JPH07169683A - Semiconductor device with antireflection film and its manufacture - Google Patents

Abstract

PURPOSE:To reduce reflection from a high reflection film under an insulation film in a photolithography process carried out for shaping a contact hole in an insulation film and to transfer a pattern which is faithful to a mask to resist by forming an antireflection film on an insulation film. CONSTITUTION:A first aluminum film 11 having a reflecting of 50% or more to exposure light in a first photolithography process is formed on a device layer 10. A first antireflection film 12 having a reflectivity of 30% or more to exposure light in the first photolithography process is formed on the first aluminum film 11. After the first antireflection film 12 is removed, a layer insulation film 13 having a transmissivity of 60% or more to exposure light in a second photolithography process is deposited. A second antireflecting film 14 having a reflecting of 30% or less to exposure light in the second photolithography process is formed on the layer insulation film 13. Thereby, a pattern faithful to a mask can be transferred to photoresist.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a highly reflective film deposited under an insulating film.

[0002]

2. Description of the Related Art When opening a contact hole in an insulating film formed on a highly reflective film, a photoresist is applied on the insulating film and a mask pattern is transferred to the photoresist by a photolithography technique. It was formed by patterning the photoresist and etching the insulating film using the photoresist as a mask.

[0003]

According to the above method, when the photoresist on the insulating film is patterned by the photolithography technique, the exposure light passes through the insulating film and is reflected by the highly reflective film under the insulating film. The light reflected from the high-reflectivity film exposes the resist, which should not be exposed, to a pattern that is not faithful to the mask.

[0004]

In order to solve these problems, the present invention has a reflectance of 50% or more on the substrate with respect to the exposure light in the first photolithography process which is the next process. A high reflectance thin film is formed, and a first antireflection film having a reflectance of 30% or less with respect to the exposure light in the first photolithography step is formed on the high reflectance thin film, The high reflectance thin film and the first antireflection film are selectively patterned through a photolithography process and an etching process, and then the first antireflection film is removed.

After removing the first antireflection film, an interlayer insulating film having a transmittance of 60% or more for exposure light is formed on the thin film having a high reflectance in the second photolithography process, and the interlayer insulating film is formed. A second antireflection film having a reflectance of 30% or less with respect to the exposure light in the second photolithography process is formed on the film, and the interlayer insulating film is patterned through the photolithography process and the etching process. It is the one.

[0006]

By providing the antireflection film on the insulating film, it is possible to reduce the light reflected from the highly reflective film below the insulating film in the photolithography process performed to open a contact hole in the insulating film. As a result, the photoresist is not exposed to the light reflected by the highly reflective film, and a pattern faithful to the mask can be formed on the photoresist.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In a semiconductor element in which the insulating film 2 is formed on the high reflection film 1, the insulating film 2
An antireflection film 3 is formed on top. In order to form an opening of a contact hole in the insulating film 2, a photoresist 4 is applied on the antireflection film 3 and then a photolithography technique is used.
The pattern of the mask 6 is transferred onto the photoresist 4.
At this time, the exposure light 7 is reflected by the high reflection film 1 under the insulating film 2 by the antireflection film 3 so that a pattern faithful to the mask 6 can be transferred to the photoresist without exposing the photoresist 4 to light. Become.

Detailed embodiments of the manufacturing method of the present invention will be described with reference to the drawings. FIG. 3 shows the manufacturing process of the present invention. A first aluminum film 11 is formed on the device layer 10 by using a sputtering method or the like. The first aluminum film is a highly reflective film having a reflectance of 50% or more with respect to the exposure light (g-line, i-line, excimer laser or X-ray) in the first photolithography process.

TiN is formed on the first aluminum film 11 as the first antireflection film 12 by using a sputtering method of 10 to 1000 liters. This first antireflection film 12
Is the exposure light (g-line,
30% for i-line, excimer laser or X-ray)
It is a film having the following reflectance.

A photoresist is applied on the first antireflection film 12 and exposed through a mask to selectively pattern the photoresist film. The first antireflection film 12 and the first aluminum film 11 are etched by using the patterned photoresist film as a mask. After the etching, the photoresist film is peeled off, and the first antireflection film 12 on the first aluminum film 11 is removed by etching the entire surface.

After removing the first antireflection film 12, the interlayer insulating film 13 is deposited by the CVD method or the like. The interlayer insulating film 13 is exposed to the exposure light (g
6 lines, i-line, excimer laser or X-ray)
A film having a transmittance of 0% or more, such as SiO ₂ , SiO
It is a film of N, PSG, BPSG or the like.

