WO2019168288A1

WO2019168288A1 - Insulation film formation method and insulation film producing apparatus

Info

Publication number: WO2019168288A1
Application number: PCT/KR2019/001869
Authority: WO
Inventors: 최영준; 정진국; 신경득; 이상욱
Original assignee: 최영준
Priority date: 2018-02-28
Filing date: 2019-02-15
Publication date: 2019-09-06

Abstract

The present invention relates to an insulation film formation method in which a material constituting an insulation film is nano-fiberized by electrospinning to obtain an insulation film formed of nanofiber clusters, an insulation film obtained thereby, and an insulation film producing apparatus, An insulation film formation method according to the present invention comprises: (1) a preparation step of mounting a wafer on a collection part and supplying a film forming material to be formed as a nanofiber to a spinning nozzle by using an electrospinning device including a high voltage generation device, the spinning nozzle, and the collection part, the spinning nozzle being electrically connected to one electrode of the high voltage generation device, the collection part being electrically connected to the other electrode (counter electrode) of the high voltage generation device; and (2) a lamination step of operating the high voltage generation device to electrospin the film forming material from the spinning nozzle so as to form, on the wafer, a layer formed of clusters of a nanofiber of the film forming material, which is formed by electrospinning.

Description

Insulating film forming method and insulating film manufacturing apparatus

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating film forming method and an insulating film manufacturing apparatus, and more particularly, to an insulating film forming method and an insulating film manufacturing apparatus in which a material constituting the insulating film is formed into nanofiber clusters by nanofiberization by electrospinning.

The present invention is generally widely applicable to the manufacture of electronic device materials such as semiconductors, semiconductor devices, liquid crystal devices, and the like. Here, for convenience of description, the background art of semiconductor devices will be described as an example.

Thinner wire thickness and narrower wiring spacing due to the reduction of integrated circuits (IC) offsets the speed-up benefits that can be achieved by reducing the size of the device due to increased resistance and resistance-capacitance (RC) coupling problems. . Methods for improving semiconductor device performance and reliability include using high conductive materials (metals) such as copper and using low-k materials.

Substrates for semiconductor to electronic device materials including silicon are subjected to various processes such as formation of insulating films including oxide films, film formation by CVD, and the like.

It is no exaggeration to say that the recent high performance of semiconductor devices has developed on the miniaturization technology of such devices including transistors. To this day, further refinement of transistor miniaturization technology has been achieved with the aim of further improving the performance. With the recent demand for miniaturization and high performance of semiconductor devices (for example, in view of leakage current), the need for higher performance insulating films has increased significantly. This is because even a leakage current that is not a problem in the conventional relatively low integration device may cause serious problems in recent miniaturization, high integration, and / or high performance devices. Typically, in developing next-generation MOS transistors, for example, as the above-described miniaturization technique progresses, thinning of the gate insulating film is approaching a limit, and a great problem to be overcome is raised. That is, as the process technology, it is possible to thin the silicon oxide film (SiO ₂ ), which is currently used as the gate insulating film, to an extreme (1 to 2 atomic layer level), but when thinning to a film thickness of 2 nm or less, The direct tunnel causes an exponential increase in leakage current, resulting in an increase in power consumption.

Typically, for example, in developing next-generation MOS transistors, the pursuit of miniaturization of high-performance silicon LSI causes a problem that leakage current increases and power consumption increases. Therefore, in order to reduce the power consumption while pursuing performance, it is necessary to improve the characteristics of the transistor without increasing the gate leakage current of the MOS transistor.

Low dielectric constant materials are semiconductor insulating materials having a dielectric constant lower than the dielectric constant of silicon dioxide (SiO ₂ ) 3.9 to 4.2. As more advanced technology is needed, ultra low dielectric constant (ULK) dielectric materials with dielectric constants lower than 2.0 are required.

ULK dielectrics can be obtained by creating a porous dielectric comprising pores in a low-k dielectric material. Applications of ULK dielectrics include interlayer insulators (ILDs) and intermetallic insulators (IMDs).

