KR100595527B1 - Ultra-low Dielectrics Prepared by Oligomer Derivatives of monosaccharides for Cupper Interconnect - Google Patents

Abstract

The present invention relates to an ultra low dielectric film for copper wiring using an oligomeric derivative of a monosaccharide, and more particularly, to a monosaccharide oligomer derivative having a novel structure prepared by sol-gel reaction of a monosaccharide derivative having an alkoxysilane end group, and an oligomer of the above monosaccharide. It is prepared by thinning the ultra-low dielectric composition containing a derivative and then curing and high temperature heat treatment, and relates to an ultra-low dielectric film having a very low dielectric constant, excellent mechanical strength, and very small nanopores of 2 nm or less.

Monosaccharide Derivatives, Monosaccharide Oligomer Derivatives, Sol-Gel Reaction, Ultra Low Dielectric Membrane, Pore Forming Template, Permittivity, Mechanical Properties, Nanopore

Description

Ultra-low Dielectrics Prepared by Oligomer Derivatives of monosaccharides for Cupper Interconnect}             

1 is a ¹ H-NMR spectrum of a monosaccharide derivative having a ethoxysilane end group (TESGC).

Figure 2 is a graph showing the change in refractive index according to the content of the oligomeric derivative (THSGC) of the monosaccharide.

3 is a graph showing the porosity change according to the content of the oligomeric derivative (THSGC) of the monosaccharide.

4 is a graph showing the change in permittivity according to the content of the oligomeric derivative (THSGC) of the monosaccharide.

The present invention relates to an ultra low dielectric film for copper wiring using an oligomeric derivative of a monosaccharide, and more particularly, to a monosaccharide oligomer derivative having a novel structure prepared by sol-gel reaction of a monosaccharide derivative having an alkoxysilane end group represented by the following formula (1): In addition, the ultra-low dielectric composition containing the oligomeric derivatives of the above monosaccharides was prepared by thinning and curing and high temperature heat treatment. The ultra-low dielectric film containing very small nanoporosity of less than 2 nm with low dielectric constant and excellent mechanical strength It is about.

In Formula 1, R is the same as or different from each other and represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, n is an integer of 2 to 6, m is an integer of 1 to 3.

As the demand for higher integration and higher speed of next-generation semiconductor devices is required, the minimum line width of integrated circuits is rapidly decreasing, and advanced semiconductor manufacturers including Intel Corporation (Intel C0.) Already have copper having a minimum line width of 65 nm or 70 nm in 2003. We have developed a semiconductor process for wiring. This new process technology consists of eight layers of copper wiring, which not only improves the signal speed of the chip itself, but also lowers power consumption with various functions, but has a very low dielectric constant ( k ) of about 2.0 to 2.2. Therefore, the present invention is not applicable to commercially available low-k materials ( k to 2.7).

Currently, as a method for manufacturing a low dielectric film required as a low dielectric material around the world, a method of introducing a large amount of pores into a dielectric film has been developed ( k to 1.0), wherein the size of pores generated in the dielectric film is about 4 They are trying to create a closed structure that is very small and even below nm and at the same time the pores are not connected to each other. Currently, the most advanced technology in this field has been developed by IBM, which combines organic-inorganic nanoparticles using a thermally labile organic poregen as a template, blending with an inorganic low dielectric matrix and using phase separation that occurs during the curing process. The nanoporous ultra low dielectric film is obtained by preparing a hybrid and then heat treating at a high temperature.

Representative organic poregens currently developed include hyperbranched polyesters [C. Nguyen, CJ Hawker, RD Miller and JL Hedrick, Macromolecules , 33 , 4281 (2000)], ethylene-propylene-ethylene triblock copolymers (pluonics ™) [S. Yang, PA Mirau, EK Lin, HJ Lee and DW Gidley, C hem. Mater ., 13 , 2762 (2001)], polymethylmethacrylate- N, N -dimethylaminoethyl methacrylate copolymer [QR Huang, W. Volksen, E. Huang, M. Toney and RD Miller, C hem. Mater ., 14 (9), 3676 (2002). However, when the above-mentioned materials are used as the pore-forming agent, the phase-separated organic pore-forming agent does not have a spherical shape but has a long elongated form, and when the porosity is about 15%, an open pore structure is generated, thereby causing the mechanical properties of the porous thin film. The problem occurs that the strength is significantly reduced. Therefore, in order to manufacture an ultra low dielectric film having excellent mechanical strength and low dielectric constant, it is important to minimize phase separation of the pore-forming agent occurring during the curing process of the matrix, and to reduce the decrease in mechanical strength according to the pore content. It is urgent to develop a new concept of pore forming agent.

