Plasma processing apparatus and method of plasma distribution correction
A plasma processing apparatus can prevent a sheath from becoming distorted, simplify a configuration of the apparatus, and prevent particles from attaching to a substrate. The plasma processing apparatus performs plasma processing on the substrate. A housing chamber houses the substrate. A mounting stage is disposed within the housing chamber and mounted with the substrate. An annular member is disposed in the mounting stage. A power supply unit supplies high-frequency power to the mounting stage. An observation unit optically observes the distribution of the plasma. A voltage applying unit applies a DC voltage to the annular member. A control unit sets the value of the DC voltage to be applied based on the observed plasma distribution.
1. A plasma processing apparatus provided with a housing chamber adapted to house a substrate; a mounting stage disposed within said housing chamber and mounted with said substrate; an annular member disposed in said mounting stage so as to surround the periphery of said mounted substrate; and a power supply unit adapted to supply high-frequency power to said mounting stage; and configured to perform a plasma processing on said substrate using plasma produced within said housing chamber, said plasma processing apparatus comprising:
an observation unit adapted to optically observe the plasma sheath distorted over the annular member;
a voltage applying unit adapted to apply a negative DC voltage to said annular member; and
a control unit adapted to cause said voltage applying unit to apply said negative DC voltage to said annular member so as to remove distortion of sheath over the substrate and annular member,
the control unit adapted further to lower the value of high-frequency power to be supplied to said mounting stage which is a member other than said annular member on the basis of observed sheath thickness after application of negative DC voltage to the annular part,
wherein said voltage applying unit includes a screw member connecting said annular member and said mounting stage and applies said negative DC voltage to said annular member through said mounting stage and said screw member.
2. The plasma processing apparatus according to claim 1 , wherein said control unit sets the value of said negative DC voltage to be applied, so as to increase a potential difference between said annular member and said plasma.
3. The plasma processing apparatus according to claim 1 , wherein said power supply unit is connected to said mounting stage through a power supply rod and said voltage applying unit applies said negative DC voltage to said annular member through said power supply rod and said mounting stage.
4. The plasma processing apparatus according to claim 1 , wherein said voltage applying unit includes a conductive wire in contact with said annular member and applies said negative DC voltage to said annular member through said conductive wire.
5. The plasma processing apparatus according to claim 1 , wherein said observation unit is a CCD camera.