JPH11176802A - Etching of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for etching a semiconductor device formed with an antireflection film. SOLUTION: When a film 2, an antireflection film 3, and a resist pattern 4 are formed in this order, first, part of the antireflection film 3 which is not formed with the resist pattern 4 is etched for removed. After that, the resist pattern 4 is irradiated with visible light or far ultraviolet rays and the antireflection film 3 to increase their resistance and finally the film 2 is etched.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for etching a semiconductor device, and more particularly to an etching method when an antireflection film is used in semiconductor manufacturing.

[0002]

2. Description of the Related Art As systems using integrated circuits are miniaturized, it becomes difficult to accurately transfer a complicated circuit onto a chip having a small size by a lithography method.

[0003] The reason for this is that exposure is non-uniform, such as halation of light passing through the resist film due to the influence of non-uniform steps on the substrate.
As a result, a large number of defects and dimensional variations occur in the resist pattern formed by the lithography method.

As a method of reducing such non-uniform reflected light, for example, a method of forming an antireflection film under a resist film has been adopted.

Hereinafter, a method for etching a semiconductor device provided with an anti-reflection film in the prior art will be described with reference to the drawings.

FIG. 4 is an explanatory view of an etching method when an antireflection film according to the prior art is used.

In FIG. 1, reference numeral 1 denotes a semiconductor substrate, 2 denotes a film, 3 denotes an antireflection film, and 4 denotes a resist pattern.

As shown in FIG. 4A, an antireflection film 3 is formed on a film 2 formed on a semiconductor substrate 1,
Further, a resist pattern 4 is formed on the antireflection film 3.

The method of forming the resist pattern 4 includes a step of forming a normal resist film and a step of forming a light or electron beam or X-ray.
It comprises a step of irradiating a line and a step of removing an unnecessary portion of the resist film.

In FIG. 4A, an antireflection film 3 is formed on a film 2.
Is formed, it is possible to prevent the light passing through the resist film 4 from being uneven due to the influence of the reflection of light from the film formation 2. Therefore, the resist pattern 4 is formed with high dimensional accuracy.

Next, as shown in FIG. 4 (b), the anti-reflection film 3 and the film 2 are removed by dry etching from the portion where the resist pattern 4 is not formed.

[0012]

However, in the conventional method, when an organic material is used as the antireflection film 3,
Since the anti-reflection film 3 is made of an organic material similar to the resist pattern 4 formed on the anti-reflection film 3 (for example, the anti-reflection film 3 is made of polysalcon and the resist pattern 4 is made of novolak resin), the etching rates are mutually different. It is an approximate value.

For this reason, when the antireflection film 3 is removed by etching the portion where the resist pattern 4 is not formed, the resist pattern 4 is also etched at the same time, and the film is reduced.

Then, from this state, the film formation 2
When the resist pattern 4 is etched, the resist pattern 4 is also etched at the same time.
Cannot be left in a healthy state, and the symbol A in FIG.
As shown in FIG. 2, the film 2 is excessively shaved off, causing dimensional fluctuations of the circuit pattern, and the required quality and characteristics cannot be obtained.

Further, conventionally, since the step of etching the antireflection film 3 and the step of etching the film 2 are performed separately, the process from the formation of the resist pattern 4 to the etching of the film 2 is performed. Takes a long time,
Processing capacity was reduced.

In addition, since the etching of the antireflection film 3 requires a dedicated device, there is a problem that the running cost is high.

SUMMARY OF THE INVENTION In view of the above problems, the present invention reduces the film loss of a resist pattern during film formation etching so that a circuit can be transferred with high precision, quality can be improved, and running costs can be reduced. The task is to

[0018]

The present invention has the following features to solve the above-mentioned problems.

That is, in the method of etching a semiconductor device provided with an antireflection film according to the present invention, the resist pattern and the antireflection film are irradiated with visible light or far-sight rays after the step of etching the antireflection film. It is characterized by:

Further, after the step of etching the antireflection film, the resist pattern and the antireflection film are irradiated with visible light or far-sighted rays, and then the semiconductor substrate is subjected to a heat treatment.

