KR19990025132A - Contact Forming Method of Semiconductor Device - Google Patents

Abstract

The present invention relates to a method for forming a contact of a semiconductor device which is formed for connection between a device and a device.

According to an embodiment of the present invention, a first insulating layer is formed on an entire surface of an upper surface of a semiconductor substrate on which a plurality of gate electrodes are formed through a gate oxide layer. Forming a spacer between the plurality of gate electrodes, forming a second insulating film on the first insulating film, and performing an etch back process to form a spacer on the first insulating film on the sidewall of the first contact hole. Forming a second contact hole having a, and forming a metal film by depositing a metal material inside the second contact hole.

Therefore, by forming the first contact hole larger than the diameter of the desired contact hole, the range of alignment limit of the exposure apparatus can be improved, and the step coverage can be improved by forming the spacer on the sidewall of the gate electrode.

Description

Contact Forming Method of Semiconductor Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a contact in a semiconductor device, and more particularly, to a method for forming a contact in a semiconductor device formed for connection between a device and a device.

In the semiconductor device manufacturing process, contacts are formed in the gate electrode, the source region, and the drain region, for example, to connect the devices and the pads, or the like.

In addition, as semiconductor devices are highly integrated and miniaturized, a contact is formed to connect a lower electrode and an upper electrode on the multilayer structure as a multilayer structure in which unit cells are stacked is selected.

A method of forming a contact of a conventional semiconductor device will be described with reference to FIG. 1. First, a gate electrode 14 is formed of a conductive material such as polysilicon on a semiconductor substrate 10 through a gate oxide film 12. An impurity region 16 is formed in the semiconductor substrate 10 by performing an ion implantation process using a self-aligning method using the gate electrode 14 as a mask. Further, after the first insulating film 18 such as an oxide film and the second insulating film 20 such as a BPSG film (Borophosphorsilicate glass layer) are sequentially formed on the semiconductor substrate 10 on which the impurity region 16 is formed, the reticle ( The contact hole 22 is formed by performing a conventional photolithography process using a mask such as Reticle). The metal layer 24 is formed by depositing a metal material such as aluminum (Al) into the contact hole 22 using a physical deposition process such as sputtering.

By the way, when forming a contact through the first insulating film and the second insulating film by performing a normal photolithography process, the semiconductor device has recently been highly integrated and the size of the contact hole has become smaller. As the limit also became smaller, there was a difficulty in the progress of the exposure process.

In addition, in recent years, as semiconductor devices have been highly integrated, the size of the contact hole becomes smaller, resulting in poor step coverage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a contact of a semiconductor device, which can increase the limit of the alignment range of a construction equipment when forming a contact hole by performing a conventional photolithography process.

Another object of the present invention is to provide a method for forming a contact of a semiconductor device capable of improving step coverage.

1 is a cross-sectional view for explaining a contact forming method of a conventional semiconductor device.

2 to 5 are cross-sectional views illustrating an embodiment of a method for forming a contact in a semiconductor device according to the present invention.

※ Explanation of symbols for main parts of drawing

10, 30: semiconductor substrate 12, 32: gate oxide film

14, 34: gate electrode 16, 36: impurity region

18, 38: 1st insulating film 20, 40: 2nd insulating film

22: contact hole 24, 50: metal film

42: first contact hole 44: third insulating film

46 spacer 48 second contact hole

According to another aspect of the present invention, there is provided a method of forming a contact for a semiconductor device, comprising: (1) forming a first insulating film on an upper surface of a semiconductor substrate on which a plurality of gate electrodes are formed through a gate oxide film; Performing a conventional photolithography process on a first insulating film to form a first contact hole larger than a desired diameter between the plurality of gate electrodes, (3) forming a second insulating film on the first insulating film, ( 4) forming a second contact hole having a desired diameter by forming a spacer on the first insulating film on the sidewall of the first contact hole by performing an etch back process, and (5) forming a metal material inside the second contact hole. And evaporating to form a metal film.

The first insulating layer may be formed of a double insulating layer including a lower first oxide layer and an upper BPSG layer.

In addition, the second insulating film is characterized in that the oxide film.

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

First, referring to FIG. 2, after the gate electrode 34 is formed of a conductive material such as polysilicon on the semiconductor substrate 30 via the gate oxide film 32, the gate electrode 14 is masked. The impurity region 36 is formed in the semiconductor substrate 30 by performing an ion implantation process using a self-aligning method used as a? Further, a first insulating film 38 such as an oxide film and a second insulating film 40 such as a BPSG film (Borophosphorsilicate glass layer) are sequentially formed on the semiconductor substrate 30 on which the impurity region 36 is formed, and then a reticle or the like is formed. A conventional photolithography process using a mask of is performed to form a first contact hole 42 larger than a desired diameter. Since the diameter of the first contact hole 42 is larger than that of the related art, the range of alignment limit of the exposure apparatus is increased.

Next, as shown in FIG. 3, a third insulating film 44 such as an oxide film is formed on the semiconductor substrate 30 on which the first contact hole 42 is formed.

Next, as shown in FIG. 4, a second contact hole 48 having a desired diameter is formed by forming a spacer 46 by performing an etch back process such as reactive ion etching. do. The step coverage of the second insulating film 40 is improved by forming the spacers 46.

Finally, as shown in FIG. 5, a metal film 50 is formed by depositing a metal material such as aluminum into the second contact hole 48 using a physical deposition process such as sputtering to form a contact.

Therefore, according to the present invention, by forming the first contact hole larger than the diameter of the desired contact hole, the range of the alignment limit of the exposure apparatus can be improved.

In addition, by forming a spacer on the sidewall of the gate electrode, the step coverage of the second insulating layer can be improved.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (4)

(1) forming a first insulating film on the entire upper surface of the semiconductor substrate on which the plurality of gate electrodes are formed through the gate oxide film; (2) performing a normal photolithography process on the first insulating film to form a first contact hole larger than a desired diameter between the plurality of gate electrodes; (3) forming a second insulating film on the first insulating film; (4) forming a second contact hole having a desired diameter by performing a etch back process to form a spacer on the first insulating film of the sidewall of the first contact hole; (5) forming a metal film by depositing a metal material in the second contact hole; And a contact forming method of a semiconductor device. The method of claim 1, And the first insulating film is formed of a double insulating film. The method of claim 2, And the double insulating layer is formed of a lower first oxide film and an upper BPSG film. The method of claim 1, And the second insulating film is formed of an oxide film.