NEW LOW-K MATERIALS DERIVED BY HYDROSILYLATION AND METHODS OF USING THEM FOR DEPOSITION

Abstract

A reaction mixture for producing a film-forming polycarbosilazane polymer comprises a first compound containing at least two unsaturated groups and a second compound containing at least two SiH.sub.2 hydrosilyl functional groups, wherein the reaction mixture is capable of forming the film-forming polycarbosilazane polymer utilizing hydrosilylation of the first compound by the second compound. Also disclosed are methods of forming a silicon and carbon containing film on a substrate comprising the steps of producing a film-forming polycarbosilazane polymer by a polymerization of a reaction mixture of a first compound containing at least two unsaturated groups and a second compound containing at least two hydrosilyl functional groups, forming a solution containing the film-forming polycarbosilazane polymer, 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 on the substrate.

Claims

1. A reaction mixture for producing a film-forming polycarbosilazane polymer, the reaction mixture comprising a first compound containing at least two unsaturated groups; and a second compound containing at least two hydrosilyl functional groups, wherein the reaction mixture is capable of forming the film-forming polycarbosilazane polymer utilizing hydrosilylation of the first compound by the second compound.

2. The reaction mixture of claim 1, wherein the at least two unsaturated groups are vinyl or alkynyl group.

3. The reaction mixture of claim 1, wherein the first compound includes Tetravinylsilane, Dimethyldivinylsilane, Trivinylmethylsilane, 2,4,6-Trimethyl-2,4,6-trivinylcyclotrisilazane, 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane, and Octavinyloctasilasesquioxane.

4. The reaction mixture of claim 1, wherein the at least two hydrosilyl functional groups are at least two SiH.sub.2 groups.

5. The reaction mixture of claim 4, wherein the at least two SiH.sub.2 groups are three SiH.sub.2 groups.

6. The reaction mixture of claim 4, wherein the at least two SiH.sub.2 groups are at least two SiH.sub.3 groups.

7. The reaction mixture of claim 6, wherein the at least two SiH.sub.3 groups are three SiH.sub.3 groups.

8. The reaction mixture of claim 1, wherein the second compound is selected from Si.sub.nH.sub.m, where n>1 and m=2n+2 or 2n (cyclic), N(SiH.sub.3).sub.3, (SiH.sub.3).sub.2NSiH.sub.2N(SiH.sub.3).sub.2, (SiH.sub.3)HNSiH.sub.2N(SiH.sub.3).sub.2, (SiH.sub.2NSiH.sub.3).sub.3, HN(SiH.sub.3).sub.2, H.sub.2N(SiH.sub.3), N(SiH.sub.2Me).sub.3, H.sub.2N(SiH.sub.2Me), HN(SiH.sub.3) (SiH.sub.2Me), MeN(SiH.sub.3).sub.2, Me.sub.2N(SiH.sub.3), H.sub.2N[Si(OMe)H.sub.2], H.sub.2N[Si(OMe).sub.2H], or H.sub.2N[Si(OMe)H.sub.2].

9. The reaction mixture of claim 1, wherein the second compound is trisilylamine, N(SiH.sub.3).sub.3 (CAS No.: 13862-16-3).

10. The reaction mixture of claim 1, further comprising a catalyst selected from a metal-free or photoreactive catalyst.

11. The reaction mixture of claim 10, wherein the catalyst is an azo compound selected from 2,2-Azobis(2,4-dimethylvaleronitrile), azobisisobutyronitrile, 1,1-Azobis(cyclohexanecarbonitrile, or an organic peroxide selected from di-tert-butyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide.

12. The reaction mixture of claim 1, further comprising a solvent or a solvent mixture selected from at least one of hydrocarbons, aromatic solvents selected from toluene, xylene or mesitylene, ethers selected from a tert-butyl ethers, THF or glymes, amines selected from trialkylamine or dialkylamine.

13. The reaction mixture of claim 1, further comprising 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.

14. The reaction mixture of claim 13, 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.2 (SiH.sub.2).sub.2SiH.sub.3), trisilylamine (N(SiH.sub.3).sub.3), or trisilyamine derivatives selected from alkylamino-substituted trisilylamines of trisilylamines.

