KR20040051326A - Siloxane-Based Resin and Method for Forming a Low Dielectric Patterned Film by Using the Same - Google Patents

Abstract

PURPOSE: A siloxane-based resin and a method for forming a low dielectric pattern layer by using the resin are provided, to omit the processes for forming an insulating layer and a pattern for simplifying the process by using a siloxane-based resin acting as a low dielectric substance and a photoresist. CONSTITUTION: The siloxane-based resin is obtained by hydrolyzing and condensation polymerizing a silane compound represented by SiR1X2X2X3, a silane compound represented by SiR2X1X2X3, and/or a silane compound represented by X3X2X1Si-(R3)-SiX1X2X3 in an organic solvent in the presence of a catalyst and water, wherein R1 is an acid and heat-labile group-substituted alkylate group of C5-C10, cycloalkylate group or arylate group; R2 is H, an alkyl group of C1-C3, a cycloalkyl group of C3-C10 or an aryl group of C6-C15; R3 is an alkyl or oxyalkyl group of C1-C3, a cycloalkyl or oxycycloalkyl group of C3-C10, or an aryl or oxyaryl group of C6-C15; and X1, X2 and X3 are independently H, an alkyl group of C1-C3, an alkoxy group of C1-C4, or a halogen atom, and at least two among them are an alkoxy group of C1-C4 or a halogen atom.

Description

Siloxane-Based Resin and Method for Forming a Low Dielectric Patterned Film by Using the Same}

The present invention relates to a novel siloxane-based resin and a method of forming a low dielectric pattern film using the same, and more particularly, hydrolyzing one silane compound and one or two other silane compounds having an acid and heat labile functional group. And dissolving the siloxane resin prepared by condensation polymerization, and dissolving the resin in an organic solvent together with a photoacid generator, coating the substrate on the substrate, and then heat-treating the pattern obtained by exposure and development. It is about.

As the degree of integration increases in the semiconductor field, device performance depends on the wiring speed, and in order to reduce the resistance and the electric capacity in the wiring, the accumulation capacity of the interlayer insulating film must be lowered. To this end, attempts have been made to use a low dielectric constant material as an interlayer insulating film material. For example, U.S. Patent No. 3,615,272, 1 - 4,399,266 and No. 4,999,397 arc in the semiconductor as the interlayer insulating material, is available in the SiO ₂ instead of dielectric constant 4.00 that was used in (Chemical Vapor Deposition) conventional CVD process SOD (Spin On Deoposition) A polysilsesquioxane having a dielectric constant of about 2.5 to 3.1 is disclosed, and US Patent No. 5,965,679 discloses a polyphenylene which is an organic polymer having a dielectric constant of about 2.65 to 2.70. However, they are not all low enough for high speed devices that require very low dielectric constants below 2.50.

For this reason, various attempts have been made to insert air having a dielectric constant of 1.0 at the nano level in various organic and inorganic matrices. For example, porous silica by the sol-gel method using tetraethoxysilane (TEOS) and the appropriate porogen.

(SiO ₂ ) method of producing a dendrimer type porogen of a vinyl polymer of a constant size that can be decomposed by heat, and then mixed with a predetermined amount of the organic and inorganic matrix After forming a thin film and decomposing the porogen at a high temperature to form nano-level pores, a method of obtaining a very low dielectric constant thin film is disclosed in US Pat. Nos. 6,107,357 and 6,093,636, respectively. However, in the case of the conventional method, the size of the generated pores is 50 ~ 100 Å level, there is a problem that the distribution in the matrix of the pores is uneven.

In addition, the conventional method for forming a semiconductor interlayer insulating film has a disadvantage in that the process is complicated because a step of further applying a photoresist layer on the insulating film, exposing, developing, and dry etching is required for pattern formation.

Accordingly, the present invention is to solve the problems of the prior art as described above, using a silane compound having an acid and heat labile functional group and other silane compound as a comonomer, serves as a photoresist and uniform nano pores through heat treatment An object of the present invention is to provide a method of polymerizing a siloxane-based resin capable of forming a polymer and forming a low dielectric pattern film using the resin.

