JPS6348420B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a relative position detection pattern used in a photolithography process for manufacturing semiconductor devices such as semiconductor integrated circuits.

Conventional Structures and Problems In the manufacturing process of semiconductor devices such as semiconductor integrated circuits, multiple photolithography steps are generally required to form selective diffusion masks, contact windows, wiring layers, etc. will be held. A relative position detection pattern is used to detect whether a pattern has been accurately formed at a predetermined position in each photolithography process.

A conventional relative position detection pattern will be explained with reference to FIG. The first relative position detection pattern 1 formed on the first mask causes the relative position detection pattern 1 to be applied to a silicon dioxide film or the like formed on the semiconductor substrate.
After etching the second relative position detection pattern 2 formed on the second mask, the second relative position detection pattern 2 is formed on the semiconductor substrate. mask pattern and the second
The relative position of the mask pattern was detected. In this case, the pair of first and second relative position detection patterns can only detect relative positions in one direction. Therefore, in order to detect the relative positions of the first and second mask patterns, it was necessary to separately form two other sets of relative position detection patterns formed in directions perpendicular to each other. Manufacturing a semiconductor device requires several to ten or more masks, and when two sets of relative position detection patterns are formed on each mask, the occupied area becomes large and the chip size becomes large. Moreover, when ten or more sets of patterns are formed, there is a drawback that it takes time to search unless the two sets of patterns formed on the same mask are formed adjacently. Note that pattern 3 in FIG. 1b shows another pattern example formed on the first mask,
Pattern 4 shows another example of a pattern to be formed on the second mask, and when using these patterns 3 and 4, the same problem as when using patterns 1 and 2 occurs.

OBJECTS OF THE INVENTION In view of these conventional problems, an object of the present invention is to provide a relative position detection pattern that can detect relative positions in two different directions using a set of relative position detection patterns.

Structure of the Invention The present invention provides a plurality of pieces having predetermined intervals, having components parallel to one direction, and having at least one end end position, that is, the length in the long side direction, continuously changing by a predetermined length. A first pattern consisting of a first pattern and a second pattern formed on an extension line in the long side direction of the first pattern at a predetermined interval from the end point position where the first pattern has a different length. constitutes a relative position detection pattern, includes at least a component parallel to the first pattern, and includes a component parallel to the first pattern;
a plurality of third patterns having an interval different from the pattern interval; and a fourth pattern located between the first and second patterns and including a component orthogonal to the first and second patterns. Two relative position detection patterns are configured, and a set of first and second relative position detection patterns makes it possible to detect relative positions in two orthogonal directions.

Description of examples FIG. 2 shows a first embodiment of the present invention.

2. FIGS. 11 and 12 show the first position detection patterns 13 and 14 formed on the first mask.
shows the second position detection pattern formed on the second mask, and FIG. 2 shows a state in which the first position detection pattern and the second position detection pattern are accurately aligned. In other words, the first position detection pattern has a predetermined interval l ₁ and is arranged in one direction (y direction).
a plurality of first patterns 11 each having a component parallel to , and having different end points at one end, and a second pattern having a component parallel to the one direction (y direction) and having a predetermined distance _l3 from the end point position. It is formed from a pattern 12. The interval between the first pattern 11 and the second pattern 12 is constant, and the position of each interval is in the direction (y
direction) by △l. said interval
l ₁ and l ₃ may have any size that allows pattern formation, but Δl determines the reading position accuracy in the y direction. The second position detection pattern includes a plurality of third patterns 13 having a different interval l ₂ from the first pattern and having a component parallel to one direction (y direction).
and a fourth pattern 14 located on the first and second intervals and having a component in the direction (x direction) perpendicular to the third pattern.

In this embodiment, position detection in the x direction is performed based on the relative positions of the first and third patterns, and position detection in the y direction is performed based on the interval between the first and second patterns and the relative position of the fourth pattern. That is, the x direction is the first
For example, when the n-th first and third patterns from the left are aligned in a straight line in the y direction, the second position detection pattern is nx(l ₂ −l ₁ ) to the left (+x direction). Also y
The direction is that the interval between the first and second patterns is △l in the y direction.
Since they are formed at different intervals, the distance and the fourth
From the point where the pattern matches, that is, the second
The positional deviation is 0 when the above-mentioned interval and the fourth pattern match in pattern 12' in the center of the pattern.
, it means that when the mth pattern on the left side from the center matches, the second position detection pattern is shifted upward (+y direction) by mxΔl.

FIG. 3 shows a second embodiment of the invention.