15. 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 by a polymerization of a reaction mixture of a first compound containing at least two unsaturated groups and a second compound containing at least two hydrosilyl functional groups; forming a solution containing the film-forming polycarbosilazane polymer; 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 on the substrate.

16. The method of claim 15, 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.

17. The method of claim 15, wherein the film-forming polycarbosilazane polymer is produced by hydrosilylation of the first compound by the second compound.

18. The method of claim 15, wherein the at least two unsaturated groups are vinyl or alkynyl group.

19. The method of claim 15, wherein the first compound includes Tetravinylsilane, Dimethyldivinylsilane, Trivinylmethylsilane, 2,4,6-Trimethyl-2,4,6-trivinylcyclotrisilazane, 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane, and Octavinyloctasilasesquioxane.

20. The reaction mixture of claim 15, wherein the at least two hydrosilyl functional groups are at least two SiH.sub.2 groups.

21. The reaction mixture of claim 20, wherein the at least two SiH.sub.2 groups are three SiH.sub.2 groups.

22. The reaction mixture of claim 20, wherein the at least two SiH.sub.2 groups are at least two SiH.sub.3 groups.

23. The reaction mixture of claim 22, wherein the at least two SiH.sub.3 groups are three SiH.sub.3 groups.

24. The method of claim 15, wherein the second compound is selected from Si.sub.nH.sub.m, where n>1 and m=2n+2 or 2n (cyclic), N(SiH.sub.3).sub.3, (SiH.sub.3).sub.2NSiH.sub.2N(SiH.sub.3).sub.2, (SiH.sub.3)HNSiH.sub.2N(SiH.sub.3).sub.2, (SiH.sub.2NSiH.sub.3).sub.3, HN(SiH.sub.3).sub.2, H.sub.2N(SiH.sub.3), N(SiH.sub.2Me).sub.3, H.sub.2N(SiH.sub.2Me), HN(SiH.sub.3) (SiH.sub.2Me), MeN(SiH.sub.3).sub.2, Me.sub.2N(SiH.sub.3), H.sub.2N [Si(OMe)H.sub.2], H.sub.2N [Si(OMe).sub.2H], or H.sub.2N [Si(OMe)H.sub.2].

25. The method of claim 15, wherein the second compound is trisilylamine, N(SiH.sub.3).sub.3 (CAS No.: 13862-16-3).

26. The method of claim 15, wherein the step of the producing the film-forming polycarbosilazane polymer comprises the step of adding a catalyst selected from a metal-free or photoreactive catalyst to the reaction mixture.

27. The method of claim 26, wherein the catalyst is an azo compound selected from 2,2-Azobis(2,4-dimethylvaleronitrile), azobisisobutyronitrile, 1,1-Azobis(cyclohexanecarbonitrile, or an organic peroxide selected from di-tert-butyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide.

28. The method of claim 15, further comprising the step of the forming the solution containing the film-forming polycarbosilazane polymer comprising the step of adding a solvent or a solvent mixture to the reaction mixture, wherein the solvent or the solvent mixture is selected from at least one of hydrocarbons, aromatic solvents selected from toluene, xylene or mesitylene, ethers selected from a tert-butyl ethers, THF or glymes, amines selected from trialkylamine or dialkylamine.

29. The method of 15, wherein the step of the producing the film-forming polycarbosilazane polymer 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.

30. The method of 29, 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.2 (SiH.sub.2).sub.2SiH.sub.3), trisilylamine (N(SiH.sub.3).sub.3), or trisilyamine derivatives selected from alkylamino-substituted trisilylamines of trisilylamines.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0079] For a further understanding of the nature and objects of the present invention, reference should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements are given the same or analogous reference numbers and wherein:

[0080] FIG. 1 is thermogravimetric analysis (TGA) of Low-k 1;

[0081] FIG. 2 is a FTIR spectrum (1,500-650 cm.sup.1) comparison of soft-baked, UV-cured and annealed of the SOD of SiOC low-k film formed by TSA and tetravinylsilane precursors of Example 1;

[0082] FIG. 3 is TGA of Low-k 2;

[0083] FIG. 4 is TGA of Low-k 3;

