Apparatus and Methods for Cyclical Oxidation and Etching
Apparatus and methods for the manufacture of semiconductor devices suitable for narrow pitch applications and methods of fabrication thereof are described herein. Disclosed are various single chambers configured to form and/or shape a material layer by oxidizing a surface of a material layer to form an oxide layer; removing at least some of the oxide layer by an etching process; and cyclically repeating the oxidizing and removing processes until the material layer is formed to a desired shape. In some embodiments, the material layer may be a floating gate of a semiconductor device.
1 . An apparatus for processing a substrate comprising:
a process chamber having a substrate support disposed therein to support a substrate;
a temperature control system to control the temperature of a substrate supported on the substrate support at a first temperature below about 100° C.;
a gas source in fluid communication with the chamber to deliver at least an oxygen-containing gas, an inert gas and an etching gas into the process chamber;
a plasma source in fluid communication with the process chamber to energize at least one of the oxygen-containing gas and the etching gas to form at least one of an oxidizing plasma or an etching plasma; and
a heat source to heat the substrate to a second temperature greater than the first temperature.
2 . The apparatus of claim 1 , wherein the chamber is configured to deliver one of the etching gas and the etching plasma to the process chamber when the temperature of the substrate is at the first temperature and to deliver one of the oxidizing gas and oxidizing plasma when the temperature of the substrate is at the second temperature.
3 . The apparatus of claim 2 , wherein the second temperature is in the range of about 200° C. and 1000° C.
4 . The apparatus of claim 3 , wherein the chamber is configured to perform an etch process on a material layer on the substrate, at least a portion of the etch process being performed at the first temperature.
5 . The apparatus of claim 4 , wherein the etch process comprises a dry etch process and the etching gas comprises a fluorine-containing gas in fluid communication with the plasma source to form an etching plasma.
6 . The apparatus of claim 5 , wherein the gas source further includes nitrogen gas in communication with a plasma source.
7 . The apparatus of claim 4 , wherein the temperature control system includes a cooling system to perform at least a portion of the etching process at a temperature below about 50° C. and the apparatus is configured to cycle between the first temperature and second temperature and to cyclically perform an etching process and on oxidation process on the material layer in less than about three minutes.
8 . The apparatus of claim 7 , wherein the cooling system is configured to reduce the temperature of the substrate to a temperature in the range of about 25° C. to about 35° C.
9 . The apparatus of claim 1 , wherein the apparatus is configured to shape a material layer on the substrate, the material layer having a desired shape with a first width proximate a base of the desired shape that is substantially equivalent to a second width proximate a top of the desired shape, wherein the first and second width of the desired shape is between about 1 to about 30 nanometers.
10 . The apparatus of claim 1 , wherein the oxidation process comprises rapid thermal oxidation, radical oxidation, plasma oxidation, chemical oxidation, or photochemical oxidation and the etching process comprises at least one of wet or dry chemical etch, reactive ion etch, or plasma etch.
11 . A method of shaping a material layer on a substrate comprising:
(a) processing a surface of a material layer to form an oxide or nitride-containing layer in a process chamber;
(b) terminating formation of the oxide or nitride-containing layer;
(c) removing at least some of the oxide or nitride-containing layer by an etching process in the same process chamber as in (a); and
(d) repeating (a) through (c) in the same process chamber until the material layer is formed to a desired shape.
12 . The method of claim 11 wherein oxidizing the material layer to form the oxide layer is performed by at least one of wet or dry rapid thermal oxidation, radical oxidation, plasma oxidation, wet or dry chemical oxidation, or photochemical oxidation and the etch process comprises at least one of wet or dry chemical etch, reactive ion etch, or plasma etch.
13 . The method of claim 11 , wherein the material layer is formed into the desired shape having a first width proximate a base of the desired shape that is substantially equivalent to a second width proximate a top of the desired shape and the desired shape has an aspect ratio of between about 0.5 to about 20 nanometers.
14 . The method of claim 13 , wherein the first and second width of the desired shape is between about 1 to about 30 nanometers.
15 . An apparatus for performing a cyclical oxidation and etching process on a material layer, comprising:
a processing chamber having a plurality of walls defining a processing region within the processing chamber including a substrate support to hold a substrate having a material layer within the processing region;
an oxygen-containing gas supply, an inert gas supply and an etching gas supply in fluid communication with the processing chamber to deliver the oxygen-containing gas, the inert gas and the etching gas into the process chamber;
a remote plasma source in fluid communication with the process chamber and the etching gas to form an etching plasma remotely from the chamber and conduit to deliver the etching plasma into the chamber;
a heating system to heat the substrate within the chamber to a first temperature greater than about 100° C.;
a cooling system to cool the substrate within the chamber to a second temperature below the first temperature; and
a control system to cycle the substrate within the chamber between the first temperature the second temperature.
16 . The apparatus of claim 15 , wherein the apparatus is configured to conduct an oxidation process substantially only by thermal oxidation.
17 . The apparatus of claim 15 , wherein the apparatus is configured to conduct oxidation by a rapid thermal oxidation process and the heating system comprises a rapid thermal processing chamber comprising a radiant heat source and a reflector plate, wherein the substrate support is disposed between the reflector plate and the radiant heat source.
18 . The apparatus of claim 17 , wherein the remote plasma source is in fluid communication with an etching gas comprising a fluorine-containing gas.
19 . The apparatus of claim 18 , wherein the chamber includes at least one elongate lance to deliver etching plasma products into the chamber.
20 . The apparatus of claim 15 , wherein the cooling system comprises a reflector plate incorporating gas distribution outlets to distribute a gas evenly over a substrate to allow rapid and controlled heating and cooling of the substrate.
21 . The apparatus of claim 20 , wherein the apparatus comprises lift pins adapted to selectively contact and support the substrate to move the substrate towards and away from the reflector plate.
22 . The apparatus of claim 21 , wherein the apparatus includes a stator assembly magnetically coupled to the substrate support to move the substrate being processed towards and away from the plate.
23 . The apparatus of claim 22 , wherein at least one of the stator assembly and lift pins cooperate with the cooling system to move the substrate support closer to the reflector plate to cool the substrate.
24 . The apparatus of claim 15 , wherein the control system, the heating system and the cooling system are configured to cycle between the first temperature and second temperature within a time period of less than about three minutes.
25 . The apparatus of claim 15 , wherein the apparatus is configured to conduct an oxidation process by photochemical oxidation.