In this regard, the present inventors use an oligomeric organic silicate precursor prepared through a sol-gel reaction using a cyclodextrin having an alkoxysilane end group as a basic monomer as a pore-forming template, which has a low dielectric constant and excellent mechanical strength. It has been developed a technology for producing an ultra low dielectric film having a [Korean Patent Application No. 2004-10827].

The present invention was obtained by the inventors of the present inventors' continuous study on the production of ultra-low dielectric films containing nanopores having a very low dielectric constant and excellent mechanical strength, and the oligomeric derivative is obtained by sol-gel reaction of the monosaccharide derivative represented by Chemical Formula 1 Synthetic oligomeric derivatives of the monosaccharides synthesized have alkoxysilyl groups at their ends, and thus have been found to be useful as templates for forming pores for the preparation of ultra-low dielectric films.

Therefore, an object of the present invention is to provide a use of the oligomeric derivative of the monosaccharide represented by the formula (1) as a template for pore formation.

Another object of the present invention is to provide an ultra low dielectric composition containing an oligomeric derivative of the monosaccharide represented by the formula (1).                         

In addition, the present invention is another object of the present invention to provide an ultra-low dielectric film prepared by coating the ultra-low dielectric composition on the substrate to the sol-gel reaction and high temperature heat treatment.

The present invention is characterized by an oligomeric derivative of the monosaccharide represented by the following formula (1) useful as a pore-forming template, an ultra low dielectric composition containing the above oligomer, and an ultra low dielectric film prepared from the composition.

[Formula 1]

In Formula 1, R is the same as or different from each other and represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, n is an integer of 2 to 6, m is an integer of 1 to 3.

Referring to the present invention in more detail as follows.

The oligomer according to the present invention is a novel substance prepared by sol-gel reaction of the monosaccharide derivative represented by Chemical Formula 1, and is an oligomeric polymer having a molecular weight range of 8,000 to 50,000.

In addition, the monosaccharide derivative represented by the formula (1) used in the oligomer synthesis of the present invention is also a novel compound, the monosaccharide derivative represented by the formula (1) is a series of allylation and hydrosilylation reaction of the hydroxyl group portion of the monosaccharide Compound prepared by the following. As the monosaccharide, any applicable 5- to 8-membered cyclic sugar compound having a hydroxy group bonded thereto may be applied, and among these, a monosaccharide of pentose or hexasaccharide is preferably used. Ribose, D-Arabinose D-Xylose, D-Lyxose, D-Allose, D-Altrose, D-Glucose , D-mannose, D-gulose, D-idose, D-galactose, D-talose, and the like. In the above allylation reaction, a monosaccharide derivative containing an alkenyl group is prepared by dissolving a monosaccharide in an organic solvent, inducing dehydrogenation using NaH, and then adding and reacting an alkenyl compound such as an alkenyl halide. In this case, the alkenyl compound is preferably a compound having 1 to 6 carbon atoms, specifically, vinyl halide, allyl halide, 1-butenyl halide, 1-pentenyl halide, 1-hexenyl halide may be included. have. In addition, the hydrosilylation reaction is performed by the reaction of the alkynyl group and the alkenyl group introduced into the monosaccharide under the platinum catalyst, thereby preparing a monosaccharide derivative containing an alkoxysilane end group represented by the formula (1).

The monosaccharide derivative represented by Chemical Formula 1 has a structure including an alkoxysilane group at a 5- to 8-membered ring terminal, thereby forming an oligomeric organic silicate precursor by a sol-gel reaction in itself. In the sol-gel reaction, the monosaccharide derivative represented by Chemical Formula 1 is dissolved in an organic solvent such as tetrahydrofuran (THF) at a concentration of 3 to 20% by weight, and a small amount of water and HCl catalyst are added dropwise thereto and then -20 to It is carried out at 20 ° C. for about 2 to 4 hours. When the sol-gel reaction is completed, diethyl ether and water are added to the reaction solution, mixed, and then distilled to remove the solvent, thereby obtaining an oligomeric derivative of a monosaccharide. The oligomers prepared by this method range in molecular weight from 8,000 to 50,000.

