KR100209363B1 - Method of manufacturing word line of semiconductor device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing word lines of a semiconductor device, and is a method for compensating the degree of distortion of word lines due to diffuse reflection at the boundary of an element isolation oxide film in an asymmetric memory unit cell structure having a T-shaped active region. The distance between the lines is shifted up and down so that the center point of the word line is coincident with the center point of the contact, making it easy to form the word line and increasing the margin of margin with other collisions around. The reliability of the operation can be improved.

Description

Word line manufacturing method of semiconductor device

1 is a design layout diagram of a semiconductor device according to the prior art.

2 is a layout diagram of a semiconductor device in which a pattern is formed using the layout of FIG.

3 is a schematic diagram for explaining a conventional manufacturing process using a cross section taken along line I-I in FIG.

4 is a design layout diagram of a semiconductor device according to the present invention.

FIG. 5 is a schematic diagram for explaining a word line manufacturing method of a semiconductor device according to the layout of FIG.

* Explanation of symbols for main parts of the drawings

1: semiconductor substrate 2: active area

3: word line 4: bit line contact

5: device isolation oxide film 6: gate oxide film

7: polycrystalline silicon layer 8: photosensitive film

10: exposure mask 11: transparent substrate

12: light blocking film pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a word line of a semiconductor device. In particular, in asymmetric cells having a T-shaped active region, a word line is compensated for damages caused by naming in consideration of occurrence of naming or the like due to a step of an element isolation oxide film. To improve the process margin with other layers by moving the word line pattern of the exposure mask toward the device isolation oxide film which causes the naching to the extent that it can be moved, taking the portion of the etched photoresist pattern corresponding to the word line into actual pattern formation. The present invention relates to a method for manufacturing word lines of semiconductor devices.

According to the recent trend toward higher integration of semiconductor devices, finer pattern formation is required, and such fine pattern formation technology is affected by the formation of a photoresist pattern serving as a mask.

The photoresist pattern may not form a fine pattern below a certain degree due to many constraints such as the precision of the exposure apparatus, the wavelength of light, and the like.

For example, the light wavelengths used are 436,365 and 248, respectively. Process resolution of reduced exposure units using phosphorus G-rays, I-rays and excimer lasers as light sources is about 0.6 , 0.3 , 0.2 The extent to which lines / spaces are about the size is the limit, and in the case of contact holes, they are larger than this.

In addition, a memory device having a unit cell composed of a capacitor and a transistor for storing charges is 0.35 when 64M DRAM or more. The following fine patterns should be processed.

When the fine pattern of the highly integrated semiconductor device is formed on the actual wafer, the pattern formed on the exposure mask does not appear as designed on the wafer, which is so severe that the cells can be highly integrated.

1 to 3 are diagrams for explaining a word line fabrication method of a semiconductor device according to the prior art, which is an example of an asymmetric cell having a T-shaped active region, and will be described with respect to each other.

First, as shown in FIG. 1, in the semiconductor device to be formed, an active region 2 having a T shape on the semiconductor substrate 1 is defined by an element isolation oxide film, and both sides of the active region 2 are formed. A word line 3 passing through the portion is formed, and a bit line contact 4 is formed in the central projecting portion of the active region 2 between the word lines 3.

When the semiconductor device is formed in accordance with the design of FIG. 1, a device having a layout as shown in FIG. 2 is formed as a whole, of which word lines 3 opposite to each other due to a step in the S portion scheduled for non-specific line contacts. Naching occurs during the photosensitive film exposure process for formation.

As shown in FIG. 3, a device isolation oxide film 5 defining a T-shaped active region 2 is formed on the semiconductor substrate 1, and a gate oxide film (2) is formed on the active region 2. 6), and the polysilicon layer 7 and the photosensitive film 8, which become word lines, are sequentially applied to the entire surface of the structure.

The light blocking film pattern 12 is then exposed using an exposure mask 10 formed at a portion of the polysilicon layer 7 corresponding to a portion intended as a word line, and then developed to develop the photoresist film 8. A pattern is formed and the polysilicon layer 7 is etched using a mask to form a word line 3.

Here, since the element isolation oxide film 5 is formed during the exposure process and has a step with the active region 2 portion, the opposite side is caused by diffuse reflection in the inclined portion S of the element isolation oxide film 5. The photosensitive film 8 is exposed and formed to be biased by dl.

The word line fabrication method of the semiconductor device according to the prior art as described above is a word line is symmetrically designed around the bit line contact in the T-shaped active region, so that the word line is diffusely reflected at the boundary of the device isolation oxide film defining the active region Naching occurs due to light, and word lines are biased toward the active area opposite the boundary of the device isolation oxide film by reflection on the inclined surface of the device isolation oxide film. Subsequent processes such as bit line contact or charge storage electrode contact, etc. In the process of the process margin is reduced, there is a problem that the process yield and the reliability of device operation is inferior.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to prevent the conductive layer, which is intended to be a word line opposite the boundary portion of an element isolation oxide film to define a T-shaped homogeneous region, from being exposed etched. The present invention provides a method for manufacturing a word line of a semiconductor device, which can increase process yield and improve process yield and reliability of device operation.

