Precursors and flowable CVD methods for making low-K films to fill surface features
A method for depositing a silicon-containing film, the method comprising: placing a substrate comprising at least one surface feature into a flowable CVD reactor which is at a temperature of from about −20° C. to about 100° C.; increasing pressure in the reactor to at least 10 torr; and introducing into the reactor at least one silicon-containing compound having at least one acetoxy group to at least partially react the at least one silicon-containing compound to form a flowable liquid oligomer wherein the flowable liquid oligomer forms a silicon oxide coating on the substrate and at least partially fills at least a portion of the at least one surface feature. Once cured, the silicon oxide coating has a low k and excellent mechanical properties.
1. A method for depositing a silicon-containing film, the method comprising:
placing a substrate comprising at least one surface feature into a reactor which is at a temperature of from about −20° C. to about 100° C.;
introducing into the reactor at least one oxygen source;
introducing into the reactor at least one silicon-containing compound having at least one acetoxy group, wherein the at least one silicon-containing compound is selected from the group consisting of:
I(a) acyloxysilanes with a formula of (RCOO) m R 1 n SiH p wherein R is selected from hydrogen, a linear or branched C 1 to C 6 alkyl group; R 1 is selected from a linear or branched C 1 to C 6 alkyl group, a linear or branched C 2 to C 6 alkenyl group, a linear or branched C 2 to C 6 alkynyl group; m=1, 2, or 3; n=1, 2, or 3; p=0, 1, or 2; and m+n+p=4;
increasing pressure in the reactor to at least 10 torr; and
providing an in-situ plasma or remote plasma source to the reactor to at least partially react the at least one silicon-containing compound to form a flowable liquid oligomer wherein the flowable liquid oligomer forms a coating on the substrate and at least partially fills at least a portion of the at least one surface feature.
2. The method of claim 1 wherein the pressure in the reactor is 12 Torr.
3. The method of claim 1 wherein the plasma is in-situe plasma.
4. The method of claim 1 further comprising a step of subjecting the coating to a thermal treatment at one or more temperatures between about 100° C. and about 1000° C. to densify at least a portion of the coating and form a hardened layer.
5. The method of claim 4 further comprising a step of exposing the hardened layer to energy selected from the group consisting of a plasma, infrared light, a chemical treatment, an electron beam, and UV light.
6. The method of claim 5 wherein the recited steps define one cycle for the method and the cycle is repeated until a desired thickness of the silicon-containing film is obtained.
7. The method of claim 1 wherein the at least one silicon-containing compound having at least one acetoxy group comprises diacetoxydimethylsilane.
8. The method of claim 1 wherein the acyloxysilane having the Formula I(a) is selected from the group consisting of:
wherein R is selected from the group consisting of methyl, ethyl, n-propyl, iso-propyl, tert-butyl, n-butyl, sec-butyl, and iso-butyl; and R 1 is selected from the group consisting of methyl, ethyl, vinyl, allyl, and ethynyl.
9. The method of claim 1 wherein the silicon containing film has a dielectric constant of between 2.8 and 3.6 as determined by Capacitence-Voltage measurements, and a porosity of <10% as measured by Ellipsometric Porosimetry.