KR20070064161A - Method of fabricating overlay key pattern of semiconductor device - Google Patents

Abstract

A method for forming an overlay key pattern in a semiconductor device is provided to reduce a defective by preventing inaccurate measurement of an aligning level obtained by undercut of an overlay key. An oxide film is formed on a semiconductor substrate(110), and then is patterned to form a scribe line(112) comprising a first overlay key(114). After the first overlay key is filled with a first material(116), a second material layer is formed on the scribe line comprising the first overlay key. The second material layer is etched using a mask having desired patterns, so that the second overlay key is formed in engraving pattern in an inside of the first overlay key on the scribe line.

Description

Method for forming overlay key pattern of semiconductor device {Method of Fabricating Overlay Key Pattern of Semiconductor Device}

1 is a plan view for explaining an overlay key pattern of a semiconductor device according to the prior art;

2A to 2D are cross-sectional views taken along line A-A of FIG. 1 to illustrate a method for forming an overlay key pattern of a semiconductor device according to the prior art;

3 is a plan view illustrating an overlay key pattern of a semiconductor device in accordance with an embodiment of the present invention;

4A to 4C are cross-sectional views taken along line B-B of FIG. 3 to illustrate a method of forming an overlay key pattern of a semiconductor device according to an embodiment of the present invention;

5 is a plan view illustrating an overlay key pattern of a semiconductor device in accordance with another embodiment of the present invention;

6A through 6C are cross-sectional views taken along the line C-C of FIG. 5 to illustrate a method of forming an overlay key pattern of a semiconductor device according to another exemplary embodiment of the present inventive concept.

The present invention relates to a semiconductor device, and more particularly, to a method for forming an overlay key pattern of a semiconductor device.

As semiconductor devices are highly integrated, the gap between line widths and patterns formed on a semiconductor substrate is rapidly narrowing. Accordingly, not only the margin allowed for pattern formation in the photolithography process but also the mask overlay margin for forming the pattern at the exact position of the semiconductor substrate in a precise form is rapidly decreasing.

The amount of mask overlay is determined by exposing and developing an overlay key pattern formed on the mask through scanner alignment to form an overlay key pattern formed on an area where a device of the semiconductor substrate is not formed, for example, a scribe line. Measure using overlay key pattern measurement equipment.

The overlay key is formed in every process of the semiconductor device to which the mask is applied, and is formed between the overlay key pattern formed in the previous process and the overlay key pattern formed in the current process (generally formed inside the overlay key formed in the previous process). From the relative positional relationship, the overlay degree of the overlay key pattern, that is, the degree of alignment is measured.

1 is a plan view illustrating an overlay key pattern of a semiconductor device according to the related art.

Referring to FIG. 1, a first overlay key 14 formed in a scribe line 12 on a semiconductor substrate (not shown), a first material 16 filled in the first overlay key 14, and a first overlay key 14 are provided. ) Is an overlay key pattern of a semiconductor device provided with a second overlay key 18a formed inside.

2A to 2D are cross-sectional views taken along the line A-A of FIG. 1 to explain a method for forming an overlay key pattern of a semiconductor device according to the prior art.

Referring to FIG. 2A, an oxide film is formed on the semiconductor substrate 10. The scribe line 12 including the first overlay key 14 is formed by patterning the oxide film.

Referring to FIG. 2B, after filling the first overlay key 14 with the first material 16, a second layer of material 18 is formed on the scribe line 12 including the first overlay key 14. do. The second material layer 18 is formed mainly using photoresist. The second material layer 18 is etched using the mask 30 having the predetermined patterns 31 and 32.

Referring to FIG. 2C, a second overlay key 18a is formed inside the first overlay key 14 on the scribe line 12 by etching using the mask 30 having the predetermined patterns 31 and 32. .

Referring to FIG. 2D, when the photoresist is used as the second material layer 18 used to form the second overlay key 18a, the mask 30 has a predetermined pattern 31 and 32. Undercut may occur under the second overlay key 18a due to the diffuse reflection of the light incident on the exposed portion.

The overlay key pattern of the semiconductor device formed by the above method is formed to have a rectangular box shape in which the shape of the second overlay key is a mesa type. In this case, when the photoresist is used as the material of the second overlay key, the light transmitted through the mask having the predetermined pattern for forming the second overlay key is caused by the diffuse reflection by the surface of the lower scribe line. An undercut phenomenon may occur in which the lower portion of the etch is more etched. Accordingly, there is a problem that the degree of alignment of the mask in the previous process and the current process is erroneously measured due to this undercut phenomenon.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an overlay key pattern forming method of a semiconductor device capable of preventing the misalignment of mask alignment in the previous process and the current process.

In order to achieve the above technical problem, the present invention provides a method for forming an overlay key pattern of a semiconductor device. According to this method, first a first overlay key is formed on a scribe line on a semiconductor substrate. And forming a second overlay key on the scribe line including the first overlay key, wherein the second overlay key is an intaglio pattern.

The scribe line may be formed of an oxide film containing an antireflective material. The first overlay key may be filled with silicon nitride.

The present invention also provides a method for forming an overlay key pattern of another semiconductor device. According to this method, first a first overlay key is formed on a scribe line on a semiconductor substrate. An anti-reflective coating film is formed on the scribe line including the first overlay key. Forming a second overlay key on the anti-reflective coating film, the second overlay key is characterized in that the intaglio pattern.

