Method for making evaporated reagents for chemical deposition of vapours
Abstract
Vaporized reactants, useful for chemical vapor deposition of a coating on the surface of a hot substrate, are prepared by initially heating a liquid coating precursor, injecting the liquid coating precursor into a vaporization chamber, simultaneously admitting a blend gas into the vaporization chamber, heating the liquid and blend gas to cause the liquid to vaporize at a temperature below its standard vaporization temperature, and thoroughly mixing the coating precursor vapor and blend gas, to produce a stream of vaporized reactant for pyrolytic decomposition at the surface of the hot substrate. A horizontal thin film evaporator provides a particularly suitable vaporization chamber for the present process.

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Expired 17 October 2005, 20.9 years ago.
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23 claims: 17 independent, 6 dependent
- 1A method of producing vaporized chemical vapor deposition reagents which comprises providing a coating precursor at a temperature above its melting point but well below its standard evaporation temperature whereby the coating precursor is in the form of a liquid, characterized in that A) is simultaneously and continuously carried out the steps of i) injecting a liquid coating precursor into a vaporization chamber defined in part by at least one circumferential wall, wherein the liquid coating precursor produces vapors, ii) supplying the vaporization chamber of the gaseous mixture in an amount sufficient to increase the mass transfer of the coating precursor vapors and thereby induce accelerated vaporization of the liquid coating precursor;comprising separating the liquid precursor as a thin film along the wall of the chamber, whereby the liquid coating precursor evaporates completely at a temperature below its standard evaporation temperature, yielding a vaporized precursor stream having a high and uniform precursor concentration;and B) the reaction gas stream is transferred out of the vaporization chamber. 1. Sposób wytwarzania odparowanych reagentów do chemicznego osadzania par obejmujący dostarczenie prekursora powłoki w temperaturze wyższej od jego temperatury topnienia, ale znacznie niższej od jego standardowej temperatury odparowywania, dzięki czemu prekursor powłoki jest w postaci cieczy, znamienny tym, że A)jednocześnie i w sposób ciągły przeprowadza się etapy i) wtryskiwania ciekłego prekursora powłoki do komory odparowywania, określonej w części co najmniej jedną ścianą obwodową, w której ciekły prekursor powłoki wytwarza pary, ii) doprowadzenia do komory odparowywania mieszanki gazowej w ilości wystarczającej do podwyższenia przenoszenia masy par prekursora powłoki i w ten sposób wywołania, przyspieszonego odparowania ciekłego prekursora powłoki, iii) mieszania ciekłego prekursora powłoki, par prekursora powłoki i mieszanki gazowej, obejmującego rozdzielanie ciekłego prekursora jako cienkiego filmu wzdłuż ściany komory, dzięki czemu ciekły prekursor powłoki odparowuje całkowicie w temperaturze poniżej jego standardowej temperatury parowania, dając strumień odparowanego prekursora mający wysokie i równomierne stężenie prekursora i B) przenosi się strumień gazu reakcyjnego poza komorę odparowywania.
- 5The method according to p. The process of any of the preceding claims, wherein the gas mixture is heated to approximately the temperature of the vaporization chamber prior to injection of the gas mixture into the chamber. 5. Sposób według zastrz. 1, albo 2, albo 3, albo 4, znamienny tym, że mieszankę gazową ogrzewa się w przybliżeniu do temperatury komory odparowywania przed wtryśnięciem tej mieszanki do komory.
- 8A method of producing vaporized reactants which comprises providing the coating precursor at a temperature above its melting point but significantly below its standard evaporation temperature whereby the coating precursor is in the form of a liquid, characterized in that A) the steps of i) injecting are performed simultaneously and continuously. a liquid coating precursor to the vaporization chamber, where the liquid coating precursor produces steam, ii) supplying an amount of gaseous mixture to the vaporization chamber sufficient to increase the mass transfer of the coating precursor vapors, thereby causing accelerated evaporation of the liquid coating precursor;and evaporated at a temperature below its standard evaporating temperature, wherein a vaporized gaseous reactant stream having a high, uniform concentration of coating precursor is obtained, B) transferring the gaseous reactant stream out of the evaporation chamber and C) contacting the gaseous reactant stream with a liquid glass substrate maintained at a temperature of at least 399 ° C. 8. Sposób wytwarzania odparowywanych reagentów obejmujący dostarczenie prekursora powłoki w temperaturze wyższej od jego temperatury topniena, ale znacznie niższej od jego standardowej temperatury odparowywania, dzięki czemu prekursor powłoki jest w postaci cieczy, znamienny tym, że A)jednocześnie i w sposób ciągły przeprowadza się etapy i) wtryskiwania ciekłego prekursora powłoki do komory odparowywania, w której ciekły prekursor powłoki daje parę, ii) doprowadzania do komory odparowywania mieszanki gazowej w ilości odpowiedniej do zwiększenia przenoszenia masy par prekursora powłoki, powodując w ten sposób przyspieszone parowanie ciekłego prekursora powłoki i iii) mieszania ciekłego prekursora powłoki, par prekursora i mieszanki gazowej, na skutek czego ciekły prekursor powłoki zostaje całkowicie odparowany w temperaturze niższej od jego standardowej temperatury parowania, przy czym otrzymuje się strumień odparowanego reagenta gazowego mającego wysokie, jednorodne stężenie prekursora powłoki, B) przenosi się strumień gazowego reagenta poza komorę odparowywania i C) kontaktuje się strumień reagenta gazowego z podłożem z płynnego szkła utrzymywanym w temperaturze co najmniej 399°C. 167 110 167 110
- 10b the way according to ensiss. 9, an enormous and the fact that a body is applied in a blue-greening poeiome from a thin film. 10. bposób według ensiss. 9, ennmienny iym, że siosuje się komo^ wdpnzwpywnnin sinnowiącą poeiome odpnzowewncz cienkiego filmu.
