Flowable silicon—carbon—oxygen layers for semiconductor processing
Methods are described for forming a dielectric layer on a patterned substrate. The methods may include combining a silicon-and-carbon-containing precursor and a radical oxygen precursor in a plasma free substrate processing region within a chemical vapor deposition chamber. The silicon-and-carbon-containing precursor and the radical oxygen precursor react to deposit a flowable silicon-carbon-oxygen layer on the patterned substrate. The resulting film possesses a low wet etch rate ratio relative to thermal silicon oxide and other standard dielectrics.
1. A method of forming a silicon-carbon-oxygen layer on a patterned substrate, the method comprising:
transferring the patterned substrate into a substrate processing region of a substrate processing chamber;
flowing an oxygen-containing precursor into a remote plasma region while igniting a remote plasma to form a radical oxygen precursor;
flowing a silicon-and-carbon-containing precursor into a substrate processing region without first passing the silicon-and-carbon-containing precursor through a plasma, wherein the silicon-and-carbon-containing precursor has two distinct silicon atoms separated by at least one carbon atom;
flowing the radical oxygen precursor into the substrate processing region;
combining the silicon-and-carbon-containing precursor and the radical oxygen precursor in the substrate processing region to form a silicon-carbon-oxygen layer on the patterned substrate, wherein the silicon-carbon-oxygen layer is flowable during formation; and
curing the silicon-carbon-oxygen layer, wherein the formed silicon-carbon-oxygen layer comprises an atomic percentage of carbon content greater than 5%, and wherein the cured silicon-carbon-oxygen layer is characterized by a wet etch rate ratio (WERR) of less than 0.5 compared to thermal silicon oxide in a dilute HF solution.
2. The method of claim 1 , wherein the silicon-and-carbon-containing precursor comprises 1,3,5-trisilapentane, 1,4,7-trisilaheptane, disilacyclobutane, trisilacyclohexane, 1,4-disilabutane, disilacyclohexane, disilacyclopentane, or disilapropane.
3. The method of claim 1 , wherein the silicon-and-carbon-containing precursor comprises:
(i) SiR 4 , Si 2 R 6 , Si 3 R 8 , Si 4 R 10 , or Si 5 R 12 , wherein each R group is independently hydrogen (—H) or a saturated or unsaturated alkyl group;
(ii) a silylalkane or silylalkene having the formula R 3 Si—[CH 2 ] n —SiR 3 , wherein n may be an integer from 1 to 10, and each of the R groups are independently a hydrogen (—H), or a saturated or unsaturated alkyl group;
(iii) a silylalkane or silylalkene having the formula R 3 Si—[CR 2 ] x —SiR 2 —[CR 2 ] y —SiR 3 , wherein x and y are independently an integer from 1 to 10, and each of the R groups are independently a hydrogen (—H), or a saturated or unsaturated alkyl group;
(iv) a silacycloalkane or silacycloalkene selected from the group consisting of silacyclopropanes, silacyclobutanes, silacyclopentanes, silacyclohexanes, silacycloheptanes, silacyclooctanes, silacyclononanes, silacyclopropenes, silacyclobutenes, silacyclopentenes, silacyclohexenes, silacycloheptenes, silacyclooctenes, and silacyclononenes;
(v) H 4-x-y CX y (SiR 3 ) x , where x is 1, 2, 3, or 4, y is 0, 1, 2 or 3, each X is independently a hydrogen or halogen (e.g., F, Cl, Br), and each R is independently a hydrogen (—H) or an alkyl group;
(vi) (SiR 3 ) x C═C(SiR 3 ) x , where x is 1 or 2, and each R is independently a hydrogen (—H) or an alkyl group; or
(vii) R—[(CR′ 2 ) x —(SiR″ 2 ) y —(CR′ 2 ) z ] n —R, wherein each R, R′, and R″ are independently a hydrogen, an alkyl group, an unsaturated alkyl group, a silane group, or
(viii) [(CH 2 ) x1 —(SiH 2 ) y1 —(CH 2 ) z1 ] n1 —R′″ wherein x1, y1 and z1 are independently a number from 0 to 10, and n1 is a number from 0 to 10, wherein R′″ is a hydrogen, alkyl group, unsaturated alkyl group, or silane group,
and wherein x, y and z are independently a number from 0 to 10, and n is a number from 0 to 10.
4. The method of claim 1 , wherein the silicon-and-carbon-containing precursor comprises one of 1,3,5-trisilapentane or 1,4,7-trisilaheptane.
5. The method of claim 1 , wherein the oxygen-containing precursor comprises oxygen (O 2 ) or ozone (O 3 ).
6. The method of claim 1 , wherein the remote plasma region is a remote plasma system external to but fluidly coupled to the substrate processing chamber.
7. The method of claim 1 , wherein the remote plasma region is a compartment within the substrate processing chamber but separated from the substrate processing region by a showerhead.
8. The method of claim 1 , wherein the remote plasma region is excited using an inductively-coupled plasma or a capacitively-coupled plasma.
9. The method of claim 1 , wherein a temperature of the patterned substrate is less than 400° C. during formation of the silicon-carbon-oxygen layer.
10. The method of claim 1 , wherein the silicon-and-carbon-containing precursor is nitrogen-free.
11. The method of claim 1 , wherein the silicon-carbon-oxygen layer is nitrogen-free.
12. The method of claim 1 , wherein the silicon-and-carbon-containing precursor consists of silicon, carbon and hydrogen.
13. The method of claim 1 , wherein the silicon-carbon-oxygen layer consists of silicon, carbon, oxygen and hydrogen.
14. The method of claim 1 , wherein the two distinct silicon atoms are separated by at least two covalently carbon atoms bonded in series.
15. The method of claim 1 , wherein the two distinct silicon atoms are separated by only carbon atoms.
16. The method of claim 1 , wherein the two distinct silicon atoms are separated by carbon atoms but no nitrogen atoms.
17. The method of claim 1 , wherein the two distinct silicon atoms are separated by carbon atoms but no oxygen atoms.
18. A method of forming a silicon-carbon-oxygen layer on a patterned substrate, the method comprising:
transferring the patterned substrate into a substrate processing region of a substrate processing chamber;
flowing an oxygen-containing precursor into a remote plasma region while igniting a remote plasma to form a radical oxygen precursor, wherein the plasma is devoid of nitrogen;
flowing a silicon-and-carbon-containing precursor into a substrate processing region without first passing the silicon-and-carbon-containing precursor through a plasma, wherein the silicon-and-carbon-containing precursor consists of hydrogen and two distinct silicon atoms separated by at least one carbon atom;
flowing the radical oxygen precursor into the substrate processing region, wherein each of the flowing operations are devoid of nitrogen;
combining the silicon-and-carbon-containing precursor and the radical oxygen precursor in the substrate processing region to form a silicon-carbon-oxygen layer on the patterned substrate, wherein the silicon-carbon-oxygen layer is flowable during formation; and
curing the silicon-carbon-oxygen layer, wherein the formed silicon-carbon-oxygen layer comprises an atomic percentage of carbon content greater than 10%, wherein the formed layer is devoid of nitrogen, and wherein the cured silicon-carbon-oxygen layer is characterized by a wet etch rate ratio (WERR) of less than 0.1 compared to thermal silicon oxide in a dilute HF solution.