Mask pattern of semiconductor device and manufacturing method thereof

Provided is a mask pattern of a semiconductor device. The mask pattern includes a plurality of main patterns and a plurality of assistance patterns. The main patterns are adjacent to one another. The assistance pattern is disposed on at least one of an end portion and a middle portion of each of the main patterns and has a line width greater than that of the main pattern. The assistance patterns are staggered.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2006-0068528 (filed on Jul. 21, 2006), which is hereby incorporated by reference in its entirety.

BACKGROUND

The technology of manufacturing a mask pattern greatly affects the accuracy of a pattern formed on the semiconductor substrate.

Especially, if optical proximity effect of the mask pattern is not appropriately considered, the line width of the pattern is distorted during a photo lithography process, causing the linearity of the critical dimension to be short.

In addition, as a semiconductor device is miniaturized, the pattern is damaged by the optical proximity effect related to adjacent patterns during the photo lithography process.

Hence, various methods, which minimize the distortion phenomenon of light, such as optical proximity correction (OPC) and phase shifting mask technologies are being employed. The OPC technology compensates for the problem of light diffraction using a pattern, and the phase shifting mask technology improves an optical contrast to enhance the resolution.

Although the various methods are employed, the resolution problem of fine line widths is not easily solved. As a result, a photoresist layer pattern is chemically and physically stressed during the photo lithography process. The capillary phenomenon generated during a development process is a representative example. The greater the aspect ratio of the height to the width of the pattern, for resolution, and the fineness of a line width pitch, the greater the capillary phenomenon causing pattern collapse phenomenon during development, washing, and drying processes.

SUMMARY

Embodiments provide a mask pattern of a semiconductor device can prevent pattern collapse phenomenon of a portion of the mask pattern having fine line widths and a manufacturing method thereof.

In one embodiment, a mask pattern of a semiconductor device includes: a plurality of main patterns adjacent to one another; and an assistance pattern on at least one of an end portion and a middle portion of each of the main patterns, the assistance pattern having a line width greater than that of the main pattern, wherein the assistance patterns are staggered.

In another embodiment, a method of manufacturing a mask pattern of a semiconductor device includes: forming a plurality of adjacent main patterns; forming an assistance pattern on at least one of an end portion and a middle portion of each of the main patterns, the assistance pattern having a line width greater than that of the main pattern.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Before the embodiments are described, the principal of pattern collapse phenomenon will now be described.

FIG. 1is a view illustrating a development process of a photoresist layer, andFIG. 2is an image illustrating the pattern collapse phenomenon of a photoresist layer.

Referring toFIG. 1, developer (not shown) is sprayed on a semiconductor substrate100through a nozzle40of a development unit (not shown), and the photoresist layer is then developed to obtain a photoresist layer pattern (not shown) of the semiconductor substrate100.

Thereafter, through the nozzle40, deionized water50is sprayed to wash the photoresist layer pattern of the semiconductor substrate100.

After the washed semiconductor substrate100is dried, the photoresist layer pattern formed on the semiconductor substrate100is observed using a scanning electron microscope (SEM) to obtain the image as illustrated inFIG. 2.

Referring toFIG. 2, the photoresist layer pattern of the semiconductor substrate100includes a normal pattern portion20and a collapsed pattern portion30due to the capillary phenomenon during a patterning process. As such, the pattern collapse phenomenon easily occurs when a fine pattern is formed on a metal substrate, when the aspect ratio of the height to the width of a pattern is 3 or more, and when a pattern is asymmetric.

FIG. 3is a view illustrating the state of deionized water50contacting a photoresist layer pattern60during a development process, andFIG. 4is a view illustrating the shape of the photoresist layer pattern60after the deionized water is dried.

Referring toFIG. 3, when the gap between portions of the photoresist layer pattern60is narrower, the meniscus of the deionized water50in the narrow gap is higher than that of deionized water in a wider gap.

In addition, because of the force difference between the narrower gap and the wider gap, a force γ having an angle θ is transmitted toward the narrow gap.

The transmitted force is a capillary force caused by the capillary phenomenon of the deionized water50. The transmitted force is generated during a drying process of the semiconductor substrate100as illustrated inFIG. 2. Referring toFIG. 4, while the deionized water50is gradually evaporated, the photoresist layer pattern60is collapsed toward the direction of the transmitted force.

Therefore, the pattern collapse phenomenon as illustrated inFIG. 2occurs.

FIGS. 5 to 7are views illustrating a method of manufacturing a mask pattern according to an embodiment of the invention. The present invention applies to both photolithography masks (e.g., a pattern of chrome formed on a quartz plate, through which light of a predetermined wavelength is passed to cause a photochemical reaction in irradiated portions of a photoresist on a semiconductor substrate and thus transfer a layout pattern to the photoresist) and etch masks (e.g., the patterned photoresist on the semiconductor substrate). The material to be patterned using the mask can be any conventionally patterned material, but preferably comprises a metal, polysilicon, metal silicide or insulator (preferably metal or polysilicon).

