KR100390912B1 - Method for forming contact hole of semiconductor device - Google Patents

Abstract

The present invention discloses a method of forming a contact hole having a fine size by changing an etching barrier and forming a spacer, and the method of forming a contact hole according to the present invention includes an interlayer insulating film on a silicon substrate having a predetermined underlayer on top. Sequentially forming a first inorganic film and a photosensitive film; Exposing and developing the photoresist to form a photoresist pattern defining a contact hole formation region; Etching the first inorganic layer by an etching process using the photoresist pattern as an etching barrier to form a first inorganic layer pattern; Removing the photoresist pattern; Forming a second inorganic film on the interlayer insulating film including the first inorganic film pattern; Etching the second inorganic film to form spacers on both sidewalls of the first inorganic film pattern; And etching the interlayer insulating layer by using the first inorganic layer pattern having spacers on both sidewalls as an etching barrier to form contact holes having a fine size. Here, the method of the present invention uses a silicon nitride film (SiN), or a silicon nitride oxide film (SiON) as the material of the first inorganic film and the second inorganic film, and the size of the contact hole is deposited on the second inorganic film In addition, the contact hole is formed such that its top portion has a relatively large size.

Description

Method for forming contact hole in semiconductor device {METHOD FOR FORMING CONTACT HOLE OF SEMICONDUCTOR DEVICE}

The present invention relates to a method of forming a contact hole in a semiconductor device, and more particularly, to a method of forming a contact hole having a fine size by changing an etching barrier and forming a spacer.

In recent years, with the progress of semiconductor manufacturing technology, high integration of semiconductor devices has been rapidly progressed, and the necessity of miniaturization and high precision of patterns formed on substrates is increasing.

Accordingly, the size of the contact hole, which is an electrical connection path between the lower conductive pattern and the upper conductive pattern, is also required to be miniaturized, and therefore, many techniques for reducing the size of the contact hole have been researched and developed.

In this case, in order to form the contact hole, a lithography process of etching a lower layer thin film using a photosensitive film as an etching barrier is applied in a conventional semiconductor manufacturing process.

That is, in the prior art, the photoresist pattern is formed on the etching target layer through application, exposure and development of the photoresist layer, and the etching target layer is etched using the photoresist pattern as an etching barrier to form a contact hole. do.

However, there is a difficulty in forming a contact hole having a fine size by the above method. That is, the photoresist pattern used as an etching barrier is formed through the application, exposure and development of the photoresist. At this time, since the critical dimension of the pattern that can be implemented by the existing exposure equipment is limited, the micro contact having a size smaller than or equal to the critical dimension The hole is difficult to be formed only by the above-described method.

Therefore, in the related art, when the photoresist film is exposed, a phase shift mask is applied to increase the resolution, the resolution is improved by changing the material of the photoresist film, or a method of lowering the thickness of the photoresist film is applied. It is possible to form contact holes.

However, even if the above-described methods are applied, it is difficult to form contact holes having a fine size in the conventional method.

That is, in the method of applying the phase inversion mask, it is difficult to maintain the duty ratio of the contact hole due to the high integration of the device, so that the unwanted portion is vulnerable to the sidelobe to which the unwanted portion is exposed. It is difficult to secure process margins when forming contact holes.

The method of applying the material change of the photoresist film not only takes a lot of time and effort to test the application of the modified photoresist film, but also is difficult to apply to production.

In addition, the method of lowering the thickness of the photoresist film is good in terms of resolution, but shows a limitation in function as an etching barrier in a subsequent etching process.

Accordingly, an object of the present invention is to provide a method for forming a contact hole in a semiconductor device in which a contact hole having a fine size can be formed by changing an etching barrier and forming a spacer. have.

1A to 1E are cross-sectional views for each process for describing a method for forming a fine contact hole according to an exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

1 silicon substrate 2 interlayer insulating film

3: first inorganic film 3a: first inorganic film pattern

4: photosensitive film 4a: photosensitive film pattern

5 spacer 10 exposure mask

20: fine contact hole

In order to achieve the above object, a method of forming a contact hole in a semiconductor device according to the present invention includes: sequentially forming an interlayer insulating film, a first inorganic film, and a photoresist film on a silicon substrate having a predetermined underlayer thereon; Exposing and developing the photoresist to form a photoresist pattern defining a contact hole formation region; Etching the first inorganic layer by an etching process using the photoresist pattern as an etching barrier to form a first inorganic layer pattern; Removing the photoresist pattern; Forming a second inorganic film on the interlayer insulating film including the first inorganic film pattern; Etching the second inorganic film to form spacers on both sidewalls of the first inorganic film pattern; And etching the interlayer insulating layer by using the first inorganic layer pattern having spacers on both sidewalls as an etching barrier to form contact holes having a fine size.

Here, the method of the present invention uses a silicon nitride film (SiN) or a silicon nitride oxide film (SiON) as the material of the first inorganic film and the second inorganic film.

In addition, the method of the present invention adjusts the size of the contact hole to the deposition thickness of the second inorganic film, the contact hole is formed so that the top portion thereof has a relatively large size.

