Cureable formulations for forming low-k dielectric silicon-containing films using polycarbosilazane

Abstract

Disclosed are silicon and carbon containing film forming compositions comprising a polycarbosilazane polymer or oligomer formulation that consists of silazane-bridged carbosilane monomers, the carbosilane containing at least two —SiH.sub.2— moieties, either as terminal groups (—SiH.sub.3R) or embedded in a carbosilane cyclic compound, wherein R is H, a C.sub.1-C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1-C.sub.6 linear, branched, or cyclic alkenyl- group, or combination thereof. Also disclosed are methods of forming a silicon and carbon containing film comprising forming a solution comprising a polycarbosilazane polymer or oligomer formulation and contacting the solution with the substrate via a spin-on coating, spray coating, dip coating, or slit coating technique to form the silicon and carbon containing film.

Claims

1. A reaction mixture for producing a film forming polycarbosilazane polymer or oligomer, the reaction mixture comprising carbosilanes and amines, wherein the carbosilanes contain at least two —SiH.sub.2— moieties, either as terminal groups (—SiH.sub.2R) or embedded in a carbosilane cyclic compound, wherein R is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkenyl-group, or combination thereof, and wherein the reaction mixture is capable of forming the film forming polycarbosilazane polymer or oligomer, wherein the reaction mixture further comprises a polysilane that contains more than two —SiH.sub.2R function groups, wherein R is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkenyl-group, or a combination thereof.

2. The reaction mixture of claim 1, wherein the film forming polycarbosilazane polymer or oligomer has a backbone that comprises Si—N units, Si—N—C.sub.n—N—Si units, Si—N—Si units or combinations thereof, wherein n≥1, wherein the backbone includes cross-linked Si—N units, Si—N—C.sub.n—N—Si units, or Si—N—Si units, branched Si—N units, Si—N—C.sub.n—N—Si units, or Si—N—Si units, or combinations thereof.

3. The reaction mixture of claim 1, wherein the carbosilane has the formula:
R.sup.1.sub.aSi[—(CH.sub.2).sub.b—SiH.sub.2R.sup.2].sub.c  (I) wherein R.sup.1, R.sup.2 are independently H, a C.sub.1 to C.sub.6 linear, branched or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched or cyclic alkenyl-group, or combination thereof; a=0 to 2; b=1 to 4; c=4-a; or
R.sup.3.sub.eC[—(CH.sub.2).sub.f—SiH.sub.2R.sup.4].sub.g  (II) wherein R.sup.3, R.sup.4 are independently H, a C.sub.1 to C.sub.6 linear, branched or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched or cyclic alkenyl-group, or combination thereof; e=0 to 2; f=0 to 3; g=4-e; or
[scaffold]-[—(CH.sub.2).sub.m—SiH.sub.2R.sup.5].sub.n  (III) wherein R.sup.5 is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched or cyclic alkenyl-group, or combination thereof; m=0 to 4; n=2 to 4; and the scaffold is a hydrocarbon scaffold; or
R.sup.6.sub.x-1,3,5-trisilacyclohexane  (IV) wherein R.sup.6 is a C.sub.1 to C.sub.6 linear, branched or cyclic alkyl- or alkenyl-group; x=0 to 3.

4. The reaction mixture of claim 3, wherein the hydrocarbon scaffold is a hydrocarbon scaffold including a C.sub.3 to C.sub.10 cyclic hydrocarbon scaffold containing silyl- group, —NH group, —O— ether group.

5. The reaction mixture of claim 1, wherein the carbosilane contains Si—C.sub.n—Si unit (n≥1) unit(s) or a 1,3,5-trisilacyclohexane (TSCH) backbone.

6. The reaction mixture of claim 1, wherein the carbosilane is selected from the group consisting of Si[—(CH.sub.2)—SiH.sub.3].sub.4, Si[—(CH.sub.2).sub.2—SiH.sub.3].sub.4, Si[—(CH.sub.2).sub.3—SiH.sub.3].sub.4, and Si[—(CH.sub.2).sub.4—SiH.sub.3].sub.4, R.sup.1Si[—(CH.sub.2)—SiH.sub.3].sub.3, R.sup.1Si[—(CH.sub.2).sub.2—SiH.sub.3].sub.3, R.sup.1Si[—(CH.sub.2).sub.3—SiH.sub.3].sub.3, and R.sup.1Si[—(CH.sub.2).sub.4—SiH.sub.3].sub.3, H.sub.3Si—CH.sub.2—SiH.sub.2—CH.sub.2—SiH.sub.3 (bis(silylmethyl)silane), H.sub.3Si—(CH.sub.2).sub.2—SiH.sub.2—(CH.sub.2).sub.2—SiH.sub.3 (bis(2-silylethyl)silane), H.sub.3Si—(CH.sub.2).sub.3—SiH.sub.2—(CH.sub.2).sub.3—SiH.sub.3 (bis(3-silylpropyl)silane), and H.sub.3Si—(CH.sub.2).sub.4—SiH.sub.2—(CH.sub.2).sub.4—SiH.sub.3 (bis(4-silylbutyl)silane), C[—SiH.sub.3].sub.4(tetrasilylmethane), C[—(CH.sub.2)—SiH.sub.3].sub.4(2,2-bis(silylmethyl)propane-1,3-diyl)bis(silane)), C[—(CH.sub.2).sub.2—SiH.sub.3].sub.4(3,3-bis(2-silylethyl)pentane-1,5-diyl)bis(silane)), and C[—(CH.sub.2).sub.3—SiH.sub.3].sub.4(4,4-bis(3-silylpropyl)heptane-1,7-diyl)bis(silane)), R.sup.1C[—SiH.sub.3].sub.3, R.sup.1C[—(CH.sub.2)—SiH.sub.3].sub.3, R.sup.1C[—(CH.sub.2).sub.2—SiH.sub.3].sub.3, and R.sup.1C[—(CH.sub.2).sub.3—SiH.sub.3].sub.3, H.sub.3Si—CH.sub.2—SiH.sub.3 (bisilylmethane), H.sub.3Si—(CH.sub.2).sub.5—SiH.sub.3 (1,5-disilylpentane)), and H.sub.3Si—(CH.sub.2).sub.7—SiH.sub.3 (1,7-disilylheptane)), 1,3-disilylcyclopentane, 1,2-disilylcyclopentane, 1,4-disilylcyclohexane, 1,3-disilylcyclohexane, 1,2-disilylcyclohexane, 1,3,5-trisilylcyclohexane and 1,3,5-trisilylbenzene, 2-Me-TSCH, 2-Et-TSCH, 2-iPr-TSCH, 2-nPr-TSCH, 2-nBu-TSCH, 2-tBu-TSCH, 2-sBu-TSCH, 2-iBu-TSCH, 2,4-Me.sub.2-TSCH, 2,4-Et.sub.2-TSCH, 2,4-iPr.sub.2-TSCH, 2,4-nPr.sub.2-TSCH, 2,4-nBu.sub.2-TSCH, 2,4-iBu.sub.2-TSCH, 2,4-tBu.sub.2-TSCH, 2,4-sBu.sub.2-TSCH, 2,4,6-Me.sub.3-TSCH, 2,4,6-Et.sub.3-TSCH, 2,4,6-iPr.sub.3-TSCH, 2,4,6-nPr.sub.3-TSCH, 2,4,6-nBu.sub.3-TSCH, 2,4,6-iBu.sub.3-TSCH, 2,4,6-tBu.sub.3-TSCH, 2,4,6-sBu.sub.3-TSCH, and combinations thereof, wherein R.sup.1 is H, a C.sub.1-C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1-C.sub.6 linear, branched, or cyclic alkenyl-group, or combinations thereof.

7. The reaction mixture of claim 1, wherein the carbosilane is 1,3,5-trisilapentane (CAS No.: 5637-99-0) or 1,3,5-trisilacyclohexane (CAS No.: 291-27-0).

8. The reaction mixture of claim 1, wherein the amine is selected from one or more of ammonia, amidine, hydrazine, hydroxylamine, monoalkylamine, diamines including ethylene diamine, or polyamines, which polyamines contain at least two N—H bonds either on the same nitrogen atom or on separate nitrogen atoms.

