JPH0820231B2 - Mask pattern inspection method - Google Patents

Description

The present invention relates to a mask pattern inspection method, and more particularly to a mask pattern inspection method created by two or more design rules according to the functional content of a semiconductor element and the like. Without processing
For the purpose of shortening the inspection time of the mask pattern and improving the processing efficiency of the inspection apparatus, the first mask pattern is formed in the first pattern area in the first plane according to the first design standard. In the second pattern area, a second mask pattern larger than the first mask pattern is different from the first design standard in the second pattern area.
A method for inspecting a defect of an inspection object formed according to the first design standard, wherein a defect inspection standard for a first pattern region is created in accordance with the first design standard, and the second pattern is prepared in accordance with the second design standard. A defect inspection standard for the second pattern region is created, an inspection image is acquired for each of the first pattern region and the second pattern region corresponding to the defect inspection standard, and the inspection image for the first pattern region is acquired. And the defect inspection standard created by the first design standard, the defect inspection of the first mask pattern is performed, and the inspection image of the second pattern region and the defect inspection created by the second design standard. It is configured to include a defect inspection of the second mask pattern as compared with a reference.

[Industrial applications]

The present invention relates to a mask pattern inspection method, and more particularly to a mask pattern inspection method created by two or more design rules according to the functional content of a semiconductor element.

In recent years, with the ultra-miniaturization and high functionality of semiconductor integrated circuit devices, one mask pattern includes many mask pattern regions created by two or more design pattern standards.

By the way, the defect detection of the mask pattern created by the different design pattern reference is performed by changing the defect detection reference and repeatedly inspecting the entire surface of the mask pattern many times. Therefore, as a result of inspecting the mask pattern area with a defect detection standard that does not match the mask pattern area, it is necessary to perform a process of determining a pseudo defect that is determined to be a defect, which requires a lot of inspection time and the like. There is a problem that the throughput of the device is reduced.

Therefore, there is a demand for an inspection method capable of inspecting a mask pattern efficiently in a short time.

[Conventional technology]

8 (a) and 8 (b) are explanatory views related to the mask pattern inspection method of the conventional example.

FIG. 3A shows a diagram relating to a mask pattern of a semiconductor integrated circuit device.

In the figure, the mask pattern 1 includes, for example, mask pattern areas A1 to
Composed of A3.

The mask pattern area A1 is, for example, a formation area of a pad electrode or the like provided on the outer peripheral portion of the semiconductor integrated circuit device, and the defect detection reference is ε1. Similarly, the mask pattern area A2 is a selection gate transistor formation area or the like,
The defect detection criterion is ε2. Also, the mask pattern area
A3 is a memory element formation region, etc., and the defect detection criterion is ε
It is 3. Regarding the defect detection criteria at this time, ε1> ε
2> ε3.

FIG. 2B shows a flowchart of the mask pattern inspection method.

In the figure, first, in step P1, the mask pattern area A1
˜A3, the entire surface of the mask pattern 1 is inspected based on the defect detection reference ε1. At this time, a true defect in the mask pattern area A1 is detected, and the mask pattern areas A2 and A3 are detected as pseudo defects.

Next, in step P2, the entire surface of the mask pattern 1 is inspected similarly based on the defect detection reference ε2. On this occasion,
While the true defect of the mask pattern area A2 is detected,
The mask pattern area A3 is detected as a pseudo defect.

Furthermore, in step P3, based on the defect detection criterion ε3,
Inspect the entire surface of the mask pattern.

Then, in step P4, the selection of the pseudo defect is determined. At this time, with respect to the mask pattern area A1, the pseudo defects of the mask pattern areas A2 and A3 are removed, and similarly, with respect to the mask pattern area A2, the pseudo defects of the mask pattern area A3 are removed, and the mask pattern areas A1 to A3 are removed from the mask pattern areas A1 to A3. Defects have been found.

[Problems to be Solved by the Invention]

Therefore, with respect to one mask pattern 1, the entire surface inspection of the mask pattern is repeated every time the defect detection criteria ε1, ε2, ε3 change.

Therefore, when the design pattern standards R1, R2, R3 ... And the defect detection standards ε1, ε2, ε3 ... Increase for the high integration and high density of the semiconductor integrated circuit device, the entire mask pattern is covered. The number of inspections also increases. Further, the increase in the number of inspections increases the inspection time and the pseudo defect determination processing.

