JPH03163845A - Pattern inspection device - Google Patents

Abstract

PURPOSE:To enable the true defective patterns to be inspected very efficiently by a method wherein the involving relations are referenceinspected making use of an inspection reference pattern changing the shifting amount in the specific directions. CONSTITUTION:An inspection reference pattern 3 is made by shifting a target pattern which is made according to a specific design data in specific shifting amounts of a', b' in the specific directions so as to perform the inspection making reference to the involving relations between said inspection reference pattern 3 made by said procedures and a pattern to be inspected. Accordingly, the optimum shifting amount can be set up conforming to the design rules to minimize the formation of false defective patterns. Through these procedures, the true defective patterns can very efficiently be inspected.

Description

[Detailed Description of the Invention] [Table of Contents] Overview Industrial Application Fields Prior Art (Fig. 8) Problems to be Solved by the Invention Embodiments of Means and Actions for Solving Problems to be Solved Explanation of the Principle of the Invention (Fig. 1) ) One embodiment of the present invention (Figures 2 to 7) Effects of the invention [Summary] Regarding a pattern inspection device, even a high-density pattern can be inspected according to the optimum tolerance, and pseudo-defect patterns can be detected. The purpose of the present invention is to provide a pattern inspection device that can efficiently inspect true defect patterns by reducing the occurrence of defective patterns. , a pattern inspection device that inspects the inspection mask by comparing and checking the pattern to be inspected with a predetermined inspection reference pattern, the inspection reference pattern being a target pattern created based on predetermined design data. The pattern is inspected by comparing the connotative relationship between the inspection reference pattern created by shifting the pattern by a predetermined shift amount in a specific direction and the pattern to be inspected, which is created by shifting the pattern by a predetermined shift amount in a specific direction. to take action.

[Industrial application field]

The present invention relates to a pattern inspection apparatus, and more particularly to inspection of LSI patterns in semiconductor product manufacturing.

Due to the miniaturization and high density of LSI patterns in recent years, design rule checking for specific directions has started to cause problems such as detecting a large number of pattern width and pattern spacing violations in directions that do not violate design rules. There is. Therefore, there is a need for a means to appropriately prevent design rule changes from being detected in directions unrelated to the inspection target.

[Conventional technology]

As a method of checking the design rules of conventional patterns,
For example, there is a pattern inspection apparatus shown in FIG. In FIG. 8, in this pattern design rule checking method, the target pattern data 1 for pattern formation is changed to an inspection reference pattern (data ) 2 and the inclusion relationship of the pattern to be inspected, an inspection method is adopted in which a pattern that violates a design rule is inspected.

[Problem to be solved by the invention]

However, in such conventional pattern inspection equipment, the pattern shape or target pattern data is simply shifted by the design rule tolerance value, so the actual design rule does not include the direction. There are many rules with different tolerance values, and if you check in the direction with a larger tolerance value, it will not be possible to detect rule violations in the direction with a smaller tolerance value, and if you check in the direction with a smaller tolerance value, it will not be possible to detect rule violations. It was difficult to detect rule violation patterns because even parts with large values that did not violate the rules were detected. Therefore, in a high-density pattern, a large number of pseudo-defect patterns are detected when inspected according to a small tolerance, making it difficult to fix true defect patterns.

Therefore, the present invention has developed a pattern that allows even high-density patterns to be inspected according to the optimum tolerance, thereby preventing the occurrence of false defective defects and efficiently inspecting true defective defects. The purpose is to provide inspection equipment.

[Means to solve the problem]

To achieve the above objectives, the pattern inspection device according to the present invention has the following features:
A pattern inspection device that scans the surface of a mask to be inspected on which a predetermined pattern is formed, extracts a pattern to be inspected, compares and verifies the pattern to be inspected with a predetermined inspection reference pattern, and inspects the mask to be inspected. The inspection criterion pattern is created by shifting a target pattern created based on predetermined design data by a predetermined amount in a specific direction, and shifting the target pattern by a predetermined shift amount in a specific direction. Inspection is performed by comparing the connotation relationship between the inspection reference pattern created in this manner and the pattern to be inspected.

[Effect]

In the present invention, the target pattern (original pattern) created based on design data is
Shift 1 by a predetermined shift amount in the axial direction, θ1 to θ7 directions)
- An inspection reference pattern is created, and the connotation relationship between the inspection reference pattern and the pattern to be inspected is verified.