- 11b the way according to ensise. 8, n or 9, n or 10, ennchangeable that a continuous secret tape is used as the substrate for the liquid secret. 11. bposób według ensise. 8, nlbo 9, nlbo 10, ennmienne iem, że jako podłoże e płynnego sekłn siosuje się ciągłą inśmę seklnną.
- 12b the way according to ensise. 11, ennmienne iym that the sengcntn gas stream is connected to the substrate, podcsws when inśmn jesi podiseymywann pseee bathing ee molten meinl and jesi in tempcsntussc enpnriej in the ene ranging from about 593 ° C to about 732 ° C. 12. bposób według ensise. 11, ennmienne iym, że sisumień gzowego sengcntn koninkiuje się e podłożem, podcsws gdy inśmn jesi podiseymywann pseee kąpiel ee stopionego meinlu i jesi w tempcsntussc enpnriej w en^esie od około 593°C do około 732°C.
- 13b the way according to ensise. 8, n or 9, n or 10, n or 12, ennormical and so that the sengenin g8eowcgw is connected to the substrate in the presence of ilene. 13. bposób według ensise. 8, nlbo 9, nlbo 10, nlbo 12, ennmienne iym, że sisumień sengenin g8eowcgw koninkiuje się e podłożem w obecności ilenu.
- 14b the way according to ens ^ e. 8, nbbo 9, nbbo 10, nbbo 12, ennmienne iym that the psekussos of the shell is cut out with a group consisting of diphtheria, diphthalmia, quadripolar ceteswchlwsek ieinnu, cetesoieopswpnnolnn ieinnu, tsójetelcumin, diethylaluminum chloride, aluminum trimethyl, aluminum nceteloacetoninn, aluminum acetate, diwsilnnnn, meteloisojcioksysilnn, nceielonceioninn cenku, pzopiwninnum cenku and their muscles. 14. bposób według ens^e. 8, nlbo 9, nlbo 10, nlbo 12, ennmienne iym, że siosuje się psekussos powłoki wybsany s grapy obejmującej dwucEjosek dwumeielocene, czterwetwksysilnn, dwu^losek dwueielocene, dwuocinn dwubuielocene, ceiesomeielocenę, izójchlwsek meiylocyny, cMosek isójeielocene, chlosek isójmeielwceny, ieinninn cetesobnielu, ceteswchlwsek ieinnu, cetesoieopswpnnolnn ieinnu, tsójetelwglin, chlosek dwuetyloglinu, trójmctyloglin, nceteloacetoninn glinu, octan glinu, dwueiylwdwuchlwswsilnn, meteloisójcioksysilnn, nceielonceioninn cenku, pzopiwninn cenku i ich miesenniny.
- 15b the way according to ensise. 14, ennmional iem that the shell pserussws apply to dimethyltin. 15. bposób według ensise. 14, ennmienne iem, że jnko pserussws powłoki siosuje się dwuchlosek dwumeiylocyne.
- 16b the way according to ensise. 14, ennmionny iym that 95% of the dimettelocin dichlide and 5% of the fresh mciyltin isocide is used in the shell. 16. bposób według ensise. 14, ennmionny iym, że jnko pzekussws powłoki siosuje się 95% wngowych dwu^losku dwumttelocyny i 5% wnaowych izójchlozku mciylocyny.
- 17b the way according to ensi ^. 8, energy, and the fact that helium, neoi, hydro, nsgon and their muscles are used. 17. bposób według ensi^. 8, ennmienny iym, że jnko m^enn^ gneową siosuje się hel, neoi, wodós, nsgon i ich miesenniny.
- 18b the way according to ensise. 8, in which the coating liquid is injected into the drainage chamber at a low temperature of about 21 ° C to about 277 ° C. 18. bposób według ensise. 8, ennoienny iym, że ciekły pzekuzsws powłoki wtryskuje się do komory odpni^owywnnin w iempesniusee enwasiej w znkzesie od około 21°C do około 277°C.
- 19b the way according to ensise. 8, ennmantial, that the liquid psekur'sws of the shell, the stripes of the crust of the shell, and the glandular mucosa of the lining of the shell from about 35 ° C to about 290 ° C. 19. bposób według ensise. 8, ennmienny iym, że ciekły psekur'sws powłoki, pasy pzckuzsozn powłoki i miesennkę gneową wgseewn się w komosee wdpnswwewnnin do iempczniury od około 35°C do około 290°C.
