KR20060124900A - Manufacturing method of semiconductor device - Google Patents

Abstract

The present invention can prevent the uniformity of the process during the subsequent etching process (patterning process) due to the step between the field region and the active region during the gate electrode forming process of the semiconductor device using the STAR (STep gated Asymmetric Recess) process The present invention provides a method of manufacturing a semiconductor device in which the pad nitride film is formed on a substrate defined as a field region and an active region, and the trench is formed by etching the pad nitride layer and the substrate in the field region. Forming an isolation layer, forming an isolation layer to fill the trench, forming an etching mask to expose a portion of the pad nitride layer in the active region, and performing an etching process using the etching mask. Etching the pad nitride layer and removing the etch mask, and then etching the pad nitride layer. Recessing the exposed substrate to a predetermined depth by performing an etching process using a pad nitride film as a hard mask, and removing the pad nitride film to form a protrusion in the center of the substrate It provides a method of manufacturing.

Description

Manufacturing method of semiconductor device {METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE}

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

Figure 2 is a cross-sectional view of a semiconductor device manufactured by a method for manufacturing a semiconductor device according to the prior art.

3A to 3D are cross-sectional views of a method of manufacturing a semiconductor device in accordance with a preferred embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

10, 110: substrate

11, 111: pad oxide film

12, 112: pad nitride film

14: trench

15, 113: device isolation film

17, 114: lower antireflection film

18, 115: Photosensitive film pattern (STAR mask)

19, 119: projection

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for forming a gate electrode of a semiconductor device using a star gated asymetric recess (STAR) process in a DRAM device manufacturing process.

The semiconductor device includes a plurality of unit devices therein. As the semiconductor devices are highly integrated, devices must be formed at a high density on a constant cell area, thereby gradually decreasing the size of unit devices such as transistors and capacitors. In particular, as the design rule decreases in the semiconductor memory devices such as DRAM, the size of the semiconductor devices formed inside the cell is gradually decreasing. In fact, in recent years, the minimum line width of a DRAM device is formed to be 0.1 탆 or less, and is required up to 100 nm or less. This narrower design rule results in shorter channel lengths, which results in a lower refresh time.

Recently, a STAR (STep gated Asymetric Recess) process has been proposed and used as part of increasing the channel length of a transistor in a DRAM device manufacturing process.

Hereinafter, a method of forming a gate electrode of a semiconductor device using a general STAR process will be described with reference to FIGS. 1A to 1F. 1A-1F are cross-sectional views of the process.

First, as shown in FIG. 1A, the pad oxide film 11 and the pad nitride film 12 are sequentially deposited on the semiconductor substrate 10.

Subsequently, as illustrated in FIG. 1B, a photolithography process 13 may be performed to etch the pad nitride layer 12, the pad oxide layer 11, and the substrate 10 to form a trench 14.

Subsequently, as shown in FIG. 1C, the HDP (High Density Plasma) oxide film 15 is deposited to fill the trench 14, and then a CMP (Chemical Mechanical Polishing) process is performed to form a device isolation film.

Subsequently, as shown in FIG. 1D, the strip process selectively removes the pad nitride film 12 and the pad oxide film 11.

Subsequently, as shown in FIG. 1E, the bottom anti-reflection coating (BARC) film 17 and the photoresist film are sequentially applied, followed by an exposure and development process using a photo mask to perform photoresist pattern (hereinafter, 18, which is referred to as a STAR mask.

Subsequently, as illustrated in FIG. 1F, an etching process using the STAR mask 18 is performed to etch the exposed substrate 10 and the device isolation layer 15 to form the protrusion 19 in the center of the active region.

Subsequently, a strip process is performed to remove the STAR mask 18 and the lower antireflection film 17.

However, in the method of forming a gate electrode of a semiconductor device using a STAR process according to the related art, as shown in FIG. 1D, an etching process using a STAR mask 18 is performed after removing the pad nitride layer 12 and the pad oxide layer 11. As a result, a horn (A) is generated in the active region as shown in FIG. 2 due to the step between the field region and the active region, and the uniformity of the process decreases as a subsequent etching process is performed in this state. Becomes

Accordingly, the present invention has been made to solve the above-described problems of the prior art, a process during the subsequent etching process (patterning process) by the step between the field region and the active region in the gate electrode forming process of the semiconductor device using the STAR process It is an object of the present invention to provide a method for manufacturing a semiconductor device which can prevent the uniformity of the semiconductor film from being lowered.

