KR100384791B1 - Method for manufacturing capacitor semiconductor memory device - Google Patents

Abstract

PURPOSE: A method for manufacturing a capacitor of a semiconductor memory device is provided to enhance the capacitance by using a capacitor electrode with a double cylindrical structure. CONSTITUTION: An interlayer dielectric(21), a nitride layer(22) and the first oxide layer are formed on a substrate(20). A contact hole is formed by selectively etching the first oxide layer, the nitride layer and the interlayer dielectric. An insulating spacer(25) is formed at inner walls of the contact hole. By removing the first oxide layer, the insulating spacer is protruded. The first polysilicon layer and the second oxide layer are formed on the resultant structure. A capacitor electrode pattern is formed by selectively etching the second oxide layer and the first polysilicon layer. A polysilicon spacer is formed at both sidewalls of the capacitor electrode pattern, thereby forming the first capacitor electrode(31) with a protrudent part. A dielectric film(32) and the second capacitor electrode(31-1) are formed.

Description

Capacitor Manufacturing Method of Semiconductor Memory Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a capacitor of a semiconductor memory device, and more particularly, to a method of manufacturing a capacitor of a semiconductor memory device suitable for increasing capacitance of a cylinder type capacitor.

1 is a cross-sectional view showing an embodiment of a capacitor manufacturing method of a conventional semiconductor memory device. Hereinafter, a capacitor manufacturing method of a conventional semiconductor memory device will be described with reference to the accompanying drawings.

In the conventional capacitor manufacturing method of a semiconductor device, as shown in FIG. 1A, first, the nitride film 12 is formed on the interlayer insulating film 11 laminated on the semiconductor substrate 10, and then the capacitor contact portion (A portion). The interlayer insulating film and the nitride film are photo-etched to form a contact hole 13.

Subsequently, as shown in FIG. 1B, a polysilicon layer is formed on the nitride film 12 and the contact window, and an oxide film is formed on the polysilicon layer. Then, the oxide film and the polycrystalline silicon layer are reactive ion etched by photolithography. Thus, a lower portion of the polysilicon layer 14 is formed in contact with the capacitor contact portion (site A) through the contact window, and a capacitor electrode pattern (pillar oxide) 15 is formed on the upper portion (capacitor node pattern) ( 16).

Then, as shown in FIG. 1C, the polysilicon sidewall 17 is formed on the sidewall of the capacitor electrode pattern 16. As shown in FIG.

In other words, after the polysilicon layer is formed on the capacitor electrode pattern and the nitride film, the polysilicon layer is anisotropically etched to form the polysilicon sidewalls on the sidewalls of the capacitor electrode pattern.

Subsequently, as shown in FIG. 1D, the pillar oxide film on the upper portion of the capacitor electrode pattern is removed by the wet etching method between the polysilicon side walls 17 to form the cylindrical first capacitor electrode 18.

Then, the dielectric film 19 and the second capacitor electrode 18-1 are formed on the first capacitor electrode 18 as shown in FIG.

That is, in the conventional capacitor manufacturing method of the semiconductor memory device, the first capacitor electrode is formed in a cylindrical shape, so that the capacitance increases due to the increase in the area.

However, in the conventional method of manufacturing a capacitor of a semiconductor memory device, the height of the cylindrical capacitor electrode is increased to increase the capacitance of the capacitor, thereby increasing the surface area of the capacitor electrode on which the dielectric is formed. Since the flattening of the was reduced, the problem of limiting the capacitance occurred.

The present invention has been made to solve such a problem, and an object thereof is to provide a method of manufacturing a capacitor having an increased capacitance.

In the method of manufacturing a capacitor of a semiconductor memory device according to the present invention, after forming a nitride film on an interlayer insulating film stacked on a semiconductor substrate, forming a first oxide film on the nitride film, and selectively etching the first oxide film, the nitride film, and the interlayer insulating film. Forming a contact window, forming an insulating material side wall on the sidewall of the contact window, removing the first oxide film so that the insulating material side wall protrudes, a nitride film, an insulating material side wall, and a contact window. Forming a first polycrystalline silicon layer, forming a second oxide film on the polycrystalline silicon layer, selectively etching the second oxide film and the polycrystalline silicon layer to form a capacitor electrode pattern, and forming polycrystalline silicon on the sidewalls of the capacitor electrode pattern Forming the sidewalls, removing the pillar oxide film between the polysilicon sidewalls, and forming a cylindrical shape by the polysilicon sidewalls. As formed, it comprises the steps and, the step of the dielectric film is formed on the first capacitor electrode and forming a second capacitor electrode on the dielectric film to form a first capacitor electrode with a projection formed on the insulating upper protruding material wall.

2 is a cross-sectional view showing an embodiment of a method of manufacturing a capacitor of a semiconductor memory device according to the present invention. Hereinafter, a method of manufacturing a capacitor of the semiconductor memory device according to the present invention will be described with reference to the accompanying drawings.