- 20bposób według ensise. 8, ennmienny iym, że ciekły psekussos powłoki wisyskuje się do komosy wdpnswwywnnin s seybkością od około 0,2268 kg do około 54,43 kg nn godeinę. twenty. b the way according to ensise. 8, that the liquid psekussos of the shell is suspended in the quinoa at a rate of from about 0.2268 kg to about 54.43 kg bn godeine.
- 21b the way according to ensise. 8, it is known that the head muscle is fed back to the moth at a pressure ranging from about 13.73 kPn to about 102.96 kPn. 21. bposób według ensise. 8, snnmicnny iym, że miesennkę gneową dwpsowndzn się do komose wdpnzowywnmn pod ciśnieniem od około 13,73 kPn do około 102,96 kPn.
- 22b the way according to ensi ^. 8, snnmicnny Iym, that the mics of the gnead dopswwnden up to the speed of the quota is from about 100 to about 400 standard lks nn a minute. 22. bposób według ensi^. 8, snnmicnny Iym, że micssnnkę gneową dopswwnden się do komose wdpnzowywnnin s seybkością od około 100 do około 400 standardowych lksów nn minuię.
- 23b the way by swsiss. 8, changeable and that the snippet of gingiva is applied to the wissymnnin of the nn shell with the sskle of the pssy growth rate of up to about 2200 A nn a second. 23. bposób według swsiss. 8, snnmienny iym, że sisumień odpnswwnncao zcngenin gzowego siosuje się do wissymnnin powłoki nn gosącym sskle pssy ssybkości wzrostu do około 2200 A nn sekundę.
Independent claims17
47 paragraphs, as filed
Pseedmioiem wynlneku jesi the way of gassing sengents to chcmicencaw osndennin pns, n more precisely the way of triggering the meat of the nineteen sengenin, e.g. psekussosn shell, and gnew muscles used pseynly chemicsnym osndsnin osndsnin.
The products that have ever been created have been created by the continuous pwplernnin of the subsoil of the subtle podcens in the enormous success of the "liquid psoces of the Seklnssritgw". b the way it includes a foundry bath of molten tin, a bath of melted tin, a pair of properly connected ones, nnoply pssenie sskłw, after appropriate ingestion, nn salt in ^ i ^ and ^ and gagging, probing in the bathing line and sucking in the cooling of the psyche into the minsine , pwcsąikwww in odpsężnska iunelwpej, in n8sitpnie psees issue of nn dsi8łnnie iemperniuse oivczenin. In the liquid part of the psoccsu, the non-lubricating nymph is emitted, which makes it possible to externally develop
167 110 contact with a molten tin bath to prevent oxidation. The air atmosphere is maintained in the lehr. Chemical vapor deposition of the various coatings may conveniently be carried out in the bath or lehr or even in a transfer zone therebetween.
The physical form of the reactants used in glass coating processes is typically a gas, liquid, solid, evaporated liquid or solid, liquid or solid dispersed in the carrier gas mixture, or evaporated liquid or solid dispersed in the carrier gas mixture. The method of chemical vapor deposition typically involves the use of a vaporized liquid or solid, which is generally dispersed in the carrier gas mixture.
Chemical vapor deposition methods are well known in the art of coating glass substrates. From US patent specification Eat. No. 4,1 (00330), a method of coating a glass substrate with a first silicon layer and a second metal oxide layer deposited by pyrolytic decomposition of a metal coating compound that occurs on the surface of a hot substrate in an oxidizing atmosphere is known.
From US patent specification US No. 4,847,157, a method of coating a glass substrate with a first silicon-containing layer, an overlying layer containing titanium nitride and a second silicon-containing layer covering the titanium nitride-containing layer and optionally an abrasion-resistant layer, e.g. containing silicon.
From US patent specification US No. 4,692,180 discloses a method of sputtering a powdered metal compound directly onto the surface of hot glass strips produced by a glass melting process, the metal oxide coating being obtained by pyrolytic decomposition of the powder. From US patent specification US No. 3,852,098 discloses a method of vaporizing dispersed, powdered metal compounds with a hot carrier gas which is then directed to the surface of a hot glass substrate to deposit a metal oxide coating thereon. Similarly, according to US Patent No. US No. 2,780,553, a solid metal compound is used, in which case the solid bed of the coating metal compound is evaporated by contacting it with a hot carrier gas. Finally, from U.S. Patent No. US No. 4,351,861 discloses a method for fluidizing reagent particles in a carrier gas which is in turn heated to vaporize the suspended particles and then direct the resulting vapors to the surface of a hot glass substrate to form a coating.
Known processes using solid coating precursor particles result in reactant streams that are influenced by many variables such as fluctuation in particle size, variations in particle surface area over time, as well as difficulties in conveying solids at the same speed, etc.
