System and method for monitoring treatment of microelectronic substrates with fluid sprays such as cryogenic fluid sprays

Abstract

Techniques herein pertain to apparatus embodiments and methods for treating the surface of a microelectronic substrate, and in particular for removing objects from the microelectronic substrate using fluid treatment sprays such as cryogenic fluid sprays. The apparatus embodiments and methods described herein further include techniques for monitoring and/or controlling treatment processes for removing particles from surfaces of a microelectronic substrate. The techniques allow using image analysis techniques to monitor characteristics of spray nozzle(s) (e.g., frost formation on the nozzle surface) and using the resultant image information of the nozzle to take corrective action if frost or another nozzle condition is detected.

1 - 21 . (canceled) 
     
     
         22 . A method for treating a substrate, comprising:
 (a) dispensing a fluid treatment medium through at least one nozzle onto a microelectronic substrate positioned in a process chamber;   (b) illuminating the at least one nozzle with light comprising at least of one or more of visible light, ultraviolet light, and infrared light;   (c) using an image capture device to capture image data of the at least one illuminated nozzle;   (d) storing the image data in a memory; and   (e) analyzing the image data using a computer processor to determine whether frost is on the at least one nozzle.   
     
     
         23 . The method of  claim 22 , wherein step (b) comprises illuminating the at least one nozzle through a window. 
     
     
         24 . The method of  claim 22 , wherein step (b) comprises illuminating the at least one nozzle with light comprising white light. 
     
     
         25 . The method of  claim 22 , wherein step (b) comprising illuminating the at least one nozzle with one or more of the visible light, ultraviolet light, and infrared light that is controlled to be within one or more selected wavelength bands, wherein the wavelength bands have bandwidths in the range from 20 nm to 200 nm wide. 
     
     
         26 . The method of  claim 25 , wherein a selected wavelength band comprises infrared light. 
     
     
         27 . The method of  claim 25 , wherein a selected wavelength band comprises visible light. 
     
     
         28 . The method of  claim 25 , wherein step c) comprises capturing image information for at least 4 cm 2  of the at least one nozzle. 
     
     
         29 . The method of  claim 22 , wherein the at least one nozzle comprises a polished surface. 
     
     
         30 . The method of  claim 22 , wherein the at least one nozzle comprises a polished stainless steel surface. 
     
     
         31 . The method of  claim 22 , wherein the illuminated, at least one nozzle scatters light, and wherein step (e) comprises using the computer processor to carry out program instructions to evaluate the scattered light. 
     
     
         32 . The method of  claim 22 , wherein the illuminated, at least one nozzle reflects light, and wherein step (e) comprises using the computer processor to carry out program instructions to evaluate the reflected light. 
     
     
         33 . The method of  claim 22 , wherein step (c) comprises capturing a temporal sequence of optical images of the at least one nozzle. 
     
     
         34 . The method of  claim 22 , further comprising the step of using a controller to adjust at least one process condition for treating the microelectronic substrate in response to information comprising the analysis of step (e). 
     
     
         35 . The method of  claim 22 , wherein step (a) comprises supplying the fluid treatment medium to the at least one nozzle at a temperature greater than or equal to 70 K and less than or equal to 120 K. 
     
     
         36 . The method of  claim 22 , wherein step (a) comprises maintaining the process chamber at a chamber pressure of 35 Torr or less during at least a portion of a time period during which the fluid treatment is dispensed. 
     
     
         37 . The method of  claim 36 , wherein the chamber pressure is maintained at 10 Torr or less. 
     
     
         38 . The method of  claim 22 , wherein step (a) comprises maintaining the process chamber under a vacuum relative to ambient pressure. 
     
     
         39 . The method of  claim 22 , wherein the fluid treatment medium as supplied to the at least one nozzle is pressurized and cooled. 
     
     
         40 . The method of  claim 22 , wherein the at least one nozzle comprises a surface that is specularly reflective when frost-free and that is diffusely reflective when the surface is frosted. 
     
     
         41 . A method for treating a substrate, comprising:
 (a) dispensing a fluid treatment medium through at least one nozzle onto a microelectronic substrate positioned in a process chamber;   (b) illuminating the at least one nozzle with light comprising at least one or more of visible light, ultraviolet light, and infrared light;   (c) using an image capture device to capture image data of the at least one illuminated nozzle; and   (e) analyzing information comprising the image data to determine whether frost is on the at least one nozzle.