Method of polishing of the silver chloride crystals

FIELD: chemical industry; other industries; methods of polishing of the silver chloride crystals.

SUBSTANCE: the invention is pertaining to the field of manufacture of the optical elements and may be used in the infrared engineering. The method provides for the abrasive polishing of AgCl crystals with the sodium thiosulfate water solution and with the finishing washing of the treated article in 30-40 % solution of 2-methyl-2-aminopropane (СН3)3CNH2 in ethanol С2Н5ОН and the following dry final polishing. The method ensures the high-accuracy polishing of the articles made out of the silver chloride crystals and the high quality of the polished surfaces.

EFFECT: the invention ensures the high-accuracy polishing of the articles made out of the silver chloride crystals and the high quality of the polished surfaces.

2 ex

 

The invention relates to the manufacture of optical elements and can be used in infrared technology.

Silver chloride AgCl is widely used for the manufacture of optics infrared range. In the manufacture of products from crystals of AgCl main problem is their machining. The chloride of silver is very soft and ductile material, making it impossible mechanical polishing with abrasives, which is the main method of manufacture of various optical elements made of other materials.

The known method of chemical-mechanical polishing crystals of AgCl [P.Glesecke, N..Colthup. Method of polishing silver chloride. U.S. patent No. 2528224 - prototype], including abrasive polishing with an aqueous sodium thiosulfate solution and subsequent dry finish polishing.

An aqueous solution of sodium thiosulfate Na2S2About3well dissolves the chloride of silver, and thus the first stage of the process is chemical-mechanical polishing.

The main disadvantage of the prototype method is that when moving the product on dry polishing pad for final polishing is not terminated, the reaction of sodium thiosulfate and chloride of silver, because after the first stage of the process on the surface of the product remains disturbed layer imbibed with an aqueous solution of Na2S2O3. The result continues the origin Taiwan is going uncontrolled change of the geometrical characteristics (thickness, the flatness of the surface of the product, which makes it impossible for high-precision polishing. In addition, in the reaction described by the equation

AgCl+2Na2S2O3=Na3[Ag(S2O3)2]+NaCl (1)

on the surface and in the volume of the damaged layer formed microcrystals of sodium chloride NaCl. The hardness of sodium chloride is approximately two times higher than that of silver chloride (hardness NaCl and AgCl, as measured by the method of Knappa, respectively 18,8 and 9.5 kgf/mm2[Alt, Wesbanco, Nwireless etc., Acoustic crystals. The Handbook. M., "Nauka", 1982, p.54, 118]). Therefore, when a dry finish polishing on the surface of silver chloride are scratches.

Washing the product after the first stage of polishing water and other solvents sodium thiosulfate does not terminate the reaction described by equation (1), because the reaction is not on the surface and in the volume of the damaged layer.

The objective of the proposed method is high-precision polishing products from crystals of silver chloride and the provision of high quality polished surfaces.

This problem is solved in the proposed method of polishing crystals of silver chloride, comprising abrasive polishing with an aqueous sodium thiosulfate solution and subsequent dry finish polishing, due to the fact that AB is Asuna polishing with an aqueous solution of sodium thiosulfate is terminated by washing the treated product in a 30-40% solution of 2-methyl-2-aminopropane (CH 3)3CNH2in ethanol With2H5OH.

2-methyl-2-aminopropan is an effective inhibitor of the reaction of sodium thiosulfate with silver chloride and easily gets damaged layer on the surface of workpiece. Therefore, the reaction described by equation (1), stops almost instantly. The result is not a spontaneous change of the geometrical dimensions of the product. At the same time preventing the formation of micro-crystals of NaCl.

The proposed method can be polished flat surface of the AgCl crystals, providing the tolerances on the thickness of the product to ±0.005 mm, and the deviation from flatness to 0.25 of the interference rings. The class of clean polished surfaces (GOST 11141-76) corresponds to the PIII. The achievement of these parameters was not possible when using the prototype method.

The concentration of 2-methyl-2-aminopropane in ethanol was chosen experimentally. When the content of (CH3)3CNH2less than 30% of the reaction of silver chloride with sodium thiosulfate slowed but not stopped completely. The increase in the content of 2-methyl-2-aminopropane in ethanol to a level more than 40% does not give further positive effect.

