Pressure purge etch method for etching complex 3-D structures

Patent metadata

Field	Value
Publication number	US-9870932-B1
Application number	US-201615220785-A
Country	US
Kind code	B1
Filing date	Jul 27, 2016
Priority date	Jul 27, 2016
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

A method for etching a substrate and removing byproducts includes a) setting process parameters of a processing chamber for a selective dry etch process; b) setting process pressure of the processing chamber to a first predetermined pressure in a range from 1 Torr to 10 Torr for the selective dry etch process; c) selectively etching a first film material of a substrate relative to a second film material of the substrate in the processing chamber during a first period; d) lowering pressure in the processing chamber to a second predetermined pressure that is less than the first predetermined pressure by a factor greater than or equal to 4; and e) purging the processing chamber at the second predetermined pressure for a second period.

First claim

What is claimed is:

1. A method for etching a substrate and removing byproducts, the substrate comprising a stack including a plurality of first layers and a plurality of second layers, the first layers alternating with the second layers, the method comprising:
a) setting process parameters of a processing chamber for a selective dry etch process;
b) setting process pressure of the processing chamber to a first predetermined pressure in a range from 1 Torr to 10 Torr for the selective dry etch process;
c) selectively etching a portion of one of the first layers relative to one of the second layers in the processing chamber during a first period;
d) lowering pressure in the processing chamber to a second predetermined pressure that is less than the first predetermined pressure by a factor greater than or equal to 4 in order to purge the processing chamber at the second predetermined pressure for a second period;
e) purging the processing chamber at the second predetermined pressure for the second period; and
repeating a) through e) or b) through e) N times, where N is an integer greater than one.

2. The method of claim 1 , further comprising varying at least one of the first predetermined pressure and the first period during at least one of the N times.

3. The method of claim 1 , further comprising varying at least one of the second predetermined pressure and the second period during at least one of the N times.

4. The method of claim 1 , wherein the selective dry etch process uses remote plasma.

5. The method of claim 4 , wherein the remote plasma is maintained during b) through de).

6. The method of claim 4 , wherein the remote plasma is ignited prior to c) and extinguished after c).

7. The method of claim 4 , wherein the remote plasma is generated using process gas including fluorine gas.

8. The method of claim 1 , wherein the processing chamber includes:
an upper chamber region;
an inductive coil arranged outside of the upper chamber region;
a lower chamber region including a substrate support; and
a gas dispersion device arranged between the upper chamber region and the lower chamber region.

9. The method of claim 8 , wherein:
the gas dispersion device includes a plurality of holes in fluid communication with the upper chamber region and the lower chamber region; and
inductively coupled plasma is generated in the upper chamber region by supplying power to the inductive coil.

10. A method for etching a substrate and removing byproducts, the substrate comprising a stack including a plurality of first layers and a plurality of second layers, the first layers alternating with the second layers, comprising:
a) setting process parameters of a processing chamber for an etch process;
b) setting process pressure of the processing chamber to a first predetermined pressure in a range from 1 Torr to 3 Torr for the etch process;
c) selectively etching a portion of one of the first layers relative to one of the second layers in the processing chamber during a first period;
d) lowering pressure in the processing chamber to a second predetermined pressure that is less than the first predetermined pressure by a factor greater than or equal to 4 in order to purge the processing chamber at the second predetermined pressure for a second period;
e) purging the processing chamber at the second predetermined pressure for the second period; and
f) repeating b) through e) N times, where N is an integer greater than one.

11. The method of claim 10 , further comprising varying at least one of the first predetermined pressure and the first period during at least one of the N times.

12. The method of claim 10 , further comprising varying at least one of the second predetermined pressure and the second period during at least one of the N times.

13. The method of claim 10 , wherein the etch process uses remote plasma.

14. The method of claim 13 , wherein the remote plasma is maintained during b) through de).

15. The method of claim 13 , wherein the remote plasma is ignited prior to c) and extinguished after c).

16. The method of claim 13 , wherein the remote plasma is generated using process gas including fluorine gas.

17. The method of claim 10 , wherein the processing chamber includes:
an upper chamber region;
an inductive coil arranged outside of the upper chamber region;
a lower chamber region including a substrate support; and
a gas dispersion device arranged between the upper chamber region and the lower chamber region.

18. The method of claim 17 , wherein:
the gas dispersion device includes a plurality of holes in fluid communication with the upper chamber region and the lower chamber region; and
inductively coupled plasma is generated in the upper chamber region by supplying power to the inductive coil.

19. A method for etching a substrate and removing byproducts, the substrate comprising a stack including a plurality of first layers and a plurality of second layers, the first layers alternating with the second layers, the method comprising:
a) setting process parameters of a processing chamber for a selective dry etch process;
b) setting process pressure of the processing chamber to a first predetermined pressure for the selective dry etch process;
c) selectively etching a portion of one of the first layers relative to one of the second layers in the processing chamber during a first period;
d) lowering pressure in the processing chamber to a second predetermined pressure that is less than the first predetermined pressure in order to purge the processing chamber at the second predetermined pressure for a second period;
e) purging the processing chamber at the second predetermined pressure for the second period; and
f) repeating a) through e) or b) through e) N times, where N is an integer greater than one.

Assignees

• Lam Res Corp

Inventors

• Park Pilyeon
• Guha Joydeep

Classifications

• H10P72/0421 Primary

  for drying etching · CPC title

• H01J37/3211 Primary

  Antennas, e.g. particular shapes of coils · CPC title

• H01L27/11578

  Electricity · mapped topic

• H01J37/32357

  Generation remote from the workpiece, e.g. down-stream · CPC title

• H01L27/11551

  Electricity · mapped topic