There are also known processes in which organometallic salts are dissolved in an acid or in a hydrocarbon and then the resulting solution is evaporated in a hot carrier gas. From US patent specification US No. 4,571,350, a method of spraying a dispersed mist of a solution of a metal salt into a smoke chamber is known. The solution evaporates and then reaches the surface of the hot glass substrate. From US patent specification US In US 3,970,037, it is known to dissolve a coating reagent in a solvent, then spray the resulting solution in a hot carrier gas where it is vaporized and direct the resulting stream to the surface of a hot glass substrate. In both cases, the reagent pyrolytically decomposes to form an oxide coating, however, the dissolving agents interfere with the molecular transport on the glass surface, resulting in deformation of the deposition.
Yet another method of producing thermally decomposable metal vapor streams for chemical deposition processes is to pass hot carrier gas bubbles through a metal salt in a molten state as disclosed in US Pat. US Nos. 4,212,663 and 4,261,722.
From US patent specification US No. 3,808,035, a process is known to pass a stream of inert gas through a bubbler to obtain a gas stream with a low concentration of precursor, and then direct this gas to the substrate at a temperature of 100-300 ° C. While the bubbling process allows the liquid containing the precursors to evaporate directly into an inert gas, it has many disadvantages that reduce
16 * 7 110 is useful for making vaporized chemical vapor deposition reagents. First, the liquid coating precursor must be kept at about the vaporization temperature throughout the process in order to ensure a high concentration of the vaporized reactant in the carrier gas. This elevated temperature, maintained over an extended period of time, can accelerate the decomposition of coating precursors, some of which are very sensitive to heat. In addition, the specific heat of vaporization required to convert the liquid to vapor causes the temperature of the liquid to drop as the carrier gas bubbles are passed through. A drop in liquid temperature, which is difficult to evenly correct using external heat sources, causes a drop in vapor pressure above the liquid which in turn causes a steady decrease in the concentration of vaporized precursor in the carrier gas stream. Finally, in a bubble bubbling process in which the liquid bath contains two or more coating precursors having different vapor pressures for each of the pure components, the more volatile component will preferentially evaporate, thereby changing the partial vapor pressure relative to the proportion of the respective component in the liquid. and thus the concentrations of the vaporized reactants in the carrier gas stream will change as the liquid bath is depleted.
It should be noted that the prior art described above was collected and tested only in the light of the method of the invention. It cannot, however, be inferred that such a diverse description of the state of the art would have been made without the motivation of the present invention.
It would be desirable to be able to vaporize coating precursors, or mixtures of such precursors, so as to obtain a uniform, steady stream of concentrated coating precursor vapor, which would allow the formation of thicker deposits than those that could be obtained by conventional methods, while maintaining better control of the coating being deposited.
The invention relates to a process for the preparation of vaporized reactants, used, for example, in the chemical deposition of vapors on hot substrates. In accordance with the invention, it has surprisingly been found that vaporized reactants can be produced from the coating precursors by a new process that allows for the evaporation of higher, solid concentrations of the reactants in a gaseous stream, the process of providing the coating precursor at a temperature above its melting point but substantially below its melting point. standard evaporation temperature, so that the coating precursor is in the form of a liquid, wherein the process is carried out characterized in that A) the steps of i) injecting a liquid coating precursor into a vaporization chamber defined in part by at least one circumferential wall are carried out simultaneously and continuously, in which the liquid coating precursor generates vapors, ii) supplying an amount of gaseous mixture to the vaporization chamber sufficient to increase the vapor mass transfer of the coating precursor and thus induce accelerated evaporation of the coating precursor liquid; chamber walls, whereby the liquid coating precursor evaporates completely at a temperature below its standard evaporation temperature, giving a vaporized precursor gaseous stream having a high, uniform concentration of the coating precursor; and B) transporting the mixture of coating precursor vapors and gas mixture out of the evaporation chamber.
The horizontal thin film vaporizer is a suitable vaporization chamber in the process of the invention. Preferably, the liquid coating precursor is injected through the upper inlet and the gas mixture is delivered through the lower thin film horizontal evaporation inlet. The gas mixture is preferably preheated to a temperature approximately to which the vaporization chamber is heated. The evaporation chamber is preferably heated to a temperature higher than the temperature of the liquid precursor injected into the chamber but lower than the standard evaporation temperature of the coating precursor.
The process of the invention is suitably carried out as a continuous process and is suitable for the evaporation of precursors of coating reagents for use in chemical vapor deposition. It is especially suitable for the chemical vapor deposition of coatings on glass produced in a liquid glass process. In the latter case, the process comprises supplying the coating precursor at a temperature above its melting point but
167 110 substantially lower than its standard evaporation temperature, whereby the coating precursor is made to be in the form of a liquid, characterized in that A) the steps of i) injecting the liquid coating precursor into the vaporization chamber are carried out simultaneously and continuously. the coating precursor produces steam, ii) feeding the gaseous mixture into the vaporization chamber in an amount sufficient to increase the weight transfer of the coating precursor vapors, thereby causing accelerated evaporation of the liquid coating precursor; and iii) mixing of the liquid coating precursor, the coating precursor vapor and the gas mixture, whereby the liquid coating precursor is completely vaporized at a temperature below its standard evaporation temperature, yielding a vaporized gaseous reactant stream. having a high homogeneous concentration of the coating precursor, B) transferring the mixture of coating precursor vapors and gas mixture out of the evaporation chamber; and C) contacting the mixture with a liquid glass substrate maintained at a temperature of at least 399 ° C.
