JP2004193262A - Insulating material and insulating film forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulating material showing a sufficient low specific dielectric constant and showing sufficient stability in thermal treatment added after the insulating material or an insulating film is formed. <P>SOLUTION: The insulating material comprises an insulating matter and an inert gas component mixed in the insulating matter. The specific dielectric constant km of the insulating material satisfies a relation of km<ks with the specific dielectric constant ks of the insulating matter. Thus, the insulating material showing not only the sufficient low specific dielectric constant but also showing sufficient stability in thermal treatment added after the insulating material or the insulating film is formed, and an insulating film forming method can be obtained. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an insulating material having a low relative dielectric constant (that is, a low-k) and a method of forming an insulating film including such an insulating material.
[0002]
[Prior art]
The present invention is applicable not only to the manufacture of electronic device materials such as semiconductors or semiconductor devices and liquid crystal devices, but also to a wide range of general insulating materials or insulating films, but here, for convenience of explanation, Description will be made by taking a background art in semiconductor device manufacturing as an example.
[0003]
2. Description of the Related Art In semiconductor devices, high integration and / or high performance has been conventionally promoted by miniaturizing design rules. However, when the design rule becomes finer (for example, about 0.18 μm or less), the wiring resistance and the capacitance between wirings increase remarkably, and it becomes difficult to further improve the performance of the device with the conventional wiring material.
[0004]
For example, to increase the operation speed of a semiconductor device, it is necessary to increase the speed of an electric signal. However, in the conventional aluminum wiring, if the semiconductor device is further miniaturized (for example, to about 0.18 μm or less), the speed of an electric signal flowing through a circuit constituting the semiconductor device is limited (so-called “wiring delay”). "). Therefore, it becomes necessary to use wiring made of a material such as copper (Cu) having a lower electric resistance than aluminum. Since Cu has a lower electric resistance than aluminum, wiring delay is reduced, and even if wiring is thin, electricity flows smoothly.
[0005]
When using a material such as copper having a low electric resistance as described above, it is necessary to use an “insulating film that is less likely to leak electricity” as the insulating film. What matters here is not a DC work but a current leaked as a capacitive coupling (condenser). Therefore, an insulating film having a small ε (relative dielectric constant) is required. By combining such a Cu wiring that easily conducts electricity and an insulating film that does not easily leak electricity, a semiconductor device that operates at extremely high speed can be manufactured.
[0006]
In the era of the conventional aluminum wiring, the insulating film was made of SiO₂Although a film (relative dielectric constant = 4.1) has been used, when a Cu wiring is used, an insulating film having a much lower relative dielectric constant (Low-k) is required. Generally, a Low-k film means a film having a relative dielectric constant of 3.0 or less.
[0007]
As a method for fabricating a low-k insulating film between wirings in such a miniaturized device, SiO 2 is one of the most promising methods in recent years.₂By reacting F or CH with₂Is reduced from 4 to about 3.
[0008]
[Problems to be solved by the invention]
However, in accordance with severe demands in the recent semiconductor industry, there is a strong demand for insulating materials having a lower relative dielectric constant. In order to obtain such an insulating material having a very low relative dielectric constant, it is practically essential to form a porous (porous) film.
[0009]
Although such a porous film gives a favorable low relative dielectric constant, on the other hand, naturally, the strength and the hygroscopicity of the insulating film are severe problems.
[0010]
An object of the present invention is to provide an insulating material and a method of forming an insulating film which have solved the above-mentioned disadvantages of the prior art.
[0011]
Another object of the present invention is to provide an insulating material and a method for forming an insulating film, which not only provide a good low relative dielectric constant but also exhibit good stability in heat treatment or the like applied after forming the insulating material or the insulating film. Is to provide.
[0012]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that an inert gas positively incorporated into an insulating material does not substantially diffuse outside from the insulating material under ordinary heat treatment conditions.
[0013]
As a result of further research, the present inventors have found that such an insulating substance in which an inert gas is positively incorporated not only gives a good low dielectric constant, but also after forming an insulating material or an insulating film. They also showed good stability in the heat treatment and the like added, and found that they were extremely effective for achieving the above object.
[0014]
The insulating material of the present invention is based on the above findings, and is an insulating material containing an insulating substance and an inert gas component mixed in the insulating substance; The relative dielectric constant km satisfies the relationship of km <ks with the relative dielectric constant ks of the insulating material.
