JP2003130613A - Micro size measuring device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To stably and accurately perform a measuring operation in a minute dimension measuring device that measures a dimension of a measuring object based on image information output from an imaging device. SOLUTION: When a measuring device stores sample image information of an image of an object to be measured in accordance with pre-recorded measurement conditions in a storage device and measures the object to be measured based on the recorded measurement conditions, Of recorded image information corresponding to.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving the measurement efficiency of an apparatus for measuring a minute dimension on a semiconductor wafer or a mask for processing the semiconductor wafer.

[0002]

2. Description of the Related Art A block configuration example of a conventional minute dimension measuring apparatus will be described with reference to FIG. In this figure, an enlarged image of the sample 2 obtained by the optical microscope 1 is a TV camera 3 which is an imaging device using a two-dimensional sensor.
Then, a plurality of image frames are photoelectrically converted into image signals. The image signal is measured and controlled by a measurement control unit (PC: personal comput
er) 4 converts the digital image information into digital image information by the capture board 5 and the capture board 5
Store in the internal frame memory. Then, based on the contrast in the image information of one frame stored according to the image signal, the measurement control unit 4 obtains the dimension of the measurement point of the measurement object. At this time, the operator who operates this device, depending on the measurement point of the measurement object or the measurement object,
Various measurement conditions of this measuring device, for example, the speed of autofocus and its operating range, the operation mode of automatic light adjustment operation,
The measurement position in the image, the threshold level (threshold value) of the luminance contrast to be measured, etc. are set. When there are various setting items, a plurality of measurement recipes representing preset combinations of measurement conditions are recorded in the hard disk 6 which is a recording device. Then, from among the plurality of recorded measurement recipes, for example, about 10,000 kinds of measurement recipes, a measurement recipe that represents a combination of measurement conditions most suitable for the measurement is selected. Then, the measurement operation is performed after the measurement device is set according to the combination of the measurement conditions of the selected measurement recipe,
The optimum image is obtained for dimensional measurement. As described above, the image information captured by the microscope 1 and the TV camera 3 is transmitted via the capture board 5 or the capture board 5
And is reproduced and displayed in the camera image display area 9 on the monitor 7 via the hard disk 6 for recording the image information output from the capture board 5.

FIG. 2 shows an example of a measurement screen display including the above-mentioned image information on the screen of the monitor 7 according to the prior art. In this figure, in the map display area 8, a pass / fail judgment display is shown which indicates at which position on the wafer the measurement result is good or not when the wafer as the measurement object is scanned and imaged. There is. In this example, the line width pattern of the measurement position imaged by the TV camera 3 is displayed while moving the stage of the microscope 1 having the sample 2 which is a wafer.

In the camera image display area 9 shown in FIG. 2, image information based on a video signal picked up and output by the TV camera 3 in real time is displayed. A cursor line 10, 11, 12 used for dimension measurement is a figure 13 having a boundary which is the contrast of the measurement target.
Is displayed so as to sandwich it or to overlap the figure 13. Here, in the case of measuring an arbitrary position on the wafer, the stage of the microscope 1 is moved to a position where the line width pattern image of the designated portion is imaged by the operation of the operator. Then, as shown, the cursor lines 10, 1
After setting 1 and 12 to be displayed, desired dimension measurement is performed.

[0005]

The small dimension measuring apparatus using the above-mentioned conventional technique has a drawback that the operator is likely to make an erroneous measurement operation. That is, the measurement conditions described above
Select a predetermined measurement recipe from multiple types of measurement recipes, for example, 10,000 kinds of measurement recipes, each of which has a combination of (conditions related to auto focus, automatic light control, measurement position in image, slice level, etc.) Then
The line width of a specified location in the wafer to be measured is measured by the setting according to the selected measurement recipe. Here, there may be a large number of patterns having similar line widths and shapes around the designated portion, and the following problems may occur.

That is, (1) there is a high possibility that the operator erroneously selects a designated portion, and therefore there is a risk of measuring the line width of a portion that is not the object of measurement. (2) Even if the designated location is correctly selected, there is a high possibility that a measurement recipe whose measurement conditions do not match the designated location is selected. For example, the focus operation mode and the automatic adjustment automatic light adjustment operation mode are optimal. However, there is a possibility that the auto focus will not be in focus and the automatic light control will not be performed, and the dimension such as the line width cannot be accurately measured.