Various semiconductor materials and equipment development companies are continuously conducting research on CVD (chemical vapor deposition) and spin-on deposition (SOD) thin film process technology, and the results of the research are reported. Until now, the research of low dielectric films has been selected for OSG (organosilicate glass) materials using PECVD in consideration of product stability while meeting the demands of the market. However, OSG materials for PECVD currently remain at κ> 2.4. More than 40% porosity is required in the low dielectric material to achieve κ <2.2 required in processes below 40 nm. However, in the case of PECVD, there is a limit in introducing more than 40% of pores while maintaining good mechanical properties, so it is difficult to lower the dielectric constant any more. In order for the spin-on ultra low dielectric constant materials to be applied as an interlayer insulating material, it is possible to realize a small, closed pore morphology (i.e., mesoporous) with excellent physical properties and matrix polymer with high physical properties. Pore former development and pore formation research must all be successful, which is a very important task to determine the limits of next-generation memory and non-memory semiconductor performance.

A new concept of pore generation, called Moleclular-Pore-Stacking (MPS), has been used to report the successful development of materials and processes of κ = 2.4 for 45 nm-node LSI, and porous organosilicates. Research on the LKD series, a kind of porous organosilicate, is ongoing, and there are comments on the progress of research on ULK dielectrics with a dielectric constant of 2.2 or less, CVD low-k, and low pattern-capable low-k.

The development of CVD porous low-k dielectric film is currently reported to κ = 2.2 to 2.5, and most of spin-on materials are organic polymers such as polyimide, polyarylene ether (PAE), cyclobutane derivatives and aromatic thermosetting polymers. It concentrates on organosilicate materials that can achieve a series or organic-inorganic hybrid effect.

When pores are introduced into the organic silicate thin film having a dielectric constant of 2.7 to 3.0, the dielectric constant of air is 1, and thus the dielectric constant is lowered, and as more pores are introduced, the pores are lowered as shown in FIG. 1.

In addition, the low dielectric constant porous insulating layer preferably satisfies the following characteristics:

Low dielectric constant

Thermally stable at temperature> 450 ° C for some hours

Excellent adhesion to underlying and top layers

Resisting to solvents and resists used in lithography

Patterning (etch in RIE)

Flatness (self-planarization or planarization with CMP)

Low water absorption

Low and isotropic coefficient of thermal expansion (CTE)

Acceptable dielectric loss, breakdown voltage, and leakage current

Excellent gap-fill properties

High mechanical strength

High glass transition temperature

High thermal conductivity.

In order to attain both such miniaturization and improvement of properties, an insulating film is indispensable to be of good quality and thin (for example, about 15 GPa or less in thickness). However, formation of a high quality thin insulating film is very difficult. For example, when such an insulating film is formed by conventional thermal oxidation method or CVD (chemical vapor deposition method), the characteristics of either film quality or film thickness are insufficient.

The insulating film can be manufactured by plasma CVD (chemical vapor growth method), but it is difficult to obtain satisfactory interface characteristics. In this case, the most important problem is that ion damage by plasma cannot be avoided.

On the other hand, TFTs (thin film transistors) with higher densities are required to develop large-sized, high-precision and highly functional liquid crystal displays. There is a growing need for TFTs of polysilicon (poly-Si) films instead of ordinary amorphous silicon film TFTs. A gate insulating film important for the performance and reliability of the TFT is provided by plasma CVD. However, if the gate insulating film is formed using plasma CVD, damage by plasma is inevitable. In this case, in particular, since the threshold voltage of the generated transistor cannot be controlled with high precision, the reliability of the transistor can be lowered.

In the case of poly-Si TFTs, it is common to form SiO ₂ films by plasma CVD using TEOS (tetra ethyl ortho silicate) and O ₂ gas. Such SiO ₂ films contain the carbon atoms originally contained in the gaseous material. Even if the film is formed at 350 ° C. or higher, it is difficult to reduce the carbon concentration to 1.1 × 10 ²⁰ atoms / cm 3 or less. In particular, when the film formation temperature is as low as about 200 ° C., the carbon concentration in the film can be increased to a size of up to 1.1 × 10 ²¹ atoms / cm 3. Therefore, it is difficult to lower the film forming temperature.

In the case of plasma CVD using SiH ₄ and N ₂ O-based gases, the interfacial stationary charge density cannot be less than 5 × 10 ¹¹ cm ⁻² , because the interfacial nitrogen concentration is larger than 1 atomic%. It is not possible to obtain a functional gate insulating film.

