JPH07263410A - Ashing method - Google Patents

Abstract

PURPOSE:To enable a mask member (resist) to be removed without affecting to high-corrosion proofness Al alloy barrier metal and an underneath oxide film at all by a method wherein H2 is added to arrest the chlorine component in a workpiece for enhancing the corrosion proofness so as to used a gas not reactive to the barrier metal and the underneath insulating film material. CONSTITUTION:A wafer stage 9 is set up a specific temperature by a stage temperature controller 8. In this plasma treater, the microwaves oscillated from a magnetron 2 are led into a vacuum chamber kept at a specific pressure by introducing treatment gas so as to produce plasma in a space between a quartz bell jar 4 and a microwave reflecting plate 6. Next, a mask member of a wafer 10 mounted on the wafer stage 9 is removed by an active species of plasma produced above said wafer 10 mounted on the stage 9 controlled at a specific temperature. That is, the title ashing method is performed using oxygen + argon + hydrogen gas without affecting a barrier metal and an underneath insulating film at all.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a method for removing a residual mask (resist) after alloy dry etching and a method for preventing corrosion.

[0002]

2. Description of the Related Art A conventional method for preventing corrosion is disclosed in, for example, Japanese Patent Laid-Open No.
No influence on the barrier metal and the underlying insulating film after the corrosion prevention treatment as described in JP-A-125618 is described.

[0003]

In the above-mentioned prior art, the substrate after Al etching was processed by using only oxygen as a processing gas or a mixture of oxygen and a fluorine-based gas.

As a problem, 1) the corrosion resistance is low when the ashing is performed only with oxygen after etching the laminated structure film (Al alloy + barrier metal, T, TiN, TiW, W, etc.) 2) The laminated structure film etching After the treatment, if ashing is performed with oxygen + fluorine-based gas, there is a problem that the barrier metal and the underlying insulating film (oxide film) are etched.

An object of the present invention is to provide an ashing method which has a high corrosion resistance and can remove a mask material (resist) without affecting the Al alloy barrier metal and the underlying oxide film.

[0006]

[Means for Solving the Problems] In order to enhance the anticorrosion property, H ₂ is added to capture chlorine components remaining in the object to be treated, 2. This is achieved by using a gas that does not react with the barrier metal and the underlying insulating film material.

[0007]

Function: Oxygen gas mainly decomposes and reacts with the mask material to remove it. The inert gas is used as a diluent gas of hydrogen gas and a carrier gas, and keeps the role of keeping the hydrogen gas explosion limit or lower.

Hydrogen gas has a function of reacting with and removing chlorine and chlorine-based components remaining in the processed object after processing.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a block diagram of a plasma processing apparatus. In FIG. 1, the frequency oscillated from the magnetron 2 is 2.45 GHz.
The microwave of z propagates through the microwave waveguide 3 and is introduced into the processing chamber 1. After that, it passes through the quartz bell jar 4 and is introduced into the vacuum chamber. The processing gas is introduced into the vacuum processing chamber through the gas introduction port 5 and kept at a constant pressure by the pressure adjusting valve 7. After the etching process is completed (the etching chamber is not shown), the object 10 is transferred to the main processing chamber through the gate valve 11 by vacuum transfer and placed on the wafer stage 9. The wafer stage is set to a desired temperature by the stage temperature controller. In the plasma processing apparatus having the above mechanism, the microwave oscillated from the magnetron 2 is introduced into the vacuum chamber where the processing gas is introduced and the pressure is kept constant, and the plasma is generated between the quartz bell jar 4 and the microwave reflection plate 6. Occurs. The mask material 15 is removed by the activated species of plasma generated at the upper part of the wafer placed on the wafer stage 9 controlled to a constant temperature.

An embodiment of the plasma processing chamber is shown in FIG.
This will be described with reference to FIG. FIG. 2 shows the shapes before and after ashing with oxygen + fluorine gas. The mask material 15 is removed by oxygen + fluorine gas, but after the mask material 15 is completely removed, extra ashing (hereinafter referred to as overashing) is performed to compensate for in-plane removal variation.
At this time, the excess fluorine component reacts with the barrier metal 17 and the base insulating film 18 and is etched, so that a desired anisotropic shape cannot be obtained after the ashing is completed.

FIG. 3 shows the shape before and after ashing with oxygen + argon + hydrogen gas. Hydrogen gas was used by filling a cylinder with a mixed gas previously diluted with argon so that the explosion limit was 3.9% or less. For this reason, no special attention is paid to safety. In this embodiment, the over-ashing does not use the gas reactive with the barrier metal and the underlying insulating film, so that the desired shape can be obtained.

The ashing condition range is O ₂ 100 to 1000 m
l / min, Ar 100 to 1000 ml / min, H ₂ is O ₂ + Ar 3
% Or less flow rate, pressure 0.5 to 2.0 Torr, μ wave output 100 to 1
500W, wafer mounting stage temperature 150-300 ℃, wafer temperature 150-300 ℃.

[0013]

According to the present invention, by using a gas having no reactivity with the barrier metal and the underlying insulating film, the mask material can be peeled off without affecting the barrier metal and the underlying insulating film during overashing. , Can prevent corrosion.

Further, by using explosive hydrogen gas in an explosion lower limit of 3.9% or less, it is not necessary to equip the apparatus with safety equipment.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a microwave plasma ashing apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an embodiment in which the mask material is removed with oxygen + fluorine gas using the apparatus of FIG.

FIG. 3 is an explanatory diagram of an example in which oxygen + argon + hydrogen gas is removed from the mask material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Processing chamber, 2 ... Magnetron, 3 ... Microwave waveguide, 4 ... Quartz bell jar, 5 ... Processing gas inlet, 6 ... Microwave reflector, 7 ... Pressure adjusting valve, 8 ... Stage temperature controller, 9 ... Wafer stage, 10 ... Object to be processed (wafer), 11 ... Gate valve, 15 ... Mask material, 16 ... A
l alloy, 17 ... Barrier metal, 18 ... Base insulating film.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Shimizu 794 Azuma Higashitoyo, Shimomatsu, Yamaguchi Prefecture Inside the Kasado Plant, Hitachi Ltd. (72) Hidenori Takei 794 Azuma Higashitoyo, Shimomatsu City, Yamaguchi Company Hitachi Ltd. Kasado Plant (72) Inventor Makoto Nawada 502 Kintatemachi, Tsuchiura City, Ibaraki Prefecture Hiritsu Plant Mechanical Research Laboratory

Claims (3)

[Claims] 1. A semiconductor manufacturing apparatus having a processing chamber for processing a semiconductor device, a mechanism for controlling a flow rate of a processing gas to be introduced into the processing chamber, and controlling the processing chamber to a predetermined vacuum pressure and having a plasma generating mechanism. As the processing gas, oxygen, hydrogen, an inert gas (He, A
r, Xe) is used. 2. The ashing method according to claim 1, wherein the flow rate of hydrogen is 3.9% or less of the total gas flow rate, and the temperature of the object to be treated is 150 ° C. to 300 ° C. for the treatment. The ashing method described in 1. 3. The ashing method according to claim 1, wherein in the ashing method, hydrogen gas is used as a gas filled in a cylinder at 3.9% or less with respect to an inert gas, and the gas is mixed with the oxygen gas for treatment. Method.