JPH06232098A - Antioxidation and dry etching method - Google Patents

Abstract

PURPOSE:To improve the reliability of wiring formed by a film consisting of copper material by dry etching by preventing the film consisting of copper material from being oxidized from the formation of the film consisting of the copper material to that of an etching mask. CONSTITUTION:A film 21 consisting of copper material is formed on a substrate 11, the surface of the film 21 is covered with an organic film 22 which does not cause oxygen and water to pass, and an etching mask 23 is formed on the organic film 22. Also, the film 21 consisting of the copper material is formed, the etching mask is formed on the film 21, and furthermore at least the surface where the film 21 consisting of the copper material is exposed is covered with the organic film. Then, a gas consisting of at least either hydrogen or nitrogen or both of them or a gas which is obtained by mixing rare gas to the above gas is used as the etching gas for etching the organic film. After that, the film 21 consisting of the copper material is etched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antioxidation method for protecting a film made of a copper material from oxidation and a dry etching method after the antioxidation treatment in the manufacture of a semiconductor device.

[0002]

2. Description of the Related Art As semiconductor devices such as VLSI and ULSI have become more highly integrated and have higher performance in recent years, the design rule of metal wiring has been further miniaturized to the level of submicron or quarter micron. Conventionally, the metal wiring in a semiconductor device is mainly made of an aluminum-based material. However, in the wiring made of an aluminum-based material, if the design rule becomes finer than about 0.5 μm, the reliability of the wiring deteriorates due to occurrence of electromigration or the like. At the same time, the height of the wiring is increased due to the necessity of lowering the resistance value. Therefore, it becomes difficult to carry out a series of film forming processes such as formation of an interlayer insulating film and formation of a flattening film after wiring formation.

Therefore, attention has been paid to metal wiring made of a copper-based material. Copper has a high electromigration resistance and a low electric resistivity of about 1.4 μΩ, which is about half that of an aluminum-based material. Therefore, the metal wiring layer can be thinned without impairing reliability.

However, the etching technique for copper-based materials has not been fully established. The conventionally used aluminum-based material has a lower free energy for oxide formation than the copper-based material, but forms an extremely stable aluminum oxide film on the surface. However, in the case of a copper-based material, it is easily oxidized, and since a stable oxide film is not formed on the surface,
The oxygen adsorbed on the surface diffuses inside the copper-based material and oxidizes the copper of the copper-based material. When copper is oxidized, its electrical resistance increases, so copper oxide cannot be used for wiring.

Therefore, in order to protect the copper-based material from oxidation, after the etching of the copper-based material is completed, the surface of the copper-based material is coated with an antioxidant film without being exposed to an oxidizing atmosphere such as the atmosphere. The technique is disclosed in JP-A-64-7115.
No. 1 is disclosed.

[0006]

However, in the technique disclosed above, it is possible to prevent copper (Cu) from being oxidized after the etching for forming the wiring is completed, but it is possible to prevent the copper (Cu) from being oxidized. After the film is formed, it is impossible to prevent the oxidation of the surface of the copper film until the etching mask is formed with, for example, a resist and etching is performed thereafter. For example, after the etching mask has been formed, when the standing time until the etching process is long, a copper oxide film is formed on the exposed copper film surface, and oxygen diffuses inside the copper film. Therefore, there is a problem that the electrical resistance of the wiring formed of the copper film becomes high. At the same time, the reproducibility of etching deteriorates, so that highly accurate wiring cannot be formed.

According to the present invention, after a film made of a copper-based material is formed, a method for preventing oxidation of the film made of a copper-based material until the etching is performed and an oxidation preventing treatment is performed, and then the film made of a copper-based material is oxidized. It is an object of the present invention to provide a dry etching method for performing etching without performing the etching.

[0008]

The present invention is an oxidation preventing method and a dry etching method which are made to achieve the above object. That is, as an antioxidant method, after forming a film made of a copper-based material, a film made of a copper-based material is covered with, for example, an organic film impermeable to oxygen and moisture,
After that, an etching mask is formed on the organic film. The organic film is formed after forming a film made of a copper material without exposing the film made of a copper material to an oxidizing atmosphere. The organic film may contain a substance that absorbs the exposure wavelength.