[0015]
According to the present invention, furthermore, the base material is irradiated with plasma based on a mixture of an inert gas and a reactive gas under reduced pressure to form an insulating material and mixed into the insulating material. There is provided a method for forming an insulating film, comprising forming an insulating film containing an inert gas component on the base material.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the drawings as necessary. In the following description, “parts” and “%” representing quantitative ratios are based on mass unless otherwise specified.
[0017]
(Insulating material)
The insulating material of the present invention includes an insulating material and an inert gas component mixed in the insulating material, and the relative permittivity km of the insulating material is equal to the relative permittivity ks of the insulating material. , Km <ks. The relative permittivity km of this insulating material is preferably 3 or less, and more preferably 2.7 or less (especially 2.5 or less).
[0018]
(Measurement of relative permittivity)
In the present invention, the ratio km / ks of the relative dielectric constant is preferably 0.92 or less, and more preferably 0.9 or less (particularly 0.88 or less).
Further, the difference (ks-km) in relative permittivity is preferably 0.1 or more, and more preferably 0.12 or more (particularly 0.14 or more).
[0019]
In the present invention, the relative permittivity ks of the insulating substance, the relative permittivity km of the insulating material, and the ratio and difference of the relative permittivity calculated from these can be determined as follows.
<Measurement conditions of relative permittivity>
The CV curve is measured with a mercury probe measuring device of SSM Japan, the capacitance is calculated, and the dielectric constant is calculated from the film thickness. For details of the measurement principle and the measurement method, see http: // www. chipsjp. net / cgi-bin / cybprod. cgi? k = 0244 & p = 03 can be referred to.
[0020]
(Method of measuring inert gas content)
In the insulating material of the present invention, the amount of the inert gas contained in the material is preferably 5% or more, and more preferably 10% or more (particularly 15% or more).
[0021]
In the present invention, the inert gas content in the above-mentioned insulating substance can be measured as follows.
<Method of measuring inert gas content>
By RBS (Rutherford Backscattering Analysis).
That is, the content of an inert gas such as Kr can be measured using HRBS500 manufactured by Kobe Steel, Ltd. as a measuring device. For details of the RBS measurement principle and measurement method, see http: // www. kobelco. co. jp / technookbook / p238. htm.
[0022]
(How to confirm that no inert gas is released)
In the present invention, the fact that the inert gas in the insulating material is not substantially released can be confirmed as follows.
<Confirmation method of inert gas non-emission>
FIG. 4 shows a measurement example in which measurement is performed using TDS (thermal desorption measuring apparatus) of Electronic Science Co., Ltd.
In this TDS measurement, a desorbed gas component can be quantified from a mass fragment spectrum (MF spectrum). When the exhaust speed of the measurement chamber is sufficiently large compared to the pressure change of the measurement chamber caused by the desorbed gas, the change of the partial pressure of the desorbed gas component in the measurement chamber is proportional to the amount of desorption per unit time. In the mass spectrometer, the ion amount and the partial pressure are proportional, so the ion amount and the desorption amount are proportional, and the total desorption amount can be calculated from the area intensity obtained by integrating the ion amount. Known amount of H⁺If the proportionality coefficient between the amount of ions and the amount of desorption is determined using a Si sample implanted with, the amount of hydrogen can be determined from the area intensity of M / z = 2. For molecules other than hydrogen, a proportional coefficient can be calculated from a mass spectrometer coefficient such as ionization difficulty, fragmentation factor, and transmittance between hydrogen and the molecule. Using this proportionality coefficient, molecules other than hydrogen can be quantified.
The principle of TDS measurement and details of the measurement method are based on "N. Hirashita and T. Uchiyama, BUNSEKIKAGAKU, 43, 757 (1994)". Or http: // www. escoltd. co. jp / TDS quantitaurie / quantitative. html.
More specifically, the sample is placed on a heater stage of a vacuum chamber of TDS and the temperature is increased, and the amount of released Kr, Ar, and Xe is measured by QMAS (quadrupole mass spectrometer). If the temperature is 600 ° C. or higher, gas may be emitted. However, since the wiring process is usually performed at 450 ° C. or lower, substantially no gas may be emitted.
