Processing method to dissipate fluid accumulation on a spinning wafer

A method for processing a wafer, the method comprising:

• receiving the wafer on a wafer holder disposed in a processing chamber comprising a nozzle, the nozzle disposed over the wafer at a nozzle height, the wafer comprising a wafer radius;
• processing the wafer using a first set of processing parameters during a processing time, the processing comprising rotating the wafer at a first angular velocity and flowing a processing solution over the wafer at a first flow rate, the first set of processing parameters comprising the first angular velocity and the first flow rate;
• during the processing time, determining whether the processing solution has formed a fluid accumulation at a radial distance less than the wafer radius using a light detector;
• and
• in response to determining the processing solution has formed a fluid accumulation at a radial distance less than the wafer radius, accelerating the wafer from the first set of processing parameters to a second set of processing parameters during the processing time, the second set of processing parameters comprising a second angular velocity different from the first angular velocity and a second flow rate different from the first flow rate.

A system for processing a wafer, the system comprising:

• a wafer holder disposed in a processing chamber, the processing chamber comprising a first window and a second window;
• a nozzle disposed at a configurable height over the wafer holder in the processing chamber;
• a light source and a light detector, the light source coupled to the first window and the light detector coupled to the second window;
• a rotary drive coupled to the wafer holder;
• and
• a controller coupled to the nozzle, the processing chamber, the light source, the light detector, the rotary drive, the wafer holder, and a memory storing instructions to be executed in the controller, the instructions when executed enable the controller to:
• receive the wafer on the wafer holder, the nozzle disposed over the wafer at a nozzle height, the wafer comprising a wafer radius;
• process the wafer using a first set of processing parameters during a processing time in the processing chamber, the processing comprising rotating the wafer at a first angular velocity using the rotary drive and flowing a processing solution from the nozzle over the wafer at a first flow rate, the first set of processing parameters comprising the first angular velocity and the first flow rate;
• during the processing time, determine whether the processing solution has formed a fluid accumulation at a radial distance less than the wafer radius using the light detector;
• and
• in response to determining the processing solution has formed a fluid accumulation at a radial distance less than the wafer radius, accelerate the wafer from the first set of processing parameters to a second set of processing parameters during the processing time using the nozzle and the rotary drive, the second set of processing parameters comprising a second angular velocity different from the first angular velocity and a second flow rate different from the first flow rate.