JPH0246458A - Mask seam matching pattern - Google Patents

Abstract

PURPOSE:To estimate and decide the center of a pattern and to read mismatching of mask seams even if a base pattern is unclear by using the combination of circular patterns for matching a substrate pattern and a mask pattern. CONSTITUTION:The foundation substrate pattern 1 and the mask pattern 2 are combined to form a circular pattern. When they are matched normally, their middle points are coaxial, and the deviation from the points in all directions of the patterns is equal. Figure (b) shows that the pattern 2 is deviat ed in the direction X(+), and figure (c) shows that the pattern 2 is deviated in the directions of X(+) and Y(-). The pitch is decreased to increase the number of circles in the directions X and Y, thereby obtaining detailed informa tion. Since the gap between pattern edges is not detected but the center of the circular patterns is estimated to decide mismatching of mask seams, the unclear pattern 1 can be read out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mask alignment pattern, and more particularly to a mask alignment pattern used in the manufacture of semiconductor devices.

[Conventional technology]

Photolithography technology is often used in the manufacture of semiconductor devices. In photolithography, a mask pattern is transferred to a photoresist film coated on a base substrate, and in this case, alignment patterns are provided on both the base substrate and the mask for alignment.

As shown in FIG. 3, the alignment pattern may be one in which both the base substrate pattern 6 and the mask pattern 7 are square, and for example, the mask pattern 7 may fit inside the base substrate pattern 6, or the pattern shown in FIG. As shown in FIG. 2, there is a method in which a bar-shaped base pattern 8 and a mask pattern 9 are arranged at a predetermined interval, and the amount of misalignment in overlay is directly read.

[Problem to be solved by the invention]

The conventional alignment pattern described above uses the gap between the edges of the underlying substrate pattern and the mask pattern to read alignment errors. For this reason, if the underlying substrate pattern becomes unclear due to film growth or the pattern edges become blurred, the gaps between the pattern edges become unclear.
The drawback was that it was difficult to read the misaligned scenery.

[Means to solve the problem]

The mask alignment pattern of the present invention is composed of a combination of a matching pattern used to check the alignment between a pattern on a base substrate and a pattern on a mask, or a circular pattern.

〔Example〕

To FIG. 1 (Xl) - <(>) is a schematic plan view for explaining the a) first g) embodiment of the present invention.

In the present invention, both the base substrate pattern 1 and the mask pattern 2 are circular.

FIG. 1(a) shows when the alignment is performed normally;
In this case, the shifting star is Cero, and the pattern in the middle becomes concentric circles.

Figures 1 (1:l) and (C) show cases where misalignment occurs; Figure 1 (1) shows a shift in the X (+) direction, and Figure 1 (C> indicates a deviation in the X (+) and Y (-) directions.Here, if the center deviation bit is 0.57.zm in both the X and Y directions, then
), 0,51-trn in the X(+) direction, Fig. 1(
In C), there is a deviation of 0.571 m or more in the X (+) direction and 1ζ of 0.5/lrn or more in the Y (-) direction.

If you need more information, reduce the pitch and press
, just increase the number of circles in the Y direction. Even if the underlying substrate pattern is unclear, if it is circular, it is relatively easy to guess the center. 3. In this embodiment, it is determined that the center of two aligned circular patterns is shifted in the X and Y directions. Since it is easy to apply, it is effective when the underlying pattern is unclear.

FIGS. 2(a) to 2(C) are schematic plan views for explaining a second embodiment of the present invention.

The difference between the second embodiment and the first embodiment is that the central circular pattern in FIG. 1 is omitted. Instead, the underlying substrate pattern 3 and mask pattern 4 are
In the (+) and (-) directions of X and Y, patterns are arranged so as to be offset from the center by the alignment margin 5.

No. 2121(a) shows the case of l/1 sound being shifted or cello.

The 2nd LK (a>, (G)) shows the case where there is a misalignment of only 1 note, the 21st XI (c) shows the case where there is a misalignment within the alignment margin, and the 21st XI (c) shows the case where there is a misalignment of only 1 note. Indicates a case where the deviation exceeds .

This embodiment has the advantage that it is possible to judge at a glance whether the alignment between the underlying substrate pattern and the mask pattern is good or bad.

〔Effect of the invention〕

As explained above, the present invention uses a combination of circular patterns as an alignment pattern and judges misalignment by estimating the center of the circular pattern rather than the gap between the pattern edges, so the underlying substrate pattern is unclear. Even so, it has the effect of making it possible to read the misalignment.

... Alignment margin, 6... Base board pattern, 7
...Mask pattern, 8... Base board pattern, 9
・Mask pattern.

Claims (1)

[Claims] A mask alignment pattern characterized in that a matching pattern used to match the alignment between a pattern on a base substrate and a pattern on a mask is composed of a combination of circular patterns.