JPH03280535A - Dry etching device - Google Patents

Abstract

PURPOSE:To make possible the formation of highly reliable, minute interconnections by setting up a means for heating a wafer in an ashing chamber or setting up a separate heating chamber to heat the wafer after dry etching of interconnection in order to completely remove residual chlorine. CONSTITUTION:The dry etching device consists of an etching chamber 1, ashing chamber 2, and a load-lock chamber 4. The ashing chamber 2, in addition to having a stage 7b to support a wafer 6 and an electrode 10 to generate the plasma, is outfitted with a lamp 11 above the stage 7b to heat the wafer 6. For example, after Al-Cu interconnections are etched in the etching chamber 1, resist on the wafer 6 is removed in the ashing chamber 2 by an oxygen plasma. Next, the temperature is raised to about 200 deg.C by the lamp 11 to vaporize and remove residual chlorine. In this way, chlorine is completely removed from the etched wafer 6, eliminating the possibility of the formation of HCl through a reaction with water in the air and potential corrosion of interconnections.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dry etching apparatus that utilizes plasma.

[Conventional technology]

2. Description of the Related Art As semiconductor devices have become highly integrated in recent years, the reliability of wiring formed on semiconductor substrates has become important. Aluminum is generally used as a wiring material for semiconductor devices, but as wiring becomes finer, electromigration of aluminum wiring becomes a problem. A countermeasure to this problem has been taken by adding several percent of copper to aluminum.

A dry etching apparatus as shown in FIG. 4 is used to pattern the ^1-Cu wiring.

Etching is performed in the following sequence. That is,
After placing the wafer in the load lock chamber 4 and evacuating it,
The transfer robot 5 sends it to the etching chamber 1. After that, chlorine-based gas is introduced, and high-frequency power is applied to generate plasma. The ANCu wiring is etched by reactive ions containing chlorine in this plasma.
The etched wafer is sent to the ashing chamber 2 by a transfer robot, and the resist as a mask material is removed by oxygen plasma. Finally, the wafer is sent from the ashing chamber 2 to the load lock chamber 4, the load lock chamber 4 is opened to the atmosphere, and the wafer is taken out from the apparatus.

In FIG. 4, 9 is a gate valve.

[Problem to be solved by the invention]

AI! - In dry etching of Cu wiring, the vapor pressure of the AIC gas produced as a reaction product is low and it is not easy to vaporize, so the chlorine contained in the etching gas is easily adsorbed to the wiring pattern.Therefore, the chlorine adsorbed to the wiring pattern Minutes and moisture in the air react to produce HC/. This causes the problem of corrosion of the Ae wiring.

This situation is schematically shown in FIG. FIG. 5(a) is a cross-sectional view of a wafer that has not been removed from the dry etching apparatus. A corroded portion 101 grows on the wiring 100. Same figure (b)
is the cross-sectional shape of the wafer after the next step of washing with water. Since the corroded portion 101 is water-soluble, the wiring 100 may be missing. If the corrosion progresses further, there is a problem that the wiring will break.

Therefore, in the conventional equipment shown in Figure 4, a method is used in which chlorine is removed at the same time as the resist in an adjacent ashing chamber, but even with this method, it is not possible to completely remove the residual salt adsorbed on the wiring pattern. Therefore, the problem remains that corrosion of the A/-Cu wiring progresses.

[Means to solve the problem]

A dry etching apparatus according to a first aspect of the invention is a dry etching apparatus having an etching chamber equipped with means for generating plasma and an ashing chamber equipped with means for removing a photoresist film. This means that the

The dry etching apparatus of the second invention includes an etching chamber equipped with means for generating plasma, an ashing chamber equipped with means for removing the photoresist film, and a heating chamber equipped with means for heating the wafer to a predetermined temperature. and a conveying means for conveying the wafer to the above three spaces under vacuum.

C Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an ashing chamber used in a first embodiment of the present invention.

The dry etching apparatus is composed of an etching chamber 1, an ashing chamber 2, and a load lock chamber 4 as in the conventional example shown in FIG. 4, but the ashing chamber 2 supports the wafer 6 as shown in FIG. In addition to the stage 7b for heating and the electrode 10 for generating plasma, a lamp 11 for heating the wafer 6 is provided above the stage 7b.