Oxidation methods such as, for example, ECR plasma CVD and oxygen plasma have been developed to reduce ion damage by plasma CVD to obtain high quality insulating films. However, since plasma occurs near the surface of the semiconductor, it is difficult to completely avoid ion damage.

For example, cleaning devices using light sources such as low pressure mercury lamps and excimer lamps have already been used for mass production.

A method of using light to oxidize silicon at low temperatures of 250 ° C. has been studied. In this method, however, the film formation rate is as low as 0.3 nm / minute. At present, it is difficult to actually form the entire gate insulating film (see J. Zhang, A.P. L., 71 (20), 1997, P2964).

JP-A 4-326731 discloses an oxidation method carried out in an ozone-containing atmosphere. However, as described above, in this method, ozone is generated using light and ozone is decomposed using light to generate oxygen atom radicals. That is, the method comprises two reaction steps. Therefore, the method is not effective and the oxidation rate is low.

As described above, in the case of deposition (plasma CVD, etc.), a thick insulating film can be formed quickly on the semiconductor, but since the surface of the original semiconductor remains as an interface between the semiconductor and the insulating film (gate insulating film), ion damage can be avoided. none. Therefore, since the interface level density rises, satisfactory device characteristics cannot be obtained.

When an insulating film is formed on a semiconductor using an oxidation method (for example, an oxygen plasma oxidation method), the oxidation reaction proceeds from the surface of the semiconductor to the inside, and the interface between the semiconductor layer (semiconductor) and the insulating film is originally formed inside the semiconductor layer. . Therefore, since this interface is substantially unaffected by the original surface conditions, there is an advantage that a very satisfactory interface can be obtained. However, high temperature processes can warp the silicon wafer. Low temperature suppresses warpage but reduces the oxidation rate. Therefore, the low temperature process cannot produce the insulating film at a substantial speed.

Korean Patent No. 10-0481835 (name of the invention: a method for forming an insulating film, a semiconductor device and a manufacturing device) includes a step of forming a first insulating film by oxidizing a surface of a semiconductor in an atmosphere containing oxygen atom radicals, and A method of forming an insulating film at a semiconductor temperature of 600 ° C. is disclosed, which includes forming a second insulating film on the first insulating film by deposition without exposing the first insulating film to the atmosphere, but using a plasma CVD method. will be.

Korean Patent No. 10-0782954 (name of the invention: a method for forming an insulating film) includes a step of forming an insulating film on a substrate for an electronic device, wherein two or more steps for controlling the insulating film properties included in the step are performed under the same operating principle. The insulating film on the surface of the substrate is formed. By avoiding exposure to the atmosphere and performing cleaning, oxidation, nitriding, thinning, and the like, an insulating film having a high degree of cleaning can be formed. In addition, it has been disclosed that by implementing various processes related to the formation of the insulating film by using the same operating principle, it is possible to realize the simplification of the device shape and to efficiently form the insulating film having excellent characteristics, but this also uses the plasma CVD method. will be.

In Korean Patent Publication No. 10-2008-0007192 (name of the invention: low temperature sol-gel silicate as dielectric or planarization layer for thin film transistors), the inventors have found that the inventors cure at 135 ° C to 250 ° C even though the process temperature is reduced. It has been found that films can be made from certain combinations of sol-gel silicate precursors that also provide good leakage current density values (9 × 10 ⁻⁹ A / cm 2 to 1 × 10 ⁻¹⁰ A / cm 2). There are some first examples of silicates, where the silicates are cured at low temperatures and the leakage current density is low enough to be used as a low temperature treated, solution treatable or printable dielectric, which dielectrics are for flexible or light weight thin film transistors. Used. These formulations disclose that they can also be used in the planarization of stainless steel foils used for thin film transistors and other electronic devices. This uses the sol-gel method.

In addition, porogen having a modified end group silyl as for the existing low dielectric porous semiconductor insulating film formation; Thermally stable organic or inorganic matrix precursors; And a technique using a composition for forming a material having nano-pores, including a solvent for dissolving the material has been proposed, which is sufficient to remove the porogen before the heat treatment for the stability of the film formation contributes to the decrease in the dielectric constant in the void A heat treatment process above the boiling point of porogen to form pores should be added.

