JPS60103617A - Device for inspection and amendment of defect - Google Patents

Abstract

PURPOSE:To achieve the full automation of inspection and amendment of pattern defects and to contrive improvement in product manufacturing efficiency and yield by providing an amendment part for irradiating a defective part with a laser beam based on the signals from an inspection part. CONSTITUTION:Objective lenses 6A and 6B are set above the arbitrary same pattern as a pattern on a photomask 1 so as to detect each pattern. In the inspection part 9, two signals are synchronized by a displacement amending circuit 10 and their patterns are compared by a comparison circuit 11. When the defective part is inspected, a control circuit 15 actuates an X-Y table 2 by a coordinates signal from an X-Y driving part 3 and a disaccord signal from the inspection part 9 so as to set the defective part in the central position of the corresponding objective lens 6A or 6B. Then the defective part is separated away from an optical path of a laser beam from a laser beam source 17, after which a shutter 18 is released to project the laser beam. The beam is polarized by a polarizing prism 16 and is projected to the defective part through the objective lens. In the defective part, the laser beam energy burns to break or form an amendment film thereby completing the amendment.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an apparatus for detecting and correcting pattern defects occurring in photomask patterns, etc., and particularly relates to a defect inspection and correction technique that can perform detection and correction fully automatically. [Background Art] The photolithography process, which is one of the manufacturing processes of semiconductor devices, requires a photomask on which element and circuit patterns are formed. In this photomask, a desired pattern is formed on a transparent substrate such as glass or quartz using a photolithography technique using a chromium film, but pattern defects occur during the manufacturing process. Such a pattern defect will cause a defect in the circuit pattern of one device formed on the wafer surface, so it must be detected and corrected.

As a method for inspecting and correcting this type of pattern defect, the photomask pattern is enlarged and displayed on a monitor TV or the like using optical and electrical means, and an operator visually inspects it!
A conceivable method is to irradiate the defective portion with a laser beam, and burn out the defective portion or form a correction film using the energy of the laser beam.

However, with this method, pattern defects cannot be corrected unless the operator memorizes and recognizes the entire correct shape of the pattern, and it is difficult to find the correct outline of the pattern at the defective portion. In particular, when a pattern defect is minute, it is easy to overlook, and when the defect extends over a wide area, it is difficult to confirm the outline. For this reason, inspection and correction require skill, and the correction work is extremely difficult and difficult, resulting in defective corrections and reduced product yield.

In addition, it is difficult to automate inspection and correction with this method.
The inventor has discovered that this is disadvantageous in terms of production efficiency and product cost.

[Purpose of the invention]

An object of the present invention is to provide a defect inspection and correction technique that can automate pattern defect inspection and correction, thereby improving product manufacturing efficiency and yield, and reducing costs.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, there is a detection section that independently detects two opposing patterns, an inspection section that compares the signals from each of these detection sections and inspects for defects based on the differences between the two, and a laser beam based on the signals from this inspection section. Special features include a correction unit that irradiates the defective area with rays of light, making it possible to fully automate the inspection of pattern defects and their correction, thereby improving product manufacturing efficiency and yield as well as reducing costs. It is something to do.

〔Example〕

FIG. 1 shows an embodiment in which the present invention is applied to a photomask defect inspection and correction apparatus. In the figure, 1 is a photomask as a sample for inspecting patterns and correcting defects.
A pattern of a light-shielding film such as a chromium film is formed on the surface of a substrate such as transparent glass or quartz, and in particular, in this example, a large number of identical minute patterns corresponding to semiconductor chips are formed in an array. This photomask 1 has an XY table 2
placed on top. This XY table 2 can be moved in the horizontal XY directions by an XY drive section 3, and has two tables 5 on the top that can be moved up and down by two drive sections 4.