Therefore, the optimum shift amount (tolerance) is set in accordance with the design rules, the occurrence of false defect patterns is significantly reduced, and true defect patterns are efficiently inspected.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

Eradication theory group FIG. 1 is a diagram for explaining the principle of the present invention.

The above-mentioned problem can be solved by comparing and checking the inclusion relationship using the test reference pattern 3 in which the shift amount a'b' (where a'≠b') is changed depending on the specific direction.

Two-pointed plate Next, a pattern inspection apparatus based on the above principle will be described as an example. ...Figures 2 to 7 are diagrams showing an embodiment of the present invention. FIG. 2 is a diagram showing the hardware structure of a mask pattern inspection device for carrying out this method.
This is an example of inspecting a mask pattern formed on a reticle. In this figure, 11 is a mask pattern inspection device (pattern inspection device), 12 is a mask placed on stage l3, and has a mask pattern 12a formed thereon (
Alternatively, the mask pattern 12a formed on the mask (or reticle) 12 is
For example, a small area is enlarged by an image acquisition means 14 consisting of an image pickup device with a microscope and taken into the image storage 15, and the image storage means 15 divides the screen of this small area into fine pixels and determines whether each pixel is black or white. Store image information.

On the other hand, the design data stored in the magnetic table l6 is read by the magnetic tape reading stage l7, and the read design data is converted into predetermined image data by the data conversion stage 18, and then the image shift stage 19 According to the processing method shown in FIG. 4, which will be described later, the pattern is shifted and outputted to the image storage means 20 as a reference pattern. The inspected pattern stored in the image storage means 15 and the reference pattern stored in the image storage stage 20 are output to the defect detection and judgment means (pattern comparison means) 2l, and the defect detection and judgment stage 21 determines the pattern coordinate position. , the reference pattern and the pattern to be inspected are compared and verified according to the output from the position control means 22. The pattern coordinate position control means 22 outputs a predetermined control signal to the stage 13, the magnetic tape reading means 17, and the defect detection/judgment stage 2l to control these, thereby controlling the pattern coordinate position.

Next, the operation will be explained, but first, the connotative relationship between the inspection reference pattern and the pattern to be inspected will be described.

The pattern shape inspection method in this embodiment uses an inspection standard in which the pattern to be inspected (pattern A) is shifted (enlarged or reduced) in a specific direction (for example, the X-axis direction and the Y-axis direction) as shown in FIG. Create a pattern (pattern B),
The mutual inclusion relationship between the inspection reference pattern (pattern B) and the target pattern to be inspected (pattern A) is compared and inspected. In other words, the pattern A in FIG. 3 is a diagram showing an example of a case where it is nonconforming because it is larger than the pattern B. In this diagram, the length (width) of the pattern to be inspected (pattern A) in the X-axis direction is WA, the length (height) in the Y-axis direction is lA, and the length (width) in the X-axis direction of the reference pattern (pattern B) is W
．． , the length (height) in the Y-axis direction is lB, and the tolerance values in the X-axis direction (one side) and Y-axis direction (one side) are ΔX and Δy, respectively.
Then, when WB≧wa+2ΔX, → pattern A is included in pattern B, and the positive pattern (X
direction rule), and when WB < WA +2ΔX, → pattern A is not included in pattern B and becomes a defective pattern (X direction rule).

Moreover, when lB≧AA+2Δy, the pass pattern A is included in the pattern B, and the normal pattern (Y
When aB<AA+2Δy, the pass pattern A is not included in the pattern B and becomes a defective pattern (Y direction rule).

FIG. 4 is a flowchart showing a standard pattern 10 pattern behavior program that is not processed by the image shift means 19.
The reference pattern shown in FIG. 5 is created by this flow.

In the figure, P I""' P s indicates each step of the flow, and the processing order from step P1 to step P4 is arbitrary. First, when the reference pattern creation or program starts, in P1, for designing the mask pattern layout of the designed product, the X-axis direction pattern shift is set based on the reference pattern width and pattern spacing tolerance values (X-axis direction pattern shift value In P2, for the mask pattern layout design of the designed product, the Y-axis direction pattern shift is set based on the standard pattern width and pattern interval tolerance values (Y-axis direction pattern shift value setting).

