JP2007318070A - Insulating film material, film forming method using the same, and insulating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an insulating film useful for an interlayer dielectric of a semiconductor device, and having a low dielectric constant and strong mechanical strength. <P>SOLUTION: Using a tetravinylsilane as a material for an insulating film, film formation is executed by a plasma CVD method. The film formation may be executed in the presence of a noble gas such as helium, argon or xenon, chain hydrocarbons having the number of carbons of 2-3 such as ethane or propane, or chain unsaturated hydrocarbon having a hydrocarbon group having the number of carbons of 2-3 such as ethylene, acetylene or propylene. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an insulating film material used when forming an insulating film such as an interlayer insulating film of a semiconductor device, a film forming method using the same, and an insulating film. A low dielectric constant and high strength insulating film is obtained. It is intended to be.

  As semiconductor devices are highly integrated, wiring layers are being miniaturized. However, in the fine wiring layer, the influence of the signal delay in the wiring layer becomes large, which hinders speeding up. Since this signal delay is proportional to the resistance of the wiring layer and the wiring interlayer capacitance, it is essential to reduce the resistance of the wiring layer and reduce the wiring interlayer capacitance in order to achieve high speed.

Therefore, recently, copper having a lower resistivity than conventional aluminum is used as a material for the wiring layer, and the interlayer insulating film is changed from SiO ₂ (relative dielectric constant = 4.1) to dielectric constant in order to reduce the wiring interlayer capacitance. Low SiOF (relative dielectric constant = 3.7). However, the value of the dielectric constant required for the interlayer insulating film is gradually reduced, and it is expected that a value as small as 2.4 or less will be required in the near future.

  When the wiring layer is formed from copper, a technique called a damascene method is employed for forming the wiring layer. Damascene method is to form wiring grooves in interlayer insulation film by dry etching in advance by resist masking, deposit copper on this, and then remove the deposited copper other than wiring grooves by chemical mechanical polishing (CMP) This is a method of forming a wiring layer made of copper.

In this chemical mechanical polishing method, copper is polished and removed while a load is applied to the wafer with a slurry and a pad. Therefore, the interlayer insulating film is subjected to a force from the upper side and the horizontal direction. Failure to break or peel occurs.
When the interlayer insulating film is a SiO ₂ film formed by CVD using tetraethoxysilane, the film has high strength and is not damaged by chemical mechanical polishing. However, if the SiO ₂ film is made porous in order to lower the dielectric constant, the strength is greatly reduced and the film becomes brittle.

The Young's modulus is generally used as an index of the strength of the insulating film, but the SiO ₂ film using tetraethoxysilane has a thickness of about 80 GPa, but the SiOF film is 70 GPa, and further the SiOC film is 12 GPa. Drop to.
Recent porous films using organic siloxane raw materials and organic raw materials have been found to have only about 2 to 4 GPa of strength, and it has become impossible to perform chemical mechanical polishing, which greatly reduces the manufacturing yield of semiconductor devices. It is a cause.

There have been many proposals to use a film having a reduced dielectric constant as an interlayer insulating film of a semiconductor device, and some of them are shown below.
JP 2002-252228 A JP 2002-256434 A JP 2004-200626 A JP 2004-214161 A

  Therefore, an object of the present invention is to obtain an insulating film having a low dielectric constant and high mechanical strength useful for an interlayer insulating film of a semiconductor device.

To solve this problem,
The invention according to claim 1 is an insulating film material for plasma CVD which is represented by the following chemical formula (1) and the obtained insulating film is composed of only silicon, carbon and hydrogen.

The invention according to claim 2 is a film forming method for forming an insulating film made of only silicon, carbon, and hydrogen by plasma CVD using the insulating film material according to claim 1.
The invention according to claim 2 is the film forming method according to claim 2, wherein the film formation is performed with at least one chain hydrocarbon having 2 to 3 carbon atoms.

The invention according to claim 4 is the film forming method according to claim 3, wherein the film is formed by further entraining at least one of helium, xenon, argon, krypton, and hydrogen.
The invention according to claim 5 is the film forming method according to claim 3 or 4, wherein the chain hydrocarbon having 2 to 3 carbon atoms contains an unsaturated bond.

