Method for preparing vaporized reactants for chemical vapor deposition

• US 5,090,985 A
• Filed: 10/04/1990
• Issued: 02/25/1992
• Est. Priority Date: 10/17/1989
• Status: Expired due to Term

• Current Assignee: Libbey-Owens-Ford Company Toledo Oh A Corporation of
• Original Assignee: Libbey-Owens-Ford Co. (Eaton Corporation PLC.)
• Inventors: Soubeyrand, Michel J., McCurdy, Richard J.
• Primary Examiner(s): LINDSAY JR, ROBERT
• Application Number:
  US07/591,121
• Time in Patent Office: 509 Days
• Field of Search: 427/255.3, 427/314, 427/255.1, 427/248.1, 427/166, 427/167, 65/60.52, 65/60.8
• US Class Current: 65/60.52
• CPC Class Codes: C03B 2207/85 with vapour generated from liquid glass precursors, e.g. directly by heating the liquid
• CPC Class Codes: C03B 37/01413 Reactant delivery systems C03B37/01807 takes precedence; devices therefor in general B01D1/00, B01J4/00
• CPC Class Codes: C03C 17/245 by deposition from the vapour phase
• CPC Class Codes: C03C 2217/229 Non-specific enumeration
• CPC Class Codes: C03C 2218/152 by cvd
• CPC Class Codes: C23C 16/4481 by evaporation using carrier gas in contact with the source material C23C16/4486 takes precedence

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.

Claims

1. A process for preparing vaporized reactants, comprising the steps of:

A) providing a coating precursor selected from metal or silicon compounds at a temperature above its melting point but substantially below its standard vaporization temperature, thereby causing the coating precursor to be in the form of a liquid;

B) simultaneously and continually performing the steps of;

i) injecting the liquid coating precursor into a vaporization chamber, defined in part by at least one peripheral wall, wherein the liquid coating precursor produces a vapor;

ii) admitting to the vaporization chamber a blend gas in an amount sufficient to increase the mass transport of the coating precursor vapor and thus cause accelerated vaporization of the liquid coating precursor;

iii) mixing the liquid coating precursor, coating precursor vapor and blend gas, including dispensing the liquid precursor as a thin film along said chamber wall;

whereby the liquid coating precursor is completely vaporized at a temperature below its standard vaporization temperature, to prepare a vaporized reactant gas stream having a high, uniform concentration of coating precursor; and

C) conveying the reactant gas stream away from the vaporization chamber and into contact with a substrate.

2. The process for preparing vaporized reactants, according to claim 1, wherein the coating precursor is preheated before being injected into the vaporization chamber, but to a temperature less than its standard vaporization temperature.

3. The process for preparing vaporized reactants, according to claim 1, wherein said at least one wall of the vaporization chamber is heated.

4. The process for preparing vaporized reactants, according to claim 2, wherein said at least one wall of the vaporization chamber is heated to a temperature greater than said preheat temperature but below the standard vaporization temperature of the liquid coating precursor.

5. The process for preparing vaporized reactants, according to claim 1, wherein the blend gas is preheated to about the temperature of the vaporization chamber prior to being injected thereinto.

6. The process for preparing vaporized reactants, according to claim 1, wherein the vaporization chamber comprises a horizontal thin film evaporator.

7. The process for preparing vaporized reactants, according to claim 6, wherein the thin film evaporator includes an upper inlet at an end of the horizontal thin film evaporator and a lower inlet at the same end of the evaporator as the upper inlet, and further wherein the liquid coating precursor is injected into the evaporator through the upper inlet, and the blend gas is admitted to the evaporator through the lower inlet.