In the accompanying drawings, Fig. 1 is a somewhat schematic illustration of an apparatus for carrying out the method of the invention, showing a vertical section of a vaporization chamber, in this case a horizontal thin film vaporizer, and FIG. 2 is a vertical section of the vaporization chamber along line 2-. 2 in Fig. 1.
With reference to the more detailed drawings discussed, the apparatus for carrying out the process of the present invention comprises a preheating vessel 10, equipment generally designated 11 for introducing a gas mixture into the system, and a vaporization chamber generally designated 12. The vaporization chamber 12 has a liquid zone. 13 and a vapor zone 14. The boundary area between these two zones is generally represented by line 15 in Fig. 1. The liquid zone 13 is defined as the area within the evaporation chamber 12 in which the wall 16 of the chamber 12 is covered with the liquid coating precursor, and the vapor zone 14 is defined as the area within the evaporation chamber 12 where the coating precursor has been fully vaporized. The location of the boundary (indicated by line 15) between the liquid zone 13 and the vapor zone 14 will depend on the volatility of the particular coating precursor that is vaporizing, the temperature of the steam chamber enclosure, the mass flow rate of the blend gas, etc. Thus, as long as a coating precursor having a relatively high volatility is used the vaporization chamber will have a relatively large vapor zone 14.
The liquid coating precursor is injected into the liquid zone 13 of the evaporation chamber 12 through the upper inlet 17, which is so-called because it is located adjacent to the top of the evaporation chamber 12. The gaseous mixture is injected into the liquid zone 13 of the evaporation chamber 12 through the lower inlet 18, so-called because it is located adjacent the bottom of the evaporation chamber 12. The gas mixture, which may for example consist of helium or nitrogen or mixtures thereof, is stored in cylinders 19 and 20 and is fed through regulators 21, flow meters 22 and valves 23 to the inlet 18. As the gas mixture is injected downwards and the precursor the coating is injected from the top, direct contact occurs between the falling liquid and the rising gas mixture.
As shown in Figures 1 and 2, mixing blades 24 rotate inside the evaporation chamber, which spreads the liquid precursor as a uniform, thin film over the wall or walls of the evaporation chamber and further mixes the coating precursor with the gas mixture. As soon as the coating precursor is converted to vapor, it is discharged together with the gas mixture from the vapor zone 14 through the outlet 25. The steam can then be further treated, for example continuously, with other steam reactants or dopants, and / or transported to a depositionable region (CVD).
The coatings may be deposited on the surface of the hot glass substrate in a manner generally known in the art as chemical vapor deposition (CVD)]. The process is typically carried out during the manufacture of glass in a fluid manufacturing process and may take place in a molten metal bath in which the glass strip typically has a temperature in the range of about 593 ° C to about 732 ° C, lehr (glass temperatures from about 399 ° C). to about 566 ° C) or in the transfer zone between the bath and the lehr (glass temperatures from about 551.5 ° C to about 593 ° C). Coating precursors are evaporated and transferred to a location on or near the surface of the advancing glass ribbon. Coating precursors in the presence of oxygen
167 110 decompose pyrolytically to give an oxide coating on the glass surface. However, the method of the invention is not limited to the deposition of oxide coatings, and can also be used to deposit non-oxide coatings such as silicon or titanium nitride. In addition, the method of the invention can be used for chemical vapor deposition on any substrate and is not limited to glass deposition.
Suitable deposition precursors useful in practicing the process of the invention include, but are not limited to, dimethyltin dichloride, tetraethoxysilane, diethyltin dichloride, dibutyltin diacetate, tetramethyltin, methyltin chloride, triethylmethyltinylchloride, titaniletetyl chloride, tetramethyltartylchloride, titanium chloride. titanium, triethylaluminum, diethylaluminium chloride, aluminum trimethylacetonate, aluminum acetylacetonate, aluminum acetate, diethyl dichlorosilane, methyltriethoxysilane, zinc acetylacetonate, zinc propionate or mixtures thereof. These compounds are generally well known in CVD technology as hot glass coating precursors. The process of the invention may well be performed with any precursor material or mixtures thereof which affect the vapor pressure. A preferred coating precursor for depositing tin oxide is dimethyltin dichloride or a mixture of dimethyltin dichloride and methyltin trichloride, for example 95% by weight dimethyltin dichloride and 5% by weight methyltin trichloride.
The coating precursors used in the process of the invention are either liquids which have a vapor pressure at room temperature or solids which, when heated to above room temperature but below their standard evaporation temperatures, become vapor pressure liquids at these elevated temperatures. By the term "standard evaporation temperature as used in the text, is meant the temperature at which the vapor pressure of the pure liquid component is equal to 1 atmosphere (0.98 × 10<sup>2</sup> kPa). In any event, the coating precursors used in the process of the invention are initially heated in the preheating vessel 10 to temperatures above their melting points, but well below their standard evaporation temperatures. At these temperatures, the coating precursors become volatile liquids that are well below their decomposition temperatures. The term "well below standard evaporation temperature as used herein means a temperature that is 6 to 50 ° C below the standard evaporation temperature of the compound (coating precursor), so that the thermal decomposition of heat sensitive compounds is greatly reduced.