The invention according to claim 6 forms the film while changing any one or more of the high frequency power for plasma generation, the flow rate of the film forming gas, and the film forming pressure during the film formation by the plasma CVD method. The film forming method according to any one of the above.
The invention according to claim 7 is the film forming method according to any one of claims 2 to 6, wherein the film is formed by adding porodiene during film formation.

The invention according to claim 8 is an insulating film obtained by the film forming method according to claim 2.
The invention according to claim 9 is the insulating film according to claim 8, wherein the dielectric constant changes in the thickness direction.
The invention according to claim 10 is the insulating film according to claim 8, wherein the density changes in the thickness direction.

  According to the present invention, the insulating film formed by the plasma CVD method using this insulating film material has a low dielectric constant and high mechanical strength, and the interlayer insulating film is damaged even by the chemical mechanical polishing method. Thus, an insulating film having a dielectric constant of 2.1 to 4.7 and a Young's modulus of 3.5 to 18 GPa can be obtained.

  Conventionally, many organic silicon-based materials have been proposed as materials for lowering the dielectric constant while maintaining the mechanical strength of the insulating film. In the organic silicon materials proposed so far, the organic chain in the organic silicon insulating film is used only for the purpose of introducing a low dielectric constant substance into the insulating film, and is disposed at the end of the bond. The network structure is proposed based on the idea that it is formed only by Si—O—Si bonds.

On the other hand, the present inventor conducted a theoretical study on the insulating film structure, and included not only the Si—O—Si bond but also the Si— (hydrocarbon) —Si bond as a network. It has been found that a rate material can be obtained.
Specifically, in the structure in which (hydrocarbon) is CH ₂ , C ₂ H ₄ or C ₃ H ₆ and the oxygen coordination number of Si is 1, the dielectric constant is greatly reduced and the strength is hardly reduced. Found no. Various materials that can realize this were studied, and the above-mentioned insulating film material was discovered.

  Furthermore, when an organic silicon compound having an unsaturated bond is used as the insulating film material, a rapid increase in film formation rate is recognized, which contributes to an increase in throughput.

The present inventor conducted a theoretical study on the insulating film structure and verified how the physical properties change between when the hydrocarbon is terminated and when the network structure is taken.
Changes in dielectric constant and Young's modulus in a model in which a model structure of a 90 nm node low dielectric constant film is created as a reference structure and the two Si—CH ₃ terminations are replaced with Si—C ₂ H ₄ —Si network structure I investigated.
The reference structure is a model of a plasma CVD film that uses tetracyclotetrasiloxane as a raw material, and has the same atomic group as the one that was actually analyzed for the film, and was created to reproduce the measured composition. It is.

FIG. 1 shows the Young's modulus and dielectric constant of the model structure obtained by calculation. In FIG. 1, a curve A is for a model (reference structure) of a plasma CVD film using tetracyclotetrasiloxane as a raw material, and a curve B is a Si—C ₃ terminal of two Si—CH ₃ ends of this insulating film. it is for substitution model in ₂ H ₄ -Si network structure.
1 clearly suggests that the model structure having a hydrocarbon network may have a high Young's modulus and a low dielectric constant.

  Therefore, when compared in terms of the same mechanical strength, the SiOCH film having a hydrocarbon bridge has a lower dielectric constant. Therefore, a model structure having a hydrocarbon network is a better material for a low dielectric constant film. I know that there is. From the above calculation results, it was found that the strength could be increased by forming a hydrocarbon network.

  Therefore, various materials that can realize such a structure were studied, and the material represented by the above chemical formula (1) was discovered.

By the way, regarding the tetravinylsilane represented by the above chemical formula (1), a method for producing an insulating film in a semiconductor wiring by using tetravinylsilane has already been disclosed in the following prior art.
JP 2005-071741 A, JP 2005-23318 A, JP 2005-045058 A, JP 2004-221275 A, JP 2004-235548 A, JP 2006-152063 A, JP JP 2005-310861 A, JP 2004-289105 A.

  However, in these prior documents, when tetravinylsilane is used as a film forming material by the plasma CVD method, most of them are disclosed in JP 2005-045058 A, JP 2004-221275 A, JP 2004-235548 A, JP 2005-310861 A and JP 2004-289105 A) are disclosed for use as a copper diffusion prevention film or an etch stop film, and there is no description as a bulk film. Although the stop performance is described, there is no description in the dielectric constant of the generated insulating film.