[0023]
(Insulating substance)
The insulating material that can be used in the present invention is not particularly limited as long as it can stably hold an inert gas therein (ie, so that the gas is not released under the above-described conditions). Can be appropriately selected from the above insulating materials. TraditionalfilmFrom the viewpoints of adhesion to the substrate and heat conduction, the insulating substance is preferably a substance based on a compound of silicon and oxygen and / or nitrogen. Further, silicon dioxide, silicon nitride, SiOF, Preferably, it is based on one or more substances selected from the group consisting of SiOCH and SiCN.
[0024]
(Inert gas)
The inert gas that can be used in the present invention is not particularly limited as long as it can be stably retained in the insulating substance (that is, the gas is not released under the above-described conditions). An inert gas can be appropriately selected and used. The inert gas is preferably a rare gas so as not to chemically bond with the insulating film, and more preferably, argon, krypton, and / or xenon.
[0025]
(Method of forming insulating film)
In the method for forming an insulating film according to the present invention, the base material is irradiated with plasma based on a mixture of an inert gas and a reactive gas under reduced pressure to mix the insulating material with the insulating material. A film of an insulating material containing the inert gas component is formed on the substrate. This substrate is not particularly limited as long as a film of an insulating material can be formed thereon. From the viewpoint of use of a product (or semi-finished product) formed with a film of an insulating material according to the present invention, the substrate is preferably a substrate for an electronic device.
[0026]
(Substrate for electronic devices)
The substrate for an electronic device that can be used in the present invention is not particularly limited, and may be appropriately selected from one or a combination of two or more known substrates for an electronic device. Examples of such a substrate for an electronic device include a semiconductor material and a liquid crystal device material. Examples of the semiconductor material include, for example, a material mainly containing single crystal silicon.
[0027]
(On the substrate for electronic devices)
In the present invention, “on the electronic device substrate” means that the insulating film to be formed is above the electronic device substrate (that is, above the side of the substrate on which the layers constituting the electronic device are formed). It is enough if it is located. In other words, another insulating layer, a conductor layer (for example, a Cu layer), a semiconductor layer, or the like may be disposed therebetween. Further, needless to say, a plurality of insulating layers, conductor layers (for example, Cu layers), semiconductor layers, and the like, including the insulating film to be formed in the present invention, may be provided as necessary.
[0028]
(Thickness)
The thickness of the insulating film to be formed according to the present invention is not particularly limited, but the following film thickness can be suitably used.
<Suitable film thickness>
A range from 5000 to 10,000 is preferred.
[0029]
(Plasma processing conditions)
In the production of the insulating film of the present invention, the following plasma processing conditions can be suitably used from the viewpoint of the characteristics of the insulating film to be formed. The present invention is characterized in that an inert gas is positively contained in the insulating film. For this reason, the following plasma processing conditions are different from normal conditions mainly in terms of electron temperature and processing temperature.
Noble gas (e.g., Kr, Ar, He or Xe): 100-2000 sccm, more preferably 500-1000 sccm,
Wafer temperature: room temperature (25 ° C.) to 500 ° C., more preferably 100 to 450 ° C., particularly preferably 300 to 400 ° C.
Pressure: 1 to 100 Pa, more preferably 2 to 50 Pa, particularly preferably 3 to 20 Pa
Microwave: 1-10W / cm², More preferably 2 to 8 W / cm²And particularly preferably 3 to 7 W / cm²
[0030]
(Example of suitable conditions)
In the present invention, for example, the following conditions can be suitably used.
Microwave: ± 3W / cm²
Gas: Ar 1000 sccm + TMS 50 sccm, or
Kr 1000sccm + TMS 50sccm
Pressure: 3-20Pa
Substrate temperature: 350 ± 25 ° C
Processing time: 40-90 seconds
[0031]
In the present invention, usable plasma is not particularly limited as long as the above-described insulating film containing an inert gas can be formed. From the viewpoint that an insulating film having a substantially reduced thermal budget can be easily obtained, it is preferable to use plasma having a relatively low electron temperature and high density. By forming an insulating film with a substantially reduced thermal budget, peeling of the film and bleeding of the insulating film such as Cu can be suppressed, and thus a high-quality insulating film can be formed. It becomes.
[0032]
(Preferred plasma)
The characteristics of the plasma that can be suitably used in the present invention are as follows.
