Spacer material modification to improve K-value and etch properties

1. A method for performing a spacer etch process utilizing a post deposition treatment, the method comprising:

conformally applying a spacer material over a gate structure on a substrate, the spacer material having an initial K-value;

treating an exposed surface of said spacer material to an oxygen-containing plasma environment to form a spacer oxidation layer; and

performing one or more spacer etch process sequences to partially remove said spacer oxidation layer and spacer material from said gate structure and said substrate, while retaining a sidewall spacer positioned along a sidewall of said gate structure resulting in a bi-layer spacer with the spacer oxidation layer on the outer side of the spacer yielding a spacer with a final K-value; and

controlling spacer etch variables in order to achieve a target difference of initial K-value to final K-value of the spacer;

wherein the spacer material comprises silicon nitride (Si x N z ), silicon carbide (Si x C y ), or silicon carbonitride (Si x C y N z ); or silicon oxycarbonnitride (Si x OC y N z ) and wherein the difference between the initial K-value and the final K-value is 5 to 10% of the initial K-value; and

wherein the spacer material conformally applied over the gate structure has a thickness less than or equal to 10 nanometers (nm), the oxygen-containing environment contains an oxygen-containing plasma, the oxygen-containing plasma comprises O, O 2 , O 3 , CO, CO 2 , NO, N 2 O, or NO 2 , or any combination of two or more thereof, and the oxygen containing plasma has a flow rate of 300 to 400 sccm.

2. The method of claim 1 , wherein said performing one or more spacer etch process sequences comprises:

introducing an etching process composition containing any fluorocarbon gas CxHyFz combined with an oxidant such as O2 or CO2 or a reductant such as H2 and diluent such as Ar or He to a plasma processing system;

setting a pressure in said plasma processing system in a range of 5 to 20 mTorr;

setting a temperature for said plasma processing system in a range of 20 to 100° C.;

forming a first etching plasma from said etching process composition; and

exposing said substrate to said etching plasma for a time period of 60 to 120 seconds.

3. The method of claim 2 , wherein said performing one or more etching processes further comprises:

forming said etching plasma by coupling electromagnetic (EM) radiation from a radial line slot antenna (RLSA) to said etching process composition; and

applying an electrical bias to said substrate by coupling radio frequency (RF) power to a substrate holder upon which said substrate rests;

wherein said electrical bias is in the range of 0 to −25 W.

4. The method of claim 3 , wherein said forming said etching plasma comprises coupling electromagnetic (EM) energy at a microwave frequency in a desired EM wave mode to said etching plasma by generating a surface wave on a plasma surface of an EM wave launcher adjacent said etching plasma, said EM wave launcher comprises a slot antenna having a plurality of slots formed there through configured to couple said EM energy from a first region above said slot antenna to a second region below said slot antenna; and/or wherein said spacer material comprises SiON, SiOCN, and/or SiBCN.

5. A method for performing a spacer etch process utilizing a post spacer treatment, the method comprising:

conformally applying a spacer material over a gate structure on a substrate, the spacer material having an initial K-value;

performing one or more spacer etch process sequences to partially remove said spacer material from said gate structure and said substrate, while retaining a sidewall spacer positioned along a sidewall of said gate structure; and

treating an exposed surface of said spacer material and substrate to an oxygen containing environment to form a spacer oxidation layer yielding a spacer with a final K-value;

controlling spacer etch variables in order to achieve a target difference of initial K-value to final K-value of the spacer;

wherein the spacer material comprises silicon nitride (SixNz), silicon carbide (Si x C y ), or silicon carbonitride (Si x C y N z ) or silicon oxycarbonnitride (Si x OC y N z ); and

wherein the difference between the initial K-value and the final K-value is 5 to 10% of the initial K-value; and

wherein the spacer material conformally applied over the gate structure has a thickness less than or equal to 10 nanometers (nm), the oxygen-containing environment contains an oxygen-containing plasma, the oxygen-containing plasma comprises O, O 2 , O 3 , CO, CO 2 , NO, N 2 O, or NO 2 , or any combination of two or more thereof, and the oxygen containing plasma has a flow rate of 300 to 400 sccm.

6. The method of claim 5 , wherein said performing one or more spacer etch process sequences comprises:

introducing an etching process composition containing any fluorocarbon gas CxHyFz combined with an oxidant such as O2 or CO2 or a reductant such as H2 and diluent such as Ar or He to a plasma processing system;

setting a pressure in said plasma processing system at or less than about 5 to 20 mTorr;

setting a temperature for said plasma processing system at a range of 20 to 100° C.;

forming a first etching plasma from said etching process composition; and

exposing said substrate to said etching plasma for a time period of 60 to 120 seconds.

7. The method of claim 6 , wherein said performing one or more etching processes further comprises:

forming said etching plasma by coupling electromagnetic (EM) radiation from a radial line slot antenna (RLSA) to said etching process composition; and

applying an electrical bias to said substrate by coupling radio frequency (RF) power to a substrate holder upon which said substrate rests;

wherein said electrical bias is in the range of 0 to −25 W.

