KR19980083001A - Method for manufacturing contact hole of semiconductor device - Google Patents

Abstract

The present invention relates to a method for manufacturing a contact hole in a semiconductor device, and sequentially forming a first oxide film, an interlayer insulating film, and a second oxide film on a semiconductor substrate, and then using the photoresist pattern as a mask, the second oxide film is inclinedly etched to form a groove. After forming a carbon rich polymer in a predetermined thickness in the groove and anisotropically etched with oxygen plasma to form a carbon rich polymer spacer, and then isotropically etched it with an etch barrier and remove the carbon rich polymer spacer wine glass After forming a contact hole having a shape or forming an oxide film and a nitride film on the semiconductor substrate, a photoresist film pattern is formed, and a carbon rich polymer having a predetermined thickness is formed on the entire surface thereof, and then anisotropically etched with oxygen plasma to form a carbon rich polymer spacer. After forming, isotropically etch it with an etch barrier to form contact holes Type etching process alone can be formed with reproducibility the contact hole to a technique that can improve the reliability of the semiconductor device.

Description

Method for manufacturing contact hole of semiconductor device

The present invention relates to a method for manufacturing a contact hole of a semiconductor device, and in particular, by forming a contact hole in the shape of a wine glass using a carbon rich polymer or forming a contact hole using only a dry etching process without a wet etching process when forming a contact hole of a fine pattern. A technique for improving the reliability of a semiconductor device.

In general, the contact hole connecting the upper and lower conductive wirings in the semiconductor device is reduced in size and the distance between the peripheral wiring and the aspect ratio, which is the ratio of the diameter and the depth of the contact hole, is increased.

Therefore, in a highly integrated semiconductor device having multiple conductive wirings, accurate and tight alignment between masks in a manufacturing process is required to form a contact, thereby reducing process margin.

The contact hole has misalignment tolerance during mask alignment, lens distortion during exposure process, critical dimension variation during mask fabrication and photolithography process, and between masks to maintain gaps. The mask is formed by considering factors such as registration.

In addition, in order to overcome the limitations of the lithography process in forming the contact holes, a technology of forming a self-aligned contact hole (hereinafter referred to as SAC) has been developed.

Although not shown in the drawings, a method of manufacturing a wine glass contact hole according to the related art will be briefly described.

First, a first interlayer insulating film, a second interlayer insulating film, and a third interlayer insulating film are sequentially formed on a predetermined lower structure on a semiconductor substrate.

Next, a photoresist pattern is formed on the third interlayer insulating layer to expose a portion to form a contact hole through the lithography process.

Next, the third interlayer insulating film exposed by the photosensitive film pattern is isotropically etched to form a concave groove, and then the bottom of the groove is anisotropically etched to form a wine glass contact hole.

According to the prior art as described above, when forming the contact glass of the wine glass shape first proceeds the wet process using a BOE solution having an isotropic etching characteristic, and then proceeds to a dry process having an anisotropic etching characteristic to form a contact hole do.

However, in the wet process, when the adhesion between the photoresist pattern and the oxide layer is poor, etching may be severe or it may be difficult to constantly form an etching profile.

In addition, since the wet etching profile is changed according to the type of the oxide layer of the etched layer, there is a problem that may adversely affect the deposition of metal wiring in a subsequent process.

On the other hand, the formation of fine contact holes of 0.1 μm or less is patterned by a photoresist mask using an electron beam. Throughput is very low and there are many difficulties in commercialization.

In particular, when a polymer is used to form a contact hole, when the etching chamber is subjected to an impact to minimize the ion energy and deposit the polymer on the front surface of the wafer, a large amount of particles are generated, thereby reducing the ion energy and step coverage. Since the thickness of the polymer increases around the contact hole of the contact mask due to poor), it is difficult to control the size of the polymer spacer, and thus, there is a problem in that a process must be added.

Accordingly, the present invention is to solve the above problems to form an inclined groove in the oxide layer, and to form a carbon rich polymer of a predetermined thickness, and then anisotropically etched with oxygen plasma to form a carbon rich polymer spacer, the etching barrier Isotropically etched to remove the carbon-rich polymer spacers to form a wine glass-shaped contact hole, thereby replacing the wet etching process, thereby reducing additional costs, and using a dry etching process to form reproducible contact holes. It is an object of the present invention to provide a method for manufacturing a contact hole.

