KR19980045328A - Semiconductor device manufacturing method - Google Patents

Abstract

The present invention discloses a method for manufacturing a semiconductor device. A method of manufacturing a semiconductor device according to the present invention includes providing a semiconductor substrate having a gate oxide film and a polysilicon layer laminated thereon; Doping certain impurities to impart conductivity to the polysilicon layer; Rinsing the polysilicon surface with a chemical solution to remove the impurities; Forming a photoresist pattern on the polysilicon layer; Removing residues of the impurities and impurities generated in the photoresist pattern forming process; Etching the polysilicon layer in the form of a photoresist pattern; Removing the photoresist pattern; And cleaning the gate electrode pattern with a predetermined chemical solution.

Description

Manufacturing method of semiconductor device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of manufacturing a semiconductor device in which a polysilicon layer is etched to form a gate electrode pattern without defects.

A method of forming a gate electrode pattern according to the prior art will now be described with reference to FIGS. 1A and 1B.

Referring to FIG. 1A, after the gate oxide film 2 and the polysilicon layer 3 are sequentially formed on the semiconductor substrate 1, dopants are doped to impart conductivity to the polysilicon layer 3. Subsequently, a photosensitive film is coated on the doped polysilicon layer 3, and a photosensitive film pattern 4 is formed by performing an exposure and development process so that a part of the polysilicon 3 is exposed.

Referring to FIG. 1B, in order to remove a natural oxide film (not shown) formed on the polysilicon layer 3, an etching process is performed for about 10 seconds using SF ₆ and He gas as plasma, and then an exposed polysilicon layer ( 3) is etched with He and Cl ₂ gas to form a gate electrode pattern 3 '. Then, the photosensitive film pattern 4 is removed.

However, in the conventional technique as described above, since the natural oxide film or particles generated when the polysilicon layer is doped with impurities are not completely removed during the etching process by SF ₆ and He gas, the gate bridge after the polysilicon layer is etched. (bridge: 5) causes a defect such as lowering the electrical characteristics and manufacturing yield of the device.

Therefore, the present invention removes the particles and oxide film components formed on the polysilicon layer by using CF ₄ gas which has little effect on the polysilicon layer instead of SF ₆ and He gas and is excellent in removing polymer particles. An object of the present invention is to provide a method of manufacturing a semiconductor device capable of forming a gate electrode pattern in which a defect does not occur by etching a polysilicon layer using Cl ₂ gas.

1A and 1B are cross-sectional views illustrating a method of manufacturing a semiconductor device according to the prior art.

2A to 2D are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with the present invention.

* Description of the symbols for the main parts of the drawings *

11: semiconductor substrate 12: gate oxide film

13: polysilicon layer 13 ': gate electrode pattern

14: P ₂ O ₅ oxide film 15: photosensitive film pattern

16: photosensitive particle

The above object is to provide a semiconductor substrate in which a gate oxide film and a polysilicon layer are stacked; Doping certain impurities to impart conductivity to the polysilicon layer; Rinsing the polysilicon surface with a chemical solution to remove the impurities; Forming a photoresist pattern on the polysilicon layer; Removing residues of the impurities and impurities generated in the photoresist pattern forming process; Etching the polysilicon layer in the form of a photoresist pattern; Removing the photoresist pattern; And cleaning the gate electrode pattern with a predetermined chemical solution.

According to the present invention, after removing particles and oxide components formed on the polysilicon layer using CF ₄ gas, the polysilicon layer is etched using Cl ₂ gas to form a gate electrode pattern in which no defect occurs. Can be.

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, a gate oxide film 12 having a thickness of about 170 kPa and a polysilicon layer having a thickness of about 2,500 to 3,500 kPa are sequentially formed on the semiconductor substrate 11, and then the polysilicon layer 13 is formed. POCl ₃ is doped to give conductivity. At this time, POCl ₃ and O ₂ gas react to form a P ₂ O ₅ oxide film 14 on the polysilicon layer 13.

