JP2009064951A - Alignment mark, alignment mark formation method, and pattern formation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form an alignment mark capable of improving superposition accuracy, and of reducing an exposure and superposition measurement processing time when a new pattern is formed by superposing a new pattern on a pattern formed by a double pattern to be exposed to light. <P>SOLUTION: This alignment mark is formed on a processing object film by using a first mask having a first graphic element and a second mask having a second graphic element in order to position a third mask. The alignment mask formed like that is provided with a plurality of third graphic elements having the same shape, one side of the third graphic element is formed with the first graphic element, and the other sides thereof are each formed with the second graphic element. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pattern forming method in a lithography process.

  In recent years, with the miniaturization of semiconductor integrated circuit devices, it has been required to form fine wiring at a fine pitch. In response to this demand, a multiple exposure process using a plurality of masks when patterning one layer is being studied. The multiple exposure process will be briefly described below.

  First, the design data is divided into two or more mask data so that the pattern pitch is relaxed, and a plurality of masks are manufactured. A resist is applied on the deposited semiconductor substrate. After aligning the semiconductor substrate, the resist film is exposed through the first mask to transfer the pattern. Similarly, the resist film is sequentially exposed through the second and subsequent masks to transfer the pattern of each mask. After the exposure of the resist film through all the masks is completed, the resist film is developed.

  As described above, when the multiple exposure process is used, a pattern with a relaxed pitch can be formed in each mask. Therefore, a fine pitch pattern can be formed by combining all the masks. However, the multiple exposure process has problems such as a reduction in proximity effect correction accuracy and a deterioration in dimensional control because the exposure light of each mask pattern affects other mask patterns.

  Therefore, in order to avoid the above problem in the multiple exposure process, a technique using double patterning has been proposed. Hereinafter, the double patterning process will be briefly described.

  First, the design data is divided into two or more mask data so that the pattern pitch is relaxed, and a plurality of masks are manufactured. A film to be processed and a film to be a hard mask are sequentially formed on the semiconductor substrate, and a resist is applied on the hard mask film. After aligning the semiconductor substrate, the resist film is exposed through the first mask to transfer the pattern. The resist film is developed to form a resist pattern for the first mask. The hard mask film is etched using the resist pattern of the first mask as a mask, and the pattern of the first mask is transferred to the hard mask film. After removing the resist used for the first mask, a new resist is applied. Similarly, the resist film is sequentially exposed and developed through the second mask, the etching of the hard mask film is repeated, and the pattern of each mask is transferred to the hard mask film. After the pattern through all the masks is transferred to the hard mask film, the processed film is processed by etching or the like using the hard mask film to which all the mask patterns are transferred as a mask.

  When the double patterning process is used as described above, it is possible to form a pattern with a fine pitch, and it is possible to prevent the exposure light of each mask pattern from affecting other mask patterns.

  However, in the double patterning process, misalignment occurs between the patterns of the respective masks due to the overlay accuracy of the exposure machine and the distortion of the wafer. The same applies to the multiple exposure process. In addition, when another film type is formed on the substrate formed by the double patterning process and the pattern is formed using the new third mask, the mask pattern of the several sheets used when forming the double pattern Will be aligned. For this reason, for example, when the exposure is performed by aligning the position with the pattern formed with the first double patterning mask, the positional accuracy (overlapping) between the pattern formed with the second double patterning mask and the third mask pattern is achieved. (Accuracy) is reduced by the amount of misalignment between the first and second masks of double patterning. In order to avoid such misalignment, if the third mask pattern can be exposed in the middle of misalignment between the first mask and the second mask of double patterning, the double patterning can be performed. The overlay accuracy with respect to either the first mask or the second mask can be reduced to half of the misalignment between the first mask and the second mask in double patterning.

  In general, the alignment mark and the overlay measurement mark occupy a large area with respect to the semiconductor element formed on the substrate. Furthermore, when two or more masks are formed for processing a single film to be processed, the number of alignment marks and overlay measurement marks increases twice or more, and these marks occupy a large area. become. In order to solve this problem, a technique has been proposed in which the alignment mark formed in a certain step in the multiple exposure process is erased with another mask.

  Regarding this technique, a method of erasing the alignment mark described in Patent Document 1 will be described below.

  First, a photosensitive first resist film is formed on the surface of the substrate. The first resist film is exposed through the first mask to transfer the first pattern of the first mask. That is, a first latent image mark is formed in which the first pattern includes the first transferred mark and the first transferred mark is transferred to the first resist film. Next, the position information of the substrate is obtained by detecting the first latent image mark, and the second mask and the substrate are aligned based on the position information. The first resist film is exposed through the second mask to transfer the second pattern of the second mask, and the region containing the first latent image mark is exposed to expose the first latent image mark. After erasing, the first resist film is developed.

By performing the steps as described above, the alignment mark of the first mask can be erased.
JP 2003-209049 A

  However, in order to expose the third mask pattern in the middle of the misalignment between the first mask and the second mask of the double patterning, the first mask and the second mask of the second patterning are exposed for each wafer. There is a problem in that the amount of deviation from the mask must be measured separately, and half of the value must be added as an offset during exposure of the third mask pattern, resulting in a significant deterioration in throughput.

  In addition, in order to improve the throughput, when the amount of deviation between the first mask and the second mask of double patterning of a certain wafer is measured, and half the value is added as an offset, another wafer is exposed. Since the amount of deviation between the double patterning first mask and the second mask differs from wafer to wafer, there is a problem that the overlay accuracy with the third mask pattern is lowered by the variation.

  Furthermore, the overlay measurement after the formation of the third mask pattern must also measure the overlay accuracy of both the first mask and the second mask of double patterning, which is more than twice the normal one. There is a problem of requiring measurement time.

  In view of the above-described conventional problems, the present invention exposes a new pattern superimposed on a pattern formed by double patterning, and improves the overlay accuracy when forming a new pattern. The purpose is to shorten the processing time and prevent an increase in alignment marks and overlay measurement marks.

  In order to achieve the above object, the present invention has a configuration in which the alignment mark and the overlay measurement mark are formed using both the first mask and the second mask.

  Specifically, the first alignment mark according to the present invention is formed on a film to be processed using a first mask having a first graphic element and a second mask having a second graphic element. 3 is an alignment mark for aligning the mask 3 and includes a plurality of third graphic elements having the same shape, one side of the third graphic element being formed by the first graphic element, and the like. The side of is formed by the second graphic element.

  According to the first alignment mark, the first mask and the second mask are used so as to include a shift amount between the first mask and the second mask. For this reason, it is possible to improve overlay accuracy when the third mask is aligned using the first alignment mark to form a new pattern. Further, when aligning the third mask, it is not necessary to separately measure the amount of deviation between the first mask and the second mask, so that the processing time for exposure and overlay measurement can be shortened. .

  In the first alignment mark, the first graphic element and the second graphic element are preferably arranged at the same pitch.

  In the first alignment mark, it is preferable that the first graphic element and the second graphic element are arranged at the same pitch and in the same shape.

  If it does in this way, the alignment mark containing the deviation | shift amount of a 1st mask and a 2nd mask can be formed using a 1st mask and a 2nd mask.

  The second alignment mark according to the present invention has a first mask having a first graphic element having the same shape for each row and a second graphic element having the same shape for each row on the film to be processed. An alignment mark formed using the mask of 2 and for alignment of the third mask, comprising a third graphic element in which a plurality of identical shapes are arranged in a matrix, and a third graphic element Is characterized in that the signals are averaged in the column direction.

  According to the second alignment mark, the same shape is arranged in a matrix using the first mask and the second mask having the same shape in the row direction. When aligning the third mask using such a first mask and a second mask and forming a new pattern, the exposure machine averages and processes the signals in the column direction. Since it is detected as an intermediate position of the shift of the second mask with respect to the first mask, the overlay accuracy can be improved. Further, when aligning the third mask, it is not necessary to separately measure the shift amounts of the first mask and the second mask, so that the processing time for exposure and overlay measurement can be shortened. .

  In the second alignment mark, it is preferable that each row of the third graphic element is formed from the first graphic element or the second graphic element.

  In the second alignment mark, the third graphic element is preferably formed by alternately arranging the graphic elements of the first mask and the graphic elements of the second mask.

  In this way, it is possible to form an alignment mark that is detected as an intermediate position corresponding to the displacement of the second mask with respect to the first mask.

