JP3428927B2 - Dry etching method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry etching method for an organic low dielectric constant insulating film used for an interlayer insulating film of a semiconductor device, and more particularly to a high precision processing of the organic low dielectric constant insulating film. The present invention relates to a dry etching method which is high in quality and can be processed without deterioration of film quality and defective filling of metal wiring.

[0002]

2. Description of the Related Art A conventional organic low dielectric constant insulating film etching process will be described with reference to FIG. In FIG. 2, 2
01 is a resist mask, 202 is a silicon oxide film, 20
3 is an organic low dielectric constant insulating film, 204 is a metal wiring, 205 is a wiring groove or a via hole, and 206 is a side wall protective film.

Since the organic low dielectric constant insulating film alone has problems in hygroscopicity, mechanical strength, plasma resistance, etc., generally, as shown in FIG. 2, a silicon oxide film or the like formed by plasma CVD is formed thereon. Cover and use. When forming a wiring groove or a via hole having a damascene structure in this film, the following procedure is performed.

First, as shown in FIG. 2A, after forming a resist mask for forming a groove or a hole, the upper silicon oxide film is etched (FIG. 2B), and then the organic layer is formed. Etching of low dielectric constant insulating film (Fig. 2
(C)). The etching of the upper silicon oxide film is performed using a fluorocarbon-based gas (for example, C ₄ F ₈ / CO / Ar / O ₂ -based gas) which has been generally used conventionally.

The organic low dielectric constant insulating film can be generally etched by oxygen plasma. For example, as disclosed in Japanese Patent Laid-Open No. 8-316209, O
Most organic low dielectric constant insulating films can be easily etched at a high etching rate by using plasma of ₂ and CO ₂ gas. However, Proceedings of the 59th JSAP Academic Lecture (Autumn 1998) 15p-C-
As described in 10, the organic substance reacts not only with oxygen ions but also with oxygen radicals, and the etching proceeds isotropically. Therefore, the sectional shape of the hole or groove is as shown in FIG. 2 (c). It tends to have a barrel shape, which is the so-called Boeing shape. With such a shape, in a subsequent wiring metal film forming step, a metal filling failure occurs inside the hole or groove, which causes a failure such as an increase in wiring resistance and, in the worst case, a disconnection of the wiring.

As described above, when the protective film is not formed on the side wall of the organic low dielectric constant insulating film, no matter how the gas system or etching conditions are adjusted to ensure the vertical shape, the organic low dielectric constant is obtained. Oxygen radicals are generated due to oxygen existing in the insulating film, and the organic low dielectric constant insulating film is etched by the oxygen radicals, resulting in a bowing shape as shown in FIG. 2C. When the resist mask ashing step is performed after the organic low dielectric constant insulating film etching step, the organic low dielectric constant insulating film is further etched by oxygen radicals generated in plasma. From the above results, in the etching process of the organic low dielectric constant insulating film,
It can be said that the formation of a side wall protective film having plasma resistance is indispensable.

Further, as another disadvantage of etching by oxygen plasma, for example, Proceedin
gs of Symposium on Dry Pr
cess 1998 p. 175, there is a problem of deterioration of the film quality. That is, this is because the organic low dielectric constant insulating film exposed to oxygen plasma forms an altered layer in which oxygen is adsorbed or combined with oxygen, and this oxygen is used in the subsequent wiring metal forming step such as tungsten. This is a problem in that the plug is detached during the CVD process, resulting in defective filling in the hole or groove.

In order to solve the above problems, for example, as disclosed in Japanese Unexamined Patent Publication No. 10-189543, while processing SO ₂ gas with oxygen plasma, the side wall processed with sulfur is processed. A method of protecting and preventing deterioration of film quality has been proposed. However, even if this gas system is used, the deterioration of the film cannot be prevented, and the filling failure still occurs in the tungsten plug process.

As described above, in the etching of an organic low dielectric constant insulating film with an oxygen-based gas, deterioration of the film quality cannot be avoided in spite of the high etching rate, so that oxygen is not contained at all or a trace amount. Etching with a gas system containing only this is required.