SUMMARY OF THE INVENTION The present invention provides a method for forming an insulating film having nanoporous fibers formed by nanospinning a material constituting the insulating film by electrospinning to form a nanofiber cluster and having fibrous pores from the film forming step, and an insulating film and insulating film manufacturing apparatus obtained therefrom. There is this.

The insulating film forming method of the present invention includes (1) a high voltage generator, a radiation nozzle electrically connected to one electrode of the high voltage generator, and a collecting part electrically connected to the other electrode (large electrode) of the high voltage generator. Supplying a deposition material to be formed of nanofibers to the spinning nozzle using an electrospinning device, and preparing a wafer in a collecting unit; And (2) a laminating step of operating the high voltage generator to electrospin the film forming material from the spinning nozzle to form a layer consisting of clusters of nanofibers of the film forming material formed by electrospinning on the wafer. do.

The insulation film manufacturing apparatus of the present invention includes a high voltage generator, a radiation nozzle electrically connected to one electrode of the high voltage generator, and a collector electrically connected to the other electrode (large electrode) of the high voltage generator. In the collection portion is characterized in that it further comprises a fixing means for fixing the wafer.

According to the present invention, there is an effect of providing a method for forming a porous insulating film in which the material constituting the insulating film is nanofiberized by electrospinning to form a nanofiber cluster, and the insulating film and insulating film manufacturing apparatus obtained therefrom.

1 is a graph showing the porosity, that is, the relationship between porosity and relative dielectric constant. A graph showing a decrease in permittivity according to pores in a material having a certain dielectric constant is given to a material having a dielectric constant (k) of 2.8 or more with a porosity of 40% or more. It is shown schematically that it can have a dielectric constant of 2.0 or less, which is advantageous for forming ultrafast semiconductors.

Figure 2 is a schematic diagram showing one specific example of the electrospinning apparatus that can be used in the present invention.

Figure 3 is a schematic diagram showing another embodiment of the electrospinning apparatus that can be used in the present invention.

4 is a diagram schematically illustrating the concept of a technical configuration in which an insulating layer made of nanofiber clusters is formed by an electrospinning apparatus according to the present invention.

5 is a surface photograph of a polyimide film obtained according to one embodiment of the present invention.

6 is a cross-sectional photograph of the polyimide film of FIG. 5.

The present invention, in its best form, includes (1) a high voltage generator, a radiation nozzle electrically connected to one electrode of the high voltage generator and a collector electrically connected to the other electrode (the counter electrode) of the high voltage generator. Supplying a deposition material to be formed of nanofibers to the spinning nozzle using an electrospinning device, and preparing a wafer in a collecting unit; And (2) a laminating step of operating the high voltage generator to electrospin the film forming material from the spinning nozzle to form a layer of clusters of nanofibers of film forming material formed by electrospinning on the wafer; It provides a method for forming an insulating film comprising a.

Also, a high voltage generator, a radiation nozzle electrically connected to one electrode of the high voltage generator, and a collector electrically connected to the other electrode (the counter electrode) of the high voltage generator, wherein the collector includes a wafer. The present invention provides an insulating film manufacturing apparatus further comprising a fixing means for fixing.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The polymer material has an advantage that it can be easily processed into a planar, fibrous or molded shape depending on the processing method. In processing into a fibrous shape, the thickness and the shape of the cross section can be adjusted according to the diameter or shape of the spinning nozzle.

In the present invention, a porous film having a hollow space such as a net membrane having a three-dimensional structure by coating a fibrous material on a semiconductor wafer by electrospinning a film-forming material suitable for use as an insulating film for a semiconductor process among polymer materials as a solution or a molten phase. It is an object of the present invention to provide an insulating film (Mesoporous Dielectric Insulating layer).

In the mechanical spinning method, which physically processes the diameter of the spinning nozzle by several nano units to form a single nanofiber shape, it is not only possible to apply a wide semiconductor wafer between patterns in a short process time, but also to form a network structure. Therefore, the present invention is based on the electrospinning technology that is spun off into numerous nanofibers by applying high voltage to the liquid organic polymer or inorganic material sprayed through the spinning nozzle as the background of the technology, and the method and apparatus as appropriate for the semiconductor process. It characterized in that to apply a strain.