[0084] FIG. 5 is a FTIR spectrum (1,500-650 cm.sup.1) comparison of pre-baked, UV-cured and annealed of the SOD of SiOC low-k film formed by TSA and (TriVinyl-TriMethyl-Cyclo-TriSilazane) precursors of Example 3;

[0085] FIG. 6 is TGA of Low-k 4; and

[0086] FIG. 7 is a FTIR spectrum (1,500-650 cm.sup.1) comparison of pre-baked, UV-cured and annealed of the SOD of SiOC low-k film formed by TSA and (TriVinyl-TriMethyl-Cyclo-TriSiloxane) precursors of Example 4.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0087] Disclosed are silicon and carbon containing film-forming compositions comprising a polycarbosilazane containing polymer 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 or the like. Particularly, the disclosed methods are spin-on deposition (SOD) of the silicon and carbon containing film-forming composition comprising the polycarbosilazane containing formulation following pre-baking (or curing) and hardbaking processes to form a low-k dielectric film, such as a SiOC, SiOCN or SiCN film. The disclosed revers to spinnable composition, synthesis methods and application of novel silazane and/or carbosilanes composition that are useful for making dielectric films having a low dielectric constant.

[0088] The disclosed polycarbosilazane containing polymers are new low-k materials derived by hydrosilylation of a first compound containing unsaturated groups with a second compound containing hydrosilyl functional groups and the subsequent formulation of the resulting polymers. More specifically, the disclosed are preparation of polycarbosilazanes or polycarbosilazane polymers utilizing hydrosilylation of the first compound containing at least two unsaturated groups by the second compound containing at least two hydrosilyl functional groups. This methodology may be used to furnish materials for spin-coating application as low-dielectric constant thin films.

[0089] The at least two unsaturated groups in the disclosed first compound may be vinyl or alkynyl groups.

[0090] The disclosed first compounds containing at least two unsaturated groups may include Tetravinylsilane, Trivinylmethylsilane, Dimethyldivinylsilane, 2,4,6,8-Tetravinyl-2,4,6,8-tetramethylcyclotetrasilazane, 2,4,6-Trimethyl-2,4,6-trivinylcyclotrisilazane, 2,4,6,8-Tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane, 1,3,5-Trivinyl-1,3,5-trimethylcyclotrisiloxane, vinyltriisopropenoxysilane and Octavinyloctasilasesquioxane.

[0091] The at least two hydrosilyl functional groups in the disclosed second compound are at least two SiH.sub.2 groups, preferably three SiH.sub.2 groups, more preferably at least two SiH.sub.3 groups, even more preferably three SiH.sub.3 groups. The disclosed second compound containing at least two SiH.sub.2 groups may be i) no bridges, such as a disilanes RSiH.sub.2SiH.sub.2R; ii) bridged by Nitrogen, such as (SiH.sub.3).sub.3N, (MeH.sub.2Si).sub.3N, SiH.sub.3N(Me)-SiH.sub.3, etc.; and iii) bridged by C.sub.xH.sub.y chain, such as SiH.sub.3CH.sub.2SiH polycarbosilazane containing polymer, SiH.sub.3CH.sub.2CH.sub.2SiH.sub.3, (SiH.sub.3).sub.3CH, etc. In this way, SiC.sub.xH.sub.ySi backbone of the resulting polycarbosilazane containing polymer is maintained and remains intack under the hydrosilylation conditions.

[0092] Exemplary disclosed second compound containing at least two hydrosilyl functional groups include Si.sub.nH.sub.m, where n>1 and m=2n+2 or 2n (cyclic), N(SiH.sub.3).sub.3, (SiH.sub.3).sub.2NSiH.sub.2N(SiH.sub.3).sub.2, (SiH.sub.3)HNSiH.sub.2N(SiH.sub.3).sub.2, (SiH.sub.2NSiH.sub.3).sub.3, HN(SiH.sub.3).sub.2, H.sub.2N(SiH.sub.3), N(SiH.sub.2Me).sub.3, H.sub.2N(SiH.sub.2Me), HN(SiH.sub.3) (SiH.sub.2Me), MeN(SiH.sub.3).sub.2, Me.sub.2N(SiH.sub.3), H.sub.2N[Si(OMe)H.sub.2], H.sub.2N[Si(OMe).sub.2H], H.sub.2N[Si(OMe)H.sub.2], or the like.