Example 1

Procurement from a crystal of silver chloride in the form of a disc is polished on velvet with diamond powder ACM 1/0 (the OST 9206-80) and 20% aqueous sodium thiosulfate solution. After this stage of the process the workpiece is washed in a 30% solution of 2-methyl-2-aminopropane in ethanol and subjected to a dry finish polishing on silk with diamond powder ACM 0,5/0 (GOST 9206-80). Custom laser window of AgCl.

Example 2

Procurement from a crystal of silver chloride in the form of a disc is polished on velvet with diamond powder ACM 1/0 (GOST 9206-80) and 5% aqueous sodium thiosulfate solution. After this stage of the process the workpiece is washed in 40% solution of 2-methyl-2-aminopropane in ethanol and subjected to a dry finish polishing on silk with diamond powder ACM 0,5/0 (GOST 9206-80). Custom laser window of AgCl.

Method of polishing crystals of silver chloride, comprising abrasive polishing with an aqueous sodium thiosulfate solution and subsequent dry finish polishing, characterized in that the abrasive polishing with an aqueous solution of sodium thiosulfate is terminated by washing the treated product in a 30-40%solution of 2-methyl-2-aminopropane (CH3)3CNH2in ethanol With2H3HE.



 

Same patents:

FIELD: electronic industry.

SUBSTANCE: proposed method for producing photomask blanks involves two-stage polishing; first stage includes pre-polishing using perforated polishing canvas based on synthetic fibers, 8- 10 μm in diameters, at cubic density of 0.25 g/cm3; perforated holes are staggered; perforated-to-non-perforated area ratio being 0.08 0.09: 1, with ultrasonic action at frequency of 20 - 50 kHz for 30 - 50 minutes, temperature of 20 - 40 °C, and glass removal speed of 0.6 - 1.0 μm/min, whereupon glass removal is checked up and wafer is washed out in three-step ultrasonic line using surface active materials; during second stage wafer is subjected to finishing polishing by removing 10 - 12 μm of glass for 10- 15 minutes using softer polishing canvas.

EFFECT: enhanced surface quality of glass wafers for photomasks.

1 cl, 1 tbl

FIELD: production of pieces of electronics, applicable, for example, in operations of cleaning of semiconductor plates with the aid of brushes and mega sound.

SUBSTANCE: the device has loading and unloading holders, mechanisms of their vertical motion, mechanism for extraction of the plate from the holder, mechanism for loading of the machined plate in the holder, mechanism of horizontal motion of the plates, machining unit actuating the centrifuge installed in the process bath, brush. The mechanism of vertical motion of the unloading holder is installed at an angle to the horizontal plane in the direction of the plates feed, and the mechanism for extraction of the plates from the holder and the mechanism for loading of machined plates in the holder are made in the form of a suction cup with a vacuum table installed on a carriage for longitudinal motion, the suction cup of the mechanism for extraction of the plates from the holder is installed for turning on the carriage through a preset angle, the carriage is fastened at the same angle to the horizontal plane as the mechanism of vertical motion of the unloading holder, besides, the mechanism of horizontal motion of plates is made in the form of two manipulators for turning in the horizontal plane, each manipulator is provided with a carrier in the form of a ring with an inner tapered surface.

EFFECT: enhanced reliability of device operation and quality of machining, simplified construction.

2 cl, 9 dwg

FIELD: optoelectronics; producing wafers from ingots or bullions of monocrystals, such as sapphires.

SUBSTANCE: ingots or bullions are subjected to X-ray analysis to determine direction of cutting and at least one oriented flat is made thereon by grinding at its faces (0001). Then deviation from desired position is measured by means of diffraction meter and grinding process is repeated until deviation shorter than 3 minutes is attained. Cylinder blank is cut from monocrystal ingot or bullion perpendicular to at least one flat with distinct face on its surface. Then ends of cylinders are ground at 3-minute precision of their deviation from desired value. After that cylinder diameters are calibrated and base cut is made on each cylinder. Cylinders are annealed at 1300-1500 °C for minimum 8 hours. Upon cutting cylinder blanks into wafers annealing is repeated. Wafers are thinned by grinding and annealed under same conditions as cylinders.