The present invention proposes a method and apparatus for allowing nanofibers from one or more spinning nozzles to cover the wafer surface with a three-dimensional mesh structure on the wafer surface by configuring the wafer surface to perform the role of a collector.

The present invention provides an insulating film for a semiconductor process having excellent insulating properties by using an electrospinning method of nanofiberization at high voltage when spraying a polymer or inorganic material through a spinning nozzle in a liquid phase, and is not limited to the insulating film and applied to other thin film forming processes. can do.

The preparation step of (1) includes a high voltage generator, a radiation nozzle electrically connected to one electrode of the high voltage generator, and an electrospinning unit including a collector electrically connected to the other electrode (large electrode) of the high voltage generator. The apparatus consists of supplying a film forming material to be formed of nanofibers to a spinning nozzle and mounting a wafer on a collecting part. The deposition material to be supplied to the spinning nozzle to be electrospun may be formed into nanofibers by being supplied in the fluid phase, i.e., in the liquid phase, and spun by a high voltage applied by the high voltage generator in a subsequent lamination step. To this end, one electrode of the high-voltage generator of the electrospinning apparatus is electrically connected to the radiation nozzle, the other electrode (the counter electrode) is connected to the collector, and the cluster of nanofibers made of a film-forming material is stacked on the collector. Therefore, due to the structure of the nanofibers constituting the layer, a plurality of pores are formed between the fibers to have a porous structure.

The laminating step of (2) is performed by operating the high voltage generator to electrospin the film forming material from the spinning nozzle to form a layer consisting of clusters of nanofibers of film forming material formed by electrospinning on the wafer.

After the lamination step of (2), the wafer on which the layer formed of the nanofibers of the film forming material formed by electrospinning is formed is above the boiling point of the solvent or below the melting point of the film forming material, for example, the largest heat resistance known as the film forming material. The polymer may further include a first heat treatment step of heat treatment for 10 minutes to 1 hour at the melting point limit of 450 ℃. If the heat treatment temperature in the first heat treatment step is heat-treated below the boiling point of the solvent or less than 10 minutes, insufficient solution removal and partial closing of the pores occur in the case of the solution, so that the required film quality of the insulating film or other semiconductor structure is insufficient. There may be a problem that affects the properties, on the contrary there may be a problem that can not maintain the pore structure or cause unnecessary process time if the heat treatment above the melting point of the applied deposition material or more than 1 hour.

After the lamination step (2) and / or after the first heat treatment step, the wafer on which the layer formed of the nanofibers of the film-forming material formed by electrospinning and / or the first heat-treated wafer is in an inert atmosphere, preferably The method may further include a second heat treatment step of performing heat treatment for 10 minutes to 2 hours at or above the boiling point of the solvent or below the melting point of the deposition material under a nitrogen atmosphere. If the heat treatment in the second heat treatment step exceeds 2 hours, there may be a problem that causes unnecessary process time.

As shown in FIGS. 2 and 3, the insulating film manufacturing apparatus of the present invention includes a radiation nozzle 12 and a high voltage generator electrically connected to one electrode of the high voltage generator 11, the high voltage generator 11. And a collecting part electrically connected to the other electrode (the counter electrode), wherein the collecting part further includes fixing means for fixing the wafer 13. That is, the device is configured to spray the material provided in the fluid phase, in particular, the deposition material through the radiation nozzle 12, and to apply a high voltage with the injection to the configured device. Such a device is a spinning solution or melt storage device, a metering device, a transfer and spinning nozzle for injection, the number and structure of spinning nozzles, a space or chamber in which a wafer support and a wafer are placed for application to a few nanoscale semiconductor wafer. , Process temperature / humidity control device and voltage generator are used in the process before and after the semiconductor manufacturer, manufacturing environment by semiconductor manufacturer, ie the number of process repetitions or insulation layer thickness and specific requirements for each insulation layer according to wafer size, product grade, semiconductor buyer order specification, etc. It can be adapted according to the installation clearance. The spinning nozzle 12 configures the number of spinning nozzles and spinning nozzles according to conditions so that nanofibers having the corresponding thicknesses can be accumulated or thin films are formed on the wafer surface of the corresponding size. Accordingly, the spinning liquid radiated through the spinning nozzle of the device according to the present invention forms a small droplet at the tip of the spinning nozzle, and is branched into numerous nanofibers of finer thickness while being sprayed by a high voltage, and the branched nanofibers are illustrated in FIG. 4. As shown in Fig. 1, the wafer surface or metal wiring is evenly applied or filled. After the coating or filling is completed, the three-dimensional netting film forms a porous insulating film through post-treatment.

