Apparatus and methods for removing contaminant particles in a plasma process

An apparatus for performing a plasma process, comprising:

• a processor;
• and
• a memory storing computer program code configured to, with the processor, cause the apparatus to:
• perform a plasma process at a process pressure and a process power to generate plasma in a plasma processing chamber;
• ramp down the process power and the process pressure substantially simultaneously to an intermediate power level and an intermediate pressure level, respectively, wherein the intermediate power level and the intermediate pressure level are selected so as to raise a plasma sheath boundary above a threshold height from a surface of a substrate;
• maintain the intermediate power level for a first time period and maintain the intermediate pressure level for a second time period while flowing a purge gas from a showerhead assembly;
• and
• reduce the intermediate power level and the intermediate pressure level to a zero power level and a base pressure, respectively.

An apparatus for performing a plasma process, comprising:

• a processor;
• and
• a memory storing computer program code configured to, with the processor, cause the apparatus to:
• perform a plasma process at a process pressure and a process power to generate plasma in a plasma processing chamber;
• select an intermediate power level and an intermediate pressure level;
• ramp down the process power and the process pressure substantially simultaneously to the intermediate power level and the intermediate pressure level, respectively;
• maintain the intermediate power level for a first time period and maintain the intermediate pressure level for a second time period while flowing a purge gas from a showerhead assembly;
• and
• reduce the intermediate power level and the intermediate pressure level.

A non-transitory computer-readable medium comprising software that, when executed, causes a system to:

• perform a plasma process at a process pressure and a process power to generate plasma in a plasma processing chamber;
• ramp down the process power and the process pressure substantially simultaneously to an intermediate power level and an intermediate pressure level, respectively, wherein the intermediate power level and the intermediate pressure level are selected so as to raise a plasma sheath boundary above a threshold height from a surface of a substrate;
• maintain the intermediate power level for a first time period and maintain the intermediate pressure level for a second time period while flowing a purge gas from a showerhead assembly;
• and
• reduce the intermediate power level and the intermediate pressure level to a zero power level and a base pressure, respectively.