JPH0714824A - Plasma treatment - Google Patents

Abstract

PURPOSE:To shorten the time for removing a reaction product while an oxidation of a multilayer film and the generation of corrosion of the multilayer film are inhibited by a method wherein after the multilayer film consisting of an aluminum-containing film, a TiW film and the like is subjected to etching treatment, a treatment using oxidizing gas and hydrogen-containing gas is added in the same etching chamber. CONSTITUTION:A treatment gas is introduced in an etching chamber 6, a microwave is generated in the chamber 6 to introduce the microwave in a quartz belljar 7, a magnetic field is made to act in the belljar 7 by a coil 11 and strong plasma is generated. Moreover, a multilayer film consisting of an aluminum- containing film, a TiW film and a TiN film is subjected to etching treatment by using halogen gas, such as BCl3 gas, Cl2 gas or HBr gas, or halogen mixed gas. Subsequently, a plasma treatment using the mixed gas of O2 gas and CH3OH gas is performed in the same etching chamber 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma treatment method for a film containing aluminum and a laminated structure film such as TiW or TiN.

[0002]

2. Description of the Related Art The conventional method is as follows: Proceedings 456P "HBr"
An example is described in "In Situ Chamber Cleaning in RIE". In this method, a plasma treatment method using a mixed gas such as O ₂ or SF ₆ + O ₂ for removing the reaction products deposited in the chamber during the etching treatment of the Si-based film is shown. It has been shown that objects can be removed.

[0003]

The deposits formed by the reaction products generated during the etching process cause fogging of the emission monitor window for end point detection, which causes non-uniformity of etching performance and generation of particles due to a decrease in the accuracy of end point detection. Become.
For this reason, the deposit formed by the reaction product is subjected to a cleaning process by measuring the plasma emission intensity and the number of particles generated, and appropriately according to a certain management standard.

On the other hand, the wiring material used for the LSI is composed of a layer containing aluminum and TiW in order to improve the reliability of the wiring.
Since a TiN film or the like is laminated, a plasma processing method capable of precisely processing a multilayer film without corrosion and having little change in etching performance even in continuous etching processing is required.

In the conventional method, no consideration is given to a layer containing aluminum, a multilayer film such as TiW and TiN films, and a plasma processing method for each sheet.

An object of the present invention is to provide a plasma processing method which suppresses oxidation of a multilayer film, reduces residual halogen components, suppresses corrosion, and shortens reaction product removal time to obtain stable etching performance. To provide.

[0007]

In order to achieve the above object, in a plasma treatment of a film containing aluminum and a multilayer film of TiW, TiN, etc., an oxidizing gas and hydrogen are stored in the same etching chamber after the etching process of the multilayer film. By adding a plasma treatment using a gas containing gas, the residual halogen component is reduced and the generation of corrosion of the multilayer film is suppressed while the reaction products are removed and a stable etching treatment is achieved. Is.

[0008]

In the plasma processing of the aluminum-containing film and the multilayer film of TiW, TiN, etc., plasma processing using an oxidizing gas and a gas containing hydrogen is performed in the same etching chamber after etching the multilayer film for each sample. To do. At this time, the oxidizing gas mainly removes reaction products (C, H, O components) derived from the photoresist deposited in the etching processing chamber. On the other hand, the gas containing hydrogen suppresses the oxidation of the film containing aluminum and the side surfaces of the multilayer film such as TiW and TiN. The multilayer film is mainly composed of BCl ₃ ,
Etching is performed by using a halogen gas such as Cl ₂ or HBr or a halogen-based mixed gas. The side surfaces of the multilayer film are oxidized during the plasma processing using only the oxidizing gas, and the halogen component remaining near the side surfaces of the multilayer film during the etching processing cannot be sufficiently removed. It is important that residual halogen components are not left in the film because they cause corrosion of the multilayer film after etching.
The gas containing hydrogen is used to suppress the oxidation of the side surface of the multilayer film and to remove the residual halogen components as HCl and HBr.

As a result, a film containing aluminum and Ti
It is possible to remove the reaction products deposited in the etching chamber while suppressing the oxidation of the multilayer film of W, TiN, etc. and suppressing the occurrence of corrosion by reducing the residual halogen component.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a microwave etching apparatus which is an example of an apparatus for carrying out the present invention. A sample table 8 on which a sample 15 is placed is provided in the etching chamber 6, and a quartz bell jar 7 is attached to the upper part of the etching chamber 6 so as to face the sample table 8. The etching chamber 6 is connected to a processing gas supply source (not shown) and supplies a processing gas into the etching chamber 6, and a vacuum pump (not shown) is connected to the etching chamber 6 to reduce the pressure in the etching chamber 6 to a predetermined pressure. An exhaust port 14 for exhausting air is provided. On the sample table 8,
The high frequency power supply 13 is connected.

