KR930012118B1 - Method of fabricating a semicondcutor device - Google Patents

Abstract

The semiconductor device is prepared by depositing 1st conductive layer as 1st electrode of capacitor on a substrate, depositing dielectric film thereon, depositing primary 2nd conductive layer as 2nd electrode, depositing an antioxidizing film on the 2nd conductive layer, patterning 1st conductive layer, dielectric film, 1st, 2nd conductive layer and antioxidizing film all at a time by a lithography process, oxidizing them to form an oxide film at the side face of capacitor pattern, removing an antioxidizing film, depositing secondary 2nd conductive layer on the side oxide film and the primary 2nd conductive layer.

Description

Manufacturing Method of Semiconductor Device

1a to 1d is a flow chart of a capacitor manufacturing process according to the prior art.

2a to 2f is a flow chart of a capacitor manufacturing process according to the present invention.

3 is an embodiment in which the capacitor according to the present invention is applied to a stack capacitor structure.

4 is an embodiment in which the capacitor according to the present invention is applied to a stack-trench capacitor structure.

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a capacitor of a semiconductor memory device.

Recently, semiconductor memory chips, such as DRAM devices, have entered the mega era due to the advancement of the micro semiconductor manufacturing technology. Such mega era DRAM devices have been achieved by the miniaturization technology of MOS transistors. As devices become smaller due to the miniaturization technology of MOS transistors, the area of capacitors in devices is also reduced, thereby increasing the need for sufficient capacitor capacity.

Accordingly, the three-dimensional structure of the stack type capacitor cell and the trench type capacitor cell was devised to secure the capacity of the capacitor, and the stack-trench merging structure and the double stack structure were proposed as more advanced structures. It became.

A method of forming a capacitor having the above structure will be briefly described with reference to FIGS. 1A to 1D as follows.

As shown in FIG. 1A, the storage electrode 1 serving as the first electrode of the capacitor, for example, polysilicon, is deposited and then covered with a photoresist on the surface and exposed and developed through a mask to leave the photoresist pattern 2.

Here, reference numeral 10 denotes a semiconductor substrate.

Next, as shown in FIG. 1B, the photoresist pattern 2 is used as an etch mask to form a pattern by anisotropically etching the storage electrode 1, and then as shown in FIG. 1C, the dielectric film 3 is formed. For example, an ONO (Oxide / Nitride / Oxide) film is deposited.

Subsequently, as shown in FIG. 1d, a plate electrode 4, for example, polycrystalline silicon, which becomes the second electrode of the capacitor, is formed on the dielectric film 3, thereby completing the capacitor.

When the capacitor is formed in this manner, as described above, after the capacitor first electrode serving as the storage electrode is formed, the dielectric film and the capacitor second electrode serving as the plate electrode are formed. In this case, the capacitor first electrode is patterned. In the photolitho-graphy process, the photoresist is not completely removed, which may cause damage when the capacitor first electrode is contaminated or etched.

In addition, deterioration of the dielectric film at the corners of the capacitor electrode caused by forming the dielectric film after patterning the capacitor first electrode is also a problem.

Such problems are further exacerbated in the shape of the storage electrode in the case of a trench type or a stack-to-trench type capacitor.

An object of the present invention is to provide a method of manufacturing a capacitor that can improve the reliability of the capacitor in order to solve the above problems.

The present invention for achieving the above object is a process of depositing a first conductive layer that is a capacitor first electrode on a semiconductor plate, and a process of depositing a dielectric film on the first conductive layer, and a capacitor second electrode on the dielectric film Depositing a primary second conductive layer, depositing an oxidation blocking film on the primary second conductive layer, photographing the first conductive layer, the dielectric film, the primary second conductive layer, and the antioxidant film. Patterning the capacitor pattern at a time by a lithographic process; oxidizing the patterned first conductive layer, the dielectric film, the primary second conductive layer, and the anti-oxidation film to form an oxide film on the side portion of the capacitor pattern; And removing the antioxidant film, and forming a secondary second conductive layer on the side oxide film and the primary second conductive layer.

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

As shown in FIG. 2A, the first conductive layer 11 serving as the capacitor first electrode, for example, polycrystalline silicon or single crystal silicon, is deposited on the semiconductor substrate. Here, reference numeral 21 denotes a semiconductor substrate.

Subsequently, as shown in FIG. 2B, a dielectric film 12, such as an oxide film or an oxide film or an ONO (Oxide / Nitride / Oxide) film, is grown on the first conductive layer by 30 to 300 microseconds. After the second conductive layer 13, such as polycrystalline silicon, is grown to a thickness of about 500 to 5000 A by LPCVD (Low Pressure Chemical Vapor Deposition) method, an antioxidant film 14, for example, a nitride film is placed on the surface of about 100 to 3000 Pa. To grow.