8. A process for preparing vaporized reactants, comprising the steps of:

A) providing a coating precursor selected from metal or temperature above its melting point but substantially below its standard vaporization temperature, thereby causing the coating precursor to be in the form of a liquid;

B) simultaneously and continually performing the steps of;

i) injecting the liquid coating precursor into a vaporization chamber, wherein the liquid coating precursor produces a vapor;

ii) admitting to the vaporization chamber a blend gas in an amount sufficient to increase the mass transport of the coating precursor vapor and thus cause accelerated vaporization of the liquid coating precursor;

iii) heating the liquid coating precursor, coating precursor vapor, and blend gas, to a temperature greater than the temperature of step A but below the coating precursor'"'"'s standard vaporization temperature; and

iv) mixing the coating precursor, vapor and blend gas;

whereby the liquid coating precursor is completely vaporized at a temperature below its standard vaporization temperature, to prepare a vaporized reactant gas stream having a high, uniform concentration of coating precursor in a blend gas;

C) conveying the reactant gas stream away from the vaporization chamber; and

D) contacting said reactant gas stream with a float glass ribbon substrate maintained at a temperature of at least 750°

F.

9. The process for preparing vaporized reactants, according to claim 8, wherein said contact of said reactant gas stream and substrate takes place in the presence of oxygen.

10. The process for preparing vaporized reactants according to claim 8, wherein said contact of said reactant gas stream with said substrate takes place while said ribbon is supported on a bath of molten metal and is at a temperature in the range of about 1100°

F. to about 1250°

F.

11. The process for preparing vaporized reactants, according to claim 8, wherein the coating precursor is selected from the group consisting of dimethyltin dichloride, tetraethoxysilane, diethyltin dichloride, dibutyltin diacetate, tetramethyl tin, methyltin trichloride, triethyltin chloride, trimethyltin chloride, tetrabutyl titanate, titanium tetrachloride, titanium tetraisopropoxide, triethylaluminum, diethylaluminum chloride, trimethylaluminum, aluminum acetylacetonate, aluminum ethylate, diethyldichlorosilane, methyltriethoxysilane, zinc acetylacetonate, zinc propionate, and mixtures thereof.

12. The process for preparing vaporized reactants, according to claim 11, wherein the coating precursor is dimethyltin dichloride.

13. The process for preparing vaporized reactants, according to claim 11, wherein the coating precursor is 95 percent by weight dimethyltin dichloride and 5 percent by weight methyltin trichloride.

14. The process for preparing vaporized reactants, according to claim 11, wherein the blend gas is selected from the group consisting of helium, nitrogen, hydrogen, argon, and mixtures thereof.

15. The process for preparing vaporized reactants, according to claim 11, wherein the liquid coating precursor is injected into the vaporization chamber at a temperature of from about 70°

F. to about 530°

F.

16. The process for preparing vaporized reactants, according to claim 11, wherein the liquid coating precursor, coating precursor vapor, and blend gas are heated in the vaporization chamber to a temperature from about 95°

F. to about 555°

F.

17. The process for preparing vaporized reactants, according to claim 11, wherein the liquid coating precursor is injected into the vaporization chamber at a rate from about 0.5 to about 120 pounds per hour.

18. The process for preparing vaporized reactants, according to claim 11, wherein the blend gas is admitted to the vaporization chamber at a pressure from about 2 to about 15 psig.

19. The process for preparing vaporized reactants, according to claim 11, wherein the blend gas is admitted to the vaporization chamber at a rate from about 100 to about 400 standard liters per minute.

20. A process for preparing vaporized reactants, comprising the steps of:

A) providing a coating precursor selected from the group consisting of dimethyltin dichloride, tetraethoxysilane, diethyltin dichloride, dibutyltin diacetate, tetramethyl tin, methyltin trichoride, triethyltin chloride, trimethyltin chloride, tetrabutyl titanate, titanium tetrachloride, titanium tetraisopropoxide, triethylaluminum, diethylaluminum chloride, trimethylaluminum, aluminum acetylacetonate, aluminum ethylate, diethyldichlorosilane, methyltriethoxysilane, zinc acetylacetonate, zinc propionate and mixtures thereof, at a temperature above its melting point but substantially below its standard vaporization temperature and in the range from about 70°

F. to about 530°

F., thereby causing the coating precursor to be in the form of a liquid;

B) simultaneously and continually performing the steps of;

i) injecting the liquid coating precursor, at a rate from about 0.5 to about 120 pounds per hour, into a vaporization chamber defined in part by at least one peripheral wall, wherein the liquid coating precursor produces a vapor;

ii) admitting to the vaporization chamber a blend gas selected from the group consisting of helium, nitrogen, hydrogen, argon and mixtures thereof in an amount in the range from about 25 to about 500 standard liters per minute and at a pressure from about 2 to about 15 psig;

iii) heating the liquid coating precursor, coating precursor vapor, and blend gas, to a temperature greater than the temperature of step A but below the coating precursor'"'"'s standard vaporization temperature and in the range from about 95°

