Methods and equipment for depositing high quality reflective coatings

Abstract

Methods and equipment for depositing coatings on glass and other substrates. In some embodiments, methods and equipment are provided for depositing reflective thin film coatings, such as low-emissivity coatings that are particularly reflective of infrared radiation, optionally by a downward coating operation. In some embodiments, such a downward coating operation is coupled with an upward coating operation used to deposit another coating.

1 . A method for depositing film onto a glass sheet, the method comprising: 
 a) providing a coater having a path of substrate travel extending through the coater, the coater including downward coating equipment mounted above the path of substrate travel;    b) conveying the glass sheet along the path of substrate travel in a generally horizontal orientation wherein a top major surface of the glass sheet is oriented upwardly and a bottom major surface of the glass sheet is oriented downwardly; and    c) operating the downward coating equipment to deposit upon the top major surface of the glass sheet a coating including a sequence of at least seven film regions comprising, moving outwardly from the top major surface of the glass sheet, a first transparent dielectric film region, a first infrared-reflective film region comprising silver, a second transparent dielectric film region, a second infrared-reflective film region comprising silver, a third transparent dielectric film region, a third infrared-reflective film region comprising silver, and a fourth transparent dielectric film region;    the method comprising depositing said at least seven film regions in a single pass of the glass sheet through the coater, and wherein during this single pass the glass sheet is conveyed at a conveyance rate exceeding 275 inches per minute.    
   
   
       2 . The method of  claim 1  wherein the coater has an upward sputtering section and a downward sputtering section, the upward sputtering section being characterized by a series of lower targets mounted at a lower elevation than the path of substrate travel, the downward sputtering section being characterized by a series of upper targets mounted at a higher elevation than the path of substrate travel, wherein oxidizing sputtering atmospheres are maintained in all sputtering chambers of the upward sputtering section, and wherein nitriding sputtering atmospheres are maintained in a plurality of sputtering chambers of the downward sputtering section, the method comprising reactively sputtering all the lower targets upwardly in oxidizing gas and reactively sputtering a plurality of the upper targets downwardly in nitriding gas.  
   
   
       3 . The method of  claim 1  wherein the conveyance rate is 300 inches per minute or faster.  
   
   
       4 . The method of  claim 1  wherein said infrared-reflective film regions are deposited by sputtering silver-containing targets at an average power exceeding 8.5 kW.  
   
   
       5 . The method of  claim 1  wherein the conveyance rate is 310 inches per minute or faster, said infrared-reflective film regions are deposited by sputtering silver-containing targets, and at least one of the silver-containing targets is sputtered at a power exceeding 12 kW.  
   
   
       6 . The method of  claim 1  wherein said infrared-reflective film regions are deposited by sputtering silver-containing targets, a first power level is used for sputtering a silver-containing target in depositing the first infrared-reflective film region, a second power level is used for sputtering a silver-containing target in depositing the second infrared-reflective film region, and a third power level is used for sputtering a silver-containing target in depositing the third infrared-reflective film region, the third power level being greater than the second power level, and the second power level being greater than the first power level.  
   
   
       7 . The method of  claim 1  wherein the coater has an extended series of sputtering chambers and includes upward coating equipment mounted below the path of substrate travel, the upward coating equipment comprising lower sputter targets mounted at a lower elevation than the path of substrate travel, the downward coating equipment comprising upper sputter targets mounted at a higher elevation than the path of substrate travel, wherein the coater's extended series of sputtering chambers includes at least 39 downward sputtering chambers each including at least one of the upper sputter targets.  
   
   
       8 . The method of  claim 7  wherein the coater's extended series of sputtering chambers includes at least 55 sputtering chambers.  
   
   
       9 . The method of  claim 7  wherein the downward coating equipment is operated to deposit said coating upon the top major surface of the glass sheet, including: depositing at least 50 angstroms of transparent dielectric film between the top major surface of the glass sheet and the first infrared-reflective film region; depositing at least 100 angstroms of transparent dielectric film between the first and second infrared-reflective film regions; depositing at least 100 angstroms of transparent dielectric film between the second and third infrared-reflective film regions; and depositing at least 50 angstroms of transparent dielectric film over the third infrared-reflective film region.  
   
   
       10 . The method of  claim 9  wherein said operation of the downward coating equipment includes: depositing no more than 175 angstroms of transparent dielectric film between the top major surface of the glass sheet and the first infrared-reflective film region.  
   
