Opening hard mask and SOI substrate in single process chamber
View Patent ↗Methods for opening a hard mask and a silicon-on-insulator substrate in a single process chamber are disclosed. In one embodiment, the method includes patterning a photoresist over a stack including an anti-reflective coating (ARC) layer, a silicon dioxide (SiO 2 ) based hard mask layer, a silicon nitride pad layer, a silicon dioxide (SiO 2 ) pad layer and the SOI substrate, wherein the SOI substrate includes a silicon-on-insulator layer and a buried silicon dioxide (SiO 2 ) layer; and in a single process chamber: opening the ARC layer; etching the silicon dioxide (SiO 2 ) based hard mask layer; etching the silicon nitride pad layer; etching the silicon dioxide (SiO 2 ) pad layer; and etching the SOI substrate. Etching all layers in a single chamber reduces the turn-around-time, lowers the process cost, facilitates process control and/or improve a trench profile.
1. A method of opening a hard mask and a silicon-on-insulator (SOI) substrate, the method comprising the steps of:
patterning a photoresist over a stack including an anti-reflective coating (ARC) layer, a silicon dioxide (SiO 2 ) based hard mask layer, a silicon nitride pad layer, a silicon dioxide (SiO 2 ) pad layer and the SOI substrate, wherein the SOI substrate includes a silicon-on-insulator (SOI) layer and a buried silicon dioxide (SiO 2 ) layer; and
in a single process chamber:
opening the ARC layer;
etching the silicon dioxide (SiO 2 ) based hard mask layer;
etching the silicon nitride pad layer;
etching the silicon dioxide (SiO 2 ) pad layer; and
etching the SOI substrate, wherein the etch chemistry for etching the SOI substrate includes:
using approximately 80-100 standard cubic centimeters per minute (sccm) of difluoromethane (CH 2 F 2 ), approximately 35-45 sccm of tetrafluoromethane (CF 4 ) approximately 25-30 sccm of oxygen (O 2 ) and approximately 180-220 sccm of nitrogen (N 2 ) for the SOI layer; and
using approximately 10-30 sccm oxygen (O 2 ) 10-40 sccm hexafluorobutadiene (C 4 F 6 ) and 900-1200 sccm argon (Ar) for the buried silicon dioxide (SiO 2 ) layer.
2. The method of claim 1 , wherein the etch chemistry for the SOI layer includes: approximately 90 sccm of difluoromethane (CH 2 F 2 ), approximately 40 sccm of tetrafluoromethane (CF 4 ), approximately 27 sccm of oxygen (O 2 ) and approximately 200 sccm of nitrogen (N 2 ).
3. The method of claim 1 , wherein the SOI substrate etching step further includes overetching into a bulk silicon substrate under the SOI substrate.
4. The method of claim 3 , wherein the overetching step includes using approximately 80-100 standard cubic centimeters per minute (sccm) of difluoromethane (CH 2 F 2 ), approximately 35-45 sccm of tetrafluoromethane (CF 4 ), approximately 25-30 sccm of oxygen (O 2 ) and approximately 180-220 sccm of nitrogen (N 2 ).
5. The method of claim 1 , wherein the ARC layer opening step includes etching using approximately 100-200 standard cubic centimeters per minute (sccm) of tetrafluoromethane (CF 4 ) with a power of 400-700 Watts and a pressure of 50-150 milli-Torr.
6. The method of claim 1 , wherein the silicon dioxide (SiO 2 ) based hard mask layer etching step includes using 10-30 standard cubic centimeters per minute (sccm) oxygen (O 2 ), 10-40 sccm hexafluorobutadiene (C 4 F 6 ) and 900-1200 sccm argon (Ar).
7. The method of claim 1 , wherein the silicon nitride pad layer and the silicon dioxide (SiO 2 ) pad layer etching steps include using 50-100 standard cubic centimeters per minute (sccm) difluoromethane (CH 2 F 2 ), 10-40 sccm oxygen (O 2 ), 40-80 sccm tetrafluoromethane (CF 4 ) and 400-1000 sccm argon (Ar).
8. A method of opening a hard mask and a silicon-on-insulator (SOI) substrate, the method comprising the steps of:
patterning a photoresist over a stack including an anti-reflective coating (ARC) layer, a silicon dioxide (SiO 2 ) based hard mask layer, a silicon nitride pad layer, a silicon dioxide (SiO 2 ) pad layer and the SOI substrate, wherein the SOI substrate includes a silicon-on-insulator (SOI) layer and a buried silicon dioxide (SiO 2 ) layer; and
in a single process chamber:
opening the ARC layer;
etching the silicon dioxide (SiO 2 ) based hard mask layer;
etching the silicon nitride pad layer;
etching the silicon dioxide (SiO 2 ) pad layer; and
etching the SOI substrate using an etch chemistry including:
approximately 90 standard cubic centimeters per minute (sccm) of difluoromethane (CH 2 F 2 ), approximately 40 sccm of tetrafluoromethane (CF 4 ), approximately 27 sccm of oxygen (O 2 ) and approximately 200 sccm of nitrogen (N 2 ) for the SOI layer.