According to the present invention, by changing the etching barrier to an inorganic film instead of the conventional photoresist film, and by forming a spacer on the sidewall of the patterned inorganic film, it is possible to easily form a contact hole of a finer size.

(Example)

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A to 1G are cross-sectional views illustrating processes for forming a contact hole in a semiconductor device according to an exemplary embodiment of the present invention.

First, as shown in FIG. 1A, in a state where a predetermined base layer (not shown) is formed on the silicon substrate 1, a silicon oxide film is formed on the entire surface of the silicon substrate 1 to cover the base layer. The interlayer insulating film 2 thus formed is formed, and the surface thereof is planarized. Then, the first inorganic film 3 is deposited to a predetermined thickness on the interlayer insulating film 2, and the photosensitive film 4 is coated on the first inorganic film 3. Subsequently, the photosensitive film 4 is exposed to light using the exposure mask 10.

In this case, the first inorganic film 3 is to be used as an etch barrier later, and is preferably formed of a silicon nitride film (SiN) or a silicon nitride oxide film (SiON).

Next, a development process is performed on the exposed photoresist film to form a photoresist pattern 4a on the first inorganic film 3 as shown in FIG. 1B, and then the photoresist pattern 4a is etched. The first inorganic layer portions are exposed by etching to form a first inorganic layer pattern 3a.

Next, in a state in which the photoresist pattern used as the etching barrier is removed, a second inorganic material made of silicon nitride (SiN) or silicon nitride oxide (SiON) on the interlayer insulating film 2 including the first inorganic film pattern 3a. A film is deposited and then the second inorganic film is blanket etched to form spacers 5 on both sidewalls of the first inorganic film pattern 3a, as shown in FIG. 1C. At this time, the deposition thickness of the second inorganic film is adjusted in consideration of the size of the contact hole to be finally obtained.

Subsequently, as shown in FIG. 1D, the exposed portion of the interlayer insulating layer is etched using the first inorganic pattern 3a including the spacer 5 as an etching barrier, and thereby, the interlayer insulating layer 2 is etched. The micro contact hole 20 exposing a predetermined portion of the substrate 1 is formed. In this case, when the fine contact hole 20 is formed, the width of the top portion thereof is relatively wide, so that the step coverage characteristic may be improved at the time of subsequent embedding of the conductive film. .

Thereafter, as shown in FIG. 1E, the first inorganic pattern including the spacer used as the etching barrier is removed, and a known subsequent process is performed.

In the method of forming a fine contact hole of the present invention as described above, as shown in FIG. 1B, the size of the contact hole formed by the photosensitive film is “a”, but as shown in FIG. 1E, the contact hole finally obtained is shown. The size becomes about "b" which is relatively smaller than "a".

Therefore, by applying the method of the present invention, it is possible to easily and reproducibly form a fine contact hole having a size below a critical dimension that can be realized with existing photoresist and exposure equipment.

In addition, since the fine contact hole can be formed without using a phase inversion mask for forming the fine contact hole or applying a material change of the photoresist film and a reduction in the thickness of the photoresist film, there are other problems due to the application of the above methods. It can fundamentally solve the occurrence.

In particular, the method of the present invention can form a contact hole of a desired size by adjusting the deposition thickness of the second inorganic film, and the thickness of the interlayer insulating film to which the respective deposition thicknesses of the first inorganic film and the second inorganic film should be etched. By optimizing according to this, it is possible to prevent the occurrence of a functional limit as an etching barrier.

As described above, the method of the present invention changes the etching barrier for forming the fine contact hole into an inorganic film instead of a conventional photoresist film, and also forms a spacer on the sidewall of the patterned inorganic film, thereby forming a fine contact hole. It can be formed easily and reproducibly, and therefore, the method of the present invention can implement a pattern below a critical dimension that can be implemented by existing exposure equipment, and thus can be very advantageously applied to the fabrication of highly integrated devices.

In addition, this invention can be implemented in various changes in the range which does not deviate from the summary.

Claims (5)

Sequentially forming an interlayer insulating film, a first inorganic film, and a photoresist film on a silicon substrate having a predetermined base layer thereon; Exposing and developing the photoresist to form a photoresist pattern defining a contact hole formation region; Etching the first inorganic layer by an etching process using the photoresist pattern as an etching barrier to form a first inorganic layer pattern; Removing the photoresist pattern; Forming a second inorganic film on the interlayer insulating film including the first inorganic film pattern; Etching the second inorganic film to form spacers on both sidewalls of the first inorganic film pattern; And forming a contact hole having a fine size by etching the interlayer insulating layer by an etching process using the first inorganic layer pattern having spacers on both sidewalls as an etching barrier. The method of claim 1, wherein the first inorganic film and the second inorganic film A silicon nitride film (SiN) or a silicon nitride oxide film (SiON). The method of claim 2, wherein the first inorganic film and the second inorganic film A contact hole forming method of a semiconductor device, characterized in that the same material or made of a different material. The method of claim 1, wherein the size of the contact hole is controlled by a deposition thickness of the second inorganic layer. The method of claim 1, wherein the contact hole is formed such that its top portion has a relatively large size.