Processing of workpieces using deposition process and etch process
Apparatus, systems, and methods for conducting an etch removal process on a workpiece are provided. The method can include generating a plasma from a deposition process gas in a plasma chamber using a plasma source to deposit a passivation layer on certain layers of a high aspect ratio structure. The method can include generating a plasma from an etch process gas in a plasma chamber using a plasma source to remove certain layers from the high aspect ratio structure. The method can include removing silicon nitride layers at a faster etch rate than silicon dioxide layers on the high aspect ratio structure.
1. A method for processing a workpiece, the workpiece comprising a high aspect ratio structure, the high aspect ratio structure comprising a plurality of silicon nitride layers and a plurality of silicon dioxide layers arranged in an alternating fashion, the method comprising:
placing a workpiece on a workpiece support in a processing chamber;
performing a deposition process to deposit a passivation layer on a surface of at least one of the plurality of silicon dioxide layers, wherein the deposition process comprises:
flowing CF 4 at a flow rate of about 20 sccm to about 200 sccm, CH 4 at a flow rate of about 20 sccm to about 200 sccm, O 2 at a flows rate of about 500 sccm to about 1500 sccm, and N 2 at a flow rate of about 100 sccm to about 500 sccm into a plasma chamber to form a deposition process gas;
generating one or more species from the deposition process gas using a plasma induced in a plasma chamber; and
exposing the workpiece to the one or more species generated from the deposition process gas to deposit the passivation layer, wherein the passivation layer comprises a fluorocarbon polymer, a hydrofluorocarbon polymer, a slat ammonium silicon fluoride salt, or a combination thereof; and
performing an etch process to remove at least a portion of the plurality of silicon nitride layers laterally at an etch rate that is greater than an etch rate of the plurality of silicon dioxide layers.
2. The method of claim 1 , further comprising cyclically alternating the deposition process and the etch process.
3. The method of claim 1 , wherein a ratio of etch rate of the plurality of silicon nitride layers to the etch rate of the plurality of silicon dioxide layers is greater than about 500.
4. The method of claim 1 , wherein performing the deposition process to deposit the passivation layer on the plurality of silicon dioxide layers comprises:
filtering the one or more species to generate a filtered deposition mixture; and
exposing the plurality of silicon dioxide layers to the filtered deposition mixture.
5. The method of claim 4 , wherein filtering the one or more species to generate a filtered deposition mixture comprises filtering the one or more species via a separation grid separating the plasma chamber from the processing chamber.
6. The method of claim 5 , further comprising the step of admitting a non-process gas through one or more gas injection ports at or below the separation grid to adjust energy of radicals passing through the separation grid.
7. The method of claim 1 , wherein performing the etch process to remove at least a portion of the plurality of silicon nitride layers laterally at an etch rate that is greater than an etch rate of the plurality of silicon dioxide layers comprises:
generating one or more species from an etch process gas using a plasma induced in a plasma chamber, wherein the plasma is induced by via an inductively coupled plasma source;
filtering the one or more species to generate a filtered etching mixture; and
exposing the plurality of silicon nitride layers to the filtered etching mixture to remove at least a portion of the plurality of silicon nitride layers laterally at an etch rate that is greater than an etch rate of the plurality of silicon dioxide layers.
8. The method of claim 7 , wherein filtering the one or more species to generate a filtered etching mixture comprises filtering the one or more species via the separation grid separating the plasma chamber from the processing chamber.
9. The method of claim 8 , further comprising the step of admitting a non-process gas through one or more gas injection ports at or below the separation grid to adjust energy of radicals passing through the separation grid.
10. The method of claim 7 , wherein the etch process gas comprises a fluorine containing gas comprising tetrafluoromethane (CF 4 ), difluoromethane (CH 2 F 2 ), fluoromethane (CH 3 F), fluoroform (CHF 3 ), or tetrafluoroethylene (C 2 F 4 ).
11. The method of claim 7 , wherein the etch process gas comprises hydrogen containing gas comprising hydrogen (Hz), methane (CH 4 ), or ammonia (NH 3 ).
12. The method of claim 7 , wherein the etch process gas comprises an oxygen containing gas comprising oxygen (O 2 ), nitric oxide (NO), or carbon dioxide (CO 2 ).
13. The method of claim 1 , further comprising performing a cleaning process after the deposition process and before the etch process.
14. The method of claim 13 , wherein the cleaning process comprises exposing the processing chamber to a purging gas, wherein the purging gas comprises H 2 or O 2 .
15. The method of claim 1 , further comprising a residual removal process to remove residual passivation layer on the structure, the residual removal process comprising:
generating one or more species from a second etch process gas using a plasma induced in a plasma chamber;
filtering the one or more species to generate a filtered second etching mixture; and
exposing the plurality of silicon nitride layers and silicon dioxide layers to the filtered second etching mixture in the processing chamber, wherein the second etching mixture removes any remaining passivation layer from the workpiece.
16. A method for processing a workpiece, the workpiece comprising a high aspect ratio structure, the high aspect ratio structure comprising a plurality of silicon nitride layers and a plurality of silicon dioxide layers arranged in an alternating fashion, the method comprising:
placing the workpiece in a processing chamber, the processing chamber located downstream from a plasma chamber for generating a plasma, wherein the processing chamber is separated from the plasma chamber by a separation grid;
flowing CF 4 at a flow rate of about 20 sccm to about 200 sccm, CH 4 at a flow rate of about 20 sccm to about 200 sccm, O 2 at a flows rate of about 500 sccm to about 1500 sccm, and N 2 at a flow rate of about 100 sccm to about 500 sccm into a plasma chamber to form a deposition process gas;
generating a deposition plasma in the plasma chamber from the deposition process gas;
filtering the deposition plasma via the separation grid to generate a filtered deposition mixture;
exposing the workpiece to the filtered deposition mixture, wherein the filtered deposition mixture deposits a passivation layer on a surface of each of the silicon dioxide layers, wherein the passivation layer comprises a fluorocarbon polymer, a hydrofluorocarbon polymer, a slat ammonium silicon fluoride salt, or a combination thereof;
generating an etching plasma in the plasma chamber;
filtering the etching plasma via the separation grid to generate a filtered etching mixture; and
exposing the workpiece to the filtered etching mixture, wherein the filtered etching mixture removes at least a portion of the plurality of silicon nitride layers laterally at an etch rate that is greater than an etch rate of the plurality of silicon dioxide layers.
17. The method of claim 16 , further comprising cyclically alternating exposing the workpiece to the filtered deposition mixture and exposing the workpiece to the filtered etching mixture.