Referring to FIG. 2B, the P ₂ O ₅ oxide layer 14 acts as a barrier in the subsequent etching process of the polysilicon layer 13 to cause a bridge phenomenon between the gate electrode patterns. Accordingly, the semiconductor substrate on which the P ₂ O ₅ oxide layer 14 is formed is dipped in 100: 1 BOE (Buffered Oxide Etchant) for about 3 minutes to prevent the bridge pattern between gate patterns. The P ₂ O ₅ oxide layer 14 is removed. do. Subsequently, after the photosensitive film of about 1.2 micrometers thickness is apply | coated on the polysilicon layer 13, an exposure and image development process is performed, and the photosensitive film pattern 15 is formed.

In the above process, the P ₂ O ₅ oxide film 14 is not completely removed but remains on the polysilicon layer 13 on which a rinse process using a BOE solution has been performed, and the photoresist particle 16 is formed on the photoresist pattern. Since the portion of (15) is covered, residues of the P ₂ O ₅ oxide film 14 and the photoresist particle 16 remaining in the subsequent etching process of the polysilicon layer 13 may cause a bad pattern. .

Referring to FIG. 2C, a plasma etching process using CF ₄ gas having excellent removal effect of carbon and oxide polymers on the P ₂ O ₅ oxide film 14 residue and photoresist particle 16 on the exposed polysilicon layer 13 is performed. To remove it. At this time, the plasma etching process is performed under the following conditions.

Pressure: 260mT, Power: 300watt, Time: 1 Minute

Distance between upper and lower electrodes in etching equipment: 1.0㎝

He: 150 SCCM, CF ₄ : 50 SCCM

Wherein the CF ₄ gas is oxide to poly good choice for silicon ratio than the SF _6, as compared with SF ₆ it is possible to perform the etching process for a number of sufficiently low reactivity of time for the polysilicon P ₂ O ₅ oxide film 14 The removal efficiency of the residue and the photosensitive film particle 16 can be improved.

Referring to FIG. 2D, after etching in an end of point (EOP) method using Cl ₂ gas of the polysilicon layer 13, Cl ₂ gas is used again to remove the residue of the polysilicon layer 13. To over-etch. Then, after the photoresist pattern 15 is stripped with O ₅ plasma, the etched polysilicon layer 13 is cleaned with sulfuric acid to form a gate electrode pattern 13 ′.

As described above, in the method of manufacturing a semiconductor device of the present invention, a bridge between the gate electrode patterns is formed by etching the polysilicon layer by an etching process using CF ₄ gas and an etching process by Cl ₂ gas to form a gate electrode pattern. And it is possible to prevent the pattern failure to improve the electrical characteristics and manufacturing yield of the device.

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 (10)

Providing a semiconductor substrate having a gate oxide film and a polysilicon layer laminated thereon; Doping certain impurities to impart conductivity to the polysilicon layer; Rinsing the polysilicon surface with a chemical solution to remove the impurities; Forming a photoresist pattern on the polysilicon layer; Removing residues of the impurities and impurities generated in the photoresist pattern forming process; Etching the polysilicon layer in the form of a photoresist pattern; Removing the photoresist pattern; And cleaning the gate electrode pattern with a predetermined chemical solution. The method of claim 1, wherein the impurity doped in the polysilicon layer is POCl ₃ . The method of claim 1, wherein the chemical solution for rinsing the surface of the polysilicon layer is 100: 1 BOE. The method of claim 3, wherein the rinsing step is performed for about 3 minutes. The method of claim 1, wherein impurities generated in the rinsing process and the photoresist pattern forming process are removed by a plasma etching process using CF ₄ gas. The etching condition of claim 5, wherein the etching conditions in the plasma etching process using the CF ₄ gas Pressure: 260mT, Power: 300watt, Time: 1 Minute Distance between upper and lower electrodes in etching equipment: 1.0㎝ He: 150 SCCM, CF ₄ : 50 SCCM A method for manufacturing a semiconductor device, characterized in that. The method of claim 1, wherein the etching of the polysilicon layer is performed using Cl ₂ gas. The method of claim 1, wherein the etching of the polysilicon layer is performed using an end of point (EOP) method. The method of claim 1, wherein the photoresist pattern is removed by an O ₂ plasma etching process. The method of claim 1, wherein the chemical solution used in the cleaning process of the gate electrode pattern is sulfuric acid.