[0093] In some embodiments, the disclosed second compound containing at least two hydrosilyl functional groups is trisilylamine (TSA) N(SiH.sub.3).sub.3 (CAS No. 13862-16-3).

[0094] The disclosed synthesis methods comprise mixing of the first compound that contains at least two unsaturated groups with the second compound that contains at least two SiH.sub.2 groups in liquid phase and possibly, with a catalyst, which is preferably a metal-free or photoreactive catalyst, thereby resulting in a polycarbosilazane polymer.

[0095] The disclosed silicon and carbon containing film-forming composition contains the resulting or synthesized polycarbosilazane polymer according to the disclosed synthesis methods and at least a solvent, the combination of which may be used as a coating solution which may then be applied to a substrate, ideally by a spin-coating technique such as a spin-on coating, spray coating, dip coating, slit coating technique, or the like.

[0096] In one embodiment of the resulting polycarbosilazane polymer, Scheme 1, trisilylamine (TSA) moieties are bridged with other TSA moieties by a carbon frame-work resulting in ethylene-bridged polycarbosilazanes. The resulting ethylene-bridged polycarbosilazanes may be formulated and the resulting polymer formulation may be applied to the coating solution as described above. Exemplary ethylene-bridged polycarbosilazanes of Scheme 1 includes: [0097] a. Low-k 1: TSA mixes with tetravinylsilane forming Low-k 1 polymer:

##STR00001## [0098] b. Low-k 2: TSA mixes with trivinylmethylsilane forming Low-k 2 polymer:

##STR00002## [0099] c. Low-k 3: TSA mixes with trivinylmethylsilane and

[0100] Diisopropylaminotrisilylamine forming a Low-k 3 polymer:

##STR00003##

[0101] In another embodiment of the resulting polycarbosilazane polymer, Scheme 2, TSA mixes with cyclic silazane possessing vinyl groups on the silicon. TSA moieties are bridged with other TSA moieties by a cyclic silazane carbon frame-work resulting in ethylene-bridged cyclic polycarbosilazanes. The resulting ethylene-bridged cyclic polycarbosilazanes may be formulated and the resulting polymer formulation may be applied to the coating solution as described above. Exemplary ethylene-bridged cyclic polycarbosilazanes of Scheme 2 includes: [0102] a. Low-k 4: TSA mixes with 2,4,6,8-Tetravinyl-2,4,6,8-tetramethylcyclotetrasilazane forming a Low-k 4 polymer:

##STR00004## [0103] b. Low-k 5: TSA mixes with 2,4,6-Trimethyl-2,4,6-trivinylcyclotrisilazane forming a Low-k 5 polymer:

##STR00005##

[0104] In another embodiment of the resulting polycarbosilazane polymer, Scheme 3, TSA mixes with cyclic siloxanes possessing vinyl groups on the silicon. TSA moieties are bridged with other TSA moieties by a cyclic siloxane carbon frame-work resulting in ethylene-bridged cyclic polycarbosilazanes. The resulting ethylene-bridged cyclic polycarbosilazanes may be formulated and the resulting formulation may be applied to the coating solution as described above. Exemplary ethylene-bridged cyclic polycarbosilazanes of Scheme 3 includes: [0105] a. Low-k 6: TSA mixes with 2,4,6,8-Tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane forming a Low-k 6 polymer:

##STR00006## [0106] b. Low-k 7: TSA mixes with 1,3,5-Trivinyl-1,3,5-trimethylcyclotrisiloxane forming a Low-k 7 polymer:

##STR00007## [0107] c. A further example of a vinyl functionalized substrate that could undergo an analogous chemical reaction with TSA is octavinyloctasilasesquioxane shown below.

##STR00008##

[0108] The catalyst used herein preferably is a metal-free or photoreactive catalyst, for example, azo compounds such as 2,2-azobis(2,4-dimethylvaleronitrile), azobisisobutyronitrile, 1,1-Azobis(cyclohexanecarbonitrile but is not limited to. Other molecules such as organic peroxides may also be used as catalyst here, for example di-tert-butyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide but are not limited to.