Another object is to form an oxide film and an interlayer insulating film on a semiconductor substrate, and then to form a photoresist pattern, a carbon rich polymer having a predetermined thickness on the entire surface thereof, and then anisotropically etch it with oxygen plasma to form a carbon rich polymer spacer. The purpose of the present invention is to provide a method for fabricating a semiconductor device in which a series of processes are performed in a batch by forming contact holes using the photoresist pattern and the carbon rich polymer spacer as etch barriers, thereby improving reliability of the semiconductor device. have.

1A to 1E are diagrams illustrating a manufacturing process of a contact hole in a semiconductor device according to an embodiment of the present invention.

2A to 2D are diagrams illustrating a manufacturing process of a contact hole in a semiconductor device according to another embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

11, 31: semiconductor substrate 13, 33: first oxide film

15, 35: interlayer insulating film 17: second oxide film

19, 37: photoresist pattern 21, 39: carbon rich polymer

23, 41: carbon rich polymer spacer 25, 43: contact hole

Contact hole manufacturing method of a semiconductor device according to an embodiment of the present invention to achieve the above object;

Sequentially forming a first oxide film, an interlayer insulating film, and a second oxide film on the semiconductor substrate;

Forming a contact photoresist pattern on the second oxide film;

Dry etching the photoresist pattern with a mask to form a second oxide film inclined, but forming a second oxide film pattern exposing a contact portion surface of the interlayer insulating film;

Forming a carbon rich polymer on the entire surface of the structure;

Anisotropically etching the carbon rich polymer with oxygen plasma to form a carbon rich polymer spacer on the sidewalls of the second oxide film pattern;

And forming a contact hole by using the photoresist pattern and the carbon rich spacer as an etch barrier until the semiconductor substrate is exposed.

In addition, the contact hole manufacturing method of a semiconductor device according to another embodiment of the present invention;

Sequentially forming an oxide film and an interlayer insulating film on the semiconductor substrate;

Forming a contact photoresist pattern on the interlayer insulating film;

Forming a carbon rich polymer on the entire surface of the structure;

Anisotropically etching the carbon rich polymer to form a carbon rich polymer spacer on the sidewalls of the photoresist pattern;

And forming a contact hole by using the photoresist pattern and the carbon rich spacer as an etch barrier until the semiconductor substrate is exposed.

Hereinafter, a method for manufacturing a contact hole of a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings.

1A to 1E are diagrams illustrating a process of manufacturing a contact hole in a semiconductor device according to an embodiment of the present invention.

First, predetermined lower structures (not shown) are formed on the semiconductor substrate 11, for example, an element isolation oxide film, a MOS field effect transistor, a bit line, a capacitor, and the like, and then a first oxide film 13 and an interlayer insulating film. 15 and the second oxide film 17 are sequentially formed.

In this case, the interlayer insulating film 15 may be formed of a nitride film or an oxide film containing a large amount of nitrogen.

Next, a photosensitive film pattern 19 is formed on a portion of the interlayer insulating film 15 to be contacted (see FIG. 1A).

Then, the photoresist layer pattern 19 is etched in an inclined manner with a mask, and the photoresist layer pattern 19 is etched so that the contact portion of the interlayer insulating layer 15 is exposed.

Next, the carbon rich polymer 21 composed of carbon (C) / flowlin (F) is formed to a predetermined thickness on the entire surface of the structure.

At this time, the carbon rich polymer 21 has a high composition ratio of carbon (see FIG. 1C).

Next, the carbon rich polymer 21 is anisotropically etched with oxygen plasma to form carbon rich polymer spacers 23 on sidewalls of the photoresist pattern 19 and the second oxide layer 17.

At this time, the contact portion of the interlayer insulating film 15 is exposed (see FIG. 1D).

