JPH05291203A - Formation method of aluminum-based pattern - Google Patents

Abstract

PURPOSE:To enhance the selectivity in a dry etching operation of Al-based material layer. CONSTITUTION:An Al-based multilayer film 7 is etched by using a mixed gas of NOCl (nitrosyl chloride) and Cl2. At this time, a carbon-based polymer CClx which is formed as originated from the decomposition product of a resist mask 8 is endowed with a strong chemical bond and a strong electrostatic attraction force due to the introduction of a nitrosyl group (-N=O); its etchingresistant property is enhanced. Consequently, it is possible to reduce the energy of impinging ions required for an anisotropic working operation and the deposition amount of the carbon-based polymer; it is possible to enhance the selectivity of a resist and the selectivity of a substratum; in addition, it is possible to restrain a particle contamination and an aftercorrosion. The same effect can be obtained by using a mixed gas of NO2Cl (nitrile chloride) and Cl2. It is effective to perform a plasma cleaning operation by means of a fluorine-based gas after said etching operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an aluminum (Al) -based pattern which is applied in the field of semiconductor device manufacturing, etc., and particularly in dry etching of an Al-based material layer, improved resist selectivity and reduced particle contamination. , A method for suppressing after-corrosion.

[0002]

2. Description of the Related Art A material for electrode wiring of semiconductor devices is A
l, or an Al-Si alloy added with 1 to 2% of silicon (Si), and Al added with 0.5 to 1% of copper (Cu) as a measure against stress migration.
Al-based materials such as —Si—Cu alloys are widely used.

Dry etching of the Al-based material layer is generally performed using a chlorine-based gas. For example, BCl ₃ / Cl disclosed in JP-B-59-22374.
_A mixed gas is a typical example. The chemical species contributing as the main etching species in the etching of the Al-based material layer is C.
It is l ^* (chlorine radical), and promotes spontaneous and extremely rapid etching reaction. However, since etching proceeds isotropically only with Cl ^* , the ion-assisted reaction usually proceeds under conditions where the incident ion energy is increased to some extent, and the decomposition formation of the resist mask sputtered by the incident ions is generated. High selectivity is achieved by using the material as a sidewall protective film. BCl ₃ is Al
Is a compound added to reduce the natural oxide film on the surface of the system material layer, BCl _x as the incident ions
^It also plays an important role of supplying ⁺ .

[0004]

By the way, as described above, in order to secure the anisotropy, the incident ion
In the process of using energy to sputter a resist mask, a reduction in resist selectivity is necessarily a problem. The resist selectivity in a typical process is only about 2. Such low selectivity causes a dimensional conversion difference from the resist mask in the processing of a fine wiring pattern, and deteriorates the anisotropic shape.

On the other hand, under the design rules of highly miniaturized semiconductor devices, it is required to reduce the thickness of the resist coating film from the viewpoint of improving the resolution in photolithography. Therefore, it is becoming difficult to achieve both high resolution based on a thin resist coating film and high precision etching through a resist mask formed from this resist coating film.

In order to deal with this problem, a method of depositing a reaction product on the surface of a resist mask has been conventionally proposed. For example, the proceedings of the 33rd integrated circuit symposium lecture (1987), p. 114, a process using SiCl ₄ as an etching gas is reported. This aims to increase the etching resistance of the resist mask by coating the surface of the resist mask with Si.

[0007] Further, Proceedings of t
he 11th Symposium on Dry
Process, p. 45 (1989), BBr ₃
The process of using is reported. This aims to further enhance the etching resistance of the resist mask by coating the surface of the resist mask with CBr _x having a low vapor pressure. Regarding the protection mechanism of the resist mask by CBr _x, etc., monthly semiconductor world December 1990 issue, p103-10
7 (published by Press Journal), a value of about 5 is reported as a resist selection ratio.

However, in order to achieve the resist selection ratio at the above level, it is necessary to deposit Si and CBr _x in a considerably large amount, and there is a great possibility that the particle level is deteriorated in an actual manufacturing line. Therefore, an object of the present invention is to solve the above problems and provide a method for forming an Al-based pattern capable of achieving high resist selectivity while suppressing particle contamination.

[0009]

The method of forming an Al-based pattern of the present invention is proposed to achieve the above-mentioned object, and has at least one functional group of a nitrosyl group or a nitrile group in the molecule. It is characterized in that the Al-based material layer on the substrate is etched by using an etching gas containing a halogen compound having a halogen atom.

The invention is also characterized in that the etching gas further comprises a sulfur-based compound capable of releasing sulfur into the plasma under discharge dissociation conditions.

The present invention is further characterized in that after the etching of the Al-based material layer is completed, plasma processing is performed using a processing gas containing a fluorine-based compound while heating the substrate.

[0012]

The point of the present invention is that by strengthening the film quality of the carbon-based polymer itself, a sufficiently high resist selectivity can be achieved even if the deposition amount is reduced. As a method for enhancing the quality of the carbonaceous polymer itself, using a halogen compound having at least one functional group and the halogen atom in the present invention nitrosyl groups in the molecule (-N = O) or a nitrile group (-NO ₂₎ To do.

Since these compounds contain a halogen atom in the molecule, they can theoretically constitute the etching gas for the Al-based material layer alone. However, the important action of the halogen compound in the etching reaction system of the present invention is that each of the functional groups can have a structure in which the N atom is positively charged and the O atom is negatively charged, so that high polymerization acceleration is achieved. It is to have activity. That is, the presence of such a functional group or an atomic group derived from the functional group in the plasma increases the degree of polymerization of the carbon-based polymer, and can enhance the resistance to ion injection and radical attack. In addition, when the above-mentioned functional group is introduced into the carbon-based polymer, the chemical and physical stability of the carbon-based polymer is higher than that of the conventional carbon-based polymer which is simply composed of a repeating structure of —CX ₂ — (X represents a halogen atom). It is also clear from recent studies that the number will increase. When comparing the binding energies between two atoms, this is the C—N bond (770 kJ / mo).
It is also intuitively understood that l) is larger than the C—C bond (607 kJ / mol). Furthermore, the introduction of the functional groups as described above increases the polarity of the carbon-based polymer, and the electrostatic adsorption force to the wafer that is negatively charged during etching is also increased, which also protects the surface of the carbon-based polymer. The effect improves.

By thus strengthening the film quality of the carbon-based polymer itself, the incident ion energy required for anisotropic processing can be reduced and the resist selectivity can be improved. This makes it possible to form an etching mask that can withstand practical use even from a relatively thin photoresist coating, and prevent the occurrence of processing size conversion differences, but without sacrificing the high resolution in photolithography. .. In addition, since the amount of carbon-based polymer required to achieve high anisotropy and high selectivity can be reduced, particle contamination can be reduced as compared with the prior art. In addition, the residual chlorine existing in the form of being incorporated in the carbon-based polymer is also reduced, so that the after-corrosion resistance is also improved.

Further, the reduction of the incident ion energy naturally leads to the improvement of the underlayer selectivity.
The sputtering of the interlayer insulating film underlying the l-based material layer is reduced,
It is possible to suppress redeposition and the like on the pattern side wall portion. Therefore, the residual chlorine existing in the form of being incorporated in the redeposited material is also reduced, which also makes it possible to effectively suppress the after-corrosion.

The present invention is based on the above idea, but proposes a method aiming at further reduction of pollution and damage. The method is the above-mentioned etching
A sulfur-based compound capable of releasing sulfur (S) into plasma under discharge dissociation conditions is added to the gas. In this case, in addition to the carbon-based polymer which is the etching reaction product, S can also be used for sidewall protection. S
Depends on the conditions, but if the substrate (wafer) is temperature-controlled below about room temperature, it will deposit on its surface, and if it is heated above about 90 ° C., it easily sublimes, and thus becomes a source of particle contamination. There is no fear.

Further, a part of this S further reacts with N released from the nitrosyl group or the nitrile group to form various sulfur nitride compounds. A compound which mainly constitutes the above-mentioned sulfur nitride-based compound and which the present inventor expects to have a side wall protecting effect is polythiazyl (SN) _x . Regarding the properties and structure of polythiazyl in the single crystal state,
J. Am. Chem. Soc. , Vol. 29, p. 6
358-6363 (1975). It is a polymeric substance that stably exists at 208 ° C. under normal pressure and around 140 to 150 ° C. under reduced pressure. Therefore, under normal wafer temperature conditions where normal dry etching is performed, the film is deposited on the wafer, and the etching rate is reduced by competing with the sputter removal process at the vertical incidence plane of ions, and the pattern side wall portion plays a role of side wall protection. Fulfill Moreover, in the crystal of (SN) _x, the main chains composed of S-N-S-N -... Repeated covalent bonds are oriented parallel to each other. Therefore, this sulfur nitride compound mainly composed of (SN) _x can effectively prevent the intrusion of F ^{* and the} like. Further, even if ions accelerated by the conditions are incident, a so-called sponge effect is exerted due to a change in the bond angle or the conformation, and the ion impact can be absorbed or alleviated. In other words, the side wall protection effect is greater than that of a single S deposit, and the shock resistance against ion bombardment is also high. Furthermore, (SN) _x is 140 under reduced pressure.
When heated up to about 150 ° C, it is easily decomposed or sublimated and can be completely removed.

In addition to the above, halogens such as F ^* are contained in the plasma.
When a radical is present, S in (SN) _x above
A thiazyl halide having a halogen atom attached on the atom may also be produced. Further, when hydrogen-based gas is added to control the amount of F ^* produced, thiazyl hydrogen can also be produced. Furthermore, depending on the conditions, the number of S atoms in the molecule and N
It is also possible to produce a cyclic sulfur nitride compound having an imbalanced number of atoms, or an imide type compound in which an H atom is bonded to the N atom of these cyclic sulfur nitride compounds.

In any case, the above-mentioned sulfur nitride-based compound can be deposited on the wafer under normal wafer temperature conditions, and is removed by heating the wafer. In the present invention,
By expecting deposition of such S and sulfur nitride compounds, incident ion energy can be further reduced,
It is possible to thoroughly reduce damage. Further, by this, the amount of carbon-based polymer deposited can be relatively reduced, and particle contamination and after-corrosion can be more effectively reduced.

The present invention also proposes a method of thoroughly implementing measures against after-corrosion. That is, after the etching of the Al-based material layer is completed, plasma processing is performed using a processing gas containing a fluorine-based compound while heating the substrate (wafer). As a result, the residual chlorine remaining in the vicinity of the pattern is replaced with fluorine, and the vapor pressure of the side wall protective material that binds or stores the residual chlorine is increased by plasma radiation heat or direct heating of the wafer, which facilitates desorption. .. Therefore, even if water is adsorbed on the wafer after etching, a local battery using residual chlorine as an electrolyte is less likely to be formed, and corrosion of the Al-based pattern can be suppressed.

[0021]

EXAMPLES Specific examples of the present invention will be described below.

Example 1 In this example, an Al-based multi-layer film in which a barrier metal, an Al-1% Si layer, and an antireflection film were sequentially laminated was used as NOCl.
This is an example of etching using a (nitrosyl chloride) / Cl ₂ mixed gas. This process is shown in FIG.
A description will be given with reference to (b) and (d).

First, as an example, as shown in FIG. 1A, a barrier metal 4 having a thickness of about 0.13 μm and an Al-1% Si layer 5 having a thickness of about 0.3 μm are formed on the SiO ₂ interlayer insulating film 1. A Ti-based antireflection film 6 having a thickness of about 0.1 μm was sequentially laminated to form an Al-based multilayer film 7, and a resist mask 8 was further formed on the Al-based multilayer film 7 to prepare a wafer.
Here, the barrier metal 4 is composed of a Ti layer 2 having a thickness of about 0.03 μm and a TiO layer having a thickness of about 0.1 μm in order from the lower layer side.
The N layer 3 is sequentially laminated.

This wafer was set in an RF bias application type magnetic field microwave plasma etching apparatus, and as an example, the Al type multilayer film 7 was etched under the following conditions. NOCl flow rate 30 SCCM Cl ₂ flow rate 90 SCCM Gas pressure 2 Pa (= 15 mTor)
r) Microwave power 900 W (2.45 GHz) RF bias power 30 W (13.56 MHz) Wafer temperature Normal temperature Here, although NOCl alone cannot form an etching gas, one Cl atom is present in the molecule. Therefore, it is used together with Cl _{2 in} order to obtain a practical etching rate.

In this process, Cl is generated by ECR discharge.₂Oh
And Cl generated by dissociation from NOCl ^*The main etching species
And the radical reaction is_x ⁺, N⁺, NO⁺, NO
Cl ⁺Etching is assisted by ions such as
Progresses, the Al-based multilayer film 7 becomes AlCl_x, TiCl_xEtc.
Removed in shape. At the same time, the resist mask
CCl derived from the decomposition products of 8_xIs generated and
The trosyl group is incorporated into the structure to create a strong carbon-based
Limmer generated. This carbon-based polymer is
Production amount is higher than conventional process due to low power consumption
However, it is deposited on the side wall of the pattern and is shown in FIG.
The side wall protection film 9 is formed so that a small amount of high etching
Exerted resistance to ringing and contributed to anisotropic processing. As a result,
The Al-based wiring pattern 7a having a good anisotropic shape is formed.
Was made However, in the figure, each material layer after patterning
Is expressed by adding the subscript a to the code of the corresponding original material layer.
is there.

Further, with the RF bias power of the above level, the underlying SiO ₂ interlayer insulating film 1 was not sputtered and redeposited on the pattern side wall portion, and the early generation of after-corrosion was suppressed. The etching rate of the Al-based multilayer film 7 in this embodiment is about 950 nm /
The selection ratio to the resist was about 5.

After the completion of etching, the wafer was transferred to a plasma ashing apparatus attached to the above etching apparatus, and O ₂ plasma ashing was performed under normal conditions.
As a result, as shown in FIG. 1D, the resist mask 8 and the side wall protective film 9 were burned and removed. In the process of this example, since the amount of carbon-based polymer produced was small, the particle level did not deteriorate even if the number of wafers processed was increased.

Example 2 In this example, the same Al-based multilayer film was etched using a NOBr (nitrosyl bromide) / Cl ₂ mixed gas. The etching conditions in this embodiment are all the same as in Embodiment 1 except that NOBr is used instead of NOCl. However, since NOBr is a liquid substance at room temperature,
After evaporating by e-gas bubbling, etching
It was introduced into the chamber.

In this etching process, CCl _x , CB
r _x and a carbon-based polymer in which a nitrosyl group was incorporated were generated, and the sidewall protective film 9 was formed by these deposits. Particularly, in this embodiment, B is used as halogen.
Since r is involved, the surface of the resist mask 8 is protected by CBr _x, so that the resist selectivity is about 6 which is higher than that of the first embodiment. Also, Br is S
Since the reactivity with respect to i is low, the selectivity with respect to the underlying SiO ₂ interlayer insulating film 1 is improved as compared with the first embodiment.

Example 3 In this example, the same Al-based multilayer film was used as NOCl / S ₂ Cl _2.
This is an example of etching using a mixed gas. First, the wafer shown in FIG. 1A was set in a magnetic field microwave plasma etching apparatus, and as an example, the Al-based multilayer film 7 was etched under the following conditions.

NOCl flow rate 50 SCCM S ₂ Cl ₂ flow rate 70 SCCM Gas pressure 2 Pa (= 15 mTorr)
r) Microwave power 900 W (2.45 GHz) RF bias power 15 W (13.56 MHz) Wafer temperature 0 ° C. (using ethanol-based refrigerant) Here, the wafer cooling is the cooling pipe embedded in the wafer mounting electrode. Then, an ethanol-based refrigerant was supplied from a chiller installed outside the apparatus and circulated.

In this etching process, in addition to CCl _x and a carbon-based polymer containing a nitrosyl group, S which is dissociated and produced from S ₂ Cl ₂ and nitridation which is produced by the reaction of S with N supplied from the nitrosyl group are produced. The sulfur compound also contributed as a constituent component of the sidewall protective film 9. Therefore, FIG.
As shown in (b), the Al-based wiring pattern 7a having a good anisotropic shape could be formed even under the condition that the RF bias power was further lowered as compared with Example 1.
The etching rate of the Al-based multilayer film 7 in this embodiment is
Although the wafer cooling rate and the amount of deposits were slightly lower than those of Example 1 to about 900 nm / min, the selectivity ratio to resist was improved to about 9. As a result, the decrease in the film thickness of the resist mask 8 and the receding of the edge were hardly recognized. In addition, the amount of carbon-based polymer produced could be reduced to the extent that S deposition can be expected, and the underlying bias was improved by lowering the bias, and reattachment of the SiO ₂ interlayer insulating film 1 by sputtering was suppressed. For this reason, the after-corrosion resistance was also greatly improved.

When O ₂ plasma ashing was performed after the etching was completed, as shown in FIG. 1D, the resist mask 8 and the side wall protective film 9 were quickly removed. Here, the side wall protective film 9 contains carbon-based polymer, S, sulfur nitride-based compound, etc., which are sublimated / decomposed by plasma radiation heat or reaction heat, and are also removed by combustion reaction by O ^*. , No particle contamination was left on the wafer.

Example 4 In this example, the same Al-based multilayer film was used as NOBr / S ₂ Cl.
₂ is an example of etching using a mixed gas. First, the wafer shown in FIG. 1A was set in a magnetic field microwave plasma etching apparatus, and as an example, the Al-based multilayer film 7 was etched under the following conditions.

NOBr flow rate 30 SCCM S ₂ Cl ₂ flow rate 90 SCCM Gas pressure 2 Pa (= 15 mTorr)
r) Microwave power 900 W (2.45 GHz) RF bias power 10 W (13.56 MHz) Wafer temperature 0 ° C. (Ethanol-based refrigerant used) In this etching process, Br was involved in the etching reaction system to obtain Example 3 Even though the RF bias power was lowered, the anisotropic processing could be performed well. The resist selectivity was about 10 which was higher than that of Example 3. Further, the selectivity and the after-corrosion resistance with respect to the underlying SiO ₂ interlayer insulating film 1 were also improved.

Example 5 In this example, the same Al-based multi-layer film was etched using a NO ₂ Cl (nitrile chloride) / S ₂ Cl ₂ mixed gas, and then plasma treated using a CF ₄ / O ₂ mixed gas. It is an example of performing. This process is shown in FIG. 1 (a), (b),
Description will be given with reference to (c) and (d).

First, the wafer shown in FIG. 1 (a) was set in a magnetic field microwave plasma etching apparatus, and as an example, the Al-based multilayer film 7 was etched under the following conditions. NO ₂ Cl flow rate 50 SCCM S ₂ Cl ₂ flow rate 70 SCCM Gas pressure 2 Pa (= 15 mTorr)
r) Microwave power 900 W (2.45 GHz) RF bias power 15 W (13.56 MHz) Wafer temperature 0 ° C. (using ethanol-based coolant) In this etching process, nitrile group or nitrosyl group partially decomposed is introduced to enhance. While the carbon-based polymer, S dissociated and produced from S ₂ Cl _2, and the sulfur nitride-based compound were mixed to form the sidewall protective film 9, the etching proceeded anisotropically.

Next, the wafer was transferred to the post-processing chamber attached to the above-mentioned etching apparatus, and plasma processing was performed under the following conditions as an example. CF ₄ flow rate 100 SCCM O ₂ flow rate 50 SCCM Gas pressure 10 Pa (= 75 mTorr
r) Microwave power 900 W (2.45 GHz) RF bias power 0 W (13.56 MHz) Wafer temperature 100 ° C. By this plasma treatment, as shown in FIG. 1 (c), the sidewall protection film 9 is rapidly removed. It was The mechanism of this removal is combustion by O ^{* for} carbon-based polymers, increase in vapor pressure due to fluorine substitution, etc., and sublimation / decomposition by O-wafer heating for S and sulfur nitride-based compounds, and O.
^* Due to combustion, which is formed like a SF _x by F ^*.

By this plasma treatment, Cl absorbed or bound to the resist mask 8 was also replaced with F.

Then, normal O ₂ plasma ashing was performed to remove the resist mask 8 as shown in FIG. 1 (d). The wafer after resist ashing was opened to the atmosphere on a trial basis, but after-corrosion was not observed even after 72 hours.

Example 6 In this example, the same Al-based multilayer film was used as NOBr / S ₂ Cl ₂
In this example, etching is performed using a mixed gas, and then plasma treatment is performed using a CF ₄ / O ₂ mixed gas. In this example, the wafer shown in FIG. 1A was set in a magnetic field microwave plasma etching apparatus, the Al-based multilayer film 7 was etched under the same conditions as in Example 4, and then the same conditions as in Example 5 were used. Plasma treatment was performed.

In this process, since the Br-based chemical species are used in the etching to perform the etching with a high resist selection ratio, the deposition amount of the carbon-based polymer is further reduced.
The wafer after resist ashing was opened to the atmosphere on a trial basis, but after-corrosion was not observed even after 96 hours.