That is, one aspect of the present invention provides a method for preparing an organic compound comprising (a) a silane compound having a structure of Formula 1, (b) a silane compound having a structure of Formula 2, and / or (c) a silane compound having a structure of Formula 3 A siloxane based resin prepared by hydrolysis and polycondensation in the presence of a catalyst and water in a solvent is provided:

[Formula 1]

SiR ₁ X ₁ X ₂ X ₃

Where

R ₁ is a C ₅ to C ₁₀ alkylate substituted with an acid and heat labile functional group

group, cycloalkyate group or arylate group

group);

X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, an alkyl group of C _{1 to} C ₃ , an alkoxy group of C _{1 to} C ₄ , or a halogen group, At least two of them are C ₁ to C ₄ alkoxy groups or halogen groups;

[Formula 2]

SiR ₂ X ₁ X ₂ X ₃

Where

R ₂ is a hydrogen atom, a C ₁ -C ₃ alkyl group, a C ₃ -C ₁₀

A cycloalkyl group or a C _{6 to} C ₁₅ aryl group;

X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, an alkyl group of C _{1 to} C ₃ , an alkoxy group of C _{1 to} C ₄ , or a halogen group, At least two of them are C ₁ to C ₄ alkoxy groups or halogen groups;

[Formula 3]

X ₃ X ₂ X ₁ Si- (R ₃ ) -SiX ₁ X ₂ X ₃

Where

R ₃ is a C ₁ to C ₃ alkyl group or an oxyalkyl group,

C ₃ -C ₁₀ cycloalkyl group or oxycycloalkyl group

group) or an aryl group or an oxyaryl group of C _{6 to} C ₁₅ ;

X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, an alkyl group of C _{1 to} C ₃ , an alkoxy group of C _{1 to} C ₄ , or a halogen group, at least one of which is an alkoxy group or halogen group of the C ₁ ~C _4.

Another aspect of the present invention comprises the steps of dissolving the siloxane resin in an organic solvent with a photoacid generator to provide a coating solution; Applying the coating solution on a silicon substrate and then pre-baking to deposit a resin film on the substrate; Exposing the resin film through a photomask and then drying the post-exposure baking; Developing the resin film to express a pattern; And it provides a low dielectric pattern film forming method comprising the step of heat-treating the pattern.

Hereinafter, the siloxane resin of the present invention will be described in more detail.

The siloxane resin of the present invention is a binary or ternary copolymer prepared by hydrolyzing and condensation polymerizing one silane compound and one or two other silane compounds having an acid and heat labile functional group in an organic solvent in the presence of a catalyst and water. It is characterized by a chain.

In the present invention, the silane compound having an acid and heat labile functional group means a silane compound having a structure of Formula 1 below:

SiR ₁ X ₁ X ₂ X ₃

Where

R ₁ is a C ₅ to C ₁₀ alkylate group, a cycloalkyate group or an arylate group substituted with an acid and heat labile functional group

group);

X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, an alkyl group of C _{1 to} C ₃ , an alkoxy group of C _{1 to} C ₄ , or a halogen group, At least two of them are C ₁ to C ₄ alkoxy groups or halogen groups.

The acid and heat labile functional group is a functional group that can be liberated and decomposed by an acid or heat from the compound of Formula 1, and is preferably selected from the group consisting of an ester group, a carbonate group, an acetal group, and a ketal group.

By using the silane compound having an acid labile functional group as an essential monomer, the resulting siloxane resin of the present invention is an alkali used in a conventional photolithography process between the exposed portion and the non-exposed portion during exposure in the presence of a photoacid generator. The difference in solubility in the developing solution is large, which in itself has the function of a photoresist. In addition, since the silane compounds of Formula 1 have a functional group that can be decomposed by heat, the resin of the present invention polymerized therefrom is coated on a substrate, and the resulting resin film is nano-over the entire film upon heat treatment at a predetermined temperature range. -The pores of the size are formed uniformly.

Preferred examples of the silane compound having the structure of Formula 1 include (t-butyl 5-norbornyl-2-carbonate) triethoxysilane and (t-butyl 2-trifluoromethyl-3-propanei

Tri) ethoxysilane, (4-methoxymethyloxy-4,4-ditrifluoromethyl-1-butyl) trimethoxysilane, (4- (methoxymethyloxy-2- (1,3- Ditrifluoromethyl) propyl) benzyl-1-ethyl) trimethoxysilane and the like. Among them, (t-butyl 5-norbornyl-2-carbonate) triethoxysilane or (t-butyl 2- The use of trifluoromethyl-3-propanoate) triethoxysilane is more preferred in view of the ease of pore size control during heat treatment.