Electron temperature: eV 0.5 to 2 eV
Density: IE11 to IE13
Plasma density uniformity: ± 10% or less
[0033]
(Flat antenna member)
In the method of forming an insulating film according to the present invention, it is preferable to form a plasma having a low electron temperature and a high density by irradiating a microwave through a planar antenna member having a plurality of slots. In the present invention, when an insulating film is formed using plasma having such excellent characteristics, a process with particularly small plasma damage and high reactivity at low temperatures can be performed. In the present invention, furthermore, by irradiating microwaves through a planar antenna member (compared to the case of using conventional plasma), there is obtained an advantage that a high-quality insulating film can be easily formed.
[0034]
(One embodiment of plasma irradiation device)
Hereinafter, an exemplary microwave plasma device 100 that can be used as a plasma irradiation device will be described with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same members. The conventional microwave has a frequency of 1 to 100 GHz, but the microwave of the present invention is not limited to this, and has a frequency of about 50 MHz to 100 GHz.
[0035]
Here, FIG. 1 is a schematic block diagram of the microwave plasma device 100. The microwave plasma device 100 of the present embodiment is connected to the microwave source 10, the reaction gas supply nozzle 50, and the vacuum pump 60, and includes the antenna housing member 20, the first temperature control device 30, the processing chamber 40, And a second temperature control device 70.
[0036]
The microwave source 10 is formed of, for example, a magnetron and can generate a microwave (for example, 5 kW) of 2.45 GHz normally. Thereafter, the transmission form of the microwave is converted into a TM, TE, or TEM mode by a mode converter (not shown). In FIG. 1, an isolator that absorbs a reflected wave of the generated microwave returning to the magnetron and an EH tuner or a stub tuner for matching with the load side are omitted.
[0037]
A wavelength shortening member 22 is housed in the antenna housing member 20, and the slot electrode 24 is configured as a bottom plate of the antenna housing member 20 in contact with the wavelength shortening member 22. The antenna housing member 20 is made of a material having a high thermal conductivity (for example, aluminum), and is in contact with the temperature control plate 32 as described later. Therefore, the temperature of the antenna housing member 20 is set to be substantially the same as the temperature of the temperature control plate 32.
[0038]
As the wavelength shortening member 22, a predetermined material having a predetermined dielectric constant and a high thermal conductivity is selected to shorten the wavelength of the microwave. In order to make the density of the plasma introduced into the processing chamber 40 uniform, it is necessary to form many slits 25 in the slot electrode 24 described later. The wavelength shortening member 22 has a function of enabling a large number of slits 25 to be formed in the slot electrode 24. As the wavelength shortening member 22, for example, alumina-based ceramic, SiN, and AlN can be used. For example, AlN has a relative dielectric constant ｔt of about 9, and a wavelength shortening rate n = 1 / (εt) 1/2 = 0.33. Thereby, the speed of the microwave passing through the wavelength shortening member 22 becomes 0.33 times and the wavelength also becomes 0.33 times, and the interval between the slits 25 of the slot electrode 24 described later can be shortened. Is formed.
[0039]
The slot electrode 24 is screwed to the wavelength shortening member 22, and is made of, for example, a cylindrical copper plate having a diameter of 50 cm and a thickness of 1 mm or less. As shown in FIG. 2, the slot electrode 24 has a large number of slits 25 formed spirally and gradually toward the periphery, starting from a position slightly away from the center, for example, at a distance of about several cm. In FIG. 2, the slit 25 is swirled twice. In the present embodiment, a slit group is formed by arranging a pair of slits, which is a pair of slits 25 </ b> A and 25 </ b> B arranged slightly apart in a substantially T shape as described above. The length L1 of each of the slits 25A and 25B is set within a range of about 1/2 of the guide wavelength λ of the microwave to about 2.5 times the free space wavelength, and the width is set to about 1 mm. Although the distance L2 between the outer ring and the inner ring is slightly adjusted, it is set to be substantially the same as the guide wavelength λ.
[0040]
By forming the slits 25A and 25B in this manner, it is possible to form a uniform microwave distribution in the processing chamber 40. A microwave power anti-reflection radiating element 26 having a width of about several mm is formed along the periphery of the disc-shaped slot electrode 24 outside the spiral slit and along the periphery of the disc-shaped slot electrode 24. Thereby, the antenna efficiency of the slot electrode 24 is increased. In addition, the pattern of the slit of the slot electrode 24 of the present embodiment is merely an example, and it goes without saying that an electrode having an arbitrary slit shape (for example, an L-shape) can be used as the slot electrode.
