Method and apparatus for removing residual hydrogen from a purified gas

Abstract

The invention relates generally to a gas purification system for the purification of noble gasses and nitrogen. An improved method of purification generally includes the following steps: (a) heating an impure gas; (b) contacting the impure gas with an impurity sorbing material to produce a purified gas; (c) cooling the purified gas to a temperature less than about 100° C.; and (d) contacting the purified gas with a hydrogen sorbing gas to remove residual hydrogen. The system includes an improved heat exchange apparatus for cooling the purified gas and a low temperature hydrogen sorption apparatus.

What is claimed is: 
     
       1. A method for removing residual hydrogen from a purified gas comprising the steps of: (a) heating an impure gas;   (b) contacting the heated impure gas with an impurity sorbing material to produce a purified gas having trace amounts of residual hydrogen;   (c) cooling the purified gas to a temperature less than about 100° C.; and   (d) contacting the cooled purified gas with a hydrogen sorbing material to at least partially remove said residual hydrogen.   
     
     
       2. A method as recited in claim 1 wherein the impure gas is heated to more than about 200° C. 
     
     
       3. A method as recited in claim 2 wherein the purified gas is cooled to less than about 60° C. 
     
     
       4. A method as recited in claim 3 wherein the purified gas is cooled to less than about 40° C. 
     
     
       5. A method as recited in claim 1 wherein said impure gas includes at least a component which is selected from the group consisting essentially of nitrogen, helium, neon, argon, krypton, xenon, and radon. 
     
     
       6. A method as recited in claim 1 wherein said impurity sorbing material includes a non-evaporative getter material selected from the group consisting essentially of zirconium-vanadium-iron alloys and zirconium-iron alloys. 
     
     
       7. A method as recited in claim 1 wherein said hydrogen sorbing material includes a material selected from the group consisting essentially of zirconium, palladium, platinum, rhodium, ruthenium, nickel, titanium, and alloys thereof. 
     
     
       8. A method as recited in claim 7 wherein said hydrogen sorbing material includes a non-evaporative getter material selected from the group consisting essentially of zirconium-vanadium-iron alloys and zirconium-iron alloys. 
     
     
       9. A method as recited in claim 1 wherein said step of cooling said purified gas comprises flowing said purified gas through at least one conduit, wherein said conduit has a substantially constant wall temperature which is less than about 100° C. 
     
     
       10. A gas purification system comprising: (a) gas inlet means for impure gas;   (b) heating means coupled to said gas inlet means for heating said impure gas to a temperature greater than about 200° C.;   (c) purifier means coupled to said heating means, said purifier means including a getter material capable of removing impurities from said impure gas to produce a purified gas;   (d) cooling means coupled to said purifier means for cooling said purified gas to a temperature less than about 100° C.;   (e) hydrogen sorbing means coupled to said cooling means which includes a hydrogen sorbing material to remove residual hydrogen from said purified gas; and   (f) a gas outlet for said purified gas.   
     
     
       11. A gas purification system as recited in claim 10 wherein said impure gas is heated to about 300°-450° C. by said heating means and said purified gas is cooled to less than about 60° C. by said cooling means. 
     
     
       12. A gas purification system as recited in claim 10 wherein said getter material comprises a non-evaporative getter alloy selected from the group consisting essentially of zirconium-vanadium-iron alloys and zirconium-iron alloys. 
     
     
       13. A gas purification system as recited in claim 10 wherein said hydrogen sorbing material is selected from the group consisting essentially of zirconium, palladium, platinum, rhodium, ruthenium, nickel, titanium, and alloys thereof. 
     
     
       14. A gas purification system as recited in claim 10 wherein said hydrogen sorbing material comprises a non-evaporative getter alloy selected from the group consisting essentially of zirconium-vanadium-iron alloys and zirconium-iron alloys. 
     
     
       15. A gas purification system as recited in claim 10 wherein said cooling means comprises: (a) a first manifold, including a first plurality of integral connector nipples;   (b) a second manifold, including a second plurality of integral connector nipples aligned with said connector nipples of said first manifold;   (c) a plurality of straight tubes, each tube extending between a first connector nipple on said first manifold and a second connector nipple on said second manifold, each of said straight tubes being welded in place at the first manifold and at the second manifold.   
     
     
       16. A gas purification system as recited in claim 15 wherein said cooling means further comprises heat sink means contacting said plurality of straight tubes to maintain the temperature of said tubes at a substantially constant temperature along their lengths. 
     
     
       17. A gas purification system as recited in claim 16 wherein said heat sink means comprises a first plate contacting said plurality of tubes on a first side thereof and a second plate contacting said plurality of tubes on second side thereof. 
     
     
       18. A gas purification system as recited in claim 16 further comprising means for removing heat energy from said heat sink means. 
     
     
       19. A heat exchange apparatus comprising: (a) a first monoblock manifold formed from a single piece of material and including a first plurality of integral connector nipples such that interior surfaces of said first plurality of connector nipples do not include a joint between a plurality of pieces;   (b) a second monoblock manifold formed from a single piece of material and including a second plurality of integral connector nipples aligned with said connector nipples of said first manifold such that interior surfaces of said second plurality of connector nipples do not include a joint between a plurality of pieces;   (c) a plurality of straight tubes, each tube extending between a first connector nipple on said first manifold and a second connector nipple on said second manifold, each of said straight tubes being welded in place at the first manifold and at the second manifold.   
     
     
       20. A heat exchange apparatus as recited in claim 19 further comprising heat sink means contacting said plurality of straight tubes to maintain the temperature of said tubes at a substantially constant temperature along their lengths. 
     
