Method and apparatus for heating a wafer, and method and apparatus for baking a photoresist film on a wafer

Abstract

To heat an object, a first solid heat transfer medium is supplied with heat. The heat is transmitted from the first solid heat transfer medium to a fluid heat transfer medium which is partitioned into an interconnected plurality of evaporation cavities each containing a liquid. The heat causes the liquid to evaporate into a plurality of vapor parts in the respective plurality of evaporation cavities, and the plurality of vapor parts are guided in parallel in an upward direction towards the object. The vapor parts contact a second solid heat transfer medium to heat the second solid heat transfer medium, thereby transmitting the heat to the second solid heat transfer medium. The second solid heat transfer medium is thermally contacted with the object to transmit the heat from the second solid heat transfer medium to the object.

What is claimed is:  
     
         1 . A method for uniformly heating an object, comprising: 
 supplying a first solid heat transfer medium with heat;    transmitting the heat from the first solid heat transfer medium to a fluid heat transfer medium which is partitioned into an interconnected plurality of evaporation cavities each containing a liquid, wherein the heat causes the liquid to evaporate into a plurality of vapor parts in the respective plurality of evaporation cavities, and wherein the plurality of vapor parts are guided in parallel in an upward direction towards the object;    contacting the vapor parts with a second solid heat transfer medium to heat the second solid heat transfer medium, thereby transmitting the heat to the second solid heat transfer medium; and    thermally contacting the second solid heat transfer medium with the object to transmit the heat from the second solid heat transfer medium to the object.    
     
     
         2 . The method for heating an object as claimed in  claim 1 , further comprising: 
 generating the heat;    transmitting the heat to a lower solid heat transfer medium to heat the lower solid heat transfer medium; and    thermally contacting the lower solid heat transfer medium with the first solid heat transfer medium to transmit the heat to the first solid heat transfer medium.    
     
     
         3 . The method for heating an object as claimed in  claim 1 , wherein an upper portion of each of the plurality of evaporation cavities has a curved cross-sectional configuration, and wherein the plurality of vapor parts contact the second solid heat transfer medium at the upper portion of the respective plurality of evaporation cavities.  
     
     
         4 . The method for heating an object as claimed in  claim 3 , wherein the plurality of vapor parts partially condense to generate a latent heat which is transmitted to the second solid heat transfer medium.  
     
     
         5 . The method for heating an object as claimed in  claim 1 , further comprising condensing the plurality of vapor parts to reform the liquid, wherein the liquid is repeatedly evaporated into the vapor parts and the vapor parts are repeatedly condensed into the liquid so as to circulate within each the evaporation cavities of the fluid heat transfer medium.  
     
     
         6 . The method for heating an object as claimed in  claim 1 , wherein each of the vapor parts is partially mixed with a vapor part contained in an adjacent evaporation cavity of the fluid heat transfer medium while being guided toward the object.  
     
     
         7 . The method for heating an object as claimed in  claim 6 , wherein the fluid heat transfer medium has a circular outer periphery, and wherein each of the vapor parts is mixed with a vapor part contained in a radially or circularly adjacent evaporation cavity.  
     
     
         8 . The method for heating an object as claimed in  claim 1 , wherein the fluid heat transfer medium has a circular outer periphery, and wherein the plurality of evaporation cavities are partitioned into a plurality of concentric or spiral circles which are divided into a plurality of radial sectors.  
     
     
         9 . The method for heating an object as claimed in  claim 8 , wherein a sector angle of each of the plurality of radial sectors is about 10 to 20 degrees.  
     
     
         10 . The method for heating an object as claimed in  claim 1 , wherein the object is a photoresist film coated on a wafer.  
     
     
         11 . The method for heating an object as claimed in  claim 1 , wherein the liquid is an inert perfluorocabon-type solvent which has a higher critical temperature under an atmosphere than the sum of a target temperature for the object plus 100° C.  
     
     
         12 . A method for baking a photoresist film on a wafer, comprising: 
 coating a photoresist solution on a wafer to form the photoresist film;    exposing the photoresist film to a light;    supplying a first solid heat transfer medium with heat;    transmitting the heat from the first solid heat transfer medium to a fluid heat transfer medium which is partitioned into an interconnected plurality of evaporation cavities each containing a liquid, wherein the heat causes the liquid to evaporate into a plurality of vapor parts in the respective plurality of evaporation cavities, and wherein the plurality of vapor parts are guided in parallel in an upward direction towards the wafer;    contacting the vapor parts with a second solid heat transfer medium to heat the second solid heat transfer medium, thereby transmitting the heat to the second solid heat transfer medium; and    thermally contacting the second solid heat transfer medium with the wafer to transmit the heat from the second solid heat transfer medium to the wafer, thereby baking the photoresist film on the wafer.    
     
     
         13 . The method for baking a photoresist film on a wafer as claimed in  claim 12 , wherein the light is a deep ultraviolet light.  
     
     
         14 . The method for baking a photoresist film on a wafer as claimed in  claim 12 , wherein the photoresist film is baked at a temperature of about 140 to 150° C. for 0.5 to 1.5 minutes.  
     