EFFECT: ability of producing thin sapphire wafers at high precision with respect to diameter and thickness.

10 cl, 6 dwg

FIELD: electronic engineering; production of photomask blanks.

SUBSTANCE: proposed method for producing photomask blanks includes mechanical and chemical treatment of glass wafers, their placement in vacuum chamber, and coating with masking chromium layer by heating chromium-containing evaporator in nitrogen environment until desired optical density is attained, this being followed by wafer washing, covering with resist, and control. Chromium is cleaned prior to being applied to masking layer by remelting it at temperature of 2000 to 2100°C and residual pressure of 400 - 500 mm of mercury in argon environment; chamber is cooled down to room temperature, evaporator is heated at a rate of 500 - 700°C a minute to 1700 - 1850°C, exposed to this temperature for 25 - 35 minutes, then evaporator is heated to 1860 - 1950°C and chromium is evaporated at a rate of 140 - 160Å a minute until desired optical density is attained.

EFFECT: enhanced quality of varying-reflectance masking layer and environmental friendliness of method.

4 cl, 1 tbl

FIELD: treatment of semiconductor wafer surfaces, such as their chemical and mechanical polishing followed by washing them.

SUBSTANCE: proposed device has chemical-mechanical polishing mechanism, vertical displacement mechanism with magazine holder installed for step-by-step vertical displacement of magazines, robot-manipulator provided with wafer grip, two wafer transfer robots, and wafer washing plant. Magazine holder of vertical displacement mechanism is made in the form of hollow shaft mounted on top end of spline shaft for its turning through 360 deg. from drive; bottom end of hollow shaft mounts n magazine intake platforms, where 1 < n ≤ 4; axes of magazine intake platforms are spaced 90 deg. apart and bottom ends of intake platforms carry guides with slots similar to and coaxial with magazine slots. Magazine holder is installed in detergent tank; wafer grip of robot-manipulator is made in the form of removable ring whose top part is beveled to receive wafers and spring-loaded restricting pins. Wafer grip of robot-manipulator is provided with spray nozzles installed on top and below the ring.

EFFECT: reduced labor consumption for device manufacture due to its reduced size.

1 cl, 3 dwg

FIELD: machining semiconductor wafers.

SUBSTANCE: proposed machine tool designed for circular machining of semiconductor wafers to produce wafers having side surfaces of desired shape with minimal quantity of post-machining circular scratches and to execute great number of process operations without displacing wafers from one position to other has pair of supporting and driving rollers that function as supports for vertically disposed semiconductor wafers and are set in motion by means of drive belt connected to them. Machine tool also has two opposing movable wafer-machining units each incorporating first and second members designed for machining wafers when they are installed in first and second positions. Second design alternate of semiconductor wafer machine tool and self-aligning arbor fastening assembly is also proposed.

EFFECT: enlarged functional capabilities of machine tool, improved quality of post-machining side surfaces of wafers.

22 cl, 17 dwg

FIELD: thermochemical etching.

SUBSTANCE: method comprises etching the surface of articles made of high-melting chemically stable materials by applying the layer of an agent interacting the article material and heating the surface by laser pulse irradiating. The surface of the article is simultaneously affected by the laser pulses and vapors of a volatile composition, which is subjected to the pyrolytic decomposition to produce the above mentioned material. The amplitude of the laser pulse should be sufficient to cause the evaporation of the material.

EFFECT: enhanced adaptability to shaping.

3 cl

FIELD: semiconductor engineering; manufacture of extremely thin semiconductor structures and diaphragms.

SUBSTANCE: proposed method includes sticking of wafers and locking plates on faceplate using hold-down devices and separate mechanical treatment of plate and wafer surfaces to attain their desired definite thickness; faceplate is provided with at least two areas for sticking wafers and plates separated by blind slots; stuck to one of these areas are plates made of material whose hardness is greater than that of semiconductor wafer material; locking plates are mechanically finished and semiconductor wafers are stuck to free area of faceplate without changing position of pre-treated locking plates on faceplate. Adhesive used for sticking locking plates has melting point higher by at least 15 - 20 °C than that of adhesive employed for sticking semiconductor wafers. Locking plates are stuck using hold-down device independent of that used for semiconductor wafers.