9. The reaction mixture of claim 1, wherein the polysilane is selected from one or more of neopentasilane (Si(SiH.sub.3).sub.4), n-tetrasilane (SiH.sub.3(SiH.sub.2).sub.2SiH.sub.3), 2-silyl-tetrasilane ((SiH.sub.3).sub.2SiHSiH.sub.2SiH.sub.3), trisilylamine (N(SiH.sub.3).sub.3), or trisilyamine derivatives.

10. A method of forming a silicon and carbon containing film on a substrate, the method comprising the steps of: producing a film forming polycarbosilazane polymer or oligomer by a polymerization of a reaction mixture of carbosilanes with amines; forming a solution containing the film forming polycarbosilazane polymer or oligomer; and contacting the solution with the substrate via a spin-on coating, spray coating, dip coating, or slit coating technique to form the silicon and carbon containing film, wherein the carbosilanes contain at least two —SiH.sub.2— moieties, either as terminal groups (—SiH.sub.2R) or embedded in a carbosilane cyclic compound, wherein R is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkyl-group, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkenyl-group, or a combination thereof, wherein the step of the producing the film forming polycarbosilazane polymer or oligomer comprises the step of adding a polysilane that contains more than two —SiH.sub.2R function groups to the reaction mixture for enhancing the polymerization of the carbosilanes with amines, wherein R is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkenyl-group, or a combination thereof.

11. The method of claim 10, further comprising the step of pre-baking the silicon and carbon containing film under N.sub.2 atmosphere at a temperature ranging from approximately 50° C. to 400° C.; and subsequently hardbaking the silicon and carbon containing film by a heat-induced radical reaction or a UV-Vis photo induced radical reaction in an atmosphere of O.sub.2, O.sub.3, H.sub.2O, H.sub.2O.sub.2, N.sub.2O, or NO, air, compressed air, or combinations thereof at a temperature range of 200-1000° C. to convert the silicon and carbon containing film to a SiOC or SiOCN containing film.

12. The method of claim 10, wherein the film forming polycarbosilazane polymer or oligomer has a backbone that comprises Si—N units, Si—N—C.sub.n—N—Si units, Si—N—Si units or combinations thereof, wherein n≥1, wherein the backbone includes cross-linked Si—N units, Si—N—C.sub.n—N—Si units or Si—N—Si units, branched Si—N units, Si—N—C.sub.n—N—Si units or Si—N—Si units, or combinations thereof.

13. The method of claim 10, wherein the carbosilane has the formula:
R.sup.1.sub.aSi[—(CH.sub.2).sub.b—SiH.sub.2R.sup.2].sub.c  (I) wherein R.sup.1, R.sup.2 are independently H, a C.sub.1 to C.sub.6 linear, branched or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched or cyclic alkenyl-group, or combination thereof; a=0 to 2; b=1 to 4; c=4-a; or
R.sup.3.sub.eC[—(CH.sub.2).sub.f—SiH.sub.2R.sup.4].sub.g  (II) wherein R.sup.3, R.sup.4 are independently H, a C.sub.1 to C.sub.6 linear, branched or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched or cyclic alkenyl-group, or combination thereof; e=0 to 2; f=0 to 3; g=4-e; or
[scaffold]-[—(CH.sub.2).sub.m—SiH.sub.2R.sup.5].sub.n  (III) wherein R.sup.5 is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched or cyclic alkenyl-group, or combination thereof; m=0 to 4; n=2 to 4; and the scaffold is a hydrocarbon scaffold; or
R.sup.6.sub.x-1,3,5-trisilacyclohexane  (IV) wherein R.sup.6 is a C.sub.1 to C.sub.6 linear, branched or cyclic alkyl- or alkenyl-group; x=0 to 3.

14. The method of claim 10, wherein the carbosilane is selected from the group consisting of Si[—(CH.sub.2)—SiH.sub.3].sub.4, Si[—(CH.sub.2).sub.2—SiH.sub.3].sub.4, Si[—(CH.sub.2).sub.3—SiH.sub.3].sub.4, Si[—(CH.sub.2).sub.4—SiH.sub.3].sub.4, R.sup.1Si[—(CH.sub.2)—SiH.sub.3].sub.3, R.sup.1Si[—(CH.sub.2).sub.2—SiH.sub.3].sub.3, R.sup.1Si[—(CH.sub.2).sub.3—SiH.sub.3].sub.3, R.sup.1Si[—(CH.sub.2).sub.4—SiH.sub.3].sub.3, H.sub.3Si—CH.sub.2—SiH.sub.2—CH.sub.2—SiH.sub.3 (bis(silylmethyl)silane), H.sub.3Si—(CH.sub.2).sub.2—SiH.sub.2—(CH.sub.2).sub.2—SiH.sub.3 (bis(2-silylethyl)silane), H.sub.3Si—(CH.sub.2).sub.3—SiH.sub.2—(CH.sub.2).sub.3—SiH.sub.3 (bis(3-silylpropyl)silane), and H.sub.3Si—(CH.sub.2).sub.4—SiH.sub.2—(CH.sub.2).sub.4—SiH.sub.3 (bis(4-silylbutyl)silane), C[—SiH.sub.3].sub.4(tetrasilylmethane), C[—(CH.sub.2)—SiH.sub.3].sub.4(2,2-bis(silylmethyl)propane-1,3-diyl)bis(silane)), C[—(CH.sub.2).sub.2—SiH.sub.3].sub.4(3,3-bis(2-silylethyl)pentane-1,5-diyl)bis(silane)), and C[—(CH.sub.2).sub.3—SiH.sub.3].sub.4(4,4-bis(3-silylpropyl)heptane-1,7-diyl)bis(silane)), R.sup.1C[—SiH.sub.3].sub.3, R.sup.1C[—(CH.sub.2)—SiH.sub.3].sub.3, R.sup.1C[—(CH.sub.2).sub.2—SiH.sub.3].sub.3, and R.sup.1C[—(CH.sub.2).sub.3—SiH.sub.3].sub.3, H.sub.3Si—CH.sub.2—SiH.sub.3 (bisilylmethane), H.sub.3Si—(CH.sub.2).sub.5—SiH.sub.3 (1,5-disilylpentane), and H.sub.3Si—(CH.sub.2).sub.7—SiH.sub.3 (1,7-disilylheptane), 1,3-disilylcyclopentane, 1,2-disilylcyclopentane, 1,4-disilylcyclohexane, 1,3-disilylcyclohexane, 1,2-disilylcyclohexane, 1,3,5-trisilylcyclohexane and 1,3,5-trisilylbenzene, 2-Me-TSCH, 2-Et-TSCH, 2-iPr-TSCH, 2-nPr-TSCH, 2-nBu-TSCH, 2-tBu-TSCH, 2-sBu-TSCH, 2-iBu-TSCH, 2,4-Me.sub.2-TSCH, 2,4-Et.sub.2-TSCH, 2,4-iPr.sub.2-TSCH, 2,4-nPr.sub.2-TSCH, 2,4-nBu.sub.2-TSCH, 2,4-iBu.sub.2-TSCH, 2,4-tBu.sub.2-TSCH, 2,4-sBu.sub.2-TSCH, 2,4,6-Me.sub.3-TSCH, 2,4,6-Et.sub.3-TSCH, 2,4,6-iPr.sub.3-TSCH, 2,4,6-nPr.sub.3-TSCH, 2,4,6-nBu.sub.3-TSCH, 2,4,6-iBu.sub.3-TSCH, 2,4,6-tBu.sub.3-TSCH, 2,4,6-sBu.sub.3-TSCH, and combinations thereof; and wherein R.sup.1 is H, a C.sub.1-C.sub.6 linear, branched, or cyclic alkyl-group, a C.sub.1-C.sub.6 linear, branched, or cyclic alkenyl-group, or a combination thereof.

15. The method of claim 10, wherein the carbosilane is 1,3,5-trisilapentane (CAS No.: 5637-99-0) or 1,3,5-trisilacyclohexane (CAS No.: 291-27-0).

16. The method of 10, wherein the step of the producing the film forming polycarbosilazane polymer or oligomer comprises the step of adding a catalyst to the reaction mixture, wherein the film forming polycarbosilazane polymer or oligomer is produced by a polymerization of the reaction mixture through a catalytic dehydrocoupling (DHC) reaction.

