Manufacturing method for semiconductor device
View Patent ↗A semiconductor device manufacturing method for suppressing surface roughness of a Low-k insulating film during etching. In a laminated structure comprising a layer having formed thereon a lower copper wiring, a SiC film and a SiOC film, a via and an upper copper wiring are formed as follows. The SiOC film is etched to form a via hole opening that reaches the SiC film and then to form wiring grooves that communicate with the opening. Thereafter, when the SiC film on the bottom of the opening is etched to form a via hole, a deposited film of etching products is formed on surfaces of the via hole and the wiring grooves. This deposited film allows planarization of the SiOC film surface, which is exposed to plasma, formed thereon the via hole and the wiring grooves. Subsequently, formation of a Ta film and burying of plating copper are performed.
1. A method for manufacturing a semiconductor device having a multilayer wiring structure, comprising the steps of:
forming an etch stop layer on a layer having formed thereon a lower copper wiring;
forming an interlayer insulating film on the etch stop layer;
etching the interlayer insulating film to form an opening that reaches the etch stop layer;
etching the interlayer insulating film to form a wiring groove that communicates with the opening;
etching the etch stop layer on the bottom of the opening to form a via hole as well as forming a deposited film of etching products on surfaces of the via hole and the wiring groove; and
forming a barrier metal in the via hole and the wiring groove by a sputtering method;
wherein in the step of forming the barrier metal by the sputtering method, the deposited film of the etching products on the bottom of the via hole is preferentially sputtered and removed, and the barrier metal is formed in a state where the deposited film of the etching products on the bottom of the via hole is removed,
wherein in the step of etching the etch stop layer on the bottom of the opening to form the via hole that communicates with the lower copper wiring as well as forming the deposited film of the etching products on the surfaces of the via hole and the wiring groove,
the etch stop layer on the bottom of the opening is etched to form the via hole as well as the deposited film of the etching products is formed on the surfaces of the via hole and the wiring groove such that the surface roughness on the bottom of the wiring groove is 1 nm or less.
2. The method according to claim 1 , further comprising the step of:
burying copper in the via hole and the wiring groove, after the step of forming the barrier metal in the via hole and the wiring groove.
3. The method according to claim 1 , wherein:
in the step of etching the etch stop layer on the bottom of the opening to form the via hole as well as forming the deposited film of the etching products on the surfaces of the via hole and the wiring groove,
the deposited film of the etching products is formed to a film thickness of 1 to 20 nm.
4. The method according to claim 1 , wherein:
in the step of etching the etch stop layer on the bottom of the opening to form the via hole that communicates with the lower copper wiring as well as forming the deposited film of the etching products on the surfaces of the via hole and the wiring groove,
when using a hydrofluorocarbon gas as an etching gas, the etching is performed using a mixed gas comprising the hydrofluorocarbon gas with a flow rate of 1 to 200 sccm, an O 2 gas with a flow rate of 1 to 200 sccm, an N 2 gas with a flow rate of 1 to 200 sccm and an Ar gas with a flow rate of 0 to 1000 sccm under conditions that a pressure is 1 to 300 mTorr, a supply power is 100 to 1000 W and a magnetic field is 0 to 100 G.
5. The method according to claim 4 , wherein:
the hydrofluorocarbon gas flow rate is set larger than the O 2 gas flow rate.
6. The method according to claim 4 , wherein:
the hydrofluorocarbon gas is a CH 2 F 2 gas or a CHF 3 gas.
7. The method according to claim 1 , wherein:
in the step of etching the etch stop layer on the bottom of the opening to form the via hole that communicates with the lower copper wiring as well as forming the deposited film of the etching products on the surfaces of the via hole and the wiring groove,
when using a fluorocarbon gas as an etching gas, the etching is performed using a mixed gas comprising the fluorocarbon gas with a flow rate of 1 to 200 sccm, an O 2 gas with a flow rate of 1 to 200 sccm, a N 2 gas with a flow rate of 1 to 200 sccm and an Ar gas with a flow rate of 0 to 1000 sccm under conditions that a pressure is 1 to 300 mTorr, a supply power is 100 to 1000 W and a magnetic field is 0 to 100 G.
8. The method according to claim 7 , wherein:
the fluorocarbon gas flow rate is set larger than the O 2 gas flow rate.
9. The method according to claim 7 , wherein:
the fluorocarbon gas is a C 4 F 6 gas.
10. The method according to claim 1 , wherein a surface roughness of the wiring groove is 1 nm or less.
11. A method for manufacturing a semiconductor device having a multilayer wiring structure, comprising the steps of:
forming an etch stop layer on a layer having formed thereon a lower copper wiring;
forming an interlayer insulating film on the etch stop layer;
etching the interlayer insulating film to form an opening that reaches the etch stop layer;
etching the interlayer insulating film to form a wiring groove that communicates with the opening;
etching the etch stop layer on the bottom of the opening to form a via hole that communicates with the lower copper wiring;
forming an insulating thin film on surfaces of the via hole and the wiring groove; and
forming a barrier metal in the via hole and the wiring groove by a sputtering method;
wherein in the step of forming the barrier metal by the sputter method, the insulating thin film on the bottom of the via hole is preferentially sputtered and removed, and the barrier metal is formed in a state where insulating thin film on the bottom of the via hole is removed,
wherein in the step of forming the insulating thin film on the surfaces of the via hole and the wiring groove, the insulating thin film is formed on the surfaces of the via hole and the wiring groove such that the surface roughness on the bottom of the wiring groove is 1 nm or less.
12. The method according to claim 11 , further comprising the step of:
burying copper in the via hole and the wiring groove, after the step of forming the barrier metal in the via hole and the wiring groove.
13. The method according to claim 11 , wherein:
in the step of forming the insulating thin film on the surfaces of the via hole and the wiring groove, the insulating thin film is formed using plasma.
14. The method according to claim 11 , wherein:
in the step of forming the insulating thin film on the surfaces of the via hole and the wiring groove, the insulating thin film is constructed by a SiO film, a SiOC film, a SiC film, a SiN film, an amorphous carbon film or a hydrocarbon film.
15. The method according to claim 11 , wherein:
in the step of forming the insulating thin film on the surfaces of the via hole and the wiring groove, the insulating thin film is formed to a film thickness of 1 to 30 nm.