Low temperature silicon oxide conversion
A method of forming a silicon oxide layer is described. The method first deposits a silicon-nitrogen-and-hydrogen-containing (polysilazane) film by radical-component chemical vapor deposition (CVD). The polysilazane film is converted to silicon oxide by exposing the polysilazane film to humidity at low substrate temperature. The polysilazane film may also be dipped in a liquid having both oxygen and hydrogen, such as water, hydrogen peroxide and or ammonium hydroxide. These conversion techniques may be used separately or in a sequential combination. Conversion techniques described herein hasten conversion, produce manufacturing-worthy films and remove the requirement of a high temperature oxidation treatment. An ozone treatment may precede the conversion technique(s).
1. A method of forming a silicon oxide layer on a substrate, the method comprising:
forming a silicon-nitrogen-and-hydrogen-containing layer by:
flowing an unexcited precursor into a remote plasma region to produce a radical-precursor,
combining a silicon-containing precursor with the radical-precursor in a plasma-free substrate processing region, and
depositing the silicon-nitrogen-and-hydrogen-containing layer on the substrate;
curing the silicon-nitrogen-and-hydrogen-containing layer in an ozone-containing atmosphere to convert the silicon-nitrogen-and-hydrogen-containing layer to a silicon-and-oxygen-containing layer; and
exposing the silicon-and-oxygen-containing layer to a humid atmosphere having at least 50% relative humidity to convert the silicon-and-oxygen-containing layer to a silicon oxide layer, wherein the substrate temperature is greater than 25° C. and less than 100° C. during the exposing operation.
2. The method of claim 1 wherein the humid atmosphere has at least 75% relative humidity.
3. The method of claim 1 wherein the substrate temperature is greater than 125° C. and less than 225° C. during the curing operation.
4. The method of claim 1 wherein the operation of exposing the silicon-and-oxygen-containing layer to the humid atmosphere lasts less than five hours.
5. The method of claim 1 wherein the operation of exposing the silicon-and-oxygen-containing layer to the humid atmosphere lasts less than two hours.
6. The method of claim 1 wherein the silicon oxide layer consists essentially of silicon and oxygen.
7. The method of claim 1 wherein the silicon-nitrogen-and-hydrogen-containing layer is flowable during deposition.
8. The method of claim 1 wherein the substrate is patterned and has a trench having a width of about 50 nm or less.
9. The method of claim 1 wherein the silicon-containing precursor and the silicon-nitrogen-and-hydrogen-containing layer are each carbon-free.
10. The method of claim 1 wherein the unexcited precursor comprises at least one of N 2 H 4 , NH 3 , N 2 and H 2 .
11. The method of claim 1 wherein the silicon-containing precursor comprises N(SiH 3 ) 3 .