17. The method of claim 16, wherein the catalyst is NH.sub.4Cl.

18. The method of 10, wherein the polysilane is selected from one or more of neopentasilane (or 2,2-disilyltrisilane) (Si(SiH.sub.3).sub.4), n-tetrasilane (SiH.sub.3(SiH.sub.2).sub.2SiH.sub.3), 2-silyl-tetrasilane ((SiH.sub.3).sub.2SiHSiH.sub.2SiH.sub.3), trisilylamine (N(SiH.sub.3).sub.3), alkylamino-substituted trisilylamines or oligomers of trisilylamines.

19. The method of claim 18, wherein the film forming polycarbosilazane polymer or oligomer is produced by the polymerization of the carbosilanes with amines through the catalytic dehydrocoupling (DHC) reaction selected from one or more of i) two carbosilanes with two amines, wherein one of the two carbosilanes contains the at least two —SiH.sub.2— moieties, either as the terminal groups (—SiH.sub.2R) or embedded in the carbosilane cyclic compound; ii) two carbosilanes with two amines, wherein one of the two amines contains more than two N—H bonds; and iii) more than two carbosilanes with more than two amines, wherein R is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkenyl-group, or a combination thereof.

20. A silicon and carbon containing film forming composition comprising: a film forming polycarbosilazane polymer or oligomer that has a backbone comprising Si—N units, Si—N—C.sub.n—N—Si units, Si—N—Si or combinations thereof, wherein n≥1, wherein the backbone includes cross-linked Si—N units, Si—N—C.sub.n—N—Si units or Si—N—Si units, branched Si—N—Si units, Si—N—C.sub.n—N—Si units or Si—N—Si units, or combinations thereof wherein the film forming polycarbosilazane polymer or oligomer is obtained from a reaction mixture comprising carbosilanes and amines, wherein the carbosilanes contain at least two —SiH.sub.2— moieties, either as terminal groups (—SiH.sub.2R) or embedded in a carbosilane cyclic compound, wherein R is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkenyl-group, or combination thereof, and wherein the reaction mixture further comprises a polysilane that contains more than two —SiH.sub.2R function groups, wherein R is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alky- group, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkenyl-group, or a combination thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The foregoing and various other aspects, features, and advantages of the present invention, as well as the invention itself, may be more fully appreciated with reference to the following detailed description of the invention when considered in connection with the following drawings. The drawings are presented for the purpose of illustration only and are not intended to be limiting of the invention, in which:

(2) FIG. 1 is a simplified flow chart for a SOD process;

(3) FIG. 2 is a thermogravimetric analysis (TGA) graph of the TSCH-based polycarbosilazane solution;

(4) FIG. 3 is a FTIR spectrum comparison of pre-bake of a SOD film at 200° C. under N.sub.2 and hardbake of the prebaked SOD film at 350° C. in air for about 30 min;

(5) FIG. 4 is the low frequency region (1,500-650 cm.sup.−1) FTIR spectrum of FIG. 3;

(6) FIG. 5 is the high frequency region (4,000-1,500 cm.sup.−1) FTIR spectrum of FIG. 3, and

(7) FIG. 6 is a FTIR spectrum comparison of the prebaked SOD film and the hardbaked SOD film.

DESCRIPTION OF PREFERRED EMBODIMENTS

(8) Disclosed are silicon and carbon containing film forming compositions comprising a polycarbosilazane containing formulation for deposition of Si-containing low-k dielectric film, methods of synthesizing the polycarbosilazanes and methods of using the silicon and carbon containing film forming compositions to deposit silicon and carbon containing films for manufacturing SiOC, SiOCN or SiCN devices. Particularly, the disclosed methods are spin-on deposition (SOD) of the silicon and carbon containing film forming composition comprising the polycarbosilazane containing formulation followed by pre-baking (or curing) and hardbaking processes to form a low-k dielectric film, such as a SiOC or SiOCN film.

(9) The disclosed silicon and carbon containing film forming compositions have properties suitable for spin-on coating, spray coating, dip coating, or slit coating methods, such as low melting point (preferably being in liquid form at room temperature), and good wetting behavior on the substrate to be coated, and good thermal stability for shelf life and storage without degradation. Oligomers and/or polymers of the disclosed polycarbosilazanes suitable for these deposition techniques typically have a molecular weight ranging from approximately 300 Da to approximately 1,000,000 Da, preferably from approximately 500 Da to approximately 100,000 Da, and more preferably from approximately 1,000 Da to approximately 50,000 Da.

(10) The oligomers and/or polymers of the disclosed polycarbosilazanes may be produced by catalytic dehydrogenative coupling (DHC) reactions of carbosilane monomers and amine monomers. The preferred carbosilanes used for syntheses of the disclosed polycarbosilazanes contain at least two —SiH.sub.2R groups (R is H, a C.sub.1-C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1-C.sub.6 linear, branched, or cyclic alkenyl- group, or combination thereof; the —SiH.sub.2R may be part of a cyclic structure containing C and Si) to facilitate the reaction of the carbosilane with the amine in the DHC process to form polycarbosilazane. The amine used for the DHC reaction with the carbosilane may be selected from one or several of ammonia, amidine, hydrazine, hydroxylamine, monoalkylamine, diamines or polyamines or the like, so long as they contain at least two N—H bonds. Such N—H bonds may be on the same nitrogen atom, i.e. for a primary amine —NH.sub.2, or on separate N atoms, for instance in a dialkyldiamine (RNH—C.sub.2H.sub.4—NHR). However, branched or cross-linked polycarbosilazanes may be formed if the amine or carbosilane contains at least 3 N—H bonds or at least 3 —SiH.sub.2R groups for branched and/or crosslinked polymerization. If either the amine or the carbosilane contain at least 3 N—H bonds or at least 3 —SiH.sub.2R groups, respectively, polycarbosilazanes may be obtained with extended crosslinks. The extent of crosslinks may be moderated by using mixed carbosilane monomers. For example, one may use a mixture of carbosilanes, one that contains at least 3 —SiH.sub.2R groups and the other one containing only 2 —SiH.sub.2R groups. Alternatively, the extent of crosslinks may be moderated by using mixed amine monomers. For example, one may use a mixture of amines, one that contains at least 3 N—H bonds and the other one containing only 2 N—H bonds. The percentage of any one of the carbosilanes or amines may range from 0.5% to 99.5% in molar percentage depending on a desired extent of crosslinks. Preferably, the ratio of amine to carbosilane monomers is selected so that the number of —NH functions in the DHC reaction stoichiometry is higher than the number of —SiH.sub.2R functions.

(11) The carbosilane monomers used for synthesizing the disclosed polycarbosilazanes may contain —Si—C.sub.n—Si— unit (n≥1) unit that may be a linear, branched or cyclic saturated or unsaturated structure. In addition, the carbosilane monomers used for synthesizing the disclosed polycarbosilazanes may contain a 1,3,5-trisilacyclohexane (TSCH) backbone. The cyclic structure of the carbosilane monomer is preferred for low-k films as it creates a molecular scale porosity in the final film, this decreases the film density and dielectric constant. 1,3,5-trisilacyclohexane is found to be particularly interesting for this application.

(12) The carbosilane monomers used for synthesizing the disclosed polycarbosilazanes have the following formulae:
R.sup.1.sub.aSi[—(CH.sub.2).sub.b—SiH.sub.2R.sup.2].sub.c  (I)
wherein R.sup.1, R.sup.2 are independently H, a C.sub.1-C.sub.6 linear, branched or cyclic alkyl- group or alkenyl- group, or combination thereof; a=0-2; b=1-4; c=4-a; or
R.sup.3.sub.eC[—(CH.sub.2).sub.f—SiH.sub.2R.sup.4].sub.g  (II)
wherein R.sup.3, R.sup.4 are independently H, a C.sub.1-C.sub.6 linear, branched or cyclic alkyl- group or alkenyl- group, or combination thereof; e=0-2; f=0-3; g=4-e; or
[scaffod]-[—(CH.sub.2).sub.m—SiH.sub.2R.sup.5].sub.n  (III)
wherein R.sup.5 is H, a C.sub.1-C.sub.6 linear, branched, or cyclic alkyl- group or alkenyl- group, or combination thereof; m=0-4; n=2-4; and the scaffold is a hydrocarbon scaffold; or
R.sup.6.sub.x-1,3,5-trisilacyclohexane  (IV)
wherein R.sup.6 is a C.sub.1-C.sub.6 linear, branched or cyclic alkyl- or alkenyl- group; x=0-3.

(13) Formula III may also be expressed in a structure below.