A feature of the word line fabrication method of a semiconductor device according to the present invention for achieving the above object is the step of forming a device isolation oxide film defining a T-shaped active region on the semiconductor substrate, and on the active region Forming a gate oxide film, forming a conductive layer that becomes a word line on the entire surface of the structure, forming a photosensitive film on the conductive layer, and passing through both sides of the active region, The photoresist is selectively exposed using an exposure mask in which a light shielding film pattern is formed in a portion corresponding to a portion of the conductive layer, which is a word line, to form a word line having a curved portion symmetrically with respect to the word line. Exposure in which the barrier layer pattern is moved by a predetermined distance downward from the active area with respect to the word line to be formed Forming a photoresist pattern by developing a photoresist film; and etching a conductive layer using the photoresist pattern as a mask to form word lines symmetrically formed with respect to the protruding portion of the active region. It's in the box.

Hereinafter, a word line manufacturing method of a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings.

4 and 5 are diagrams for explaining a word line manufacturing method and a pattern formation of a semiconductor device according to the present invention, an example of a semiconductor device having a T-shaped active region.

First, as shown in FIG. 4, the semiconductor device to be formed defines a T-shaped active region 2 on the semiconductor substrate 1, and word lines passing through both sides of the active region 2. (3) is formed to be biased downward with respect to the bit line contact (4) formed in the protruding portion of the lower center of the active region (2).

Such a moved word line 3 design has no margin of overlap on the design drawing with the contact hole pattern mask, or may be shorted with each other and appear as an error in semiconductor design. ) 10% of the design rule downwards relative to the bitline contact 4, e.g. 0.01 to 0.1 Move it about.

However, in this design rule, although the overlap margin is out of range, a normal word line having a process margin larger than that of a bit line contact can be obtained on an actual wafer.

That is, when the semiconductor device is formed as shown in FIG. 4, a device isolation oxide film defining a T-shaped active region is formed on the semiconductor substrate, and a gate oxide film, a polycrystalline silicon layer, and a pore film-type photosensitive film are sequentially formed on the active region. .

Next, the photoresist film is exposed using an exposure mask in which a light shielding film pattern is formed on a portion of the transparent substrate corresponding to the word line in FIG. 4, and the exposed portion is developed and removed to form a photoresist pattern.

Thereafter, the polysilicon layer is etched using the photosensitive film pattern as a mask to form word lines.

Since the word lines on the left and right sides of the active region are shifted downward by d with respect to the bit line contact in the design, as shown in FIG. 5, by the diffuse reflection in the inclined portion S of the element isolation oxide film during the exposure process, as shown in FIG. The photosensitive film on the opposite side is exposed.

Therefore, since the mask is formed downward by d, the actual position is formed downward compared to the conventional position, and as a result, the word line 3 is formed symmetrically about the bit line contact 4.

As described above, the word line fabrication method of the semiconductor device according to the present invention is a distortion of the word line due to the reflection on the inclined surface and the diffuse reflection at the boundary portion of the isolation oxide film in the asymmetric memory unit cell structure having a T-shaped active region As a method of compensating the accuracy, the distance between the lines transformed by the diffuse reflection is moved up and down so that the center point of the word line coincides with the center point of the contact, so that the word line is easily formed and the process margin with other layers around The degree is increased, there is an advantage that can improve the process yield and the reliability of device operation.

Claims (3)

Forming a device isolation oxide film defining a T-shaped active region on the semiconductor substrate, forming a gate oxide film on the active region, and forming a conductive layer that becomes a word line on the entire surface of the structure A process of forming a photoresist film on the conductive layer, and forming a word line passing through both sides of the active region and having a bent portion bilaterally symmetric with respect to the protrusion of the lower portion of the T-shape of the active region. Selectively exposing the photoresist using an exposure mask having a light blocking film pattern formed at a portion corresponding to a portion intended as a word line, and from the active region to the bit line contact for the word line to be formed by the light blocking film pattern. A protruding active region, which is a portion that causes reflection and nagging on the inclined surface of the device isolation oxide film around a predetermined portion A process of using an exposure mask which is formed by moving a predetermined distance toward an inclined device isolation oxide of the slant, a process of developing the photoresist film to form a photoresist pattern, and etching the conductive layer using the photoresist pattern as a mask to form the active region Forming a word line symmetrically with respect to the projected portion defined by the bit line contact of the semiconductor device. The method of claim 1, wherein the degree of movement of the word line is determined by 10 in the design rule. A word line manufacturing method of a semiconductor device, characterized in that to move by the following size. The method of claim 2, wherein the word line is 0.01 to 1 A word line manufacturing method of a semiconductor device, characterized in that formed by moving.