Above the photomask 1 on the XY table 2 are two objective lenses 6A and 6B whose spacing can be changed as appropriate.
A pattern detection section 7 is provided. These objective lenses 6A and 6B respectively correspond to any two of the many identical patterns formed on the photomask 1, and each has a field of view of the portions facing each other, that is, the pattern portions that should be the same. And each objective lens 6A, 6B
The detected optical signal is converted into an electric signal by photoelectric elements 8A and 8B such as an industrial television camera or CCD, and sent to the inspection section 9. The inspection section 9 includes a deviation correction circuit 10, a comparison circuit 11, have. The deviation correction circuit 1o includes each of the photoelectric elements 8A, 8.
The amount of deviation between both patterns is determined by the signals from B and the XY drive section 3, and both signals are synchronized based on this amount of deviation. Comparison circuit 11 compares both synchronized signals and compares coincidence and mismatch between the two.Then, this coincidence/mismatch result is input to image processing circuit 12, where it is displayed as a pattern image on display 13. . As a result, correct pattern areas and defective areas are displayed on the display 13 in a manner that allows them to be distinguished from each other by black and white shading. In addition, in the case of a color display, correct pattern parts and defective parts are displayed in different colors.

- Masculinity A correction section 14A, 1413 is attached to each objective lens 5A, 6BK of the detection section. These correction parts 14A,
14B is a control circuit 15. Deflection prisms 16A, 16B,
Laser light source 17. Sha, Ri 18A, 18B, Aperture 19
A, 19B, and shutters 18A, 18 when necessary.
If B is selectively opened, the laser light from the laser light source 17 is deflected by the deflection prisms 16A and 16B to form the objective lens 6A.

6BK was introduced, and a 1 cm image of the surface of the photomask was obtained.

Note that the polarizing prism 16B is arranged so that it can be moved away from the optical path of the laser beam.

In the figure, 20 is an automatic focusing mechanism provided between the objective lenses 6A and 6B and the two tables 5.

Next, a method for inspecting and correcting pattern defects using the defect inspection and correction apparatus having the above configuration will be described.

First, the objective lenses 6A and 6B are set on arbitrary identical patterns on the photomask 1, and each pattern is detected. Each objective lens 6A.

The detected images 6B are converted into electrical signals by photoelectric elements 8A and 8B, respectively, and transferred to the inspection section 9. In the inspection section 9, the two signals are synchronized by the deviation correction circuit 10, and the patterns of the two are compared in the comparison circuit 11. This allows pattern matching.

A mismatch, that is, a match can be inspected for a correct pattern, and a mismatch can be inspected for a defective part. Then, the image processing area! 1) At step 12, an image as illustrated in FIG. 2 is displayed on the display 13 screen based on the match or mismatch. For example, by displaying the matching part Pa in gray and the non-matching part pb in black, the defective part (mismatching part) can be easily seen. Furthermore, if the images of both signals are displayed in different colors, for example, red and cyan, as shown in Fig. 113, the matching part Pc is white (red + cyan), the -mismatching part Pd,
Pe can be displayed in red and cyan. At this time, it can be seen that red is the defective part on one side and cyan is the defective part on the other side.

When the mismatched parts, that is, the defective parts are inspected in this way,
The control circuit 15 operates the XY table 2 using the coordinate signal from the XY drive fB3 and the discrepancy (defect) signal from the inspection section 9, and sets the defective part at the center position of the corresponding objective lens 6 or 6B. .

Now suppose that the defective part is facing six objective lenses. First, the polarizing prism 16B is moved sideways or upwards to move away from the optical path of the laser beam from the laser light source 17, and then the shutters 18A and 18B are opened. When the laser beam is irradiated, the laser beam passes through the polarizing prism 16A.
The light is polarized by the photomask 1 through the objective lens 6A.
Irradiation is applied to defects on the surface. At this time, the rectangular diaphragm 9At or 9B is adjusted according to the dimensions of the defective portion, and the laser beam is set in a shape that can encompass the defective portion.