Alternatively, after forming a film made of a copper-based material, an etching mask is formed on the film made of a copper-based material, and then at least the exposed surface of the film made of the copper-based material is exposed to, for example, oxygen and moisture. Cover with an organic film that does not pass through. Further, the etching mask and the organic film are formed without exposing the film made of the copper-based material to an oxidizing atmosphere.

The organic film is made of, for example, a polymer formed by plasma discharge. The gas used in this plasma discharge contains at least a halocarbon-based gas or a fluorocarbon-based gas and does not contain oxygen. Alternatively,
It contains at least a hydrocarbon-based gas and does not contain oxygen.

A dry etching method in which a film made of a copper-based material is covered with an organic film, an etching mask is formed, and dry etching is performed. When etching the organic film, at least hydrogen or nitrogen is used. A gas containing either one or both and containing neither halogen nor oxygen, or a mixed gas prepared by mixing a rare gas with a gas containing at least one or both of hydrogen and nitrogen and containing neither halogen nor oxygen, Etc. are used as the etching gas. Then, the exposed organic film is etched to expose the film made of the copper-based material, and then the film made of the copper-based material is etched.

Alternatively, a method of forming an etching mask on a film made of a copper-based material, covering at least the exposed film made of a copper-based material with an organic film, and then performing dry etching, is the same as the above. Using an etching gas, at least the organic film on the surface of the film made of a copper-based material is etched to expose the film made of the copper-based material excluding the portion covered by the etching mask, and then made of the copper-based material. Etch the film.

[0013]

In the above oxidation preventing method, at least the exposed film of the copper-based material is covered with the organic film, so that the film of the copper-based material is prevented from coming into contact with oxygen and moisture, so that the oxidation is prevented. To be prevented. Further, since the organic film is formed without exposing the film made of the copper material to the oxidizing atmosphere, no oxide film is formed on the surface of the film made of the copper material.

By forming the organic film from a film that does not pass oxygen and moisture, the film made of a copper-based material is not oxidized while being covered with the organic film. When an organic film containing a substance that absorbs the exposure wavelength is formed, halation that occurs when an etching mask made of, for example, a resist is formed on the organic film is prevented.

When the organic film is made of a polymer, the gas in the chamber in which the film made of a copper-based material is formed is replaced with a gas for producing a polymer, and plasma discharge treatment is performed so that the organic film is made of a copper-based material. An organic film made of a polymer is easily formed without exposing the film to an atmosphere having an oxidizing property. This plasma discharge contains at least a halocarbon-based gas or a fluorocarbon-based gas,
By using a gas containing no oxygen, or a gas containing at least a hydrocarbon-based gas and not containing oxygen, an organic film is formed without oxidizing the film made of a copper-based material.

When the organic film is dry-etched, an etching gas composed of at least one or both of hydrogen and nitrogen, or an etching gas obtained by mixing a rare gas with this gas is used. Contains neither oxygen nor halogen, so
The organic film is removed without oxidizing or corroding the film made of the copper-based material. By continuously etching the film made of the copper-based material, the pattern formed by the film made of the copper-based material is not oxidized and no oxide film is formed on the surface thereof. This means that after forming an etching mask on a film made of a copper-based material, etching of the organic film when the organic film is formed so as to cover at least the exposed film made of a copper-based material, The same applies to the etching of the film.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the method for preventing oxidation and dry etching of the present invention will be described with reference to the process chart of FIG. As shown in (1) of FIG. 1, a diffusion layer 12 is formed in a part of the upper layer of the silicon substrate 11. Further, an insulating film 13 made of silicon oxide is formed on the upper surface of the silicon substrate 11. The contact hole 1 is formed in the insulating film 13 on the diffusion layer 12.
4 are formed. A titanium (Ti) film 15 is usually formed as a contact metal film on the inner wall of the contact hole 14 and the surface of the insulating film 13, and titanium nitride oxide (TiO 2) is further formed as a barrier metal.
N) The film 16 is formed.

First, in the first step, for example, a copper (Cu) film 21 as a film made of a copper-based material is formed on the titanium nitride oxide film 16 including the inside of the contact hole 14. The copper film 21 is formed, for example, by sputtering or CV.
It is formed by the D method (chemical vapor deposition method) or the like.