An example of etching an organic low dielectric constant film with a gas other than oxygen is, for example, Japanese Patent Laid-Open No. 10-1501.
No. 05 publication discloses a fluorocarbon-based gas (for example, C ₄ F ₈ / CO / Ar /) used for etching SiO ₂ which has been widely and commonly used as an interlayer insulating film.
An example is disclosed in which the O ₂ -based gas) is applied as it is. However, only a fluorine-containing organic low-dielectric-constant insulating film (for example, a fluorinated polyaryl ether represented by the following general formula (1)) can be etched at high speed with a fluorocarbon-based gas, and does not contain fluorine. Since the etching rate of an organic low dielectric constant insulating film (for example, polyaryl ether represented by the following general formula (2)) is about 1/10 of that containing fluorine, it should be applied to actual semiconductor production. I couldn't.

[0011]

[Chemical 1]

[0012]

[Chemical 2]

As another example of a gas system other than oxygen,
Proceedings of Symposium
on Dry Process 1998 p. 175
Discloses an example using a gas of H ₂ / N ₂ system (including NH ₃ ). However, with the H ₂ / N ₂ system, there is no problem in terms of etching shape and film quality deterioration, but even with a high-density plasma device, it is very slow at 100 to 300 nm / min, so it is difficult to apply it to mass production. Met.

[0014]

As described above, there has been a problem that the deterioration of the film quality due to the adsorption of oxygen to the organic low dielectric constant insulating film cannot be avoided by the plasma using the oxygen-based gas.

Further, although the fluorine-containing organic low dielectric constant insulating film could be etched at a high speed with the fluorocarbon gas, the fluorine-free organic low dielectric constant insulating film was sufficiently etched for mass production. There was a problem that I could not get the speed.

Further, with the H ₂ / N ₂ system gas, although there is no problem in etching shape and film quality deterioration, there is a problem that the etching rate is very slow.

Further, in the etching process of the organic low dielectric constant insulating film, if the side surface of the organic low dielectric constant insulating film is not covered with the protective film, the organic low dielectric constant insulating film itself is etched, and this occurs. There is a problem that the shape is destroyed by oxygen radicals or oxygen radicals generated in the ashing process.

Therefore, in order to solve the conventional problems, in order to prevent the deterioration of the film quality of the organic low dielectric constant insulating film, a gas system containing no oxygen is adopted to form a strong side wall protective film, and It was necessary to find a gas system and an etching device that can obtain an etching rate sufficient for mass production.

An object of the present invention is to provide a dry etching method which has a good etching shape, does not deteriorate the quality of the organic low dielectric constant insulating film, and has a high etching rate.

[0020]

According to the present invention, in a dry etching method of a laminated film including an organic low dielectric constant insulating film formed as an interlayer insulating film, a gas and hydrocarbon which easily release fluorine as an etching gas. Gas and
Alternatively, a gas that easily releases fluorine, a hydrocarbon gas, and a rare gas are introduced into a vacuum container in which a semiconductor substrate is installed, and high-frequency power is applied to plasma generation means to generate plasma, and the plasma is used. A dry etching method for etching an organic low dielectric constant insulating film formed on a surface of a semiconductor substrate is provided.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

The dry etching method of the present invention will be described with reference to FIG. In FIG. 1, 101 is a resist mask, 102 is a silicon oxide film, 103 is an organic low dielectric constant insulating film, 104 is a metal wiring, 105 is a wiring groove or via hole, and 106 is a side wall protective film.

For the organic low dielectric constant insulating film, for example, a material having the structural formula shown in the general formula (1) or the general formula (2) is used. The film structure is exactly the same as that of the conventional example shown in FIG. 2, and since the organic low dielectric constant insulating film alone has problems in hygroscopicity, mechanical strength, plasma resistance, etc. Cover with a film and use. The step of forming a wiring groove or via hole having a damascene structure in this film is also the same as in the conventional example of FIG. 2, and is performed by the following procedure.

First, as shown in FIG. 1 (a), after forming a resist mask for forming a groove or a hole, the upper silicon oxide film is etched (FIG. 1 (b)), and then an organic layer is formed. Etching of low dielectric constant insulating film (Fig. 1
(C)). The etching of the upper silicon oxide film is performed using a fluorocarbon-based gas (for example, C ₄ F ₈ / CO / Ar / O ₂ -based gas) which has been generally used conventionally.

The gas used in the dry etching method for an organic low dielectric constant insulating film according to the present invention is a gas and a hydrocarbon gas that easily release fluorine, or a gas and a hydrocarbon that easily release fluorine. Gas and noble gas.

