JP2001102285A - Aligning mark - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress increase in the formation area of an aligning mark use for an exposing method using a scanning transfer light aligner and an electron beam aligner. SOLUTION: Two 1st line patterns 101 are formed side by side in parallel along their length. Six 2nd line patterns 102, which are perpendicular to the length of the 1st line patterns 101, are formed on both sides of the 1st line patterns 101 across the width of the 1st line patterns 101. Three 3rd line patterns 103, which are parallel along the length of the 1st line patterns 101, are formed on both sides of the 2nd line patterns 102 across the width of the 1st line patterns 101.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an alignment mark used for exposing a pattern on the same resist on a chip using a scan transfer type light exposure apparatus and a charged beam exposure apparatus.

[0002]

2. Description of the Related Art As the integration of LSI devices advances, the demands on the accuracy and throughput of a lithography apparatus used for manufacturing LSIs have become more and more severe. In optical lithography, it has been widely used for device production utilizing high throughput. In recent years, in order to cope with miniaturization of patterns, shortening of the wavelength of an exposure light source and adoption of a scan transfer exposure method have been adopted. However, there are many issues to achieve this, and the technology has not been established. On the other hand, EB lithography has much higher resolution than optical lithography, but has no advantage in throughput even if a batch exposure (called cell projection, character projection, etc.) method is used.

Therefore, it is considered that the most realistic way to introduce the EB direct exposure technique is to first use a mix-and-match method that selectively uses the lithography in accordance with the application with the photolithography. In particular, when performing the same layer mix and match, the overlay exposure accuracy between the same layers becomes important. However, conventionally, when performing the overlay EB exposure, an EB unique, for example, a cross overlay mark (EB mark) 1001 as shown in FIG. 8 is required separately from the mark used in the optical stepper. New space must be secured for placement.

To solve these problems, a method of using a one-dimensional optical mark 1101 as an EB mark as shown in FIG. 9 has been attempted. However, in this method, the optical mark 1101 is larger than the conventional EB mark size, so that there are problems such as a long scan time and a scan that reaches a part other than the mark part, so that a resist remains in an unnecessary part.

On the other hand, the mark shape of an optical mark is changed from a one-dimensional mark to a two-dimensional mark 1201, 1202 as shown in FIG.
Is becoming mainstream. The two-dimensional mark has such a shape that the mark can be easily detected by the EB. However, the same problem as detecting a one-dimensional mark also occurs in a two-dimensional mark. Therefore, in order to shorten the mark detection time and eliminate unnecessary resist residues generated by the EB scan even in the case of a two-dimensional mark, it is necessary to arrange the mark in the optical mark area so as to be easily detected by the EB.

[0006]

As described above, a mix-and-scan type light exposure apparatus and an electron beam exposure apparatus are separately used, such as exposing a relatively coarse pattern with light and exposing a fine pattern with an electron beam. When performing match exposure, there is a problem that an EB mark is required separately from the optical mark, and a space for arranging the EB mark must be newly provided.

The present invention has been made in view of the above circumstances, and has as its object to provide an alignment mark used in an exposure method using a scan transfer type light exposure apparatus and an electron beam exposure apparatus. An object of the present invention is to provide an alignment mark that can suppress an increase in the formation area.

[0008]

Means for Solving the Problems [Configuration] The present invention is configured as follows to achieve the above object.

(1) According to the present invention (claim 1), a plurality of first linear patterns arranged in parallel in a direction perpendicular to the longitudinal direction, and the length of the first linear patterns And a plurality of second linear patterns whose longitudinal direction is orthogonal to the longitudinal direction of the first linear pattern. It is characterized by comprising a first mark to be used and a second mark formed in a formation area of the first mark and used for alignment of charged beam exposure.

Preferred embodiments of the present invention are described below.
The first and second marks are arranged at four corners of a chip region arranged and formed on a semiconductor wafer. The second mark is formed in the formation area of the first linear pattern or the second linear pattern, and is formed in parallel with a direction perpendicular to the longitudinal direction of the linear pattern in the formed area. And a plurality of linear patterns orthogonal to the longitudinal direction of the linear pattern in the region where the longitudinal direction is formed. The second mark is composed of a pattern connecting adjacent linear patterns and one part of the first linear pattern and the second linear pattern.