Adding the gas mixture to the vapor chamber increases the mass transfer of the coating precursor vapors from the vaporization chamber. This increase in vapor mass transfer of the coating precursor causes accelerated evaporation of the liquid coating precursor. The contacting of the liquid coating precursor and the gas mixture preferably occurs in a vaporization chamber. By the term "evaporation chamber" as used herein is meant a closed vessel containing a liquid zone and a vapor zone into which the liquid injected into the vessel is thrown against its inner wall to form an even thin film thereon, and then evaporated. The force with which the liquid is thrown against the wall can be imparted, for example, by mechanical impellers, the forces of the liquid flow due to pressure or the centrifugal force from the vanes rotating inside the vaporizer, or the rotating vaporizer housing (with or without blades), etc. The vessel walls can optionally be heated to increase the rate of vaporization of the liquid as it contacts the walls of the vaporization chamber. These gas mixtures include, for example, helium, nitrogen, hydrogen, argon, or any other gaseous carrier that is chemically inert to the coating precursor at the temperatures used, as well as mixtures thereof. Preferred gas mixtures are helium and nitrogen and mixtures thereof.
The coating precursor may be preheated in any known apparatus used to heat solids or liquids, such as a fired or electrically heated preheat vessel containing the coating precursor. This precursor is usually heated to a temperature above its melting point but well below the standard evaporation temperature and then injected as a liquid into the evaporation chamber.
In the vaporization chamber 12, the liquid coating precursor is completely vaporized. The rotating blades of the agitator 24 are used to mix the contents of the evaporation chamber 12. Due to the centrifugal forces caused by the movement of the mixing blades 24, the liquid
167 110, the coating precursor is continuously distributed as a thin, uniform film on the wall of the evaporation chamber 12. The film flows towards the outlet 25 imparting turbulence, causing it to become turbulent at a high rate of heat transfer to the liquid film, accompanied by vapor formation. In addition, the liquid coating precursor, the coating precursor vapors and the gas mixture are heated inside the evaporation chamber 12 to a temperature higher than the temperature of the injected liquid coating precursor but still lower than the standard evaporation temperature of the coating precursor. The temperature to which the ingredients are heated will be determined by the thermal decomposition characteristics of the particular coating precursor in use and the mass transfer rate of the selected blend gas. The liquid coating precursor and the chemical composition of the gas mixture as well as their respective amounts introduced into the vaporization chamber 12 must be correctly selected so that there is a sufficient amount of the gas mixture to cause an increase in mass transfer of the vaporized coating precursor, thereby accelerating the evaporation of the liquid. In this way, the liquid coating precursor is completely vaporized at a temperature below the standard vaporization temperature.
Since the liquid coating precursor is rapidly evaporated in relatively small amounts, larger masses of liquid encounter elevated temperatures for only a short time. This is the difference and the opposite of the known gas bubble process which requires the entire bath to be kept at a temperature close to its vaporization temperature, often leading to decomposition of the liquid coating precursor. Since in the process of the invention most of the liquid is kept lower than the temperature of known processes, the decomposition of the liquid coating precursor is minimized.
The liquid coating precursor, the coating precursor vapors, and the gas mixture are heated conveniently by heating the evaporation chamber 12 using known means, such as, for example, an electrically fired or heated, or steam jacket. In this way, the temperature of the evaporation chamber 12 is kept constantly and the heat required for evaporation is supplied. The coating precursor may be preheated in the preheating vessel 10 to a temperature above its melting point, but well below its evaporation temperature. The gas mixture is preferably preheated to about the temperature of the vaporization chamber before it is introduced into the chamber.
The evaporation chamber 12 is provided with means to ensure complete mixing of the precursor with the gas mixture, whereby a completely homogeneous mixture of the reagent is directed to the substrate.
The process of the invention provides an improved method of evaporating coating compounds which produces a homogeneous, highly concentrated, vaporized coating precursor and gas mixture. This is advantageous in accurately controlling the thickness of the coating applied, reducing the amount of decomposition coating precursor prior to application to the glass, and allows for the production of thicker coatings than could be obtained by known evaporation processes.
A horizontal thin film vaporizer such as, for example, commercially available from Artisan Industries, Inc., Waltham, Massachusetts, St. US Of America, having the commercial designation "One-Half Square Foot Rototherm E", is a suitable evaporation chamber 12 for the process of the invention. Preferably, the liquid coating precursor is injected into the vaporization chamber 12 through the upper inlet 17, and the gas mixture is injected into the vaporization chamber 12 through the lower inlet 18 which is located at the same end of the vaporization chamber 12 as the higher inlet 17. Additionally, rotation of the assembly is the paddles 24 inside the evaporation chamber 12 (in this case, a horizontal film vaporizer) cause the coating precursor and gas mixture to mix thoroughly. The motor 26 drives the rotating blades 24. Conveniently, the vapor mixture is exhausted through an outlet 25 which is located at the opposite end to that of the upper and lower inlets 17 and 18.