   
       11 . The method of  claim 1  wherein the coater has an extended series of sputtering chambers including at least 60 sputtering chambers, the glass sheet has a major dimension of at least 2 meters, and the method comprises entirely coating both the top and bottom major surfaces of the glass sheet in said single pass of the glass sheet through the coater.  
   
   
       12 . The method of  claim 1  wherein said single pass of the glass sheet through the coater is continuous in that the glass sheet is not interrupted by removing the glass sheet from the coater during said single pass.  
   
   
       13 . The method of  claim 1  wherein said conveyance rate is maintained substantially constant throughout an entirety of said single pass of the glass sheet through the coater.  
   
   
       14 . A coater having an extended series of sputtering chambers and a substrate support defining a path of substrate travel extending through all the sputtering chambers of the coater, wherein the substrate support is adapted for conveying along the path of substrate travel a sheet-like substrate having a major dimension of greater than 2.0 meters, the coater having an upward sputtering section and a downward sputtering section, the upward sputtering section being characterized by a series of lower targets mounted at lower elevation than the path of substrate travel, the downward sputtering section being characterized by a series of upper targets mounted at higher elevation than the path of substrate travel, the downward sputtering section having at least 39 downward sputtering chambers each including at least one of the upper targets, the upward sputtering section having a plurality of upward sputtering chambers each including at least one of the lower targets, wherein the downward sputtering chambers of the downward sputtering section form at least seven downward deposition systems comprising, in sequence along the path of substrate travel, a first downward deposition system adapted for depositing a first transparent dielectric film region, a second downward deposition system adapted for depositing a first infrared-reflective film region comprising silver, a third downward deposition system adapted for depositing a second transparent dielectric film region, a fourth downward deposition system adapted for depositing a second infrared-reflective film region comprising silver, a fifth downward deposition system adapted for depositing a third transparent dielectric film region, a sixth downward deposition system adapted for depositing a third infrared-reflective film region comprising silver, and a seventh downward deposition system adapted for depositing a fourth transparent dielectric film region.  
   
   
       15 . The coater of  claim 14  wherein the downward sputtering section has at least 42 downward sputtering chambers.  
   
   
       16 . The coater of  claim 14  wherein the downward sputtering section has at least 45 downward sputtering chambers.  
   
   
       17 . The coater of  claim 14  wherein the coater's extended series of sputtering chambers includes at least 60 sputtering chambers.  
   
   
       18 . The coater of  claim 14  wherein the coater's extended series of sputtering chambers includes at least 63 sputtering chambers.  
   
   
       19 . The coater of  claim 14  wherein the path of substrate travel is a substantially straight path and the coater is a vacuum coater.  
   
   
       20 . The coater of  claim 14  wherein the substrate support comprises spaced-apart transport rollers, the coater being provided in combination with a plurality of sheet-like glass substrates, the substrates being in direct physical contact with a plurality of the transport rollers.  
   
   
       21 . A method for depositing film onto a glass sheet, the method comprising: 
 a) providing a coater having an extended series of sputtering chambers and a path of substrate travel extending through all the sputtering chambers of the coater, wherein the coater's extended series of sputtering chambers includes at least 60 sputtering chambers at least some of which are adapted for downward sputtering and include upper sputtering targets mounted above the path of substrate travel;    b) conveying the glass sheet along the path of substrate travel in a generally horizontal orientation wherein a top major surface of the glass sheet is oriented upwardly and a bottom major surface of the glass sheet is oriented downwardly, the glass sheet being conveyed along at least a portion of the path of substrate travel at a conveyance rate of 300 inches per minute or faster; and    c) sputtering at least a plurality of the upper targets to deposit upon the top major surface of the glass sheet a coating comprising, moving outwardly from the top major surface of the glass sheet, a first transparent dielectric film region, a first infrared-reflective film region comprising silver, a second transparent dielectric film region, a second infrared-reflective film region comprising silver, a third transparent dielectric film region, a third infrared-reflective film region comprising silver, and a fourth transparent dielectric film region.    
   
   
       22 . The method of  claim 21  wherein the conveyance rate is 310 inches per minute or faster.  
   
   
       23 . The method of  claim 21  wherein said infrared-reflective film regions are deposited by sputtering at least three silver-containing targets at an average power exceeding 8.5 kW.  
   
   
       24 . The method of  claim 23  wherein at least one of the silver-containing targets is sputtered at a power exceeding 12 kW.  
   
