JPH02139676A - Inspection equipment - Google Patents

Abstract

PURPOSE:To decrease inspection data quantity and to shorten an inspection time by varying a scanning width based on the shape of a pattern formed for a mask to be inspected, and repeatedly using the same data. CONSTITUTION:When the same pattern 2 is repeatedly formed on a reticule 1, the scanning width of the title inspection equipment is varied, and the scanning width accordant with a repeated pitch is to be used at the side of the inspection equipment. Namely, the pattern data of the whole of a repeated part can be obtained, and the same pattern can be repeatedly used in plural cases by giving the data of scanning widths (a)-(c) to the inspection equipment. Thus, the data quantity can be decrease, and the inspection time can be shortened.

Description

[Detailed Description of the Invention] Industrial Application Fields Prior Art (Figure 3) Problems to be Solved by the Invention Examples of Means and Actions for Solving the Problems First Embodiment of the Invention (Figure 1) Book Second embodiment of the invention (Figure 2) Effects of the invention [Summary] Regarding an inspection device, it is possible to reduce the amount of data, shorten data production time, improve efficiency of data handling, and shorten inspection time. The purpose of the present invention is to provide an inspection device that scans the surface of a mask to be inspected on which a predetermined pattern is formed in the horizontal direction, and when the scan reaches the edge of the mask, steps vertically by a predetermined scanning width. In an inspection apparatus that inspects a mask to be inspected by starting a next-stage scan, extracting mask data, and comparing the mask data with predetermined design data, the scanning width is determined based on the shape of the pattern. It is configured so that the same pattern of mask data is used at multiple locations for inspection.

[Industrial application field]

The present invention relates to an inspection apparatus, and more particularly to an improvement in a database inspection apparatus for inspecting reticles and masks used in semiconductor manufacturing processes.

The process from LSI design to mask drawing usually involves the following steps:
Layout design is performed based on the circuit design, MT for pattern generator or electron beam writing is manufactured through artwork work, and a mask is manufactured based on this data (MT). After mask inspection, defective parts are corrected and used in the process, but with the method of reducing and projecting the mask to be inspected (reticle), defects are transferred to all chips, so a defect-free mask is required. , the mask manufacturing process, including defect correction methods, is extremely important.

Defect correction methods include the data comparison method, which detects defects by comparing the mask (reticle) to be inspected with standard data, and the data comparison method, which detects defects by comparing two chips with the same pattern within the mask (reticle) to be inspected. There is a chip comparison method for detection, and the latter method can be used when a plurality of chips with the same pattern are lined up in a mask. Since defects often occur independently on each chip, the latter method can also adequately detect defects. However, defects that occur commonly between chips cannot be detected. Common defects between chips occur, for example, when a reticle has a defect or dust adhesion, and this occurs on a full-size mask that is photorepeated.

Furthermore, although the former method is complete, it takes 5 to 10 times as long as the latter method. Reticles are particularly inspected by the former method because they are required to be defect-free. These inspection devices are automated and output defect maps with defect locations recorded on magnetic cards or the like.

In recent years, database inspection equipment is capable of handling high-density IC elements,
In order to cope with the increase in scale, the amount of test data has been compressed, making it possible to perform efficient tests.

[Conventional technology]

As a conventional defect inspection apparatus of this type, there is one shown in FIG. 3, for example. In the figure, 1 is a mask (reticle) to be inspected, and 2 is a pattern formed on the reticle. Further, 3 is an imaging device with a microscope that photographs the surface of the reticle 1, and 4 is a magnetic tape (M
T), 5 is an image processing system, and 6 is a defect extraction device.

In the above configuration, the surface of the mask 1 to be measured is imaged on the imaging device 3 with a microscope, and a small area is enlarged and taken into the image processing system 5. The image processing system 5 divides the screen of this small head area into rows of pixels and determines whether each pixel is black or white. This is compared with the design data contained in the magnetic tape 4 by the defect extraction device 6, and if there is a difference, it is recorded as a defect. The scanning method is to move the mask 1 in the X direction (horizontal direction), and when the next small area comes directly under the microscope, it is taken into the image processing system 5 and the inspection is repeated. When it reaches the end of the mask, the mask 1 is moved. Y
Stepping is performed by a fixed scanning width in the direction (vertical direction) and the next stage of inspection is performed. The above operation is repeated to inspect the entire surface of the mask 1. If pixels are taken finely during inspection, the inspection will be complete, but the inspection time will increase. Usually, the pixel size is set to 0.5 to 1 μm square, and defects up to that size are extracted. In this way, the pattern is photographed and inspected while continuously moving the mask 1, but the pattern density that can be inspected is limited by the processing speed for developing the reference pattern from the design data.