  Further, it is widely known that commonly used copper diffusion prevention films and etch stop films have a higher relative dielectric constant than bulk films. For this reason, it is unlikely that the insulating films according to these prior documents have a very low relative dielectric constant as compared with conventional copper diffusion prevention films and etch stop films.

Although only described in JP-A-2005-071741 as an interlayer insulating film material by plasma CVD, a compound containing oxygen atoms is added.
Therefore, it is not shown that a low dielectric constant insulating film is formed without adding a material containing oxygen atoms to tetravinylsilane in the present invention.

The present inventor has a low dielectric constant as a result Si- (hydrocarbon) theoretical study of membrane -Si network _{(hydrocarbon: CH 2, C 2 H 4} , C 3 H 6, C 4 H 8) only by the membrane It was found that a low dielectric constant insulating film can be formed by using tetravinylsilane as a raw material for the purpose of film formation.

At this time, a chain hydrocarbon having 2 to 3 carbon atoms can be used as an additive gas with a rare gas such as helium or hydrogen as a base gas. In this case, the deposition rate (deposition rate, deposition rate) is maintained. The dielectric constant can be reduced.
If this effect is promoted and film formation is performed using chain hydrocarbons having 2 to 3 carbon atoms as the base gas, a greater effect of lowering the dielectric constant can be obtained. It is possible to control the reduction rate of the dielectric constant while maintaining the deposition rate by the mixing ratio of the hydrocarbon with the chamber.

In addition, since the effect of reducing the dielectric constant varies depending on the type of gas to be added, it is possible to mix different types of chain hydrocarbons having 2 to 3 carbon atoms, and to use rare gases such as helium and hydrogen. It is also possible to use a mixture of three or more.
In particular, when a hydrocarbon compound having an unsaturated bond is used, an extremely large dielectric constant lowering effect can be obtained as compared with a compound having only a saturated bond.
Furthermore, when hydrogen is used, attention must be paid to the amount used, but the generation of terminal groups can be suppressed and a film with higher strength can be formed.
Further, under the film forming conditions, a low plasma generating high frequency power (RF power) is effective for reducing the dielectric constant.

When the structure of the insulating film at this time is confirmed by FT-IR, as shown in FIG. 2, the insulating film formed with low RF power is equivalent to the C film around 1600 cm ⁻¹ with respect to the insulating film formed with high RF power. It is clear that the peak due to the = C bond, the peak due to the Si-H bond near 2150 cm ^-1 rapidly decreases, and the peak of Si- (CH ₂ ) _n -Si near 1050 cm ^-1 increases rapidly. became. When C = C and the peak ratio of Si—H and Si— (CH ₂ ) _n —Si are both 1: 2 or more, it has excellent insulating properties and low dielectric constant, and has an excellent low dielectric constant insulating film. It becomes.

  If this is further advanced, the power will be lower and the plasma may not ignite. In such a case, after introducing the wafer into the chamber chamber, He or the like is introduced in advance, and after igniting plasma with a power lower than the purpose of film formation for a moment, the chamber is evacuated and the film formation conditions are adjusted to ignite the plasma. It was found that it was possible to ignite stably and form a film.

In addition, when forming a film using this tetravinylsilane, the dielectric constant, film density, etc. can be changed by changing the RF power, film forming pressure, and gas flow rate of the film forming gas during film formation. A film having different characteristics in the thickness direction can be formed in one film.
These RF power, film forming pressure, and film forming gas flow rate can be changed independently or simultaneously, and can be changed in consideration of characteristics such as dielectric constant and film density of the film to be formed.
Also, when changing the dielectric constant and film density during film formation, it is most effective to change the RF power, and changing the RF power is instantaneous compared to changing the film formation pressure or the flow rate of the film formation gas. Can be controlled.

  Japanese Patent No. 3197007 and Japanese Patent No. 3197008 disclose a film forming method for forming an insulating film having a lower dielectric constant by changing the residence time. The factor of the residence time is the film formation pressure. The film forming gas flow rate, the film forming temperature, and the distance between the electrodes are not described with RF power. Further, there is no description that the dielectric constant and density are controlled by changing the residence time during film formation. In the insulating film using tetravinylsilane as a raw material, even if the residence time is the same, if the RF power is different, the dielectric constant becomes a different film, and the influence of the change in the RF power on the dielectric constant is large.