[Operation] The present invention has the following operation and effects by the above configuration.

According to the present invention, since the second mark (charged beam mark) is incorporated in the formation area of the first mark (light mark), the increase in the formation area of the alignment mark can be suppressed. .

Further, since the light exposure and the charged beam exposure are performed using dedicated alignment marks (first and second marks), unlike the conventional method using the light mark as the EB mark, The problem that the overlay exposure accuracy is reduced does not occur.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a view showing an alignment mark according to a first embodiment of the present invention. FIG. 1A is a diagram showing a configuration of a positioning mark, and FIG.
(B) is a diagram showing the arrangement of the alignment marks in the chip.

The alignment mark 100 of this embodiment is
An alignment mark (hereinafter, referred to as an optical mark) used at the time of light exposure, and an alignment mark formed in an area where the optical mark is formed.
And an alignment mark (hereinafter, referred to as an EB mark) used for the B exposure.

As shown in FIG. 1A, two first line patterns 101 (EB marks) are formed in parallel in a direction parallel to the longitudinal direction. The length of the first line pattern 101 in the longitudinal direction is 30 μm.
m, the interval between two adjacent line patterns is 6 μm.

Each of the pair of first line patterns 101 is arranged on both sides of the pair of first line patterns 101 so as to sandwich the width direction of the first line pattern 101 in a direction parallel to the longitudinal direction of the first line pattern 101. Six second line patterns (first linear patterns) 102 are formed. In addition, the longitudinal direction of the first line pattern 101,
The longitudinal direction of the second line pattern 102 is orthogonal. The size of this second line pattern 102 in the longitudinal direction is 21 μm, and two adjacent second line patterns 1
02 is 6 μm. The distance between the adjacent first line pattern 101 and second line pattern 102 is 3 μm.

3 are arranged on both sides of the second line pattern 102 in a direction parallel to the longitudinal direction of the second line pattern 102 so as to sandwich the width direction of the first line pattern 101. A third line pattern (second linear pattern) 103 of the book is formed.
In addition, the longitudinal direction of the second line pattern 102 and the third
Is orthogonal to the longitudinal direction of the line pattern 103.
The distance between the adjacent second line pattern 102 and third line pattern 103 is 6 μm.

The alignment mark 100 has a structure in which the second and third line patterns 102 and 103 are used as optical marks (first marks) for die-by-die alignment, and two first line patterns are used. 101 is E
It becomes an EB mark (second mark) for B exposure. As shown in FIG. 1A, the alignment mark 100 is formed on the dicing line 2 outside the device region 201 of the chip.
02 are arranged at four corners.

The alignment at the time of EB exposure will be described with reference to FIG. The first line pattern 1 is formed so as to include a space between the two second line patterns 102.
01 is scanned in the horizontal direction 304 to obtain horizontal coordinates.
Then, the two first line patterns 101 and the space therebetween are scanned in the vertical direction 305 to obtain the vertical coordinates.

When scanning in the vertical direction, 18
It is preferable to perform a scan of at least μm. Even if the first line pattern 101 is scanned by 18 μm or more, there is only one space. However, if the second line pattern 102 is scanned by mistake, two or more spaces are scanned. Can be determined.

When scanning in the horizontal direction, 12
By scanning over μm, the deviation can be easily determined.

If the horizontal mark detection accuracy cannot be obtained, the number of the third line patterns is increased, and if the vertical mark detection accuracy is not obtained, the second line pattern is used. In order to obtain a two-dimensional position at the center of a mark using a conventional mark, it is necessary to scan all the lines. However, if a part of the two first line patterns is scanned as described above, the two lines must be scanned. Dimensional positions can be determined.

