KR19980038881A - Method for forming conductive film of semiconductor device - Google Patents

Abstract

The present invention relates to a method for forming a conductive film of a semiconductor device, comprising: providing a substrate having an oxide film, a conductive film, and a photosensitive film pattern formed on a semiconductor substrate, etching the conductive film to expose the oxide film; ₄ F: a step of dipping the substrate in a mixed solution of H ₂ O and, secondly NH ₄ OH: removing the photoresist pattern and the step of dipping the substrate, a mixed solution of H ₂ O: H ₂ O ₂ It is characterized by including the process of forming a predetermined conductive film pattern.

Description

A method for forming a conductive film of a semiconductor device.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a conductive film of a semiconductor device, and more particularly, to a method for forming a conductive film of a semiconductor device capable of forming a conductive film pattern without loss of an oxide film using a predetermined chemical solution.

Recently, dry etching has attracted the attention of ultra-fine as an etching method for forming an ultra-fine pattern in the manufacturing process of the ultra-high density semiconductor device. The dry etching is a method of generating a plasma using a reactive gas in a high vacuum state, and etching various films formed on a semiconductor substrate using the generated plasma ions, neutral radicals, atoms, molecules, and the like.

In general, in etching a polysilicon film or silicide film, which is a conductive film used for a gate electrode and a capacitor of a MOS transistor, Cl ₂ gas is mainly used as a main reactive gas.

A method of forming a conductive film of a semiconductor device according to the related art in which Cl ₂ is used as a reactive gas will be described with reference to FIGS. 1A to 1C.

Referring to Figure 1A. In order to form a predetermined conductive film pattern on the semiconductor substrate 1, first, a photosensitive film pattern 4 is formed on the conductive film 3 formed on the oxide film 12, and then, during the etching process HBr gas or oxygen (O ₂ ) gas is added to Cl ₂ gas, which is the main etching gas, in consideration of carbon (C) supplied from the turn 4, and the conductive film 3 is dry-etched by the reactive etching gas. . As a result, a portion of the oxide film 2 is exposed.

Referring to FIG. 1B, in order to remove the polymer (5) which is a by-product of the process, the Cl component remaining on the side of the conductive film (3) is replaced with the F component which is easy to remove with a chemical solution. The semiconductor substrate 1 having a portion of the oxide film 2 exposed is dipped in an HF solution, for example, a solution mixed with HF: H ₂ O = 1: 50 for about 10 seconds, and then cleaned with ultrapure water. And then dried.

Referring to Fig. 1C, the photosensitive film pattern 4 is removed, whereby a predetermined conductive film pattern 3 'is formed.

However, in the prior art as described above, in the process for removing the by-product polymer by replacing the Cl component remaining on the side of the conductive film with the F component, wet etching of the unwanted oxide film is accompanied, thereby maintaining a constant thickness of the oxide film. In addition, since the phenomenon that the oxide film is undercut occurs under the conductive film, there is a problem that the characteristics of the device are deteriorated.

Accordingly, an object of the present invention is to use a method of forming a conductive film of a semiconductor device capable of removing predetermined impurities remaining on the side of the conductive film without loss of an oxide film at the bottom using NH ₄ F and NH ₄ 4OH solutions instead of the HF solution. To provide.

1A to 1C are cross-sectional views for explaining a method for forming a conductive film of a semiconductor device according to the vertical technique.

2A to 2D are cross-sectional views for explaining a method of forming a conductive film of a semiconductor device according to the present invention.

* Explanation of symbols for main parts of the drawings

11 semiconductor substrate 12 oxide film

13: conductive film 14: photosensitive film pattern

15 polymer 13 'conductive film pattern

An object of the present invention as described above is to provide a substrate having an oxide film, a conductive film and a photosensitive film pattern formed on a semiconductor substrate, to expose the oxide film by etching the conductive film, and NH ₄ F: H ₂ O Dipping the substrate into a mixed solution of the solution, secondly dipping the substrate into a mixed solution of NH ₄ OH: H ₂ O ₂ : H ₂ O, and removing the photosensitive film pattern to form a predetermined conductive film pattern. It is achieved by the method for forming a conductive film of a semiconductor device, comprising the step of forming.