Next, in P3, for the mask pattern layout design of the designed product, set the θ1 direction pattern shift based on the standard pattern width and pattern spacing tolerance (θ1 direction pattern shift value setting), and in P4, set the pattern shift in the θ1 direction for the mask pattern layout of the designed product. Set θ and directional pattern shift based on the pattern layout design frame, standard pattern width, and pattern spacing tolerance (θ
7 direction pa 11? tone shift value setting). In this embodiment, in addition to the X-axis direction pattern shift value and the Y-axis direction pattern shift value, only the θ1 direction pattern shift value is required for the original pattern before conversion, as shown in FIG. 5(a). The process of step P4 is unnecessary. Next, in P5, as shown in FIG. 5(b), conversion processing (pattern shift processing) into a pattern is performed using straight lines obtained by pattern shift processing of each line segment based on pattern shift values in the vertical direction of pattern composition lines. This completes the creation of the reference pattern. As a result, a reference pattern as shown in FIG. 5(C) is created after conversion.

FIG. 6 is a flowchart showing a defect detection program processed in the defect detection judgment stage 21.

First, P. As shown in FIG. 7(a), the reference pattern and the pattern to be inspected are compared and matched, and in P1■, by matching between the patterns, the line segment coordinate values of the pattern to be inspected that are not included in the reference pattern are detected ( defect detection). Next, in the set of defect coordinates detected by PI3, the coordinate values at both ends of the line segment 12 of the set of straight line segments are detected, and the defective line segment is displayed at PI4, and a defect image such as the coordinate values at both ends of the defective line segment is displayed. , output the data and finish the process. As a result, a line segment in the pattern structure that causes a defect as shown by the large solid line in FIG. 7(b) is detected.

As described above, when changing the design rules for IC and LSI patterns, the original pattern is shifted in specific directions (in this example, the X-axis direction, Y-axis direction, and θ direction) by predetermined shift values. Create an inspection standard pattern,
The connotative relationship between the inspection reference pattern and the pattern to be inspected whose pattern size shift it differs depending on the specific direction is compared and inspected. Therefore, even if there are many design rules with different tolerance values depending on the direction, the optimal shift N (tolerance value) can be set for each direction, and the rule violation pattern due to the large or small tolerance value can be prevented. It is possible to prevent a decline in detection accuracy and accuracy. Especially when inspecting high-density patterns,
This solves the problem that a large number of pseudo-defect patterns are detected when inspecting according to a small tolerance value, making it difficult to fix true defect patterns. As a result, pattern inspection can be made more efficient and inspection time can be significantly shortened.

〔Effect of the invention〕

According to the present invention, even a high-density pattern can be inspected according to the optimum tolerance, the occurrence of false defect patterns can be reduced, and true defect patterns can be efficiently inspected.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention, FIGS. 2 to 7 are diagrams showing an embodiment of a pattern inspection device according to the present invention, FIG. 2 is a diagram of the structure of the mask pattern inspection device, and FIG. The figure is a diagram for explaining the connotative relationship between the inspection reference pattern and the pattern to be inspected, FIG. 4 is a flowchart showing a program for creating the reference pattern, l4 FIG. 5 is a diagram showing an example of creating the reference pattern, Figure 6 is a flowchart 1 showing the defect pattern detection program.
・, FIG. 7 is a diagram showing an example of defect pattern detection, and FIG. 8 is a diagram showing a conventional pattern inspection device. 11...Mask pattern inspection device), I2...Mask, 12a...Mask pattern, 13...Stage, 14...1 Image acquisition means, 15... Image storage means, 16... Magnetic tape, 17... Magnetic tape reading means, 18...
・Data conversion means, 19... Image shifting means, 20... Image storage means, 21... Defect detection judgment means, (Pattern detection 15 22-... Pattern coordinate position control means. l6 JP-A-3 163845 (7) (a) Opening: Reference pattern box': Pattern to be inspected (b) Pattern composition line segment that causes a defect An example of detecting a defective pattern in an embodiment is shown. Figure 7 Figure 1';) 7, Ii- a=b Figure 8 showing a conventional pattern inspection device

Claims (1)

[Claims] A method of scanning the surface of a mask to be inspected on which a predetermined pattern is formed to extract a pattern to be inspected, and inspecting the mask by comparing and collating the pattern to be inspected with a predetermined inspection reference pattern. A pattern inspection device that performs the inspection, wherein the inspection reference pattern is created by shifting a target pattern created based on predetermined design data by a predetermined shift amount in a specific direction; A pattern inspection apparatus characterized in that a pattern inspection is performed by comparing a connotation relationship between an inspection reference pattern created by shifting and the pattern to be inspected.