Next, as shown in FIG. 2C, the first conductive layer 11, the dielectric film 12, and the first second conductive layer are temporarily made by using an unillustrated mask for patterning the first conductive layer 11. (13) and the antioxidant film 14 are patterned by dry etching.

Subsequently, as shown in FIG. 2D, the oxide film 15 is grown on the side of the oxide pattern thermally oxidized in a furnace by about 100 to 2000 microseconds. At this time, since the anti-oxidation film 14 is covered on the second conductive layer 13, only the side surface of the pattern is oxidized.

Next, as shown in FIG. 2E, the antioxidant layer 14 is removed by wet etching or dry etching.

Subsequently, as illustrated in FIG. 2F, the secondary second conductive layer 16, for example, polysilicon is deposited on the primary second conductive layer 13 exposed after removing the antioxidant layer 14. To complete the capacitor.

3 and 4 illustrate examples of applying the capacitor according to the present invention to a stack capacitor structure and a stack-transistor capacitor structure, respectively.

In FIG. 3 in which the present invention is applied to a stack capacitor structure, a field oxide film 22 is grown on a semiconductor substrate 21 to define an active region, and then a gate electrode of a transistor, which is a component of a memory cell, is formed on the active region. 23, the source region 24 and the drain region 25 are formed, and the gate electrode 26 is formed in a predetermined portion of the field oxide film 22. After the insulating layer 27 is formed on the entire surface of the structure, an opening is formed on the insulating layer above the source region by a photolithography process, and then, the first conductive layer 28 and the dielectric are applied to the present invention. The film 29, the primary -P2 conductive layer 3, the side oxide film 31 and the secondary second conductive layer 32 are formed in this order.

In FIG. 4 in which the present invention is applied to the stack-trencher capacitor structure, the process up to forming the opening on the source region is the same as the manufacturing process of the stack capacitor shown in FIG. The same reference numerals denote the same reference numerals, and a description thereof will be omitted. After forming the opening, a trench is formed using the formed insulating layer 27, and then the present invention is applied as described in FIG. The first conductive layer 28, the dielectric film 29, the primary second conductive layer 3, the side oxide film 31, and the secondary second conductive layer 32 are sequentially formed.

As described above, according to the method of manufacturing a capacitor, the first conductive layer serving as the capacitor first electrode, the dielectric film, and the second conductive layer serving as the capacitor second electrode are sequentially formed and then patterned. Therefore, in the conventional method, the problem of contamination by the photoresist of the first conductive layer or the risk of damage due to etching caused by first patterning the first conductive layer and then forming the dielectric film and the second conductive layer is eliminated.

In addition, since the first conductive layer and the dielectric film are simultaneously patterned, when the dielectric film is formed after the conventional first conductive layer patterning, the contamination of the first conductive layer and the degradation of the dielectric film occurring at the corners are prevented, thereby eliminating the risk of leakage. Capacitors with excellent characteristics and high reliability are realized.

Claims (10)

Depositing a first conductive layer serving as a capacitor first electrode on a semiconductor substrate, depositing a dielectric film onto the first conductive layer, and depositing a primary second conductive layer serving as a capacitor second electrode on the dielectric film. And depositing an anti-oxidation film on the primary second conductive layer, and patterning the first conductive layer, the dielectric film, the primary second conductive layer and the anti-oxidation film into a capacitor pattern all at once by a photolithography process. And oxidizing the patterned first conductive layer, the dielectric film, the primary second conductive layer, and the antioxidant film to form an oxide film on a side portion of the capacitor pattern, removing the antioxidant film, and the side oxide film; And depositing a secondary second conductive layer on the primary second conductive layer. The method of claim 1, wherein the first conductive layer is polycrystalline silicon or single crystal silicon. The method of manufacturing a semiconductor device according to claim 1, wherein said dielectric film is an oxide film or an ONO (Oxide / Nitride / Oxide) film having a thickness of 30 to 300 Å. The method of manufacturing a semiconductor device according to claim 1, wherein the primary second conductive layer is made of polycrystalline silicon having a thickness of 500 to 5000 GPa grown by LPCVD. The method of manufacturing a semiconductor device according to claim 1, wherein the anti-oxidation film is a nitride film having a thickness of 100 to 3000 GPa. The method of manufacturing a semiconductor device according to claim 1, wherein the side oxide film is grown to 100 to 2000 GPa using a furnace. The method of manufacturing a semiconductor device according to claim 1, wherein the step of removing the antioxidant film is by wet etching or dry etching. The method of manufacturing a semiconductor device according to claim 1, wherein the secondary second conductive layer is polycrystalline silicon having a thickness of 100 to 3000 GPa. The method of manufacturing a semiconductor device according to claim 1, wherein the method of manufacturing the semiconductor device is used for a stack capacitor. The method of manufacturing a semiconductor device according to claim 1, wherein the method of manufacturing the semiconductor device is used by a stack trench capacitor.