Next, the second step (2) of FIG. 1 is performed.
In this step, the organic film 22 is formed in a state of covering the copper film 21 by, for example, a normal coating technique. The organic film 22 is made of, for example, a novolac-based resist film that is impermeable to oxygen and moisture, and has a film thickness of, for example, 100 n.
m. Then, the baking process is performed in a high temperature atmosphere. The baking temperature is the organic film 2 made of resist.
The temperature is set to such a degree that the surface of No. 2 does not exist (eg, 180 ° C.).

By using the organic film 22 to which a substance that absorbs the exposure wavelength in the exposure step described later is added, halation in the exposure step can be prevented. The substance that absorbs the exposure wavelength is, for example, a dye. As the dye, for example, curcumin, coumarin or the like can be used. further,
Although the organic film 22 described above is made of a novolac resist, it may be formed of, for example, a fluorine resin, a chlorine resin, or another resin as long as it is a resin impermeable to oxygen and moisture.

Subsequently, the third step (3) of FIG. 1 is performed.
In this step, an etching mask 23 made of, for example, a resist is formed on the organic film 22 by performing a normal resist coating step, a photosensitizing step, and a developing step. This etching mask is formed to have a film thickness of, for example, about 1.0 μm. Further, when a substance that absorbs the exposure wavelength is added to the organic film 22, halation caused by light rays reflected on the surface of the film made of a copper-based material in the above-mentioned exposure step is prevented.

Thereafter, a fourth step shown in FIG. 1 (4) is performed. In this step, the organic film 22 in the portion indicated by the chain double-dashed line is etched by, for example, microwave plasma etching. As an etching gas for etching the organic film 22, for example, nitrogen (N ₂ ) gas is used as an etching gas composed of at least one or both of nitrogen and hydrogen. Then, the pressure of the etching atmosphere is set to 2 Pa, for example. Further, the microwave power is set to 300 mA, and the RF bias output is set to 10 W, for example.

In the dry etching under the above conditions, the exposed organic film 22 is entirely etched by nitrogen ions generated by discharge decomposition. At that time, the surface of the etching mask 23 made of a resist is also etched, but the etching mask 23 is not the organic film 22.
Since it has a sufficient thickness with respect to
The function of 1 as an etching mask is not lost. Then, the organic film 22 is etched by the above etching, and the underlying copper film 21 is exposed. The copper film 21 is not etched by the nitrogen plasma generated at this time. Therefore, even if the film thickness of the organic film 22 varies to some extent, the organic film 22 on the copper film 21 can be completely removed by performing overetching. Further, since the etching gas does not contain oxygen or halogen, the copper film 21 is not oxidized or corroded during etching.

Then, following the etching of the organic film 22, the copper film 21 in the portion indicated by the alternate long and short dash line is etched. The etching conditions for the copper film 21 are, for example, chlorine (Cl ₂ ) having a flow rate of 100 sccm for the etching gas.
And a mixed gas of nitrogen (N ₂ ) with a flow rate of 20 sccm is used. The pressure of the etching atmosphere is set to 1.1 P, for example.
a, microwave power is set to 300 mA, RF bias output is set to 30 W, and substrate temperature is set to 250 ° C., for example. When the copper film 21 is etched under the above conditions, the organic film 22 is removed in advance, so the etching of the copper film 21 is substantially uniform over the entire exposed surface of the copper film 22. Starting with the desired copper film 21
The pattern 31 is formed. The copper film 2
In the etching of No. 1, the titanium film 15 and the titanium oxynitride film 16 in the portion shown by the broken line are also removed.

In the first embodiment, the copper film 21 is formed immediately after the copper film 21 is formed until immediately before the copper film 21 is etched.
Can be covered with the organic film 22, so that at least the copper film 21 is not oxidized until it is etched.

The etching gas used for dry etching the organic film 22 is, in addition to the above-described gas (nitrogen), for example, an etching gas composed of at least one or both of nitrogen and hydrogen,
It is also possible to use hydrogen (H ₂ ) gas.

When etching is performed using hydrogen gas, for example, even if the surface of the copper film 21 is oxidized or oxygen is adsorbed on the surface of the copper film 21, the strong reducing property of hydrogen gas is reduced. This removes oxygen forming oxides and oxygen adsorbed on the surface. Further, since the etching gas contains neither oxygen nor halogen,
The copper film 21 is not oxidized during the etching.

However, since hydrogen has a high risk of exploding, it must be handled with care. Therefore,
It is possible to use, for example, an ammonia (NH ₃ ) gas composed of hydrogen and nitrogen as a gas containing hydrogen atoms and having no risk of explosion and containing neither oxygen nor halogen.