As a result, the inspection time for one mask pattern becomes long, the throughput of the inspection device is reduced, and there is a problem that an efficient inspection cannot be performed.

The present invention has been made in view of the problems of the conventional example, and aims at shortening the mask pattern inspection time and improving the processing efficiency of the inspection apparatus by eliminating the process of discriminating the pseudo defect of the mask pattern. An object of the present invention is to provide a mask pattern inspection method that enables the above.

[Means for solving the problem]

FIGS. 1 (a) and 1 (b) show a principle diagram relating to the mask pattern inspection method of the present invention.

In the method, the first mask pattern is created in the first pattern area according to the first design standard in the same plane, and the second mask area is larger than the first mask pattern in the second pattern area. Is a method for inspecting a defect of an object to be inspected, the mask pattern of which is formed by a second design standard different from the first design standard, and the defect of the first pattern region according to the first design standard. An inspection standard is created, a defect inspection standard for the second pattern region is created in accordance with the second design standard, and inspection is performed for each of the first pattern region and the second pattern region corresponding to the defect inspection standard. The first image is acquired by comparing the inspection image of the first pattern area with the defect detection standard created by the first design standard.
Defect inspection of the mask pattern is performed, and the defect inspection of the second mask pattern is performed by comparing the inspection image of the second pattern region with the defect inspection standard created by the second design standard. To do.

For example, having two or more mask pattern areas A1 to An,
And the design pattern standard R1 of each mask pattern area A1 ~ An
~ Rn is an inspection of different mask patterns 11, each mask pattern area A1 ~ An is defined as an inspection target area B1 ~ Bn, corresponding to the design pattern reference R1 ~ Rn of each mask pattern area A1 ~ An Defect detection criteria ε1 to ε
n is set for each of the inspection target areas B1 to Bn, and the defect of the mask pattern 11 is detected for each of the inspection target areas B1 to Bn based on the defect detection criteria ε1 to εn. To do.

[Action]

According to the present invention, the defect inspection of the mask pattern in which the first pattern region formed by the first design standard and the second pattern formed by the second design standard different from the first design standard are mixed is performed. When performing, the inspection image of the first pattern region and the inspection image of the second pattern region are separately acquired, and the first pattern region is inspected according to the inspection standard formed according to the first design standard. The second pattern area is inspected by the inspection standard formed by the second design standard.

Accordingly, in the present invention, when inspecting a mask pattern in which a plurality of pattern regions created by different design standards are mixed, a pattern region of a specific inspection standard is included so that a pattern region of another design standard is not included. Image is selectively acquired, and the acquired image is inspected based on the defect inspection standard of the same inspection standard, so that the inspection can be properly performed.

For example, the defect detection of the mask pattern is performed based on the defect detection criteria ε1 to εn set for each of the inspection target areas B1 to Bn and for each of the inspection target areas B1 to Bn.

Therefore, the inspection target area corresponding to the defect detection reference εi
For the inspection target area Bn other than Bi, the defect detection criterion εi
The defect detection based on is not performed. Therefore, in the inspection of the mask pattern in the inspection target area in which the defect detection reference εi does not correspond to the inspection target area Bn, it is possible to omit the conventional useless inspection time.

As a result, it is possible to eliminate the conventional process of determining a pseudo defect caused by a difference in defect detection standard.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

2 to 7 are diagrams for explaining the mask pattern inspection method according to the embodiment of the present invention, and FIG. 2 is a configuration diagram of the mask pattern inspection device according to each embodiment of the present invention.

In the figure, 11 is a mask pattern of a semiconductor integrated circuit or the like, and as shown in FIG.
Is different for each mask pattern area A1 to A3. Reference numeral 12 denotes an image acquisition unit, such as an optoelectronic imaging device that acquires an image of the mask pattern 11. An image storage unit 13 stores image data obtained by binarizing the image of the mask pattern 11. Defect detection / determination means 14 finds a defect by comparing / determining the defect detection reference data with the acquired image data.

