Plasma etching chemistries of high aspect ratio features in dielectrics
A method for etching features in a stack below a patterned mask in an etch chamber is provided. The stack is cooled with a coolant with a coolant temperature below −20° C. An etch gas is flowed into the etch chamber. A plasma is generated from the etch gas. Features are selectively etched into the stack with respect to the patterned mask.
1 . An etching method, comprising:
a) supporting a substrate on a chuck in a chamber of a plasma treatment system, the substrate including a silicon-containing film, and the chuck having a lower electrode;
b) cooling the substrate to a temperature below −20° C.;
c) providing a halogen containing gas;
d) providing a N 2 gas; and
e) generating a plasma from the halogen containing gas and the N 2 gas wherein the plasma modifies the silicon containing film providing a modified layer;
f) activating the modified layer of the silicon containing film; and
g) etching features in the silicon containing film.
2 . The etching method, as recited in claim 1 , wherein the halogen containing gas comprises at least one of XeF 2 , TaF 5 , IF 7 , HF, ClF 5 , NF 5 , NbF 5 , BiF 5 , UF 5 , SiCl 2 , CrO 2 Cl 2 , TaCl 4 , HfCl 4 , TiCl 3 (l), TiCl 4 (l), CoCl 2 (l), TiCl 3 , and TiCl 2 .
3 . The etching method, as recited in claim 1 , wherein the generating the plasma from the halogen containing gas and N 2 gas into a plasma comprises providing RF power.
4 . The etching method, as recited in claim 1 , wherein the halogen containing gas comprises a free fluorine providing component.
5 . The etching method, as recited in claim 1 , further comprising providing one or more of a hydrogen containing component, a hydrocarbon containing component, a fluorocarbon containing component, and an iodine containing component.
6 . The etching method, as recited in claim 1 , further comprising providing an oxygen containing component.
7 . The etching method, as recited in claim 1 , further comprising providing oxygen gas.
8 . The etching method, as recited in claim 1 , further comprising providing a bias with a magnitude of at least 400 volts.
9 . The etching method, as recited in claim 1 , wherein the substrate comprises at least two different silicon containing layers.
10 . The etching method, as recited in claim 9 , wherein the at least two different silicon containing layers comprise a silicon oxide layer and a silicon nitride layer.
11 . The etching method, as recited in claim 9 , wherein the at least two different silicon containing layers comprise a silicon oxide layer and a polysilicon layer.
12 . An etching method, comprising:
a) supporting a substrate on a chuck in a chamber of a plasma treatment system, the substrate including a silicon-containing film, and the chuck having a lower electrode;
b) providing a halogen containing gas;
c) providing a N 2 gas; and
f) generating a plasma from the halogen containing gas and the N 2 gas wherein the plasma modifies the silicon containing stack providing a modified layer;
g) activating the modified layer of the stack; and
h) etching features in the silicon containing stack.
13 . The etching method, as recited in claim 12 , wherein the halogen containing gas comprises at least one of XeF 2 , TaF 5 , IF 7 , HF, ClF 5 , NF 5 , NbF 5 , BiF 5 , UF 5 , SiCl 2 , CrO 2 Cl 2 , TaCl 4 , HfCl 4 , TiCl 3 (l), CoCl 2 (l), TiCl 3 , and TiCl 2 .
14 . The etching method, as recited in claim 12 , wherein the generating the plasma from the halogen containing gas and N 2 into a plasma comprises providing RF power.
15 . The etching method, as recited in claim 12 , wherein the halogen containing gas comprises a free fluorine providing component.
16 . The etching method, as recited in claim 12 , further comprising providing one or more of a hydrogen containing component, a hydrocarbon containing component, a fluorocarbon containing component, and an iodine containing component.
17 . The etching method, as recited in claim 12 , further comprising providing an oxygen containing component.
18 . The etching method, as recited in claim 12 , further comprising providing oxygen gas.
19 . The etching method, as recited in claim 12 , further comprising providing a bias with a magnitude of at least 400 volts.
20 . The etching method, as recited in claim 12 , wherein the substrate comprises at least two different silicon containing layers.