Object-processing apparatus controlling production of particles in electric field or magnetic field

An apparatus, comprising:

• a housing defining a chamber having a gas inlet and outlet in which an electric field is generated by upper and lower electrodes;
• and an internal ring-shaped member provided in said chamber, wherein at least one part of said internal ring-shaped member, every sidewall portion of the chamber, and said gas inlet and outlet are formed of a first dielectric material,
• wherein said electric field causes formation of a second dielectric deposit on the first dielectric material on the at least one part of said internal ring-shaped member including the sidewall portions, such that an m1(d∈1/dm1) value of said first dielectric material and an m2(d∈2/dm2) value of said second dielectric deposit are different from each other and are set so that production of particles from said second dielectric deposit is controlled, m1 being a mass density of said first dielectric material, ∈1 being a permittivity of said first dielectric material, m2 being a mass density of said second dielectric deposit, and ∈2 being a permittivity of said second dielectric deposit,
• wherein the internal ring-shaped member is provided to position a wafer on the lower electrode or is provided surrounding the upper electrode.