(14) ##STR00002##
wherein

(15) ##STR00003##
is a hydrocarbon scaffold. The examplary hydrocarbon scaffold includes, but is not limited to, a C.sub.3-C.sub.10 cyclic hydrocarbon scaffold. The hydrocarbon scaffold may contain silyl- group, —NH group, —O— ether group, or the like.

(16) The carbosilane monomers shown in Formula I may contain at least two —SiH.sub.2R.sup.2 or —SiH.sub.3 groups and hydrocarbon chains. For example, when a=0, b=1-4, c=4, and R.sup.2=H, the carbosilane monomers include Si[—(CH.sub.2)—SiH.sub.3].sub.4 (tetrakis(silylmethyl)silane), Si[—(CH.sub.2).sub.2—SiH.sub.3].sub.4 (tetrakis(2-silylethyl)silane), Si[—(CH.sub.2).sub.3—SiH.sub.3].sub.4 (tetrakis(3-silylpropyl)silane), and Si[—(CH.sub.2).sub.4—SiH.sub.3].sub.4 (tetrakis(4-silylbutyl)silane), having a general structure:

(17) ##STR00004##
When a=1, b=1-4, c=3; R.sup.1 is H, a C.sub.1-C.sub.6 linear, branched, or cyclic alkyl- group or a C.sub.1-C.sub.6 linear, branched, or cyclic alkenyl- group; and R.sup.2=H, the carbosilane monomers include R.sup.1Si[—(CH.sub.2)—SiH.sub.3].sub.3, R.sup.1Si[—(CH.sub.2).sub.2—SiH.sub.3].sub.3, R.sup.1Si[—(CH.sub.2).sub.3—SiH.sub.3].sub.3, and R.sup.1Si[—(CH.sub.2).sub.4—SiH.sub.3].sub.3, having a general structure:

(18) ##STR00005##
When a=2, b=1-4, c=2; R.sup.1=H; and R.sup.2=H, the carbosilane monomers include H.sub.3Si—CH.sub.2—SiH.sub.2—CH.sub.2—SiH.sub.3 (1,3,5-trisilapentane (TSP) or bis(silylmethyl)silane) (CAS No. 5637-99-0), H.sub.3Si—(CH.sub.2).sub.2—SiH.sub.2—(CH.sub.2).sub.2—SiH.sub.3 (bis(2-silylethyl)silane), H.sub.3Si—(CH.sub.2).sub.3—SiH.sub.2—(CH.sub.2).sub.3—SiH.sub.3 (bis(3-silylpropyl)silane), and H.sub.3Si—(CH.sub.2).sub.4—SiH.sub.2—(CH.sub.2).sub.4—SiH.sub.3 (bis(4-silylbutyl)silane). Here are the structures.

(19) ##STR00006##

(20) The carbosilane monomers shown in Formula II may contain at least two —SiH.sub.3 groups and hydrocarbon chains. For example, when a=0, b=0-3, c=4; and R.sup.2=H; the carbosilane monomers include C[—SiH.sub.3].sub.4 (tetrasilylmethane), C[—(CH.sub.2)—SiH.sub.3].sub.4 ((2,2-bis(silylmethyl)propane-1,3-diyl)bis(silane)), C[—(CH.sub.2).sub.2—SiH.sub.3].sub.4((3,3-bis(2-silylethyl)pentane-1,5-diyl)bis(silane)), and C[—(CH.sub.2)—SiH.sub.3].sub.4((4,4-bis(3-silylpropyl)heptane-1,7-diyl)bis(silane)), having a general structure:

(21) ##STR00007##
When a=1, b=0-3, c=3; and R.sup.1 is H, a C.sub.1-C.sub.6 linear, branched, or cyclic alkyl- group or a C.sub.1-C.sub.6 linear, branched, or cyclic alkenyl- group, the carbosilane monomers include R.sup.1C[—SiH.sub.3].sub.3, R.sup.1C[—(CH.sub.2)—SiH.sub.3].sub.3, R.sup.1C[—(CH.sub.2).sub.2—SiH.sub.3].sub.3, and R.sup.1C[—(CH.sub.2).sub.3—SiH.sub.3].sub.3, having a general structure:

(22) ##STR00008##
When a=2, b=0-3, c=2; R.sup.1=H; and R.sup.2=H; the carbosilane monomers include H.sub.3Si—CH.sub.2—SiH.sub.3 (bisilylmethane), H.sub.3Si—(CH.sub.2).sub.3—SiH.sub.3 (1,3-disilylpropane), H.sub.3Si—(CH.sub.2).sub.5—SiH.sub.3 (1,5-disilylpentane), and H.sub.3Si—(CH.sub.2).sub.7—SiH.sub.3(1,7-disilylheptane).

(23) In formula III, multiple carbosilane groups may be attached to a hydrocarbon scaffold such as cyclic rings and may form N—H bonds for polycarbosilazane formation. The carbosilane monomers shown in formula III may contain hydrocarbon scaffolds connected with two —SiH.sub.2R groups or carbosilyl groups. For example, when c=2 in formula III, the carbosilane monomers include:

(24) ##STR00009##
wherein

(25) ##STR00010##
is a hydrocarbon scaffold, such as a C.sub.3 to C.sub.10 cyclic hydrocarbon scaffold that may contain silyl- group, —NH group, —O— ether group, or the like.
When R.sup.5=H, the carbosilane monomers include

(26) ##STR00011##
wherein

(27) ##STR00012##
is a hydrocarbon scaffold, such as a C.sub.3 to C.sub.10 cyclic hydrocarbon scaffold that may contain silyl- group, —NH group, —O— ether group, or the like.

(28) The exemplary carbosilanes include:

(29) ##STR00013##

(30) The carbosilane monomers shown in Formula III may contain at least two —SiH.sub.2R groups, hydrocarbon chains and hydrocarbon scaffolds. For example, when c=3, the carbosilane monomers include:

(31) ##STR00014##
wherein

(32) ##STR00015##
is a hydrocarbon scaffold, such as a C.sub.3 to C.sub.10 cyclic hydrocarbon scaffold that may contain silyl- group, —NH group, —O— ether group, or the like.

(33) The carbosilane monomers in formula III may contain hydrocarbon scaffold connected with three —SiH.sub.3 groups or carbosilyl groups. For example, when c=3; R.sup.5=H, the carbosilane monomers include:

(34) ##STR00016##
wherein

(35) ##STR00017##
is a hydrocarbon scaffold, such as a C.sub.3 to C.sub.10 cyclic hydrocarbon scaffold that may contain silyl- group, —NH group, —O— ether group, or the like. The exemplary carbosilanes include 1,3,5-trisilylcyclohexane and 1,3,5-trisilylbenzene:

(36) ##STR00018##

(37) The carbosilane monomers shown in formula III may contain at least four —SiH.sub.2R.sup.5 groups and hydrocarbon chains and hydrocarbon scaffolds. That is, the carbosilane monomers may contain a hydrocarbon scaffold connected with four —SiH.sub.2R.sup.5 groups or carbosilyl groups. For example, when c=4, the carbosilane monomers include:

(38) ##STR00019##
wherein

(39) ##STR00020##
is a hydrocarbon scaffold, such as a C.sub.3 to C.sub.10 cyclic hydrocarbon scaffold that may contain silyl- group, —NH group, —O— ether group, or the like.

(40) The carbosilane monomers shown in formula IV may contain one 1,3,5-trisilacyclohexane (TSCH) group, which forms a molecular size void in the carbosilane molecule and hydrocarbon chains. When x=0, R.sup.6 is H, the carbosilane is TSCH (CAS No.: 291-27-0),

(41) ##STR00021##
When x=1, R.sup.6 is at C.sub.2 position. The carbosilanes are 2-R.sup.6-1,3,5-trsilacyclohexane (2-R.sup.6-TSCH). Exemplary of the carbosilanes include 2-Me-TSCH, 2-Et-TSCH, 2-iPr-TSCH, 2-nPr-TSCH, 2-nBu-TSCH, 2-tBu-TSCH, 2-sBu-TSCH, 2-iBu-TSCH, etc. When x=2, two R.sup.6 are at C.sub.2 and C.sub.4 positions, 2,4-R.sup.6.sub.2-1,3,5-trisilacyclohexane (2,4-R.sup.6.sub.2-TSCH). Exemplary of the carbosilanes include 2,4-Me.sub.2-TSCH, 2,4-Et.sub.2-TSCH, 2,4-iPr.sub.2-TSCH, 2,4-nPr.sub.2-TSCH, 2,4-nBu.sub.2-TSCH, 2,4-iBu.sub.2-TSCH, 2,4-tBu.sub.2-TSCH, 2,4-sBu.sub.2-TSCH. When x=3, three R.sup.6 are at C.sub.2, C.sub.4 and C.sub.6 positions, 2,4,6-R.sup.6.sub.3-1,3,5-trsilacyclohexane (2,4,6-R.sup.6.sub.3-TSCH). Exemplary of the carbosilanes include 2,4,6-Me.sub.3-TSCH, 2,4,6-Et.sub.3-TSCH, 2,4,6-iPr.sub.3-TSCH, 2,4,6-nPr.sub.3-TSCH, 2,4,6-nBu.sub.3-TSCH, 2,4,6-iBu.sub.3-TSCH, 2,4,6-tBu.sub.3-TSCH, and 2,4,6-sBu.sub.3-TSCH.