In one embodiment of the method for manufacturing a capacitor of a semiconductor memory device according to the present invention, first, the nitride film 22 and the first oxide film on the interlayer insulating film 21 laminated on the semiconductor substrate 20 as shown in FIG. (23) are formed by stacking them in turn, and the interlayer insulating film, the nitride film and the first oxide film are selectively etched by photolithography to form the contact window 14 at the capacitor contact portion (A 'portion).

Subsequently, as shown in FIG. 2B, after the nitride film side wall 25 is formed on the inner wall of the contact window 24, the first oxide film is removed so that the upper portion of the nitride film side wall protrudes.

At this time, the nitride film side wall is formed by forming an nitride film on the first oxide film and the contact window, and then the nitride film is formed by anisotropic dry etching, and the upper height of the protruding nitride film side wall is controlled by the thickness of the first oxide film or by the degree of anisotropic etching of the nitride film. do.

As shown in FIG. 2C, the nitride film 22, the nitride film side wall 25 protruded from the top, and the polysilicon layer 26 are formed on the contact window, and the second oxide film 27 is formed on the polysilicon layer. To form.

Subsequently, as shown in FIG. 2D, the second oxide film and the polysilicon layer are reactively ion-etched by photolithography, and a polysilicon layer 26 ′ which contacts the capacitor contact portion through a contact window is provided in the lower portion thereof. And a capacitor electrode pattern 29 having a pillar oxide layer 28 formed thereon.

As shown in FIG. 2E, the polysilicon side walls 30 are formed on the sidewalls of the capacitor electrode patterns 29. As shown in FIG.

Subsequently, as shown in FIG. 2B, the pillar oxide film on the upper portion of the capacitor electrode pattern is wet-etched between the polysilicon sidewalls 30 to be cylindrically formed by the polysilicon sidewalls, and the upper side protrudes on the nitride film sidewall 25. The first capacitor electrode 31 having the protrusion B portion is formed.

As shown in FIG. 2, the dielectric film 32 is formed on the first capacitor electrode 31, and the second capacitor electrode 31-1 is formed on the dielectric film.

In the method for manufacturing a capacitor of a semiconductor memory device according to the present invention, the capacitor electrode is formed in a double cylindrical shape, thereby increasing the surface area of the capacitor electrode, thereby increasing the capacitance of the capacitor.

1 is a cross-sectional view showing an embodiment of a method of manufacturing a capacitor of a conventional semiconductor memory device.

2 is a cross-sectional view showing an embodiment of a capacitor manufacturing method of a semiconductor memory device according to the present invention.

※ Explanation of code about main part of drawing ※

10.20. Semiconductor Substrate 11.21. Interlayer insulation film

12,22. Nitride Film 13.24. Contact window

14.26.26 '. Polycrystalline Silicon Layer 15.28. Pillar oxide

16,29. Capacitor electrode pattern 17,30. Polycrystalline silicon side wall

18.31. First Capacitor Electrode 18-1.31-1. Second capacitor electrode

19.32. Dielectric Film 23. First Oxide Film

25. Nitride side wall 27. Second oxide layer

A.A '; Capacitor contact point B; projection part

Claims (4)

In the method of manufacturing a capacitor of a semiconductor memory device, Forming a nitride film on the interlayer insulating film stacked on the semiconductor substrate, and then forming a first oxide film on the nitride film; Selectively etching the first oxide film, the nitride film, and the interlayer insulating film to form a contact window; Forming an insulating material side wall on the sidewall of the contact window; Removing the first oxide film so that an upper portion of the side wall of the insulating material protrudes; Forming a first polycrystalline silicon layer on the nitride film, the insulating material side wall, and the contact window, and then forming a second oxide film on the polycrystalline silicon layer; Selectively etching the second oxide film and the polysilicon layer to form a capacitor electrode pattern formed of a polycrystalline silicon layer at a lower portion thereof and a pillar oxide layer at an upper portion thereof; Forming a polysilicon sidewall on a sidewall of the capacitor electrode pattern; Removing the pillar oxide film between the polysilicon side walls to form a first capacitor electrode having a protrusion formed on the insulating material side wall while being formed in a cylindrical shape by the polysilicon side wall; And forming a dielectric film on the first capacitor electrode, and then forming a second capacitor electrode on the dielectric film. 2. The method of claim 1, wherein the height of the side wall of the insulating material protruding is adjusted by the thickness of the first oxide film. The method of claim 1, wherein the protruding height of the side wall of the insulating material is controlled by the degree of etching while forming the insulating material film by anisotropic etching after forming the insulating material film on the contact window of the first oxide film. Method for manufacturing capacity of semiconductor memory device. The side wall of the insulating material is formed on the first oxide film and the contact window, and the nitride film is anisotropically etched to form a nitride film side wall on the sidewall of the contact. A method for manufacturing a capacitor of a semiconductor memory device, characterized in that.