Thermal oxidation of silicon using ozone

• US 7,972,441 B2
• Filed: 04/05/2005
• Issued: 07/05/2011
• Est. Priority Date: 04/05/2005
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Czarnik, Cory, Achutharaman, Vedapuram, Yokota, Yoshitaka, Ramamurthy, Sundar, Olsen, Christopher, Behdjat, Mehran
• Primary Examiner(s): Kackar; Ram N
• Assistant Examiner(s): Chandra; Satish
• Application Number:
  US11/099,082
• Publication Number:
  US 20060223315A1
• Time in Patent Office: 2,282 Days
• Field of Search: 118/715, 118/724, 118/725, 291/390, 291/405, 291/411, 392/416, 219/390, 219/405, 219/411, 438/769, 438/770
• US Class Current: 118/715
• CPC Class Codes: H01L 21/0214 the material being a silicon oxynitride, e.g. SiON or SiON:H
• CPC Class Codes: H01L 21/02238 silicon in uncombined form, i.e. pure silicon
• CPC Class Codes: H01L 21/02249 formation by combined oxidation and nitridation performed simultaneously
• CPC Class Codes: H01L 21/02255 formation by thermal treatment H01L21/02252 takes precedence; after treatment of an insulating film H01L21/3105 and subgroups
• CPC Class Codes: H01L 21/31658 by thermal oxidation, e.g. of SiGe
• CPC Class Codes: H01L 21/31662 of silicon in uncombined form
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/67115 mainly by radiation

Abstract

A method and apparatus for oxidizing materials used in semiconductor integrated circuits, for example, for oxidizing silicon to form a dielectric gate. An ozonator is capable of producing a stream of least 70% ozone. The ozone passes into an RTP chamber through a water-cooled injector projecting into the chamber. Other gases such as hydrogen to increase oxidation rate, diluent gas such as nitrogen or O₂, enter the chamber through another inlet. The chamber is maintained at a low pressure below 20 Torr and the substrate is advantageously maintained at a temperature less than 800° C. Alternatively, the oxidation may be performed in an LPCVD chamber including a pedestal heater and a showerhead gas injector in opposition to the pedestal.

Claims

1. A substrate oxidizing apparatus, comprising:

a vacuum chamber having sidewalls arranged about a central axis;

a rotatable support within the vacuum chamber for supporting a substrate in a first plane perpendicular to the central axis and rotating the substrate in an angular direction about the central axis, the substrate having a pre-existing surface layer to be oxidized to form an oxide layer on the substrate and the central axis passing through the substrate;

a heat source capable of heating the substrate to an elevated oxidizing temperature;

a source of hydrogen gas conveying the hydrogen gas into the chamber only through a single first gas port in the sidewalls, extending in a second plane perpendicular to the central axis, and directing the hydrogen gas perpendicularly to the central axis and towards a central region of the substrate;

an ozonator receiving a flow of oxygen gas, forming an electrically coupled plasma selected from one of a capacitively coupled plasma and an inductively coupled plasma, and capable of producing an ozone-containing gas, an output of the ozonator conveying ozone of the ozone-containing gas into the vacuum chamber through only a single second gas port in the sidewalls, extending in the second plane, and directing the ozone-containing gas perpendicularly to the central axis and towards the central region of the substrate to oxidize the layer in conjunction with the hydrogen gas; and

a pump port in the sidewalls for evacuating the vacuum chamber;

wherein the second gas port is angularly displaced in the second plane from the first gas port along a circumference about the central axis by an angular displacement of between 15° and

115°

to thereby in conjunction with the rotating support delay reaction of the ozone-containing gas and the hydrogen gas conveyed into the chamber by the first and second gas ports;

wherein said ozonator is capable of producing at least 30% ozone in the ozone-containing gas;

wherein a fluid cooled injector incorporated into the second gas port and extending from the sidewalls along an injector axis perpendicular to the central axis and configured to inject the ozone-containing gas toward the substrate from a distal end of the injector.

2. The oxidizing apparatus of claim 1, wherein the oxidizing temperature is at least 400°

C.

3. The apparatus of claim 1 wherein said ozonator is capable of producing at least 50% ozone.

4. The apparatus of claim 3, wherein said ozonator is capable of producing at least 90% ozone.

5. The apparatus of claim 1, wherein the angular displacement is along the angular direction.

6. The apparatus of claim 1, wherein the angular separation is 90°

.

7. The apparatus of claim 1, wherein the heat source includes a plurality of incandescent lamps directing radiation toward the substrate parallel to the central axis.