(42) The disclosed polycarbosilazanes may be synthesized by a catalytic DHC reaction of a carbosilane shown in Formulae I, II, III and IV and liquid ammonia under pressure. The carbosilane shown in Formulae I, II, III and IV may be written as R.sub.xSi.sub.yH.sub.z in a general formula, where x, y and z≥1. Then the reaction scheme is as follows:
R.sub.xSi.sub.yH.sub.z+NH.sub.3=R.sub.xSi.sub.yH.sub.(z-1)NH.sub.2+H.sub.2  (1)
2R.sub.xSi.sub.yH.sub.(z-1)NH.sub.2═[R.sub.xSi.sub.yH.sub.(z-1)]NH+NH.sub.3  (2)

(43) wherein x, y and z≥1; R is H, a C.sub.1 to C.sub.6 linear, branched, a cyclic alkyl-group or a C.sub.1 to C.sub.6 linear, branched, or cyclic alkenyl- group, or combination thereof. In one embodiment, R contains Si atoms with active H participating in the similar reactions. Alternatively, R may contain the following units: —SiH.sub.a—C—SiH.sub.b— and/or —SiH.sub.a—C—C—SiH.sub.b— and/or —SiH.sub.a—C—C—C—SiH.sub.b— and/or —SiH.sub.a—C—C—C—C—SiH.sub.b—, where a and b are integers from 0 to 3 (if a and/or b=3, the corresponding Si atom is terminal). Alternatively, R may contain TSCH group. Reaction (1) may not necessarily be followed by reaction (2). In this case, an oligomer having some terminal —NH.sub.2 groups is obtained. Reaction (1) usually requires a catalyst. That is, Reaction (1) is a catalytic dehydrogenative coupling (DHC) of carbosilane(s) and amine(s). The catalytic DHC is a preferred synthesis pathway for polycarbosilazane syntheses because the reaction byproduct is hydrogen, which is vented out easily. The catalyst may be heterogeneous or homogeneous. Examples of the heterogeneous catalysts are Pt and Pt-group metals (supported or unsupported). Examples of the homogeneous catalysts include substituted or unsubstituted ammonium and phosphonium salts, metal amides, other Lewis and Bronstedt acids and bases soluble in the reaction media. For example, a homogeneous NH.sub.4Cl is used in the Examples that follow. The process may be conducted in a batch mode or in a flow-through mode.

(44) Theoretically, the entire process can be conducted with both reagents in gas phase, both reagents in liquid phase or with one of the starting materials in the liquid and the other in a gas phase. The reactions may proceed in presence of a solvent or without a solvent. The suitable solvents are hydrocarbons (e.g., hexane, heptane, etc.), aromatics (e.g., benzene, toluene, xylene, etc.), halogenated hydrocarbons (e.g., methylene chloride, chloroform, dichloroethane, chlorobenzene, etc.), ethers, amines and their mixtures. If ammonia is supposed to be in a vapor phase only, the reactions may be conducted at temperatures up to a stability limit of the chosen carbosilane.

(45) The reaction temperature range could be from approximately 20° C. to approximately 300° C., preferably from approximately 100° C. to approximately 200° C. If ammonia acts a solvent or co-solvent, the reactions have to be conducted at temperature and pressure conditions where NH.sub.3 exists as a liquid. The preferred temperature range is approximately 20° C. to approximately 100° C. under pressure. The preferred pressure range is about from 100 to 1500 psig.

(46) The disclosed synthesis methods may be scaled up to produce a large amount of the product. For example, scaled up to approximately 1 kg to approximately 100 kg.

(47) In order to make polymer chains of the disclosed polycarbosilazanes, the amines used herein each have to contain two or more N—H bonds that react with Si—H bonds in the carbosilane to form the polymer chains of the polycarbosilazanes. Two N—H bonds are the minimum requirement for polymer formation, and additional N—H bond needs to form silazane-bridged or crosslinked and/or branched polymers. The at least two N—H bonds may be attached to the same nitrogen atom or to the different nitrogen atoms in one amine. Specifically, the amines used herein are selected from ammonia, amidine, hydrazine, hydroxylamine, or C.sub.1 to C.sub.6 monoalkylamine, diamines including ethylene diamine, or polyamines, which contain at least two N—H bonds for polymer formation with the carbosilanes.

(48) As described above, in order to enhance the silazane-bridges or crosslinks of the disclosed polycarbosilazanes, the carbosilane monomers should have at least two —SiH.sub.2R groups (R is H, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1 to C.sub.6 linear, branched, or cyclic alkenyl- group, or combination thereof) to react with N—H bond of the amine to form branched and/or crosslinked polycarbosilazane polymers, which improves certain physical properties of the resulting Si-containing film including etching properties. For example, the carbosilanes shown in Formula I have more than two —SiH.sub.2R.sup.2 groups and may participate in the catalytic DHC reaction with the amine to form polycarbosilazanes. Specially, the carbosilane monomers in Formula I may contain up to four carbosilyl groups attached to the Si atom. Thus, the minimum number of the carbosilyl group is two, which will produce three —SiH.sub.2R.sup.2 groups for crosslinked and branched polycarbosilazanes or oligomer polycarbosilazanes. In Formula I, the carbosilane monomer contains both carbon atoms adjustable based on the length of carbon chain as well as attached alkyl group R.sup.2. Both R.sup.1 and R.sup.2 have additional functional groups such as olefinic group for crosslinking. Additionally, the carbosilyl groups attached to Si are not necessarily to be the same and they may be different in carbon chain length as well as with different function groups of R.sup.2. However, for manufacturing, chemicals with the same functional groups will be easier to synthesize. The alkenyl group may be used as a function group for radical reaction for crosslink or polymerization with other alkenyl groups in the polycarbosilazane in the curing and hardbaking steps. The number of R.sup.1 may be from 0 to 2. When number of R.sup.1 is zero, the monomer is tetra-substituted.

(49) As described above, in order to synthesize polycarbosilazanes from carbosilane(s) and amine(s) through Si—N bond formation by a catalytic DHC process, the carbosilane needs to have at least two Si—H bonds and the amine needs to have at least at least two N—H bonds as showed in Equation II below.

(50) ##STR00022##

(51) Branched or crosslinked (or silazane-bridged) polycarbosilazanes through Si—N bond formation require that one of the carbosilane monomers or one of the amines has to have three functional groups, either three or more —SiH.sub.2R.sup.2 groups (or Si—H bonds) in the carbosilane or three or more N—H bonds in the amine to participate in a chain growth, crosslinking and branching. An example of the crosslinked polycarbosilazanes is shown in Equation III below. The carbosilanes may be a mixture of a two Si—H bond containing carbosilane and a three Si—H bond containing carbosilane. Extent of the crosslinks may be moderated by adjusting a mixture ratio of the carbosilane having two Si—H groups and the carbosilane having three or more Si—H groups while the amine remains two N—H bonds. Similarly, the amines may be a mixture of a two N—H bond containing amine and a three N—H bond containing amine. The percentage of one carbosilane monomer in the mixture of the two carbosilanes may range from 0.5% to 99.5% in molar percentage depending on desired crosslinks. Similarly, a mixture of a two N—H bond containing amine and a three N—H bond containing amine may be applied to the catalytic DHC reaction with carbosilanes. The percentage of one amine in the mixture of the two amines may range from 0.5% to 99.5% in molar percentage depending on desired crosslinks. The amines used herein include ammonia, alkylamine, alkenyl amine, hydrazine, amidine, and the like. A polysilanes and polyhalosilane may be used as a crosslink additive or reagent to react with N—H bonds to enhance the crosslinked and branched polymerization. Alternatively, additional crosslinks may be formed by using the carbosilane, or amine having unsaturated carbon-carbon bonds (i.e., C═C and/or C≡C) and additional Si—H bond generated through radical reactions (e.g., curing and hard baking steps) following the SOD. The radical reaction may be induced by UV-Vis light or heat in the hardbaking process described below.