According to the first embodiment configured in this way, after the Aj'-Cu wiring, for example, is etched in the etching chamber 1, the resist on the wafer 6 is removed by oxygen plasma in the ashing chamber 2. Approximately 200 by lamp 11
℃ to vaporize and remove residual chlorine.

FIG. 2 is a sectional view of an ashing chamber used in a second embodiment of the present invention.

Heating is performed by a heater 8 embedded within the stage 7b. In this case, since temperature control is easily performed by turning on and off the heater, there is an advantage that the temperature of the wafer 6 can be kept accurately constant.

FIG. 3 is a schematic plan view of a third embodiment of the present invention.

In the third embodiment, the etching chamber 1. Ashing room 2.
It mainly consists of a heating chamber 3, a load lock chamber 4, and a transfer robot 5. A wafer 6 is placed in the heating chamber 3 in the same way as the ashing chamber shown in FIG. 1 or 2. stage 7c
and a lamp 11 or heater 8 that heats the wafer 6.

In the third embodiment, etching is performed in the following sequence.

First, a wafer 6 is placed in the load lock chamber 4, evacuated, and sent to the etching chamber 1 by the transfer robot 5. Therefore, chlorine-based etching gas was introduced into etching chamber 1.
By applying high frequency power and generating plasma, ^e-Cu
Etch the wiring.

Next, the wafer 6 is sent to the ashing chamber 2 by the transfer robot 5, and the resist is stripped off using oxygen plasma.

Next, the wafer 6 is sent to the heating chamber 3 by the transfer robot 5.

Here, the wafer 6 is heated to 200° C. or higher using a halogen lamp or heater.

The heating time to 200°C is about 1 minute. The wafer 6 sent to the heating chamber 3 has most of the chlorine removed in the ashing chamber 2, but by heating it to about 200° C. in the heating chamber 3, the residual chlorine can be vaporized more efficiently. becomes possible.

Finally, the wafer 6 is returned to the load lock chamber 4, and the load lock chamber 4 is opened to the atmosphere and taken out of the apparatus.

The wafer 6 etched in such a sequence is
Since the chlorine content is completely removed in the heating chamber 3, when it is taken out into the atmosphere, it will not react with moisture in the air and generate H(1'), so it will not corrode the wiring.

As a processing method in the heating chamber 3, in addition to the above-mentioned processing in a vacuum, oxygen gas is introduced during the processing and the temperature is raised to about 200°C to form an alumina film on the Af-Cu wiring. There is a way. A passivated by this alumina film
The j7-Cu interconnect is more resistant to corrosion.

〔Effect of the invention〕

As explained above, in the present invention, by providing a means for heating the wafer in the ashing chamber or by providing a separate heating chamber, the wafer can be heated after dry etching the wiring, so that the residual chlorine content can be completely removed. Since it can be removed quickly, the wiring will not be corroded. Therefore, there is an effect that fine wiring with excellent reliability can be formed.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of the ashing chamber used in the first and second embodiments of the present invention, and FIG. 3 is a sectional view of the ashing chamber used in the first and second embodiments of the present invention.
FIG. 4 is a schematic plan view of a conventional dry etching apparatus, and FIG. 5 is a cross-sectional view of a semiconductor chip for explaining the state of corrosion of kl-Cu wiring. 1... Etching room, 2... Ashing room, 3...
・Heating chamber, 4... Load lock chamber, 5... Transfer robot, 6... Wafer 7a, 7b, 7c... Stage, 8... Heater 9... Gate valve, 10.
...Electrode, 11...Lamp, 100...Wiring, 10
DESCRIPTION OF SYMBOLS 1... Corrosion part, 102... Oxide film, 103... Substrate.

Claims (1)

[Claims] 1. In a dry etching apparatus having an etching chamber equipped with means for generating plasma and an ashing chamber equipped with means for removing a photoresist film, means for heating a wafer in the ashing chamber. A dry etching device characterized by being provided with. 2. An etching chamber equipped with means for generating plasma, an ashing chamber equipped with means for removing the photoresist film, a heating chamber equipped with means for heating the wafer to a predetermined temperature, and the above three spaces under vacuum. A dry etching apparatus comprising: a conveying means for conveying a wafer;