[Problem to be solved by the invention]

However, in such conventional database inspection equipment, the scanning width is constant, so even if the same pattern exists in the element, the data is not produced as the same pattern, resulting in a large amount of data. There was a problem that the

For example, even if the same pattern 2 is formed on the reticle 1 as shown in Fig. 3, the scanning width is fixed as shown in the broken line in the figure, so The shape of the pattern recognized differs for each scanning line, and the pattern information manually entered as data into the image processing system 5 after scanning differs for each scanning line. Therefore, even if the input data is the same pattern, all the input data will be recognized as different, and the large amount of data will not be resolved.

In general, the amount of inspection data is larger than the data for exposure, so how to reduce this amount of data is the key to reducing data production time, improving data handling efficiency, and shortening inspection time. This is an important point.

Therefore, the present invention provides an inspection device that can reduce the amount of data by using repeated pattern data multiple times, thereby reducing data production time, efficient data handling, and inspection time. is intended to provide.

(Means for Solving the Problems) In order to achieve the above object, an inspection apparatus according to the present invention horizontally scans the surface of a mask to be inspected on which a predetermined pattern is formed, and when the scanning reaches the end of the mask, a predetermined In an inspection apparatus that inspects the mask to be inspected by stepping vertically by a scanning width to start the next scanning, extracting mask data, and comparing the mask data with predetermined design data, the scanning The inspection apparatus is characterized in that the width is made variable based on the shape of the pattern, and mask data of the same pattern is used at a plurality of locations for inspection.

[Effect]

In the present invention, the scanning width is varied based on the shape of the pattern formed on the mask to be inspected.

Therefore, the pattern information taken in as data by scanning becomes equal for each same pattern, and the same data can be used repeatedly. As a result, the amount of data for inspection can be reduced, and the inspection time can be shortened.

〔Example〕

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

FIG. 1 is a diagram showing a first embodiment of an inspection apparatus according to the present invention. First, the configuration will be explained. Components that are the same as those of the conventional example shown in FIG. 3 are given the same numbers and their explanations will be omitted.

In FIG. 1, 1 is a reticle, and the same pattern 2 is repeatedly formed on the reticle 1. In FIG. In such a case, in this embodiment, the scanning width of the inspection device is changed.

Specifically, when the fixed scanning width of the device is 200 μm and the pattern repetition pitch is 510 μm, in the conventional example, the shape of the pattern included in each scan is different, so all scans However, in this example, the scanning width is made variable, and the scanning width is adjusted to the repetition pitch (in this case, the scanning width is 170 μm).
) is taken by the inspection equipment, so the scanning width a,
By having only three types of data b and c, pattern data for the entire repeating portion can be obtained. That is, as shown by the broken line in the figure, scanning has the same pattern as a, b, and c, and the same pattern can be used repeatedly in a plurality of cases.

In this way, in this embodiment, when the same pattern is repeated, the same data can be used repeatedly by changing the scanning width of the device. Therefore, I.C.
As the integration level and number of patterns increase, even if the amount of data becomes a problem, it is possible to reduce the amount of data for inspection and enable rapid reticle production. can.

FIG. 2 is a diagram showing a second embodiment of the inspection device according to the present invention, and the same components as those of the first embodiment shown in FIG. 1 are given the same numbers. In Fig. 2, 10 is a reticle;
Reference numeral 11 indicates a pattern, and the hatched portions of the pattern 11 represent the same pattern, each of which is made up of repeating units 12. In this embodiment, the scanning width is made variable so that only the data of the repeating unit 12 of the pattern 11 at the lower right of the figure is included. Therefore, by using repeated expressions, the pattern of the entire hatching can be inspected.

[Effects of the Invention] According to the present invention, the amount of data can be reduced, and data production time, data handling efficiency, and inspection time can be reduced.

FIG. 2 is a diagram showing the relationship between pattern repetition and scanning width showing a second embodiment of the inspection apparatus according to the present invention, and FIG. 3 is an overall configuration diagram of a conventional inspection apparatus.

1.10... Reticle (mask to be inspected), 2.
11... Pattern, 3... Imaging device with microscope, 4... Magnetic tape (MT), 5... Image processing system, 6... ...Defect extraction device, 12...Repetition unit.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between pattern repetition and scanning width of a first embodiment of the inspection apparatus according to the present invention, 1. Niticle (mask to be inspected) 2: Pattern repetition and scanning width of pattern 1st example Xa 10 Niticle 11: Pattern L28 Repetition unit No. 2': A diagram showing the relationship between pattern repetition and scanning width for three examples FIG. 2 Overall configuration diagram of a conventional inspection device FIG. 3 : Photographic device with microscope 4: W1 tape (MT)

Claims (1)

[Claims] The surface of a mask to be inspected on which a predetermined pattern is formed is scanned in the horizontal direction, and when the scan reaches the end of the mask, the next stage of scanning is started by stepping vertically by a predetermined scanning width. In an inspection apparatus that inspects the mask to be inspected by extracting mask data and comparing the mask data with predetermined design data, the scanning width is made variable based on the shape of the pattern;
An inspection device characterized in that inspection is performed using mask data of the same pattern at multiple locations.