That is, the present invention can provide a device having a thin film forming module having an electrospinning function suitable for the above-described process of forming an ultra-low dielectric constant insulating film for semiconductors.

Such a device does not need to use a plurality of reaction gases or to form a high vacuum like a conventional CVD process equipment, and has a relatively simple configuration that does not require a track configuration such as a spin part and a bake part like an SOD device and has a simple process process. Is characteristic.

According to the present invention, there is provided a semiconductor device capable of forming an insulating layer capable of improving the insulating properties between neighboring conductive structures, and a method of manufacturing the same. The semiconductor device according to the present invention has an insulating property between a lower film and an upper film. An insulating film made of nanofiber clusters is formed between a thin film layer made of nanofiber clusters of material or between conductive structures such as bit lines, word lines, or metal lines.

In the present invention, all kinds of organic polymers, organic silicate polymers, and inorganic materials may be used, and the solution phase and the melt phase are not limited. However, there may be a limitation in the selection of materials to satisfy the properties required in the semiconductor process. For example, in the case of the semiconductor low dielectric insulating film to be implemented in the present invention, polyimide and derivatives thereof, aromatic polymers and derivatives thereof including polyaniline, organic silicate polymers and derivatives thereof, fluorinated organic polymers and derivatives thereof, SiCOH and Silicon oxides and derivatives thereof, such as silicon compounds containing the same carbon and the like, but are not necessarily limited thereto. Therefore, no particular limitation is imposed on the solvent for bringing these into solution, and an appropriate solvent for each solute component can be selected. However, it is necessary to choose a solvent with a lower boiling point than the melting point of the polymer according to the process progress, process requirements, and melting point of the polymers, and it is possible to avoid that the boiling point among the selectable solvents is low and other considerations are detrimental to the process. have.

The viscosity of the solution or melt is preferably not particularly limited in the range of 10 to 5,000 cP (centifose) or depending on the needs of the process.

Spinning nozzles for spinning solutions or melts can be chosen in the range of 0.001 to 0.5 mm in diameter, and there is no limitation in this range depending on the needs of the process.

In addition, the nozzle block for installing the spinneret so that the number and arrangement of the spinneret can be arbitrarily adjusted according to the pattern on the wafer has a variable fixing device along the rail in the transverse, vertical and diagonal directions of the nozzle fixing part.

In the apparatus, the high voltage generator may use any product or may be configured separately, but the voltage range should be able to maintain a stable voltage in the range of 1 kV to 50 kV.

The support on which the wafer is placed may have a hot plate or equivalent device in which the wafer is to be fixed and capable of maintaining the temperature of the wafer surface in the range of 20 to 150 ° C.

The chamber through which the insulation film is radiated may include a device capable of maintaining an arbitrary humidity and temperature.

Conductive materials and devices can be installed between the spinning nozzle and the wafer to adjust the distribution of the electric field as needed.

The distance between the spinning nozzle and the wafer is in the range of 50 mm to 250 mm, and the distance is not limited by the viscosity of the spinning liquid, the magnitude of the voltage, and the installation of the electric field distribution control device.

Radiation post-treatment may use heat, UV, electron beam, etc., depending on the characteristics of the spinning liquid, two or more of these may be used in combination or in stages as necessary.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described.

The following examples are intended to illustrate the invention and should not be understood as limiting the scope of the invention.

Example 1

N-methylpyrrolidone / N-methylacetamide was dissolved in a mixed solvent in a weight ratio of 2: 1 so that the concentration of polyamic acid was 18% by weight. 50 g of the above solution was injected into a spinning syringe connected with a spinning nozzle, and the temperature was maintained at 30 ° C. The voltage of the voltage device was set to 13.5 kV and the conditions were set to be discharged for 200 seconds at a rate of 0.015 mg / min through a nozzle tip having a diameter of 0.1 mm. Two spinning nozzles were placed on a 3 × 3 cm wafer specimen, and the surface temperature of the specimen was maintained at 40 ° C. After spinning, primary heat treatment was performed at 100 ° C. for 30 minutes. The specimen was then heated to 280 ° C. for 40 minutes under a nitrogen atmosphere.