On the other hand, the oligomeric derivative of the monosaccharide according to the present invention can be contained in a conventional dielectric composition to prepare an ultra low dielectric film. In more detail, the ultra-low dielectric film may be prepared by containing 10 to 90% by volume of the oligomer as a pore forming template in 10 to 90% by volume of a conventional organic or inorganic silicate precursor used as a low dielectric matrix. In addition, the oligomer is capable of curing by polymerization and sol-gel reaction, and thus may serve as a matrix as it is. Thus, even if it does not contain a conventional organic or inorganic silicate precursor as a matrix component, An ultra low dielectric film can also be prepared by containing the oligomer as a template.

The organic or inorganic silicate precursor which may be contained in the ultra low dielectric composition of the present invention may be applied to any organic or inorganic silicate precursor that has been generally used as a low dielectric matrix, and particularly has a higher porosity than when using a precursor having a high silanol content. And dielectric properties. Particularly preferred among conventional low dielectric matrices is the use of polymethylsilsesquioxane homopolymers or copolymers.

Meanwhile, in order to manufacture an ultra low dielectric film using the ultra low dielectric composition described above, a conventional low dielectric film manufacturing method, for example, spin coating on a substrate and thinning the film, performs curing and high temperature heat treatment. More specifically, the solution obtained by dissolving the matrix component and the pore-forming template component in an organic solvent at a concentration of 10 to 80% by weight is dropped onto the substrate, followed by 20 to 70 seconds at 2000 to 4000 rpm. A thin film is prepared by spin coating. At this time, the organic solvent may include normal butanol, normal butyl acetate, dimethylformamide (DMF), dimethyl acrylamide (DMA), dimethyl sulfoxide (DMSO). As a board | substrate, the conventionally used conventional thing is used, Preferably the silicon wafer prepared by passing through the polytetrafluoroethylene syringe filter (0.2 micrometer) is used. Then, the prepared thin film is heated to 200-300 ° C. to remove residual solvent and condensation reaction of silanol end groups of the matrix, and then maintained at 350-500 ° C. for 1 hour to remove organic material, thereby removing nanopores. An ultra low dielectric thin film is prepared. The curing reaction and organic material removal were carried out in a nitrogen atmosphere, the temperature rising and falling rates were set to 3 ℃ / min, respectively.

In the ultra-low dielectric film of the present invention prepared by the above manufacturing method, pores of 2 nm or less are uniformly distributed. In addition, the ultra-low dielectric film of the present invention has a low dielectric constant of about 2.2 to 2.0.

Such a present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

Synthesis Example 1 Synthesis of Glucose Compound (TESGC) Containing Ethoxysilane End Group

After dissolving 5.24 g of glucose in 20 mL of dimethylformamide (DMF) and injecting it slowly into a NaH-dissolved DMF solution to induce dehydrogenation, 21 mL of allyl bromide was added dropwise to proceed. Glucose containing allyl groups was prepared by removing the solvent and excess allylbromide. Thus prepared glucose containing allyl group was dissolved in 1.8 g of triethoxysilane, and the reaction was carried out by adding an appropriate amount of platinum oxide (PtO ₂ ) catalyst, and finally removing the solvent and catalyst to have an ethoxysilane end group. Glucose compound (TESGC) was prepared.

In addition, ¹ H-NMR spectrum of a glucose compound (TESGC) having an ethoxysilane end group prepared by the method of Synthesis Example 1 was attached to FIG. 1.

Synthesis Example 2 Synthesis of Monosaccharide Oligomer Derivative (THSGC)

To 20 mL of a solution in which the monosaccharide derivative prepared in Synthesis Example 1 was dissolved in tetrahydrolufuran (THF) at a concentration of 5% by weight, 0.1 mL of water and 0.05 mL of 35% HCl solution were added dropwise, and about 2 at 0 ° C. The sol-gel reaction was carried out for a time. After the reaction, an excess of potassium carbonate (K ₂ CO ₃ ) was added to remove the HCl catalyst, followed by distillation under reduced pressure and vacuum drying to prepare an organic silicate precursor (THSGC) in oligomeric form.

EXAMPLES Preparation of Ultra-Low Dielectric Film Containing Nanopores

Example 1:

As the matrix component, a polymethylsilsesquioxane copolymer (BTESE 50%, Korean Patent Publication No. 2002-38540) in which methyltrimethoxysilane and α, ω-bistriethoxysilylethane were copolymerized in a 5: 5 molar ratio was used. As the pore forming template, an ultra low dielectric film was prepared using the oligomer (THSGC) prepared in Synthesis Example 2.

