Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Radiation mask
Reexamination Certificate
1999-09-16
2001-07-24
Rosasco, S. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
Radiation mask
Reexamination Certificate
active
06265114
ABSTRACT:
This application claims the benefit of Korean Application No. 1802/1999 filed Jan. 21, 1999, which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a method of generating mask data in fabricating semiconductor devices. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for suppressing a proximity effect in mask fabrication.
2. Discussion of the Related Art
In a photolithographic process of the semiconductor fabrication, a photoresist is patterned by exposing the photoresist to light through a mask on a semiconductor substrate. The semiconductor substrate is then etched using the patterned photoresist. In order to form a contact hole or a via hole in the semiconductor substrate, it is imperative to pattern the photoresist without shifting hole locations and distorting a hole shape.
As a semiconductor device becomes highly integrated, a distance between contact holes and via holes becomes narrower, so that a distance between holes in a mask hole pattern is inevitably closer. Accordingly, as the distance between holes in a mask having a hole pattern becomes closer, a photoresist hole pattern distorted from the original mask hole pattern may be formed on the semiconductor substrate surface due to a proximity effect.
The proximity effect occurs when a photoresist is exposed to light, and a hole pattern on a semiconductor substrate tends to be larger than the original mask hole pattern. The light which has passed through the hole in a mask exists not only in a lower portion of the hole but also in a lower portion of the region other than the hole. This is due to its wave characteristic, wherein the light existing in lower portions of the hole as well as the region other than the hole develops a constructive interference. When an intensity of the constructively interferenced light is high enough to etch the photoresist, the photoresist is further etched an area around the original mask hole pattern, thereby deviating from the mask hole pattern. In this process, a distortion of the photoresist hole pattern from the mask hole pattern becomes larger as the distance between holes becomes closer.
FIGS. 1A through 1C
are top views of hole patterns to illustrate a proximity effect. In each drawing, a mask hole pattern
1
is shown as a solid line while a photoresist hole pattern
2
formed on a semiconductor substrate is shown as a dotted line. Since a contact hole or a via hole is formed as a square column, the mask hole pattern
1
is formed as a square shape.
FIG. 1A
shows an example for which a mask having a single hole assuming that a distance between holes is infinite, so that the photoresist is etched by only an intensity of the light passed through the hole. In other words, a constructive interference plays no role in this case. Therefore, the photoresist hole pattern
2
formed on the semiconductor substrate is the same as the mask hole pattern
1
.
In
FIG. 1B
, however, the mask hole pattern
1
has neighboring holes having a distance therebetween, so that the photoresist hole pattern
2
formed on the semiconductor substrate is further etched by a distance d due to a proximity effect. As a result, the photoresist hole pattern
2
formed is rectangular instead of square and extends in a direction toward a neighboring hole direction.
FIG. 1C
shows a distance between holes which is much narrower than that of FIG.
1
B. The photoresist hole pattern
2
formed on the semiconductor substrate is shifted by a distance d′, which is larger than d in terms of a shifted degree from the mask hole pattern
1
. Thus, the holes
2
are connected to one another, as shown in FIG.
1
C.
In order to prevent the proximity effect, a phase shift mask or an anti-reflective film has been employed in a background art. The phase shift mask has a controlled thickness and material in a light-shielding region to invert the phase of light in the light-shielding region of the phase shift mask. That is, the phase shift mask prevents a proximity effect by offsetting the light in a lower portion of the region other than the hole. However, since such a phase shift mask is expensive, it cannot be widely applied in the general process.
In another method of the background art, after an anti-reflective film is coated under the photoresist, the photoresist is patterned using a general mask. In this process, the anti-reflective film causes respective light on a lighting region and a shielding region to have opposite phases and to be offset with each other. Nonetheless, such a method still requires a coating process of the anti-reflective film.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a method of generating mask data in fabricating semiconductor devices that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
Another object of the present invention to provide a method of generating mask data in fabricating semiconductor devices, wherein mask data is generated in considering a distortion in advance, thereby eliminating a proximity effect, reducing production cost, and process steps.
Additional features and advantages of the invention will be set forth in the description which follows and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a method of generating data for a mask in fabricating a semiconductor device, the method comprising the steps of determining original mask data for a mask hole pattern on the mask, the hole pattern being formed in at least three rows, defining the mask hole pattern as first, second, and third hole patterns, wherein the first, second, and third hole patterns have first, second, and third distances between holes in first, second, and third rows, respectively, determining a degree of distortion in each row, and calculating adjusted mask data by calibrating a size of the second and third hole patterns in accordance with the distance and the degree of distortion in each row for generating a photoresist hole pattern to be the same as the mask hole pattern.
In another aspect of the present invention, a method of generating mask data in fabricating a semiconductor device, the method comprising the steps of determining first mask data for a mask hole pattern on a mask, the mask hole pattern being formed in N rows, determining a first distance between the mask hole patterns in a first row, determining a second distance between the mask hole patterns in a second row, the first distance being greater than the second distance, determining an (N−1)th distance between the mask hole patterns in an (N−1)th row, determining an Nth distance between the mask hole patterns in an Nth row, the (N−1)th distance being greater than the Nth distance, determining a first degree of distortion in the second row, determining a second degree of distortion in the third row, the second degree of distortion being greater than the first degree of distortion, determining an (N−1)th degree of distortion in the (N−1)th row, determining an Nth degree of distortion in the Nth row, the Nth degree of distortion being greater than the (N−1)th degree of distortion, and compensating the first mask data in accordance with each distance and each degree of distortion, thereby determining each mask data in each row for producing first photoresist hole patterns.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the inven
Hyundai Micro Electronic Co., Ltd.
Morgan & Lewis & Bockius, LLP
Rosasco S.
LandOfFree
Method of generating mask data in fabricating semiconductor... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of generating mask data in fabricating semiconductor..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of generating mask data in fabricating semiconductor... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2524704