Next, an example of etching the organic film 22 using ammonia gas will be described. As the etching gas, for example, ammonia gas having a flow rate of 50 sccm is used. Then, the pressure of the etching atmosphere is set to 2 Pa, for example. The microwave power is, for example, 300 mA,
The RF bias output is set to 10 W, for example.

In dry etching under the above conditions, nitrogen radicals, hydrogen radicals and their ionic species are generated by discharge decomposition. Then, the generated ions cause etching to proceed over the entire exposed surface of the organic film 22. At that time, the surface of the etching mask 23 made of a resist is also etched. However, since the etching mask 23 has a sufficient film thickness with respect to the organic film 22, it is possible to etch the copper film 21 thereafter. It does not lose its function as a mask.

Since hydrogen is more reactive than nitrogen, the etching rate of the organic film 22 is increased and the throughput is improved. Further, due to the high reducing property of hydrogen, even if the surface of the copper film 21 is oxidized, the oxidized portion is reduced. Therefore, the oxide is eliminated and the oxygen adsorbed on the surface of the copper film 21 is also removed. Then, at least the organic film 22 on the copper film 21 is removed, and the underlying copper film 21 is exposed. More continuously,
The copper film 21 is etched under the same etching conditions as the copper film 21 described above.

There is also a method of stabilizing discharge during etching of the organic film 22 to improve etching uniformity. That is, one or more kinds of gases composed of either or both of hydrogen and nitrogen, such as nitrogen (N ₂ ), hydrogen (H ₂ ), and ammonia (NH ₃ ), and a rare gas [eg, helium. (He), Argon (A
r), one or more of neon (Ne) and the like] is used as an etching gas.

For example, an example of etching the organic film 22 by using a mixed gas of ammonia (NH ₃ ) gas and argon (Ar) gas as an etching gas will be described. As the etching gas, a mixed gas of ammonia gas having a flow rate of 50 sccm and argon gas having a flow rate of 30 sccm is used. Then, the pressure of the etching atmosphere is set to 2 Pa, for example. Further, the microwave power is set to 300 mA, and the RF bias output is set to 10 W, for example.

In the dry etching under the above conditions, since the etching gas is mixed with the argon gas having a relatively low ionization potential, the plasma discharge becomes stable. Therefore, the density of the generated plasma becomes uniform, and the etching uniformity is improved. Since the reaction at the time of etching is almost the same as that when no rare gas is mixed, detailed description thereof is omitted here. In this way, at least the organic film 22 on the copper film 21 is etched to expose the underlying copper film 21. Then, successively, the copper film 21 is etched under the same etching conditions as described above for the copper film 21 to form a pattern 31 on the copper film 21.

Next, another oxidation preventing method will be described as a second embodiment with reference to the process chart of FIG. The same components as those in FIG. 1 are designated by the same reference numerals. Further, a dry etching method after forming the oxidation preventing organic film will be described.

As shown in FIG. 2A, a diffusion layer 12 is formed on a part of the upper layer of the silicon substrate 11. Further, an insulating film 13 made of silicon oxide is formed on the upper surface of the silicon substrate 11. The diffusion layer 1
A contact hole 14 is formed in the insulating film 13 on the upper part 2. A contact metal such as a titanium (Ti) film 15 and a barrier metal such as a titanium nitride oxide (TiON) film 16 are usually formed on the inner wall of the contact hole 14 and the surface of the insulating film 13.

First, in the first step, in the same manner as described in the first embodiment, a film made of a copper-based material, for example, copper, is formed on the titanium nitride oxide film 16 including the inside of the contact hole 14. A (Cu) film 21 is formed. The copper film 21 is formed by, for example, a sputtering method or a CVD method (chemical vapor deposition method).

Then, the second step shown in FIG. 2B is performed. In this step, the copper film 21 is covered with the organic film 24 by using, for example, a normal downflow type microwave plasma etching apparatus. The organic film 24 is made of, for example, a fluorocarbon polymer that is impermeable to oxygen and moisture.