A step of etching the anti-reflection film in the same apparatus, and a step of irradiating the resist pattern and the anti-reflection film with visible light or far-sighted radiation.
It is characterized in that the etching step is performed using the same single gas or a plurality of gases of the same type and the same mixture ratio as in the step of etching the antireflection film.

In the above-described method for etching a semiconductor device provided with an antireflection film, even in the step of etching the film, etching with excellent dimensional control is performed by reducing the loss and deformation of the resist pattern. be able to.

Further, the ability to perform processing per unit time from resist pattern formation to film formation etching can be improved. Furthermore, a dedicated device for performing anti-reflection film etching can be omitted.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for etching a semiconductor device according to the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is an explanatory diagram showing an etching method in a semiconductor device provided with an antireflection film according to Embodiment 1 in the order of steps.

In the figure, 1 is a semiconductor substrate, 2 is a film, 3 is an antireflection film, 4 is a resist pattern, 5 is visible light or far ultraviolet light.

The above-mentioned resist pattern 4 and antireflection film 3
Are made of organic materials, and specific examples include common resins such as novolak resins, vinyl resins represented by polyvinyl alcohol, acrylic resins represented by polymethyl methacrylate, and polyvinyl phenol derivatives. Organic materials are applied. In addition, Al-Si, A
A metal alloy such as l-Si-Cu is used.

In the manufacturing process, first, as shown in FIG. 1A, an antireflection film 3 is formed on a film 2 provided on a semiconductor substrate 1, and further, A resist pattern 4 is formed on the upper part.

The method of forming the resist pattern 4 includes a step of forming a normal resist film and a step of forming a light or electron beam or X-ray.
It comprises a photosensitive step of irradiating rays and a developing step of removing unnecessary portions of the resist film.

In FIG. 1A, since the antireflection film 3 is formed, uneven light passing through the resist film under the influence of the shape of the film 2 is prevented. Therefore, the resist pattern 4 is formed with high dimensional accuracy.

Next, as shown in FIG. 1B, the portion of the antireflection film 3 where the resist pattern 4 is not formed is removed by etching. At this time, the resist pattern 4 is also etched to some extent, as in the related art, so that the film is reduced.

Therefore, in the first embodiment, subsequently, as shown in FIG. 1C, the resist pattern 4 and the antireflection film 3 are irradiated with visible light or far ultraviolet rays 5.
By this step, the resist pattern 4 and the antireflection film 3 have improved resistance to etching due to a photoreaction.

In the next step, as shown in FIG. 1D, the film 2 is etched. In the etching step of the film formation 2, the resistance of the resist pattern 4 is increased.
Since the film loss can be reduced as compared with the conventional case, it is possible to perform etching with excellent dimensional controllability.

When light irradiation is performed in the step of FIG. 1A, that is, when the anti-reflection film 3 remains, the thickness of the anti-reflection film 3 is generally larger than the thickness of the resist pattern 4. For the same irradiation dose, the anti-reflection film 3 has a higher resistance to etching than the resist pattern 4 because of the same irradiation amount, so that it takes extra time to etch the anti-reflection film 3 and the resist pattern 4 The resistance cannot be improved.

On the other hand, if the resist pattern 4 is irradiated with light after removing the anti-reflection film 3 as shown in FIG. 1B, no extra time is required for etching the anti-reflection film 3. In addition, since the resistance of the resist pattern 4 to etching is improved, the reduction in the thickness of the resist pattern 4 can be advantageously reduced.

Further, in the first embodiment, FIG.
After the step of irradiating the resist pattern 4 and the anti-reflection film 2 with visible light or far ultraviolet rays 5 shown in (c), a step of performing a heat treatment 6 on the semiconductor substrate 1 as shown in FIG. 2 can be inserted. .

That is, as shown in FIG. 1C, when the resist pattern 4 and the antireflection film 3 are irradiated with visible light or far ultraviolet rays 5 after the step of etching the antireflection film 3, the resist pattern Although the antireflection film 4 and the antireflection film 3 not only improve the resistance to etching than the photoreaction but also improve the heat resistance to some extent, as shown in FIG. 2, if the treatment 6 for actively heating the semiconductor substrate 1 is performed,
In the next step shown in FIG. 1 (d), even if the semiconductor substrate 1 is heated when, for example, the film formation 2 is dry-etched, the resist pattern 4 is not thermally deformed and the dimensional controllability is further improved. Excellent etching can be performed.

