JP2002305181A - Method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device, improving the controllability of a dimension and a shape of a workpiece, after etching by suppressing a cutting amount of a resist pattern at the time of etching. SOLUTION: The method for manufacturing a semiconductor device comprises a step of coating a resist film on a metal film 2, a step of forming resist patterns 3a, 3b on the metal film by exposing and developing the resist films, a step of forming cured layers 4 on the surfaces and side faces of the resist patterns by plasma processing by a gas containing a fluorine in the patterns, and a step of dry etching the film 2 with the patterns 3a, 3b as masks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device having a patterning step. in particular,
The present invention relates to a method for manufacturing a semiconductor device having improved controllability of the size and shape of a workpiece after etching.

[0002]

2. Description of the Related Art FIGS. 2A and 2B are cross-sectional views showing a conventional method for manufacturing a semiconductor device. This method of manufacturing a semiconductor device includes a step of patterning a metal film or the like.

[0003] First, as shown in FIG.
A metal film 12 such as an Al alloy film or a MoSi film is deposited on 1 by a sputtering method. Next, a resist film is applied on the metal film 12, and the resist film is exposed and developed to form a resist pattern 13a on the metal film 12.
13b is formed. Thereafter, as shown in FIG. 2B, the metal film 12 is dry-etched with a chlorine-based gas using the resist patterns 13a and 13b as a mask. Thus, the wiring patterns 12a and 12b made of a metal film are formed on the insulating film 11.

[0004]

As described above, in the conventional method for manufacturing a semiconductor device, a metal film such as an Al alloy film or a MoSi film, which is a workpiece, is etched with a chlorine-based gas. As shown in (b), the amount of scraping of the resist patterns 13a and 13b becomes relatively large. Therefore, as shown in FIG. 2A, it is necessary to increase the thickness of the resist pattern in order to secure a margin for the remaining resist film. That is, it is necessary to form the resist pattern thicker in consideration of the amount of the resist pattern removed during etching.

However, as the thickness of the resist pattern increases, the controllability of the size and shape of the resist pattern deteriorates. Therefore, when the metal film is finely etched, it is disadvantageous to increase the thickness of the resist pattern. In other words, if the thickness of the resist pattern is increased, it becomes difficult to finely etch the metal film.

[0006] When both dry etching and wet etching are performed using a resist pattern as a mask, a descum treatment using O ₂ plasma may be performed before the wet etching. This is to make the resist pattern thinner to control the etching dimension and to improve the wet etching solution. When the Descam process is performed, the thickness of the resist becomes thinner. In this respect, the resist pattern also tends to be thicker.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to control the size and shape of a workpiece after etching by suppressing the amount of removal of a resist pattern during etching. It is an object of the present invention to provide a method for manufacturing a semiconductor device with improved reliability.

[0008]

In order to solve the above-mentioned problems, a method for manufacturing a semiconductor device according to the present invention comprises a step of applying a resist film on an etching film, and exposing and developing the resist film. A step of forming a resist pattern on the etching film, a step of forming a hardened layer on the surface and side surfaces of the resist pattern by subjecting the resist pattern to plasma treatment with a gas containing fluorine, and using the resist pattern as a mask Dry-etching the etching film.

According to the method of manufacturing a semiconductor device, the resist pattern is subjected to plasma treatment with a gas containing fluorine to form a hardened layer on the surface and side surfaces, thereby improving the dry etching resistance of the resist pattern. it can. That is, the resist can be hardly removed at the time of etching, and as a result, the margin of the remaining resist film can be increased. Therefore, by reducing the thickness of the resist pattern, it is possible to improve the controllability of the size and shape of the workpiece after the etching in the step of dry-etching the etching film.

In the method for manufacturing a semiconductor device according to the present invention, the gas containing fluorine may be a mixed gas obtained by adding 5% to 30% of CHF ₃ gas or CF ₄ gas to O ₂ gas. preferable.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1A to 1C are cross-sectional views illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present invention. The method of manufacturing the semiconductor device is as follows.
It has a step of patterning a metal film or the like.

First, as shown in FIG.
A metal film 2 such as an Al alloy film or a MoSi film is deposited thereon by a sputtering method. Next, a resist film is applied on the metal film 2, and the resist film is exposed and developed, whereby resist patterns 3a and 3b are formed on the metal film 2.

Thereafter, as shown in FIG.
By subjecting the resist patterns 3a and 3b to plasma treatment with a fluorine-containing gas such as F ₄ and CHF ₃ , a cured layer 4 is formed on the surfaces and side surfaces of the resist patterns 3a and 3b.
Is formed.

That is, for example, a mixed gas obtained by adding 10% of CHF ₃ gas to O ₂ gas is flowed over the surfaces of the resist patterns 3a and 3b at a flow rate of 100 sccm to perform a plasma treatment for 10 seconds. Thereby, the resist patterns 3a, 3
A hardened layer 4 is formed on the surface and side surfaces of b. At this time,
Since the dimensions of the resist patterns 3a and 3b are smaller than those in the case where only O ₂ gas is flown, and their shapes do not change,
It hardly affects the size and shape of the workpiece (wiring pattern) to be etched in the subsequent process. In addition,
The hardened layer is formed by reacting components such as carbon, hydrogen and oxygen contained in the resist with fluorine in the gas.