Next, an example of conditions for producing the fluorocarbon polymer will be described. As the generation condition, for example, trifluoromethane (CHF ₃ ) having a flow rate of 80 sccm is used as the generated gas. The pressure of the generated atmosphere is set to 106 Pa, and the microwave current of the downflow type microwave plasma etching apparatus is set to 400 mA, for example. Further, the temperature of the stage on which the substrate 11 is placed is set to, for example, 3
The temperature is set to 0 ° C., and the deposition rate of the fluorocarbon polymer is set to, for example, about 100 nm / min. The deposition time is, for example, 15 seconds. Based on the above conditions, the film thickness is 25
An organic film 24 of about nm is formed.

Although trifluoromethane (CHF ₃ ) is used for depositing the fluorocarbon polymer, it is also possible to use, for example, a fluorocarbon gas whose molecule is composed of carbon, hydrogen and fluorine. Examples of the fluorocarbon gas include difluoromethane (CH ₂ F)
₂ ) or fluoromethane (CH ₃ F). Therefore, since the generated gas does not contain oxygen, the copper film 21 is not oxidized.

Subsequently, the third step shown in FIG. 2C is performed. In this step, in the same manner as described in the first embodiment, a normal resist coating step, exposure and development step are performed,
An etching mask 25 made of, for example, a resist is formed on the organic film 24. This etching mask is formed to have a film thickness of, for example, about 1.0 μm.

After that, a fourth step shown in FIG. 2D is performed. In this step, the organic film 24 in the portion indicated by the chain double-dashed line is etched in the same manner as described in the first embodiment. Then, preferably, the copper film 21 in the portion indicated by the alternate long and short dash line is removed by etching in the same manner as described in the first embodiment, and the pattern 31 is formed by the remaining copper film (21). In the etching of the copper film 21, the titanium film 15 and the titanium oxynitride film 16 in the part shown by the broken line are also removed.

In the second embodiment, the copper film 21 is formed immediately after the copper film 21 is formed until immediately before the copper film 21 is etched.
Can be covered with the organic film 24, so that at least the copper film 21 is not oxidized until it is etched.

Although the organic film 24 is formed of a fluorocarbon polymer, it may be formed of a hydrocarbon polymer, for example. In this case, for example, tetrafluoromethane (C
F ₄ ) or tetrafluoroethane (C ₂ F ₄ ),
A hydrocarbon-based gas composed of carbon and hydrogen may be used. Also in this case, since the generated gas does not contain oxygen, the copper film 21 is not oxidized.

Further, in the method of forming the organic film 24 by plasma discharge, since the polymer is formed almost uniformly on the film forming surface, the coverage at the step portion (not shown) becomes high. Further, it is possible to control the film thickness with high accuracy.

Further, in the second embodiment, for example, a CVD apparatus (or a sputtering apparatus, which forms the copper film 21),
After forming the copper film 21, the copper film 21 is exposed to an oxidizing atmosphere such as the atmosphere by using a so-called multi-chamber type device in which an evaporation device) and an etching device for forming the organic film 24 are combined. It becomes possible to form the organic film 24 without the need. Alternatively, the inside of the chamber of the CVD device (or the sputtering device or the vapor deposition device) for forming the copper film 21 may be set to a plasma atmosphere for generating a polymer, and the organic film 24 may be formed. As described above, by continuously forming the copper film 21 and the organic film 24, the copper film 21 is prevented from being oxidized or corroded at least until it is etched.

Next, an oxidation prevention method of forming an etching mask on the copper film and then an organic film for oxidation prevention and a dry etching method in this case will be described as a third embodiment with reference to the process chart of FIG. explain. The same components as those in FIG. 1 are designated by the same reference numerals.

As shown in FIG. 3A, a diffusion layer 12 is formed on a part of the upper layer of the silicon substrate 11. Further, an insulating film 13 made of silicon oxide is formed on the upper surface of the silicon substrate 11. The diffusion layer 1
A contact hole 14 is formed in the insulating film 13 on the upper part 2. Further, on the inner wall of the contact hole 14 and the surface of the insulating film 13, for example, a titanium (Ti) film 15 as a contact metal and a titanium nitride oxide (TiON) film 16 as a barrier metal are usually formed.

First, in the first step, in the same manner as described in the first embodiment, on the titanium nitride oxide film 16 including the inside of the contact hole 14, a film made of a copper-based material, such as copper, is used. A (Cu) film 21 is formed. The copper film 21 is formed by, for example, a sputtering method or a CVD method (chemical vapor deposition method).