The above-mentioned gas was introduced into a vacuum vessel, and high frequency electricity was applied.
When a plasma is generated by applying a force, in the plasma,
Fluorine ion, radical and CH_XIon, radical, water
Elemental, HF ions, radicals, etc. are generated. these
Of these, fluorine ions, radicals and hydrogen ions
By entering the semiconductor substrate with the exposed insulating film,
The charcoal that is a constituent element of the organic low dielectric constant insulating film
Elemental, nitrogen, hydrogen, oxygen, and fluorine are, for example, CH_XF_Y, N
H_XF_Y, CN, H₂, H₂Volatile in the form of O, HF,
The etching reaction proceeds. On the other hand, there is no ion injection.
On the side of the turn, CH _XRadicals attach and polymerize,
A hydrocarbon-based polymer film containing nitrogen is produced.

The reaction between the fluorine radical and the organic low dielectric constant insulating film occurs slightly without ion assist. Therefore, in order to keep the etching shape vertical, a strong polymer film on the side surface of the pattern should be formed. Formation is essential.
Further, in order to suppress the spontaneous reaction between the above-mentioned fluorine radicals and the organic low dielectric constant insulating film and make it difficult for the shape to collapse, it is desirable to cool the temperature of the substrate. Although there is no problem in the range of the substrate temperature as long as it is room temperature or lower, by cooling it to 0 ° C. or lower, lateral etching is suppressed even with a thinner side wall protective film, and a more vertical etching shape can be obtained. . However, if the plasma condition is kept constant and only the substrate temperature is lowered, the side wall film becomes thicker and the hole diameter becomes thinner at the bottom of the hole.Therefore, when the temperature is changed, the optimum process is performed each time. It is necessary to find the conditions.

Although FIG. 1 shows an example in which only the upper layer of the organic low dielectric constant insulating film is covered with the silicon oxide film, a structure in which the upper and lower sides of the organic low dielectric constant insulating film are sandwiched by the silicon oxide films can be considered. . In this case, it is necessary to etch the lower silicon oxide film after etching the organic low dielectric constant insulating film. At this time, if side wall protection is performed during the etching of the organic low dielectric constant insulating film, even in the subsequent step of etching the lower layer silicon oxide with a fluorocarbon-based gas, the organic lowering due to oxygen or fluorine radicals generated in plasma is performed. The dielectric constant insulating film is not etched, and a good etching shape can be obtained.

Examples of the gas that produces the minimum necessary fluorine ions and CH _x radicals for the above reaction include C
A gas such as HF ₃ is sufficient. However, considering that the etching rate and the composition of the sidewall protective film can be controlled by controlling the fluorine amount and the carbon amount of the source gas,
By adding a hydrocarbon gas to a gas that easily releases the amount of fluorine, the amount of fluorine and the amount of carbon can be controlled in a wider range, and the process window can be widened. As a gas that easily releases fluorine, for example, NF
₃ , SF ₆ , ClF ₃ , F _2, etc. are considered. Also, Plas
Gas that produces CH _x radicals and contains no oxygen
For example, CH ₄ , C ₂ H ₆ , C ₂ H ₄ , C ₂ H ₂ and
And C ₃ H ₆ etc., hydrocarbon gas is a single carbon bond.
Out of all compounds with double or triple bonds,
A compound that is a gas or a liquid at room temperature is conceivable. Only
And what is actually available in the plasma process is
Limited to compounds that are gases or liquids in the environment in which the body is manufactured
To be done.

Further, for example, He, Ne, A is added to the above gas system.
By adding a rare gas such as r, Kr, Xe, and Rn, it is expected that the plasma density will be improved and the sputtering efficiency by ions will also be improved, so that a higher etching rate can be obtained.

The plasma processing apparatus used in the dry etching method of the present invention uses a plasma having a density as high as possible from the viewpoint of ensuring a sufficiently high etching rate even in a gas having a low reactivity such as hydrogen or nitrogen. It is desirable that the plasma processing apparatus can generate plasma. Examples of the plasma processing apparatus preferably used in the present invention include an ECR type plasma processing apparatus, a helicon wave type plasma processing apparatus, an ICP type plasma processing apparatus, and a SWP.
Type plasma processing apparatus, SIP type plasma processing apparatus and the like, but the present invention is not limited to the plasma apparatus and is a plasma apparatus capable of generating high density plasma of 1 × 10 ¹¹ cm ⁻³ or more. Any device can be applied as long as it is provided.