   
       25 . The method of  claim 21  wherein the coater includes upward coating equipment comprising lower sputter targets mounted at a lower elevation than the path of substrate travel, the coater having at least a plurality of upward sputtering chambers each including at least one of the lower sputter targets, and wherein the method includes upwardly sputtering at least some of the lower sputtering targets to deposit film on the bottom major surface of the glass sheet.  
   
   
       26 . A method for depositing film onto a sheet-like substrate, the method comprising: 
 a) providing a coater having an extended series of sputtering chambers and a path of substrate travel extending through all the sputtering chambers of the coater, wherein the coater's extended series of sputtering chambers includes at least 60 sputtering chambers at least some of which are adapted for downward sputtering and include upper sputtering targets mounted above the path of substrate travel;    b) conveying the substrate along the path of substrate travel in a generally horizontal orientation wherein a top major surface of the substrate is oriented upwardly and a bottom major surface of the substrate is oriented downwardly, the substrate being conveyed along at least a portion of the path of substrate travel at a conveyance rate exceeding 275 inches per minute; and    c) sputtering two series of the upper targets in nitriding gas to reactively sputter deposit over the top major surface of the substrate two transparent dielectric nitride film regions, wherein an infrared-reflective film region is deposited between said two transparent dielectric nitride film regions, and wherein said two transparent dielectric nitride film regions and said infrared-reflective film region between them are part of a coating comprising, moving outwardly from the top major surface of the substrate, a first transparent dielectric film region, a first infrared-reflective film region comprising silver, a second transparent dielectric film region, a second infrared-reflective film region comprising silver, a third transparent dielectric film region, a third infrared-reflective film region comprising silver, and a fourth transparent dielectric film region.    
   
   
       27 . The method of  claim 26  wherein said reactive sputter deposition of said transparent dielectric nitride film regions results in a combined thickness of at least 100 angstroms for said transparent dielectric nitride film regions.  
   
   
       28 . The method of  claim 27  wherein said combined thickness is at least 150 angstroms.  
   
   
       29 . The method of  claim 26  wherein both of said transparent dielectric nitride film regions comprise silicon nitride.  
   
   
       30 . The method of  claim 26  wherein the coater's extended series of sputtering chambers includes at least 63 sputtering chambers.  
   
   
       31 . The method of  claim 26  wherein during said conveyance of the substrate the method comprises simultaneously sputtering silver in at least three of the sputtering chambers adapted for downward sputtering, said three chambers being separated from one another by other chambers that contain reactive sputtering atmospheres and are adapted for sputter depositing transparent dielectric film.  
   
   
       32 . The method of  claim 31  wherein said simultaneous sputtering of silver involves applying an average power of greater than 9.0 kW on three desired ones of the upper sputtering targets.  
   
   
       33 . A method for depositing film onto a glass sheet, the method comprising: 
 a) providing a coater having an extended series of sputtering chambers and a path of substrate travel extending through all the sputtering chambers of the coater, wherein the coater's extended series of sputtering chambers includes at least 63 sputtering chambers at least some of which are adapted for downward sputtering and include upper sputtering targets mounted above the path of substrate travel;    b) conveying the glass sheet along the path of substrate travel in a generally horizontal orientation wherein a top major surface of the glass sheet is oriented upwardly and a bottom major surface of the glass sheet is oriented downwardly, the glass sheet being conveyed along at least a portion of the path of substrate travel at a conveyance rate of 300 inches per minute or faster; and    c) sputtering two series of the upper targets in nitriding gas to reactively sputter deposit over the top major surface of the substrate two transparent dielectric nitride film regions, wherein an infrared-reflective film region is deposited between said two transparent dielectric nitride film regions, and wherein said two transparent dielectric nitride film regions and said infrared-reflective film region between them are part of a coating comprising, moving outwardly from the top major surface of the substrate, a first transparent dielectric film region, a first infrared-reflective film region comprising silver, a second transparent dielectric film region, a second infrared-reflective film region comprising silver, a third transparent dielectric film region, a third infrared-reflective film region comprising silver, and a fourth transparent dielectric film region;    the method comprising sputter depositing dielectric film directly over at least one of said three infrared-reflective film regions comprising silver.    
   
   
       34 . The method of  claim 33  wherein dielectric film is sputter deposited directly over each of said three infrared-reflective film regions comprising silver.  
   
   
       35 . The method of  claim 33  wherein the dielectric film sputter deposited directly over at least one of said three infrared-reflective film regions is a layer having a thickness of 75 angstroms or less.  
   
   
       36 . The method of  claim 33  wherein the dielectric film sputter deposited directly over at least one of said three infrared-reflective film regions is a layer having a thickness of 50 angstroms or less.