  A first alignment mark forming method according to the present invention includes a step (a) of sequentially forming a film to be processed and a hard mask film on a substrate, and forming a first resist pattern on the hard mask film; (B) etching the hard mask film using the first resist pattern as an etching mask, and removing the first resist pattern and then forming a second resist pattern so as to cover a part of the etched hard mask film Step (c) for forming, Step (d) for further etching the hard mask film using the second resist pattern as an etching mask, Step (b) and Step (d) after removing the second resist pattern And a step (e) of etching the film to be processed using the hard mask film etched in step 1 as an etching mask. That.

  According to the first alignment mark forming method, the alignment mark including the shift amount can be formed using the first mask and the second mask. If this alignment mark is used for the alignment of the third mask, a new pattern can be formed without deteriorating both the overlay accuracy and the throughput.

In the first alignment mark forming method, the first resist pattern and the second resist pattern have the same pitch, and patterns having the same shape are arranged, and the step (c) includes the second resist pattern. Preferably, the second resist pattern is formed so as to cover a part of each graphic element formed in the step (b) and not to contact each adjacent graphic element.

  In the first alignment mark forming method, the alignment mark is preferably a pattern composed of third graphic elements having the same pitch and the same shape.

  In this way, it is possible to form an alignment mark that includes the shift amount of the first mask and the second mask.

  The second alignment mark forming method according to the present invention includes a step (a) of sequentially forming a film to be processed and a hard mask film on a substrate, and forming a first resist pattern on the hard mask film; (B) etching the hard mask film using the first resist pattern as an etching mask, and removing the first resist pattern and then forming a second resist pattern so as to cover a part of the etched hard mask film A step (c) of forming, and a step (d) of etching the film to be processed using the etched hard mask film and the second resist pattern as an etching mask.

  According to the second alignment mark forming method, the alignment mark including the shift amount can be formed by using the first mask and the second mask. If this alignment mark is used for the alignment of the third mask, a new pattern can be formed without deteriorating both the overlay accuracy and the throughput.

In the second alignment mark forming method, the first resist pattern and the second resist pattern have the same pitch, and patterns having the same shape are arranged, and the step (c) It is preferable to form the second resist pattern so that the pattern covers a part of each graphic element formed in the step (b) and does not contact each adjacent graphic element.

  In the second alignment mark forming method, the alignment marks are preferably patterns having the same pitch and the same shape.

  In this way, it is possible to form an alignment mark that includes the shift amount of the first mask and the second mask.

  A first overlay measurement mark according to the present invention is formed on a film to be processed using a first mask having a first graphic element and a second mask having a second graphic element, An overlay measurement mark for performing overlay measurement with a mask, comprising a third graphic element, and one side constituting the third graphic element and the other side facing the one side Each is formed from a first graphic element or a second graphic element.

  According to the first overlay measurement mark, the first mask and the second mask are used so as to include a shift amount between the first mask and the second mask. For this reason, since the first overlay measurement mark is detected as an intermediate position of the displacement of the second mask with respect to the first mask, when a new pattern is formed using the third mask, the overlay is overlaid. The alignment accuracy can be improved, and the processing time for exposure and overlay measurement can be shortened.

  The second overlay measurement mark according to the present invention is formed on a film to be processed using a plurality of masks having the same graphic element, has a square shape in plan view, and adjacent graphic elements are different from each other. It is formed from.

  According to the second overlay measurement mark, the overlay measurement mark formed by the first mask and the overlay measurement mark formed by the second mask are formed so as to be alternately arranged. When the measuring instrument detects the signal of the overlay measurement mark, the signal in the column direction is averaged and processed, so that it can be detected as an intermediate position of the shift of the second mask with respect to the first mask.

  The pattern forming method according to the present invention includes a step (a) of applying a resist on a substrate on which a first or second alignment mark is formed, and a step (b) of aligning the substrate using the alignment mark. And a step (c) of exposing the third mask on the substrate after the step (b), and a step (d) of developing the exposed resist. To do.

  According to the pattern formation method, since the first or second alignment mark is used for the alignment of the third mask, a new pattern can be formed without deteriorating both the overlay accuracy and the throughput.

  When the alignment mark and overlay measurement mark according to the present invention are used, double patterning is performed without degrading throughput when a new pattern is exposed by overlaying a pattern formed by double patterning to form a new pattern. Deterioration in overlay accuracy caused by misalignment between the first mask and the second mask is reduced to about half of the misalignment between the first mask and the second mask in double patterning. be able to.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. The first embodiment is an alignment mark and a method for forming the alignment mark. As an example, the alignment mark has 13 line-shaped graphic elements having a short side length of 4 μm and a short pitch of 8 μm in plan view. It is the structure arranged in the side direction.

  FIGS. 1A to 1H show an example of alignment marks according to the first embodiment in the order of forming steps, and FIGS. 1A to 1E show cross-sectional configurations, and FIG. (H) shows the positional relationship between the resist pattern and the alignment mark.

  As shown in FIG. 1A, a processing target film 12 made of a polysilicon film and a hard mask film 13 made of a silicon oxide film are sequentially formed on a semiconductor substrate 11. Next, a resist is applied on the hard mask film 13, and an ordinary lithography process, for example, exposure and development processing using krypton fluoride (KrF) as a light source is performed, and the first mask alignment mark is used. 1 resist pattern 14 is formed. The alignment mark of the first mask has a configuration in which 13 line-shaped graphic elements having a short side length of 6 μm are arranged in the short side direction at a pitch of 8 μm. In the first resist pattern 14, when viewed in plan, the center line in the short side direction of each of the 13 graphic elements has the 13 graphic elements of the alignment mark 15 finally formed on the film 12 to be processed. It is formed so as to be shifted to the right by 1 μm from the position of the center line in the short side direction. That is, when compared with the position of the alignment mark 15 finally formed on the film 12 to be processed, the left side of each of the 13 graphic elements of the first resist pattern 14 is the 13 of the alignment mark 15 in plan view. It coincides with the left side of each graphic element, and the right side of each of the 13 graphic elements of the first resist pattern 14 is formed 2 μm to the right of the right side of each of the 13 graphic elements of the alignment mark 15. This can also be seen from FIG. 1 (f) showing the first resist pattern 14 and FIG. 1 (h) showing the alignment mark 15.

  Next, as shown in FIG. 1B, the hard mask film 13 is dry-etched using the first resist pattern 14 as a mask, and then the first resist pattern 14 is removed. The hard mask film 13a that has been dry-etched is formed with the alignment mark of the first mask, and in comparison with the position of the alignment mark 15 that is finally formed on the film to be processed 12, The left side coincides with the final shape, and the center line in the short side direction of each of the 13 graphic elements is formed at a position shifted by 1 μm to the right.

  Next, as shown in FIG. 1C, a resist is applied again on the hard mask film 13a on which the alignment mark of the first mask is formed, and the alignment mark of the second mask is usually used. The second resist pattern 16 is formed by performing the lithography process. The alignment mark of the second mask has a configuration in which 13 line-shaped graphic elements having a short side length of 6 μm are arranged in the short side direction at a pitch of 8 μm. In the second resist pattern 16, when viewed in plan, the center line in the short side direction of each of the 13 graphic elements has the 13 graphic elements of the alignment mark 15 finally formed on the film 12 to be processed. It is formed so as to be shifted to the left by 1 μm from the position of the center line in the short side direction. That is, as viewed in a plan view, the second resist pattern 16 is formed such that the left and right sides of the first resist pattern 14 are shifted to the opposite side with respect to the finally formed alignment mark 15. Therefore, the right side of each of the 13 graphic elements of the second resist pattern 16 matches the right side of each of the 13 graphic elements of the alignment mark 15, and the left side of each of the 13 graphic elements of the second resist pattern 16 is The alignment mark 15 is formed so as to be located 2 μm left from the left side of each of the 13 graphic elements. This can be seen from FIG. 1G showing the second resist pattern 16 and FIG. 1H showing the alignment mark 15.

  Here, the second resist pattern 16 is formed so as to cover a part of the hard mask film 13 a to which the first resist pattern 15 has been transferred, but the hard pattern not covered by the second resist pattern 16. The mask film 13a is formed so as not to overlap the second resist pattern 16 adjacent thereto.

