LENS OFFSET
This disclosure relates a system and techniques for adjusting component parts of a Plasma-enhanced processing system. The electric field uniformity generated by plasma processing may be improved by adjusting the distance between a cavity of an upper electrode and an insulating plate that covers, at least a portion of, the cavity. In another embodiment, the electric field uniformity may be improved by adjusting the distance between the substrate and the upper electrode.
1 . A plasma reactor, comprising:
a first metal electrode comprising a concave portion that is covered by an insulating plate that is offset from the concave portion of the first metal electrode by an offset distance;
a second metal electrode disposed across from the first metal electrode with the insulating plate facing the second metal electrode; and
a Radio Frequency (RF) source configured to provide power to ionize molecules between the insulating plate and the second metal electrode.
2 . The plasma reactor of claim 1 , wherein the concave portion comprises a dielectric material between the first metal electrode and the insulating plate.
3 . The plasma reactor of claim 2 , wherein the dielectric material is in flush contact with the concave portion and the insulating plate.
4 . The plasma reactor of claim 1 , further comprising a vacuum gap between the concave portion and the insulating plate.
5 . The plasma reactor of claim 4 , wherein the vacuum gap can maintain a pressure less than atmospheric pressure.
6 . The plasma reactor of claim 1 , wherein the insulating plate is offset from the first metal electrode by an offset distance that is based, at least in part, on one or more of the following: an applied frequency of the RF source, a size of the first metal electrode, or a distance between the insulating plate and the second metal electrode.
7 . The plasma reactor of claim 1 , wherein the offset distance comprises a distance less than or equal to 3 mm.
8 . A device, comprising:
a metal electrode comprising a concave portion that extends from a perimeter of the metal electrode to a high point near or along a center line of the metal electrode; and
a non-conductive plate that is substantially planar and covers the concave portion, the non-conductive plate being offset from an outer perimeter of the concave portion by an offset distance.
9 . The device of claim 8 , wherein the concave portion comprises a dielectric material between the metal electrode and the non-conductive plate, and the offset distance comprises a range of about 3 mm to 30 mm.
10 . The device of claim 8 , wherein the concave portion and the non-conductive plate are coupled together to comprise a cavity that can maintain a pressure less than atmospheric pressure.
11 . The device of claim 8 , wherein the concave portion comprises a concavity that is based, at least in part, on a magnitude of the offset distance.
12 . The device of claim 8 , wherein the offset distance comprises a range of about 0.3 mm to about 2 mm.
13 . The device of claim 8 , wherein the metal electrode is a first metal electrode and further comprising a second metal electrode disposed subjacent to the non-conductive plate of the first metal electrode.
14 . The device of claim 8 , wherein the offset distance is based, at least in part, on a frequency of power applied to the metal electrode and a size of the metal electrode.
15 . A system, comprising:
a first conductive electrode comprising:
a concave portion with a concavity that defines the slope profile of the concave portion; and
an insulating plate that covers the concave portion and is on the same plane as an open end of the concave portion;
a second conductive electrode disposed across from the first conductive electrode; and
a substrate spacer component protruding from the second conductive electrode to support a substrate at an offset distance from the second conductive electrode, the offset distance having magnitude that is based, at least in part, on the concavity of the concave portion.
16 . The system of claim 15 , wherein the concave portion comprises a dielectric material between the first conductive electrode and the insulating plate.
17 . The system of claim 15 , wherein the concave portion and the insulating plate are coupled together to comprise a cavity that can maintain a pressure less than atmospheric pressure.
18 . The system of claim 15 , wherein the concavity monotonically decreases along at least a portion of the first conductive electrode between a central region of the concave portion to a peripheral region of the concave portion.
19 . The system of claim 15 , wherein the insulating plate is offset from the first conductive electrode by an offset distance that is based, at least in part, on a frequency of power applied to the first conductive electrode or the second conductive electrode, a size of the first conductive electrode, and a distance between the insulating plate and the second conductive electrode.
20 . The system of claim 15 , further comprising a Radio Frequency power source that provides alternating power to ionize molecules between the first conductive electrode and the second conductive electrode.