torr.
2. The method according to claim 1, wherein the drawing is conducted preferably at a pressure of vapor of the monomer of 0.001-10 Torr and the energy of the electrons in the beam 10-500 Kev.
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: 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: producing of polymer products from methacrylate and other (meth)acrylate monomers.
SUBSTANCE: continuous method for production of polymer products includes radical polymerization of methylmethacrylate systems or its mixture with other (meth)acrylate monomers or vinylacetate in presence of radical polymerization initiator to produce polymer-monomer system followed by physico-mechanical treatment (e.g. extrusion) and simultaneous depolymerization. Method of present invention makes it possible to carry out polymerization with conversion of approximately 100 %.
EFFECT: polymer products with improved physicochemical properties; simplified polymerization process.
11 cl, 8 ex, 1 tbl