  Insulating films with a low dielectric constant have a low density, so there is a possibility that the dielectric constant will greatly deteriorate due to moisture absorption. However, the dielectric constant can be changed by changing conditions such as RF power, pressure, and gas flow rate during film formation. However, it is possible to prevent moisture absorption by thinning a high-density film and covering the surface with a high-density layer. As a result, a film with a low dielectric constant can be formed. There are merits such as improving the etching property change and adhesion by forming a film.

  Furthermore, a substance called porogen is introduced at the time of film formation, and is removed by annealing, electron beam irradiation, ultraviolet irradiation, or the like, whereby holes are introduced into the insulating film, and the dielectric constant can be further reduced. As the porogen to be introduced at the same time, generally used 1-methyl-4-isopropyl-1,3-cyclohexadiene, cyclohexane oxide and the like can be used.

Hereinafter, the present invention will be described in detail.
The insulating film material for plasma CVD of the present invention is tetravinylsilane, which is a compound represented by the above chemical formula (1).

The film forming method of the present invention will be described.
The film forming method of the present invention basically forms a film by the plasma CVD method using the insulating film material represented by the above chemical formula (1). In this case, the film forming gas fed into the chamber of the film forming apparatus and used for film forming is a mixed gas in which a base gas and / or an additive gas is mixed in addition to a gas made of an insulating film material.

The base gas refers to a gas that occupies 50% by volume or more of the volume excluding the gas composed of the insulating film material, and the additive gas refers to 50% of the volume excluding the gas composed of the insulating film material. Gas that occupies less than volume%.
The insulating film material is used after being gasified by vaporization by bubbling using an inert gas such as helium, vaporization by a vaporizer, or vaporization by heating a material container.

Next, a film forming method using tetravinylsilane which is an insulating film material represented by the chemical formula (1) will be described.
Since tetravinylsilane does not contain oxygen atoms in the molecule, the fine structure of the insulating film obtained therefrom is Si- (hydrocarbon) -Si network structure (hydrocarbon: CH ₂ , C containing only silicon, carbon and hydrogen). ₂ H ₄ , C ₃ H ₆ , C ₄ H ₈ ), and for that purpose, the base gas and additive gas in the film-forming gas sent into the chamber of the film-forming apparatus include: It is necessary to use one that does not contain oxygen atoms in the molecule.

  Therefore, one or more of rare gases such as helium, argon, krypton, and xenon and hydrogen are used as the base gas, and carbon such as ethane, ethylene, acetylene, propane, propyne, and propylene is used as the additive gas. One or more chain hydrocarbons having 2 to 3 carbon atoms, preferably one or more chain hydrocarbons having 2 to 3 carbon atoms having an unsaturated bond such as ethylene, acetylene, and propylene are used.

In addition, as the base gas, one or more chain hydrocarbons having 2 to 3 carbon atoms such as ethane, ethylene, acetylene, propane, propyne and propylene, preferably carbon number having an unsaturated bond such as ethylene, acetylene and propylene. One or more of 2 to 3 chain hydrocarbons may be used, and any one or more of a gas such as helium, argon, krypton, and xenon and hydrogen may be used as an additive gas.
Further, the ratio of the tetravinylsilane gas in the film forming gas is 5 to 90% by volume, preferably 25 to 50% by volume, and more preferably 30 to 35% by volume.

By using the accompanying gas in combination, for example, when chain hydrocarbons having 2 to 3 carbon atoms are accompanied, the dielectric constant can be greatly lowered while maintaining the deposition rate (deporate).
When hydrogen is accompanied, the terminal group can be suppressed, and a higher strength film can be formed. However, care must be taken because the dielectric constant may be significantly increased if the conditions are not met.

Further, during film formation, film formation can be performed by changing one or more of plasma generating high frequency power (RF power), film formation pressure, and film formation gas flow rate. By adopting, the dielectric constant and density in the thickness direction of the insulating film obtained can be controlled. The change in dielectric constant and density may be continuous or stepwise.
Thus, for example, the surface portion of the insulating film is composed of a layer having a high density and a high dielectric constant, the inner portion is composed of a layer having a low density and a low dielectric constant, and the dielectric constant of the entire insulating film is low. In addition, the effect of increasing the strength at the surface portion and further suppressing moisture absorption of the insulating film can be obtained.