F. to about 555°

F.; and

iv) mixing the liquid coating precursor, coating precursor vapor and blend gas including dispensing the liquid precursor as a thin film along said chamber wall;

whereby the liquid coating precursor is completely vaporized at a temperature below its standard vaporization temperature, to prepare a vaporized reactant gas stream having a high, uniform concentration of coating precursor;

C) conveying the reactant gas stream away from the vaporization chamber; and

D) contacting said reactant gas stream with a float glass ribbon substrate maintained at a temperature of at least 750°

F.

21. A process for preparing vaporized, reactants, comprising the steps of:

A) providing a metal coating precursor, selected from the group consisting of dimethyltin dichloride, tetraethoxysilane, diethyltin dichloride, dibutyltin diacetate, tetramethyl tin, methyltin trichloride, triethyltin chloride, trimethyltin chloride, tetrabutyl titanate, titanium tetrachloride, titanium tetraisopropoxide, triethylaluminum, diethylaluminum chloride, trimethylaluminum, aluminum acetylacetonate, aluminum ethylate, zinc acetylacetonate, zinc propionate and mixtures thereof, at a temperature above its melting point but substantially below its standard vaporization temperature and in the range from about 70°

F. to about 530°

F., thereby causing the metal coating precursor to be in the form of a liquid;

B) simultaneously and continually performing the steps of;

i) injecting the liquid metal coating precursor, at a rate from about 0.5 to about 120 pounds per hour, into a vaporization chamber defined in part by at least one peripheral wall, wherein the liquid metal coating precursor produces a vapor;

ii) admitting to the vaporization chamber a blend gas selected from the group consisting of helium, nitrogen, hydrogen, argon and mixtures thereof in an amount in the range from about 25 to about 500 standard liters per minute and at a pressure from about 2 to about 15 psig in an amount to thus cause accelerated vaporization of the liquid metal coating precursor;

iii) heating the liquid metal coating precursor, metal coating precursor vapor, and blend gas, to a temperature greater than the temperature of step A but below the metal coating precursor'"'"'s standard vaporization temperature and in the range from about 95°

F. to about 555°

F.; and

iv) mixing the liquid metal coating precursor, metal coating precursor vapor and blend gas including dispensing the liquid metal coating precursor as a thin film along said chamber wall;

whereby the liquid metal coating precursor is completely vaporized at a temperature below its standard vaporization temperature, to prepare a vaporized reactant gas stream having a high, uniform concentration of metal coating precursor in a blend gas;

C) conveying the reactant gas stream away from the vaporization chamber; and

D) contacting said reactant gas stream with a float glass ribbon substrate maintained at a temperature of at least 750°

F.

22. The process for preparing vaporized reactants, according to claim 21, wherein the vaporization chamber comprises a horizontal thin film evaporator.

23. The process for preparing vaporized reactants, according to claim 22, wherein the thin film evaporator includes an upper inlet at an end of the horizontal thin film evaporator and a lower inlet at the same end of the evaporator as the upper inlet, and further wherein the liquid coating precursor is injected into the evaporator through the upper inlet, and the blend gas is admitted to the evaporator through the lower inlet.

24. The process for preparing vaporized reactants, according to claim 23, wherein the blend gas is selected from the group consisting of helium, nitrogen and mixtures thereof.

