KR100356786B1 - Method for manufacturing capacitor of semiconductor device - Google Patents

Abstract

PURPOSE: A method for manufacturing a capacitor of a semiconductor device is provided to be capable of securing the storage capacity of the capacitor by shaping an electric charge storage node of the capacitor into a saw-type multilayer. CONSTITUTION: After sequentially forming an insulating layer(2) having a contact hole and the first polysilicon layer on a semiconductor substrate(1), the first oxide layer and the first demi-spherical polysilicon are sequentially formed on the resultant structure. After forming a saw-type structure on the upper portion of the first polysilicon layer, the second oxide layer(6) is filled into the saw-type structure. After sequentially forming the second polysilicon layer, the third oxide layer, the second demi-spherical polysilicon on the resultant structure, a saw-type structure is formed on the upper portion of the second polysilicon layer.

Description

Capacitor Manufacturing Method of Semiconductor Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a capacitor of a semiconductor device, and more particularly, to form a multilayer sawtooth charge storage electrode of a capacitor during a manufacturing process of a semiconductor DLAN (hereinafter referred to as DRAM) device to secure a storage capacity of a capacitor. The present invention relates to a method for manufacturing a capacitor of a semiconductor device.

Capacitors, one of the most important elements in an integrated circuit, are particularly important when included in a circuit of a memory element in which charge is accumulated for each piece of information. In such a memory device, a random access memory (RAM), memory cells are organized in the form of a matrix, and are called along rows and columns to store or reproduce data. In particular, a dense memory element has one capacitor and one transistor, where the transistor acts as a switch to transfer or call the capacitor. In this case, when the MOS capacitor is used, since the charge is discharged within a predetermined time, it is necessary to periodically recharge the information. This type of memory device is called dynamic RAM or DRAM. DRAM requires additional circuitry for refreshing, but the memory cell area is small enough to hold more than a million memory cells on a single chip, and its low power consumption makes it very popular in today's highly integrated circuits. Element. However, as the degree of integration of semiconductor devices increases dramatically, the MOS capacitors that store information in DRAMs also reduce the storage electrode area, thereby reducing the capacity of charges accumulated in the electrodes. As a result, the memory contents are incorrectly output or the memory contents are destroyed by radiation such as α rays. In order to solve this problem, a cylindrical or fin type electrode has been proposed.

However, as described above, efforts to expand the area of the capacitor's charge storage electrode have been continually attempted, but the limitation of increasing the area of the charge storage electrode in current large-capacity semiconductor DRAM devices having a capacity of 256M DRAM or higher. In the method of using the high dielectric constant film, which is another method for increasing the capacity, it is necessary to develop an alternative material having a higher permittivity than the nitride film used as the current dielectric film, and another method for increasing the capacity. The thickness of the phosphorus dielectric film also reached the effective system thickness, and there was a difficulty in securing a process margin.

Accordingly, the present invention has been made to solve the above-mentioned problems, and the semiconductor device can meet the high integration and large capacity by increasing the surface area of the electrode by manufacturing the charge storage electrode by saw tooth formation during the capacitor formation process of the semiconductor device. An object of the present invention is to provide a capacitor manufacturing method.

In order to achieve the above object of the present invention, a capacitor manufacturing method of a semiconductor device of the present invention comprises the steps of sequentially forming an insulating film and a first polysilicon having a contact hole exposing a portion of the substrate on the semiconductor substrate; Sequentially forming a first oxide film and a first hemispherical polysilicon on the first polysilicon; Etching the first hemispherical polysilicon as a mask and a portion of the first oxide film and the first polysilicon in a sawtooth shape; Forming a second oxide film over the entire structure; Etching back the first hemispherical polysilicon, the second oxide film and the remaining first oxide film until the uppermost portion of the first polysilicon is exposed; A second polysilicon, a third oxide film and a second hemispherical polysilicon are sequentially formed on the exposed first polysilicon and the remaining second oxide film. The second hemispherical polysilicon is used as a mask, and the third oxide film and the second oxide film are formed. Etching a portion of the polysilicon into a sawtooth shape; Removing the remaining third oxide film; Etching the remaining sawtooth shaped first and second polysilicon into a predetermined form; And wet etching the second oxide film remaining between the first polysilicon and the second polysilicon to form a charge storage electrode of a capacitor having a double tooth shape.

Hereinafter, a method of manufacturing a capacitor of a semiconductor device according to the present invention as described above will be described in more detail with reference to the accompanying drawings.