(52) ##STR00023##

(53) The disclosed also include processes of making polycarbosilazane having crosslinks with a mixture of carbosilanes and/or with a mixture of amines. The disclosed polycarbosilazanes may be synthesized with a mixture of carbosilanes and a mixture of amines. A mixture of two carbosilanes contains one carbosilane having three or four —SiH.sub.2R.sup.2 groups and the other carbosilane having two —SiH.sub.2R.sup.2 groups. The carbosilane having three or four —SiH.sub.2R.sup.2 will be the crosslink sites. Similarly, a mixture of two amines contains one amine having three or more N—H bonds and the other amines containing two N—H bonds. Again, the percentage of any one of the carbosilanes or amines in the mixture may range from 0.5% to 99.5% in molar percentage.

(54) The mixture of carbosilanes and amines may include one carbosilane and one amine for forming the polycarbosilazane. Alternatively, the mixture of carbosilanes and amines may include more than one carbosilanes or more than one amines for forming the branched and/or crosslinked polycarbosilazanes.

(55) In one embodiment, the process of forming the polycarbosilazanes may be performed with two carbosilanes, in which one carbosilane contains more —SiH.sub.2R functional groups than the other for enhancing a crosslink polymerization reaction with amines.

(56) In yet another alternative, the process of forming the polycarbosilazanes may be performed with two amines, in which one amine contains more N—H bonds than the other for enhancing a crosslink polymerization reaction with carbosilanes.

(57) In yet another alternative, the process of forming the polycarbosilazanes may be performed with more than two carbosilanes with at least one amine.

(58) In yet another alternative, the process of making the polycarbosilazanes may be performed with more than two amines with at least one carbosilane.

(59) In yet another alternative, the process of making the polycarbosilazanes may be performed with a combination of multiple carbosilanes and multiple amines.

(60) The disclosed silicon and carbon containing film forming compositions may contain other monomers, such as polysilanes. The polysilanes contain no carbon chain and have at least three —SiH.sub.2R groups favorable of forming branched and/or crosslinked polymers along with the polycarbosilazanes. Exemplary polysilanes include neopentasilane (Si(SiH.sub.3).sub.4), n-tetrasilane (SiH.sub.3(SiH.sub.2).sub.2SiH.sub.3), 2-silyl-tetrasilane ((SiH.sub.3).sub.2SihSiH.sub.2SiH.sub.3), trisilylamine (N(SiH.sub.3).sub.3) or trisilyamine derivatives such as alkylamino-substituted trisilylamines or oligomers of trisilylamines, including but not limited to:

(61) ##STR00024##

(62) The disclosed polycarbosilazane containing formulation are suitable for being used in a coating formulation, preferably a spin-on coating or SOD applications due to at least partially to the benefits discussed above for Si—H bonds. The amino ligand may also provide improved thermal stability, as well as an additional N and/or C source for the thermal stability of the resulting film.

(63) The disclosed silicon and carbon containing film forming composition typically contains 1-20% by weight of the non-volatile polycarbosilazane oligomer/polymer in a solvent or solvent mixture, preferably 2% to 10%. The solvent or solvent mixture is selected from at least one of hydrocarbons, aromatic solvents such as toluene, xylene or mesitylene, ethers such a tert-butyl ethers, THF or glymes, amines such as trialkylamine or dialkylamine, etc. The disclosed silicon and carbon containing film forming compositions may include other components to improve the overall resulting film properties, improve the wettability to the surface, tune the final film composition, and reduce the shrinkage of the film during the curing and baking steps. As such, the disclosed silicon and carbon containing film forming compositions may contain catalysts, surfactants, wetting agents, and other polymers, oligomers or monomers such as, but is not limited to, polysilazane, polycarbosilanes, polysilanes, metal or metailloid organometallic monomers or oligomers.

(64) Also disclosed are methods of using the disclosed silicon and carbon containing film forming compositions in coating deposition methods, such as spin-on coating, spray coating, dip coating or slit coating techniques. To be suitable for coating methods, the disclosed polycarbosilazanes should have a molecular weight ranging from approximately 300 Da to approximately 1,000,000 Da, preferably from approximately 500 Da to approximately 100,000 Da, and more preferably from approximately 1,000 Da to approximately 50,000 Da.

(65) The disclosed methods provide for the use of the silicon and carbon containing film forming compositions for deposition of silicon-containing films, specifically silicon-carbon-containing films. The disclosed methods may be useful in the manufacture of semiconductor, photovoltaic, LCD-TFT, optical coatings, or flat panel type devices. The method include: a) applying a liquid form of the disclosed silicon and carbon containing film forming compositions comprising the polycarbosilazane containing formulations on a substrate, b) curing to remove the solvent or solvents and form a polycarbosilazane film on at least parts of the substrate, and c) hardbaking the polycarbosilazane film in an oxidative atmosphere to convert at least some of the Si—NR—Si (silazane) bridges between the carbosilane monomers to Si—O—Si (siloxane) bridges, under conditions where at least part of the carbosilane backbone structure remains.

(66) Prior to spin coating, the substrate may be exposed to a treatment and surface modification aiming at improving the wettability of the silicon and carbon containing film forming composition on the substrate. This treatment may be a mere solvent exposure, or a chemical treatment aiming at modifying the chemical surface composition. The surface modification may be carried in the gas phase or by exposing the substrate to a solution containing the surface modifying agent. The surface modifying agent may contain chemical functions that will chemically react during the curing or the baking step to improve the adhesion of the film to the substrate. Example of such chemical modification agents have the formula X.sub.xSiR.sub.4-x, or SiR.sub.3—NH—SiR.sub.3 in which X is a chemical group reactive with surface hydroxyl groups such as halide, alkylamino, acetamide, etc., and R is independently selected from H, a C.sub.1 to C.sub.20 alkyl, alkenyl, or alkyne group, and x=1,2,3. For instance, the surface modification chemical may be Me.sub.3Si—NMe.sub.2. The surface modifying group may preferentially react with certain area of the substrate and create a preferential adhesion of the polycarbosilazane on certain areas, leading to at least partially selective deposition of the polycarbosilazane.

(67) SOD generally consists of three steps: spin-on coating, soft baking (or curing), and hard baking. A liquid form or solution of the disclosed polycarbosilazane containing formulation may be applied directly to the center of a substrate. The solution is then evenly distributed to the entire substrate during a spinning process forming a film on the substrate. A film thickness may be controlled by adjusting a concentration of the disclosed polycarbosilazane containing formulation, the solvent or solvent mixture choice, and the spin rate or rates if the spin recipe has several steps. The as-deposited film may be then baked on a hot plate or other heating equipment for a period of time to vaporize the solvent(s) or volatile components of the film. The soft bake temperature may be varied from 50 to 400° C., depending on the property of the solvent. The soft bake may be carried in an inert atmosphere to the polycarbosilazane film, or to an atmosphere that contains O.sub.2 and/or H.sub.2O, leading to a pre-reaction of the polycarbosilazane film. Eventually, the hard bake process may be carried out by annealing the substrate in an oxidizing atmosphere, such as O.sub.2, O.sub.3, H.sub.2O, H.sub.2O.sub.2, N.sub.2O, NO, air, compressed air and combination thereof, at a temperature ranging from 200 to 1000° C. The film quality may be improved by optimizing a ramping rate, temperature, annealing duration, and oxidizer combinations, etc. The extent of the conversion of the silazane bridges to siloxane bridges can be controlled by the annealing temperature, the composition of the annealing atmosphere, and by the annealing time.

