METHOD AND APPARATUS FOR GROWING THIN OXIDE FILMS ON SILICON WHILE MINIMIZING IMPACT ON EXISTING STRUCTURES

• US 20100151694A1
• Filed: 12/12/2008
• Published: 06/17/2010
• Est. Priority Date: 12/12/2008
• Status: Active Grant

• Current Assignee: Mattson Technology, Inc. (Beijing Economic & Technology Development Area), BeiJing E-Town Semiconductor Technology Co., Ltd.
• Original Assignee: Mattson Technology, Inc. (Beijing Economic & Technology Development Area)
• Inventors: Xing, Guangcai, Peuse, Bruce W., Roters, Georg, Hu, Yaozhi, Sinha, Ashok, Tay, Sing-Pin, Timans, Paul Janis, Lerch, Wilfried, Savas, Stephen E., Nenyei, Zsolt
• Granted Patent: US 8,236,706 B2
• Time in Patent Office: Days
• US Class Current: 438/770
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/0223 formation by oxidation, e.g. oxidation of the substrate
• CPC Class Codes: H01L 21/02238 silicon in uncombined form, i.e. pure silicon
• CPC Class Codes: H01L 21/02252 formation by plasma treatment, e.g. plasma oxidation of the substrate after treatment of an insulating film by plasma H01L21/3105 and subgroups
• CPC Class Codes: H01L 21/02323 introduction of oxygen
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/31654 of semiconductor materials, e.g. the body itself
• CPC Class Codes: H01L 21/67115 mainly by radiation
• CPC Class Codes: H01L 21/67248 Temperature monitoring
• CPC Class Codes: H01L 21/68771 characterised by supporting more than one semiconductor substrate

Abstract

Plasma assisted low temperature radical oxidation is described. The oxidation is selective to metals or metal oxides that may be present in addition to the silicon being oxidized. Selectivity is achieved by proper selection of process parameters, mainly the ratio of H2 to O2 gas. The process window may be enlarged by injecting H2O steam into the plasma, thereby enabling oxidation of silicon in the presence of TiN and W, at relatively low temperatures. Selective oxidation is improved by the use of an apparatus having remote plasma and flowing radicals onto the substrate, but blocking ions from reaching the substrate.

Claims

1. A method for selective oxidation of silicon on a substrate in the presence of other materials, comprising:

placing the substrate in a vacuum processing chamber;

generating a plasma remotely from the substrate, such that no part of the plasma touches the substrate;

injecting into the plasma H2 and O2 gases;

providing flow path for radicals from the plasma to reach the substrate; and

,

preventing ions from reaching the substrate.

2. The method of claim 1, wherein the concentration of H2 to total gas flow is limited to at least 60%.

3. The method of claim 2, wherein the concentration of H2 flow to total gas flow is limited to less than 85%.

4. The method of claim 1, wherein the concentration of H2 flow to total gas flow is limited to between 60% and 85%.

5. The method of claim 1, further comprising illuminating the substrate with a UV source.

6. The method of claim 5, further comprising injecting steam into the plasma.

7. The method of claim 1, further comprising injecting steam into the plasma.

8. The method of claim 7, further comprising injecting H2 in an amount that is between 50% to 90% of the total gas flow.

9. An apparatus for selective oxidation of silicon on a substrate in the presence of other materials, comprising:

a vacuum enclosure;

a substrate pedestal situated within the enclosure;

a plasma generation region;

a conduit enabling radical flow from the plasma generation region to the vacuum enclosure;

a gas source coupled to the plasma generation region; and

a steam source coupled to the plasma generation region.

10. The apparatus of claim 9, further comprising a baffle situated between the vacuum enclosure and the plasma generation region, the baffle substantially preventing ions from reaching a substrate positioned on the substrate pedestal.

11. The apparatus of claim 9, further comprising a UV source configured for illuminating a substrate positioned on the substrate pedestal.

12. The apparatus of claim 11, wherein the UV source comprises an optical baffle situated between the vacuum enclosure and the plasma generation region, so as to control the amount of illumination from the plasma that reaches the substrate.

13. An apparatus for selective oxidation of silicon on a substrate in the presence of other materials, comprising:

a vacuum enclosure;

a substrate pedestal situated within the enclosure;

a plasma generation region, the plasma generation region comprising an RF transparent wall, an electrostatic shield provided about the wall, and an inductive coil provided about the shield;

a conduit enabling radical flow from the plasma generation region to the vacuum enclosure;

a gas source coupled to the plasma generation region.

14. The apparatus of claim 13, further comprising a steam source coupled to the plasma generation region.

15. The apparatus of claim 13, further comprising a baffle situated between the vacuum enclosure and the plasma generation region, the baffle preventing ions from reaching a substrate positioned on the substrate pedestal.

16. A method for selective oxidation of silicon on a substrate in the presence of tungsten, comprising:

placing the substrate in a vacuum processing chamber;

generating a plasma remotely from the substrate, such that charged particles from the plasma are substantially prevented from reaching the substrate;

injecting into the plasma H2 and at least one of O2 gas or H2O steam;

providing flow path for radicals from the plasma to reach the substrate.

17. The method of claim 16, comprising injecting into the plasma O2 gas in an amount such that the concentration of H2 to total gas flow is between 60% to 85%.

18. The method of claim 16, comprising injecting into the plasma H2O steam in an amount such that the concentration of H2 to total gas flow is between 50% to 90%.