The attached first to (a) to (e) is a cross-sectional view of the main portion sequentially showing a method of manufacturing a capacitor of the semiconductor device according to the present invention, first, as shown in Figure 1 (a), on the semiconductor substrate (1) Next, an insulating film 2 having a predetermined thickness is formed, and then a contact hole is formed in an area to be formed of the charge storage electrode by an etching process. Then, the first doped polysilicon 3 for the charge storage electrode was deposited in the LPCVD furnace using SiH ₄ and PH ₃ gas on the bottom and side of the contact hole and the entire surface of the insulating film 2, and then on the top thereof. After forming the first oxide film 4 to a predetermined thickness, a hemispherical polysilicon (5: Hemi Spherical Grain polysilicon) is formed on the first oxide film. The hemispherical polysilicon 5 is formed by depositing amorphous or crystalline silicon in a transition temperature section, and is formed in the shape of a hemisphere as the name.

Subsequently, as shown in FIG. 1B, the hemispherical polysilicon 5 is deposited to dry-etch the lower oxide film and the first doped polysilicon 3 to a predetermined depth to form a sawtoothed first shape. The toothed layer 11 is formed. At this time, the hemispherical polysilicon 5 is removed simultaneously with the etching of the lower layer. Thereafter, a second oxide film 6 having a high wet etch rate is formed on the entire surface of the etching resultant to a predetermined thickness such that the lower tooth layer is buried.

Then, as shown in FIG. 1 (C), the first oxide film 4 in which the wet etching rate is high and the first oxide film 4 in which the etching proceeds in a sawtooth manner is replaced with the first doped polysilicon 3. After etching back to the etch interface, the second doped silicon 7 is deposited to a predetermined thickness on the first doped polysilicon 3 exposed by the etch back and the oxide film 6 having a high wet etching rate. . Then, a third oxide film 8 and a hemispherical polysilicon 5 are sequentially formed on the second doped polysilicon 7.

Thereafter, as shown in FIG. 1D, the third oxide film 8 and the second doped polysilicon 7 are formed in the form of the hemispherical polysilicon 5 in the same manner as in FIG. The second tooth layer 12 is formed by etching to a predetermined depth of), and then a predetermined portion is dry-etched and removed to form a charge storage electrode of the capacitor.

Then, as shown in FIG. 1 (E), the second oxide film 6 having a high wet etching rate remaining between the first tooth layer 11 and the second tooth layer 12 by wet etching the specimen. ) Is completed to complete the charge storage electrode of the capacitor according to the present invention.

As described in detail above, the present invention provides a capacitor manufacturing method for a high-density, large-capacity semiconductor element, in which the charge storage electrode of the capacitor element constitutes a sawtooth shape of two layers in order to realize an increase in capacity. It is possible to increase the surface area of the charge electrode in a relatively simple process by forming a sawtooth shape using a hemispherical polysilicon rather than using a conventional photolithography process to implement the sawtooth shape. have.

1 (a) to (e) are cross-sectional views of main parts sequentially showing a method of manufacturing a capacitor of a semiconductor device according to the present invention.

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

1 semiconductor substrate 2 insulating film

3: first doped silicon 4: first oxide film

5: hemispherical polysilicon 6: second oxide film

7: second doped silicon 8: third oxide film

11: first tooth layer 12: second tooth layer

Claims (1)

Sequentially forming an insulating film having a contact hole exposing a portion of the substrate and a first polysilicon on a semiconductor substrate; Sequentially forming a first oxide film and a first hemispherical polysilicon on the first polysilicon; Etching the first hemispherical polysilicon as a mask and a portion of the first oxide film and the first polysilicon in a sawtooth shape; Forming a second oxide film on the entire structure; Etching the first hemispherical polysilicon, the second oxide film and the remaining first oxide film until the uppermost portion of the first polysilicon is exposed; Sequentially forming a second polysilicon, a third oxide film, and a second hemispherical polysilicon on the exposed first polysilicon and the remaining second oxide film; Etching the second hemispherical polysilicon as a mask and a portion of the third oxide film and the second polysilicon into a sawtooth shape; Removing the remaining third oxide film; Etching the remaining sawtooth shaped first polysilicon and the second polysilicon into a predetermined shape; And And wet-etching the second oxide film remaining between the first polysilicon and the second polysilicon to form a charge storage electrode of a capacitor having a double sawtooth shape.