If the addition of a line to a conventional mark does not provide mark detection accuracy with an optical stepper,
By making the second line pattern long, sufficient detection accuracy can be obtained. Further, in this mark, since the two-dimensional coordinates are obtained by the first line pattern near the center of the mark, the remaining resist due to the EB scan can be contained within the range of the mark, and does not affect other patterns.

The lines and spaces forming the marks are not limited to 6 μm. The widths need not be the same. Alternatively, a mark rotated by 90 degrees may be used. Further, the cross-sectional shape of the mark may be any mark using a step or a mark using a difference in material as long as the contrast of the detection signal can be obtained.

Next, a method of forming the alignment mark 100 will be described.

First, a mask having a pattern corresponding to the pattern in which the alignment marks 100 are arranged at four positions of the chip is set on a mask stage of an exposure apparatus, and the wafer coated with the negative resist is exposed to light.

Next, after developing the negative type resist to form a resist pattern, the wafer is subjected to RIE (Reactive Ion) using the resist pattern as a mask.
Etching is performed by an (Etching) method to form grooves as first to third line patterns 101, 102, and 103. The depth of this groove is, for example, 0.3 μm.

Finally, the resist pattern is carbonized by an O ₂ asher and peeled off to form a positioning mark 10.
0 is completed.

It should be noted that alignment marks of other patterns than this alignment mark 100 may be formed, but the second and third line patterns 102 and 10 to be optical marks can be formed.
3 and the first line pattern 101 serving as an EB mark have the same center coordinates, and the second and third line patterns 102 and 103 and the first line pattern 101
It is preferable to form a pattern that becomes a line-symmetric pattern from the center coordinates.

The alignment mark 1 constructed as described above
According to 00, the first line pattern 103 serving as the EB mark is incorporated in the formation area of the line patterns 102 and 103 of the second and bases 3 serving as the optical mark. Increase can be suppressed.

The second and third line patterns 10
Since the second line 103 and the first line pattern 101 can be formed by exposure using the same resist, a reduction in overlay exposure accuracy can be suppressed.

Further, the light exposure and the charged beam exposure are performed using dedicated alignment marks (light marks 102, 103,
Since this is performed using the EB mark 101), unlike the conventional method using an optical mark as the EB mark, there is no problem that the overlay exposure accuracy is reduced.

By the way, when light exposure / electron beam exposure are mixed, in particular, it is conceivable that a large number of marks for electron beam and light exposure must be arranged. By forming the alignment marks in substantially the same region, the area occupied by the marks in the chip can be reduced. As a result, a large number of marks can be arranged in a chip.

[Second Embodiment] FIG. 3 is a diagram showing a configuration of an alignment mark according to a second embodiment of the present invention. The difference between the alignment mark shown in the present embodiment and the first embodiment is that the alignment mark is formed in a shape as if the first, second and third line patterns are taken in the longitudinal direction. In other words, the first and second 6 μm-wide first and second
And the third line pattern is composed of two thin lines. The width of the line is 0.5 μm.

According to this embodiment, dust can be reduced by reducing the width of the line and the etching area. The method of obtaining the coordinates of the mark is performed by scanning the horizontal direction 404 and the vertical direction 405 as in the first embodiment.

[Third Embodiment] FIG. 4 is a diagram showing a configuration of an alignment mark according to a second embodiment of the present invention. The difference from the first embodiment is that, as shown in FIG. 4, the line pattern is the first, second and third line & space 5.
01, 502, and 503. First, second and third line & space patterns 501,
Reference numerals 502 and 503 are composed of six lines. The first, second and third line & space patterns 5
The width of the lines constituting 01, 502 and 503 is 0.5 μm
m, and the width of the space is 0.6 μm.

As in the second embodiment, the alignment mark of the present embodiment is a mark that reduces the dust by reducing the width of the line and reducing the etching area. The method of finding the coordinates of the mark is the same as in the first embodiment. Note that the widths of the lines and spaces are not limited to the above.