The processing gas introducing pipe 1 is constructed by the apparatus having the above construction.
2. The processing gas is introduced into the etching chamber 6 from ^{2 and the} inside of the etching chamber 6 is maintained at 1.33 × 10 ² Pa to 2.67 Pa, and the applied amount is 100 W to 1500 by the magnetron 10.
A microwave of W is generated and introduced into the quartz bell jar 7 by the waveguide 9, and a magnetic field of 400 to 1500 gauss is applied to the inside of the quartz bell jar 7 by the coil 11. Due to these, strong plasma is generated even in a low pressure region by the action of the microwave and the magnetic field.

Further, the high frequency power source 13 can control the ion energy incident on the sample stage 8.

When the sample shown in FIG. 2 is processed using this apparatus, first, a film containing aluminum and TiW, TiN are prepared by using a halogen gas such as BCl ₃ , Cl ₂ , HBr or a mixed gas of halogen series. Is subjected to etching treatment, and subsequently in the same etching chamber 6,
Plasma treatment is performed using a mixed gas of O ₂ and CH ₃ OH. In FIG. 2, 1 is a mask resist, 2 is a film containing aluminum, 3 is a TiW film, 4 is a base film, and in this case, a SiO ₂ film and 5 are Si substrates.

In FIG. 3, each sheet is processed for 20 seconds, the O ₂ flow rate is 300 cc / min, and the CH ₃ OH flow rate is 40 cc / mi.
n, pressure 1.33 Pa, microwave input power 1000 W
2 shows the emission intensity of aluminum after plasma treatment. FIG. 4 shows the first, the 25th, and the 25th continuous etching treatments when the 25th continuous etching treatment was performed, followed by an O ₂ flow rate of 300 cc / min and a pressure of 1.3.
20 at 3 × 10 ¹ Pa and 1000 W microwave input power
The emission intensity of aluminum after plasma treatment with O ₂ gas for 1 minute is shown.

In the conventional method shown in FIG. 4, the time required for removing the reaction product when etching 25 sheets is 1200 seconds, and in the case of the present invention shown in FIG. 3, 20 seconds per sheet is 500 seconds in total. Met. According to the present invention, the reaction product removal time can be reduced by about 60%.

Further, since the plasma treatment is performed for each sheet, the deposition of reaction products is very small. Therefore, the change in the emission intensity of aluminum is small and stable etching performance can be obtained every time. Further, since the gas containing hydrogen is mixed, the halogen component remaining during the etching process can be effectively removed, and the occurrence of corrosion of the multilayer film until the anticorrosion process including the resist removal which is separately performed can be suppressed.

[0018]

According to the present invention, the multilayer film of the film containing aluminum and the TiW, TiN film is suppressed from being oxidized and the residual halogen component is reduced, and the occurrence of corrosion is suppressed and deposited in the etching chamber. This has the effects of shortening the time required for removing the reaction product and enabling stable etching treatment.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of a microwave plasma processing apparatus which is an example of an apparatus for carrying out a plasma processing method of the present invention.

FIG. 2 is a cross-sectional view of a sample before etching.

FIG. 3 is an explanatory diagram showing a change in emission intensity of aluminum after a cleaning process is performed every time one sample is processed.

FIG. 4 is an explanatory diagram showing a change in emission intensity of aluminum after performing plasma processing using a conventional gas when 25 samples are continuously processed.

[Explanation of symbols]

1 ... Resist (mask), 2 ... Aluminum film, 3 ... T
iW film, 4 ... Base SiO ₂ film, 5 ... Silicon substrate, 6 ...
Etching chamber, 10 ... Magnetron, 11 ... Coil, 1
2 ... Processing gas introduction pipe, 13 ... High frequency power supply, 15 ... Sample.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/3205

Claims (1)

[Claims] 1. In plasma processing of a film containing aluminum and a multilayer film of TiW, TiN, etc., a process using an oxidizing gas and a gas containing hydrogen is added in the same etching chamber after the etching process of the multilayer film. A characteristic plasma processing method.