The process of the invention is operated continuously, so that a gas mixture stream is produced continuously and has a uniform, high concentration of coating precursor vapors. The stream is directed from the vaporization chamber 12 through the conduit to the surface of the hot substrate by the pressure generated by the vaporization of the liquid injected through the upper inlet 17 and by introducing a pressurized gas mixture through the lower inlet 18 into the vaporization chamber 12.
167 110
If the coating precursors and gas mixtures discussed herein are used in the process of the present invention, the gas mixture is typically fed through the lower inlet 18 to the vaporization chamber 12 at a pressure of about 13.73 kPa to about 102.96 kPa and a flow rate of about 100 to approximately 400 standard liters per minute. The liquid coating precursor is preheated to a temperature of from about 21 ° C to about 277 ° C and then injected into the vaporization chamber through the upper inlet 17, with the vaporization chamber 12 at a temperature of about 35 ° C to about 290. ° C. The liquid coating precursor preferably evaporates at a rate of from about 0.2268 kg to about 54.43 kg per hour. The mass flow rates of the gaseous mixture and the liquid coating precursor mentioned above are those recommended when, for example, a horizontal thin film vaporizer is used as the vaporizer chamber 12. However, it should be understood that any flow rate of the mixture gas and liquid coating precursor may of course be used, with a given appropriate evaporation chamber and reaction conditions. For example, larger RotothermE models will vaporize larger amounts of the liquid coating precursor. These rates will be determined by the required coating thickness and rate of growth.
For example, a reactive vapor mixture suitable for chemically vapor deposition of a tin oxide coating can be prepared using dimethyltin dichloride as a precursor. Typically, the nitrogen gas mixture is fed through the lower inlet 18 to the evaporation chamber 12 at a pressure of about 13.73 kPa to about 102.96 kPa and a flow rate of about 100 to about 400 standard liters per minute. Dimethyltin dichloride is first preheated to a temperature of about 107 ° C to about 190.5 ° C, then injected, e.g. as a pressurized liquid stream or pumped into the evaporation chamber, while keeping the contents of the evaporation chamber 12 at a temperature. from about 101 ° C to about 204 ° C. The liquid dimethyltin dichloride coating precursor preferably evaporates at a rate of from about 0.45 kg to about 290.3 kg per hour or 0.77 to 49 standard liters per minute. Dimethyltin dichloride flow rates such as these, together with a gas mixture rate of 400 standard liters per minute, will result in a reactant vapor stream at the outlet with a content of 0.19% to 12.3% of dimethyltin dichloride gas phase (v / v). As the gas mixture flows more or less, the percentage of the gas phase will increase or decrease, respectively. The above-mentioned mass flow rates of the mixture of gaseous and liquid coating precursor are the proposed rates, if, for example, a 12 horizontal vaporizer with a thin film film with a surface area of 0.1493 m is used as an evaporation chamber.<sup>2</sup>. Tin oxide coatings may be deposited on glass at a growth rate of up to about 2200 A per second using dimethyl tin dichloride mixtures within the proportions given above.
Most of the coating precursors after evaporation are extremely flammable under oxidative conditions and therefore can only be transferred to the reaction site in a carrier gas stream at a concentration of a few percent of the gas phase. Among the vapor concentrations of the coating precursor, they will ignite upon contact with the hot substrate surface in an oxidizing atmosphere. Therefore, the coating operation must be carried out with a vaporized coating precursor stream having a concentration below the flammability limit for that particular coating precursor.
Due to the inherent variability of known evaporation processes, e.g. evaporation of dispersed or fluidized powders, evaporation of particles in a packed bed, evaporation of dissolved compounds, or bubbling of a carrier gas through the liquid metal salt, the concentrations of coating precursor vapor in the carrier gas produced by such processes usually vary. or change over time. Therefore, the average useful concentration of the coating precursor vapors must be well below the flammability limit, so that a concentration ripple will not ignite the coating precursor vapors.
Conversely, the process of the invention produces a steady stream of coating precursor vapor having a uniform concentration. As there are fewer variations in the concentration of the vapor stream, it can be transported closer to the flammability limit. As a result, more of the coating precursor can be evaporated and transferred to the reaction zone, thus allowing thicker coatings and higher growth rates to be obtained than could be obtained by evaporation processes known heretofore.
16*7 110
It is necessary to recognize that the process conditions are not sharp in order to favorably carry out the process of producing the vaporized reactants according to the present invention. The process conditions described above are generally disclosed in terms known to the practice of the invention. Occasionally, however, the described process conditions may not be strictly applicable to each compound falling within the scope of the disclosed invention. Those compounds concerned will be readily recognized by those skilled in the art. In such cases, the process may be carried out advantageously by making the usual modifications known to those skilled in the art, e.g. increasing or lowering the temperature conditions, changing the rate of introduction of the coating or gas blend precursor, changing possible CVD reagents or phases in the blend, routine modification of the evaporation process conditions, etc.