[0109] The reaction temperature range could be from approximately 0 C. to approximately 100 C., preferably from approximately 20 C. to approximately 80 C., more preferably from approximately 50 C. to approximately 60 C., even more preferably approximately 55 C. In some embodiments, the temperature range may be set depending on the catalyst suitable temperature.

[0110] The preferred reaction pressure range is about from 0 to 20 psig.

[0111] 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.

[0112] 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 of SiC bonds.

[0113] The disclosed silicon and carbon containing film-forming composition typically contains 1-20% by weight of the non-volatile polycarbosilazane 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 as 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, or the like.

[0114] 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.2 (SiH.sub.2).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:

##STR00009##

[0115] 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.

[0116] 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.

[0117] Spin-on-deposition (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 the 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., which depends 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 may be controlled by the annealing temperature, the composition of the annealing atmosphere, and by the annealing time. Alternatively, the as-deposited 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.

[0118] The silicon-containing films resulting from the processes discussed above may include SiOC, SiOCN, SINC. However, the polycarbosilazane polymer solution may be mixed with other polymers (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 judicial selection of the appropriate polycarbosilazane containing formulation and co-reactants, the desired film composition may be obtained.

[0119] 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

[0120] A more detailed description of the disclosed methods through examples is provided as follows. However, the disclosed methods is not limited to presented examples in any way and process conditions, process gas mixture, combination and proportion of gases in the gas mixture, workpiece and plasma etching chamber itself may be altered.

[0121] In the following Examples, the primary plasma etching source may be a CCP plasma but may also include other sources such as ICP, microwave, ECR, etc. The plasma may be used in a continuous source or as a pulsed plasma of a certain frequency and duty cycle. Additional fluorocarbon gases may be added to slightly tune the etching performance. Additional inert gases may be added such as Kr, Xe, Ne, Ne as well as hydrogen source gases such as H.sub.2, and hydrocarbons. The mask material may include TiN or other metal nitride materials, SiN, Si, carbon materials, or the like.

Example 1 SiOC Low-k Film Formed by SOD Using Low-k 1

Preparation of Low-k 1 According to Scheme 1

##STR00010##

[0122] A 100 mL glass pressure tube equipped with a magnetic stir bar and Teflon plug was charged with tetravinylsilane, TSA, catalyst and solvent. The mixture was stirred, heated and then allowed to cool to room temperature. Volatile components were removed en vacuo to furnish a colorless, viscous oil. Thermogravimetric analysis (TGA) (25-500 C. 10 C./min) suggested 43.7% of non-volatile residue (NVR) (FIG. 1). Analyses by .sup.1H, .sup.29Si and .sup.13C NMR (not shown) were consistent with the expected structure type as the major components.

SiOC Low-k Film Formed by SOD Using Low-k 1

[0123] A thin film was formed by SOD using the product of a polymer formulation Low-k 1 made by TSA and tetravinylsilane precursors. The SOD film was spun at 2000 rpm, for 60 sec, using a spin coater (Laurel WS-650 Mz-8NPPB). The SOD formed film was then soft baked at 200 C. for 5 min under compressed air atmosphere and UV cured at 1000 mJ/cm.sup.2 in compressed air at room temperature (using UV lamp, wavelength 172 nm). Finally, the SOD film was annealed at 600 C. for 5 min in N.sub.2. FIG. 2 is a FTIR spectrum (1,500-650 cm.sup.1) comparison of soft-baked, UV-cured and annealed of the SOD of SiOC low-k film formed by TSA and tetravinylsilane precursors. As shown, the SiH bond (at 2150 cm.sup.1) are converted into SiOH after UV-cure and further converted into SiOSi around 1,150-950 cm.sup.1 after anneal. Thus, Si(CH.sub.2).sub.2Si backbone structure is maintained.