As a result, a mesoporous polyimide membrane having a porosity of 60% by the BET measurement method containing nanofibers having an average diameter of about 25 nm was obtained. The surface photograph of the obtained polyimide membrane is shown in FIG. 5, and a cross-sectional photograph is shown in FIG.

Example 2

In the polysilazane represented by [R ₁ R ₂ Si-NR ₃ ] _n , dibutyl ether was added so that the concentration of the inorganic polysilazane polymerized at a weight average molecular weight of 75,000 in which all of the alkyl groups R were hydrogen (H) was 12.5% by weight. Dissolved. 50 g of the above solution was injected into a spinning syringe connected with a spinning nozzle, and a relative humidity of 35% was maintained at room temperature. The voltage of the voltage device was set to 18 kV and the voltage of the collector on which the wafer was mounted was applied to -12 kW. The conditions were set so that they could be discharged for 300 seconds at a rate of 0.012 mg / minute through a nozzle tip with a diameter of 0.10 mm. Two spinning nozzles were placed on a 3 × 3 cm wafer specimen and the surface temperature of the specimen was maintained at 120 ° C. After spinning, heat treatment was performed at 150 ° C. for 1 hour 30 minutes.

As a result, a mesoporous silicon oxide film having a BET measurement porosity of 55% containing nanofibers having a minimum diameter of about 20 nm and a maximum diameter of 50 nm was obtained.

Example 3

20 g of a 17 wt% polysilsesquioxane / PGMEA solution, an organic-inorganic composite, was injected into a spinning syringe connected to a spinning nozzle, maintaining a relative humidity of 35% at room temperature. The voltage of the voltage device was set to 15 kW and the voltage of the wafer collector was also applied to -15 kW. The conditions were set so that they could be discharged for 600 seconds at a rate of 0.010 mg / min through a nozzle tip with a diameter of 0.15 mm. Two spinning nozzles were placed on a 3 × 3 cm wafer specimen and the surface temperature of the specimen was maintained at 120 ° C. After spinning, heat treatment was performed for 1 hour while irradiating UV at 150 ° C.

As a result, a mesoporous organic composite silicon oxide film having a porosity of 60% containing nanofibers having an average diameter of about 30 nm was obtained.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims

(1) Emission using an electrospinning device comprising a high voltage generator, a radiation nozzle electrically connected to one electrode of the high voltage generator and a collector electrically connected to the other electrode (the counter electrode) of the high voltage generator. Supplying a deposition material to be formed of nanofibers to a nozzle, and preparing a wafer in a collecting unit; And

(2) a laminating step of operating the high voltage generator to electrospin the film forming material from the spinning nozzle to form a layer consisting of clusters of nanofibers of film forming material formed by electrospinning on the wafer;

An insulating film forming method comprising a.
The method of claim 1,

An insulating film forming method, characterized in that the film forming material is a low dielectric constant material.
The method of claim 1,

After the lamination step of (2), the first heat-treated wafer for 10 minutes to 1 hour below the boiling point of the solvent or below the melting point of the deposition material, the wafer is formed of a layer consisting of a cluster of nanofibers of the deposition material formed by electrospinning The insulating film forming method further comprises a heat treatment step.
The method of claim 1,

After the lamination step of (2), the wafer in which the layer formed of the nanofibers of the film forming material formed by electrospinning and / or the first heat-treated wafer is subjected to the boiling point of the solvent or the melting point of the film forming material in an inert atmosphere. Method for forming an insulating film further comprises a secondary heat treatment step of heat treatment for 10 minutes to 2 hours.
The method of claim 3, wherein

After the first heat treatment step, further comprising a second heat treatment step of heat-treating the first heat-treated wafer in an inert atmosphere for 10 minutes to 2 hours above the boiling point of the solvent or below the melting point of the deposition material in the inert atmosphere .
A high voltage generator, a radiation nozzle electrically connected to one electrode of the high voltage generator, and a collector electrically connected to the other electrode (the counter electrode) of the high voltage generator, wherein the collector is fixed to the wafer. Insulating film manufacturing apparatus further comprises a fixing means for.