The invention will be more readily understood by reference to a specific embodiment that will be representative of it. However, it should be taken into account that the particular case is presented by way of illustration only and that the invention may be practiced other than as specifically illustrated without departing from its spirit and scope. For example, a device other than a horizontal film thin film vaporizer, but capable of tight contact, quick heating, and thorough mixing of the coating metal compound and gas mixture, may also be used as the vaporization chamber.
An example. Dimethyltin dichloride was heated to a temperature of about 138 ° C and injected as liquid at a rate of about 290 kg per hour into the upper inlet 17 of the vaporizer chamber 12, in this case a horizontal vaporizer with a thin film surface of 0.1493 / m3. At the same time, 250 standard liters per minute of nitrogen was fed to the lower inlet 18 of chamber 12 at a pressure of about 50 psi and the contents of the evaporation chamber 12 heated to a temperature of about 160 ° C. A reactant stream of about 50 standard liters per minute of dimethyltin dichloride evaporated and about 250 standard liters per minute of nitrogen (16.5% of the gas phase was dimethyltin dichloride) was withdrawn from the vaporization chamber 12 from outlet 25 located at the opposite end of chamber 12 to inlets 17 and 18. The stream of reactants was then heated and combined with about 50 standard liters per minute of oxygen and about 23 standard liters per minute of steam. At this point, the mixture contained approximately 13% gas phase dimethyltin dichloride. The combined reactant stream was directed at the surface of the hot glass substrate produced by the liquid glass process at a temperature of about 627 ° C to obtain a uniform tin oxide coating deposited at a rate of about 2200 A per second.
The above-mentioned parameters for dimethyltin dichloride work equally well for a precursor mixture containing 95% by weight of dimethyltin dichloride and 5% by weight of methyltin trichloride.
1 sheet
Sheet 1
42 members in 28 offices
Priority claims8
| Document | Office | Kind | Date |
|---|---|---|---|
| 42263689 | United States of America | A | |
| 42263689 | United States of America | A | |
| 59112190 | United States of America | A | |
| 59112190 | United States of America | A | |
| 89422636 | – | – | – |
| 90591121 | – | – | – |
| US19890422636 | – | – | – |
| US19900591121 | – | – | – |
Members42
| Document | Office | Kind | |
|---|---|---|---|
| CA2027761A1 | Canada | A1 | |
| IE903601A1 | Ireland | A1 | |
| WO9105743A1 | World Intellectual Property Organization (WIPO) | A1 | |
| AU6529790A | Australia | A | |
| CN1051899A | China | A | |
| FI912845A0 | Finland | A0 | |
| NO912320D0 | Norway | D0 | |
| NO912320L | Norway | L | |
| ZA908296B | South Africa | B | |
| PT95613A | Portugal | A | |
| BR9005227A | Brazil | A | |
| EP0450016A1 | European Patent Office (EPO) | A1 | |
| HU907561D0 | Hungary | D0 | |
| HUT57682A | Hungary | A | |
| US5090985A | United States of America | A | |
| JPH04502305A | Japan | A | |
| KR920701064A | Republic of Korea | A | |
| AU632175B2 | Australia | B2 | |
| NZ235700A | New Zealand | A | |
| EP0450016A4 | European Patent Office (EPO) | A4 | |
| TR25795A | Türkiye | A | |
| YU194490A | Yugoslavia, later Serbia and Montenegro (until 2006) | A | |
| BG94619A | Bulgaria | A | |
| MX173282B | Mexico | B | |
| CN1025322C | China | C | |
| PL167110B1This record | Poland | B1 | |
| MY107107A | Malaysia | A | |
| YU47521B | Yugoslavia, later Serbia and Montenegro (until 2006) | B | |
| EP0450016B1 | European Patent Office (EPO) | B1 | |
| AT133147T | Austria | T | |
| ATE133147T1 | Austria | T1 | |
| DE69024938D1 | Germany | D1 | |
| ES2082007T3 | Spain | T3 | |
| RU2062258C1 | Russian Federation | C1 | |
| DE69024938T2 | Germany | T2 | |
| RO111756B1 | Romania | B1 | |
| PT95613B | Portugal | B | |
| HU213646B | Hungary | B | |
| KR0147042B1 | Republic of Korea | B1 | |
| CZ502090A3 | Czechia | A3 | |
| NO304109B1 | Norway | B1 | |
| JP3078835B2 | Japan | B2 |
Numbers
- Publication, DOCDB
- 167110
- Publication, EPODOC
- PL167110B
- Application
- 90287364
- Application, DOCDB
- 28736490
- Application, EPODOC
- PL19900287364
Titles
- English
- METHOD FOR MAKING EVAPORATED REAGENTS FOR CHEMICAL DEPOSITION OF VAPOURS
Classification
- CPC, 6
- C03C17/245
- C03B37/01413
- C03B2207/85
- C03C2217/229
- C03C2218/152
- C23C16/4481
- IPC, 7
- C03C17 22
- B05D5 06
- C03B37 014
- C03C17 245
- C23C16 40
- C23C16 44
- C23C16 448