[0041]
The temperature control device 30 is connected to the antenna housing member 20. For the temperature control plate 32, a material having a good thermal conductivity such as stainless steel and easy to process the flow path is selected. Each of the temperature control plate 32 and the flow path can have an arbitrary shape.
[0042]
The temperature control plate 32 is in contact with the antenna housing member 20, and the antenna housing member 20 and the wavelength shortening member 22 have high thermal conductivity. As a result, by controlling the temperature of the temperature control plate 32, the temperatures of the wavelength shortening member 22 and the slot electrode 24 can be controlled.
[0043]
On the other hand, if the temperature is constant, the slot electrode 24 does not deform even if it is disposed at a high temperature. In the plasma CVD apparatus, if water is present in the processing chamber 40 in a liquid or mist state, it will be mixed as an impurity into the film of the semiconductor wafer W, so that the temperature must be raised as much as possible. Considering that a member such as an O-ring 90 for sealing between the processing chamber 40 and a dielectric 28 described later has a heat resistance of about 80 to 100 ° C., the temperature control plate 32 (that is, the slot electrode 24) is used. ) Is controlled to be about ± 5 ° C. with reference to 70 ° C., for example. The set temperature such as 70 ° C. and the allowable temperature range such as ± 5 ° C. can be arbitrarily set depending on required processing, heat resistance of constituent members, and the like.
[0044]
In the above embodiment, the temperature control plate 32 and the antenna housing member 20 are separate members, but the function of the temperature control plate 32 may be provided to the antenna housing member 20. For example, by forming the flow path 33 on the upper surface and / or the side surface of the antenna housing member 20, the antenna housing member 20 can be directly cooled. Further, a temperature control plate may be provided around the slot electrode 24, or a flow path may be formed in the slot electrode 24 itself so as not to hinder the arrangement of the slit 25 (FIG. 2).
[0045]
The dielectric 28 is disposed between the slot electrode 24 and the processing chamber 40. The slot electrode 24 and the dielectric 28 are surface-bonded firmly and confidentially by, for example, brazing. Alternatively, a copper thin film is patterned on the back surface of the fired ceramic dielectric 28 by screen printing or the like into the shape of the slot electrode 24 including the slit, and the copper thin film is slotted on the copper foil so as to be baked. The electrode 24 may be formed. The dielectric 28 and the processing chamber 40 are joined by an O-ring 90.
[0046]
The dielectric 28 is made of aluminum nitride (AlN) or the like. When the pressure of the processing chamber 40 in a reduced pressure or vacuum environment is applied to the slot electrode 24, the slot electrode 24 is deformed or the slot electrode 24 is exposed to the processing chamber 40. To prevent spattering and copper contamination. If necessary, the dielectric 28 may be made of a material having low thermal conductivity to prevent the slot electrode 24 from being affected by the temperature of the processing chamber 40.
[0047]
Alternatively, the dielectric 28 can be formed of a material having a high thermal conductivity (for example, AlN), like the wavelength shortening member 22. In this case, the temperature of the slot electrode 24 can be controlled by controlling the temperature of the dielectric 28, and the temperature of the wavelength shortening member 22 can be controlled via the slot electrode 24. In this case, a flow path can be formed in the dielectric 28 so as not to hinder the introduction of the microwave into the processing chamber 40. The above-described temperature control can be arbitrarily combined.
[0048]
The processing chamber 40 has a side wall and a bottom portion formed of a conductor such as aluminum, and is entirely formed in a cylindrical shape. The inside of the processing chamber 40 can be maintained at a predetermined reduced pressure or a vacuum sealed space by a vacuum pump 60 described later. . In the processing chamber 40, a heating plate 42 and a semiconductor wafer W as an object to be processed are stored thereon. In FIG. 1, an electrostatic chuck and a clamp mechanism for fixing the semiconductor wafer W are omitted for convenience.
[0049]
The heating plate 42 has a configuration similar to that of the heater device 38 and controls the temperature of the semiconductor wafer W. For example, in the plasma CVD process, the hot plate 42 heats the semiconductor wafer W to, for example, about 450 ° C. In the plasma etching process, the hot plate 42 heats the semiconductor wafer W to about 80 ° C. or lower, for example. These heating temperatures by the hot plate 42 differ depending on the process. In any case, the heating plate 42 heats the semiconductor wafer W so that moisture as an impurity does not adhere to or enter the semiconductor wafer W. The second temperature control device 70 can control the magnitude of the heating current flowing through the heating plate 42 according to the temperature measured by the temperature sensor 72 that measures the temperature of the heating plate 42.