A second antireflection film 14 is formed on the interlayer insulating film 13.
Is formed by using a sputtering method or the like. The second antireflection film 14 is the second
Is a film having a reflectance of 30% or less with respect to the exposure light (g-line, i-line, excimer laser or X-ray) in the photolithography process.

A photoresist 15 is applied on the second antireflection film 14 and exposed through a mask 16 to selectively pattern the photoresist 15.
By using the patterned photoresist 15 as a mask, the second antireflection film 14 and the interlayer insulating film 13 are etched to selectively form an opening of a contact hole in the interlayer insulating film 13. After etching, the photoresist 15 on the second antireflection film 14 is removed.

A second aluminum film 19 is formed on the second antireflection film 14 by a sputtering method or the like. As the third antireflection film 20, T is formed on the second aluminum film.
iN is formed in the range of 10 to 1000Å. Third antireflection film 2
0 is coated with a photoresist and exposed through a mask to selectively pattern the photoresist film. The third antireflection film 20, the second aluminum film 19, and the second antireflection film 14 are etched using the patterned photoresist film as a mask. After etching, the photoresist is stripped.

As described above, in this embodiment, by providing the antireflection film 14 on the interlayer insulating film 13, the exposure light is transmitted through the interlayer insulating film 13 during the photolithography process and is reflected by the aluminum film below the interlayer insulating film 13. Then, a pattern faithful to the mask can be transferred to the photoresist without locally exposing the photoresist.

Further, in the present embodiment, the second antireflection film 14 on the interlayer insulating film 13 is simultaneously etched when the second aluminum film is etched. However, the second antireflection film 14 is an insulating film. If (α-Si or SiN) is used, there is no need for etching. Further, in this embodiment,
Although an aluminum film is used for explanation, this may be a polysilicon film or a silicide film.

[0017]

INDUSTRIAL APPLICABILITY As described above, the present invention forms an antireflection film on an insulating film to form a bottom surface of the insulating film in a photolithography process for forming a contact hole in the insulating film. 40 from the high reflection film of
%, It is possible to transfer a pattern faithful to the mask to the resist without exposing the resist where it should not be exposed by the reflected light from the high reflection film.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a semiconductor device showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional semiconductor device.

FIG. 3 is a diagram showing a manufacturing process of the present invention.

[Explanation of symbols]

1 High Reflection Film 2 Insulating Film 3 Antireflection Film 4,15 Photoresist 5 Photoresist Pattern Formed by Photolithography Technology 6,16 Mask 7,17 Exposure Light 8 Reflection Light from High Reflection Film 10 Device Layer 11 First Aluminum film 12 First antireflection film 13 Interlayer insulating film 14 Second antireflection film 18 Contact hole 19 Second aluminum film 20 Third antireflection film

Claims (3)

[Claims] 1. A step of forming a high reflectance thin film having a reflectance of 50% or more with respect to exposure light in a first photolithography step, which is a subsequent step, on the substrate, and the high reflectance. Forming a first antireflection film having a reflectance of 30% or less with respect to the exposure in the first photolithography process on the thin film, and forming a first antireflection film on the first antireflection film.
Forming a photoresist film, a first photolithography step of patterning the first photoresist film by selectively exposing the first photoresist film, and a patterning in the first photolithography step. The first
Etching the first antireflection film and the high reflectance thin film using the photoresist film as a mask; removing the first photoresist film and the first antireflection film; and the high reflectance A second photolithography step, which is the next step, on the thin film of 1) to form an interlayer insulating film having a transmittance of 60% or more with respect to exposure light; and the second photolithography step on the interlayer insulating film. A step of forming a second antireflection film having a reflectance of 30% or less with respect to exposure light in a lithography step, and a step of forming a second photosensitive film on the second antireflection film; A second photolithography step of patterning the second photosensitive film by selectively exposing the second photosensitive film; and the second antireflection film and the interlayer using the second photosensitive film as a mask. Etching the insulating film A method for manufacturing a semiconductor device comprising: 2. The method for manufacturing a semiconductor device according to claim 1, further comprising a step of removing the second antireflection film. 3. A first conductive film selectively formed on a substrate, an interlayer insulating film formed on the conductive film, and a part of the first conductive film via a contact hole of the interlayer insulating film. 1
And a second conductive film electrically connected to the conductive film, the interlayer insulating film is formed in at least a two-layer structure, and the uppermost film is made of TiN, α.
-A semiconductor device which is either Si or SiN.