Next, using the carbon rich polymer spacers 23 formed on the sidewalls of the photoresist pattern 19 and the second oxide layer 17 as sidewall barriers, the etch selectivity of the interlayer insulating layer 15 and the first oxide layer 13 is 1. Etching at a ratio of 1 to form a wine glass-shaped contact hole 25.

Then, the photoresist film 19 and the carbon rich polymer spacer 23 remaining in the contact hole 25 are removed by isotropic etching using oxygen plasma (see FIG. 1E).

2A to 2D are diagrams illustrating a process of manufacturing a contact hole in a semiconductor device according to another exemplary embodiment of the present invention.

First, predetermined lower structures (not shown) are formed on the semiconductor substrate 31, for example, an element isolation oxide film, a MOS field effect transistor, a bit line, a capacitor, and the like, and then a first oxide film 33 and an interlayer insulating film. (35) is formed sequentially.

At this time, the interlayer insulating film 35 is formed of a nitride film or an oxide film containing a large amount of nitrogen.

Next, a photosensitive film pattern 37 is formed on a portion of the interlayer insulating film 35 that is intended to be a contact. (See FIG. 2A).

Next, a carbon rich polymer 39 composed of carbon (C) / flowlin (F) is formed on the entire surface of the structure to a predetermined thickness.

At this time, the carbon rich polymer 39 has a high composition ratio of carbon (see FIG. 2B).

Then, the carbon rich polymer 39 is anisotropically etched with oxygen plasma to form the carbon rich polymer spacers 41 on the sidewalls of the photoresist pattern 37.

In this case, the contact portion of the interlayer insulating layer 35 is exposed, and the size of the carbon rich polymer spacers 41 may be arbitrarily adjusted by controlling the deposition conditions of the carbon rich polymer 39 (see FIG. 1C).

Next, the contact hole 43 is etched by using the photoresist pattern 37 and the carbon rich polymer spacer 41 as sidewall barriers in an etch selectivity ratio of the nitride film 35 and the oxide film 33 at a ratio of 1: 1. Form.

Then, the photoresist film 37 and the carbon rich polymer spacer 41 remaining in the contact hole 43 are removed by isotropic etching with oxygen plasma (see FIG. 1D).

As described above, according to the present invention, a reproducible contact hole is formed by forming a contact hole having a wine glass shape using a carbon rich polymer or forming a contact hole using only a dry etching process without a wet etching process when forming a contact hole of a fine pattern. In addition, by carrying out a series of processes in a batch, the process is simplified to reduce the cost of additional equipment has the advantage of improving the reliability of the semiconductor device.

Claims (6)

Sequentially forming a first oxide film, an interlayer insulating film, and a second oxide film on the semiconductor substrate; Forming a contact photoresist pattern on the second oxide film; Dry etching the photoresist pattern with a mask to form a second oxide film inclined, but forming a second oxide film pattern exposing a contact portion surface of the interlayer insulating film; Forming a carbon rich polymer on the entire surface of the structure; Anisotropically etching the carbon rich polymer with oxygen plasma to form a carbon rich polymer spacer on the sidewalls of the second oxide film pattern; And forming a contact hole by using the photoresist pattern and the carbon rich spacer as an etch barrier until the semiconductor substrate is exposed. 2. The method of claim 1, wherein the interlayer insulating film is formed of a nitride film or an oxide film containing a large amount of nitrogen. The method of claim 1, wherein an etching selectivity of the interlayer insulating layer and the first oxide layer is simultaneously removed at a ratio of 1: 1. Sequentially forming an oxide film and an interlayer insulating film on the semiconductor substrate; Forming a contact photoresist pattern on the interlayer insulating film; Forming a carbon rich polymer on the entire surface of the structure; Anisotropically etching the carbon rich polymer to form a carbon rich polymer spacer on sidewalls of the photoresist pattern; And forming a contact hole by using the photoresist pattern and the carbon rich spacer as an etch barrier until the semiconductor substrate is exposed. 5. The method of claim 4, wherein the interlayer insulating film is formed of a nitride film or an oxide film containing a large amount of nitrogen. The method of claim 4, wherein an etching selectivity of the interlayer insulating layer and the first oxide layer is simultaneously removed at a ratio of 1: 1.