[0032]

EXAMPLES Hereinafter, the dry etching method of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 As a first example of the present invention, the results of etching an organic low dielectric constant film using SF ₆ gas and CH ₄ gas will be shown. In this embodiment,
Etching was performed using an ECR type plasma etching device. In addition, a series of etching processes for the stacked interlayer insulating films were all performed in the same processing chamber.

First, a silicon substrate having the sectional structure shown in FIG. 1A was prepared. Here, the upper silicon oxide film 102 is formed of plasma TEOS SiO _{2 having a} film thickness of 200 nm.
The film, the organic low dielectric constant insulating film 103, is a spin-coated film having a thickness of 8
00 nm polyaryl ether, metal wiring 104 is a 500 nm thick Al-Cu film, and the base is plasma TE.
This is a structure of OS SiO ₂ 1 μm / Si substrate (not shown). This wafer was placed on the substrate support of an ECR type plasma etching apparatus, and a turbo molecular pump was used to
The inside of the vacuum vessel was evacuated to a pressure of 1 × 10 ⁻⁶ Torr.

Next, plasma is generated under the following conditions,
The upper silicon oxide film was etched.

Gas type and flow rate: C ₄ F ₈ / CO / Ar / O ₂
= 14/140/180/5 sccm Pressure: 35 mTorr Substrate temperature: -20 ° C. Magnetic field: 875 Gauss Microwave power: 800 W Substrate RF frequency, power: 13.56 MHz, 300 W

At this time, Vdc of the substrate support is about -180.
It was V. The above etching treatment was performed for 20 seconds to completely remove the upper silicon oxide film 102. The end point of the etching of the silicon oxide film was determined by a change in the emission intensity of SiF (wavelength 640 nm) using a plasma emission intensity monitor.

Next, after evacuating the vacuum vessel for 30 seconds,
Plasma was generated under the following conditions to etch the organic low dielectric constant insulating film.

Gas type, flow rate: SF ₆ / CH ₄ = 50/10 sccm Pressure: 10 mTorr Substrate temperature: −20 ° C. Magnetic field: 875 Gauss Microwave power: 800 W RF frequency, power: 13.56 MHz, 250 W

At this time, Vdc of the substrate support is about -110.
It was V. The above etching treatment was performed for 80 seconds to completely remove the organic low dielectric constant insulating film 103. The end point of the etching of the organic low dielectric constant insulating film was judged by the change in the emission intensity of F (wavelength 624 nm) using a plasma emission intensity monitor. The etching rate of the film calculated from the etching time was about 600 nm / min, which was a sufficiently high value.

After all the above processes were completed, the resist mask was removed, if necessary, and after the steps of cleaning and barrier metal film formation, tungsten plug film formation was carried out. The cross section of the wafer after film formation was observed by SEM, and it was confirmed that there was no shape abnormality such as bowing in the shape of the via hole and that tungsten was also normally embedded.

(Embodiment 2) As a second embodiment of the present invention, the results of etching an organic low dielectric constant film using SF ₆ gas and CH ₄ gas will be shown. In this embodiment,
Etching was performed using a SIP type plasma etching apparatus instead of the ECR type plasma etching apparatus. In addition, a series of etching treatments of the laminated interlayer insulating films are
All were performed in the same processing chamber.

First, a silicon substrate having a sectional structure similar to that of Example 1 was prepared. This wafer was placed on the substrate support of the SIP type plasma etching apparatus, and the inside of the vacuum container was evacuated by using a turbo molecular pump until the pressure became 1 × 10 ⁻⁶ Torr.

Next, plasma is generated under the following conditions,
The upper silicon oxide film was etched.

Gas type and flow rate: C ₄ F ₈ / Ar / O ₂ = 20
/ 150 / 5sccm Pressure: 30mTorr Substrate temperature: -20 ° C Microwave power: 1kW Substrate RF frequency, power: 13.56MHz, 250W

At this time, Vdc of the substrate support is about -120.
It was V. The above etching treatment was performed for 15 seconds to remove all the upper silicon oxide film 102. The end point of the etching of the silicon oxide film was determined by a change in the emission intensity of SiF (wavelength 640 nm) using a plasma emission intensity monitor.

Next, after evacuating the vacuum vessel for 30 seconds,
Plasma was generated under the following conditions to etch the organic low dielectric constant insulating film.

