Selective etch process using hydrofluoric acid and ozone gases
Systems and methods for etching titanium containing layers on a workpiece are provided. In one example, a method includes placing the workpiece on a workpiece support in a processing chamber. The workpiece includes a first layer and a second layer. The first layer is a titanium containing layer. The method includes admitting a process gas into the processing chamber. The process gas includes an ozone gas and a fluorine containing gas. The method includes exposing the first layer and the second layer on the workpiece to the process gas to at least partially etch the first layer at a greater etch rate relative to the second layer.
1. A method for processing a workpiece, the method comprising:
placing the workpiece on a workpiece support in a processing chamber, the workpiece comprising a first layer and a second layer, the first layer being a titanium nitride layer;
admitting a process gas into a plasma chamber, the plasma chamber being separated from the processing chamber by a separation grid, the first process gas comprising a fluorine containing gas and a hydrogen containing gas;
generating HF radicals by generating a plasma in the process gas in the plasma chamber;
delivering HF radicals through the separation grid to the processing chamber to be exposed to the workpiece;
injecting ozone gas into the HF radicals passing through the separation grid at a location downstream of the plasma such that there is a co-flow of HF radicals and ozone gas into the processing chamber; and
exposing the first layer and the second layer on the workpiece to the co-flow of HF radicals and ozone gas to at least partially etch the first layer at a greater etch rate relative to the second layer.
2. The method of claim 1 , wherein the second layer is a silicon layer or a silicon germanium layer.
3. The method of claim 1 , wherein the second layer is a metal layer.
4. The method of claim 1 , wherein the second layer is silicon nitride or silicon dioxide layer.
5. The method of claim 1 , wherein the ozone gas comprises an oxygen gas.
6. The method of claim 1 , wherein the process gas comprises a carrier gas, wherein the carrier gas comprises on or more of nitrogen, helium, argon, or neon.
7. The method of claim 1 , wherein the ozone gas is admitted through one or more gas injection ports into the separation grid.
8. The method of claim 1 , wherein the ozone gas is admitted from a gas injection port located in the processing chamber.