  Next, as shown in FIG. 1D, the hard mask film 13a is dry-etched using the second resist pattern 16 as a mask, and then the second resist pattern 16 is removed. The hard mask film 13b that has been dry-etched has a left side that coincides with the alignment mark of the first mask and a right side that coincides with the alignment mark of the second mask in plan view, and is finally formed on the film 12 to be processed. The alignment mark 15 is formed in the same shape.

  Next, as shown in FIG. 1E, the film to be processed 12 is dry-etched using the alignment mark of the hard mask film 13b formed using the first resist pattern 14 and the second resist pattern 16 as a mask. Then, the final alignment mark 15 is formed, and the hard mask film 13 is removed.

  As described above, the first mask and the second mask are formed at the same pitch as the alignment mark 15, and each graphic element of the first mask and the second mask has a pitch larger than each graphic element constituting the alignment mark 15. The width of the direction is large, and the center of each graphic element of the first mask and the second mask is separated from the center in the pitch direction of each graphic element constituting the alignment mark 15 by the same distance in the pitch direction across the center. The distance is set to be shorter than ½ of the width in the pitch direction of each line constituting the finally formed alignment mark 15.

  Thus, by performing etching using the first mask and the second mask, the alignment mark 15 can be formed at a desired position on the substrate so as to have a desired dimension. Further, the alignment mark 15 formed in this way is formed with one side in the pitch direction formed by the first mask and the other side formed by the second mask in each graphic element constituting the alignment mark 15. Therefore, even if the second mask is shifted by Δx with respect to the first mask, the center of the alignment mark 15 formed using the first mask and the second mask is Δx. Therefore, the alignment mark 15 is formed at a position where the amount of displacement of the second mask with respect to the first mask is halved.

  As described above, according to the first embodiment, since the alignment mark 15 is formed using the first mask and the second mask, the alignment mark 15 includes a shift amount of both the first mask and the second mask. In other words, if the alignment of the third mask is performed using the alignment mark 15, a new pattern can be formed without deteriorating both the overlay accuracy and the throughput.

  In the first embodiment, the final alignment mark is 13 line-shaped graphic elements. However, the number is not limited to 13 and may be constituted by a plurality. Further, the first mask is shifted to the right and the second mask is shifted to the left with respect to the final alignment mark, but the first mask and the second mask are in the pitch direction. However, it suffices if they are shifted in the left and right directions relative to the final alignment mark. In the first embodiment, the first mask and the second mask have the same configuration, but each graphic element has a different size, and the center position of each graphic element in the pitch direction according to the shape. May be different.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. The second embodiment is an alignment mark and a method for forming the alignment mark. Also in the second embodiment, the alignment mark finally formed will be described as the same configuration as in the first embodiment.

  FIGS. 2A to 2G show an example of alignment marks according to the second embodiment in the order of forming steps, and FIGS. 1A to 1D show cross-sectional configurations, and FIG. -(G) has shown the positional relationship of a resist pattern and an alignment mark.

  As shown in FIG. 2A, a processing target film 22 made of a polysilicon film and a hard mask film 23 made of a silicon oxide film are sequentially formed on a semiconductor substrate 21. Next, a resist is applied on the hard mask film 23, and exposure and development processing using, for example, KrF as a light source is performed as in the first embodiment, so that the first mask having the alignment mark of the first mask is obtained. 1 resist pattern 24 is formed. The alignment mark of the first mask in the second embodiment has a configuration in which 13 line-shaped graphic elements having a short side length of 3 μm are arranged in the short side direction at a pitch of 8 μm. In plan view, the center line in the short side direction of each of the 13 graphic elements in the first resist pattern 24 is the short line of each of the 13 graphic elements of the alignment mark 25 that is finally formed on the film to be processed 22. A first resist pattern is formed so that the position is shifted by 0.5 μm to the left from the position of the center line in the side direction. That is, the left side of each of the 13 graphic elements of the first resist pattern 24 is compared with the left side of each of the 13 graphic elements of the alignment mark 25 as compared with the alignment mark 25 finally formed on the film 22 to be processed. The right sides of the 13 graphic elements of the first resist pattern 24 are formed so as to be located 1 μm to the left of the right sides of the 13 graphic elements of the alignment mark 25. This can be seen from FIG. 2 (e) showing the first resist pattern 24 and FIG. 2 (g) showing the alignment mark 25.

  Next, as shown in FIG. 2B, the hard mask film 23 is dry-etched using the first resist pattern 24 as a mask, and then the first resist pattern 24 is removed. Here, since the hard mask film 23a subjected to dry etching forms the alignment mark of the first mask, compared with the position of the alignment mark 25 finally formed on the film to be processed 22, The left side, which is one side of the long side, coincides with the final shape, and the center line in the short side direction of the 13 line-shaped graphic elements is formed at a position shifted 0.5 μm to the left.

  Next, as shown in FIG. 2C, a resist is applied again on the hard mask film 23a on which the alignment mark of the first mask is formed, and a normal mask is used using the alignment mark of the second mask. A lithography process is performed to form the second resist pattern 26. The alignment mark of the second mask has a configuration in which 13 line-shaped graphic elements having a short side length of 3 μm are arranged in the short side direction at a pitch of 8 μm. In the second resist pattern 26, the center line in the short side direction of each of the 13 graphic elements in the plan view is the position of each of the 13 graphic elements of the alignment mark 25 that is finally formed on the film 22 to be processed. It is formed so as to be shifted to the right by 0.5 μm from the position of the center line in the short side direction. That is, when viewed in plan, the second resist pattern 26 is formed so that the left and right sides of the first resist pattern 24 are shifted to the opposite side with respect to the finally formed alignment mark 25. Accordingly, the right side of each of the 13 graphic elements of the second resist pattern 26 matches the right side of each of the 13 graphic elements of the alignment mark 25, and the left side of each of the 13 graphic elements of the second resist pattern 26 is The alignment mark 25 is formed so as to be located 1 μm to the right of the left side of each of the 13 graphic elements. This can be seen from FIG. 2 (f) showing the second resist pattern 26 and FIG. 2 (g) showing the alignment mark 25.

  Here, the second resist pattern 26 is formed so as to cover a part of the hard mask film 23a to which the first resist pattern 24 has been transferred, but is not covered with the second resist pattern. The film 23a is formed so as not to overlap the second resist pattern 26 adjacent thereto.

  Next, as shown in FIG. 2D, the processed film 22 is dry-etched using the hard mask film 23a to which the first resist pattern is transferred and the second resist pattern 26 as a mask, and the alignment mark 25 is formed. Form. Thereafter, the hard mask film 23a and the second resist pattern 24 are removed. The alignment mark 25 thus formed is formed using the first mask on the left side of each of the 13 graphic elements and the second mask on the right side.

  As described above, the first mask and the second mask are formed at the same pitch as the alignment mark 25, and each graphic element of the first mask and the second mask has a pitch larger than each graphic element constituting the alignment mark 15. The width of the direction is small, and the center of each graphic element of the first mask and the second mask is from the center in the pitch direction of each graphic element constituting the alignment mark 25 in the pitch direction across the center. The distance in the pitch direction is ½ of the difference in length in the pitch direction.

  As described above, by performing etching using the first mask and the second mask as in the first embodiment, the alignment mark 25 is formed at a desired position on the substrate so as to have a desired dimension. Can do. Further, the alignment mark 25 formed in this way is formed with one side in the pitch direction formed by the first mask and the other side formed by the second mask in each graphic element constituting the alignment mark 25. Therefore, even if the second mask is shifted by Δx with respect to the first mask, the center of the alignment mark 25 formed using the first mask and the second mask is Δx. Therefore, the alignment mark 25 is formed at a position where the amount of displacement of the second mask with respect to the first mask is halved.

  As described above, according to the second embodiment, since the alignment mark 25 is formed using the first mask and the second mask, the alignment mark 25 includes a shift amount of both the first mask and the second mask. In other words, if the alignment of the third mask is performed using the alignment mark 25, a new pattern can be formed without deteriorating both the overlay accuracy and the throughput.

  In the second embodiment as well, the final alignment mark is a 13 line-shaped graphic element. However, the final alignment mark is not limited to 13 and may be composed of a plurality of lines. In addition, the final alignment mark is formed on the left side of the first mask and on the right side of the second mask. The first mask and the second mask are formed with respect to the pitch direction. Thus, the left and right sides of the final alignment mark may be formed respectively. In the first embodiment, the first mask and the second mask have the same configuration, but each graphic element has a different size, and the center position of each graphic element in the pitch direction according to the shape. May be different.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. The third embodiment is an alignment mark formed by the same alignment mark forming method as in the first embodiment.