As a comonomer to be polymerized together with the silane compound of Formula 1 to obtain the siloxane resin of the present invention, a silane compound having the structure of Formula 2 and / or Formula 3 is used:

SiR ₂ X ₁ X ₂ X ₃

Where

R ₂ is a hydrogen atom, a C ₁ -C ₃ alkyl group, a C ₃ -C ₁₀

A cycloalkyl group or a C _{6 to} C ₁₅ aryl group;

X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, an alkyl group of C _{1 to} C ₃ , an alkoxy group of C _{1 to} C ₄ , or a halogen group, At least two of them are C ₁ to C ₄ alkoxy groups or halogen groups;

X ₃ X ₂ X ₁ Si- (R ₃ ) -SiX ₁ X ₂ X ₃

Where

R ₃ is a C ₁ to C ₃ alkyl group or an oxyalkyl group,

C ₃ -C ₁₀ cycloalkyl group or oxycycloalkyl group

group) or an aryl group or an oxyaryl group of C _{6 to} C ₁₅ ;

X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, an alkyl group of C _{1 to} C ₃ , an alkoxy group of C _{1 to} C ₄ , or a halogen group, at least one of which is an alkoxy group or halogen group of the C ₁ ~C _4.

The silane compound of Formula 2 or 3 may also have a functional group that can be decomposed by heat, in which case contributes to the formation of nano-sized pores throughout the film when heat-treating the resin film of the resin of the present invention.

Preferred examples of the silane compound having the structure of Formula 2 include methyltriethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, cyclohexyltriethoxysilane, trichlorosilane, trichlorosilylbutyronitrile , Triethoxysilylethyl acetate, triethoxy (3,3,3-trifluoropropyl) silane, and the like. Preferred examples of the silane compound having the structure of Formula 3 include 1,2-bis (tri Methoxysilyl) ethane, 1,4-bis (trimethoxysilyl) butane, 1,6-bis (trimethoxysilyl) hexane, 1,4-bis (trimethoxysilyl) cyclohexane, 1,5- Bis (trimethoxysilyl) -3-oxypentane, 1,4-bis (trimethoxyethylsilyl) benzene, 1,1'-bis (trimethoxyethylsilyl) benzyl ether and the like.

When preparing the siloxane resin of the present invention, the compound of formula 1 (hereinafter referred to as monomer (a)) and the compound of formula (2) (hereinafter referred to as monomer (b)) or the compound of formula (3) In the case of binary copolymerization of (c), at least 0.1 mol% of each monomer is used, and the molar ratio between the two monomers is (a) :( b) (or (c)) = 0.25 to 1: 1-4 It is preferred in view of the mechanical strength of the final polymer. On the other hand, in the case of terpolymerizing monomer (a), monomer (b) and monomer (c), at least 0.1 mol% or more of each monomer is likewise used, and the molar ratio between the three monomers is (a) :( b) :( c ) =

0.25-1: 0.5-2: 0.5-2 are preferable at the point of the pattern formation ability of a final polymer.

As the organic solvent required for preparing the siloxane resin of the present invention, an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent, a ketone solvent, an ether solvent, an acetate solvent, an alcohol solvent, a silicone solvent, or a mixture thereof may be used. .

The type of catalyst used for preparing the siloxane resin of the present invention is not particularly limited, but hydrochloric acid, nitric acid, and benzene sulfonic acid

sulfonic acid, oxalic acid, formic acid, potassium hydroxide

(potassium hydroxide), sodium hydroxide, triethylamine

It is preferable to use at least one selected from triethylamine, sodium bicarbonate, and pyridine. The amount of catalyst used is 0.0001 per equivalent of the total monomers (monomer (a) + monomer (b) or monomer (c) for binary polymerization, or monomer (a) + monomer (b) + monomer (c)) for three-way polymerization). It is preferable that it is -1 equivalent.

