Plasma Etching Apparatus
The present invention relates to an etching apparatus which is capable of etching the entire surface of a substrate uniformly even if the substrate is large-sized and in which deterioration of etching shape does not occur. An etching apparatus 1 has a chamber 2 having a plasma generating space 9 and a processing space 6, a coil 16 disposed on the outside of a portion corresponding to the plasma generating space 9, a platen 10 which is provided in the processing space 6 and on which a substrate K is to be placed, a processing gas supply mechanism 19 for supplying a processing gas into the plasma generating space 9, an RF power supply mechanism 17 for supplying RF power to the coil 16, and a power supply mechanism for platen 13 for supplying RF power to the platen 10. A cylindrical plasma density adjusting member 20 which is made of a conductive material grounded is fixedly provided on an inner wall of the chamber 2 between the plasma generating space 9 and the platen 10. While plasma passes through the plasma density adjusting member 20, the in-plane density of the plasma is equalized, and then the plasma is guided to the substrate K.
1 . A plasma etching apparatus comprising:
a chamber which comprises a cylindrical body portion, a top plate for closing the top of the body portion, and a bottom plate for closing the bottom of the body portion, and which has a plasma generating space defined in an upper region in the body portion and a processing space defined below the plasma generating space;
a coil disposed on the outside of a portion of the chamber corresponding to the plasma generating space in such manner that it winds around the chamber;
a platen which is disposed in the processing space in the chamber and on which a substrate to be processed is to be placed;
processing gas supply means for supplying a processing gas into the plasma generating space in the chamber;
power supply means for coil for supplying RF power to the coil;
power supply means for platen for supplying RF power to the platen; and
a plasma density adjusting member which comprises a cylindrical member having an opening at the top and an opening at the bottom, and the upper end portion of which is fixed on an inner wall of the chamber between the plasma generating space and the platen, and which adjusts the in-plane density of a plasma generated in the plasma generating space and guides the plasma to a substrate on the platen, characterized in that
the body portion forming the plasma generating space is formed to have an inner diameter larger than the outer dimension of the substrate, and
the plasma density adjusting member is made of a conductive material grounded and is formed in a funnel shape the lower end portion of which has an inner diameter smaller than the inner diameter of the upper end portion thereof and than the inner diameter of the body portion forming the plasma generating space.
2 . The plasma etching apparatus according to claim 1 , wherein the plasma generating space is formed in a doughnut shape by providing at the central portion of the top plate a cylindrical core member which hangs downward from the top plate.
3 . The plasma etching apparatus according to claim 2 , characterized in that the core member is made of a non-conductive material.