JPH10161299A - Pattern fault investigation device - Google Patents

Abstract

(57) [Summary] [Problem] To provide a simple abnormality cause identification method that does not select operator skills. SOLUTION: Coordinate conversion means for converting abnormal pattern coordinates of a mask to be investigated into coordinates on the mask, image generating means for generating a plate image corresponding to an exposure pattern on the mask, and abnormal pattern coordinates converted by the coordinate converting means Coordinate specifying means for specifying the coordinates on the plate image using the method, area specifying means for specifying the deflection area of the optical system of the exposure apparatus used for exposing the mask from the specified coordinates, a pattern in the deflection area of the optical system Alternatively, an output unit is provided for outputting debug information including exposure information on the pattern in a viewable state or a state in which data processing is possible.
The abnormal pattern coordinates of the inspection target mask expressed in a coordinate system different from that of the exposure apparatus are converted into the coordinate system of the exposure apparatus, and the coordinates are specified by the coordinate specifying means and the area specifying means in the common coordinate system, and the optics including the abnormal pattern is used. Automate the identification of the deflection region of the system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern failure inspection apparatus, and more particularly, to an apparatus suitable for application to pattern diagnosis of an exposure mask of a semiconductor integrated circuit. In addition,
Throughout this specification, mask and reticle are treated as synonyms, and exposure and drawing are also treated as synonyms.

[0002]

2. Description of the Related Art In recent years, as the scale and density of semiconductor integrated circuits have increased, the pattern of a mask for exposure has further increased in complexity, and pattern abnormalities have frequently occurred at a frequency that cannot be ignored. Was. So, TAT
In order to improve (turnaround time), there is a need for a simple method of identifying the cause of an abnormality that does not depend on the skill of the operator.

FIG. 3 is a diagram illustrating a process of generating (exposing) a mask pattern. Here, an example of a very simple and simple pattern is shown for convenience of explanation and illustration.
First, a part pattern necessary for the final pattern shape to be exposed on the mask is extracted from the pattern library. In the example, a horizontal “day” character pattern (hereinafter, pattern 1) and a square pattern (hereinafter, pattern 2) that fits in the “mouth” of the “day” character pattern are conveniently extracted. . Note that all the part patterns including these extracted patterns are stored in a compressed state in the library in order to reduce the data amount. That is, the extracted pattern 1 is data composed of various numerical information including center position coordinates (Y1, X1), and similarly, pattern 2 is data composed of various numerical information including center position coordinates (Y2, X2). The mask exposure apparatus performs image reproduction processing for developing these data into a plate image. Here, the plate image is a real image of a final shape pattern to be exposed on a mask material called a plate, and the substance exists digitally in the buffer memory. For example, if the buffer memory is treated like an image frame memory, the whole or a part of the pattern image can be enlarged and visually confirmed on the display. The mask exposure apparatus drives an exposure system to expose a pattern similar to a plate image on a plate.

Now, it is assumed that, in the mask inspection process after exposure, for example, an abnormality is found in the pattern 2 marked with x. In this case, it is necessary to specify whether the cause of the abnormality is the part pattern itself in the library, the process of developing the plate image, or the malfunction of the exposure system.

[0005]

To identify the cause of the abnormality,
In general, (1) recheck all data, or
(2) There is a method of narrowing down the cause by trial and error by repeating the exposure process while changing the conditions,
The method (1) is extremely inefficient and impractical, especially for masks for large-scale integrated circuits, and the method (2)
Highly skilled operators who are familiar with the entire exposure process are required; without such operators, it is impossible to find the cause unless accidents are expected, and trial and error for transient abnormalities in the first place Neither method (1) nor (2) can be said to be a drastic measure because it cannot be used at all, and the solution is to provide a simple method for identifying the cause of abnormalities regardless of the skill of the operator. There were technical issues to be addressed.