Reference numeral 15 is an inspection data setting means, which defines each mask pattern area A1 to A3 of the mask pattern 11 as an inspection target area B1 to B3, and detects defects corresponding to the design pattern standards R1 to R3 of each mask pattern area A1 to A3. The criteria ε1 to ε3 are set for each of the inspection target areas B1 to B3.

Reference numeral 16 denotes an inspection data storage unit that stores coordinate data for dividing each mask pattern area and data of defect detection standards ε1 to ε3 corresponding to each of the design pattern standards R1 to R3.

Reference numeral 17 is a stage control means, and inspection data setting means
The stage on which the mask pattern 11 is placed is driven based on the coordinate data from 15.

With these, for example, an apparatus for detecting a defect directly from the actually manufactured mask pattern 11 is configured. In addition,
Before actually manufacturing the mask pattern 11, that is, at the stage of design data, for a device for detecting defects,
This will be described later with reference to FIG.

FIG. 3 is an explanatory diagram related to the mask pattern of each embodiment of the present invention.

In the figure, the mask pattern 11 has, for example, mask pattern regions A1 to R3 having different design pattern references R1 to R3.
The defect detection criteria ε1 to ε3 are different for each of the mask pattern areas A1 to A3.

For example, in the mask pattern 11, the mask pattern area A1 is an area other than the area surrounded by the coordinates a (x1, y1), b (x3, y1), d (x3, y3) and c (x1, y3). . Similarly, the mask pattern area A2 has coordinates a (x
1, y1), b (x3, y1), f (x3, y2), e (x2, y2), g (x2, y
It is a region surrounded by 3) and c (x1, y3).
Further, the mask pattern area A3 has coordinates e (x2, y2), f
It is a region surrounded by (x3, y2), d (x3, y3) and g (x2, y3).

FIG. 4 is a flowchart of the mask pattern inspection method according to the first embodiment of the present invention.

Here, for the mask pattern area A1, for example, the data of the design pattern reference R1 is 6 [μm], the defect detection reference ε.
The data of 1 is set to 5 [μm], and similarly, the data of the design pattern reference R2 is set to 3 [μ] for the mask pattern area A2.
m], the data of the defect detection reference ε2 is 2.5 [μm],
For the mask pattern area A3, the data of the design pattern reference R3 is 1 [μm], and the data of the defect detection reference ε3 is 1
[Μm] is assumed.

In the figure, first in step P1, the inspection storage means 16
The coordinate data of the mask pattern 11, the design pattern reference data, and the defect detection reference data are stored. At this time, coordinate data a (x1, y) for dividing the mask pattern areas A1 to A3
1), b (x3, y1), c (x1, y3), d (x3, y3), e (x2, y2), f
(X3, y2) and g (x2, y3) and design pattern standards R1 to R3
6, 3, 1 [μm] and data 5, 2.5, 1 [μm] of the defect detection criteria ε1 to ε3 are stored.

Then, in step P2, each mask pattern area A1 ~
A3 is defined as inspection target areas B1 to B3. At this time, as shown in FIG. 5 (a), the inspection target region B1 has coordinates a (x1, y
1), b (x3, y1), d (x3, y3) and c (x1, y3) are areas other than the area surrounded by the defect detection criterion ε.
It becomes the inspection target of 1. The inspection target area B2 is also an area surrounded by coordinates a (x1, y1), b (x3, y1), f (x3, y2), g (x2, y3) and c (x1, y3). Yes, this is the inspection target of the defect detection criterion ε2. Further, the inspection target area B3 is an area surrounded by the coordinates e (x2, y2), f (x3, y2), d (x3, y3) and g (x2, y3), and this is the inspection of the defect detection criterion ε3. Be the target.

Next, in step P3, defect detection criteria ε1 to ε corresponding to the design pattern criteria R1 to R3 of each mask pattern area A1 to A3.
3 is set for each of the inspection target areas B1 to B3. At this time, the inspection data setting means 15 instructs the stage control means 17 to coordinate data a (x
1, y1), b (x3, y1), d (x3, y3) and c (x1, y3) are sent, and the data 5 [μm] of the defect detection reference ε1 is sent to the defect detection judging means 14. In step P4, the defect is detected in the inspection target region B1 by the defect detection reference ε1. At this time, the image acquisition means 12 does not inspect areas other than the mask pattern area A1 and acquires an image only for the mask pattern area A1, and the defect detection determination means 14 through the image storage means 13. Thus, the defect detection is performed based on the data 5 [μm] of the defect detection reference ε1. For example, as shown in FIG. 5 (b), if there is a pattern in the mask pattern area A1 which is erroneously close to a pattern interval of 4 [μm] or 2 [μm], it is determined as defects E11 and E12. , Can be found.