The amount of water used for the hydrolysis reaction and the polycondensation reaction to obtain the resin of the present invention is preferably 0.1 to 1000 equivalents per 1 equivalent of the total monomers, the reaction is at a temperature of 0 to 200 ℃, preferably 50 to 110 ℃ , 0.1 to 100 hours, preferably 3 to 48 hours.

The siloxane resin of the present invention thus prepared has a weight average molecular weight of 3,000 to 100,000, preferably 5,000 to 30,000.

Hereinafter, a method of forming a low dielectric pattern film using the siloxane resin of the present invention will be described in more detail.

The coating solution including the siloxane resin of the present invention is prepared by dissolving the siloxane resin and 1 to 10 parts by weight of a photoacid generator per 100 parts by weight of the resin in a suitable organic solvent, wherein the amount of the solvent is easy to dissolve the resin on the substrate. It should be sufficient to be applied, and the final concentration of the solids (resin + photoacid generator) in the coating solution is preferably 0.1 to 80% by weight.

In the present invention, as the photo acid generator (triarylsulfonium salt), diaryliodonium salt (diaryliodonium salt) and sulfonate

`Crab, triphenylsulfonium triflate, triphenylsulfonium antimonate, diphenylyodonium triflate

(diphenyliodonium triflate), diphenyliodonium antimonate

antimonate), methoxydiphenyliodonium

triflate), di-t-butyldiphenyliodonium triflate (di-t-butyldiphenyliodonium

triflate), 2,6-dinitrobenzyl sulfonate, pyrogallol tris (alkylsulfonate), N-hydroxysuccinimide triflate (N-hydroxysuccinimide triflate), norbornene-dicarboximide-triflate, triphenylsulfonium nonaplate

(triphenylsulfonium nonaflate), diphenyliodonium nona plate

nonaflate), methoxydiphenyliodonium

nonaflate), di-t-butyldiphenyl iodonium nonaplate (di-t-butyldiphenyliodonium

onaflate), N-hydroxysuccinimide nonaflate, norbornene-dicarboximide-nonaflate,

Riphenylsulfonium perfluorooctanesulfonate (PFOS) (triphenylsulfonium

erfluorooctanesulfonate), diphenyliodonium PFOS, methoxydiphenyliodonium PFOS, di-t-butyldiphenyliodonium triflate, N-hydroxysuccinate Mid PFOS (N-

ydroxysuccinimide PFOS), and norbornene-dicarboximide PFOS (norbornene-

Use one or more selected from the group consisting of icarboximide PFOS.

The type of the organic solvent used for preparing the coating solution is not particularly limited, but aliphatic hydrocarbon solvents such as cyclohexanone, decahydronaphthalene, and octane

aliphatic hydrocarbon solvent); Aromatic hydrocarbon solvents such as anisole, mesitylene and xylene; Methyl isobutyl ketone, 1-methyl-2-pyrrolidinone (1-1methyl-2-

ketone-based solvents such as pyrrolidinone and acetone; Ether-based solvents such as tetrahydrofuran and isopropyl ether; Ethyl acetate, butyl

Acetate-based solvents such as acetate (butyl acetate) and propylene glycol methyl ether acetate; Isopropyl alcohol, butyl alcohol, octyl

Alcohol-based solvents such as alcohol (octyl alcohol); Silicon-based solvents such as hexamethyldisiloxane, octamethyltrisiloxane, and decamethyltetrasiloxane; Or mixtures thereof.

The coating solution of the present invention prepared as described above, but is not limited to spin coating, dip coating, spray coating, flow

By conventional coating methods such as flow coating, screen printing and the like, the coating is preferably applied on the substrate with a thickness of approximately 0.1 to 0.5 탆 by spin coating. The appropriate coating thickness is determined by the type of light source used in the subsequent exposure step.

When application of the coating liquid is completed, the organic solvent is evaporated from the substrate to deposit a resin film on the substrate. At this time, as the evaporation method, a simple air drying method such as exposing the coated substrate to the ambient environment, a method of applying a vacuum in a subsequent drying step, or a method of weakly heating at a temperature of 100 ° C. or less may be used.

After evaporating the organic solvent, pre-baking is carried out at 120 to 140 ° C. for 60 to 90 seconds, at which time the exact drying temperature depends on the type of siloxane resin.