Each of the matrix component and the pore-forming template prepared a 30 wt% concentration solution using n-butanol / n-pentanol mixed solvent (1/1, v / v). Each of the prepared matrix solution and the template solution were mixed and then passed through a polytetrafluorine (PTFE) syringe filter (0.2 μm) to prepare a superelectric composition.

After dropping a few drops of the above superelectric composition on a silicon wafer substrate, a thin film was prepared by spin coating at 3500 rpm for 50 seconds. The thin film thus prepared was heated to 250 ° C. to induce solvent removal and condensation reaction of the inorganic matrix, and then heat treated at 430 ° C. for one hour to finally prepare an ultra low dielectric film containing nanopores. The curing reaction and organic material removal were carried out under a nitrogen atmosphere, and the temperature rising and falling rates were 3 ° C./min, respectively.

Example 2:

An ultra low dielectric film was prepared using the oligomer (THSGC) prepared in Synthesis Example 2 as a matrix and a pore forming template.

That is, the oligomer (THSGC) prepared in Synthesis Example 2 was used to prepare a 30 wt% concentration solution using n-butanol / n-pentanol mixed solvent (1/1, v / v). And, in the same manner as in Example 1, spin coating and high temperature heat treatment were performed to prepare silicate ultra low dielectric films containing nanopores.

The ultra-low dielectric films prepared in Examples 1 and 2 were measured by the method of the following test example, the results are shown in Table 1 and Figures 2 to 4, respectively.

Experimental Example: Measurement of Properties of Thin Films

The refractive index and thickness of the thin film were measured at 632.8 nm wavelength using an ellipsometer (Elpsometer, L166C, Gaertner Scientific Corp.).

The porosity of the thin film was calculated using the Lorentz-Lorentz equation represented by Equation 1 below.

In Equation 1, n _s or n _r represents the refractive indices of the porous or nonporous film, respectively, and p represents the porosity.

The dielectric constant of the thin film was measured in the following manner. A very high conductivity silicon wafer (0.008 Ω · m) was used as the lower electrode, an ultra low dielectric thin film thereon, and an aluminum electrode having a diameter of about 1 mm thereon was again vacuum deposited to prepare an upper electrode. Thus prepared specimens were measured for capacitance at 1 MHz using an HP 4194A impedance analyzer, and then the dielectric constant was calculated in consideration of known thin film thickness and electrode area. In addition, the theoretical dielectric constant was calculated using the Maxwell-Garnett equation represented by the following equation (2).

In Equation 2, k _s or k _r represents the dielectric constants of the porous or nonporous film, respectively, and p represents the porosity.

Ultra low dielectric film matrix Template (% by volume) Refractive Index (R.I.) Porosity (%) Dielectric constant ( k ) Estimates Measure Example 1 BTESE 50% THSGC 0 1.420 0.0 - 3.0 40 1.340 15.5 2.46 2.50 60 1.289 26.5 2.16 2.18 Example 2 THSGC 1.321 2.40  BTESE 50%: polymethylsilsesquioxane copolymer THSGC: oligomer prepared by sol-gel reaction of a monosaccharide derivative represented by Formula 1 having a triethoxysilane end group

As described above, the dielectric film prepared by including the oligomeric derivative of the monosaccharide according to the present invention has a low dielectric constant, excellent mechanical strength, and has a very small pore size of 2 nm or less. useful.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of the present invention will be apparent from the appended claims.

Claims (6)

A low dielectric matrix and pore-forming template, which is an oligomer prepared by sol-gel reaction of a monosaccharide derivative having an alkoxysilane end group represented by the following formula (1): [Formula 1]

In Formula 1, R is the same as or different from each other and represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, n is an integer of 2 to 6, m is an integer of 1 to 3. In a low dielectric composition containing a matrix and a template for pore forming, Ultra low dielectric composition, characterized in that the oligomer of claim 1 is contained as the matrix and pore forming template. Ultra low dielectric film, characterized in that prepared using the composition of claim 2. In a low dielectric composition containing a matrix and a template for pore forming, a) 10 to 90% by volume of the organic or inorganic silicate precursor as the matrix, b) 10 to 90% by volume of the oligomer of claim 1 Ultra low dielectric composition, characterized in that it contains. The ultra low dielectric composition according to claim 4, wherein the matrix is a polymethylsilsesquioxane homopolymer or copolymer. Ultra low dielectric film, characterized in that prepared using the composition of claim 4.

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