Gap fill for high aspect ratio structures

• US 6,596,654 B1
• Filed: 11/28/2001
• Issued: 07/22/2003
• Est. Priority Date: 08/24/2001
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Singh, Vikram, Gauri, Vishal, van Schravendijk, Bart, Zhang, Weijie, Bayman, Atiye, Rahman, Md Sazzadur, Papasoulitotis, George D.
• Primary Examiner(s): Whitehead, Jr., Carl
• Assistant Examiner(s): Hogans, David L.
• Application Number:
  US09/996,619
• Time in Patent Office: 601 Days
• Field of Search: 438/778, 438/787-794, 156/345, 204/192.3
• US Class Current: 438/788
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: H01J 2237/3327 Coating high aspect ratio workpieces
• CPC Class Codes: H01L 21/02129 the material being boron or phosphorus doped silicon oxides, e.g. BPSG, BSG or PSG
• CPC Class Codes: H01L 21/02131 the material being halogen doped silicon oxides, e.g. FSG
• CPC Class Codes: H01L 21/0214 the material being a silicon oxynitride, e.g. SiON or SiON:H
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/3144 on silicon
• CPC Class Codes: H01L 21/3145 formed by deposition from a gas or vapour
• CPC Class Codes: H01L 21/31608 Deposition of SiO2 H01L21/31625, H01L21/31629 and H01L21/31633 take precedence
• CPC Class Codes: H01L 21/31625 Deposition of boron or phosphorus doped silicon oxide, e.g. BSG, PSG, BPSG
• CPC Class Codes: H01L 21/31629 Deposition of halogen doped silicon oxide, e.g. fluorine doped silicon oxide
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264

Abstract

Chemical vapor deposition processes are employed to fill high aspect ratio (typically at least 3:1), narrow width (typically 1.5 microns or less and even sub 0.15 micron) gaps with significantly reduced incidence of voids or weak spots. This deposition process involves the use of hydrogen as a process gas in the reactive mixture of a plasma containing CVD reactor. The process gas also includes dielectric forming precursor molecules such as silicon and oxygen containing molecules.

Claims

1. A method of filling gaps on a semiconductor substrate, the method comprising

providing a substrate in a process chamber of a high density plasma chemical vapor deposition reactor;

introducing a process gas comprising at least about 400 sccm hydrogen into the process chamber; and

applying a bias to the substrate, to thereby grow a dielectric film via high density plasma chemical vapor deposition on the semiconductor substrate, wherein the dielectric film fills gaps with a width of less than about 1.5 micrometer.

2. The method of claim 1, wherein the process gas further comprises a silicon-bearing compound selected from the group of SiH₄, SiF₄, Si₂H₆, TEOS, TMCTS, OMCTS, methyl-silane, dimethyl-silane, 3MS, 4MS, TMDSO, TMDDSO, DMDMS and mixtures thereof, said process further comprising decomposing the silicon-containing compound to allow plasma phase reacting of a silicon-containing reactant on the surface of the substrate.

3. The method of claim 2, wherein the process gas further comprises a reactant selected from the group consisting of N₂, N₂O, NO, NH₃, NF₃, O₂, and mixtures thereof.

4. The method of claim 3, wherein the process gas comprises a reactant selected from the group of boron-containing gas, phosphorus-containing gas, and mixtures thereof.

5. The method of claim 1, wherein the process chamber is maintained at a pressure of not more than about 100 mTorr.

6. The method of claim 1, wherein the high-density plasma chemical vapor deposition reactor comprises an electrode that generates a plasma from the process gas.

7. The method of claim 1, wherein the bias applied to the substrate is a radio frequency bias.

8. The method of claim 7, wherein applying a bias to the substrate comprises supporting the substrate on a substrate holder having an electrode supplying a radio frequency bias to the substrate, the radio frequency bias being generated by supplying the electrode with at least 0.2 W/cm² of power.

9. The method of claim 7, wherein the radio frequency bias applied to the substrate is at the frequency range of between about 100 kHz and 27 MHz.

10. The method of claim 1, wherein the substrate is placed on a substrate holder that is maintained at a temperature of between about 30 and 1000°

C.

11. The method of claim 1, further comprising supplying a heat transfer gas between a surface of the substrate and a surface of the substrate holder on which the substrate is supported during the film growing.

12. The method of claim 11, further comprising clamping the substrate on an electrostatic or mechanical chuck during the film growing.

13. The method of claim 12, wherein the heat transfer gas comprises at least one of helium and argon and is supplied to a space between the surface of the substrate and a surface of the chuck.

14. The method of claim 1, further comprising plasma phase reacting at least one of an oxygen-containing gas and a hydrogen-containing gas in the gaps and removing polymer residues in the gap prior to the film growing.

15. The method of claim 1, wherein the dielectric film comprises a silicon oxide.

16. The method of claim 1, wherein the dielectric film comprises SiO₂.

17. The method of claim 1, wherein the gas includes silicon and fluorine-containing reactants and the dielectric film comprises silicon oxyfluoride.

18. The method of claim 1, wherein the gas includes nitrogen-containing reactants and the dielectric film comprises silicon oxynitride.

19. The method of claim 1, wherein the gas includes phosphorus-containing reactants and the dielectric film comprises phosphorus-doped silicon oxide.

20. The method of claim 1, wherein the gas includes boron-containing reactants and the dielectric film comprises boron-doped silicon oxide.

21. The method of claim 1, wherein the gas includes boron-containing reactants and phosphorus-containing reactants and the dielectric film comprises phosphorus- and boron-doped silicon oxide (BPSG).

22. The method of claim 1, wherein the process gas is introduced through a gas supply including orifices, at least some of the orifices orienting the process gas along an axis of injection intersecting an exposed surfaced of the substrate at an acute angle.

23. The method of claim 22, wherein introducing the process gas comprises supplying a gas or gas mixture from a primary gas ring, wherein at least some of said gas or gas mixture is directed toward said substrate.

24. The method of claim 23, wherein injectors are connected to said primary gas ring, the injectors injecting at least some of said gas or gas mixture into said chamber and directed toward substrate.

25. The method of claim 1, wherein the gap filling method is employed to form shallow trench isolation (STI) regions.

26. The method of claim 1, wherein the width of the gaps are 0.15 micrometers or less.