Next, as shown in FIG. 1C, the metal film 2 is dry-etched with a chlorine-based gas using the resist patterns 3a and 3b as a mask, so that a wiring made of the metal film is formed on the insulating film 1. Patterns 2a and 2b are formed. At this time, since the hardened layer 4 is formed on the surfaces and side surfaces of the resist patterns 3a and 3b, the amount of the resist removed is approximately half as compared with the conventional resist.

Thereafter, the resist patterns 3a and 3b are subjected to plasma stripping and wet stripping to remove the resist patterns (not shown).

According to the first embodiment, the resist pattern 3a, 3b is subjected to plasma treatment with a gas containing fluorine to form the hardened layer 4 on the surface and the side surface, so that the resist pattern has a dry etching resistance. Can be improved. This makes it difficult to remove the resist at the time of etching. As a result, the margin of the remaining resist film can be increased. In other words, a sufficient margin of the remaining resist film can be ensured even if the thickness of the resist patterns 3a and 3b is made thinner than the conventional one. Therefore, by reducing the thickness of the resist pattern, the controllability of the dimensions and shape of the wiring patterns 2a and 2b can be improved. Further, the thickness of the resist pattern can be reduced, which is advantageous for fine etching.

Next, a method of manufacturing a semiconductor device according to a second embodiment of the present invention will be described. The description of the same parts as in the first embodiment is omitted, and the description focuses on the different parts. I do.

Plasma treatment is performed on the resist patterns 3a and 3b.
The mixed gas used for the treatment is _TwoCHF for gas_Threegas
Is added to 30% of the mixed gas. That is, O_TwoC for gas
HF_Three30% gas mixture and resist pattern
Flow at a flow rate of 100 sccm on the surfaces of 3a and 3b to 10
A plasma treatment is applied for a second. As a result, the resist pattern
Cured layers 4 are formed on the surfaces and side surfaces of the layers 3a and 3b.
And the size of the resist pattern is about 0.03 μm
Can be thin.

In the second embodiment, the same effects as in the first embodiment can be obtained.

Further, in the second embodiment, the amount of CHF ₃ gas to be added is larger than that in the first embodiment, so that the resist pattern after the plasma processing is larger than the resist pattern before the plasma processing. Can be reduced in size. This is due to the mixing ratio of O ₂ gas and CHF ₃ gas. Therefore, by controlling the mixing ratio, the dimension of the resist pattern can be adjusted, and the controllability of the etching dimension can be further improved.

It should be noted that the present invention is not limited to the above embodiment, but can be implemented with various modifications without departing from the gist of the present invention. For example, in the first and second embodiments, the present invention is used in the step of patterning a metal film, but the present invention may be used in the step of patterning a conductive film or an insulating film made of another material. It is possible.

In the first and second embodiments, a mixed gas obtained by adding CHF ₃ gas to O ₂ gas is used as the gas containing fluorine. However, CF ₂ is used as the gas containing fluorine. It is also possible to use a mixed gas to which _four gases are added.

In the first embodiment, a mixed gas obtained by adding 10% of CHF ₃ gas to O ₂ gas is used as the gas containing fluorine. However, the mixing ratio of CHF ₃ gas is 5% to 5%. If it is 30%, it can be changed to another ratio as appropriate.

[0025]

As described above, according to the present invention, a hardened layer is formed on the surface and side surfaces by subjecting a resist pattern to plasma treatment with a gas containing fluorine. Therefore, the amount of removal of the resist pattern at the time of etching can be suppressed, whereby the controllability of the size and shape of the workpiece after the etching can be improved.

[Brief description of the drawings]

FIGS. 1A to 1C are cross-sectional views illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views illustrating a conventional method for manufacturing a semiconductor device.

[Explanation of symbols]

 1, 11: insulating film 2, 12: metal film 2a, 2b, 12a, 12b: wiring pattern 3a, 3b, 13a, 13b: resist pattern 4: cured layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5F004 AA04 CA02 DA01 DA16 DA26 DA30 DB09 DB18 EA04 5F033 HH09 HH29 QQ00 QQ01 QQ08 QQ11 QQ26 XX00

Claims (2)

[Claims] A step of applying a resist film on the etching film; a step of exposing and developing the resist film to form a resist pattern on the etching film; A method for manufacturing a semiconductor device, comprising: a step of forming a hardened layer on a surface and a side surface of a resist pattern by performing a plasma treatment; and a step of dry-etching an etching film using the resist pattern as a mask. . 2. A gas containing the fluorine may 5 O ₂ gas
2. The method according to claim 1, wherein the mixed gas is a mixture of CHF ₃ gas or CF ₄ gas of not less than 30% and not more than 30%.