Next, in step P5, the defect is detected in the inspection target region B2 by the defect detection reference ε2. At this time, the image acquisition unit 12 does not inspect the area other than the mask pattern area A2, acquires an image of only the mask pattern area A2, and detects defects as in the processing content of step P4. Data of the defect detection standard ε2 by the judgment means 14 2.5
Defect detection is performed based on [μm]. For example, in the mask pattern area A2, the pattern interval is mistakenly 2 [μ
If there is a pattern close to m], it can be found as a defect E2.

Then, in step P6, a defect is detected in the inspection target area B3 by the defect detection reference ε3. Also in this case, the image acquisition means 12 acquires an image only for the mask pattern area A3 without performing an inspection for areas other than the mask pattern area A3, and similarly to the processing content of step P4, the defect detection determination means 14 Therefore, the data of defect detection criterion ε3 is 1 [μ
defect detection is performed based on [m]. For example, in the mask pattern area A3, the pattern interval is erroneously 0.9 [μm].
If there is a pattern that is close to the
Can be found as defect E3.

FIGS. 5 (a) and 5 (b) are diagrams supplementing the flowchart of the first embodiment, and FIG. 5 (a) shows the inspection target regions B1 to B3 of the mask pattern 11 and the defect detection criteria ε1 to ε3. The relationship diagram with is shown.

Further, FIG. 3B is a diagram for explaining the defect inspection result of the mask pattern 11.

In the figure, E11, E12, E2, and E3 indicated by arrows are defects, and the defect detection criterion ε1 due to a design error, a design failure, or the like.
It is a portion having a pattern interval smaller than ˜ε3.

FIG. 6 is an explanatory diagram relating to the mask pattern inspection method of the second embodiment.

In the figure, the difference from the first embodiment is that in the second embodiment, when the entire surface of the image acquisition means 12 is scanned from the upper part to the lower part of the paper through the stage control means 17, the mask pattern areas A1 to Defect detection standard ε1 every time A3 changes
Defect detection is performed by changing ε3 as well.

Here, the coordinates a for dividing the mask pattern areas A1 to A3
~ G and the defect detection criteria ε1 to ε3 are the same as those in the first embodiment, first, for the acquired image data of the inspection region B1, based on the data 5 [μm] of the defect detection criteria ε1, Defect detection is performed.

Next, when the stage on which the mask pattern 11 is placed is moved so that the image acquisition means 12 enters the mask pattern area B2, the defect detection reference ε2 for the acquired image data.
The defect is detected based on the data 2.5 [μm] of the above. At this time, the inspection target areas B1 to B2 are changed by the inspection data setting means 15 on the basis of coordinate data a to g that divide the mask pattern areas A1 to A3 set in advance.
The coordinate data a to g are set in a register or the like, and when the count value of the stage movement data or the like of the stage control means 17 and the count value of the register match, for example, the stage is temporarily stopped and the image acquisition means 12 operates. The settings such as the magnification of the lens system are changed each time.

Even when the image acquisition unit 12 is scanned in the inspection target area B3, the image acquisition data acquired in the inspection target area B3 is based on the data 1 [μm] of the defect detection reference ε3.
Defect detection is performed.

As a result, by scanning the image acquisition means 12 once over the entire inspection object, defects E11, E12, E2 and E3 as shown in FIG. 5 (b) can be produced in a shorter time than in the first embodiment. It becomes possible to detect.

7 (a) to 7 (d) are configuration diagrams of a mask pattern inspection apparatus according to another embodiment of the present invention.
FIG. 3 shows an apparatus configuration for detecting defects by comparing the mask patterns 11a and 11b on the substrate.

Since the mask pattern device having the same name as that of FIG. 2 has the same function, its description is omitted.

As a result, it is possible to detect defects based on the mask pattern inspection method of the first and second embodiments.

FIG. 2B shows the device configuration when the mask pattern 11 on the substrate is compared with the design data of the magnetic tape storage means 20.