TABLE-US-00001 TABLE 1 FTIR Peak Assignments from FIG. 2 Wavenumber (cm.sup.1) Assignment 950-930 SiH.sub.x bending 1,150-950 SiOSi stretch 1,175 NH deformation 1260 CH.sub.3 bending in SiCH.sub.3 1,360 CH.sub.2 bending in SiCH.sub.2Si 1400 CH.sub.2 bending in Si(CH.sub.2).sub.2Si 2,120-2150 SiH.sub.x stretch 2,940-2,880 CH.sub.x stretches 3,377 NH stretch in SiNHSi 3,473 NH stretch in SiNH.sub.2 3,700-3,400 broad, OH stretch in SiOH stretch (free and H-bonded)

[0124] A Scanning Electron Microscopy (SEM) image of a gap filled trench after annealing was measured (not shown). The gap fill is performed on a Si pattern substrate with a SiO.sub.A liner. The pattern structure has an aspect ratio of 10:1 (height 1.3 m and width 130 nm). Low-k 1 formulation exhibits a complete gap filling, without defects, that is, no delamination, crack or voids are observed.

[0125] Electrical properties of the SOD film after annealing were collected using a mercury probe, the dielectric constant k is 3.1 (at the frequency of 1 MHZ).

Example 2 SiOC Low-k Film Formed by SOD Using Low-k 2

Preparation of Low-k 2 According to According to Scheme 1

##STR00011##

[0126] A 100 mL glass pressure tube equipped with a magnetic stir bar and Teflon plug was charged with Trivinylmethylsilane, TSA, catalyst and solvent. The mixture was stirred, heated and then allowed to cool to room temperature. Volatile components were removed en vacuo to furnish a colorless, viscous oil. Thermogravimetric analysis (25-500 C. 10 C./min) suggested 63.2% of non-volatile residue (NVR) (FIG. 3). Analysis by .sup.1H, .sup.29Si and .sup.13C NMR (not shown) were consistent with the expected structure type as the major component.

SiOC Low-k Film Formed by SOD Using Low-k 2

[0127] A thin film was formed by SOD using a polymer formulation Low-k 2 made by TSA and trivinylmethylsilane precursors. The SOD film was spun at 2000 rpm, for 60 sec, using a spin coater Laurel WS-650 Mz-8NPPB. The SOD formed film was then prebaked at 200 C. for 5 min under N.sub.2 atmosphere and UV cured at 1000 mJ/cm.sup.2 in compressed air at room temperature (using UV lamp, wavelength 172 nm). Finally the SOD film was annealed at 600 C. for 5 min in N.sub.2.

[0128] A SEM image of the gap filled trench after annealing was taken (not shown). The gap fill is performed on a Si pattern substrate with a SiO.sub.2 liner. The pattern structure has an aspect ratio of 10:1 (height 1.3 m and width 130 nm). Low-k 2 formulation exhibits a complete gap filling, without defects, that is, no delamination, crack or voids are observed.

[0129] Electrical properties of the SOD film after annealing were collected using a mercury probe, the dielectric constant k is 3.0 (at the frequency of 1 MHZ). Mechanical properties were measured by nanoindentation: after annealing the Young's Modulus measured is 14 GPa and the hardness is 1.2 GPa.

Example 3 SiOC Low-k Film Formed by SOD Using Low-k 5

Preparation of Low-k 5 According to Scheme 2

##STR00012##

[0130] A 100 mL glass pressure tube equipped with a magnetic stir bar and Teflon plug was charged with 2,4,6-Trimethyl-2,4,6-trivinylcyclotrisilazane, TSA, catalyst and solvent. The mixture was stirred, heated and then allowed to cool to room temperature. Volatile components were removed en vacuo to furnish a colorless, viscous oil. Thermogravimetric analysis (25-500 C. 10 C./min) suggested 91.0% of non-volatile residue (NVR) (FIG. 4). Analysis by .sup.1H and .sup.29Si NMR (not shown) were consistent with the expected structure type as the major component together with a minor component with some vinyl groups remaining unreacted.

SiOC Low-k Film Formed by SOD Using Low-k 5

[0131] A thin film was formed by SOD using a polymer formulation Low k 5 made by TSA and 2,4,6-Trimethyl-2,4,6-trivinylcyclotrisilazane precursors. The film was spun at 2000 rpm, for 60 sec, using a spin coater (Laurel WS-650 Mz-8NPPB). The SOD formed film was then soft baked at 200 C. for 5 min under compressed air atmosphere and UV cured at 1000 mJ/cm.sup.2 in compressed air at room temperature (using UV lamp, wavelength 172 nm). Finally the SOD film was annealed at 600 C. for 5 min in N.sub.2. FIG. 5 is a FTIR spectrum (1,500-650 cm.sup.1) comparison of pre-baked, UV-cured and annealed of the SOD of SiOC low-k film formed by TSA and 2,4,6-Trimethyl-2,4,6-trivinylcyclotrisilazane precursors. As shown, the SiH bond (at 2150 cm.sup.1) are converted into SiOH after UV-cure and further converted into SiOSi around 1,150-950 cm.sup.1 after anneal. Si(CH.sub.2).sub.2Si backbone structure is maintained.