According to the present invention, by using a mixed solution containing a NH ₄ F solution to remove the Cl component remaining on the side of the conductive film, the polymer is a mixed solution containing a NH ₄ OH solution, so that the oxide film is not lost The conductive film pattern of can be formed.

EXAMPLE

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to FIGS. 2A to 2D.

Referring to FIG. 2A, in a state in which an oxide film 12, a conductive film 13, and a photosensitive film pattern 14 are formed on a semiconductor substrate 11, HBr or oxygen is formed in Cl ₂ gas to form a predetermined conductive film pattern. The conductive film 13 is etched in the form of the photosensitive film pattern 14 by anisotropic transient etching using the etching gas to which the (O ₂ ) gas is added. As a result, the oxide film 12 is exposed. The conductive film 13 here is a polysilicon or silicide film.

Referring to FIG. 2B, in order to replace the Cl component remaining on the side of the conductive film 13 with the F component which is easily removed by the chemical solution, NH ₄ F: H ₂ O = 1: 1: 1: 1: It is dipped in a mixed solution at room temperature having a ratio of 10 for about 10 to 60 seconds. Substituted F component is washed with ultrapure water and then dried. At this time, the oxide film 12 is not etched during the treatment by the mixed solution.

Referring to FIG. 2C, in order to remove the polymer 15 which is a by-product generated on the side of the conductive film 13, NH ₄ OH: H ₂ O ₂ : H ₂ O = 1: 1: 5 to 1: 1: 10 It is dipped in a mixed solution at room temperature having a ratio of about 5 to 10 minutes, washed with ultrapure water, and then dried. As in the Cl removal process of FIG. 2B, the oxide film 12 is not etched in the polymer removal process.

Referring to FIG. 2D, the photosensitive film pattern 14 is removed to form the predetermined conductive film pattern 13 ′. As a result, the oxide film 12 having a constant thickness can be obtained, whereby the reliability of the semiconductor element can be improved.

As described above, the conductive film forming method of the semiconductor device of the present invention, in the manufacturing process of the ultra-high density semiconductor device, by forming a predetermined ultra-fine conductive film pattern without loss of the oxide film under the conductive film, the reliability of the semiconductor device Can be improved.

Meanwhile, although specific embodiments of the present invention have been described and illustrated, modifications and variations can be made by those skilled in the art. Accordingly, the following claims are to be understood as including all modifications and variations as long as they fall within the true spirit and scope of the present invention.

Claims (8)

Providing a substrate having an oxide film, a conductive film, and a photoresist pattern formed on the semiconductor substrate, etching the conductive film to expose the oxide film, and first dipping the substrate in a mixed solution of NH ₄ F: H ₂ O. And dipping the substrate in a mixed solution of NH ₄ OH: H ₂ O ₂ : H ₂ O, and removing the photosensitive film pattern to form a predetermined conductive film pattern. A conductive film forming method of a semiconductor device. The method of forming a conductive film of a semiconductor device according to claim 1, wherein the conductive film is a polysilicon film or a silicide film. The method for forming a conductive film of a semiconductor device according to claim 1, wherein the mixed solution NH ₄ F: H ₂ O = 1: 1 to 1:10. The method of claim 1, wherein the first dipping process is performed at room temperature for about 10 to 60 seconds. The method of forming a conductive film of a semiconductor device according to claim 1, wherein the mixed solution has a ratio of NH ₄ OH: H ₂ O ₂ : H ₂ O = 1: 1: 1-5: 1: 1: 10. The method of claim 1, wherein the dipping in the second mixed solution is performed at room temperature for about 5 minutes to 10 minutes. The method of forming a conductive film of a semiconductor device according to claim 1, further comprising a step of washing and drying with ultrapure water between the first dipping step and the second dipping step. The method of forming a conductive film of a semiconductor device according to claim 1, further comprising a step of washing and drying with ultrapure water after dipping into the second mixed solution before removing the photoresist pattern.