9. The method of claim 8 , wherein the SOI substrate etching step further includes using approximately 10-30 sccm oxygen (O 2 ), 10-40 sccm hexafluorobutadiene (C 4 F 6 ) and 900-1200 sccm argon (Ar) for the buried silicon dioxide (SiO 2 ) layer.
10. The method of claim 8 , wherein the SOI substrate etching step further includes overetching into a bulk silicon substrate under the SOI substrate.
11. The method of claim 10 , wherein the overetching step includes using approximately 80-100 sccm of difluoromethane (CH 2 F 2 ), approximately 35-45 sccm of tetrafluoromethane (CF 4 ), approximately 25-30 sccm of oxygen (O 2 )and approximately 180-220 sccm of nitrogen (N 2 ).
12. The method of claim 8 , wherein the ARC layer opening step includes etching using approximately 100-200 sccm of tetrafluoromethane (CF 4 ) with a power of 400-700 Watts and a pressure of 50-150 milli-Torr.
13. The method of claim 8 , wherein the silicon dioxide (SiO 2 ) based hard mask layer etching step includes using 10-30 sccm oxygen (O 2 ), 10-40 sccm hexafluorobutadiene (C 4 F 6 ) and 900-1200 sccm argon (Ar).
14. The method of claim 8 , wherein the silicon nitride pad layer and the silicon dioxide (SiO 2 ) pad layer etching steps include using 50-100 sccm difluoromethane (CH 2 F 2 ), 10-40 sccm oxygen (O 2 ), 40-80 sccm tetrafluoromethane (CF 4 ) and 400-1000 sccm argon (Ar).
15. A method of opening a hard mask and a silicon-on-insulator (SOI) substrate, the method comprising the steps of:
providing a stack including an anti-reflective coating (ARC) layer, a silicon dioxide (SiO 2 ) based hard mask layer, a silicon nitride pad layer, a silicon dioxide (SiO 2 ) pad layer and the SOI substrate, wherein the SOI substrate includes a silicon-on-insulator (SOI) layer and a buried silicon dioxide (SiO 2 ) layer;
patterning a photoresist over the stack; and
in a single process chamber:
opening the ARC layer;
etching the silicon dioxide (SiO 2 ) based hard mask layer;
etching the silicon nitride pad layer;
etching the silicon dioxide (SiO 2 ) pad layer; and
etching the SOI substrate using an etch chemistry including:
approximately 90 standard cubic centimeters per minute (sccm) of difluoromethane (CH 2 F 2 ), approximately 40 sccm of tetrafluoromethane (CF 4 ), approximately 27 sccm of oxygen (O 2 ) and approximately 200 sccm of nitrogen (N 2 ) for the SOI layer, and
approximately 10-30 sccm oxygen (O 2 ), 10-40 sccm hexafluorobutadiene (C 4 F 6 ) and 900-1200 sccm argon (Ar) for the buried silicon dioxide (SiO 2 ) layer.
16. The method of claim 15 , wherein the SOI substrate etching step further includes overetching into a bulk silicon substrate under the SOI substrate.
17. The method of claim 16 , wherein the overetching step includes using approximately 80-100 sccm of difluoromethane (CH 2 F 2 ), approximately 35-45 sccm of tetrafluoromethane (CF 4 ), approximately 25-30 sccm of oxygen (O 2 ) and approximately 180-220 sccm of nitrogen (N 2 ).
18. The method of claim 15 , wherein the ARC layer opening step includes etching using approximately 100-200 sccm of tetrafluoromethane (CF 4 ) with a power of 400-700 Watts and a pressure of 50-150 milli-Torr.
19. The method of claim 15 , wherein the silicon dioxide (SiO 2 ) based hard mask layer etching step includes using 10-30 sccm oxygen (O 2 ), 10-40 sccm hexafluorobutadiene (C 4 F 6 ) and 900-1200 sccm argon (Ar), and the silicon nitride pad layer and the silicon dioxide (SiO 2 ) pad layer etching steps include using 50-100 sccm difluoromethane (CH 2 F 2 ), 10-40 sccm oxygen (O 2 ), 40-80 sccm tetrafluoromethane (CF 4 ) and 400-1000 sccm argon (Ar).