(68) Exemplary coating deposition methods include spin-on coating or spin-on deposition (SOD). FIG. 1 provides a flow chart of an exemplary SOD process following the formation and formulation of polycarbosilazanes for SOD. One of ordinary skill in the art will recognize that fewer or additional steps than those provided in FIG. 1 may be performed without departing from the teachings herein. One of ordinary skill in the art will further recognize that the process is preferably performed under an inert atmosphere to prevent undesired oxidation of the film and/or in a clean room to help prevent contamination to prevent particle contamination of the film. In Step A, as described above, the polycarbosilazanes are synthesized by a catalytic DHC reaction of the disclosed carbosilanes shown in Formula I, II, III and IV and amines. Step B is the formulation of the synthesized polycarbosilazanes for SOD process. The synthesized polycarbosilazanes may then be separated and filtered to remove reactants, catalysts, solid by-products, undesired long-chain solid polymers or the like. Thereafter, the polycarbosilazane containing formulation is prepared for the SOD, which may contain 1-20% polycarbosilazane in a solvent. One of ordinary skill in the art will recognize that the required duration of the SOD process, the spin acceleration rate of the substrate, the solvent evaporation rate, etc., are adjustable parameters that require optimization for each new formulation in order to obtain the target film thickness and uniformity (see, e.g., University of Louisville, Micro/Nano Technology Center-Spin Coating Theory, October 2013). In addition, depending on the target Si-containing film, the silicon and carbon containing film forming composition may include additional reagents, such as, additives and/or surfactants, etc. for enhancing the polymerization and the connectivity or crosslink of the SOD film through a hardbaking process. For instance, the silicon and carbon containing film forming composition may include a polysilane that contains more than two —SiH.sub.2R function groups, wherein R is H, a C.sub.1-C.sub.6 linear, branched, or cyclic alkyl- group, a C.sub.1-C.sub.6 linear, branched, or cyclic alkenyl- group, or combination thereof, to enhance a crosslinked and branched polymerization of the target film.

(69) Next, a planar or patterned substrate on which the Si-containing film is to be deposited may be cleaned or prepared for the deposition process in Step 1. High purity gases and solvents are used in the preparation process. Gases are typically of semiconductor grade and free of particle contamination. For semiconductor usage, solvents should be particle free, typically less than 100 particle/mL (0.5 μm particle, more preferably less than 10 particles/mL) and free of non-volatile residues that would lead to surface contamination. Semiconductor grade solvents having less than 50 ppb metal contamination (for each element, and preferably less than 5 ppb) are advised.

(70) In Step 1, the substrates (planar or patterned substrates) or wafers is cleaned using typical chemical cleaning agents in the art, such as, isopropanol (IPA), acetone or the like. The cleaning step is mainly to remove any contaminations on the substrates surface. One of ordinary skill in the art may determine the appropriate wafer preparation process based at least upon the substrate material and degree of cleanliness required. After the substrate cleaning preparation, the clean substrate is then transferred into a spin coater at Step 2. A liquid form or solution of the polycarbosilazane containing formulation is dispensed onto the substrate. The spin rates may be adjusted typically from 1000 rpm to 10000 rpm. The substrate is spun until a uniform Si-containing film formed on the entire surface of the substrate. The spinning time may vary from 10 s to 3 min. One of ordinary skill in the art will recognize that this spin-on deposition process may be conducted either in a static mode (sequentially) or a dynamic mode (concurrently). This spin-on deposition is preferred to be conducted in a controlled gas environment. For example, in a controlled O.sub.2 level or H.sub.2O level. One of ordinary skill in the art will recognize that a required duration of the spin coating process, the acceleration rate, the solvent evaporation rate, etc., are adjustable parameters that require optimization for each new formulation of the polycarbosilazane containing formulation in order to obtain a target film thickness and uniformity (see, e.g., University of Louisville, Micro/Nano Technology Center-Spin Coating Theory, October 2013).

(71) After the Si-containing film is formed on the substrate, the substrate is pre-baked or soft baked at Step 3 to remove any remaining volatile organic components of the polycarbosilazane containing formulation and/or by-products from the spin-coating process. The pre-bake may take place in a thermal chamber or on a hot plate at a temperature ranging from approximately 50° C. to approximately 400° C. for a time period ranging from approximately 1 minute to approximately 30 minutes. After pre-bake, the Si-containing film on the substrate is then cured to a desired dielectric film, such as a SiOC film, through a hard bake process (Step 4).

(72) The hard bake process may be carried out by a heat-induced radical reaction for polymerization of olefinic groups in the silicon-containing film (i.e., the polycarbosilazane film) through thermal annealing in an oxidizing atmosphere at a temperature ranging from approximately 200° C. to approximately 1000° C. for a period ranging from approximately 30 minutes to approximately 4 hours. The oxidizers may be selected from O.sub.2, O.sub.3, H.sub.2O, H.sub.2O.sub.2, N.sub.2O, NO, air, compressed air and combination thereof. Alternatively, the Si-containing film may be cured through UV-curing, that is, a UV-Vis photo induced radical reaction for polymerization of olefinic groups in the silicon-containing film (i.e., the polycarbosilazane film). The Si-containing film is subjected to UV-curing at the wavelength ranges from 190 to 400 nm using a monochromatic or polychromatic source. In another alternative, both the thermal and UV process may be performed at the same temperature and wavelength criteria specified for Step 4. One of ordinary skill in the art will recognize that the choice of curing methods and conditions will be determined by the target silicon-containing film desired.

(73) In Step 5, the cured film is characterized using standard analytic tools. Exemplary tools include, but are not limited to, ellipsometers, x-ray photoelectron spectroscopy, atomic force microscopy, x-ray fluorescence, fourier-transform infrared spectroscopy, scanning electron microscopy, secondary ion mass spectrometry (SIMS), Rutherford backscattering spectrometry (RBS), profilometer for stress analysis, or combination thereof.

(74) Briefly, the liquid form of the disclosed silicon and carbon containing film forming composition may be applied directly to the center of the substrate and then spread to the entire substrate by spinning or may be applied to the entire substrate by spraying. When applied directly to the center of the substrate, the substrate may be spun to utilize centrifugal forces to evenly distribute the composition over the substrate. Alternatively, the substrate may be dipped in the silicon and carbon containing film forming composition. The resulting film may be dried at room temperature for a period of time to vaporize the solvent or volatile components of the film or dried by force-drying or baking or by the use of one or a combination of any following suitable process including thermal curing and irradiations, such as, ion irritation, electron irradiation, UV and/or visible light irradiation, etc.

(75) The disclosed silicon and carbon containing film forming compositions comprising the polycarbosilazane containing formulation may be used to form spin-on dielectric film formulations, for lithographic applications such as tone inversion or for anti-reflective films. For example, the disclosed silicon and carbon containing film forming compositions may be included in a solvent or solvent mixture and applied to a substrate to form a polycarbosilazane film. If necessary, the substrate may be rotated to evenly distribute the silicon and carbon containing film forming composition across the substrate. One of ordinary skill in the art will recognize that the viscosity of the silicon and carbon containing film forming compositions will contribute as to whether rotation of the substrate is necessary. The resulting polycarbosilazane film may be heated under an inert gas, such as argon, helium, or nitrogen and/or under reduced pressure. Alternatively, the resulting polycarbosilazane film may be heated under a reactive gas like NH.sub.3 or hydrazine to enhance the connectivity and nitridation of the film. Electron beams or ultraviolet radiation may be applied to the resulting polycarbosilazane film. The reactive groups of the disclosed polycarbosilazanes (i.e., the direct Si—N, N—H or Si—H bonds) may prove useful to increase the connectivity of the polymer obtained. Alternatively, the resulting polycarbosilazane film may be heated under a reactive gas like O.sub.3 to enhance the connectivity and oxidization of the resulting polycarbosilazane film so that nitrogen in the resulting polycarbosilazane film is converted to oxygen. Thus, nitrogen in the resulting polycarbosilazane film may be completely or at least partially replaced with oxygen to form a target SiOC or SiOCN film after a hard bake.

(76) The silicon-containing films resulting from the processes discussed above may include SiOC, SiOCN, SiNC. However, the polycarbosilazane oligomer solution may be mixed with other polymers or oligomers (co-reactants) to form films containing other elements as well such as B, Ge, Ga, Al, Zr, Hf, Ti, Nb, V, Ta. One of ordinary skill in the art will recognize that by selection of the appropriate polycarbosilazane containing formulation and co-reactants, the desired film composition may be obtained.