  3A and 3B show the alignment marks of the first and second masks, respectively, and FIG. 3C shows a plan view of the alignment marks formed using the first and second masks. ing.

  As shown in FIG. 3A, the alignment marks 31 of the first mask have four squares each having a side of 4 μm to be the transmitted light portion 32 arranged in one column at a pitch of 16 μm and 13 columns at a pitch of 8 μm in the row direction. It is formed from a mask with a side-by-side configuration. The position of each transmitted light portion 32 is arranged to be the position of the alignment mark that is finally formed.

  As shown in FIG. 3B, the alignment marks 33 of the second mask are such that the transmitted light portions 32 each having a square with a side of 4 μm are arranged in a single row at a pitch of 16 μm, and 13 columns at a pitch of 8 μm in the row direction. It is formed from a mask with a side-by-side configuration. The position of each transmitted light portion 32 is arranged to be the position of the alignment mark that is finally formed.

  Next, as shown in FIG. 3C, the alignment mark 34 formed by the same method as the alignment mark forming method of the first embodiment using the first mask and the second mask is formed on the substrate. In the layer formed above, 13 square holes each having 4 μm sides arranged in a row at 8 μm pitch are arranged in 13 rows at 8 μm pitch. That is, a square of 4 μm on a side is arranged in 7 rows and 13 columns at a pitch of 8 μm. Of the 7 rows, odd rows are formed from the alignment marks 31 of the first mask, and even rows are alignment marks of the second mask. 33. Therefore, the alignment mark 34 is formed including the shift amount of the first mask and the second mask.

  As described above, according to the third embodiment, the alignment mark 34 is formed such that the alignment mark 31 formed by the first mask and the alignment mark 33 formed by the second mask are alternately arranged. This is an alignment mark. When the aligner detects the alignment mark signal, the signal in the column direction is averaged and processed, so that it is detected as an intermediate position of the shift of the second mask with respect to the first mask. Therefore, since the pitch in the row direction is uniform without any variation in the interval for each column, the overlay accuracy is improved.

  As for the alignment mark to be finally formed, a configuration in which squares having a side length of 4 μm are arranged in a 7 × 13 matrix at a pitch of 8 μm may have other shapes instead of the squares. Is not limited to 4 μm, and the pitch width and the number of matrixes are not limited to the example of this embodiment.

  In the third embodiment, FIG. 3 shows an alignment mark for alignment in the X direction. However, as an alignment mark for alignment in the Y direction, the alignment mark shown in FIG. Can be rotated 90 degrees. In that case, the row and the column shall be read each other.

(Fourth embodiment)
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. The fourth embodiment is an alignment mark formed by the same alignment mark forming method as in the first embodiment.

  4 (a) and 4 (b) show alignment marks of the first and second masks, respectively, and FIG. 4 (c) shows a plan view of the alignment marks formed using the first and second masks. ing.

  As shown in FIG. 4 (a), the alignment marks 41 of the first mask are arranged in a row of seven squares each having a side of 4 μm and a square of 6 μm on the side that become the light-shielding portion 42 alternately at a pitch of 8 μm. Within the same row in the row direction, the same square is formed from a mask having a configuration in which 13 columns are arranged at a pitch of 8 μm. Here, the positions of the squares are arranged so as to be the positions of the finally formed alignment marks.

  As shown in FIG. 4B, the alignment marks 43 of the second mask are arranged in a row of seven squares each having a side of 4 μm and a side of 6 μm alternately serving as the light shielding part 42 at a pitch of 8 μm. Within the same row in the row direction, the same square is formed from a mask having a configuration in which 13 columns are arranged at a pitch of 8 μm. Similar to the first mask, the positions of the squares are arranged to be the positions of the alignment marks to be finally formed. However, the 1st mask and the 2nd mask are comprised so that the square whose one side which is the light-shielding part 42 may be 4 micrometers, and the square whose one side is 6 micrometers are opposite.

  Next, as shown in FIG. 4C, the alignment mark 44 formed by the same method as the alignment mark forming method of the first embodiment using the first mask and the second mask is formed on the substrate. A structure in which seven squares each having a side of 4 μm are arranged in one row at an 8 μm pitch are arranged in 13 rows at an 8 μm pitch on the layer formed above. That is, a square with a side of 4 μm is arranged in a 7 × 13 matrix at a pitch of 8 μm. Of the seven rows, odd rows are formed from the alignment marks 41 of the first mask, and even rows are alignment marks 43 of the second mask. Formed from. Therefore, the alignment mark 44 is formed including the shift amount of the first mask and the second mask.

  As described above, according to the fourth embodiment, the alignment mark 44 is formed such that the alignment mark 41 formed by the first mask and the alignment mark 43 formed by the second mask are alternately arranged. This is an alignment mark. When the aligner detects the alignment mark signal, the signal in the column direction is averaged and processed, so that it is detected as an intermediate position of the shift of the second mask with respect to the first mask. Therefore, since the pitch in the row direction is uniform without any variation in the interval for each column, the overlay accuracy is improved.

  As for the alignment mark to be finally formed, a configuration in which squares having a side length of 4 μm are arranged in a 7 × 13 matrix at a pitch of 8 μm may have other shapes instead of the squares. Is not limited to 4 μm, and the pitch width and the number of matrixes are not limited to the example of this embodiment.

  Further, in the fourth embodiment, the alignment mark for performing alignment in the X direction is shown in FIG. 4, but the alignment mark for alignment in the Y direction is shown in FIG. Can be rotated 90 degrees. In that case, the row and the column shall be read each other.

(Fifth embodiment)
Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. The fifth embodiment is an alignment mark formed by the same alignment mark forming method as that of the second embodiment.

  FIGS. 5A and 5B show alignment marks of the first and second masks, respectively, and FIG. 5C shows a plan view of the alignment marks formed using the first and second masks. ing.

  As shown in FIG. 5 (a), the alignment marks 51 of the first mask are arranged in a row of four squares each having a side of 4 μm to form a light-shielding portion 52 at a pitch of 16 μm and 13 rows at a pitch of 8 μm. It is formed from a mask having a different structure. The positions of the squares are arranged to be the positions of the alignment marks that are finally formed.

  As shown in FIG. 5B, the alignment marks 53 of the second mask are arranged in such a way that three squares each having a side of 4 μm to be the light-shielding portion 52 are arranged in one row at a pitch of 16 μm and 13 rows are arranged in a row direction at a pitch of 8 μm. It is formed from a mask having a different structure. Similar to the first mask, the positions of the squares are arranged to be the positions of the alignment marks to be finally formed.

  Next, as shown in FIG. 5C, the alignment mark 54 formed by the same method as the alignment mark forming method of the second embodiment using the first mask and the second mask is formed on the substrate. In the plan view of the layer formed above, 13 squares each having 4 μm sides arranged in a row at 8 μm pitch are arranged in 13 rows at 8 μm pitch. That is, a square having a side of 4 μm is arranged in a 7 × 13 matrix at a pitch of 8 μm. Of the seven rows, odd rows are formed from the alignment marks 51 of the first mask, and even rows are alignment marks 53 of the second mask. Formed from. Therefore, the alignment mark 54 is formed including the shift amount of the first mask and the second mask.

  As described above, according to the fifth embodiment, the alignment mark 54 is formed such that the alignment mark 51 formed by the first mask and the alignment mark 53 formed by the second mask are alternately arranged. This is an alignment mark. When the aligner detects the alignment mark signal, the signal in the column direction is averaged and processed, so that it is detected as an intermediate position of the shift of the second mask with respect to the first mask. Therefore, since the pitch in the row direction is uniform without any variation in the interval for each column, the overlay accuracy is improved.

  As for the alignment mark to be finally formed, a configuration in which squares having a side length of 4 μm are arranged in a 7 × 13 matrix at a pitch of 8 μm may have other shapes instead of the squares. Is not limited to 4 μm, and the pitch width and the number of matrixes are not limited to the example of this embodiment.

  In the fifth embodiment, FIG. 5 shows an alignment mark for alignment in the X direction, but the alignment mark shown in FIG. 5 is used as an alignment mark for alignment in the Y direction. Can be rotated 90 degrees. In that case, the row and the column shall be read each other.

(Sixth embodiment)
Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings. The sixth embodiment is an alignment mark formed by the same alignment mark forming method as that of the second embodiment.

