JPH04337235A - Scanning type electron microscope - Google Patents

Abstract

PURPOSE:To improve the work efficiency by extracting the image information, comparing it with the reference image information, judging the quality, and generating an alarm. CONSTITUTION:An electron beam is scanned on a sample 8 which is a semiconductor substrate, secondary electrons are extracted and drawn on a display 10, and the image information is stored in an image memory section 3. The memory section 3 feeds the image information to a comparison section 4 in sequence, it is compared with the reference information signal allowing the contrast, and the quality is judged. If the quality is satisfactory, the comparison section 4 erases the image information, if the quality is unsatisfactory, a signal is generated, and an alarm section outputs an alarm. Inspection can be performed without invariably monitoring the image on the display 10, and the work efficiency can be improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning electron microscope that scans a pattern on a semiconductor substrate with electrons and captures generated secondary electrons for observation and measurement of pattern dimensions.

0002

2. Description of the Related Art Conventionally, although not shown in the drawings, this type of scanning microscope has been equipped with an electron gun that generates electrons, a deflection scanning section that scans the generated electrons onto a semiconductor substrate, and an electron gun that generates electrons from the semiconductor substrate. A secondary electron detector that captures secondary electrons, an image processing section that inputs and processes the output of the secondary electron detector, an arithmetic processing section that processes the output of the image processing section, and an arithmetic processing section. It also has a display that draws a pattern on the semiconductor substrate using the output.

[0003] When inspecting a pattern on a semiconductor substrate using a scanning electron microscope, the semiconductor substrate is placed on a stage, and at present, electrons are almost automatically scanned onto the semiconductor substrate and a pattern is drawn on a display. , and automatically compared it with standard drawings to check whether it was good or bad.

0004

[Problem to be Solved by the Invention] However, electrons are often accumulated in the semiconductor substrate, and the electrons that are scanned are
When the electrons react with the accumulated electrons, the screen displayed on the display becomes whitish or dark, resulting in a lack of contrast, which may make inspection impossible. For this reason, the display is constantly viewed and the device is stopped when a screen defect occurs. Therefore, there is a problem that one person cannot handle multiple machines, and even though it is automated, there is a drawback that work efficiency is low.

[0005] An object of the present invention is to provide a scanning electron microscope that solves these problems and has good working efficiency.

[0006]

[Means for Solving the Problems] The scanning electron microscope of the present invention includes: an image storage unit that stores an image signal obtained from secondary electrons; a comparison unit that compares the stored image signal with a reference image signal; It also includes an alarm section that issues an alarm based on the output of the comparison section.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram schematically showing an embodiment of a scanning microscope according to the present invention. As shown in the figure, this scanning microscope has an image storage section 3 that stores output signals of an image processing section 3, and sequentially extracts information signals stored in the image storage section 3 to create a brightness/saturation pattern. This is achieved by providing a comparison section 4 that compares the signal with an acceptable reference signal, and an alarm section 5 that issues an alarm based on the determination made by the comparison section 4. Other than that, it is the same as before. Next, the operation of this scanning microscope will be explained. First, as explained in the conventional example, an electron beam is scanned on the sample 8 which is a semiconductor substrate, secondary electrons are captured, and the display 1
0, and the drawing information is stored in the image storage unit 3. The image storage section 3 sequentially sends the drawing information to the comparison section 4. The comparison section compares the brightness (contrast) with a standard information signal that allows for the comparison and determines whether it is good or bad. If it is good, the comparison section erases the drawing information, and if it is not, it outputs a signal, and the alarm section 5 generates an alarm. The operator hears this alarm and stops the equipment.

[0009]

[Effects of the Invention] As explained above, the present invention includes means for extracting image information and comparing it with reference image information to determine whether the image information is good or bad, and means for generating an alarm if the image information is not good. This has the effect of providing a highly efficient scanning electron microscope that can perform inspections without constantly monitoring display images.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a scanning microscope showing one embodiment of the present invention.

[Explanation of symbols]

1 Electron gun 2 Secondary electron detector 3 Image storage section 4 Comparison section 5 Alarm section 6 Image processing section 7 Arithmetic processing unit 8 Sample 9 Deflection scanning section 10 Display

Claims (1)

[Claims] 1. A scanning electron microscope that deflects and scans electrons onto a surface of a sample to be measured, detects generated secondary electrons, and images the surface of the sample to be measured, wherein an image signal obtained from the secondary electrons is stored. 1. A scanning electron microscope comprising: an image storage section that compares a stored image signal with a reference image signal; and an alarm section that issues an alarm based on the output of the comparison section.