EFFECT: enhanced quality and precision of treatment of semiconductor wafers.

3 cl, 4 dwg

The invention relates to semiconductor electronics and can be used in the production of semiconductor laser diodes and LEDs

The invention relates to the field of microelectronics, in particular, to a technology of manufacturing semiconductor structures, which is the element base microelectronics functional and can be used in the technology of integrated gas sensors with thin membranes /1 - 5 µm/ as well as membranes for x-ray masks

FIELD: optical engineering.

SUBSTANCE: method can be used for making lenses of leukosapphire and of other single-axis crystals for optical systems working within visible and IR spectral areas. Concave-convex blanks are made by plastic deformation of curve of flat-parallel plates from Z-cut of Al2O3 crystals. Plastic deformation of curve is made by means of chisel made in form of spherical segment. Entering surface of lens is formed by means of methods of rejection of excess layer of material out of blank as aspheric surface. Equation of axial cross-section of that aspheric surface looks like y=5,395 10-5x3+0,008x2+0,012x-0,023. Optical axis of lens is oriented along axis of symmetry of blank. Concave-convex lenses produced have minimal birefringence for convergent beams being transparent within 25000-2000 cm-1 area.

EFFECT: wider area of transparency.

2 dwg

FIELD: thin film physics, in particular, liquid films, surface tension of which is sensitive to their composition and to composition of surrounding environment.

SUBSTANCE: in accordance to method, for manufacturing sensitive cheap thin film evaporator-oscillators with new properties, liquid films are used made of common solutions with soap-like surfactants or chemically pure surfactants, but with special addition - noticeable proportion (1-50)% of component, that mixes well with water - dimethylsulfoxide - is additionally included in composition of soap solution for films.

EFFECT: expanded area of application of film evaporator-oscillators due to their creation on basis of new cheaper substances with high stability in broad range of temperatures.

2 dwg

Optical monocrystal // 2288489

FIELD: optical materials; monocrystals for visible and IR spectral ranges.

SUBSTANCE: optical monocrystals can be used for making IR-light guides used in laser engineering, IR fiber optics and non-linear optics, low-temperature pyrometry, IR-spectroscopy. Monocrystal on base of solid solution of AgCl-AgBr has additionally two impurities with like valences. One has to be cationic - single-valence thallium and the other one has to be anionic, like iodine. Monocrystal has argentums iodide of 0.5-1.5 mass % and iodide of single-valence thallium of 1.0-3.0 mass % at content of argentums chloride of 18.0-22.0 mass % and argentums bromide of 77.5-76.5 mass %. Due to presence of Agl and TLI optical monocrystal shows better physical and chemical properties.

EFFECT: widened transparency range; increased hardness and radiation resistance; stability to visible, UV, IR and X-ray radiation.

FIELD: optical engineering.

SUBSTANCE: plastic lens intended to absorb ultraviolet light with wavelength around 400 nm may be made from composition comprising (A) lens material monomer containing diethylene glycol bis(allyl) carbonate, (B) organic peroxide-based polymerization initiator, (C) cobalt compound selected from at least taw following: CoO-Al2O3 and CoO-Al2O4, and (D) at least one ultraviolet light-absorbing compound selected from 2-hydroxy-4-octyloxybenzophenone, 2,2',4,4'-terahydroxy-4-octyloxybenzophenone, and 2,2',4'-trihydroxy-4-octyloxybenzophenone. Invention also concerns lens manufacture method comprising: mixing compartment A, compartment B, fluid with cobalt containing compartment C with dispersant, and compartment D; pouring resulting mixed fluid into mold; and polymerization of the fluid in mold to form plastic lens.

EFFECT: improved quality of lens.

17 cl, 2 tbl, 9 ex

Optical member // 2282221

FIELD: optical devices with variable optical parameters, applicable in manufacture of miniature objective lenses with a variable focal length.

SUBSTANCE: the optical member has a container. The container comprises two transparent immiscible liquids with various indices of reflection. They are transparent in the area of operating wave-lengths. The first one is a dielectric. The second one features the properties of electric conduction. The liquids are engageable with each other with formation of an interface separating them. The interface curvature determines the optical parameters of the optical member. For control of the curvature of this interface the container is provided wits electrodes. A porous matrix with liquids with formation of an interface separating them is performed by impregnation.