  FIGS. 6A and 6B show alignment marks of the first and second masks, respectively, and FIG. 6C shows a plan view of alignment marks formed using the first and second masks. ing.

  As shown in FIG. 6A, in the alignment mark 61 of the first mask, a square with a side of 4 μm and a square with a side of 6 μm are alternately arranged in a row of 7 at a pitch of 8 μm. In a row direction, the same square is formed from a mask having a configuration in which 13 columns are arranged at a pitch of 8 μm. Here, the positions of the squares are arranged so as to be the positions of the finally formed alignment marks.

  As shown in FIG. 6B, in the alignment marks 63 of the second mask, a square with a side of 4 .mu.m and a square with a side of 6 .mu.m are alternately arranged in a row of 7 at 8 .mu.m pitch. In a row direction, the same square is formed from a mask having a configuration in which 13 columns are arranged at a pitch of 8 μm. Similar to the first mask, the positions of the squares are arranged to be the positions of the alignment marks to be finally formed. However, the first mask and the second mask are configured such that the squares having a side of 4 μm and the squares having a side of 6 μm are opposite to each other, which is the transmitted light portion 62.

  Next, as shown in FIG. 6C, the alignment mark 64 formed by the same method as the alignment mark forming method of the second embodiment using the first mask and the second mask is formed on the substrate. A structure in which seven square holes each having a side of 4 μm are arranged in one row at a pitch of 8 μm on the layer formed above is arranged in 13 rows at a pitch of 8 μm. That is, a square having a side of 4 μm is arranged in a 7 × 13 matrix at a pitch of 8 μm. Of the seven rows, odd rows are formed from the alignment marks 61 of the first mask, and even rows are alignment marks 63 of the second mask. Formed from. Therefore, the alignment mark 64 is formed including the shift amount of the first mask and the second mask.

  As described above, according to the sixth embodiment, the alignment mark 64 is formed such that the alignment mark 61 formed by the first mask and the alignment mark 63 formed by the second mask are alternately arranged. This is an alignment mark. When the aligner detects the alignment mark signal, the signal in the column direction is averaged and processed, so that it is detected as an intermediate position of the shift of the second mask with respect to the first mask. Therefore, since the pitch in the row direction is uniform without any variation in the interval for each column, the overlay accuracy is improved.

  As for the alignment mark to be finally formed, a configuration in which squares having a side length of 4 μm are arranged in a 7 × 13 matrix at a pitch of 8 μm may have other shapes instead of the squares. Is not limited to 4 μm, and the pitch width and the number of matrixes are not limited to the example of this embodiment.

  In the sixth embodiment, FIG. 6 shows an alignment mark for alignment in the X direction. However, as an alignment mark for alignment in the Y direction, the alignment mark shown in FIG. Can be rotated 90 degrees. In that case, the row and the column shall be read each other.

(Seventh embodiment)
The seventh embodiment of the present invention will be described below with reference to the drawings. The seventh embodiment is an overlay measurement mark formed by the same alignment mark forming method as in the first embodiment.

  FIGS. 7A and 7B show overlay measurement marks of the first and second masks, respectively, and FIG. 7C shows overlay measurement marks formed using the first and second masks. A plan view is shown.

  As shown in FIG. 7A, the overlay measurement mark 71 of the first mask is formed from a square mask in which the transmitted light portion 72 has a width of 1 μm and an outer side of 20 μm. Here, the transmitted light portion 72 is disposed so as to be the position of the overlay measurement mark to be finally formed.

  As shown in FIG. 7B, the overlay measurement mark 73 of the second mask is a square mask in which the width of the transmitted light portion 72 is 1 μm and the outer side is 20 μm, and is the same as the first mask. It is formed from a mask in the same shape and position.

  FIG. 7C shows a trench-shaped overlay measurement mark 74 formed by using the first mask and the second mask. The second mask is in the lower right direction with respect to the first mask. It is an overlay measurement mark 74 formed when it is deviated.

  As shown in FIG. 7C, when the overlay measurement mark 74 is formed by shifting the second mask to the lower right with respect to the first mask, each side of the overlay measurement mark 74 is formed. The upper and left sides are formed by the first mask, and the lower and right sides of each side constituting the overlay measurement mark 74 are formed by the second mask.

  As described above, according to the seventh embodiment, like the alignment mark of the first embodiment, the overlay measurement mark 74 is formed including the shift amount of the first mask and the second mask, and This is detected as an intermediate position of the second mask with respect to the mask.

  Note that the shape of the overlay measurement mark was formed using the first and second masks having the same shape and the same position, the transmitted light portion having a width of 1 μm and an outer side of 20 μm. Without being limited to the shape, when the first mask and the second mask are deviated from each other, a part of the first mask and the second mask may be overlapped to form an overlay measurement mark.

(Eighth embodiment)
Hereinafter, an eighth embodiment of the present invention will be described with reference to the drawings. The eighth embodiment is an overlay measurement mark formed by the same alignment mark forming method as in the first embodiment.

  FIGS. 8A and 8B show overlay measurement marks for the first and second masks, respectively, and FIG. 8C shows overlay measurement marks formed using the first and second masks. A plan view is shown.

  As shown in FIG. 8A, the overlay measurement mark 81 of the first mask is formed from a square mask in which the transmitted light portion 82 has a width of 1 μm and an outer side of 20 μm. Here, the transmitted light portion 82 is disposed so as to be the position of the overlay measurement mark to be finally formed.

  As shown in FIG. 8B, the overlay measurement mark 83 of the second mask is formed from a square mask in which the transmitted light portion 82 has a width of 1 μm and an outer side of 19.5 μm. Here, the transmitted light portion 82 of the second mask is arranged so as to be the position of the overlay measurement mark that is finally formed in the same manner as the first mask.

  FIG. 8C shows a trench-shaped overlay measurement mark 84 formed by using the first mask and the second mask. The second mask is in the lower right direction with respect to the first mask. It is the overlay measurement mark 84 formed when it is shifted to. If the overlay measurement mark 84 is formed without misalignment between the first mask and the second mask, the overlay measurement mark 84 shown in FIG. 8C has an equal side of 1.25 μm on each side. The outer side of the trench having a width formed in the film to be processed should be formed from the first mask and the inner side should be formed from the second mask.

  As shown in FIG. 8C, when the overlay measurement mark 84 is formed by shifting the second mask to the lower right with respect to the first mask, each side of the overlay measurement mark 84 is formed. Of these, the outer side is formed by the first mask, and the inner side is formed by the second mask.

  As described above, according to the eighth embodiment, like the alignment mark of the first embodiment, the overlay measurement mark 84 is formed including the shift amount of the first mask and the second mask, This is detected as an intermediate position of the second mask with respect to the mask. Furthermore, since the overlay measurement mark 84 has a rectangular shape, it is possible to improve the position detection accuracy and measurement accuracy of the overlay measurement mark 84 by the measurement device.

  Note that the shape of the mask constituting the overlay measurement mark is not limited to the first and second masks of the eighth embodiment. Any shape that overlaps a part of the first mask and the second mask to form an overlay measurement mark when the first mask and the second mask are shifted may be used.

(Ninth embodiment)
The ninth embodiment will be described below with reference to the drawings. The ninth embodiment is an overlay measurement mark formed by the same alignment mark forming method as that of the first embodiment.

  FIGS. 9A and 9B show overlay measurement marks of the first and second masks, respectively, and FIG. 9C shows overlay measurement marks formed using the first and second masks. A plan view is shown.

  As shown in FIG. 9A, the overlay measurement mark 91 of the first mask is formed from a square mask in which the width of the light shielding portion 92 is 1 μm and the outer side is 20 μm. Here, the light shielding portion 92 is arranged so as to be the position of the overlay measurement mark to be finally formed.

  As shown in FIG. 9B, the overlay measurement mark 93 of the second mask is formed from a square mask in which the width of the light shielding portion 92 is 1 μm and the outer side is 19.5 μm. Here, the light-shielding portion 92 of the second mask is disposed so as to be the position of the overlay measurement mark that is finally formed in the same manner as the first mask.

  FIG. 9C shows a ridge-shaped overlay measurement mark 94 formed by using the first mask and the second mask. The second mask is in the lower right direction with respect to the first mask. It is the overlay measurement mark 94 formed when it is shifted to. If the overlay measurement mark 94 is formed without misalignment between the first mask and the second mask, the overlay measurement mark 94 shown in FIG. From one mask, the outer sides should be formed so that each side formed from the second mask has an equal width of 0.75 μm.