Further, as described above, it is desirable to form a film with the RF power as small as possible.
The RF power during film formation varies slightly depending on the plasma CVD film forming apparatus, but is preferably less than 250 W, and a film with fewer termination groups can be formed as low as 50 to 100 W.

As the plasma CVD method, a well-known method is used. For example, the film can be formed using a parallel plate type plasma film forming apparatus as shown in FIG.
The plasma film forming apparatus shown in FIG. 3 includes a chamber 1 that can be depressurized. The chamber 1 is connected to an exhaust pump 4 through an exhaust pipe 2 and an on-off valve 3. The chamber 1 is provided with a pressure gauge (not shown) so that the pressure in the chamber 1 can be measured. In the chamber 1, a pair of flat plate-like upper electrode 5 and lower electrode 6 that are opposed to each other are provided. The upper electrode 5 is connected to a high frequency power source 7 so that a high frequency current is applied to the upper electrode 5.

The lower electrode 6 also serves as a mounting table on which the substrate 8 is mounted. A heater 9 is built in the lower electrode 6 so that the substrate 8 can be heated.
A gas supply pipe 10 is connected to the upper electrode 5. A film-forming gas supply source (not shown) is connected to the gas supply pipe 10, and a film-forming gas is supplied from the film-forming gas supply device, and this gas is formed in the upper electrode 5. It flows out through the through-holes while diffusing toward the lower electrode 6.

  The film forming gas supply source is provided with a vaporizer for vaporizing the insulating film material and a flow rate adjusting valve for adjusting the flow rate, as well as a supply device for supplying a base gas and an additive gas. A supply device is provided, and these gases also flow through the gas supply pipe 10 and flow out from the upper electrode 5 into the chamber 1.

The substrate 8 is placed on the lower electrode 6 in the chamber 1 of the plasma film forming apparatus, and the film forming gas is sent into the chamber 1 from a film forming gas supply source. A high frequency current is applied to the upper electrode 5 from the high frequency power source 7 to generate plasma in the chamber 1. As a result, an insulating film generated by the gas phase chemical reaction from the film forming gas is formed on the substrate 8.
As the plasma CVD method, in addition to the parallel plate type, ICP plasma, ECR plasma, and magnetron plasma can be used, and dual frequency excitation plasma that introduces a high frequency to the lower electrode of the parallel plate type apparatus is used. You can also.

The film forming conditions in this plasma film forming apparatus are preferably in the following range, but are not limited thereto.
Insulating film material flow rate: 25 to 100 cc / m (in the case of 2 or more types, the total amount)
Additive gas flow rate: 0 to 50 cc / min
Base gas flow rate: 25-100 cc / min
Pressure: 1-10 torr
RF power: 50 to 500 W, preferably 50 to 250 W
Substrate temperature: 300-400 ° C
Deposition thickness: 200 nm

In the insulating film material used at this time, the total of the metal components contained in the material is preferably less than 100 ppb, and the nitrogen component is preferably less than 10 ppm.
The metal component in the insulating film material is preferably small because it deteriorates the leak characteristics of the formed film, and nitrogen is preferably small because it has an adverse effect such as generation of amine when performing ArF resist after film formation.

The insulating film of the present invention is formed by a plasma CVD reaction using a plasma film forming apparatus using the above-described insulating material for plasma CVD, or a base gas and an additive gas, and has a dielectric constant of 2 0.1 to 4.7, Young's modulus becomes 3.5 to 18 GPa, and mechanical strength is high.
For this reason, this insulating film is not damaged by chemical mechanical polishing or peeled off from the substrate.

In addition, in the insulating film obtained from the insulating film material represented by the chemical formula (1), all of the networks constituting the insulating film include Si- (hydrocarbon) -Si bonds, and (hydrocarbon) There has been a _{CH 2,} C 2 _H4, a C 3 _{H 6} structure.

Examples are shown below.
The measurement of the film thickness, dielectric constant, and density of the insulating film in the examples was performed as follows.
The film thickness was measured using a spectroscopic ellipsometer. The dielectric constant was measured using a mercury probe with a film thickness of 400 nm or more. The density was measured by XRR. However, in some embodiments, there is a sample whose dielectric constant is measured with a film thickness of less than 400 nm.