Subsequent to pre-drying, the substrate is exposed with KrF (248 nm), ArF (193 nm) or F2 (157 nm) excimer laser, the next-generation exposure source, followed by post exposure baking (PEB) for 15-120 seconds at a temperature of 90-140 ° C. do. Then, the exposed resin film was developed for 30 to 120 seconds using an alkaline developer, preferably 2.38 wt% TMAH (tetramethylammonium hydroxide) solution to obtain a resist pattern. By setting the exposure amount at about ³ to 60 mJ / cm ² , 0.10 to 0.5 μm line and spaces pattern can be obtained.

When the pattern formed as described above is heated to a temperature at which a thermally unstable functional group, that is, R ₁ of Formula 1, can be pyrolyzed, preferably 150 to 600 ° C, more preferably 200 to 450 ° C, there is no cracking. An insoluble film is formed. In the above, the crack-free coating refers to a coating in which any crack visible to the naked eye is not observed when observed with an optical microscope at 1000 magnification, and an insoluble coating is essentially essential for any organic solvent that can be used to prepare the coating solution. Means a film that does not dissolve. The atmosphere during the heat treatment may be an inert gas (nitrogen or argon) atmosphere or a vacuum atmosphere. The heat treatment time can last up to 10 hours, preferably 30 minutes to 1 hour. Through such a heat treatment step, the nano pores are uniformly formed in the polymer matrix composed of the siloxane-based resin of the present invention to provide a pattern thin film having an extremely low dielectric constant (k≤2.5), the thin film is an interlayer insulating film of a semiconductor device Very useful as

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the following examples are for illustrative purposes only and are not intended to limit the present invention.

Example 1 Resin Synthesis

After quantifying each of the silane monomers as shown in Table 1 below, the mixture was diluted with 45 ml of tetrahydrofuran and added to the flask, and the flask was lowered to -78 ° C. After adding 4.3 ml of 0.001 M hydrochloric acid solution and 3.5 ml of distilled water at -78 ° C slowly, the temperature was gradually raised to 70 ° C, and the reaction proceeded for 16 hours. After the reaction mixture was transferred to a separatory funnel, 90 ml of diethyl ether was added, washed three times with 50 ml of water each time, and volatiles were removed under reduced pressure to obtain a polymer in the form of a white powder. The polymer was dissolved in a small amount of isopropyl alcohol, and the solution was filtered through a syringe filter having a pore diameter of 0.2 μm to remove fine powder and other foreign matter, taking only a clear filtrate portion, and then slowly adding water. At this time, the resulting white powder and the solution portion (isopropyl alcohol and water mixed solution) were separated, and the white powder was dried under reduced pressure of 0.1 Torr while maintaining the temperature at 0 to 5 ° C. to obtain a fractionated siloxane resin. It was. The amount of monomer, catalyst, water and siloxane resins used in each resin synthesis are shown in Table 1 together with the weight average molecular weight (MW) and molecular weight distribution (MWD) of each resin.

Suzy Monomer type (g) HCl (mmol) H ₂ O (mol) Resin yield (g) MW MWD (end) Monomer (A) 8.6 g Monomer (B) 10.9 g 6.1 0.3 8.8 5316 4.85 (I) Monomer (A) 8.6 g Monomer (C) 5.4 g 0.9 0.2 7.9 26778 7.46 (All) Monomer (A) 8.6 g Monomer (B) 10.9 g Monomer (C) 5.4 g 4.3 0.4 12.0 9904 6.30 (la) Monomer (D) 8.9 g Monomer (B) 10.9 g 0.6 0.3 17.2 3654 4.53 (hemp) Monomer (D) 8.9 g Monomer (C) 5.4 g 0.6 0.2 7.2 20452 8.70 (bar) Monomer (D) 8.9 g Monomer (B) 10.9 g Monomer (C) 5.4 g 5.4 0.5 13.2 10213 6.86

Note) Monomer (A): (t-butyl 5-norbornyl-2-carbonate) triethoxysilane (t-butyl 5-norbornyl-2-carbonate) triethoxysilane

Monomer (B): methyltriethoxysilane

Monomer (C): 1,2-bis (trimethoxysilyl) ethane (1,2-bis (trimethoxysilyl) ethane)