(Embodiment 2) FIG. 3 is an explanatory view showing an etching method in a semiconductor device provided with an antireflection film according to Embodiment 2 in the order of steps.

In these figures, 7 is a chamber of the etching apparatus, 8 is an etching gas, and 9 is a plasma wave or a microwave. As an etching method in the second embodiment, for example, reactive ion etching for generating a plasma wave is applied.

First, as shown in FIG. 3 (a), an etching gas 8 is supplied into a chamber 7 to generate a plasma wave or a microwave 9 so that a resist pattern 4 is formed.
The anti-reflection film 3 in the area where no is formed is removed by etching. Etching gas 8 used in that case
Is a mixture of gases of a single component or a plurality of components at a predetermined mixing ratio. As an example, Cl ₂
The system gas is used.

Subsequently, when the generation of the plasma wave or the microwave 9 is stopped, the etching of the antireflection film 3 is stopped. In this case, the etching gas 8 supplied in the step of FIG. 3A is not removed and is left in the chamber 7 as it is.

In this state, next, as shown in FIG. 3B, the resist pattern 4 and the antireflection film 3 are irradiated with visible light or far ultraviolet rays 5 in the chamber 7 so that the resist pattern 4 is exposed. Improve the tolerance of.

Subsequently, as shown in FIG. 3C, the same etching gas 8 used in the step of FIG.
The film 2 is supplied again to generate plasma waves or microwaves 9 to etch the film formation 2.

As described above, in the second embodiment, FIG.
Since a series of steps (a) to (c) can be performed in the same chamber 7, there is no need to remove or reset the semiconductor device from the chamber 7. There is no need to exchange the etching gas 9.

Therefore, the processing ability per unit time from the resist pattern 4 to the etching of the film formation 2 can be improved. Further, an apparatus for etching the antireflection film 3 and an apparatus for etching the film formation 2 can be used in common.

The present invention is applicable to each of the first and second embodiments.
However, the present invention is not limited to this case, and can be widely applied to any semiconductor device provided with an antireflection film.

[0047]

According to the present invention, the following effects can be obtained.

(1) In the step of etching a film, the film thickness and deformation of the resist pattern can be reduced, so that etching with excellent dimensional control can be performed, and the quality can be improved. it can.

(2) Since the processing performance per unit time from the formation of the resist pattern to the etching of the film is improved, the productivity can be improved.

(3) A dedicated device for etching the antireflection film can be omitted, and the running cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a method of etching a semiconductor device according to a first embodiment of the present invention in the order of steps;

FIG. 2 is a process cross-sectional view showing a method for further improving the etching method of Embodiment 1 of the present invention shown in FIG. 1;

FIG. 3 is a sectional view showing a method of etching a semiconductor device according to a second embodiment of the present invention in the order of steps;

FIG. 4 is a sectional view showing a conventional method for etching a semiconductor device in the order of steps;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Film formation 3 Anti-reflection film 4 Resist pattern 5 Visible light or far ultraviolet rays 6 Heat treatment 7 Chamber 8 Etching gas 9 Plasma wave or microwave

Claims (3)

[Claims] A step of etching an anti-reflection film formed on the semiconductor substrate; and irradiating a resist pattern formed on the anti-reflection film and the anti-reflection film with visible light or far-sight rays. And a step of etching a film formed on the semiconductor substrate. A step of etching the anti-reflection film formed on the semiconductor substrate; and a step of etching the resist pattern formed on the anti-reflection film.
Irradiating the visible light or the far-sight ray to the anti-reflection film and the antireflection film; performing a heat treatment on the semiconductor substrate; and etching the film formed on the semiconductor substrate. Etching method. A step of etching the antireflection film formed on the semiconductor substrate in the same etching apparatus; and a step of etching the resist pattern formed on the antireflection film.
Irradiating the visible light or the far-sight ray to the anti-reflection film and etching the film formed on the semiconductor substrate to etch the anti-reflection film formed on the semiconductor substrate. And etching using the same single gas or a plurality of gases of the same type and the same mixture ratio.