  In the measurement of an insulating film having a plurality of dielectric constants and densities, the film formation conditions are changed, and a film before the change, a film in the middle of change, and a film after the change of conditions are formed. The film thickness, dielectric constant, and density of these films are measured. The measured value of each film is the integrated value of the film so far, so the difference from the previous measured value is the dielectric constant and density after the change of conditions (in the following examples, expressed as Δ dielectric constant and Δ density, respectively) ).

Example 1
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative permittivity: 2.73
Young: 10.5GPa
Deposition: 40 nm / min

Example 2
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 400 ° C
Relative permittivity: 2.55
Young's modulus: 7.8 GPa
Deposition: 20 nm / min

Example 3
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: 7 torr
RF power: 150W
Substrate temperature: 350 ° C
Relative dielectric constant: 2.98
Young's modulus: 12 GPa
Deporate: 60nm / min

Example 4
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: 7 torr
RF power: 250W
Substrate temperature: 350 ° C
Relative permittivity: 3.21
Young's modulus: 18 GPa
Deposition: 110 nm / min

Example 5
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: 0.5 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative permittivity: 3.82
Young's modulus: 17.5 GPa
Deposition: 40 nm / min

Example 6
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: 0.5 torr
RF power: 300W
Substrate temperature: 350 ° C
Relative permittivity: 4.57
Young's modulus: 20.1 GPa
Deposition: 200 nm / min

Example 7
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: 7 torr
RF power: 300W
Substrate temperature: 350 ° C
Relative permittivity: 4.73
Young's modulus: 15 GPa
Deposition: 230 nm / min

Example 8
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25cc / min
Base gas name: Ethane Base gas flow rate: 50cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative permittivity: 2.69
Young's modulus: 4.61 GPa
Deposition: 40 nm / min

Example 9
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Ethylene base gas Flow rate: 50cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Dielectric constant: 2.50
Young's modulus: 4.5 GPa
Deposition: 40 nm / min

Example 10
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 30cc / min
Addition gas name: Ethane addition gas flow rate: 20cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative permittivity: 2.69
Young's modulus: 4.5 GPa
Deposition: 40 nm / min

Example 11
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25cc / min
Base gas name: Helium base gas flow rate: 30cc / min
Additive gas name: Ethylene additive gas flow rate: 20cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative permittivity: 2.67
Young's modulus: 4.5 GPa
Deposition: 40 nm / min

Example 12
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 26cc / min
Additive gas name: Ethylene additive gas flow rate: 24cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative permittivity: 2.61
Young's modulus: 4.5 GPa
Deposition: 40 nm / min

Example 13
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Ethylene base gas Flow rate: 30cc / min
Additive gas name: Helium additive gas flow rate: 20cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative dielectric constant: 2.54
Young's modulus: 4.5 GPa
Deposition: 40 nm / min

List of Examples 1, 9, and 11-13 Deposition by He / C ₂ H ₄ mixing and change in dielectric constant Common items Insulating film material name: Tetravinylsilane Insulating film material flow rate: 25 cc / min
Base gas name: Helium Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C

Example 14
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Ethylene base gas Flow rate: 30cc / min
Additive gas name: Helium additive gas flow rate: 15cc / min
Additive gas name: Hydrogenated gas flow rate: 5cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative permittivity: 2.53
Young's modulus: 4.9 GPa
Deposition: 40 nm / min

Example 15
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 30cc / min
Additive gas name: Ethylene additive gas flow rate: 15cc / min
Additive gas name: Hydrogenated gas flow rate: 5cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative permittivity: 2.66
Young's modulus: 4.9 GPa
Deposition: 40 nm / min

Example 16
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Hydrogen base gas Flow rate: 50cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Relative permittivity: 2.75
Young's modulus: 11.2 GPa
Deposition: 40 nm / min

Example 17
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: 7 torr
RF power: 100 W → 200 W Substrate temperature changed as shown in the graph of FIG. 4: 350 ° C.
After the elapsed time of 1, 5, 6, 7, and 12 minutes, the film formation was interrupted, and the density and relative dielectric constant of each formed film were measured.
The results are shown in FIG.

