Post etch defluorination process
View Patent ↗Defluorination processes for removing fluorine residuals from a workpiece such as a semiconductor wafer are provided. In one example implementation, a method for processing a workpiece can include supporting a workpiece on a workpiece support. The workpiece can have a photoresist layer. The workpiece can have one or more fluorine residuals on a surface of the workpiece. The method can include performing a defluorination process on the workpiece at least in part using a plasma generated from a first process gas. The first process gas can include a hydrogen gas. Subsequent to performing the defluorination process, the method can include performing a plasma strip process on the workpiece to at least partially remove a photoresist layer from the workpiece.
1. A method for processing a workpiece, the method comprising:
supporting a workpiece on a workpiece support, the workpiece having a photoresist layer, the workpiece having one or more fluorine residuals on a surface of the workpiece;
performing a defluorination process on the workpiece at least in part using a plasma generated from a first process gas, the first process gas comprising a hydrogen gas;
subsequent to performing the defluorination process, performing a plasma strip process on the workpiece to at least partially remove the photoresist layer from the workpiece;
wherein the workpiece comprises a metal layer.
2. The method of claim 1 , wherein performing the defluorination process comprises:
generating one or more hydrogen radicals in a plasma chamber from the first process gas using a plasma source;
filtering ions generated using the plasma with a separation grid separating the plasma chamber from a processing chamber;
exposing the workpiece to the hydrogen radicals in the processing chamber.
3. The method of claim 1 , wherein the first process gas further comprises a carrier gas, wherein the carrier gas comprises nitrogen or an inert gas.
4. The method of claim 1 , wherein the plasma strip process comprises:
generating one or more species in a plasma chamber from a second process gas using a plasma source;
filtering ions using a separation grid separating the plasma chamber from a processing chamber to allow the passage of one or more neutral radicals;
exposing the workpiece to one or more neutral radicals in the processing chamber;
wherein the second process gas comprises oxygen.
5. The method of claim 1 , wherein the defluorination process is implemented for a treatment time, the treatment time being in the range of about 5 seconds to about 60 seconds.
6. The method of claim 1 , wherein the defluorination 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.
7. The method of claim 1 , wherein the defluorination process is conducted at a source power, the source power being in the range of about 600 W to about 5000 W.
8. The method of claim 1 , wherein the defluorination process is conducted with the workpiece at a process temperature, the process temperature being in the range of about 90° C. to about 400° C.
9. The method of claim 1 , wherein a ratio of hydrogen gas to one or more carrier gases in the first process gas is about 2 to about 100.
10. The method of claim 1 , wherein the metal layer comprises tungsten.
11. The method of claim 1 , wherein the fluorine residuals result from an etch process.
12. The method of claim 2 , wherein the hydrogen radicals react with the one or more fluorine residuals to generate an HF gas.
13. The method of claim 12 , further comprising pumping the HF gas from the processing chamber prior to performing the plasma strip process.
14. The method of claim 4 , wherein the second process gas comprises oxygen and nitrogen.
15. A method for implementing a defluorination process on a workpiece, the workpiece comprising a photoresist layer, the workpiece having one or more fluorine residuals on the workpiece, the method comprising:
supporting the workpiece on a workpiece support in a processing chamber;
generating one or more hydrogen radicals;
exposing the one or more hydrogen radicals to the workpiece to react the hydrogen radicals with the one or more fluorine residuals and generate an HF gas;
evacuating the HF gas from the processing chamber,
wherein the one or more hydrogen radicals are generated using a tungsten filament.
16. The method of claim 15 , wherein the one or more hydrogen radicals are generated from a process gas using an inductively coupled plasma source.
17. The method of claim 16 , wherein the one or more hydrogen radicals are generated by mixing a hydrogen gas with one or more excited inert gas molecules downstream of a plasma source.
18. The method of claim 17 , wherein the processing chamber is separated from the plasma source by a separation grid, the hydrogen gas being mixed with one or more excided inert gas molecules at or below the separation grid.