  As shown in FIG. 9C, when the overlay measurement mark 94 is formed by shifting the second mask to the lower right with respect to the first mask, each side of the overlay measurement mark 94 is formed. Of these, the inner side is formed by the first mask, and the outer side is formed by the second mask.

  Thus, according to the ninth embodiment, like the alignment mark of the first embodiment, the overlay measurement mark 94 is formed including the amount of displacement between the first mask and the second mask, This is detected as an intermediate position of the second mask with respect to the mask. Furthermore, since the overlay measurement mark 94 formed from the first mask and the second mask has a quadrangular shape, the position detection accuracy and measurement accuracy of the overlay measurement mark 94 by the measurement device can be improved.

  Note that the shape of the mask constituting the overlay measurement mark is not limited to the first and second masks of the ninth embodiment. Any shape that overlaps a part of the first mask and the second mask to form an overlay measurement mark when the first mask and the second mask are shifted may be used.

(Tenth embodiment)
The tenth embodiment will be described below with reference to the drawings. The tenth embodiment is an overlay measurement mark formed by the same alignment mark forming method as that of the first embodiment.

  FIGS. 10A and 10B show overlay measurement marks of the first and second masks, respectively, and FIG. 10C shows overlay measurement marks formed using the first and second masks. A plan view is shown.

  As shown in FIG. 10A, the overlay measurement mark 101 of the first mask is formed from a square mask in which the width of the light shielding portion 102 is 1 μm and the outer side is 20 μm. Here, the light shielding portion 102 is arranged so as to be the position of the overlay measurement mark to be finally formed.

  As shown in FIG. 10B, the overlay measurement mark 103 of the second mask is a square mask in which the width of the light shielding portion 102 is 1 μm and the outer side is 20 μm, and has the same shape as the first mask. And it is formed from the mask of the same position.

  FIG. 10C shows a ridge-shaped overlay measurement mark 104 formed by using the first mask and the second mask. The second mask is in the lower right direction with respect to the first mask. This is the overlay measurement mark 104 that is formed when it is shifted to.

  As shown in FIG. 10C, when the overlay measurement mark 104 is formed by shifting the second mask to the lower right with respect to the first mask, each side of the overlay measurement mark 104 is formed. The upper and left sides are formed by the first mask, and the lower and right sides of each side constituting the overlay measurement mark 104 are formed by the second mask.

  As described above, according to the tenth embodiment, like the alignment mark of the first embodiment, the overlay measurement mark 104 is formed including the shift amount of the first mask and the second mask. This is detected as an intermediate position of the second mask with respect to the mask.

  Note that the shape of the overlay measurement mark is the same shape and is formed using the first and second masks having the light-shielding portion that is a square having the width of 1 μm and the outer side of 20 μm at the same position. Without being limited to the above, when the first mask and the second mask are shifted from each other, the overlapping measurement marks may be formed by partially overlapping the first mask and the second mask.

(Eleventh embodiment)
The eleventh embodiment of the present invention will be described below with reference to the drawings. The eleventh embodiment is an overlay measurement mark formed by the same alignment mark forming method as the second embodiment.

  FIGS. 11A and 11B show overlay measurement marks of the first and second masks, respectively, and FIG. 11C shows overlay measurement marks formed using the first and second masks. A plan view is shown.

  As shown in FIG. 11A, the overlay measurement mark 111 of the first mask is formed from a square mask in which the light shielding portion 112 has a width of 1 μm and an outer side of 20 μm. Here, the light shielding portion 112 is disposed so as to be the position of the overlay measurement mark to be finally formed.

  As shown in FIG. 11B, the overlay measurement mark 113 of the second mask is a square mask in which the width of the light shielding portion 112 is 1 μm and the outer side is 20 μm, and has the same shape as the first mask. And it is formed from the mask of the same position.

  FIG. 11C shows a ridge-shaped overlay measurement mark 114 formed by using the first mask and the second mask. The second mask is in the lower right direction with respect to the first mask. It is an overlay measurement mark 114 formed when it is deviated.

  As shown in FIG. 11C, when the overlay measurement mark 114 is formed by shifting the second mask to the lower right with respect to the first mask, each side constituting the overlay measurement mark 114 is formed. The upper and left sides are formed by the first mask, and the lower and right sides of each side constituting the overlay measurement mark 114 are formed by the second mask.

  As described above, according to the eleventh embodiment, like the alignment mark of the second embodiment, the overlay measurement mark 114 is formed including the shift amount of the first mask and the second mask, This is detected as an intermediate position of the second mask with respect to the mask.

  Note that the shape of the overlay measurement mark is the same shape and is formed using the first and second masks having the light-shielding portion that is a square having the width of 1 μm and the outer side of 20 μm at the same position. Without being limited to the above, when the first mask and the second mask are shifted from each other, the overlapping measurement marks may be formed by partially overlapping the first mask and the second mask.

(Twelfth embodiment)
The twelfth embodiment will be described below with reference to the drawings. The twelfth embodiment is an overlay measurement mark formed by the same alignment mark forming method as that of the second embodiment.

  FIGS. 12A and 12B show overlay measurement marks for the first and second masks, respectively, and FIG. 12C shows overlay measurement marks formed using the first and second masks. A plan view is shown.

  As shown in FIG. 12A, the overlay measurement mark 121 of the first mask is formed from a square mask in which the width of the light shielding portion 122 is 1 μm and the outer side is 20 μm. Here, the light shielding part 122 is arranged so as to be the position of the overlay measurement mark to be finally formed.

  As shown in FIG. 12B, the overlay measurement mark 123 of the second mask is formed from a square mask in which the width of the light shielding portion 122 is 1 μm and the outer side is 19.5 μm. Here, the light-shielding portion 122 of the second mask is arranged so as to be the position of the overlay measurement mark that is finally formed in the same manner as the first mask.

  FIG. 12C shows a ridge-shaped overlay measurement mark 124 formed by using the first mask and the second mask. The second mask is in the lower right direction with respect to the first mask. It is the overlay measurement mark 124 formed when it is shifted to. If the overlay measurement mark 124 is formed without misalignment between the first mask and the second mask, the overlay measurement mark 124 shown in FIG. From one mask, the inner side should be formed from the second mask and each side should be formed with an equal width of 1.25 μm.

  As shown in FIG. 12C, when the overlay measurement mark 124 is formed by shifting the second mask to the lower right with respect to the first mask, each side of the overlay measurement mark 124 is formed. Of these, the outer side is formed by the first mask, and the inner side is formed by the second mask.

  As described above, according to the twelfth embodiment, like the alignment mark of the second embodiment, the overlay measurement mark 124 is formed including the shift amount of the first mask and the second mask, This is detected as an intermediate position of the second mask with respect to the mask. Furthermore, since the overlay measurement mark 124 formed from the first mask and the second mask has a quadrangular shape, the position detection accuracy and measurement accuracy of the overlay measurement mark 124 by the measurement device can be improved.

  Note that the shape of the mask constituting the overlay measurement mark is not limited to the first and second masks of the twelfth embodiment. Any shape that overlaps a part of the first mask and the second mask to form an overlay measurement mark when the first mask and the second mask are shifted may be used.

(13th Embodiment)
The thirteenth embodiment of the present invention will be described below with reference to the drawings. The thirteenth embodiment is an overlay measurement mark formed by the same alignment mark forming method as that of the second embodiment.

  FIGS. 13A and 13B show overlay measurement marks for the first and second masks, respectively, and FIG. 13C shows overlay measurement marks formed using the first and second masks. A plan view is shown.

  As shown in FIG. 13A, the overlay measurement mark 131 of the first mask is formed from a square mask in which the transmitted light portion 132 has a width of 1 μm and an outer side of 20 μm. Here, the transmitted light portion 132 is disposed so as to be the position of the overlay measurement mark to be finally formed.

  As shown in FIG. 13B, the overlay measurement mark 133 of the second mask is formed from a square mask in which the transmitted light portion 132 has a width of 1 μm and an outer side of 19.5 μm. Here, the transmitted light portion 132 of the second mask is arranged so as to be the position of the overlay measurement mark that is finally formed in the same manner as the first mask.