Example 18
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: RF power changed from 7 torr to 1 torr as shown in the graph of FIG. 6: Substrate temperature changed from 100 W to 200 W as shown in the graph of FIG. 6: 350 ° C.
After the elapsed time 1, 5, 6, 7, 8, 9, 10, 12, 13, 15 minutes, the film formation was interrupted, and the density and relative dielectric constant of each film formed were measured.
The results are shown in FIG.

Example 19
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas Flow rate: Pressure changed from 50 cc / min to 60 cc / min as shown in the graph of FIG. 8: 7 torr
RF power: substrate temperature changed from 100 W to 200 W as shown in the graph of FIG. 8: 350 ° C.
After the elapsed time of 1, 5, 6, 7, 9, 10, and 15 minutes, the film formation was interrupted, and the density and relative dielectric constant of each formed film were measured.
The results are shown in FIG.

Example 20
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 50cc / min
Pressure: RF power changed from 7 torr to 1 torr as shown in the graph of FIG. 10: 100 W
Substrate temperature: 350 ° C
After the elapsed time of 1, 5, 6, 7, 8, 9, 10, and 15 minutes, the film formation was interrupted, and the density and relative dielectric constant of each formed film were measured.
The results are shown in FIG.

Example 21
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas Flow rate: Pressure changed from 50 cc / min to 60 cc / min as shown in the graph of FIG. 12: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
After the elapsed time of 1, 5, 6, 7, and 12 minutes, the film formation was interrupted, and the density and relative dielectric constant of each formed film were measured.
The results are shown in FIG.

Example 22
Insulating film material name: Tetravinylsilane insulating film material Flow rate: 25 cc / min
Base gas name: Helium base gas flow rate: 40cc / min
Porogen: cyclohexane oxide porogen flow rate: 10 cc / min
Pressure: 7 torr
RF power: 100W
Substrate temperature: 350 ° C
Annealing pressure: 1 torr
Annealing atmosphere: N ₂
Annealing temperature: 400 ° C
Annealing time: 30 min
Relative dielectric constant: 2.32
Young's modulus: 3.6 GPa

It is a graph which shows the relationship between the Young's modulus and dielectric constant about the internal structure model of an insulating film. It is a graph which shows the infrared spectroscopy spectrum of 2 types of insulating films by the strength of the high frequency electric power for plasma generation. It is a schematic block diagram which shows the example of the plasma film-forming apparatus used by this invention. 18 is a graph showing changes in film forming conditions in Example 17. 18 is a graph showing changes in dielectric constant and density of an insulating film accompanying changes in film formation conditions in Example 17. 18 is a graph showing changes in film forming conditions in Example 18. 19 is a graph showing changes in dielectric constant and density of an insulating film accompanying changes in film forming conditions in Example 18. 14 is a graph showing changes in film forming conditions in Example 19. 42 is a graph showing changes in dielectric constant and density of an insulating film accompanying changes in film formation conditions in Example 19. 22 is a graph showing changes in film forming conditions in Example 20. 22 is a graph showing changes in dielectric constant and density of an insulating film accompanying changes in film forming conditions in Example 20. 22 is a graph showing changes in film forming conditions in Example 21. 22 is a graph showing changes in dielectric constant and density of an insulating film accompanying changes in film formation conditions in Example 21.

Claims (10)

An insulating film material for plasma CVD, represented by the following chemical formula (1), wherein the obtained insulating film is composed only of silicon, carbon, and hydrogen.

  A film forming method for forming an insulating film made of only silicon, carbon and hydrogen by plasma CVD using the insulating film material according to claim 1.   The film forming method according to claim 2, wherein the film formation is performed with at least one kind of chain hydrocarbon having 2 to 3 carbon atoms.   The film forming method according to claim 3, further comprising depositing at least one of helium, xenon, argon, krypton, and hydrogen.   The film-forming method according to claim 3 or 4, wherein the chain hydrocarbon having 2 to 3 carbon atoms contains an unsaturated bond.   6. The film formation according to claim 2, wherein the film formation is performed while changing at least one of a high frequency power for plasma generation, a flow rate of a film formation gas, and a film formation pressure during the film formation by the plasma CVD method. Method.   7. The film forming method according to claim 2, wherein a film is formed by adding porodiene during film formation.   An insulating film obtained by the film forming method according to claim 2.   The insulating film according to claim 8, wherein the dielectric constant changes in the thickness direction.   The insulating film according to claim 8, wherein the density changes in the thickness direction.

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