Referring toFIG. 5, the mask pattern according to the embodiment includes a plurality of main patterns100. The main pattern100includes a first pattern110and a plurality of second patterns120.

The first pattern110has a line width greater than the minimum line width according to a design rule of the mask pattern and has a feature capable of connecting the second patterns120. In general, a plurality of adjacent first patterns110are parallel to one another. In some embodiments, 3, 4, 5, 6 or more adjacent first patterns110are parallel to one another (or have predetermined length portions that are parallel to one another, the predetermined length being at least 3, 5 or 10 times the width of the first patterns110).

The second pattern120has a line width less than the minimum line width and extends from the first pattern110(generally, substantially perpendicular to the first pattern110). Hence, the line width of the first pattern110is greater than that of the second pattern120. In general, each first pattern110has a plurality of second patterns120in contact therewith and extending therefrom

Also, in the case where the plurality of main patterns100are provided, the first patterns110of the main patterns100may face each other (or be parallel to each other), and the second patterns120of the main patterns100may be staggered, as illustrated inFIG. 5(e.g., a plurality of the second patterns120extending from a first first pattern110may be interleaved with a plurality of second patterns120extending from a second first pattern110).

As such, the method of manufacturing the mask pattern according to the embodiment may reduce or prevent the pattern collapse phenomenon of a photoresist layer easily occurring in a pattern region in which the adjacent main patterns100are designed, that is, in a condensed pattern region.

First, as shown inFIG. 6, a middle portion of the second pattern120is “cut,” and cut second patterns a and b are overlapped with each other (e.g., a second pattern120extending from a first first pattern110may have a cut region c a first predetermined distance from the first first pattern110and a second predetermined distance from an adjacent second first pattern110, the second predetermined distance>the first predetermined distance; preferably, all of the second patterns120between adjacent parallel first patterns110have such a “cut” region c). The “cut” region c is generally not actually cut or removed from an actual photolithography or photoresist mask, except in an electronic representation of the mask. Rather, the “cut” region c is described in the electronic representation of the mask to facilitate insertion of as assistance pattern (to be described below).

An overlapped portion c is thus generally formed at only the second pattern120having a line width less than the minimum line width. In addition, the overlapped portion c has a length larger than or equal to a predetermined threshold length (e.g., the minimum length causing an offgrid, for example, 2 nm or more).

Thereafter, referring again toFIG. 6, the size of the (overlapped) portion c may be reduced through a precise adjustment process, which may be optical, chemical and/or electrical, in accordance with techniques known to those skilled in the art. The reduction range of the overlapped portion c may be 1-2 nm.

After the size of the (overlapped) portion c is adjusted, referring toFIG. 7, a plurality of assistance patterns130are formed at the portion c and/or at an end portion of the second pattern120. The assistance pattern130is generally tetragonal, has a line width greater than that of the second pattern120, and covers (alone or with a counterpart assistance pattern130over a remaining part of portion c) the portion c. In other words, each of a plurality of assistance patterns130may be placed at ends of each second pattern120, and each of the assistance patterns130may have dimensions sufficient to cover the “cut” portion c in the second pattern120.

Hence, as described inFIG. 5, in the case where the second patterns120of the main patterns100are staggered, if the overlapped portions c along the plurality of second patterns120extending from a particular first pattern110are arranged on a horizontal line, the adjacent assistance patterns130overlap with one another. To prevent the overlaps of the assistance patterns130having line widths relatively greater than those of the second patterns120, the adjacent overlapped portions c are out of a horizontal line to be staggered. The arrangement in which the “cut” portions c are a first predetermined distance from the first first pattern110and a second predetermined distance from an adjacent second first pattern110results in staggered assistance patterns130along adjacent second patterns120(extending from adjacent parallel first and second first patterns110).

As such, the area of the second pattern120can be expanded by the assistance pattern130. Hence, when the photoresist layer is exposed and developed using the mask pattern, a portion of the photoresist layer formed using the assistance pattern130fixes or stabilizes a portion of the photoresist layer including the second pattern120. Therefore, the pattern collapse phenomenon is reduced. Although not wishing to be bound by any particular theory, it is believed that (1) forming second patterns120having line widths less than a minimum line width (or critical dimension [CD]) and (2) forming assistance patterns130at the ends of the second pattern120on a photolithography mask may result in relatively small corresponding structures in the patterned photoresist mask, which may be sufficient to stabilize the patterned photoresist mask against collapse due to the capillary phenomenon, but insufficient to result in formation o any corresponding pattern in the underlying material (e.g., a relatively standard or slightly extended overetch can remove the residual second patterns and/or assistance patterns in the photoresist mask).