     
       21. A gas purification system as recited in claim 20 wherein said heat sink means comprises a first plate contacting said plurality of tubes on a first side thereof and a second plate contacting said plurality of tubes on a second side thereof. 
     
     
       22. A gas purification system as recited in claim 21 further comprising means for removing heat energy at least one of said first plate and said second plate. .Iadd. 
     
     
       23.  A gas purification system comprising: a) gas inlet means for impure gas;   b) heating means having a heater inlet and a heater outlet, said heater inlet being coupled to said gas inlet, said heating means being for pre-heating said impure gas to a temperature greater than about 200° C.;   c) purifier means having a purifier inlet and a purifier outlet, said purifier inlet being coupled to said heater outlet, said purifier means including a getter material housed within a purifier vessel, said getter material being capable of removing impurities from said impure gas to produce a purified gas;   d) cooling means having a cooling means inlet and a cooling means outlet, said cooling means inlet being coupled to said purifier outlet by a first length of tubing such that said cooling means can pre-cool said purified gas to a pre-cooled temperature less than about 100° C., said cooling means being separate from said purifier means;   e) hydrogen sorbing means having a hydrogen sorber inlet and a hydrogen sorber outlet, said hydrogen sorber inlet being coupled to said cooling means outlet by a second length of tubing, said hydrogen sorbing means including a hydrogen sorbing material housed within a hydrogen sorber vessel which is separate from said purifier vessel, said hydrogen sorbing means being operative to remove residual hydrogen from said purified gas; and   f) a gas outlet coupled to said hydrogen sorber outlet for releasing said purified gas. .Iaddend..Iadd.24. A gas purification system as recited in claim 23 wherein said impure gas is pre-heated to about 300°-450° C. by said heating means and said purified gas is pre-cooled to less than about 60° C. by said cooling means. .Iaddend..Iadd.25. A gas purification system as recited in claim 23 wherein said getter material comprises a non-evaporative getter alloy selected from the group consisting essentially of zirconium-vanadium-iron   
     
     
        alloys and zirconium-iron alloys. .Iaddend..Iadd.26.  A gas purification system as recited in claim 23 wherein said hydrogen sorbing material is selected from the group consisting essentially of zirconium, palladium, platinum, rhodium, ruthenium, nickel, titanium, and alloys thereof. .Iaddend..Iadd.27. A gas purification system as recited in claim 26 wherein said hydrogen sorbing material comprises a non-evaporative getter alloy selected from the group consisting essentially of zirconium-vanadium-iron alloys and zirconium-iron alloys. .Iaddend..Iadd.28. A gas purification system as recited in claim 23 wherein said cooling means comprises: a) a first manifold, including a first plurality of integral connector nipples;   b) a second manifold, including a second plurality of integral connector nipples aligned with said connector nipples of said first manifold;   c) a plurality of straight tubes, each tube extending between a first connector nipple on said first manifold and a second connector nipple on said second manifold, each of said straight tubes being welded in place at the first manifold and at the second manifold. .Iaddend..Iadd.29. A gas purification system as recited in claim 25 wherein said cooling means further comprises heat sink means contacting said plurality of straight tubes to maintain the temperature of said tubes at a substantially constant temperature along their lengths. .Iaddend..Iadd.30. A gas purification system as recited in claim 25 wherein said heat sink means comprises a first plate contacting said plurality of tubes on a first side thereof and a second plate contacting said plurality of tubes on a second side thereof. .Iaddend..Iadd.31. A method for producing a semiconductor device under a high purity atmosphere, comprising the steps of:   a) heating an impure gas;   b) contacting the heated impure gas with impurity absorbing material to produce a purified gas having trace amounts of residual hydrogen;   c) cooling the purified gas to a temperature less than about 100° C.;   d) contacting the cooled purified gas with a hydrogen sorbing material to at least partially remove said residual hydrogen from said purified gas;   e) introducing said purified gas after said at least partial removal of said residual hydrogen to a semiconductor wafer processing chamber; and   f) processing a semiconductor wafer in the processing chamber to produce at   
     
     
        least one semiconductor device. .Iaddend..Iadd.32.  The method as recited in claim 31, wherein said impure gas is heated to a temperature greater than about 200° C. .Iaddend..Iadd.33. The method as recited in claim 31, wherein said purified gas is cooled to a temperature of less than about 60° C. .Iaddend..Iadd.34. The method as recited in claim 33, wherein said purified gas is cooled to a temperature of less than about 40° C. .Iaddend..Iadd.35. The method as recited in claim 31, wherein said step of cooling said purified gas further comprises flowing said purified gas through at least one conduit having a wall temperature which is less than about 100° C. .Iaddend..Iadd.36. A method as recited in claim 31 wherein said gas includes at least a component which is selected from the group consisting essentially of nitrogen, helium, neon, argon, krypton, xenon, and radon. .Iaddend..Iadd.37. A method as recited in claim 33 wherein said impurity sorbing material includes a non-evaporative getter material selected from the group consisting essentially of zirconium-vanadium-iron alloys and zirconium-iron alloys. .Iaddend..Iadd.38. A method as recited in claim 33 wherein said hydrogen sorbing material includes a material selected from the group consisting essentially of zirconium, palladium, platinum, rhodium, ruthenium, nickel, titanium, and alloys thereof. .Iaddend..Iadd.39. A method as recited in claim 38 wherein said hydrogen sorbing material includes a non-evaporative getter material selected from the group consisting essentially of zirconium-vanadium-iron alloys and zirconium-iron alloys. 
     
     
        .Iaddend..Iadd.  .  The method of claim 31, wherein said step of processing includes subjecting said semiconductor wafer to at least one process selected from the group consisting of chemical vapor deposition and plasma etching. .Iaddend.