[0132] A SEM image of the gap filled trench after annealing was taken (not shown). The gap fill is performed on a Si pattern substrate with a SiO.sub.2 liner. The pattern structure has an aspect ratio of 10:1 (height 1.3 m and width 130 nm). Low-k 3 formulation exhibits a complete gap filling, without defects, that is, no delamination, crack or voids are observed.

[0133] Electrical properties of the SOD film after annealing were collected using a mercury probe, the dielectric constant k is 2.7 (at the frequency of 1 MHZ). Mechanical properties were measured by nanoindentation: after annealing the Young's Modulus measured is 10 GPa and the hardness is 1.2 GPa.

Example 4 SiOC Low-k Film Formed by SOD Using Low-k 7

Preparation of Low-k 7 According to Scheme 3

##STR00013##

[0134] A 100 mL glass pressure tube equipped with a magnetic stir bar and Teflon plug was charged with 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane, TSA, catalyst and solvent. The mixture was stirred, heated and then allowed to cool to room temperature. Volatile components were removed en vacuo to furnish a colorless, viscous oil. Thermogravimetric analysis (25-500 C. 10 C./min) suggested 57.9% of non-volatile residue (NVR) (FIG. 6). Analysis by .sup.1H and .sup.29Si NMR (not shown) were consistent with the expected structure type as the major component together with a minor component with some vinyl groups remaining unreacted.

SiOC Low-k Film Formed by SOD Using Low-k 7

[0135] A thin film was formed by SOD using a polymer formulation Low k 4 made by TSA and 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane precursors. The SOD film was spun at 2000 rpm, for 60 sec, using a spin coater Laurel WS-650 Mz-8NPPB. The SOD formed film was then soft-baked at 200 C. for 5 min under compressed air atmosphere and UV cured at 1000 mJ/cm.sup.2 in compressed air at room temperature (using UV lamp, wavelength 172 nm). Finally, the SOD film was annealed at 600 C. for 5 min in N.sub.2. FIG. 7 is a FTIR spectrum (1,500-650 cm.sup.1) comparison of pre-baked, UV-cured and annealed of the SOD of SiOC low-k film formed by TSA and TriVinyl-TriMethyl-Cyclo-TriSiloxane precursors. As shown, the SiH bond (at 2150 cm.sup.1) are converted into SiOH after UV-cure and further converted into SiOSi around 1,150-950 cm.sup.1 after anneal. Si(CH.sub.2).sub.2Si backbone structure is maintained.

[0136] A SEM image of the gap filled trench after annealing was measured (not shown). The gap fill is performed on a Si pattern substrate with a SiO.sub.2 liner. The pattern structure has an aspect ratio of 10:1 (height 1.3 m and width 130 nm). Low-k 4 formulation exhibits a complete gap filling, without defects, that is, no delamination, crack or voids are observed. Electrical properties of the SOD film after annealing were collected using a mercury probe, the dielectric constant k is 2.8 (at the frequency of 1 MHZ).

[0137] Table 2 is a summary of the performance of each formulation (each data is an as average of at least 3 measurements). Shrinkage has been calculated using the thickness difference between anneal and prebake measured by Ellipsometer.

[0138] Electrical properties have be measured using a mercury robe. And the mechanical properties have been measured using a nanoindentor, KLA Tencor iNano.

TABLE-US-00002 TABLE 2 Summary Shrinkage k-value (@ Young's Modulus Hardness Polymer (%) 1 MHz) (GPa) (GPa) Low-k 1 18% 3.1 n/a n/a Low-k 2 20% 3.0 14 1.2 Low-k 5 10% 2.7 10 1.2 Low-k 7 10% 2.8 n/a n/a

[0139] 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.

[0140] 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.