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 . A method for etching comprising:
a) supporting a substrate on a chuck in a chamber of a plasma treatment system, the substrate including a silicon containing stack, 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 phosphorus containing gas; and
e) generating a plasma from the halogen containing gas and the phosphorus containing gas wherein the plasma modifies the silicon containing stack providing a modified layer;
f) activating the modified layer of the stack; and
g) etching features in the silicon containing stack.
2 . The method, as recited in claim 1 , further comprising providing a bias.
3 . The method, as recited in claim 1 , wherein the generating the plasma from the halogen containing gas and phosphorus containing gas into a plasma comprises providing RF power.
4 . The method, as recited in claim 1 , wherein the phosphorus containing gas comprises phosphorus pentafluoride (PF 5 ).
5 . The method, as recited in claim 1 , wherein the halogen containing gas comprises a free fluorine providing component.
6 . The 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.
7 . The method, as recited in claim 1 , further comprising providing oxygen gas.
8 . The method, as recited in claim 1 , further comprising providing a bias with a magnitude of at least 400 volts.
9 . The method, as recited in claim 1 , wherein the substrate comprises at least two different silicon containing layers.
10 . The 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 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 . A method for etching comprising:
a) supporting a substrate on a chuck in a chamber of a plasma treatment system, the substrate including a silicon containing stack, and the chuck having a lower electrode;
b) providing a halogen containing gas;
c) providing a phosphorus containing gas; and
f) providing RF power to generate a plasma from the halogen containing gas and the phosphorus containing 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 method, as recited in claim 12 , further comprising providing a bias.
14 . The method, as recited in claim 12 , wherein the phosphorus containing gas comprises phosphorus pentafluoride (PF 5 ).
15 . The method, as recited in claim 12 , further comprising cooling the substrate to a temperature below −20° C.
16 . The method, as recited in claim 12 , wherein the halogen containing gas comprises a free fluorine providing component.
17 . The 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.
18 . The method, as recited in claim 12 , further comprising providing oxygen gas.
19 . The method, as recited in claim 12 , further comprising providing a bias with a magnitude of at least 400 volts.
20 . The method, as recited in claim 12 , wherein the substrate comprises at least two different silicon containing layers.