The first patterns 11, 16 and 17, the second pattern 12 and the fourth pattern 14 are similar to the first embodiment, but the third pattern 15 has first patterns on both sides of each of the first patterns. For example, for two patterns having parallel components in the same direction as the first patterns 16 and 17, the third pattern 18
and 19, 19 and 20 are formed. The first pattern 16 is located in the middle between the third patterns 18 and 19, and the other first pattern 17 is formed to be shifted by Δl to the left from the center of the third patterns 19 and 20. The relationship between the other first and third patterns is also a predetermined distance n△l (n=0, 1, 2...n) in the x direction.
Form it in a staggered manner. Position detection in the x direction is performed by the third
When the first pattern located at the center of the pattern is detected and aligned accurately, the first pattern is detected.
Let the amount of deviation nΔl of the third pattern be the amount of deviation in the x direction.

FIG. 4 shows a third embodiment of the third pattern. When the first and second position detection patterns formed on a photomask are transferred and formed on a semiconductor substrate, the dimensions of each pattern change and the relative position detection sensitivity deteriorates. As shown in FIG. 4, the widths of the third patterns 18, 19, 20 adjacent to the first patterns 16, 17 are changed so that the detection sensitivity does not deteriorate even if the pattern dimensions change. Also, contrary to FIG. 4, the first pattern 16,
The pattern width of 17 may be varied.

5 and 6 show fourth and fifth embodiments.

5 and 6, in order to improve accuracy in the y direction, two sets of patterns are formed by horizontally inverting the pattern in FIG. 2 and paralleling the pattern in FIG. 2 vertically or horizontally. As shown in FIG. 7, when the rotational error between the first and third relative position detection patterns is large, in one set of patterns, the first pattern 11' and the second pattern 12 as shown in FIG. With the fourth pattern 14', position detection may become impossible. In the embodiments shown in FIGS. 5 and 6, even if a rotational error occurs, highly accurate position detection is possible from the average value of the two sets of position detection patterns.

FIG. 8 shows another embodiment of the first and second patterns. Opposing patterns 21 and 22, 23 and 24
It goes without saying that the pattern shape may be different or may be shifted from the extension line of the first pattern.

FIG. 9 shows a fourth embodiment of the present invention.

The first relative position detection pattern includes a first pattern 11 and a second pattern 12 as in the first embodiment.
Consisting of The second relative position detection pattern is the third relative position detection pattern.
A fifth pattern is formed by overlapping the third pattern 13'' of the example (Fig. 4) and the fourth pattern 14'' of the first example.
It consists of a pattern 25. In this embodiment, the fifth pattern is formed between the first and second patterns.
The relative position in the y direction can be detected from the orthogonal component 14'' of the pattern, and the relative position in the x direction can be detected from the parallel component of the first pattern or the second pattern and the fifth pattern 13''.

Effects of the Invention According to the method of the present invention, position detection in two directions is possible using a set of patterns formed in one direction.
Compared to the conventional example, 1. The area occupied by the position detection pattern is smaller. 2. Detection is possible with one set of patterns, and there is no need to search for two sets of patterns formed separately and independently in two directions as in the conventional example. 3. By forming two sets in succession as shown in FIGS. 5 and 6, there is an advantage that position detection can be performed with less reading errors due to rotational errors.

[Brief explanation of the drawing]

Figures 1a and 1b are diagrams for explaining conventional mask alignment patterns, and Figures 2 to 6 are pattern diagrams for explaining other embodiments of the present invention, showing the aligned state. FIG. 7 is a diagram showing another embodiment of the present invention with a large rotation error, and FIGS. 8a and b are diagrams showing another embodiment of the first and second patterns of the present invention. FIG. 9 is a pattern diagram of still another embodiment of the present invention. 11, 12, 11'...first position detection pattern, 13, 14, 14'...second position detection pattern.

Claims (1)

[Claims] 1. A plurality of pieces having a predetermined interval and parallel components in one direction, and in which the end point position of at least one end, that is, the length in the long side direction, continuously changes by a predetermined length. A first pattern and a second pattern formed with a predetermined same interval on an extended line in the long side direction of the first pattern from the end point position having a different length of the first pattern. a first relative position detection pattern, a plurality of third patterns including a component parallel to the long side direction of the first pattern and having an interval different from the first pattern interval; and a second relative position detection pattern consisting of a fourth pattern located between the second patterns and including a component orthogonal to the first and second patterns. . 2. The relative position detection pattern according to claim 1, wherein the line widths of opposing parallel portions of the first or third pattern are different at least in the parallel region. 3 Above and below or to the left and right of the first and second relative position detection patterns, patterns are formed by inverting the first and second relative position detection patterns with an axis parallel to the long side direction of the first pattern. 2. The relative position detection pattern according to claim 1, wherein the patterns are formed in parallel. 4. The relative position detection pattern according to claim 1, wherein the second relative position detection pattern is composed of a single fifth pattern that is a combination of the third pattern and the fourth pattern.