JPS63160036A - Defect display device - Google Patents

Abstract

PURPOSE:To display the position, size and shape of a defect by providing a defect detecting section, an arithmetic section, a storage section, an information processing section and a display section so as to find out an optional defect easily at a high speed. CONSTITUTION:A laser beam is collected from a laser generating source 31 of a defect detection section 3 movable on the surface of an object 1 to be measured fixed to a drive section 2. The reflected light of the collected laser light is led to a photodetector 34, where the light is subject to photoelectric conversion and a defect signal (a) corresponding to the change in the reflected luminous quantity is obtained by an amplifier 35. The signal (a) is given to a comparator 41 of an arithmetic section 4, where it is digitized while using a signal in excess of a reference value as a defect signal. A defect data signal (b) is obtained and a defect data based on the said signal (b) is stored in a storage section 5. Then an information processing section 6 reads the defect data, the size and shape of the defect are constituted as a picture and a picture signal (c) is outputted. The size and shape of the defect are displayed on a display section 7 from the signal (c).

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a defect display device, and particularly to a defect display device, which is used to detect defects formed on an information recording surface of an optical disk or a stamper, etc., at each stage of the optical disk manufacturing process. The present invention also relates to a defect display device that detects defects such as dust, or defects such as scratches or dust formed on the surface of a semiconductor wafer used in semiconductor manufacturing.

[Technological environment]

In recent years, defect display devices are required to detect defects such as minute scratches or dust scattered on the surface of the workpiece with high precision and high speed, and to accurately display the position, size, and shape of the defects. has been done.

[Conventional technology]

A conventional defect display device includes a high magnification microscope such as a scanning electron microscope, an object moving table such as an X-Y table, and a display section.

Next, a conventional defect display device will be explained with reference to the drawings.

As shown in FIG. 2, defects are captured within the field of view of a high-magnification microscope 9 such as a scanning electron microscope while moving and scanning a workpiece 1 fixed on a workpiece moving platform 8 such as an X-Y table. The size and shape of the defect are displayed on the display section 7.

[The problem that the invention attempts to solve]

The above-mentioned conventional defect display device randomly moves and scans the surface of the object to be measured using an object moving stage such as an X-Y table and displays defects from the surface using a high-magnification microscope. The drawback was that it required a great deal of time and skill to capture minute defects scattered throughout the area within the narrow field of view of a high-magnification microscope.

Furthermore, although it is possible to display defects as abnormalities in appearance, there is a drawback in that it is difficult to distinguish and display defects that exhibit specific optical changes that may affect the characteristics of the object to be measured.

[Failure to solve the problem]

The defect display device of the present invention includes an optical system that condenses and projects a laser beam onto the surface of an object to be measured, a defect detection unit that detects an optical change on the surface as a defect and outputs a defect signal, and a defect display unit that detects a defect based on the defect signal. a calculation unit that calculates the position and length of the defect and outputs a defect data signal; a storage unit that stores defect data based on the defect data signal; and a storage unit that stores the defect size and shape as an image based on the stored defect data. The apparatus includes an information processing section configured to output an image signal, and a display section that displays an image of the size and shape of the defect based on the image signal.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

The defect display device shown in FIG. 1 includes a drive section 2 for fixing and driving an object to be measured 1 and an optical system for condensing and projecting laser light onto the surface of the object to be measured 1, and detects optical changes in the surface. A defect detection section 3 that detects and photoelectrically converts it, and a calculation section 4 that computes the position and length of the defect based on the output signal from this defect detection section.
, a storage unit 5 for storing the calculation results, an information processing unit 6 for constructing an image of the position, size and shape of the defect from the stored calculation results, and a display unit 7 for displaying the information processing results as an image. Consists of.

Laser light is focused onto the surface of the object to be measured 1 fixed to the drive unit 2 through the laser source 31 of the movable defect detection unit 3 and the condenser lens 32 . The reflected light of the focused laser light is guided to a photodetector 34 by a beam splitter 33, photoelectrically converted, and then amplified by an amplifier 35 to obtain a defect signal a corresponding to a change in the amount of reflected light. The defect signal a and a preset reference value are compared by a comparator 41 in the calculation unit 4, and those exceeding the reference value are recognized as defects and set to 1, and those below the reference value are set to 0, and the defect signal a is digitized. do. By calculating the pulse width and pulse position of the obtained digital pulse by the pulse width counter 42 and pulse position detector 43, the length and position of the defect are determined and a defect data signal is output. The defect data based on the data is stored in the storage unit 5. The drive unit 2 and the movable defect detection unit 3 can scan the entire surface of the object to be measured 1 or a necessary measurement area, and store defect data of all defects within the scanning area in the storage unit 5. An information processing unit 6 such as a personal computer reads defect data of an arbitrary defect, constructs an image of the size and shape of the defect based on the defect data, and outputs an image signal C. The image signal C is used to display the size and shape of the defect on a display section 7 such as a CRT display. At this time, the information processing unit 6 displays the scanning area in the vicinity of an arbitrary defect two-dimensionally, and distinguishes between the color tone of the defective area and the color tone of areas other than the defective area. Displays the size and shape of defective parts with optical changes.

〔Effect of the invention〕

By adding a defect detection section, a calculation section, a storage section, an information processing section, and a display section, the defect display device of the present invention can easily and quickly find any defect and determine the location, size, and location of the defect.
This has the effect of displaying the shape.

In addition, it is possible to distinguish only areas that show optical changes exceeding a certain standard that affect the characteristics of the object to be measured, rather than just an abnormality in appearance, as defects, and to display the location, size, and shape of the defects, thereby identifying the type of defect. This has the effect of accurately determining the influence of the determined defect or defect on the characteristics of the object to be measured.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of the prior art. 1...Object to be measured, 2...Drive unit, 3.
...Defect detection unit, 31 ... Laser source, 32 ... Condensing lens, 33 ... Beam splitter, 34 ... Light detection Vessel, 35...
...Amplifier, 4...Arithmetic unit, 41...
- Comparator, 42...Pulse width counting! , 43...
...Pulse position detector, 5...Storage section, 6
... Information processing section, 7 ... Display section, 8.
...Measurement object moving table, 9...High magnification microscope, a...Defect signal, b...Defect data signal, C... image signal. 'X''It times foil Z diagram

Claims (1)

[Claims] an optical system that focuses and projects a laser beam onto the surface of the object to be measured; a defect detection section that detects an optical change in the surface as a defect and outputs a defect signal; and a defect detection section that detects the position and length of the defect based on the defect signal. a calculation unit that performs calculations and outputs a defect data signal;
a storage unit that stores the defect data signal; an information processing unit that configures an image of the size and shape of the defect based on the stored defect data signal and outputs an image signal; 1. A defect display device comprising: a display section that displays an image of size and shape.