Method for fabricating semiconductor device and forming interlayer dielectric film using high-density plasma
View Patent ↗A method for fabricating a semiconductor device and forming an insulating film used therein, includes forming an isolation insulating film on a semiconductor wafer and forming gates, separated by gaps having a predetermined distance, on an active region. Next, a first interlayer dielectric film is deposited to a predetermined thickness on the semiconductor wafer having the gates, so that the gaps between the gates are not completely filled. Then, a sputtering etch is performed entirely on a surface of the first interlayer dielectric film. Thereafter, the first interlayer dielectric film is partially removed through isotropic etching. Next, a second interlayer dielectric film is deposited on the first interlayer dielectric film so that the gaps between the gates are completely filled. According to the above method, a gap between gate patterns can be completely filled without a void by performing sputtering etch on interlayer dielectric films formed on gate patterns, thereby enhancing the reliability of a semiconductor device.
1. A method for forming an interlayer dielectric film by high-density plasma, using an apparatus for fabricating a semiconductor device which includes a reactor having a wafer supporter on which a semiconductor wafer is placed and a gas supplier for supplying reactant gas to the semiconductor wafer, and is used for generating high-density plasma for chemical vapor deposition, the method comprising the steps of:
(a) placing the semiconductor wafer having a predetermined pattern in the reactor;
(b) supplying reactant gas to the semiconductor wafer in the reactor while the reactor is maintained to have low pressure;
(c) changing the reactant gas into a plasma state and bringing the plasmic reactant gas into contact with a surface of the semiconductor wafer, so that a first interlayer dielectric film is formed;
(d) providing an atmospheric gas into the reactor;
(e) performing a sputtering etch on the first interlayer dielectric film by changing the atmospheric gas into plasma and colliding the plasma against the wafer surface;
(f) performing a wet etch on the first interlayer dielectric film after the sputtering etch; and
(g) forming a second interlayer dielectric film on the first interlayer dielectric film.
2. The method of claim 1 , wherein the reaction gas comprises silane gas (SiH 4 ) and oxygen gas (O 2 ).
3. The method of claim 2 , wherein more oxygen gas (O 2 ) is supplied than silane gas (SiH 4 ).
4. The method of claim 2 , wherein the silane gas (SiH 4 ) is supplied at a flow rate of 30˜300 sccm.
5. The method of claim 2 , wherein the reactant gas further comprises oxygen gas (O 2 ) and helium gas (He) as reactant auxiliary gas.
6. The method of claim 2 , wherein the oxygen gas (O 2 ) is supplied at a flow rate of 50˜500 sccm.
7. The method of claim 5 , wherein the helium gas (He) is supplied at a flow rate of 50˜1000 sccm.
8. The method of claim 1 , wherein the step (c) further comprises applying high-frequency power to the reactor.
9. The method of claim 8 , wherein low-frequency power is further applied to the reactor.
10. The method of claim 9 , wherein the high-frequency power is less than the low-frequency power.
11. The method of claim 8 , wherein the high-frequency power is radio frequency power.
12. The method of claim 10 , wherein the high-frequency power is applied to the wafer supporter and the low frequency power is applied to an upper wall of the reactor.
13. The method of claim 12 , wherein the low-frequency power is in a range of 2500˜3500 W.
14. The method of claim 12 , wherein the high-frequency power is in the range of 500˜1500 W.
15. The method of claim 1 , wherein the interlayer dielectric film comprises a silicon oxide (SiO 2 ) film.
16. The method of claim 1 , wherein the atmospheric gas for the sputtering etch in the step (e) comprises at least one of oxygen gas (O 2 ) and helium gas (He).
17. The method of claim 16 , wherein the oxygen gas (O 2 ) is supplied at a flow rate of 0˜500 sccm.
18. The method of claim 16 , wherein the helium gas (He) is supplied at a flow rate of 0˜1000 sccm.
19. The method of claim 1 , wherein the step (e) further comprises a step of applying high-frequency power and low-frequency power to the reactor at a same time.
20. The method of claim 19 , wherein the high-frequency power comprises radio frequency power.
21. The method of claim 19 , wherein the low-frequency power is in a range of 100˜1000 kHz.
22. The method of claim 19 , wherein the high-frequency power is applied to the wafer supporter and the low-frequency power is applied to the upper wall of the reactor.
23. The method of claim 22 , wherein the low-frequency power is greater than the high-frequency power.
24. The method of claim 22 , wherein the low-frequency power applied is in a range of 3500˜5000 W.
25. The method of claim 22 , wherein the high-frequency power applied is in a range of 500˜3000 W.