Coater having controllable pressurized process chamber for semiconductor processing

Abstract

A coater having a controllable pressurized process chamber for applying photoresist to a wafer is provided. The controllable pressurized process chamber reduces the evaporation of solvent in the photoresist during a spin-on process step. Reducing premature curing of the photoresist results in improved uniform planarization of the photoresist layer. Contaminants in the photoresist are also reduced by having an environmentally controllable process chamber. A housing having a upper and lower section forms a process chamber surrounding a wafer chuck. The upper housing section includes a solvent vapor opening for introducing pressurized solvent vapor into the process chamber and the lower housing section includes an exhaust opening. The upper housing section also includes an opening for introducing photoresist onto a wafer. A control device is coupled to the exhaust opening and a vacuum device for controlling the pressure in the process chamber. A sealed recycling photoresist container and recycling apparatus is also coupled to the exhaust opening to store unused photoresist. The unused photoresist may be used in subsequent spin-on process steps, thereby reducing processing costs.

1 . A coater for dispensing material on a wafer substrate, comprising: 
 (a) a wafer chuck having a wafer chuck surface for positioning the wafer substrate;    (b) a spin motor, coupled to the wafer chuck, for rotating the wafer chuck;    (c) a housing enclosing the wafer chuck surface and forming a process chamber; and,    (d) a control device, coupled to the housing, for controlling the pressure in the process chamber.    
     
     
         2 . The coater of    claim 1   , wherein the housing includes an upper section having a material dispensing opening and a lower section having an exhaust opening.  
     
     
         3 . The coater of    claim 2   , wherein the lower section is positionable to access the process chamber.  
     
     
         4 . The coater of    claim 2   , wherein an exhaust tube is coupled to exhaust opening and the control device.  
     
     
         5 . The coater of    claim 1   , wherein the control device includes a chamber valve.  
     
     
         6 . The coater of    claim 2   , wherein the housing upper section includes a cavity for containing solvent vapor and a plurality of cavity openings for introducing solvent vapor into the process chamber.  
     
     
         7 . The coater of    claim 2   , wherein the housing lower section includes an opening for introducing nitrogen into the process chamber.  
     
     
         8 . The coater of    claim 1   , further comprising a recycling container, coupled to the control device, for holding unused material from the process chamber.  
     
     
         9 . The coater of    claim 1   , wherein the material is photoresist.  
     
     
         10 . The coater of    claim 1   , wherein the material is viscous material.  
     
     
         11 . The coater of    claim 1   , wherein the material is spin-on-glass.  
     
     
         12 . The coater of    claim 1   , wherein the material is anti-reflection coating.  
     
     
         13 . The coater of    claim 1   , wherein the coater further includes a pressure regulator, coupled to the upper housing, for providing pressurized solvent vapor.  
     
     
         14 . A photoresist coater having a controllable pressurized process chamber, comprising: 
 (a) a wafer chuck having a wafer chuck surface for positioning a wafer to be coated with the photoresist;    (b) a spin motor, coupled to the wafer chuck, for rotating the wafer chuck;    (c) a lower housing section, coupled to the wafer chuck, having an exhaust opening;    (d) an upper housing section, coupled to the lower housing section, forming a process chamber surrounding the wafer chuck surface;    (e) a vacuum, coupled to the lower housing section, for providing a pressure in response to a vacuum control signal;    (f) a control device, coupled to the lower housing section and vacuum device, for controlling the pressure responsive to a control device signal; and,    (g) a pressure regulator, coupled to the upper housing, for providing solvent vapor pressure in the process chamber.    
     
     
         15 . The photoresist coater of    claim 14   , wherein the control device includes a chamber valve.  
     
     
         16 . The photoresist coater of    claim 14   , wherein the upper housing section includes a solvent vapor opening and a vaporizer is coupled to the solvent vapor opening for providing a controllable solvent vapor in the process chamber.  
     
     
         17 . The photoresist coater of    claim 14   , wherein the lower housing is positionable in order to access the process chamber.  
     
     
         18 . The photoresist coater of    claim 14   , wherein the housing upper section includes a cavity for containing solvent vapor and a plurality of cavity openings for introducing solvent vapor into the process chamber.  
     
     
         19 . The photoresist coater of    claim 14   , wherein the housing lower section includes a nitrogen opening for introducing nitrogen into the process chamber.  
     
     
         20 . The photoresist coater of    claim 14   , further comprising a photoresist recycling container, coupled to the control device, for holding unused photoresist from the process chamber.  
     
     
         21 . The photoresist coater of    claim 20   , wherein the photoresist recycling container is coupled to a filter.  
     
     
         22 . A photoresist coater having a controllable pressurized process chamber for spinning photoresist onto a wafer substrate surface, comprising: 
 (a) a wafer chuck having a wafer chuck surface for positioning the wafer substrate;    (b) a spin motor, coupled to the wafer chuck, for rotating the wafer chuck;    (c) a housing, coupled to the wafer chuck, forming a process chamber;    (d) an exhaust tube, coupled to the housing, for exhausting the process chamber;    (e) a photoresist recycling apparatus, coupled to the exhaust tube, for storing unused photoresist from the process chamber.    
     
     
         23 . The photoresist coater of    claim 22   , wherein the photoresist recycling apparatus includes a photoresist container.  
     
     
         24 . The photoresist coater of    claim 23   , wherein the photoresist container is coupled to a control device for sealing the photoresist container.  
     
     
         25 . The photoresist coater of    claim 23   , wherein a vacuum device is coupled to the photoresist container.  
     
     
         26 . The photoresist coater of    claim 22   , wherein the photoresist recycling apparatus includes a collection tube having a baffle coupled to the exhaust tube.  
     
     
         27 . The photoresist recycling apparatus of    claim 26   , wherein the collection tube includes a vacuum port for coupling a vacuum.  
     
     
         28 . The photoresist recycling apparatus of    claim 27   , wherein the collection tube is further coupled to a reservoir for holding unused photoresist.  
     
     
         29 . A process for forming a photoresist layer on a wafer substrate surface in a coater having a controllable pressurized process chamber, comprising the steps of: 
 (a) opening the process chamber;    (b) positioning the wafer substrate on a wafer chuck in the process chamber;    (c) closing the process chamber;    (d) evacuating the process chamber;    (e) introducing a pressurized solvent vapor into the process chamber;    (f) applying the photoresist to the wafer substrate; and,    (g) spinning the wafer chuck.    
     
     
         30 . The process of    claim 29   , further comprising the step of: 
 storing excess photoresist.    
     
     
         31 . The process of    claim 29   , further comprising the step of: 
 storing pressurized excess photoresist.    
     
     
         32 . The process step of    claim 29   , further comprising the steps of: 
 introducing nitrogen into the process chamber.