The scribe line may be formed of an oxide film. The first overlay key may be filled with silicon nitride.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the invention to those skilled in the art. In the drawings, the thicknesses of films and regions are exaggerated for clarity. Also, if it is mentioned that the film is on another film or substrate, it may be formed directly on the other film or substrate or a third film may be interposed therebetween.

3 is a plan view illustrating an overlay key pattern of a semiconductor device in accordance with an embodiment of the present invention.

Referring to FIG. 3, a first overlay key 114 formed on a scribe line 112 on a semiconductor substrate (not shown), a first material 116 filled in the first overlay key 114, and a first overlay key 114 are provided. ) Is an overlay key pattern of a semiconductor device provided with a second material layer pattern 118a including a second overlay key 120 formed inside.

4A to 4C are cross-sectional views taken along the line B-B of FIG. 3 to illustrate a method of forming an overlay key pattern of a semiconductor device according to an embodiment of the present invention.

Referring to FIG. 4A, an oxide film is formed on the semiconductor substrate 110. By oxidizing the oxide layer, a scribe line 112 including the first overlay key 114 is formed. The oxide film may include an antireflective material.

Referring to FIG. 4B, after filling the first overlay key 114 with the first material 116, a second layer of material 118 is formed on the scribe line 112 including the first overlay key 114. do. The first material 16 may be silicon nitride (SiN). The second material layer 118 may be formed using a photoresist.

The second material layer 118 is etched using the mask 130 having the predetermined patterns 131 and 132.

Referring to FIG. 4C, the second overlay key 120 is in an intaglio pattern inside the first overlay key 114 on the scribe line 112 by etching using the mask 130 having the predetermined patterns 131 and 132. Can be formed.

5 is a plan view illustrating an overlay key pattern of a semiconductor device according to another exemplary embodiment of the present invention.

Referring to FIG. 5, on a scribe line including a first overlay key 214 formed on a scribe line (not shown) on a semiconductor substrate (not shown) and a first material 216 filled in the first overlay key 214. An anti-reflective coating (ARC) formed on the second overlay, and a second overlay of the intaglio pattern formed inside the first overlay key 214 and the first material 216 filled in the first overlay key 214. The overlay key pattern of the semiconductor device including the second material layer pattern 218a including the key 220 is provided.

6A through 6C are cross-sectional views taken along line C-C of FIG. 5 to illustrate a method of forming an overlay key pattern of a semiconductor device according to another exemplary embodiment of the present inventive concept.

Referring to FIG. 6A, an oxide film is formed on the semiconductor substrate 210. The scribe line 212 including the first overlay key 214 is formed by patterning the oxide film.

Referring to FIG. 6B, after filling the first overlay key 214 with the first material 216, a second material layer 218 is formed on the scribe line 212 including the first overlay key 214. do. The first material 216 may be silicon nitride. The second material layer 218 may be formed using a photoresist.

The second material layer 218 is etched using the mask 230 having the predetermined patterns 231 and 232.

Referring to FIG. 6C, the second overlay key 220 is in an intaglio pattern inside the first overlay key 214 on the scribe line 212 by etching using the mask 230 having the predetermined patterns 231 and 232. Can be formed.

When the overlay key pattern of the semiconductor device is formed by the method according to the embodiments of the present invention described above, the second overlay key may have an intaglio pattern unlike the conventional art in which the second overlay key is an embossed pattern. Accordingly, the undercut phenomenon occurring under the second overlay key by the diffuse reflection of the transmitted light in the exposure process for forming the second overlay key can be minimized.

In addition, since the oxide film forming the scribe line includes an antireflective material, it is possible to minimize the reflection caused by the light transmitted in the exposure process by the surface of the lower scribe line. Alternatively, since the antireflective coating layer is formed on the scribe line including the first overlay key, diffused light may not be diffused by the antireflective coating layer in the exposure process. Accordingly, undercut phenomenon occurring under the second overlay key may be prevented by the diffuse reflection of the transmitted light in the exposure process for forming the second overlay key.

Accordingly, the semiconductor device overlay may reduce the occurrence of defects by preventing misalignment of the mask due to the misalignment of the mask in the previous process and the current process due to the undercut phenomenon occurring on the lower surface of the second overlay key. A method of forming a key pattern can be provided.

As described above, according to the present invention, it is possible to provide a method for forming an overlay key pattern of a semiconductor device, which can reduce the occurrence of defects by preventing the misalignment caused by the undercut of the overlay key.

Claims (6)

Forming a first overlay key in a scribe line on the semiconductor substrate; And And forming a second overlay key on the scribe line including the first overlay key, wherein the second overlay key is an intaglio pattern. The method of claim 1, The method for forming an overlay key pattern of a semiconductor device, wherein the first overlay key is filled with silicon nitride. The method of claim 1, And the scribe line is formed of an oxide film including an antireflective material. Forming a first overlay key in a scribe line on the semiconductor substrate; Forming an anti-reflective coating on the scribe line including the first overlay key; And And forming a second overlay key on the anti-reflective coating layer, wherein the second overlay key is an intaglio pattern. The method of claim 4, wherein And the scribe line is formed of an oxide film. The method of claim 4, wherein The method for forming an overlay key pattern of a semiconductor device, wherein the first overlay key is filled with silicon nitride.

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