Gas type, flow rate: SF ₆ / CH ₄ = 50/10 sccm Pressure: 5 mTorr Substrate temperature: −20 ° C. Microwave power: 1 kW Substrate RF frequency, power: 13.56 MHz, 250 W

At this time, Vdc of the substrate support is about -100.
It was V. The above etching treatment was performed for 50 seconds to completely remove the organic low dielectric constant insulating film 103. The end point of the etching of the organic low dielectric constant insulating film was judged by the change in the emission intensity of F (wavelength 624 nm) using a plasma emission intensity monitor. The etching rate of the film calculated from the etching time was about 960 nm / min, which was a value sufficiently applicable to production.

After all the above processes were completed, the resist mask was removed, if necessary, and after the steps of cleaning and barrier metal film formation, a tungsten plug film was formed. The cross section of the wafer after film formation was observed by SEM, and it was confirmed that there was no shape abnormality such as bowing in the shape of the via hole and that tungsten was also normally embedded.

(Embodiment 3) As a third embodiment of the present invention, the result of etching an organic low dielectric constant film using NF ₃ gas and CH ₄ gas will be shown. In this embodiment,
As in Example 2, etching was performed using a SIP type plasma etching apparatus.

First, a silicon substrate having a sectional structure similar to that of Example 1 was prepared, and the upper silicon oxide film was etched in the same procedure as in Example 2.

Next, the organic low dielectric constant insulating film was etched under the following conditions.

Gas type, flow rate: NF ₃ / CH ₄ = 50/10 sccm Pressure: 5 mTorr Substrate temperature: −20 ° C. Microwave power: 1 kW Substrate RF frequency, power: 13.56 MHz, 250 W

At this time, Vdc of the substrate support is about -100.
It was V. The above etching treatment was performed for 53 seconds to completely remove the organic low dielectric constant insulating film 103. The etching rate of the film calculated from the etching time is about 905 nm /
It was min.

After the etching process was completed, the resist mask was removed as needed, and after the steps of cleaning and barrier metal film formation, a tungsten plug film was formed. The cross section of the wafer after film formation was observed by SEM. The shape of the via hole did not show any shape abnormality such as bowing.
It was also confirmed that tungsten was normally embedded.

(Embodiment 4) As a fourth embodiment of the present invention, the results of etching an organic low dielectric constant film using F ₂ gas and CH ₄ gas will be shown. Also in this example, as in Example 2, etching was performed using a SIP type plasma etching apparatus.

First, a silicon substrate having a sectional structure similar to that of Example 1 was prepared, and the upper silicon oxide film was etched in the same procedure as in Example 2.

Next, the organic low dielectric constant insulating film was etched under the following conditions.

Gas type, flow rate: F ₂ / CH ₄ = 40/10 sccm Pressure: 5 mTorr Substrate temperature: −20 ° C. Microwave power: 1 kW Substrate RF frequency, power: 13.56 MHz, 250 W

At this time, Vdc of the substrate support is about -105.
It was V. The above etching treatment was performed for 55 seconds to remove all the organic low dielectric constant insulating film 103. The etching rate of the film calculated from the etching time is about 870 nm /
It was min.

After the etching process was completed, the resist mask was removed if necessary, and after cleaning and barrier metal film formation steps, a tungsten plug film was formed. The cross section of the wafer after film formation was observed by SEM. The shape of the via hole did not show any shape abnormality such as bowing.
It was also confirmed that tungsten was normally embedded.

(Embodiment 5) As a fifth embodiment of the present invention, a result of etching an organic low dielectric constant film using F ₂ gas, C ₂ H ₆ gas and Ar gas will be shown. Also in this example, as in Example 2, etching was performed using a SIP type plasma etching apparatus.

First, a silicon substrate having a sectional structure similar to that of Example 1 was prepared, and the upper silicon oxide film was etched in the same procedure as in Example 2.

Next, the organic low dielectric constant insulating film was etched under the following conditions.

Gas type and flow rate: F ₂ / C ₂ H ₆ / Ar = 60
/ 10/100 sccm Pressure: 5 mTorr Substrate temperature: -20 ° C. Microwave power: 1 kW Substrate RF frequency, power: 13.56 MHz, 250 W

At this time, Vdc of the substrate support is about -105.
It was V. The above etching treatment was performed for 65 seconds to completely remove the organic low dielectric constant insulating film 103. The etching rate of the film calculated from the etching time is about 740 nm /
It was min. Further, the resist mask was completely removed after the etching of the organic low dielectric constant insulating film was completed.