[Fourth Embodiment] FIG. 5 is a diagram showing a configuration of an alignment mark according to a second embodiment of the present invention. The difference from the first embodiment is that, as shown in FIG. 5, the line patterns are the first, second and third dot patterns 601,
602 and 603. The size of the dots is 1.3 μm wide and 6 μm high, and the dot pitch is 1 horizontal.
It is 2 μm vertically 8 μm.

The alignment mark of the present embodiment is a mark in which the width of the line is narrowed, the etching area is reduced, and the dust is reduced, as in the second embodiment. The method of finding the coordinates of the mark is the same as in the first embodiment. In addition,
The size and pitch of the dots are not limited to the above.

[Fifth Embodiment] FIGS. 6 and 7 are views showing alignment marks according to a fifth embodiment of the present invention.
FIGS. 6A and 7A are views showing the configuration of the alignment mark, and FIGS. 6B and 7B are views for explaining the alignment at the time of EB exposure.

The difference from the first embodiment is shown in FIGS.
As shown in (a), patterns 701, 9 connecting second line patterns 702, 902 and third line patterns 703, 903 forming a conventional two-dimensional mark.
01 means that a part of the EB mark is formed. In the alignment mark shown in FIG. 6A, the second line pattern 702 connected to the pattern 701 is a part of the EB mark. Further, in the alignment mark shown in FIG.
Is a part of the EB mark.

In the case of performing EB exposure alignment, FIG.
(B), as shown in FIG.
4 or the vertical direction 805, 905.

By connecting at least one line constituting the conventional optical mark, scanning can be easily performed by EB. This embodiment can be applied to the second to fourth embodiments.

It should be noted that the present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the scope of the invention.

[0047]

As described above, according to the present invention, since the second mark (charged beam mark) is incorporated in the formation area of the first mark (optical mark), the position of the alignment mark can be reduced. An increase in the formation region can be suppressed.

Further, since the light exposure and the charged beam exposure are performed using dedicated alignment marks (first and second marks), unlike the conventional method using the light mark as the EB mark, The problem that the overlay exposure accuracy is reduced does not occur.

[Brief description of the drawings]

FIG. 1 is a view showing an alignment mark according to a first embodiment.

FIG. 2 is a view for explaining alignment using the alignment marks shown in FIG.

FIG. 3 is a plan view showing a configuration of an alignment mark according to a second embodiment.

FIG. 4 is a plan view showing a configuration of an alignment mark according to a third embodiment.

FIG. 5 is a plan view showing a configuration of an alignment mark according to a fourth embodiment.

FIG. 6 is a view showing an alignment mark according to a fifth embodiment.

FIG. 7 is a view showing an alignment mark according to a fifth embodiment.

FIG. 8 is a plan view showing a conventional EB mark.

FIG. 9 is a plan view showing a conventional optical mark.

FIG. 10 is a plan view showing a conventional optical mark.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 alignment mark 101 first line pattern 102 second line pattern 103 third line pattern 201 device region 202 dicing line

Claims (4)

[Claims] A plurality of first linear patterns arranged in parallel in a direction perpendicular to a longitudinal direction;
A plurality of second line-shaped patterns arranged in parallel in a direction parallel to the longitudinal direction of the linear pattern, and the longitudinal direction is orthogonal to the longitudinal direction of the first linear pattern, A first mark used for alignment of light exposure, and a second mark formed in a formation area of the first mark and used for alignment of charged beam exposure are provided. Alignment mark. 2. The alignment mark according to claim 1, wherein said first and second marks are arranged at four corners of a chip region arranged and formed on a semiconductor wafer. 3. The second mark is formed in a formation area of the first linear pattern or the second linear pattern, and is formed in a direction perpendicular to a longitudinal direction of the linear pattern in the formed area. 2. The alignment mark according to claim 1, wherein the alignment mark is formed of a plurality of linear patterns formed in parallel with each other and orthogonal to the longitudinal direction of the linear pattern in a region where the longitudinal direction is formed. . 4. The method according to claim 1, wherein the second mark comprises a pattern connecting adjacent linear patterns, and a part of one of the first linear pattern and the second linear pattern. The alignment mark according to claim 1, wherein the alignment mark is formed.