     
         15 . A method for forming a photoresist pattern, comprising coating a photoresist solution on a wafer to form a photoresist film, exposing the photoresist film to a light, developing the exposed photoresist film to form a first photoresist pattern having a first opening of a first size, and reflowing the first photoresist pattern to form a second photoresist pattern having a second opening of a second size which is smaller than the first size, wherein said reflowing of the first photoresist pattern comprises: 
 supplying a first solid heat transfer medium with heat;    transmitting the heat from the first solid heat transfer medium to a fluid heat transfer medium which is partitioned into an interconnected plurality of evaporation cavities each containing a liquid, wherein the heat causes the liquid to evaporate into a plurality of vapor parts in the respective plurality of evaporation cavities, and wherein the plurality of vapor parts are guided in parallel in an upward direction towards the wafer;    contacting the vapor parts with a second solid heat transfer medium to heat the second solid heat transfer medium, thereby transmitting the heat to the second solid heat transfer medium; and    thermally contacting the second solid heat transfer medium with the wafer to transmit the heat from the second solid heat transfer medium to the wafer, whereby the first photoresist pattern is heated to reflow.    
     
     
         16 . An apparatus for heating an object, said apparatus comprising: 
 a first solid heat transfer medium;    a fluid heat transfer medium, thermally coupled to the first solid heat transfer medium, which is partitioned into an interconnected plurality evaporation cavities;    a second solid heat transfer medium, thermally coupled to the fluid heat transfer medium, for making thermal contact with the object;    wherein the plurality of evaporation cavities extend in a same plane between the first and second solid heat transfer mediums.    
     
     
         17 . An apparatus for heating an object as claimed in  claim 16 , further comprising a liquid sealed within the plurality of evaporation cavities of the fluid heat transfer medium.  
     
     
         18 . The apparatus for heating an object as claimed in  claim 16 , further comprising a heating element, and a lower solid heat transfer medium thermally coupled between the heating element and the first solid heat transfer medium.  
     
     
         19 . The apparatus for heating an object as claimed in  claim 18 , wherein the heating element is at least partially contained in a groove formed at a lower surface of the lower solid heat transfer medium.  
     
     
         20 . The apparatus for heating an object as claimed in  claim 19 , wherein the groove has a spiral configuration, and wherein a pitch of the spiral configuration is shorter at an outer peripheral region than at a central region of the lower surface portion.  
     
     
         21 . The apparatus for heating an object as claimed in  claim 16 , wherein said second solid heat transfer medium is integrally formed with said first solid heat transfer medium.  
     
     
         22 . The apparatus for heating an object as claimed in  claim 16 , wherein the first and second solid heat transfer media and the fluid heat transfer medium each have a circular and planar configuration.  
     
     
         23 . The apparatus for heating an object as claimed in  claim 22 , wherein a diameter of the fluid heat transfer medium is equal to about 0.9 to 0.98 times a diameter of the first and second solid heat transfer media.  
     
     
         24 . The apparatus for heating an object as claimed in  claim 22 , wherein the fluid heat transfer medium has a circular outer periphery, and wherein the plurality of evaporation cavities are partitioned into a plurality of concentric or spiral circles which are divided into a plurality of radial sectors.  
     
     
         25 . The apparatus for heating an object as claimed in  claim 17 , wherein an occupied volume of the liquid within the fluid heat transfer medium is about 15 to 25% of a volume of fluid heat transfer medium.  
     
     
         26 . The apparatus for heating an object as claimed in  claim 16 , wherein a thickness of the fluid heat transfer medium is about 40% to 60% of a combined thickness of the first and second solid heat transfer media and the fluid heat transfer medium.  
     
     
         27 . The apparatus for heating an object as claimed in  claim 17 , wherein said fluid is an inert perfluorocabon-type solvent which has a higher critical temperature under an atmosphere than the sum of an object target temperature plus 100° C.  
     
     
         28 . An apparatus for heating a wafer, said apparatus comprising: 
 a heating element;    a lower solid heat transfer medium thermally coupled to the heating element;    a first solid heat transfer medium thermally coupled to an upper surface of the lower solid heat medium;    a second solid heat transfer medium having a wafer mounting surface and thermally coupled to said first solid heat transfer medium opposite said wafer mounting surface;    a fluid heat transfer medium defined by a plurality of interconnected evaporation cavities interposed between said first and second solid heat transfer media.    
     
     
         29 . The apparatus for heating a wafer as claimed in  claim 28 , wherein the plurality of evaporation cavities are partitioned into a plurality of concentric or spiral circles which are radially divided into a plurality of radial sectors.  
     
     
         30 . The apparatus for heating a wafer as claimed in  claim 29 , further comprising a liquid sealed within the plurality of evaporation cavities.  
     
     
         31 . The apparatus for heating a wafer as claimed in  claim 29 , wherein the first and second solid heat transfer media are circular and have a diameter which is greater than a diameter of the wafer mounting surface.  
     
     
         32 . The apparatus for heating a wafer as claimed in  claim 31 , wherein the first and second solid heat transfer media are integrally formed.  
     
     
         33 . The apparatus for heating a wafer as claimed in  claim 28 , wherein the heating element is located in a spiral groove formed in a lower surface of the lower solid heat transfer medium.  
     
     
         34 . The method for heating an object as claimed in  claim 28 , wherein an upper portion of each of the plurality of evaporation cavities has a curved cross-sectional configuration.