ETCH METHOD IN THE MANUFACTURE OF AN INTEGRATED CIRCUIT
The present invention provides a method for etching a substrate in the manufacture of a semiconductor device, the method comprising contacting a surface of the substrate with ions extracted from a plasma formed from a gas comprising one or more of an oxygen-containing species, a nitrogen-containing species and an inert gas, and separately contacting the surface of the substrate with a plasma formed from a gas comprising a fluorine-containing species.
1 . A method for etching a substrate in the manufacture of a semiconductor device, the method comprising:
contacting a surface of the substrate with ions extracted from a plasma formed from a gas comprising one or more of an oxygen-containing species, a nitrogen-containing species and an inert gas, and separately contacting the surface of the substrate with a plasma formed from a gas comprising a fluorine-containing species.
2 . The method as claimed in claim 1 , wherein the fluorine-containing species is a fluorocarbon.
3 . The method according to claim 2 , wherein the fluorine-containing species comprises one or more of CF 4 , CHF 3 , CH 2 F 2 , C 2 F 6 , C 4 F 6 , octafluorocyclobutane and C 5 F 8 .
4 . The method according to claim 1 , wherein the gas comprising the fluorine-containing species is essentially oxygen-free.
5 . The method as claimed in claim 1 , wherein the inert gas is a noble gas.
6 . The method as claimed in claim 4 , wherein the inert gas comprises one or more of helium, neon and argon.
7 . The method as claimed in claim 1 , wherein the oxygen-containing species comprises one or more of O 2 , CO, CO 2 , N 2 O and H 2 O.
8 . The method as claimed in claim 1 , wherein the nitrogen-containing species comprises N 2 .
9 . The method as claimed in claim 1 , the method comprising:
(A) forming a first plasma from a first gas comprising an oxygen-containing species;
(B) extracting ions from the first plasma;
(C) contacting a surface of the substrate with the ions extracted from the first plasma;
(D) forming a second plasma from a second gas comprising a fluorine-containing species; and
(E) contacting the surface of the substrate with at least a portion of the second plasma.
10 . The method according to claim 9 , wherein the portion of the plasma contacting the surface of the substrate in step (C) and/or step (E) contains essentially only ions.
11 . The method according to claim 10 , wherein the ions contacting the surface of the substrate in step (C) and/or step (E) are positive ions.
12 . The method according to claim 10 , wherein the ions contacting the surface in step (C) and/or step (E) have an energy less than the physical sputtering threshold energy of the surface.
13 . The method according to claim 9 , wherein steps A to E are repeated until a pre-determined semiconductor depth has been etched.
14 . The method according to claim 9 , wherein the surface of the substrate comprises an oxidizable material.
15 . The method according to claim 9 , wherein the surface of the substrate comprises one or more of Si, Ge, Ru, Mo and W.
16 . The method according to claim 9 , wherein the temperature of the substrate in step (C) and/or step (E) is less than 300° C.
17 . A method according to claim 1 , the method comprising:
(A) forming a first plasma from a first gas comprising a fluorocarbon;
(B) contacting the surface of the substrate with at least a portion of the first plasma;
(C) forming a second plasma from a second gas comprising one or more of an oxygen-containing species, a nitrogen-containing species and an inert gas;
(D) extracting ions from the second plasma; and
(E) contacting the surface of the substrate with the ions extracted from the second plasma.
18 . The method according to claim 17 , wherein the portion of the plasma contacting the surface of the substrate in step (B) and/or step (E) contains essentially only ions.
19 . The method according to claim 18 , wherein the ions contacting the surface in step (B) and/or step (E) of the substrate are positive ions.
20 . The method according to either claim 18 , wherein essentially all of the ions contacting the surface in step (B) and/or step (E) have an energy less than the physical sputtering threshold energy of the surface.
21 . The method according to claim 17 , wherein steps A to E are repeated until a pre-determined semiconductor depth has been etched.
22 . The method according to claim 17 , wherein the surface of the substrate comprises one or more of Si, Ge, Ru, Mo and W.
23 . The method according to claim 17 , wherein the temperature of the substrate in step (B) and/or step (E) is less than 300° C.