[0050]
A gas supply nozzle 50 made of quartz pipe for introducing a reaction gas is provided on a side wall of the processing chamber 40, and the nozzle 50 is connected to a reaction gas source 58 through a gas flow path 52 via a mass flow controller 54 and an on-off valve 56. It is connected to the. For example, when a silicon nitride film is to be deposited, a predetermined mixed gas (for example, Neon, xenon, argon, helium, radon, krypton,₂And H₂Plus NH) to NH₃, SiH₄, TMS (trimethylsilane) gas or the like can be selected.
[0051]
The vacuum pump 60 can evacuate the processing chamber 40 to a predetermined pressure (for example, 0.001 to 0.01 Pa). In FIG. 1, the detailed structure of the exhaust system is also omitted.
[0052]
(Operation of plasma processing apparatus)
Next, the operation of the microwave plasma processing apparatus 100 of the present embodiment configured as described above will be described.
[0053]
Referring to FIG. 1, semiconductor wafer W is housed in processing chamber 40 by a transfer arm via a gate valve (not shown) provided usually on a side wall of processing chamber 40. Thereafter, the lifter pins (not shown) are moved up and down to place the semiconductor wafer W on a predetermined mounting surface.
[0054]
Next, an insulating film to be formed is formed from the nozzle 50 while maintaining the inside of the processing chamber 40 at a predetermined processing pressure, for example, 3 Pa, from one or more reaction gas sources 58 in which a mixed gas of argon and nitrogen is mixed. The gas is introduced into the processing chamber 40 while controlling the flow rate through the mass flow controller 54 and the on-off valve 56 so that the inert gas component is contained therein.
[0055]
On the other hand, the microwave from the microwave source 10 is introduced into the wavelength shortening member 22 in the antenna housing member 20 through, for example, a rectangular waveguide or a coaxial waveguide (not shown) in, for example, a TEM mode. The microwave that has passed through the wavelength shortening member 22 has its wavelength shortened, enters the slot electrode 24, and is introduced into the processing chamber 40 through the slit 25 via the dielectric 28. Since the wavelength shortening member 22 and the slot electrode 24 are temperature-controlled, there is no deformation due to thermal expansion or the like, and the slot electrode 24 can maintain an optimal slit length. This allows the microwaves to be introduced into the processing chamber 40 uniformly (i.e., without partial concentration) and at the desired overall density (i.e., without loss of density).
[0056]
Thereafter, the microwave converts the reaction gas into plasma, and irradiates the object to be processed disposed on the electronic device substrate with plasma to form the insulating film. The formation of the insulating film is performed, for example, for a predetermined period of time, and then the semiconductor wafer W is taken out of the processing chamber 40 from the gate valve (not shown). Since microwaves having a desired density are uniformly supplied to the processing chamber 40, a film having a desired thickness is uniformly formed on the wafer W.
[0057]
As described above, the modes of the device that can be suitably used in the present invention have been described, but the present invention can be variously modified and changed within the scope of the gist. For example, since the microwave plasma processing apparatus 100 of the present invention does not prevent the use of electron cyclotron resonance, it may include a coil for generating a predetermined magnetic field. Further, the object to be processed in the present invention is not limited to a semiconductor wafer, but includes an LCD or the like.
[0058]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
The Low-k films evaluated in each of FIGS. 5 to 7 described above were produced by a method having the following steps.
[0059]
(1): Substrate
The substrate is a 20cm (8 inch) P-type silicon substrate,surfaceThe orientation (100) was used.
[0060]
(2): Cleaning before gate oxidation
APM (a mixture of ammonia: hydrogen peroxide: pure water = 1: 2: 10, 60 ° C.), HPM (a mixture of hydrochloric acid: hydrogen peroxide: pure water = 1: 1: 10, 60 ° C.) and RCA cleaning combined with DHF (hydrofluoric acid: pure water = 1: 100 mixed solution, 23 ° C.) removed a natural oxide film and contaminants (metals, organic substances, particles). RCA cleaning is performed for 10 minutes of APM → 10 minutes of pure water rinse → 3 minutes of DHF → 10 minutes of pure water rinse → 10 minutes of HPM → 10 minutes of pure water rinse → 5 minutes of final rinse of pure water, followed by IPA (isopropyl alcohol, 220 ° C) Drying was performed for 15 minutes to dry the water on the wafer.