EFFECT: developed a modification of an optical member with variable optical parameters using the effect of curvature of the interface formed on the boundary of engagement of two immiscible liquids with various indices of reflection, adapted to mass reproduction and featuring a stability to mechanical actions.

3 cl, 1 dwg

Optical member // 2282221

FIELD: optical devices with variable optical parameters, applicable in manufacture of miniature objective lenses with a variable focal length.

SUBSTANCE: the optical member has a container. The container comprises two transparent immiscible liquids with various indices of reflection. They are transparent in the area of operating wave-lengths. The first one is a dielectric. The second one features the properties of electric conduction. The liquids are engageable with each other with formation of an interface separating them. The interface curvature determines the optical parameters of the optical member. For control of the curvature of this interface the container is provided wits electrodes. A porous matrix with liquids with formation of an interface separating them is performed by impregnation.

EFFECT: developed a modification of an optical member with variable optical parameters using the effect of curvature of the interface formed on the boundary of engagement of two immiscible liquids with various indices of reflection, adapted to mass reproduction and featuring a stability to mechanical actions.

3 cl, 1 dwg

FIELD: optical materials.

SUBSTANCE: invention relates to radiation-sensitive compositions with variable refraction coefficients allowing novel model with refraction coefficient distribution to be obtained, in particular optical material used in optical electronics and information representation devices. Invention discloses emission-sensitive composition with variable dielectric permittivity containing decomposable compound (A), non-decomposable component (B) including inorganic oxide particles resistant to acid or base originated from acid or base source (C), and radiation-sensitive degradable substance (C), wherein refraction coefficient nA of decomposable compound A and refraction coefficient nB of non-decomposable compound B lie in one of following relationships: nB-nA ≥ 0.05 (1) and nA-nB ≥ 0.05 (2), amount of component B ranges from 10 to 90 wt parts based on 100 wt parts of summary amount of components A and B, and amount of component C ranges from 0.01 to 30 wt parts based on 100 wt parts of summary amount of components A and B. Model obtained from indicated composition allows one to vary in a simple way refraction coefficients thereby achieving sufficiently large difference between them and their stability irrespective of application conditions.

EFFECT: expanded possibilities in optical representation of information.

12 cl, 3 tbl, 7 ex

FIELD: optical materials.

SUBSTANCE: invention provides composition, whose refractory index can be varied by a simple way and which may manifest sufficiently large refractory index difference and provide stable refractory index configuration and optical material irrespective of conditions of their use and way of refractory index configuration and optical material formation. Composition, in particular, contains: (i) destructible compound, (ii) alcoholate hydrolyzate such as, for example, tetrabutoxytitanium, tetramethoxyzirconium, tetramethoxygermanium, or tetramethoxysilane, or halogen-containing compound such as tetrachlorosilane, and (iii) radiation-sensitive destructor.

EFFECT: achieved preparation of stable refractory index varying optical materials.

12 cl, 2 tbl, 4 ex

FIELD: special-destination substances.

SUBSTANCE: invention provides emission-sensitive composition containing polymerizable compound A, non-polymerizable compound B having lower refractory index than polymer of polymerizable compound A, and emission-sensitive polymerization initiator C. Invention also provides method for varying refractory index, structure formation method, and optical material preparation method.

EFFECT: stabilized structure and optical material independent of application conditions.

6 cl, 1 tbl, 12 ex

FIELD: ophthalmology.

SUBSTANCE: process of making plastic lens related to techniques used for making lenses which can be applied in ophthalmology and optical engineering. Plastic lens proposed is capable if absorbing UV radiation. Lens has light yellow color. Plastic lens has plastic substrate based on derivation of benzophenone which is presented by formula I given in the description, where R is linear or branched alkyl group having 2 to 12 atoms of carbon or alkoxyl group having 2 to 12 atoms of carbon.

EFFECT: improved absorption.

11 cl, 11 dwg

The invention relates to a method of hydrothermal etching, providing for the establishment of environmentally friendly methods of etching of single crystals of lithium tantalate, used in electronic engineering
Up!