  FIG. 13C shows a trench-shaped overlay measurement mark 134 formed by using the first mask and the second mask. The second mask is in the lower right direction with respect to the first mask. It is the overlay measurement mark 134 formed when it is shifted to. If the overlay measurement mark 134 is formed without displacement between the first mask and the second mask, the overlay measurement mark 134 shown in FIG. From one mask, an equal trench should be formed with the width of each side having an outer side formed from the second mask of 0.75 μm.

  As shown in FIG. 13C, when the overlay measurement mark 134 is formed by shifting the second mask to the lower right with respect to the first mask, each side constituting the overlay measurement mark 134 is formed. Of these, the inner side is formed by the first mask, and the outer side is formed by the second mask.

  Thus, according to the thirteenth embodiment, like the alignment mark of the second embodiment, the overlay measurement mark 134 is formed including the amount of displacement between the first mask and the second mask, This is detected as an intermediate position of the second mask with respect to the mask. Furthermore, since the overlay measurement mark 134 formed from the first mask and the second mask has a quadrangular shape, the position detection accuracy and measurement accuracy of the overlay measurement mark 134 by the measurement device can be improved.

  Note that the shape of the mask constituting the overlay measurement mark is not limited to the first and second masks of the thirteenth embodiment. Any shape that overlaps a part of the first mask and the second mask to form an overlay measurement mark when the first mask and the second mask are shifted may be used.

(Fourteenth embodiment)
The fourteenth embodiment of the present invention will be described below with reference to the drawings. The fourteenth embodiment is an overlay measurement mark formed by the same alignment mark forming method as in the second embodiment.

  FIGS. 14A and 14B show overlay measurement marks of the first and second masks, respectively, and FIG. 14C shows overlay measurement marks formed using the first and second masks. A plan view is shown.

  As shown in FIG. 14A, the overlay measurement mark 141 of the first mask is formed from a square mask in which the transmitted light portion 142 has a width of 1 μm and an outer side of 20 μm. Here, the transmitted light portion 142 is arranged so as to be the position of the overlay measurement mark to be finally formed.

  As shown in FIG. 14B, the overlay measurement mark 143 of the second mask is a square mask in which the transmitted light portion 142 has a width of 1 μm and an outer side of 20 μm, and is the same as the first mask. It is formed from a mask in the same shape and position.

  FIG. 14C shows a trench-shaped overlay measurement mark 144 formed by using the first mask and the second mask. The second mask is in the lower right direction with respect to the first mask. It is an overlay measurement mark 144 formed when it is shifted to.

  As shown in FIG. 14C, when the overlay measurement mark 144 is formed by shifting the second mask to the lower right with respect to the first mask, each side constituting the overlay measurement mark 144 is formed. The lower and right sides are formed by the first mask, and the upper and left sides of each side constituting the overlay measurement mark 144 are formed by the second mask.

  As described above, according to the fourteenth embodiment, like the alignment mark of the first embodiment, the overlay measurement mark 144 is formed including the amount of displacement between the first mask and the second mask. This is detected as an intermediate position of the second mask with respect to the mask.

  Note that the shape of the overlay measurement mark was formed using the first and second masks having the same shape and the same position, the transmitted light portion having a width of 1 μm and an outer side of 20 μm. Without being limited to the shape, when the first mask and the second mask are deviated from each other, a part of the first mask and the second mask may be overlapped to form an overlay measurement mark.

(Fifteenth embodiment)
The fifteenth embodiment of the present invention will be described below with reference to the drawings. The fifteenth embodiment is an overlay measurement mark formed by the same alignment mark forming method as the first embodiment.

  FIGS. 15A and 15B show overlay measurement marks for the first and second masks, respectively, and FIG. 15C shows overlay measurement marks formed using the first and second masks. A plan view is shown.

  As shown in FIG. 15A, the overlay measurement mark 151 of the first mask is configured so that squares having a side of 1 μm that form the transmitted light portion 152 form a square frame of 16 μm at a pitch of 4 μm. Formed from the mask. The 16 transmitted light portions 152 constituting the first mask are arranged in 5 vertical and horizontal directions so that the 16 transmitted light portions of the first mask and the position of the overlay measurement mark to be finally formed are located. Is arranged.

  As shown in FIG. 15B, the overlay measurement mark 153 of the second mask has a square frame of 16 μm with a pitch of 4 μm and a transmitted light portion 152 having a square of 1 μm on one side, like the first mask. It is formed from a mask that is arranged side by side so as to be formed, and is arranged from four vertically and horizontally, and is formed from a mask that is configured not to overlap the transmitted light portion 152 of the first mask. Here, the transmitted light portion 152 of the second mask is arranged so as to be the position of the overlay measurement mark that is finally formed in the same manner as the first mask.

  FIG. 15C shows an overlay measurement mark 154 formed using the first mask and the second mask. The overlay measurement mark 154 has a configuration in which squares having a side of 1 μm are arranged so as to form a square frame having a pitch of 2 μm and a side of 16 μm, and the square formed by the first mask has a side of 1 μm and the second. In this configuration, squares each having a side of 1 μm formed from a mask are alternately arranged. Therefore, the overlay measurement mark 154 is formed including the shift amount of the first mask and the second mask.

  As described above, according to the fifteenth embodiment, the overlay measurement mark 154 includes the overlay measurement mark 151 formed by the first mask and the overlay measurement mark 153 formed by the second mask alternately. Since they are formed side by side, when the overlay measuring instrument detects the signal of the overlay measurement mark, the signals in the column direction are averaged and processed, so that the shift amount of the second mask relative to the first mask is processed. It is detected as an intermediate position.

  Note that the shape of the mask constituting the overlay measurement mark is not limited to the first and second masks of the fifteenth embodiment. What is necessary is just the structure comprised from the 1st mask and the 2nd mask, and forming so that the shift | offset | difference amount of a 1st mask and a 2nd mask may be included.

(Sixteenth embodiment)
The sixteenth embodiment of the present invention will be described below.

  After the alignment mark of the first embodiment and the overlay measurement mark of the seventh embodiment are formed, a resist is applied, and alignment and exposure of the third mask are performed using the alignment mark. 3 and the first and second masks are measured in the horizontal direction (x) and the vertical direction (y), and are shown as overlay values.

  The overlay values of the first mask and the third mask are X: 3.3 nm and Y: 4.8 nm, and the overlay values of the second mask and the third mask are X: -2. .6 nm, Y: -3.5 nm. From this value, it can be seen that the shift amount of the third mask is X: 0.35 nm and Y: 0.65 nm with respect to the middle between the first mask and the second mask.

  Further, on the same substrate, the overlay value was measured when the alignment and exposure of the third mask were performed using the alignment marks of the first mask.

  The overlay values of the first mask and the third mask are X: 2.3 nm and Y: 3.4 nm, and the overlay values of the second mask and the third mask are X: -3. 0.7 nm, Y: −5.5 nm. As described above, when alignment is performed only with the alignment mark of the first mask, the overlay value with the first mask is small, but the overlay value with the second mask is large.

  In addition, the overlay value with the third mask was measured using the overlay measurement mark of the seventh embodiment. As a result, the overlay values are X: 0.35 nm, Y: 0.65 nm, and the deviation amount between the third mask and the overlay measurement mark is the third mask, the first mask, and the second mask. The overlay measurement mark formed from the first mask and the second mask coincides with the amount of deviation from the position of the middle of the mask, and includes the amount of deviation between the first mask and the second mask. I understand that

  According to the sixteenth embodiment, when a pattern is formed by overlapping the third mask using the alignment mark of the first embodiment, the alignment mark of the first embodiment is a second mask relative to the first mask. Therefore, the third mask pattern can be accurately formed at a substantially intermediate position between the first mask and the second mask. In addition, the overlay measurement with the third mask using the overlay measurement mark of the seventh embodiment is equivalent to the amount of deviation of the second mask from the first mask by the overlay measurement mark of the seventh embodiment. Since it is formed at an intermediate position, overlay measurement of the third mask pattern and an approximately intermediate position between the first mask and the second mask can be performed with high accuracy.

  In the present invention, KrF is used as the light source for exposure. However, the light source is not limited to this, and ultraviolet rays, X-rays, charged beams, particularly G-rays (436 nm), i-rays having a wavelength of 450 nm or less. (365 nm), KrF excimer laser (248 nm), argon fluoride (ArF) excimer laser (193 nm), electron beam, X-ray, vacuum ultraviolet (VUV) light, or extreme ultraviolet (EUV) light.