[0061]
(Formation of Kr-containing insulating film)
A silicon oxide film containing Kr was formed on the silicon substrate subjected to the process (2) by the following method.
[0062]
Referring to FIG. 1, an electronic device substrate made of silicon is introduced into processing container 40 of substrate processing apparatus 100 shown in FIG. 1 as substrate W to be processed, and Kr and TMS are supplied from gas supply nozzle 50. A Kr-containing silicon oxide film having a thickness of 500 nm was formed on the surface of the substrate W for an electronic device by introducing a gas mixture of
[0063]
<Processing conditions>
TMS gas: 50 sccm
NU₂： 50sccm
Kr gas: 1000 sccm
Wafer temperature: 400 ° C
Pressure: 6: 7Pa
Microwave: 3W / cm²
Processing time: 1 minute
[0064]
Example 2
(Characteristics of Kr-containing insulating film)
Regarding the Kr-containing silicon oxide film formed in Example 1, the inert gas is not released from the silicon oxide film by various subsequent processes, the strength of the Kr-containing silicon oxide film, and the hygroscopicity of the Kr-containing silicon oxide film. It was confirmed. As shown below, the Kr-containing silicon oxide film formed in Example 1 had excellent characteristics in these characteristics.
[0065]
Example 3
(Confirmation of device characteristics)
Using the insulating material obtained in Example 1 (that is, a Kr-containing silicon oxide film is formed on a silicon substrate), a transistor structure is manufactured as follows, and the ring oscillator characteristics of the transistor are measured. It was measured. As shown below, each of the ring oscillators formed using the insulating material of the present invention exhibited good device characteristics.
[0066]
【The invention's effect】
INDUSTRIAL APPLICABILITY As described above, according to the present invention, an insulating material which not only gives a good low relative dielectric constant but also shows good stability even in a heat treatment applied after forming an insulating material or an insulating film, and an insulating film A method of forming is provided.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing the structure of a microwave plasma processing apparatus that can be suitably used in the present invention.
FIG. 2 is a schematic plan view for explaining a specific configuration example of a slot electrode that can be used in the microwave plasma processing apparatus shown in FIG.
[Explanation of symbols]
10. Microwave source
20: antenna storage member
22 ... wavelength shortening member
24 ... Slot electrode
25 ... Slit
28 ... Dielectric
30 first temperature control device
40 ... plasma processing chamber
42 ... Hot plate
50: reaction gas supply nozzle
58 ... Reaction gas source
60 ... Vacuum pump
70: second temperature control device
72 ... Temperature sensor

Claims (12)

An insulating material including an insulating material and an inert gas component mixed into the insulating material; and
An insulating material characterized in that the relative permittivity km of the insulating material satisfies the relationship of km <ks with the relative permittivity ks of the insulating substance. The insulating material according to claim 1, wherein a ratio of relative permittivity km / ks is 0.92 or less. The insulating material according to claim 1 or 2, wherein a difference (ks-km) in relative permittivity is 0.1 or more. The insulating material according to claim 1, wherein the relative dielectric constant km is 2.90 or less. The insulating material according to any one of claims 1 to 4, wherein the content of the inert gas component in the insulating material is 5% or more. The insulating material according to any one of claims 1 to 5, which has a film-like shape. The insulating material according to any one of claims 1 to 6, wherein the inert gas component is argon, krypton, and / or xenon. The insulating material according to any one of claims 1 to 7, wherein the insulating material is a material based on a compound of silicon and oxygen and / or nitrogen. 9. The insulating material according to any of the preceding claims, wherein the insulating material is based on one or more substances selected from the group consisting of silicon dioxide, silicon nitride, SiOF, SiOCH, and SiCN. The insulating material according to any one of claims 1 to 8, wherein the insulating substance is a compound containing C and F. Irradiate the substrate with a plasma based on a mixture of an inert gas and a reactive gas under reduced pressure,
A method for forming an insulating film, comprising: forming an insulating film containing an insulating substance and an inert gas component mixed in the insulating substance on the base material. The method for forming an insulating film according to claim 11, wherein the base is a base for an electronic device.

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