The design data read from the magnetic tape storage means 20 is converted into image display data by the data conversion means 21 and stored in the image storage means.

As a result, as in the case of FIG.
At 18, it is possible to detect defects based on the mask pattern inspection method of the first and second embodiments.

FIG. 3C shows an apparatus configuration in the case where the design data of the magnetic tape storage unit 20 is converted into data and a defect is detected.

According to this, as shown in FIGS. 7A and 7B, it is possible to remove the defect included in the design data in the stage before the mask pattern is created.

In the same figure (d), data conversion of both design data of the magnetic tape storage means 20a, 20b is performed, image display data is compared,
The apparatus structure when detecting a defect is shown.

According to this, it is possible to compare both design data in a short time and find a defect included in the design data.

In this way, according to each embodiment of the present invention, the data of the defect detection criteria ε1 to ε3 set for each of the inspection target regions B1 to B3 is based on 5,2.5,1 [μm] and Area B
The defects E11, E12, E2, and E3 of the mask pattern 11 are inspected every 1 to B3.

Therefore, the defect detection based on the data 5 [μm] of the defect detection reference ε1 is not performed on the inspection target regions B2 and B3 other than the inspection region B1 corresponding to the data 5 [μm] of the defect detection reference ε1. Therefore, it is possible to omit the conventional wasteful inspection time for the inspection of the mask pattern in the inspection target areas B2, B3 where the defect detection reference ε1 does not correspond to the inspection target area B1.

As a result, it is possible to eliminate the conventional process of determining a pseudo defect caused by the difference between the defect detection standards ε1 to ε3.

〔The invention's effect〕

As described above, in the present invention, when inspecting a mask pattern in which a plurality of pattern regions created by different design standards are mixed, a specific inspection standard is included so that a pattern region of another design standard is not included. Since the image of the pattern area is selectively acquired and the acquired image is inspected based on the defect inspection standard of the same inspection standard, the inspection can be properly performed in a short time.

Therefore, even if the semiconductor integrated circuit device is highly integrated and highly densified and the design pattern standard and the defect detection standard are increased, the entire mask pattern can be inspected in a short time.

As a result, the inspection time for one mask pattern can be shortened, which greatly contributes to the improvement of the processing efficiency of the mask pattern inspection apparatus.

[Brief description of drawings]

1 (a) and 1 (b) are principle diagrams relating to a mask pattern inspection method of the present invention, FIG. 2 is a configuration diagram of a mask pattern inspection apparatus according to each embodiment of the present invention, and FIG. Explanatory drawing concerning the mask pattern of each embodiment of the present invention, FIG. 4 is a flow chart concerning the mask pattern inspection method of the first embodiment of the present invention, and FIGS. 5 (a) and 5 (b) are
The figure which supplements the flowchart of the 1st Example of this invention, FIG. 6 is explanatory drawing which concerns on the mask pattern inspection method of the 2nd Example of this invention, and FIGS. 7 (a)-(d) are FIG. 8A and FIG. 8B are configuration diagrams of a mask pattern inspection device according to another embodiment of the present invention, which are explanatory diagrams related to a mask pattern inspection method of a conventional example. (Description of symbols) 11 ... Mask pattern, A1 to An ... Mask pattern area, B1 to Bn ... Inspected area, R1 to Rn ... Design pattern reference, ε1 to εn ... Defect detection reference.

Claims (1)

[Claims] 1. In the same plane, a first mask pattern is formed in a first pattern area according to a first design standard, and a second mask area is formed with a first mask pattern larger than the first mask pattern. A second mask pattern is a method for inspecting a defect of an object to be inspected formed by a second design standard different from the first design standard, wherein a first pattern region of the first pattern region is formed in accordance with the first design standard. A defect inspection standard is created, a defect inspection standard for the second pattern region is created in accordance with the second design standard, and the first pattern region and the second pattern region are associated with the defect inspection standard. An inspection image is acquired, the inspection image of the first pattern area is compared with a defect inspection standard created by the first design standard, and a defect inspection of the first mask pattern is performed. Inspection image Mask pattern inspection method, characterized in that in comparison with a defect inspection standard that created a defect inspection of the second mask pattern by the second design criteria and.