After completion of all etching processes, cleaning,
After the barrier metal film formation process, a tungsten plug film was formed. The cross section of the wafer after film formation was observed by SEM, and it was confirmed that there was no shape abnormality such as bowing in the shape of the via hole and that tungsten was also normally embedded.

[0069]

As described above, according to the present invention, when etching an organic low dielectric constant insulating film, a gas that easily releases fluorine and a hydrocarbon gas as an etching gas, or fluorine is easily added. By using the liberated gas, the hydrocarbon gas and the rare gas, it is possible to provide a dry etching method which has a good etching shape, does not deteriorate the quality of the organic low dielectric constant insulating film, and has a high etching rate. became.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a method for etching an organic low dielectric constant insulating film according to the present invention.

FIG. 2 is a schematic view showing a method for etching an organic low dielectric constant insulating film in the prior art.

[Explanation of symbols]

101,201 resist mask 102,202 Upper silicon oxide film 103,203 Organic low dielectric constant insulating film 104,204 Lower silicon oxide film 105,205 Wiring groove or via hole 106,206 Side wall protection film

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-268526 (JP, A) JP-A-10-256240 (JP, A) JP-A-8-17928 (JP, A) JP-A-2000-340549 (JP, A) Japanese Patent Publication Sho 61-58975 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/3065 H01L 21/3213 H01L 21/768

Claims (13)

(57) [Claims] 1. A dry etching method for a laminated film including an organic low dielectric constant insulating film formed as an interlayer insulating film, wherein a gas that easily releases fluorine and a hydrocarbon gas are used.
The semiconductor substrate is introduced into a vacuum container in which it is installed, high-frequency power is applied to the plasma generating means to generate plasma, and the plasma is used to etch the organic low dielectric constant insulating film formed on the surface of the semiconductor substrate. A dry etching method characterized by the above. 2. The dry etching method according to claim 1, wherein the gas that easily releases fluorine and the hydrocarbon gas have a molecular structure containing no oxygen atom. 3. The gas that easily releases fluorine is N
F₃, SF₆, ClF ₃And F₂Single gas or multiple
The dry etchant according to claim 1 or 2, which is a mixed gas.
How to go. 4. The hydrocarbon gas is a carbon single bond,
The dry etching method according to any one of claims 1 to 3, which is a compound which is a gas or a liquid at room temperature among all compounds having a double bond or a triple bond. 5. The dry according to claim 1, wherein the plasma generation means is an ECR type plasma source, a helicon wave type plasma source, an ICP type plasma source, a SWP type plasma source or a SIP type plasma source. Etching method. 6. The dry etching method according to claim 1, wherein the organic low dielectric constant insulating film is a polyaryl ether or a fluorinated polyaryl ether. 7. A dry etching method for a laminated film including an organic low dielectric constant insulating film formed as an interlayer insulating film, wherein a gas easily releasing fluorine, a hydrocarbon gas and a rare gas are provided on a semiconductor substrate. It is characterized in that the organic low dielectric constant insulating film formed on the surface of the semiconductor substrate is etched by introducing into the vacuum container, applying high-frequency power to the plasma generating means to generate plasma. Dry etching method. 8. The dry etching method according to claim 7, wherein the gas that easily releases fluorine and the hydrocarbon gas have a molecular structure containing no oxygen atom. 9. The rare gas is He, Ne, Ar or K.
9. The dry etching method according to claim 7, which is a single gas or a mixed gas of a plurality of r, Xe, and Rn. 10. The gas that easily releases fluorine is
10. The dry etching method according to claim 7, which is a single gas or a mixed gas of a plurality of NF ₃ , SF ₆ , ClF ₃ and F ₂ . 11. The hydrocarbon gas, among all compounds having a single bond, double bond or triple bond of carbon,
A compound which is a gas or a liquid at room temperature and is a compound.
The dry etching method according to any one of 1. 12. The dry according to claim 7, wherein the plasma generating means is an ECR type plasma source, a helicon wave type plasma source, an ICP type plasma source, a SWP type plasma source or a SIP type plasma source. Etching method. 13. The dry etching method according to claim 7, wherein the organic low dielectric constant insulating film is a polyaryl ether or a fluorinated polyaryl ether.