Method of producing semiconductor device
View Patent ↗A method of producing a semiconductor device includes the steps of: preparing a base member; laminating sequentially a barrier film formed of titanium nitride, a wiring portion film formed of tungsten, and a mask film formed of titanium nitride on the base member to form a multi-layer film; forming a resist mask on the mask film so that the resist mask covers a wiring portion forming area and exposes a wiring portion non-forming area; etching the mask film using a first gas in which titanium nitride has a large etching ratio with respect to tungsten; and etching the wiring portion film using a second gas in which tungsten has a large etching ratio with respect to titanium nitride so that a portion of the wiring portion film in the wiring portion non-forming area is removed and a portion of the wiring portion film in the wiring portion forming area remains.
1. A method of producing a semiconductor device, comprising the steps of:
preparing a base member;
laminating sequentially a barrier film formed of titanium nitride, a wiring portion film formed of tungsten, and a mask film formed of titanium nitride on the base member;
forming a resist mask so that the resist mask covers a wiring portion forming area and exposes a wiring portion non-forming area;
etching the mask film using a first gas in which titanium nitride has an etching rate larger than that of tungsten so that a first portion of the mask film in the wiring portion forming area is removed and a second portion of the mask film in the wiring portion non-forming area remains; and
etching the wiring portion film using a second gas in which tungsten has an etching rate larger than that of titanium nitride so that a third portion of the wiring portion film in the wiring portion non-forming area is removed and a fourth portion of the wiring portion film in the wiring portion forming area remains to form a wiring portion.
2. The method according to claim 1 , wherein, in the step of etching the mask film using the first gas, said first gas includes a chlorine type gas, and, in the step of the wiring portion film using the second gas, said second gas includes a fluorine type gas.
3. The method according to claim 1 , wherein, in the step of etching the mask film using the first gas, said first gas includes a chlorine type gas containing Cl 2 , and, in the step of the wiring portion film using the second gas, said second gas includes a fluorine type gas containing SF 6 .
4. The method according to claim 1 , further comprising the steps of removing a fifth portion of the resist mask remaining after the step of etching the wiring portion film, and removing the second portion and the barrier film in the wiring portion non-forming area on the wiring portion.
5. The method according to claim 4 , wherein, in the step of removing the second portion and the barrier film in the wiring portion non-forming area, the second portion and the barrier film in the wiring portion non-forming area are etched using the first gas.
6. The method according to claim 1 , further comprising the steps of forming an interlayer insulation film on the base member for embedding the wiring portion, forming a through hole in the interlayer insulation film for exposing the wiring portion, filling the through hole with a conductive member, and forming an upper layer wiring portion on the interlayer insulation film.
7. The method according to claim 1 , further comprising the steps of forming an anti-reflection film on the mask film, coating resist on the anti-reflection film to form a resist film, etching the resist film to form the resist mask, etching the anti-reflection film using a fluorine type gas so that a sixth portion of the anti-reflection film in the wiring portion forming area is removed and a seventh portion of the anti-reflection film in the wiring portion non-forming area remains.
8. The method according to claim 7 , wherein, in the step of etching the anti-reflection film using the fluorine type gas, said fluorine type gas contains CHF 3 .
9. The method according to claim 7 , wherein, in the step of etching the anti-reflection film using the fluorine type gas, said anti-reflection film is etched through reactive ion etching at a bias power of 30 to 50 W.
10. The method according to claim 7 , wherein, in the step of etching the anti-reflection film using the fluorine type gas, said fluorine type gas contains CHF 3 and CF 4 at a flowing amount of CHF 3 at least six times larger than that of CF 4 .
11. The method according to claim 7 , further comprising the steps of removing a fifth portion of the resist mask and an eighth portion of the anti-reflection film remaining after the step of etching the wiring portion film, and removing the second portion and the barrier film in the wiring portion non-forming area on the wiring portion.
12. The method according to claim 11 , wherein, in the step of removing the second portion and the barrier film in the wiring portion non-forming area, the second portion and the barrier film in the wiring portion non-forming area are etched using the first gas.
13. The method according to claim 7 , further comprising the steps of forming an interlayer insulation film on the base member for embedding the wiring portion, forming a through hole in the interlayer insulation film for exposing the wiring portion, filling the through hole with a conductive member, and forming an upper layer wiring portion on the interlayer insulation film.
14. The method according to claim 1 , wherein, in the step of etching the wiring portion film using the second gas, said wiring portion film is etched to form the wiring portion having a width at most 150 nm.
15. The method according to claim 1 , wherein, in the step of etching the wiring portion film using the second gas, said wiring portion film is etched to form the wiring portion having a thickness at most 300 to 400 nm.