  Further, although a polysilicon film is exemplified as the film to be processed and a silicon oxide film is exemplified as the hard mask film, the present invention is not limited to these.

  According to the alignment mark and the method for forming the alignment mark according to the present invention, when a new pattern is superimposed on a pattern formed by double patterning and exposed to form a new pattern, the double patterning is performed without degrading the throughput. The overlay accuracy caused by the misalignment between the first mask and the second mask can be reduced to about half of the misalignment between the first mask and the second mask. This is useful for an alignment mark for forming a pattern, a method for forming the alignment mark, and the like.

It is sectional drawing and the top view which show the formation process of the alignment mark which concerns on the 1st Embodiment of this invention. It is sectional drawing and the top view which show the formation process of the alignment mark which concerns on the 2nd Embodiment of this invention. It is a top view of the alignment mark formed using the alignment mark of the 1st and 2nd mask and the 1st and 2nd mask which concern on the 3rd Embodiment of this invention. It is a top view of the alignment mark formed using the alignment mark of the 1st and 2nd mask and the 1st and 2nd mask which concern on the 4th Embodiment of this invention. It is a top view of the alignment mark formed using the alignment mark of the 1st and 2nd mask and the 1st and 2nd mask which concern on the 5th Embodiment of this invention. It is a top view of the alignment mark formed using the alignment mark of the 1st and 2nd mask and the 1st and 2nd mask which concern on the 6th Embodiment of this invention. It is a top view of the overlay measurement mark formed using the overlay measurement mark of the 1st and 2nd mask and the 1st and 2nd mask according to the seventh embodiment of the present invention. It is a top view of the overlay measurement mark formed using the overlay measurement mark of the 1st and 2nd mask and the 1st and 2nd mask according to the eighth embodiment of the present invention. It is a top view of the overlay measurement mark formed using the overlay measurement mark of the 1st and 2nd mask and the 1st and 2nd mask according to the ninth embodiment of the present invention. It is a top view of the overlay measurement mark formed using the overlay measurement mark of the 1st and 2nd mask and the 1st and 2nd mask according to the tenth embodiment of the present invention. It is a top view of the overlay measurement mark formed using the overlay measurement mark of the 1st and 2nd mask and the 1st and 2nd mask according to the eleventh embodiment of the present invention. It is a top view of the overlay measurement mark formed using the overlay measurement mark of the 1st and 2nd mask and the 1st and 2nd mask according to the twelfth embodiment of the present invention. It is a top view of the overlay measurement mark formed using the overlay measurement mark of the 1st and 2nd mask and the 1st and 2nd mask according to the thirteenth embodiment of the present invention. It is a top view of the overlay measurement mark formed using the overlay measurement mark of the 1st and 2nd mask and the 1st and 2nd mask according to the fourteenth embodiment of the present invention. It is a top view of the overlay measurement mark formed using the overlay measurement mark of the 1st and 2nd mask and the 1st and 2nd mask according to the fifteenth embodiment of the present invention.

Explanation of symbols

11 Semiconductor substrate 12 Processed film 13 Hard mask film 13a Hard mask film 13b Hard mask film 14 First resist pattern 15 Alignment mark 16 Second resist pattern 21 Semiconductor substrate 22 Processed film 23 Hard mask film 23a Hard mask film 24 First resist pattern 25 Alignment mark 26 Second resist pattern 31 Alignment mark 32 Transmitted light portion 33 Alignment mark 34 Alignment mark 41 Alignment mark 42 Shielding portion 43 Alignment mark 44 Alignment mark 51 Alignment mark 52 Shielding portion 53 Alignment mark 54 Alignment Mark 61 Alignment mark 62 Transmitted light portion 63 Alignment mark 64 Alignment mark 71 Overlay measurement mark 72 Transmitted light portion 73 Overlay measurement mark 74 Overlay measurement mark 81 Overlay measurement mark 82 Transmitted light portion 83 Overlay measurement mark 84 Overlay measurement mark 91 Overlay measurement mark 92 Light blocking portion 93 Overlay measurement mark 94 Overlay measurement mark 101 Overlay measurement Mark 102 Light shielding portion 103 Overlay measurement mark 104 Overlay measurement mark 111 Overlay measurement mark 112 Light shielding portion 113 Overlay measurement mark 114 Overlay measurement mark 121 Overlay measurement mark 122 Light shielding portion 123 Overlay measurement mark 124 Overlay measurement mark 131 Overlay measurement mark 132 Transmitted light portion 133 Overlay measurement mark 134 Overlay measurement mark 141 Overlay measurement mark 142 Transmitted light portion 143 Overlay measurement mark 144 Combined measuring mark 151 overlay measuring mark 152 transmitting light 153 overlay measuring mark 154 overlay measurement mark

Claims (15)

  An alignment mark formed on a film to be processed using a first mask having a first graphic element and a second mask having a second graphic element, and for aligning the third mask. A plurality of third graphic elements having the same shape, wherein one side of the third graphic element is formed by the first graphic element, and the other side is formed by the second graphic element. An alignment mark characterized by   The alignment mark according to claim 1, wherein the first graphic element and the second graphic element are arranged at the same pitch.   The alignment mark according to claim 1, wherein the first graphic element and the second graphic element are arranged at the same pitch and in the same shape.   A film to be processed is formed using a first mask having a first graphic element having the same shape for each row and a second mask having a second graphic element having the same shape for each row. Alignment mark for aligning the mask of FIG. 5, comprising a third graphic element in which a plurality of identical shapes are arranged in a matrix, and signals are averaged in the column direction in the third graphic element An alignment mark characterized by that.   The alignment mark according to claim 4, wherein each row of the third graphic element is formed from the first graphic element or the second graphic element.   6. The alignment mark according to claim 5, wherein the third graphic element is formed by alternately arranging the graphic elements of the first mask and the graphic elements of the second mask. A step (a) of sequentially forming a film to be processed and a hard mask film on a substrate and forming a first resist pattern on the hard mask film;
Etching the hard mask film using the first resist pattern as an etching mask (b);
(C) forming a second resist pattern so as to cover a part of the etched hard mask film after removing the first resist pattern;
A step (d) of further etching the hard mask film using the second resist pattern as an etching mask;
And (e) etching the film to be processed using the hard mask film etched in the steps (b) and (d) as an etching mask after removing the second resist pattern. An alignment mark forming method characterized by the above. The first resist pattern and the second resist pattern have the same pitch, and patterns having the same shape are arranged,
In the step (c), the second resist pattern covers a part of the graphic elements formed in the step (b) and does not contact the adjacent graphic elements. 8. The method of forming an alignment mark according to claim 7, wherein a pattern is formed.   9. The method of forming an alignment mark according to claim 7, wherein the alignment mark is a pattern composed of third graphic elements having the same pitch and the same shape. A step (a) of sequentially forming a film to be processed and a hard mask film on a substrate and forming a first resist pattern on the hard mask film;
Etching the hard mask film using the first resist pattern as an etching mask (b);
(C) forming a second resist pattern so as to cover a part of the etched hard mask film after removing the first resist pattern;
And a step (d) of etching the film to be processed using the etched hard mask film and the second resist pattern as an etching mask. The first resist pattern and the second resist pattern have the same pitch, and patterns having the same shape are arranged, respectively.
In the step (c), the second resist pattern covers a part of the graphic elements formed in the step (b) and does not contact the adjacent graphic elements. The method of forming an alignment mark according to claim 10, wherein a pattern is formed.   12. The method of forming an alignment mark according to claim 10, wherein the alignment mark is a pattern composed of third graphic elements having the same pitch and the same shape.   Overlay measurement for performing overlay measurement with a third mask formed on a film to be processed using a first mask having a first graphic element and a second mask having a second graphic element A first graphic element comprising a third graphic element, wherein one side constituting the third graphic element and the other side opposite to the one side are the first graphic element or the second graphic element, respectively. An overlay measurement mark formed from a graphic element.   Overlapping characterized in that it is formed using a plurality of masks having the same graphic element on a film to be processed, is rectangular in plan view, and adjacent graphic elements are formed from different masks Measurement mark. A step (a) of applying a resist on the substrate on which the alignment mark according to claim 1 or 4 is formed;
(B) performing alignment of the substrate using the alignment mark;
A step (c) of exposing the third mask on the substrate after the step (b);
And a step (d) of developing the exposed resist.

Images