JP3339523B2 - Ashing method - Google Patents

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 dry etching of an alloy and a method for preventing corrosion.

[0002]

2. Description of the Related Art Conventional methods for preventing corrosion are disclosed in
As described in JP-A-125618, the effect on the barrier metal and the underlying insulating film after the corrosion prevention treatment is not described.

[0003]

In the above 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.

[0004] The problems are as follows: 1) When the ashing is performed only with oxygen after the etching process of the laminated structure film (Al alloy + barrier metal, T, TiN, TiW, W, etc.), the anti-corrosion property is low. If ashing is performed with an oxygen + fluorine-based gas after the treatment, there is a problem that the barrier metal and the underlying insulating film (oxide film) are etched.

[0005] An object of the present invention is to provide a laminated structure using an Al alloy.
This may affect the barrier metal and the underlying insulating film in film formation.
Removes the mask material and remains on the workpiece.
Chlorine component is removed and after dry etching of Al alloy
Al alloy dry etching that can obtain excellent corrosion protection
Another object of the present invention is to provide a method for preventing corrosion .

[0006]

An object of the present invention is to provide a base insulating film.
A laminated structure film having an Al alloy and a barrier metal on it
After dry etching of the Al alloy on the formed substrate,
Set the plate temperature to 150-300 ° C, oxygen, argon, water
Remaining on the substrate using the active species of the mixed gas plasma
Remove resist mask and chlorine component, dry etch
This is achieved by performing corrosion protection of the Al alloy after the quenching .

[0007]

The oxygen gas mainly decomposes, reacts and removes the mask material. The inert gas is used as a diluting gas for hydrogen gas and as a carrier gas, and keeps the role of keeping the hydrogen gas explosion limit or less.

[0008] Hydrogen gas has a function of reacting and removing chlorine and chlorine-based components remaining in an object to be processed after processing.

[0009]

FIG. 1 shows an embodiment of the present invention. FIG. 1 shows a configuration diagram of a plasma processing apparatus. In FIG. 1, the frequency 2.45 GHz oscillated from the magnetron 2
The microwave of z propagates through the microwave waveguide 3 and is introduced into the processing chamber 1. Thereafter, 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 inlet 5 and is maintained at a constant pressure by the pressure adjusting valve 7. After the etching process is completed (the etching chamber is omitted), the workpiece 10 is transported to the main processing chamber through the gate valve 11 by vacuum transport, and is mounted on the wafer stage 9. The wafer stage is set to a desired temperature by a stage temperature controller. In the plasma processing apparatus having the above mechanism, the microwave oscillated from the magnetron 2 is introduced into a vacuum chamber maintained at a constant pressure by introducing a processing gas, and the plasma is generated between the quartz bell jar 4 and the microwave reflecting plate 6. Occurs. The wafer placed on the wafer stage 9 controlled at a constant temperature is generated at the upper portion, and the mask material 15 is removed by the active species of the plasma.

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

FIG. 3 shows shapes before and after ashing with oxygen + argon + hydrogen gas. Hydrogen gas was used by filling a cylinder with a mixed gas diluted with argon in advance so as to be 3.9% or less of the lower explosion limit. For this reason, no special attention needs to be paid to safety. In this embodiment, since a gas reactive with the barrier metal and the underlying insulating film is not used in overashing, a desired shape can be obtained.

Ashing conditions range from O ₂ 100 to 1000 m
1 / min, Ar 100-1000 ml / min, H ₂ is O ₂ + Ar 3
% Or less, pressure 0.5 ~ 2.0Torr, microwave output 100 ~ 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 respect to the barrier metal and the underlying insulating film, the mask material can be removed without affecting the barrier metal and the underlying insulating film during overashing. , It is possible to prevent corrosion.

Further, by using explosive hydrogen gas at 3.9% or less of the lower explosion limit, there is no need to provide safety equipment for the apparatus.

[Brief description of the drawings]

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

FIG. 2 is an explanatory view of an embodiment in which a mask material is removed with oxygen + fluorine gas using the apparatus of FIG. 1;

FIG. 3 is an explanatory diagram of an embodiment in which a mask material of oxygen + argon + hydrogen gas is removed.

[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 regulating valve, 8 ... Stage temperature controller, 9 ... Wafer stage, 10: workpiece (wafer), 11: gate valve, 15: mask material, 16: A
1 alloy, 17: barrier metal, 18: base insulating film.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fumio Shimizu 794, Higashi-Toyoi, Kazamatsu, Kudamatsu City, Yamaguchi Prefecture Inside the Kasado Plant of Hitachi, Ltd. Inside the Kasado Plant (72) Inventor Makoto Nawata 502, Kandachicho, Tsuchiura-shi, Ibaraki Pref. Machinery Laboratory, Hitachi, Ltd. (56) References JP-A-2-77125 (JP, A) JP-A-4-87322 ( JP, A) JP-A-3-68710 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/3065 H01L 21/027

Claims (1)

(57) [Claims] 1. A method according to claim 1, wherein the substrate temperature is set to 150 ° C. to 300 ° C. after dry etching of the Al alloy on the substrate on which the laminated structure film having the Al alloy and the barrier metal is formed on the base insulating film.
° C, and using the active species of a mixed gas plasma of oxygen, argon and hydrogen, the resist mask remaining on the substrate and
Al alloy after removal of chlorine component and dry etching
Alloy dry etchant characterized by anticorrosion protection
Anti-corrosion method after