8. A method for performing a spacer etch process utilizing a post partial contact etch and oxidation treatment, comprising:

conformally applying a spacer material over a gate structure on a substrate, the spacer material having an initial K-value;

performing one or more spacer etch process sequences to partially remove said spacer material from said gate structure and said substrate, while retaining a sidewall spacer positioned along a sidewall of said gate structure; and

performing one or more deposition process sequences to generate an oxide fill layer above the gate structure;

performing a partial-contact etch sequence to remove the oxide fill layer above a portion of the gate structure;

treating an exposed surface of said portion of the gate structure to an oxygen-containing environment to form a spacer oxidation layer;

performing a finish-contact etch sequence to remove remaining oxide fill layer above said portion of the gate structure, yielding a spacer with a final K-value; and

controlling spacer etch variables in order to achieve a target difference of initial K-value to final K-value of the spacer;

wherein the spacer material comprises silicon nitride (Si x N z ), silicon carbide (Si x C y ), or silicon carbonitride (Si x C y N z ) or silicon oxycarbonnitride (Si x OC y N z ); and

wherein the difference between the initial K-value and the final K-value is 5 to 10% of the initial K-value; and/or wherein the spacer material conformally applied over the gate structure has a thickness less than or equal to 10 nanometers (nm), the oxygen-containing environment contains an oxygen-containing plasma, the oxygen-containing plasma comprises O, O 2 , O 3 , CO, CO 2 , NO, N 2 O, or NO 2 , or any combination of two or more thereof, the oxygen containing plasma has a flow rate of 300 to 400 sccm; and

wherein said performing one or more spacer etch process sequences comprises:

introducing an etching process composition containing any fluorocarbon gas CxHyFz combined with an an oxidant such as O2 or CO2 or a reductant such as H2 and diluent such as Ar or He setting a pressure in said plasma processing system at or less than about 5 to 20 mTorr;

setting a temperature for said plasma processing system at a range of 20 to 100° C.;

forming a first etching plasma from said etching process composition; and

exposing said substrate to said etching plasma for a time period of 60 to 120 seconds; or

wherein said performing one or more etching processes further comprises:

forming said etching plasma by coupling electromagnetic (EM) radiation from a radial line slot antenna (RLSA) to said etching process composition; and

applying an electrical bias to said substrate by coupling radio frequency (RF) power to a substrate holder upon which said substrate rests;

wherein said electrical bias is in the range of 0 to −25 W.

9. The method of claim 8 , wherein the target difference between the initial K-value and the final K-value is 2 to 16% of the initial K-value.

10. A method for performing a spacer etch process utilizing a post deposition and nitridation treatment, the method comprising:

conformally applying a spacer material over a gate structure on a substrate;

treating an exposed surface of said spacer material to an nitrogen-containing environment to form a spacer nitridation layer; and

performing one or more spacer etch process sequences to partially remove said spacer nitridation layer and spacer material from said gate structure and said substrate, while retaining a sidewall spacer positioned along a sidewall of said gate structure resulting in a bi-layer spacer with the spacer nitridation layer on the outside of the spacer; and

controlling spacer etch variables in order to achieve target wet resistance to wet etch treatment liquids;

wherein the spacer material comprises SiON, SiOCN, or SiBCN.

11. The method of claim 10 , wherein the spacer material conformally applied over the gate structure has a thickness less than or equal to 10 nanometers (nm), the nitrogen-containing plasma has a flow rate of 300 to 400 sccm.

12. The method of claim 11 , wherein said performing one or more spacer etch process sequences comprises:

introducing an etching process composition containing any fluorocarbon gas CxHyFz combined with an oxidant such as O2 or CO2 or a reductant such as H2 and diluent such as Ar or He to a plasma processing system;

setting a pressure in said plasma processing system at or less than about 5 to 20 mTorr;

setting a temperature for said plasma processing system at a range of 20 to 100° C.;

forming an etching plasma from said etching process composition; and

exposing said substrate to said etching plasma for a time period of 60 to 120 seconds.

13. The method of claim 12 , wherein said performing one or more etching processes further comprises:

forming said etching plasma by coupling electromagnetic (EM) radiation from a radial line slot antenna (RLSA) to said etching process composition; and

applying an electrical bias to said substrate by coupling radio frequency (RF) power to a substrate holder upon which said substrate rests;

wherein said electrical bias is in the range of 0 to −25 W.

14. A method for performing a spacer etch process utilizing a post spacer reaction-in etch (RIE) and nitridation treatment, the method comprising:

conformally applying a spacer material over a gate structure on a substrate;

performing one or more plasma spacer etch process sequence to partially remove said spacer material from said gate structure and said substrate, while retaining a sidewall spacer positioned along a sidewall of said gate structure; and

treating an exposed surface of said gate structure to an nitrogen-containing environment to form a spacer nitridation layer; and

controlling spacer etch variables in order to achieve a target wet resistance increase of the spacer to wet etch treatment liquid;

wherein the spacer material comprises SiON, SiOCN, or SiBCN.

15. The method of claim 14 :

wherein the spacer material conformally applied over the gate structure has a thickness less than or equal to 10 nanometers (nm), the nitrogen-containing plasma has a flow rate of 300 to 400 sccm;

wherein the nitrogen containing environment comprises ammonia, nitrogen, and/or hydrazine; and/or

wherein the target wet resistance increase of the spacer to wet etch treatment liquids is 0.25 of the normalized etch rate of thermal oxide.

16. The method of claim 15 , wherein said performing one or more spacer etch process sequences comprises:

introducing an etching process composition containing any fluorocarbon gas CxHyFz combined with an oxidant such as O2 or CO2 or a reductant such as H2 and diluent such as Ar or He to a plasma processing system;

setting a pressure in said plasma processing system at or less than about 5 to 20 mTorr;

setting a temperature for said plasma processing system at a range of 20 to 100° C.;

forming an etching plasma from said etching process composition; and

exposing said substrate to said etching plasma for a time period of 60-120 seconds.

17. The method of claim 15 , wherein said performing one or more etching processes further comprises:

forming said etching plasma by coupling electromagnetic (EM) radiation from a radial line slot antenna (RLSA) to said etching process composition; and

applying an electrical bias to said substrate by coupling radio frequency (RF) power to a substrate holder upon which said substrate rests, wherein said electrical bias is in the range of 0 to −25 W.