(77) Unless deliberately added to the disclosed silicon and carbon containing film forming compositions, the concentration of trace metals and metalloids in the silicon and carbon containing film forming composition may each range from approximately 0 ppbw to approximately 500 ppbw, preferably from approximately 0 ppbw to approximately 100 ppbw, and more preferably from approximately 0 ppbw to approximately 10 ppbw. One of ordinary skill in the art will recognize that extraction using a reagent, such as hydrofluoric, nitric or sulfuric acid, and analysis by atomic absorption spectroscopy, x-ray fluorescence spectroscopy, or similar analytical techniques may be used to determine the trace metal and metalloid concentrations.

EXAMPLES

(78) The following non-limiting examples are provided to further illustrate embodiments of the invention. However, the examples are not intended to be all-inclusive and are not intended to limit the scope of the inventions described herein.

Example 1

Synthesis of Oligomeric Aminosilanes Using TSP

(79) Synthesis of oligomeric aminosilanes using TSP was performed by a catalytic DHC reaction. The catalytic DHC reaction was conducted between TSP and liquid NH.sub.3 in the presence of a homogeneous catalyst (NH.sub.4Cl).

(80) Inside a glove box, a 60 cc stainless steel reactor equipped with a magnetic stirrer bar and a pressure gauge was charged with 1.08 g (20.1 mmol) NH.sub.4Cl and 1.81 g (15.0 mmol) of TSP. The reactor was sealed and connected to a manifold on a bench. It was frozen in liquid N.sub.2, vacuumed and 6.9 g (0.41 mol) of NH.sub.3 was condensed into it. The reactor was placed on top of a magnetic stirrer plate and gradually heated up to 80° C. while monitoring the pressure. When the pressure build up indicated accumulation of the expected amount of H.sub.2, the reactor was cooled down with liquid N.sub.2 and about 30 mmol of H.sub.2 was pumped out. Excess of NH.sub.3 was removed from the reactor cooled down to −20° C. The reactor was open in a glove box; toluene was added; the content was filtered out and the filtrate was analyzed. According to GC and NMR, the filtrate contained silazanes. Gravimetric test (removal of volatiles down to 0.5 T at 20° C.) showed the content of oligomeric aminosilanes was about 15% by weight.

Example 2

Synthesis of Polycarbosilazane Using TSCH

(81) Synthesis of polycarbosilazane using TSCH was performed by a catalytic DHC reaction (scale up). The catalytic DHC reaction was conducted between TSCH and liquid NH.sub.3 in the presence of a homogeneous catalyst (NH.sub.4Cl).

(82) Inside a glove box, a 600 cc stainless steel PARR reactor was charged with 8.2 g (0.15 mmol) NH.sub.4Cl and 18.0 g (0.136 mmol) of TSCH. The reactor was sealed and connected to a manifold on a bench. It was frozen in liquid N.sub.2, vacuumed and 72.5 g (4.3 mol) of NH.sub.3 were condensed into it. The reactor was gradually heated up to 95° C. while monitoring the pressure. When the pressure build up indicated accumulation of the expected amount of H.sub.2, the reactor was cooled down with liquid N.sub.2 and about 0.38 mol of H.sub.2 was pumped out. Excess of NH.sub.3 was removed from the reactor cooled down to −20° C. The reactor was open in a glove box; Toluene was added; the content was filtered out and the filtrate was analyzed. According to NMR and FTIR the filtrate contained polycarbosilazanes. GPC (dimodal chromatogram) test indicated weight average molecular weight (Mw) 840 Da, number average molecular weight (Mn) 780 Da, polydispersity index (PDI) 1.1, where PDI=Mw/Mn. TGA to 500° C. and 850° C. in N.sub.2 stream showed the residue of 8.9 and 8.5%, respectively (see FIG. 2).

Example 3

SiOC Low-k Film Formed by SOD Using TSCH-Containing Polycarbosilazane

(83) A Si substrate was cleaned through sonication process in isopropanol (IPA) and acetone solutions at room temperature for approximately 10 to 20 min. A SOD film formed on the substrate by using TSCH-containing polycarbosilazane was obtained following a SOD process as described above in FIG. 1. The SOD film was then prebaked at 200° C. for 5 min under N.sub.2 atmosphere and hardbaked in air for 30 min at 350° C. FIG. 3 is a FTIR spectrum comparison of pre-bake of the SOD film at 200° C. under N.sub.2 and hardbake of the prebaked SOD film at 350° C. in air for about 30 min. The FTIR results show the growth of Si—O—Si (around 1,150-950 cm.sup.1) and the reduction of Si—H stretch (at about 2,120 cm.sup.−1) after hardbaking. FIG. 4 is the low frequency region (1,500-650 cm.sup.−1) FTIR spectrum of FIG. 3. As shown, after the hardbake, Si—O—Si is growing, N—H around 1,175 cm.sup.−1 disappears and Si—C—Si at 1,360 cm.sup.−1 is maintaining, indicating N is replaced by O in the prebaked SOD film and the hardbaked SOD film contains SiOC and Si—O—Si. FIG. 5 is the high frequency region (4,000-1,500 cm.sup.−1) FTIR spectrum of FIG. 3. As shown, after the hardbake, the Si—H bond is reducing, CH.sub.2 remains but slightly shifted, N—H bonds at 3,473 cm.sup.−1 is gone, N—H bonds at 3,377 cm.sup.−1 is reduced but still exists, and Si—OH at around 3,700-3,400 cm.sup.−1 appears and no C═O bond is found, indicating N is replaced by O in the prebaked SOD film and the hardbaked SOD film contains SiOC. Since N—H bonds at 3,377 cm.sup.−1 still exists, N may remain in the hardbaked film that may contain SiOCN. The thickness and the shrinkage of the hardbaked SOD film are listed in Table 1 with an average of 3 measurements for each parameter. The thicknesses of the prebaked SOD film and the thickness of hardbaked SOD film have been measured by Ellipsometer. The FTIR peck assignments are listed in Table 2.

(84) TABLE-US-00001 TABLE 1 Film thickness (nm) Hardbake Polymer Prebake Hardbake atmosphere Shrinkage (%) TSCH 325 311 air 4.6 TSP 208 183 air 12.0

(85) TABLE-US-00002 TABLE 2 FTIR Peak Assignments Wavenumber (cm.sup.−1) Assignment 950-930 Si—H.sub.2 deformation 1,150-950.sup.  Si—O—Si phonons 1,175 —NH— deformation 1,360 CH.sub.2 bending in Si—CH.sub.2—Si 2,120 Si—H stretch 2,940-2,880 CH.sub.2 stretches 3,377 N—H stretch in Si—NH—Si 3,473 N—H stretch in Si—NH.sub.2 3,700-3,400 broad, solid phase, O—H stretch in Si—OH stretch

Example 4

SiOC Low-k Film Formed by SOD Process Using TSP-Containing Polycarbosilazane

(86) A SOD film formed by using TSP-containing polycarbosilazane was obtained following a SOD process as described above in FIG. 1. The SOD film was then prebaked at 200° C. for 5 min under N.sub.2 atmosphere and hardbaked in air for 30 min at 350° C. FIG. 6 is a FTIR spectrum comparison of the prebaked SOD film and the hardbaked SOD film. As shown, Si—O—Si peak at around 1,010 cm.sup.−1 is growing and CH.sub.2 at 1,360 cm.sup.−1 remains as desired, N—H bonds at 3,377 cm.sup.−1 is reduced but still exists, indicating part of N is replaced by O in the prebaked SOD film and the hardbaked SOD film contains SiOC and SiOCN. The thickness and the shrinkage of the hardbaked SOD formed film are listed in Table 1.

(87) Although the subject matter described herein may be described in the context of illustrative implementations to process one or more computing application features/operations for a computing application having user-interactive components the subject matter is not limited to these particular embodiments. Rather, the techniques described herein may be applied to any suitable type of user-interactive component execution management methods, systems, platforms, and/or apparatus.

(88) It will be understood that many additional changes in the details, materials, steps, and arrangement of parts, which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims. Thus, the present invention is not intended to be limited to the specific embodiments in the examples given above and/or the attached drawings.

(89) While embodiments of this invention have been shown and described, modifications thereof may be made by one skilled in the art without departing from the spirit or teaching of this invention. The embodiments described herein are exemplary only and not limiting. Many variations and modifications of the composition and method are possible and within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims which follow, the scope of which shall include all equivalents of the subject matter of the claims.