[0006]

According to the present invention, there is provided a pattern failure investigation apparatus, comprising: coordinate conversion means for converting abnormal pattern coordinates of a mask to be investigated into coordinates on the mask; Image generating means for generating a plate image; coordinate specifying means for specifying coordinates on the plate image using abnormal pattern coordinates converted by the coordinate converting means; and using the specified coordinates for exposing the mask. Region specifying means for specifying a deflection region of the optical system of the exposure apparatus, and outputting a pattern in the deflection region of the optical system or debug information including exposure information relating to the pattern in a visible state or a data processing state. And output means for performing the operation.

[0007] Alternatively, the pattern fault investigation device according to the present invention may be provided on a medium storing a program for realizing the coordinate conversion means, the coordinate specifying means, the area specifying means, and the output means. In the present invention, since the abnormal pattern coordinates of the mask to be inspected expressed in a coordinate system different from that of the exposure apparatus are converted to the coordinate system of the exposure apparatus by the coordinate conversion section, the coordinates of the coordinates by the coordinate specifying section and the area specifying section are converted. The specification can be performed in a common coordinate system, and the specification of the deflection region of the optical system including the abnormal pattern can be automated. Therefore, since no special skills are required of the operator, it is possible to provide a simple method of identifying the cause of abnormality which can be easily used by anyone with good reproducibility. Alternatively, an extremely useful technology that greatly contributes to cost reduction can be realized.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 and FIG. 2 are diagrams showing an embodiment of a pattern fault investigation device according to the present invention. First, an overall configuration to which the apparatus of the present embodiment is applied will be described. FIG. 1 is a conceptual diagram, and 10 is an exposure apparatus.

The exposure apparatus 10 exposes a pattern on a mask (not shown) in accordance with design data, and provides a part library for providing part patterns (for example, reference numerals 1 and 2 in FIG. 3) necessary for the pattern to be exposed. An exposure computer (corresponding to an image generating means described in the gist of the invention) 14 for generating a pattern arrangement information file (plate image) 12 according to design data by combining 11 and part patterns and storing the generated file in a buffer memory unit 13. In addition, a pattern generation unit 15 for generating various pattern signals based on a pattern array information file stored in the buffer memory unit 13 and a pattern correction unit 1 for performing required correction on the pattern signals and outputting the corrected signals
And a pattern signal generator 17 including:
A lens barrel (not shown) having an exposure optical system, a lens barrel controller 18 that controls the lens barrel in accordance with a signal from a pattern signal generator 17, and the like are provided.

Reference numeral 20 denotes an inspection apparatus for inspecting an abnormal pattern of a mask created by the exposure apparatus 10. This inspection device 2
For 0, for example, a pattern for detecting a match / mismatch by comparing images of the same pattern on a mask and a pattern for detecting a match / mismatch by comparing an image between a pattern on a mask and a design pattern can be used. . In any case, the occurrence of an abnormal pattern can be determined when a mismatch is detected.

The inspection data of the inspection apparatus 20, that is, the data including the abnormal pattern coordinate information of the inspection target mask is stored in a portable medium 21 such as a floppy as shown in the figure, or a physical data transfer line such as a network. Is passed to the research computer 22 via Research computer 22
Reads the data (referred to as data A for the sake of convenience) from the inspection apparatus 20, performs preprocessing such as format conversion if necessary, and then executes the following characteristic processing. The first processing (see FIG. 2) is for converting the coordinate system of the data A (the coordinate system of the inspection apparatus 20) to the coordinate system of the exposure apparatus 10, and corresponds to the coordinate conversion means described in the gist of the invention. . For example, in the case of the inspection apparatus 20 that performs image comparison, a fixed pattern such as an alignment mark (positioning mark) provided on a mask or a reticle cover (a protection area for avoiding overlap with an adjacent exposure area) is used. Since image recognition can be performed, coordinate conversion can be performed using the fixed pattern position as reference coordinates. Second processing (see FIG. 2) A pattern arrangement information file 12 used for exposing the inspection target mask is acquired from the exposure apparatus 10, and the pattern arrangement information file 12 (referred to as data B for convenience) and the coordinates after the coordinate conversion are obtained. The abnormal pattern coordinates on the data B are specified by comparing the data A with the data A, and the deflection area of the optical system of the exposure apparatus 10 is specified based on the abnormal pattern coordinates. Therefore, the second processing corresponds to the coordinate specifying means and the area specifying means described in the gist of the invention.