25. A process for preparing vaporized reactants, comprising the steps of:

A) providing dimethyltin dichloride at a temperature in the range of about 225°

F. to about 375°

F., thereby causing the dimethyltin dichloride to be in the form of a liquid;

B) simultaneously and continually performing the steps of;

i) injecting the liquid dimethyltin dichloride, at a rate of about 1 to about 75 pounds per hour, into a horizontal thin film evaporator defined in part by at least one peripheral wall, wherein the liquid dimethyltin dichloride produces a vapor;

ii) admitting to the horizontal thin film evaporator a blend gas selected from the group consisting of helium, nitrogen and mixtures thereof, in an amount in the range from about 25 to about 500 standard liters per minute and at a pressure from about 2 to about 15 psig to thus cause accelerated vaporization of the liquid dimethyltin dichloride;

iii) heating the liquid dimethyltin dichloride, dimethyltin dichloride vapor and blend gas to a temperature greater than the temperature of step A but below the standard vaporization temperature of dimethyltin dichloride and in the range of from about 250°

F. to about 400°

F.; and

iv) mixing the liquid dimethyltin dichloride, dimethyltin dichloride vapor and blend gas, including dispensing the liquid dimethyltin dichloride as a thin film along said evaporator wall;

whereby the liquid dimethyltin dichloride is completely vaporized at a temperature below its standard vaporization temperature, to prepare a vaporized reactant gas stream having a high, uniform concentration of dimethyltin dichloride in a blend gas; and

C) conveying the reactant gas stream away from the horizontal thin film evaporator and into contact with a substrate.

26. A process for depositing coatings on glass comprising:

A) forming a vaporized reactant gas stream including the mixture of dimethyltin dichloride vapor and blend gas produced in accordance with claim 25; and

B) contacting said reactant gas stream with a float glass ribbon substrate maintained at a temperature of at least 750°

F.

27. A process for depositing coatings on glass, according to claim 26, wherein said contact of said reactant gas stream and glass ribbon takes place in the presence of oxygen, and while said ribbon is supported on a bath of molten metal and is at a temperature in the range of about 1100°

F. to about 1250°

F.

30. The process for preparing vaporized reactants, according to claim 27, wherein the vaporized reactant gas stream is utilized to form a coating on hot glass at a growth rate up to about 2,200 Angstroms per second.

28. A process for preparing vaporized reactants, comprising the steps of:

A) providing a mixture of 95 weight percent dimethyltin dichloride and 5 weight percent methyltin trichloride at a temperature in the range of about 225°

F. to about 375°

F., thereby causing the mixture to be in the form of a liquid;

B) simultaneously and continually performing the steps of;

i) injecting the liquid dimethyltin dichloride-methyltin trichloride mixture, at a rate of about 1 to about 75 pounds per hour, into a horizontal thin film evaporator defined in part by at least one peripheral wall, wherein the liquid mixture produces a vapor;

ii) admitting to the horizontal thin film evaporator a blend gas selected from the group consisting of helium, nitrogen and mixtures thereof, in an amount in the range from about 25 to about 500 standard liters per minute and at a pressure from about 2 to about 15 psig to thus cause accelerated vaporization of the liquid mixture;

iii) heating the liquid dimethyltin dichloride-methyltin trichloride mixture, the vaporized dimethyltin dichloride-methyltin trichloride mixture, and blend gas to a temperature greater than the temperature of step A and in the range of from about 250°

F. to about 400°

F.;

iv) mixing the liquid dimethyltin dichloride-methyltin trichloride mixture, the vaporized dimethyltin dichloride-methyltin trichloride, and blend gas including dispensing the liquid dimethyltin dichloride-methyltin trichloride as a thin film along said evaporator wall;

whereby the liquid dimethyltin dichloride-methyltin trichloride mixture is completely vaporized, to prepare a vaporized reactant gas stream having a high, uniform concentration comprised of 95 weight percent dimethyltin dichloride and 5 weight percent methyltin trichloride;

C) conveying the vaporized reactant gas stream away from the horizontal thin film evaporator and into contact with a substrate.

29. A process for depositing tin oxide coatings on glass comprising:

A) forming a vaporized reactant gas stream including the dimethyltin dichloride-methyltin trichloride and blend gas mixture produced in accordance with claim 28; and

B) contacting said reacting gas stream with a float glass substrate, in the presence of oxygen, while said ribbon is supported on a bath of molten metal and at a temperature in the range of about 1100°

F. to about 1250°

F.

31. The process for depositing tin oxide coatings on glass, according to claim 29, wherein the vaporized reactant gas stream is utilized to form a tin oxide coating on the glass ribbon at a growth rate up to about 2,200 Angstroms per second.