Next, the second step of (2) in FIG. 3 is performed.
In this step, an etching mask 26 made of, for example, a resist is formed on the copper film 21 by performing a normal resist coating step, exposure and development steps. The etching mask 26 is formed to have a film thickness of, for example, about 1.0 μm.

Subsequently, the third step (3) of FIG. 3 is performed.
In this step, the exposed portion of the copper film 21 and the etching mask 26 are removed from the organic film 2 by using, for example, an ordinary downflow type microwave plasma etching apparatus.
Cover with 7. The organic film 27 is made of, for example, a fluorocarbon polymer that is impermeable to oxygen and moisture. Since the generation conditions at this time are the same as those described in the second embodiment, description thereof will be omitted here.

The product gas used for depositing the above fluorocarbon polymer is trifluoromethane (CH
In addition to F ₃ ), for example, difluoromethane (CH ₂ F ₂ )
Alternatively, it is also possible to use a fluorocarbon gas composed of carbon, hydrogen and fluorine, such as fluoromethane (CH ₃ F). Also in these cases, since the generated gas does not contain oxygen or halogen, the copper film 21 is neither oxidized nor corroded.

Alternatively, the organic film 27 can be formed of, for example, a hydrocarbon polymer. In this case, for example, tetrafluoromethane (CF ₄ ) or tetrafluoroethane (C ₂
A hydrocarbon-based gas composed of carbon and hydrogen such as F ₄ ) may be used. In these cases as well, since the generated gas contains neither oxygen nor halogen, the copper film 21 is neither oxidized nor corroded.

Thereafter, a fourth step shown in FIG. 3D is performed. In this step, the portion indicated by the chain double-dashed line of the organic film 27 is etched by, for example, microwave plasma etching. In this etching, for example, nitrogen (N ₂ ) gas is used. Since the etching conditions in this case are the same as those described in the first embodiment, detailed description thereof is omitted here. Alternatively, for example, hydrogen (H ₂ ) gas may be used as the etching gas. Alternatively, in order to stabilize discharge during etching and enhance etching uniformity, one or more kinds of gases such as nitrogen (N ₂ ), hydrogen (H ₂ ), ammonia (NH ₃ ) and a rare gas are used. It is also possible to use, as an etching gas, a mixed gas obtained by mixing [one or more kinds of helium (He), argon (Ar), etc.]. And copper film 2
In order to completely remove the organic film 27 on 1, the over etching is usually performed. At this time, since the surface layer of the etching mask 26 made of resist is also removed, the dimensions of the etching mask 26 may be designed in consideration of the amount of over-etching of the organic film 27.

Then, in succession to the above etching, the copper film 2
The portion indicated by the two-dot chain line 1 is etched. Since the etching conditions of the copper film 21 are the same as those described in the first embodiment, detailed description thereof will be omitted here. The copper film 2
In the etching of No. 1, the titanium film 15 and the titanium oxynitride film 16 in the portion shown by the broken line are also removed.

In the third embodiment, the copper film 21 can be covered with the organic film 27 immediately after the etching mask 26 is formed on the copper film 21 to immediately before the etching of the copper film 21. 21 is not oxidized at least after forming the etching mask 26 and before being etched. Further, in the above etching, since the organic film 27 is removed in advance, the etching is started almost uniformly over the entire surface of the exposed copper film 21. Therefore, the copper film 21 is etched with good uniformity.

In the third embodiment, for example, after the copper film 21 is formed, the etching mask 26 is formed in an inert atmosphere, and the organic film 27 is formed immediately after that, whereby the copper film 21 is formed. Almost no exposure to oxidizing atmosphere such as air. By continuously forming the etching mask 26 and the organic film 24 without exposing to the oxidizing atmosphere, the copper film 21 is prevented from being oxidized or corroded at least until it is etched.

Numerical values such as conditions and film thicknesses used in each of the above embodiments are not limited to those values, and can be appropriately changed depending on the manufacturing apparatus or the like.

[0059]

As described above, according to the oxidation preventing method of the present invention, oxygen and oxygen are formed on the copper-based material film after the copper-based material film is formed or after the etching mask is formed. Since the organic film impermeable to water is formed, it is possible to prevent the film made of the copper-based material from being oxidized until the film made of the copper-based material is etched. Therefore, the quality of a pattern such as a wiring formed of a film made of a copper-based material is improved, so that the electrical resistance of the wiring can be reduced, for example. In addition, the yield can be improved.