Monomer (D): (t-butyl 2-trifluoromethyl-3-propane) triethoxysilane (t-butyl 2-trifluoromethyl-3-propanate) triethoxysilane

Example 2: Formation of Low Dielectric Pattern Film

1 g of each of the siloxane resins (C) and (F) synthesized in Example 1 was dissolved in 8 g of propylene glycol methyl ether acetate with 0.02 g of triphenylsulfonium triflate, respectively. A resist solution was prepared. The resist solution was coated with a bare Si-wafer treated with HMDS (hexamethyldisilazane) to a thickness of about 0.3 μm, and then pre-dried at 120 ° C. for about 90 seconds, followed by ArF stepper (ASML, Netherlands) of ASML. It exposed at the exposure amount of 7.7 mJ / cm <^2> using 0.6NA and (sigma) 0.75).

Subsequently, PEB (post exposure baking) was performed at 120 ° C. for about 90 seconds, and then developed for about 60 seconds with a 2.38 wt% TMAH (tetramethylammonium hydroxide) solution. As a result, a clear 180 nm line and space pattern was formed.

The pattern film was then heat treated in a Linberg furnace to a final temperature described in Tables 2 and 3 in a vacuum atmosphere for 60 minutes to form nano pores. Same as 3.

Pattern film formed from resin (C) Heat treatment temperature (℃) 200 420 440 460 480 ¹⁾ refractive index 1.3821 1.3753 1.3691 1.3649 1.3622 ²⁾ Thickness 7905 7785 7681 7436 7756 ³⁾ permittivity 3.054 2.717 2.70 2.646 2.674

Pattern film formed from resin (bar) Heat treatment temperature (℃) 200 420 440 460 480 ¹⁾ refractive index 1.3852 1.3759 1.3704 1.36805 1.3558 ²⁾ Thickness 7864 7548 7649 7609 8036 ³⁾ permittivity 3.021 2.606 2.554 2.589 2.714

¹⁾ Measured using a prism coupler and an ellipsometer.

²⁾ prism coupler, ellipsometer and profiler

It was measured using a profilometer.

^{3) Using a} Hg CV meter (SSM 490i CV system, Solid State Measurements), the gate voltage was measured at -220 V to 220 V at a frequency of about 1 MHz. In calculating the permittivity, the capacitance of the control specimen coated with a thermally conductive silicon oxide (Thermal oxide) as a predetermined thickness as a reference material is measured, and the Hg electrode and the The contact area with the control specimens was obtained as the reference value:

A = C × t / k... … … … … (One)

Where

A = area of contact between Hg and the specimen

C = measured capacitance

t = thin film thickness on specimen

k = dielectric constant of the reference material (3.9 for thermal silicon oxide)

Since the thin film thickness on the specimen (hereinafter referred to as "converted thickness") is measured based on the capacitance of the test specimen and the reference value during the CV measurement, the converted thickness and the actual film thickness of the test specimen measured above are given by the following equation ( The permittivity of the test specimen was calculated by substituting 2):

k _{test specimen} = 3.9 × t _{test specimen} / t _thickness . … … … … (2)

As described in detail above, the siloxane-based resin of the present invention, which is an organic-inorganic composite matrix precursor containing both an unstable functional group and a thermally unstable functional group in an acidic atmosphere, has KrF (248 nm) and ArF (193 nm) in the presence of a photoacid generator. And a photoresist capable of forming a pattern of high resolution upon exposure with an F2 (157 nm) excimer laser, which is a next-generation energy exposure source. Finally, when the pattern thin film is heat-treated, very small pores of which size is 50 Å or less are extremely uniform. It is formed in a thin film with one distribution and has an extremely low dielectric constant (2.50 or less) which is useful as an interlayer insulating film of a semiconductor element. As described above, since the siloxane resin of the present invention serves as a low dielectric material and a photoresist, it is possible to simplify the process because there is no need to perform an interlayer insulating film forming process and a pattern forming process separately in manufacturing a semiconductor device. .