In this embodiment, the main deflection and the sub deflection are used.
Assuming application to an exposure apparatus 10 having a stage optical system,
After specifying the main deflection area, the sub deflection area included in the main deflection area is specified, but the invention is not limited to this. If there is only one of the main and sub deflection systems, only the deflection area of that deflection system needs to be specified from the abnormal pattern coordinates. Third processing (see FIG. 2) The specified sub-deflection area is further narrowed down to the accuracy of the inspection device 20 (the accuracy of data A) to specify the final area including the abnormal pattern, and then the area is displayed on the display. In addition to displaying an enlarged image in an arbitrary range centered on the data, various data necessary for debugging (for example, coordinate information of the main / sub change area, abnormal pattern address information of the buffer memory unit 13, graphic information of the abnormal pattern, etc.)
Is displayed on a display, printed on a list, or formatted in a state where data processing is possible, and stored in a storage device. Therefore, this third processing corresponds to the output means described in the gist of the invention.

According to the above arrangement, the abnormal pattern coordinates of the inspection target mask expressed in the coordinate system of the inspection apparatus 20 different from the exposure apparatus 10 are converted into the coordinate system of the exposure apparatus 10 by the first processing. Therefore, the coordinate processing by the second processing can be performed in the common coordinate system, and the specification of the deflection region of the optical system including the abnormal pattern can be automatically performed, which provides an advantageous operation and effect not found in the related art.

Although the survey computer 22 is provided separately in the embodiment, the present invention is not limited to this. The above-described first to third processing units may be incorporated in the exposure computer 14. Alternatively, when the survey computer 22 is provided separately, it may be connected to a plurality of exposure apparatuses 10 via a network. Or, in general, a program used in hardware is provided in a state recorded on a “medium” (regardless of whether the program is executable or not). The medium generally refers to a portable medium such as a floppy disk, MO, CD-ROM, memory card, ROM chip, etc. However, a fixed storage device (hard disk) can be removed from the device and transported, or a program can be installed in advance. The hard disk on which the program is written is a worthy medium because it is sometimes provided by a computer. When a program is distributed via a network or a communication line, the storage device of the distribution source is also a medium. If a program in which the first processing, the second processing, and the third processing are described in code is recorded on such a medium and provided to a user, the user can store the program in a memory (including a virtual memory including a virtual memory) of a hardware system. ), The program can be executed to construct a pattern fault investigation device including the coordinate conversion means, coordinate identification means, area identification means, and output means described in the gist of the invention.

[0015]

According to the present invention, it is possible to provide a simple method for specifying the cause of an abnormality which can be easily used by anyone with good reproducibility without requiring an operator having a special skill. For the field of manufacturing exposure masks,
An extremely useful technology that greatly contributes to TAT shortening or cost reduction can be realized.

[Brief description of the drawings]

FIG. 1 is a conceptual overall configuration diagram of an embodiment.

FIG. 2 is a schematic processing flowchart of an embodiment.

FIG. 3 is a schematic view of a process of generating a mask pattern.

[Description of Signs]: First processing (coordinate conversion means): Second processing (coordinate specifying means and area specifying means): Third processing (output means) 10: exposure apparatus 12: pattern arrangement information file (plate (Image) 14: Exposure computer (image generation means)

Claims (2)

[Claims] 1. Coordinate conversion means for converting abnormal pattern coordinates of a mask to be examined into coordinates on the mask; image generation means for generating a plate image corresponding to an exposure pattern on the mask; Coordinate specifying means for specifying the coordinates on the plate image using the abnormal pattern coordinates converted by the method, and area specifying for specifying a deflection area of an optical system of an exposure apparatus used for exposing the mask from the specified coordinates. Means for outputting a pattern in the deflection area of the optical system or debug information including exposure information related to the pattern in a state in which the pattern can be viewed or data can be processed. Fault investigation device. 2. A medium storing a program for realizing the coordinate converting means, coordinate specifying means, area specifying means, and output means according to claim 1.