According to an aspect of the present invention, a pad nitride film is formed on a substrate defined by a field region and an active region, and the trench is formed by etching the pad nitride layer and the substrate of the field region. Forming an isolation layer to fill the trench, forming an etch mask to expose a portion of the pad nitride layer in the active region, and performing an etching process using the etch mask. Etching the pad nitride film, removing the etching mask, and then etching the pad nitride film as a hard mask to recess the exposed substrate to a predetermined depth; Removing and forming a protrusion in the center of the substrate manufacturing method of a semiconductor device Provide the law.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. In addition, in the drawings, the thicknesses of layers and regions are exaggerated for clarity, and in the case where the layers are said to be "on" another layer or substrate, they may be formed directly on another layer or substrate or Or a third layer may be interposed therebetween. Also, throughout the specification, the same reference numerals denote the same components.

Example

3A to 3D are cross-sectional views illustrating a method of forming a gate electrode of a semiconductor device using a STAR process in a semiconductor device manufacturing process according to an exemplary embodiment of the present invention.

First, as shown in FIG. 3A, the pad oxide film 111 and the pad nitride film 112 are sequentially deposited on the semiconductor substrate 110.

Next, a trench trench isolation (STI) process is performed to form trenches (not shown) in the field region of the semiconductor substrate 110.

Subsequently, an HDP oxide film 113 having excellent embedding characteristics is deposited as an oxide film for device isolation, so that the trench is buried.

Subsequently, the HDP oxide layer 113 is planarized to the same height by the entire surface etching process such as the CMP process.

Subsequently, the lower anti-reflection film 114 and the photoresist film are applied to the entire top surface of the planarized structure, and then the exposure and development processes using the photo mask are performed to form the STAR mask 115.

Subsequently, as illustrated in FIG. 3B, the etching process 116 using the STAR mask 115 is performed to etch the lower anti-reflection film 114, the pad nitride film 112, and the pad oxide film 111. In this case, a portion of the device isolation layer 113 exposed by the etching process 116 is etched.

Subsequently, as shown in FIG. 3C, a strip process is performed to remove the STAR mask 115 (see FIG. 3B) and the lower anti-reflection film 114.

Subsequently, an etching process 117 using the etched pad nitride layer 112 as a hard mask is performed in FIG. 3B to recess the exposed substrate 110 to a predetermined depth. In this case, a portion of the device isolation layer 113 exposed by the etching process 117 is etched to a predetermined depth.

Subsequently, as illustrated in FIG. 3C, an etching process 118 using H ₃ PO ₄ is performed to remove the pad nitride layer 112.

Next, the pad oxide film 111 is removed. As a result, the center portion of the substrate 110 in the active region protrudes, as shown in the drawing, to form a protrusion 119 having a predetermined size.

Meanwhile, before performing the etching process 118, an oxidation process may be performed to prevent damage to the substrate 110. As a result, a silicon oxide layer may be formed on the exposed upper surface of the substrate 110, thereby minimizing damage to the exposed substrate 110.

Although the technical spirit of the present invention has been described in detail in the preferred embodiments, it should be noted that the above-described embodiments are for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, according to the present invention, after forming the device isolation film, a STAR mask is formed while the pad nitride film is left as it is, and the pad nitride film is first etched using the thus formed STAR mask, and then the etched pad nitride film is The etching process using the hard mask is formed to form a protrusion in the center of the substrate, and thus the uniformity of the process during the subsequent etching process (patterning process) is performed by the step between the field region and the active region during the gate electrode formation process of the semiconductor device using the STAR process Degradation can be prevented.

Claims (4)

Forming a pad nitride film on the substrate defined by the field region and the active region; Etching the pad nitride layer and the substrate in the field region to form a trench; Forming an isolation layer to fill the trench; Forming an etch mask to expose a portion of the pad nitride layer in the active region; Etching the exposed pad nitride layer by performing an etching process using the etching mask; Removing the etching mask and recessing the exposed substrate to a predetermined depth by performing an etching process using the etched pad nitride layer as a hard mask; And Removing the pad nitride layer to form a protrusion at a center portion of the substrate; Method of manufacturing a semiconductor device comprising a. The method of claim 1, And forming a pad oxide film on the substrate before forming the pad nitride film. The method according to claim 1 or 2, And forming an oxide film on the exposed substrate by performing an oxidation process after the recessing of the substrate. The method according to claim 1 or 2, The pad nitride film removing process is performed using H ₃ PO ₄ .

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