Etching method and plasma processing apparatus
An etching method and a plasma processing apparatus form a recess with an intended shape. The etching method includes (a) providing a substrate, the substrate including a silicon-containing film and a mask on the silicon-containing film; (b) etching the silicon-containing film with a first plasma to form a recess, the first plasma generated from a first process gas; (c) supplying a second plasma to the substrate, the second plasma generated from a second process gas comprising tungsten; and (d) etching the recess with a third plasma generated from a third process gas.
1 . An etching method, comprising:
(a) providing a substrate, the substrate including a silicon-containing film and a mask on the silicon-containing film;
(b) etching, while a bias power greater than zero is provided to a support of the substrate, the silicon-containing film with a first plasma to form a recess, wherein the first plasma is generated from a first process gas;
(c) forming a tungsten-containing layer on a side wall of the recess by supplying, while zero bias power is provided to the support, a second plasma to the substrate, wherein the second plasma is generated from a second process gas comprising tungsten; and
(d) etching the recess with a third plasma generated from a third process gas.
2 . The etching method according to claim 1 , wherein
(b) includes generating the first plasma at a first pressure, and
(c) includes generating the second plasma at a second pressure higher than the first pressure.
3 . The etching method according to claim 1 , wherein
(b) includes providing a first radio-frequency power, separate from the bias power, to generate the first plasma, and
(c) includes providing a second radio-frequency power, separate from the bias power, at a lower power level than the first radio-frequency power to generate the second plasma.
4 . The etching method according to claim 1 , further comprising:
(e) removing a deposit in an opening in the mask resulting from (b) and before (c).
5 . The etching method according to claim 1 , further comprising:
(f) supplying a fourth plasma to the substrate after (b) and before (c), the fourth plasma generated from a fourth process gas comprising an oxygen-containing gas.
6 . The etching method according to claim 1 , wherein (c) and (d) are repeated after (d).
7 . The etching method according to claim 1 , wherein
the silicon-containing film includes a first layer comprising a first material comprising silicon and a second layer comprising a second material different from the first material, and
the first layer and the second layer are alternately stacked on one another.
8 . The etching method according to claim 7 , wherein the first material comprises silicon oxide.
9 . The etching method according to claim 7 , wherein the second material comprises silicon nitride.
10 . The etching method according to claim 1 , wherein the second process gas comprises a tungsten-containing gas.
11 . The etching method according to claim 1 , wherein the second process gas comprises a tungsten hexafluoride gas.
12 . The etching method according to claim 1 , wherein the first process gas comprises a C x H y F z gas, where x and z are integers greater than or equal to 1, and y is an integer greater than or equal to 0.
13 . The etching method according to claim 1 , wherein the third process gas comprises a C x H y F z gas, where x and z are integers greater than or equal to 1, and y is an integer greater than or equal to 0.
14 . An etching method, comprising:
(a) providing a substrate, the substrate including a silicon-containing film and a mask on the silicon-containing film, and the silicon-containing film including silicon oxide films and silicon nitride films alternately stacked on one another;
(b) etching, while a bias power greater than zero is provided to a support of the substrate, the silicon-containing film with a first plasma to form a recess, wherein the first plasma is generated from a first process gas comprising a C x H y F z gas and an oxygen-containing gas, where x and z are integers greater than or equal to 1, and y is an integer greater than or equal to 0;
(c) forming a tungsten-containing layer on a side wall of the recess by supplying, while zero bias power is provided to the support, a second plasma to the substrate, wherein the second plasma is generated from a second process gas comprising a tungsten hexafluoride gas; and
(d) etching the recess with a third plasma generated from a third process gas comprising a C x H y F z gas and an oxygen-containing gas, where x and z are integers greater than or equal to 1, and y is an integer greater than or equal to 0.