Further, when an organic film containing a substance that absorbs the exposure wavelength is formed, the effect of halation in the photosensitive process in forming the etching mask can be reduced, so that the etching mask can be used with high accuracy. Can be formed. Therefore, the dimensional accuracy of the pattern such as wiring can be improved. When the organic film is formed of polymer by plasma discharge, the coverage of the organic film on the step portion can be improved. In addition, since controllability of film formation is high, an organic film with high reliability can be formed. Furthermore, since it becomes possible to continuously form a film made of a copper-based material and an organic film, the film made of a copper-based material is less likely to be oxidized. Therefore, it is possible to improve the reliability of a pattern such as a wiring formed of a film made of a copper-based material.

Further, according to the dry etching method of the present invention, the organic film is etched using an etching gas composed of either or both of hydrogen and nitrogen, or a gas obtained by mixing a rare gas with the etching gas. Therefore, the film made of the copper-based material is not oxidized. Therefore, it is possible to form a highly reliable wiring with a film made of a copper-based material. When the etching gas contains hydrogen, the surface of the film made of the copper-based material is reduced by hydrogen. Therefore, the etching uniformity of the film made of the copper-based material can be improved, and the yield can be increased. Further, since the etching rate of the organic film is increased, the throughput can be improved. Further, when the etching gas contains a rare gas, a stable plasma discharge can be obtained, so that the etching uniformity is further improved. Therefore, the yield can be improved.

[Brief description of drawings]

FIG. 1 is a process drawing of a first embodiment.

FIG. 2 is a process drawing of a second embodiment.

FIG. 3 is a process drawing of a third embodiment.

[Explanation of symbols]

 11 Silicon Substrate 21 Copper Film 22 Organic Film 23 Etching Mask 24 Organic Film 25 Etching Mask 26 Etching Mask 27 Organic Film

Claims (11)

[Claims] 1. An antioxidation characterized by forming a film of a copper-based material on a substrate, coating the film of the copper-based material with an organic film, and then forming an etching mask on the organic film. Method. 2. The oxidation preventing method according to claim 1, wherein after the film made of the copper-based material is formed, the organic film is formed without exposing the film made of the copper-based material to an oxidizing atmosphere. A characteristic antioxidant method. 3. The antioxidant method according to claim 1 or 2, wherein the organic film contains a substance that absorbs at least an exposure wavelength. 4. A film made of a copper-based material is formed on a substrate, an etching mask is formed on the film made of the copper-based material, and then at least the exposed surface of the film made of the copper-based material is removed. A method for preventing oxidation, which comprises coating with an organic film. 5. The oxidation preventing method according to claim 4, wherein after forming the film made of the copper-based material, the etching mask is formed without exposing the film made of the copper-based material to an oxidizing atmosphere, An antioxidant method comprising forming an organic film. 6. Any one of claims 1 to 5.
Item 5. The antioxidant method according to Item 4, wherein the organic film is a film that is impermeable to oxygen and moisture. 7. Any one of claims 1 to 6
Item 5. The antioxidant method according to Item 4, wherein the organic film is made of a polymer formed by plasma discharge. 8. The antioxidant method according to claim 7, wherein the gas used in the plasma discharge contains at least a halocarbon-based gas or a fluorocarbon-based gas and does not contain oxygen. 9. The antioxidant method according to claim 7, wherein the gas used in the plasma discharge contains at least a hydrocarbon gas and does not contain oxygen. 10. A dry etching method in which a film made of a copper-based material is covered with an organic film, and then an etching mask is formed to perform dry etching, which is composed of at least one of hydrogen and / or nitrogen. Using an etching gas, or an etching gas formed by mixing a rare gas with at least one or both of hydrogen and nitrogen,
A dry etching method comprising: exposing the exposed organic film to expose a film made of the copper-based material, and then etching the film made of the copper-based material. 11. A dry etching method comprising forming an etching mask on a film made of a copper-based material, covering at least the exposed film made of a copper-based material with an organic film, and then performing dry etching. Using an etching gas composed of at least one or both of hydrogen and nitrogen, or an etching gas composed of a rare gas mixed with a gas composed of at least one or both of hydrogen and nitrogen,
By exposing the organic film on the surface of the film made of at least the copper-based material to expose the film made of the copper-based material excluding the portion covered by the etching mask, and then etching the film made of the copper-based material A dry etching method comprising: