JP3403595B2 - Processing method of wiring material - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates relates to a method for processing a wiring material, a method for processing of wiring material anticorrosion treatment is performed after the etching treatment in particular Al-based multilayer wiring material.

[0002]

2. Description of the Related Art In the case of a conventional sample , for example, JP-A-58-8 is used.
As described in Japanese Patent No. 7276, anticorrosion treatment is performed by performing ashing treatment with plasma of a mixed gas of fluorocarbon (for example, CF ₄ ) and oxygen (O ₂ ).

[0003]

The above-mentioned prior art does not take into consideration the removal of residual deposits after etching, and the residual deposits adhering to the side wall of the film to be etched cannot be sufficiently removed. When an Al-based wiring film by chlorine-based gas, particularly a laminated wiring material using a TiW film or a TiN film as a barrier metal layer under the Al-based wiring film is etched, a slight chlorine component remains after the etching process. Then, there is a problem that the local battery action between the wiring film materials and the chlorine component contained in the residual deposit component cause electrolytic corrosion on the Al-based wiring film to easily cause corrosion.

An object of the present invention is to provide a machining method for a wiring material capable of providing a high <br/> have corrosion protection for the sample having a wiring material formed by laminating a barrier metal layer and the barrier metal .

[0005]

[Means for Solving the Problems] The above object is to evacuate.
Etching chamber and post-processing chamber are connected via a buffer chamber
Etching and post-treatment are performed continuously under vacuum
Using continuous processing equipment, aluminum-based wiring film and barrier
The sample with the wiring material formed by laminating the
The plasma of chlorine gas is used to
Etching is performed using a mask as a mask,
Form a wiring with a minium-based wiring film and a barrier metal,
Moreover, after the etching treatment, the sample is treated in the post-treatment chamber.
Plas containing hydrogen and oxygen components continuously under vacuum at
Attached by the etching process by exposing to
Residual deposits containing the resist components and chlorine components removed
Exposure to oxygen or plasma containing oxygen
Mask of the resist used in the etching process
Is achieved by removing

[0006]

In the sample having the wiring material formed by laminating the barrier metal layer and the aluminum wiring film, the plasma of the gas containing the hydrogen component and the oxygen component which reacts with the chlorine component of the deposit remaining on the sample after the etching treatment. The chlorine-based component, especially the chlorine component (Cl), of the residual deposit attached to the sample by the etching process reacts with the hydrogen component (H) to effectively become hydrogen chloride (HCl) and is effectively removed. Therefore, even in the case of a wiring material sample in which a small amount of chlorine component is removed and a barrier metal layer and an aluminum-based wiring film are laminated, high corrosion protection performance can be obtained without causing electrolytic corrosion due to local battery action between the wiring film materials. You can

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an example of a continuous processing apparatus capable of continuously performing etching processing and post-processing under vacuum.

In the apparatus shown in FIG. 1, the buffer chamber 3, the load lock chambers 4 and 9, the etching chamber 6 and the post-treatment chamber 8 can be evacuated, and each chamber can be independently partitioned by an airtight device. It is possible. As a flow of processing using this apparatus, after the object to be processed is carried from the load side cassette 1 to the load lock chamber 4 by the rectilinear arm 2, the atmosphere is decompressed and exhausted by an exhaust device (not shown). After that, it is sent to the etching chamber 6 which has been evacuated by the turning arm 5 via the buffer chamber 3 which has been evacuated in advance. After performing a predetermined etching process in this etching chamber, it is also conveyed to the post-processing chamber 8 which has also been evacuated in advance by the turning arm 7. The object processed in the post-treatment chamber 8 is again conveyed to the load lock chamber 9 by the turning arm 7. After the load lock chamber 9 is separated from the buffer chamber 3 by the airtight device, the pressure inside the load lock chamber 9 is raised to the atmospheric pressure by N ₂ gas. Thereafter, the object to be processed is stored in the unload-side cassette 11 by the straight-moving arm 10 and a series of processing is completed.

FIG. 2 is a vertical sectional view of the post-processing chamber 8 shown in FIG. In FIG. 2, the plasma generation chamber 40 and the processing chamber 60 are kept in a vacuum, and the porous plate 5 made of aluminum is used.
It is divided by 0. In this case, the means for converting the introduced gas into plasma is performed by using microwaves, an opening is provided in the plasma generation chamber 40, and the quartz window 3 is provided in the opening.
0 is attached and the microwave oscillator 15 is provided at the end of the microwave waveguide 20.

The exhaust means is connected to the exhaust port 70 of the processing chamber 60 and comprises a pressure control valve 80 and a vacuum pump (not shown). The gas supply means is connected to a gas supply port 42 of the plasma generation chamber 40 via a gas supply pipe 44 from a gas supply source (not shown). In this case, the oxygen gas (O ₂ ) and the methanol gas (CH ₃ OH) containing the H component are adjusted by the flow rate control valves 46 and 48, respectively, so that the respective gases can be supplied.

A sample 90 is loaded into the processing chamber 60 and placed on the sample table 100. The sample table 100 can be heated by the heating device 105 so that the sample being plasma-processed can be heated.

With the apparatus having the configuration shown in FIGS. 1 and 2,
Frequency 2.45GH generated from microwave oscillator 15
The microwave of z travels in the microwave waveguide 20 and is guided into the plasma generation chamber 40 through the window 30 made of quartz. Microwaves are applied to the processing gas introduced into the plasma generation chamber 40 to generate plasma in the plasma generation chamber 40. A perforated plate 50 made of aluminum is provided between the plasma generation chamber 40 and the processing chamber 60 to prevent microwaves from advancing to the processing chamber 60 and to mainly guide radical components to the processing chamber 60. There is.

With the apparatus having the above structure, first, in the etching chamber 6, the sample 90 on which the Al-based wiring film is formed is etched using chlorine-based gas. After the etching, together with the resist as the mask material for forming the wiring pattern, the residual adhered substances (C,
H, Cl, Al, etc.) remain.

Next, the sample 90 on which the resist and the remaining adhered substances remain is sent to the post-processing chamber 8 for post-processing. Post-processing is performed as follows. In this case, the flow rate control valves 46 and 48 are adjusted so that oxygen gas (O ₂ ) and methanol gas (CH ₃ OH) are mixed and introduced into the plasma generation chamber 40, and microwaves are generated from the microwave oscillator 15 into plasma. It is introduced into the generation chamber 40. As a result, the hydrogen component (H)
Plasma of oxygen component (O) and other components is generated, and in this case, plasma mainly composed of radicals is guided to the processing chamber 60 side, and residual deposits and resist are removed.

H and O in the plasma react with chlorine components in the residual deposits to generate hydrogen chloride (HCl) and are removed, or become H ₂ O to dissolve and dilute the chlorine components. Then, the cause of corrosion of the Al-based wiring film is removed. Further, O in the plasma reacts with the resist to remove the resist.

As described above, since the post-treatment of the Al-based wiring film is performed by the plasma in which the methanol gas and the oxygen gas are mixed, the residual chlorine component in the residual deposit can be removed and the resist can be removed (ashing) by the oxygen component. Processing) can be performed.

It is to be noted that the description has been given of the case where the methanol gas and the oxygen gas are mixed to form plasma and the anticorrosion treatment and the ashing treatment are simultaneously performed, but the steps may be performed separately for each gas plasma. Further, the treatment gas may be switched so that the anticorrosion treatment is performed by plasma of a mixed gas of methanol gas and oxygen gas, and the ashing treatment is performed by plasma of only oxygen gas or plasma containing oxygen gas. good.

Next, a comparative example of the conventional post-treatment and the post-treatment of the present embodiment using the Al film as the Al-based wiring film according to the present embodiment will be described. FIG. 3 is a diagram showing the effect of reducing the residual chlorine amount according to this example. Process A in FIG. 3 shows a case where the conventional mixed gas plasma process of oxygen (O ₂ ) and carbon tetrafluoride (CF ₄ ) is performed for 2 minutes. The treatment B shows the residual chlorine amount when the treatment is performed for 1 minute with the mixed gas of methanol and oxygen and then the additional treatment is performed with the oxygen plasma for 1 minute. The sample used was an Al film wafer with a 6-inch wiring pattern and an Al film thickness of 800 nm.

Process A was carried out under the conditions of oxygen 400 cc / min, carbon tetrafluoride 20 cc / min and process pressure 160 Pa. Treatment B was first treated with methanol at 80 cc / min, oxygen at 400 cc / min and treatment pressure of 160 Pa, and then at oxygen of 400 cc / min and treatment pressure of 160 Pa. The treatment B was performed by setting the sample stage temperature to 250 ° C. at which the resist ashing rate was almost the same as that of the mixed gas of oxygen and carbon tetrafluoride.

The set temperature of the sample table 100 is preferably set to 200 ° C. to 350 ° C. in view of the relationship between the ashing rate of the resist and the thermal damage to the Al type wiring film.

As shown in FIG. 3, by carrying out the gas plasma treatment containing H and O, the chlorine component in the residual deposit could be reduced to about half in this case. Although the detailed action for reducing the chlorine component is not clear, H ₂ or H ₂ O component in the gas plasma containing H and O acts on the residual chlorine component (Cl) to generate hydrogen chloride (HCl). ,
It is considered that residual chlorine components are locally dissolved and diluted.

As described above, according to this embodiment, the amount of residual chlorine remaining after the Al-based wiring film etching treatment can be reduced much more than before, and the corrosion resistance of the Al-based wiring film after the etching treatment can be improved. There is an effect that can be.

In this embodiment, methanol (CH ₃ O
Although an example using H) was shown, ethanol (C ₂ H ₅ O
H) or acetone (CH ₃ COCH ₃ ) gas plasma, mixed gas plasma of these gases and oxygen (O ₂ ), or mixed gas of hydrogen (H ₂ ) or methane (CH ₄ ) and oxygen. It has a similar effect on the anticorrosion treatment of the Al-based wiring film.

Further, the oxygen gas plasma treatment is carried out after the plasma treatment using only the gas having H and O components such as methanol or the mixed gas of the gas such as methanol and oxygen to ensure the post treatment. It is better, however, if the resist can be ashed only by the plasma treatment with a mixed gas of a gas such as methanol and oxygen, the additional oxygen plasma treatment need not be performed.

Further, although the device configuration of the post-processing section described in the present embodiment is based on microwaves, RIE
Other methods such as a method may be used. Further, in the present embodiment, as shown in FIG. 1, the apparatus is capable of continuously performing the etching treatment and the post-treatment, but it is not limited to this.

Next, another example of the apparatus will be described with reference to FIGS. The apparatus shown in FIG. 4 has, for example, an apparatus configuration in which a known ashing processing mechanism is further provided in the apparatus shown in FIG. FIG. 5 shows the device configuration when it is installed externally.

These device configurations are particularly effective for anticorrosion treatment when a silicon (Si) -based material is used as a component of the resist material for pattern formation. When a silicon-based material is used as the component of the resist material (silicon-based inorganic resist or silicon photoresist, etc.),
In the oxygen radical-based ashing treatment, silicon in the resist material reacts with oxygen radicals to form silicon oxide and remains, so that there is a problem that the resist ashing treatment cannot be performed sufficiently. The remaining resist causes the occurrence of wiring corrosion due to residual chlorine and remains as a foreign substance when the insulating film is formed on the wiring film, which leads to a decrease in manufacturing yield such as defective insulation of the circuit, and therefore it is desirable to remove it as much as possible.

In the apparatus having the structure shown in FIGS. 4 and 5, after the plasma treatment with methanol or a mixed gas of methanol and oxygen is performed in the post-treatment (1), the silicon-based resist residue is removed. Post-processing (2) is performed. In the post-treatment (2), the sample stage temperature is set to 50 ° C. or lower and the plasma treatment using oxygen and fluorine gas is performed. Thereby, the anticorrosion treatment (post-treatment (1)) and the resist ashing treatment post-treatment (2) can be achieved.

In the post-treatment (2), that is, in the plasma treatment using oxygen and fluorine-based gas, when the sample 90 is a barrier metal, the sample table temperature is the TiN film, the TiW film, etc. which is the lower layer film of the Al-based wiring film. It is desirable to set the temperature to 50 ° C. or lower in order to prevent side etching.

[0030]

According to the present invention, the chlorine-based component of the residual deposit adhered to the sample during the etching process reacts with the hydrogen component, and even a slight chlorine-based component is effectively removed without remaining, thereby forming a barrier metal layer. Even for a sample of a wiring material formed by laminating an aluminum-based wiring film, there is an effect that high corrosion protection performance can be obtained without causing electrolytic corrosion due to a local cell action between the wiring film materials.

[Brief description of drawings]

1 is a plan view showing an example of an apparatus for carrying out the present invention.

FIG. 2 is a vertical cross-sectional view of the post-processing device when the device of FIG. 1 is viewed from AA.

FIG. 3 is a diagram showing the amount of residual chlorine which is the anticorrosion treatment effect of the present invention.

FIG. 4 is a schematic configuration diagram showing another example of a device for carrying out the present invention.

FIG. 5 is a schematic configuration diagram showing another example of a device for carrying out the present invention.

[Explanation of symbols]

8 ... Post-processing chamber, 15 ... Microwave oscillator, 40 ... Plasma generating chamber, 46, 48 ... Flow control valve, 60 ... Processing chamber, 8
0 ... Pressure control valve, 90 ... Sample, 100 ... Sample stage, 105
… Heating device.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yutaka Kakehi               502 Kandamachi, Tsuchiura City, Ibaraki Prefecture Co., Ltd.                 Hitachi Ltd. Mechanical Research Laboratory (72) Inventor Hironobu Kawahara               Yamaguchi Prefecture Kudamatsu-shi Oita-Toyoi 794 Stock               Hitachi, Ltd. Kasado Factory                (56) References JP-A-57-13743 (JP, A)                 JP-A-55-91842 (JP, A)                 JP 55-87438 (JP, A)                 JP-A-63-241933 (JP, A)                 JP 64-36023 (JP, A)                 JP 62-43132 (JP, A)                 JP-A-61-267325 (JP, A)                 Japanese Patent Publication 7-93293 (JP, B2)

Claims (3)

(57) [Claims] 1. An etchant is evacuated through a buffer chamber that is evacuated.
The etching chamber and the post-treatment chamber are connected, and etching and post-treatment are performed.
It is formed by laminating an aluminum-based wiring film and a barrier metal using a continuous processing device that continuously performs heat treatment under vacuum.
The sample containing the exposed wiring material is salted in the etching chamber.
Using the resist gas as a mask by the plasma of elementary gas
The aluminum-based wiring film and
After forming the wiring by the rear metal and after the etching treatment, the sample is treated in the post-treatment chamber.
Plas containing hydrogen and oxygen components continuously under vacuum at
Attached by the etching process by exposing to
Residual deposits containing the resist components and chlorine components removed
Exposure to oxygen or plasma containing oxygen
Mask of the resist used in the etching process
A method for processing a wiring material, comprising: 2. The method for processing a wiring material according to claim 1, wherein the plasma containing the hydrogen component and the oxygen component is a mixed gas of an oxygen gas and a gas selected from methanol, ethanol, and acetone. A method of processing a wiring material , which is plasma. 3. The wiring material processing method according to claim 1, wherein the plasma containing the hydrogen component and the oxygen component is plasma of a mixed gas of hydrogen and oxygen or a mixed gas of methane and oxygen. And a method of processing a wiring material.