Next, assume that a defective portion exists with respect to the objective lens 6B. At this time, the shutter 18A is closed and the shutter 18B is closed.
to open. Then, when the laser beam is irradiated, the laser beam is polarized by the polarizing prism 16BK, and is irradiated to the defective portion on the surface of the photomask 1 through the objective lens 6B. At this time, adjust the rectangular aperture and 9B according to the dimensions of the defective part,
The laser beam is set on a shape that can cover the defective part. As a result, the defective portion is burnt out or a correction film is formed by the laser beam energy, and the correction is completed.

In addition, the apertures 19A, 19B and shutter 18A mentioned above,
The operation of 18B can also be automatically controlled by the control circuit 15.

Note that when inspecting the inspection section 9, comparison may be made with a reference mask pattern, or the inspection signal data may be temporarily stored and corrected all at once after the inspection is completed.

〔effect〕

(1) A detection section that detects two patterns, an inspection section that compares the signals from this detection section and inspects for defects; Based on the results of this inspection section, a laser beam is irradiated to the defective part to detect the defect. Since it is equipped with a correction section for correction, pattern defects can be automatically inspected and automatically corrected.

(2) Since defects can be fully automatically inspected and corrected, product manufacturing efficiency and yield can be improved, and costs can be reduced.

(By attaching a display to the inspection section 33 and displaying the pattern in shading or color, the defective part can be clearly displayed, and the state of the defective part and the state of correction can be visually confirmed.

(4) Since a correction section is attached to each of the two pattern detection sections, one pattern can be inspected and corrected at the same time, and work and efficiency can be doubled.

+53 Since the beam size and irradiation time of the laser beam are automatically controlled, optimal defect correction can be performed at all times.

Although the invention made by the present inventor has been specifically described above based on examples, it goes without saying that the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. Nor. For example, the specific configuration of the detection section, the arrangement of the circuit configuration 5 correction section of the inspection section, etc. can be changed as desired.

In addition, two laser light sources are provided so that each laser light passes through the objective lenses 6A and 6B, respectively.
It may also be possible to correct defects in the objective lenses 6A and 6B at one time. Note that at this time, it is necessary to change the positions of the polarizing prism, shutter, aperture, etc. Furthermore, one of the laser light sources is used as a light source for removing defects where an extra light-shielding film is formed (sunspot defects).
Another unit may be used as a light source for correcting defects (white spot defects) caused by excess removal of the light-shielding film.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to a photomask pattern defect inspection and correction device, which is the background field of application, but the present invention is not limited to this. It can be applied to defect inspection and correction of formed photoresist films and other pattern inspection and correction. Furthermore, it is also possible to apply a technique for repairing the defective part using a laser.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of a display image, and FIG. 3 is an explanatory diagram of another display image. l...Photomask, 2...XY table, 3...
XY table drive unit, 6A, 6B...Objective lens, 7
...Detection section, 8A, 8B... Photoelectric element, 9... Inspection section. 13...Display, 14 people, 14B...Modification S
%15...Control circuit, 17...Laser light source, 18A
. 18B...Shutter, 19A, 19B...Aperture.

Claims (1)

[Claims] 1. A pattern detection section that independently detects the same parts of two patterns, an inspection section that compares the two signals from this detection section and inspects the mismatched portion as a defective section, and the signal of this inspection section. What is claimed is: 1. A defect inspection and repair apparatus comprising: a repair section that repairs a defective part by irradiating the defective part with a laser beam based on the above. 2. The detection section has independent objective lenses, and the correction section is equipped with an aperture, a shutter, and a laser light source corresponding to each of these objective lenses, so that laser light can be applied to each corresponding lens individually. A defect inspection and correction apparatus according to claim 1, comprising: 8. The defect inspection and correction apparatus according to claim gt or claim 2, comprising a display that displays images of the normal pattern and the defective part in dark and light shading or in different colors.