Claims (9)

(a) a silane compound having a structure of formula (1) and (b) a silane compound having a structure of formula (2) and / or (c) a silane compound having a structure of formula (3) in the presence of a catalyst and water in an organic solvent Siloxane Resin Prepared by Decomposition and Polycondensation: [Formula 1] SiR ₁ X ₁ X ₂ X ₃ Where R ₁ is a C ₅ to C ₁₀ alkylate group, cycloalkyate group or arylate group in which an acid and heat labile functional group is substituted; X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, an alkyl group of C _{1 to} C ₃ , an alkoxy group of C _{1 to} C ₄ , or a halogen group, At least two of them are C ₁ to C ₄ alkoxy groups or halogen groups; [Formula 2] SiR ₂ X ₁ X ₂ X ₃ Where R ₂ is a hydrogen atom, a C ₁ -C ₃ alkyl group, a C ₃ -C ₁₀ cycloalkyl group (cycloalky group) or an aryl group of C _{6 to} C ₁₅ ; X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, an alkyl group of C _{1 to} C ₃ , an alkoxy group of C _{1 to} C ₄ , or a halogen group, At least two of them are C ₁ to C ₄ alkoxy groups or halogen groups; [Formula 3] X ₃ X ₂ X ₁ Si- (R ₃ ) -SiX ₁ X ₂ X ₃ Where R ₃ is a C ₁ to C ₃ alkyl group or an oxyalkyl group, a C _{3 to} C ₁₀ cycloalky group or an oxycycloalkyl group group) or an aryl group or an oxyaryl group of C _{6 to} C ₁₅ ; X ₁ , X ₂ and X ₃ are each independently a hydrogen atom, an alkyl group of C _{1 to} C ₃ , an alkoxy group of C _{1 to} C ₄ , or a halogen group, at least one of which is an alkoxy group or halogen group of the C ₁ ~C _4. The siloxane-based resin according to claim 1, wherein the acid and heat labile functional group is selected from the group consisting of an ester group, a carbonate group, an acetal group, and a ketal group. According to claim 1, wherein the silane compound having a structure of formula (1) is (t-butyl 5-norbornyl-2-carbonate) triethoxysilane, (t-butyl 2-trifluoromethyl-3-propaneate ) Triethoxysilane, 4-methoxymethyloxy-4,4-ditrifluoromethyl-1-butyl) trimethoxysilane, and 4- (methoxymethyloxy-2- (1,3-ditri) Fluoromethyl) propyl) benzyl-1-ethyl) trimethoxysilane selected from the group consisting of siloxane resins. The silane compound of claim 1, wherein the silane compound having the structure of Chemical Formula 2 is methyltriethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, cyclohexyltriethoxysilane, trichlorosilane, trichlorosilylbuty Ronitrile, triethoxysilylethyl acetate, And triethoxy (3,3,3-trifluoropropyl) silane. The silane compound of claim 1, wherein the silane compound having the structure of Formula 3 is 1,2-bis (trimethoxysilyl) ethane, 1,4-bis (trimethoxysilyl) butane, 1,6-bis (trimethoxy) Oxysilyl) hex Acids, 1,4-bis (trimethoxysilyl) cyclohexane, 1,5-bis (trimethoxysilyl) -3-oxypentane, 1,4-bis (trimethoxyethylsilyl) benzene, and 1, A siloxane resin selected from the group consisting of 1'-bis (trimethoxyethylsilyl) benzyl ether. The method of claim 1, wherein in the case of performing binary copolymerization using two kinds of monomers, the molar ratio between the two monomers is (a) :( b) (or (c)) = 0.1 to 99.9: 99.9 to 0.1 Siloxane-based resin. The method of claim 1, wherein in the case of terpolymer copolymerization using three kinds of monomers, the molar ratio between the three monomers is (a) :( b) :( c) = 0.1-99.9: 0.1-99.9: 0.1-99.9. A siloxane resin characterized by the above-mentioned. A method of forming a low dielectric pattern film comprising the following steps: Dissolving the siloxane resin of claim 1 in an organic solvent together with a photoacid generator to provide a coating solution; Applying the coating solution on a silicon substrate and then pre-baking to deposit a resin film on the substrate; Exposing the resin film through a photomask and then drying the post-exposure baking; Developing the resin film to express a pattern; And Heat-treating the pattern. The method according to claim 8, wherein the coating solution is prepared by dissolving 100 parts by weight of the siloxane resin and 1 to 10 parts by weight of the photoacid generator so as to have a solid concentration of 0.1 to 80% by weight in an organic solvent.