The present invention has been described above based on the six embodiments, but the present invention is not limited to these embodiments. For example, nitrosyl chloride has the above N
In addition to OCl, NOCl ₂ (nitrosyl dichloride) and NOC
The presence of l ₃ (nitrosyl trichloride) is known. Similarly, the presence of dibromide and tribromide in nitrosyl bromide is also known. Also, a nitrosyl compound having both Cl and Br in the molecule can be present. Any of these compounds can be used in the present invention.

Examples of the nitrile compound include NO ₂ C mentioned above.
In addition to 1, NO ₂ Br or the like can also be used. By the way, since chloride and bromide are picked up in each of the above-mentioned examples, it is easily inferred to use nitrosyl fluoride (NOF) or nitrile fluoride (NO ₂ F). However, F ^* produced from these compounds is combined with Al and Ti to produce AlF _x , TiF _x, etc. having a low vapor pressure,
Since it is highly likely that the etching rate is lowered or the particle level is deteriorated, it is necessary to consider such as heating the wafer within a range that does not deteriorate the heat resistance of the resist mask.

Discharge Sulfur in plasma under discharge dissociation conditions
As the sulfur-based compound capable of releasing sulfur, the above S₂Cl
₂And S₃Cl₂, SCl₂Sulfur chloride such as S₃B
r₂, S₂Br₂, SBr₂Sulfur bromide such as H₂S etc.
Can be used. S ₂F₂, SF₂, SF_Four，
S₂F_TenSulfur fluoride such as can also release S
But both are F^*Is generated, so the above consideration is necessary.
It is important.

The etching gas used in the present invention includes:
In order to expect a sputtering effect, a dilution effect, a cooling effect, etc., a rare gas such as Ar or He may be appropriately added. As the gas used for the plasma treatment, the above-mentioned CF is used.
_{In addition to the 4} / O ₂ mixed gas, NF ₃ / O ₂ mixed gas or the like can be used.

Further, it goes without saying that the structure of the sample wafer, the etching apparatus used, the etching conditions and the like can be changed as appropriate.

[0048]

As is apparent from the above description, according to the present invention, an etching gas containing a halogen compound containing at least one of a nitrosyl group and a nitrile group is used for etching an Al-based material layer.
It is possible to achieve high anisotropy and high selectivity even by strengthening the film quality of the carbon-based polymer and reducing the deposition amount.
Therefore, it is possible to prevent the occurrence of processing size conversion difference and significantly improve the after-corrosion resistance. Further, by using the halogen compound in combination with a sulfur-based compound capable of releasing S under discharge dissociation conditions, it is possible to achieve further high selectivity, low pollution, low damage and the like. Moreover,
Since S that has contributed to sidewall protection can be easily removed by sublimation, it does not cause particle contamination.

Therefore, the present invention is extremely effective for manufacturing a semiconductor device which is designed based on a fine design rule and which requires high integration, high performance and high reliability.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a process to which the present invention is applied in the order of steps, (a) shows a state where a resist mask is formed on an Al-based multilayer film, and (b) shows a side wall protective film. The state in which an Al-based wiring pattern having an anisotropic shape is formed while being formed, (c) shows a state in which the sidewall protective film has been removed, and (d) shows a state in which the resist mask has been removed by ashing.

[Explanation of symbols]

1 ... SiO ₂ interlayer insulating film 2 ... Ti layer 3 ... TiON layer 4 ... barrier metal 5 ··· Al-1% Si layer 6 ... TiON antireflection film 7 ... Al system Multi-layer film 7a ... Al-based wiring pattern 8 ... Resist mask 9 ... Side wall protection film

Claims (3)

[Claims] 1. An aluminum-based material layer on a substrate is etched using an etching gas containing a halogen compound having a halogen atom and at least one functional group of a nitrosyl group or a nitrile group in a molecule. Method for forming aluminum pattern. 2. An etching method comprising a halogen compound having at least one functional group of a nitrosyl group or a nitrile group and a halogen atom in a molecule, and a sulfur compound capable of releasing sulfur into plasma under discharge dissociation conditions. A method for forming an aluminum-based pattern, which comprises etching an aluminum-based material layer on a substrate using a gas. 3. After the etching of the aluminum-based material layer according to claim 1 or 2, the plasma processing is performed using a processing gas containing a fluorine-based compound while heating the substrate. And a method of forming an aluminum-based pattern.