Water Vapor Based Fluorine Containing Plasma For Removal Of Hardmask
Apparatus, systems, and methods for conducting a hardmask (e.g., boron doped amorphous carbon hardmask) removal process on a workpiece are provided. In one example implementation, a method includes supporting a workpiece on a workpiece support in a processing chamber. The method can include generating a plasma from a process gas in a plasma chamber using a plasma source. The plasma chamber can be separated from the processing chamber by a separation grid. The method can include exposing the workpiece to one or more radicals generated in the plasma to perform a plasma strip process on the workpiece to at least partially remove the hardmask layer from the workpiece. The method can include exposing the workpiece to water vapor as a passivation agent during the plasma strip process.
1 . A method for processing a workpiece, the method comprising:
supporting a workpiece on a workpiece support in a processing chamber, the workpiece comprising a hardmask layer;
generating a plasma from a process gas in a plasma chamber using a plasma source, the process gas comprising a fluorine containing gas;
exposing the workpiece to one or more radicals generated in the plasma to perform a plasma strip process on the workpiece to at least partially remove the hardmask layer from the workpiece; and
exposing the workpiece to water vapor as a passivation agent during the plasma strip process.
2 . The method of claim 1 , wherein the workpiece comprises one or more silicon dioxide layers and one or more silicon nitride layers.
3 . The method of claim 1 , wherein the plasma chamber is separated from the processing chamber by a separation grid.
4 . The method of claim 1 , wherein exposing the workpiece to water vapor as a passivation agent comprises introducing water vapor into the plasma chamber as part of the process gas.
5 . The method of claim 1 , wherein the fluorine containing gas comprises CF 4 .
6 . The method of claim 1 , wherein the fluorine containing gas comprises CH 2 F 2 .
7 . The method of claim 1 , wherein the fluorine containing gas comprises CH 3 F.
8 . The method of claim 1 , wherein the process gas comprises an oxygen gas.
9 . The method of claim 1 , wherein the process gas comprises a nitrogen gas.
10 . The method of claim 1 , wherein the process gas comprises a hydrogen gas.
11 . The method of claim 1 , wherein the hardmask is a boron doped amorphous hardmask.
12 . The method of claim 1 , wherein the hardmask is a titanium nitride hardmask.
13 . The method of claim 1 , wherein the workpiece comprises a substrate layer.
14 . The method of claim 13 , wherein the substrate layer comprises tungsten.
15 . The method of claim 1 , wherein the plasma strip process is implemented for a process period, the process period being in a range of about 30 seconds to about 1200 seconds.
16 . The method of claim 1 , wherein the plasma strip process is conducted at a process pressure in the processing chamber, the process pressure being in the range of about 300 mT to about 4000 mT.
17 . The method of claim 1 , wherein the plasma strip is conducted at a source power for an inductively coupled plasma source, the source power being in the range of about 600W to about 5000W.
18 . The method of claim 1 , wherein the plasma strip process is conducted with the workpiece at a process temperature, the process temperature being in a range of about 25° C. to about 400° C.
19 . The method of claim 1 , wherein exposing the workpiece to water vapor as a passivation agent comprises introducing water vapor into the processing chamber.
20 . The method of claim 3 , wherein exposing the workpiece to water vapor as a passivation agent comprises introducing water vapor into the processing chamber at a location beneath the separation grid.
21 . The method of claim 3 , wherein exposing the workpiece to water vapor as a passivation agent comprises introducing water vapor into the processing chamber at a location between a first grid plate and a second grid plate of the separation grid.
22 . The method of claim 1 , wherein an ash rate of the plasma strip process is about 1500 Angstroms/minute or more.
23 . A plasma processing apparatus, comprising:
a processing chamber having a workpiece support, the workpiece support configured to support a workpiece during plasma processing;
a plasma chamber separated from the processing chamber by a separation grid;
an inductively coupled plasma source configured to induce a plasma in a process gas in the plasma chamber; wherein radicals generated in the plasma pass through the separation grid for exposure to the workpiece during plasma processing;
a water vapor feed line operable to deliver water vapor to one or more of the plasma chamber, the separation grid, and the processing chamber;
wherein the water vapor feed line comprises a temperature regulation system configured to reduce condensation along a delivery path of water vapor from the water vapor feed line.
24 . The plasma processing apparatus of claim 23 , wherein the temperature regulation system comprises a heat source.