An object of the present invention is to eliminate the above-mentioned problems and enable stable and accurate measurement work.

[0008]

In order to solve the above problems, the present invention provides a microscope having a stage on which an object to be measured is placed, and an image pickup device for taking an enlarged image of the object to be measured magnified by the microscope. And a recording device for recording the measurement condition according to the measurement object, and based on the recorded measurement condition, measures the dimension of the measurement object based on the image information output from the imaging device. In a micro-dimension measuring device, image information obtained by imaging the measurement object according to the recorded measurement condition in advance is stored in the storage device, and the measurement object based on the recorded measurement condition. The recorded image information is displayed at the time of measuring.

Further, according to the present invention, various settings of the measuring device may be performed based on the recorded measurement conditions, and at least any one of the various settings may be changed and set.

Further, according to the present invention, the image information and the measurement condition may be simultaneously recorded in the recording device.

Therefore, according to the present invention, a combination of measurement conditions corresponding to each measurement recipe is prepared in advance for each measurement recipe.
A sample image of the designated portion is captured and the image is registered. By doing so, at the same time when the measurement recipe is selected, a registered image display area is provided on the side of the camera image display area so that the registered sample image can be displayed. Therefore, by looking at the sample image, the operator can always check the image being measured while comparing it with the sample image. Since the measurement work is performed with such a confirmation operation, it is possible to prevent the line width that is not the designated portion from being measured by mistake. In addition, by registering an image that is automatically adjusted at the in-focus position, it is possible to determine whether or not the measurement conditions in the measurement recipe being used are correct.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a conventional minute dimension measuring apparatus, and the configuration of the minute dimension measuring apparatus shown in this figure is similarly used for realizing the present invention. Here, in the block configuration of the small dimension measuring apparatus shown in this figure, the operation different from the operation described in the related art is that a selected recipe among a plurality of measurement recipes recorded in the hard disk 6 in advance is selected. The measurement target location of the corresponding measurement target is imaged with the combination of the measurement conditions of the measurement recipe. At the same time, the sample image information obtained by imaging is stored in the hard disk 6 in association with the measurement recipe, and when the same measurement object is measured again based on the recorded and selected measurement conditions, The recorded sample image information is displayed while being associated with the measurement conditions.

Further, an embodiment of the present invention will be described with reference to FIG. 3 showing a display example of a measurement screen according to the present invention. (1) Registration of Sample Image First, sample image information associated with each of the plurality of measurement recipes recorded in the hard disk 6 as described above is recorded in the hard disk 6. That is, the combination of the measurement condition corresponding to a certain measurement object and the sample image under the condition is determined. In that case, when the measuring device measures the measuring object under the determined measuring condition, the image signal of the measuring object obtained by imaging with the TV camera 3 is stored in the frame memory of the capture board 5. At the same time, the image information based on the stored image signal of the measurement target is used as sample image information to connect the image registration button 14 displayed on the measurement screen of FIG. 3 to a predetermined operation method (for example, to the measurement control unit 4). If a mouse input device (not shown) is used to move the cursor to the image registration button 14 and then click the click button of the mouse input device), the frame memory of the capture board 5 is replaced with the hard disk 6 And the image information is recorded on the hard disk 6. As described above, image registration is performed by registering image information for each measurement recipe, that is, recording sample image information corresponding to each measurement recipe.

(2) Manual measurement After image registration is performed as described above, a manual selection operation is performed, for example, by using a measurement recipe for manual measurement and an operation using the above-described operation method. The case will be described. First, an optimum function function among the functions A to H is selected according to the type of the measurement object, and the parameter No. 1-No. Optimal parameters are selected from 50. Here, the function is a function classification classified according to the type of the horizontal or vertical luminance waveform of the image signal of the measurement target. The brightness waveform is roughly classified into, for example, a brightness waveform of transmitted light and a brightness waveform of reflected light. The types of parameters include, for example, edge detection method selection, slice level setting, noise level setting, measurement line processing method selection, and histogram width setting. Now, for example, [parameter No. of function A. 20], the sample image information recorded in accordance with the selected measurement recipe is displayed on the screen of the monitor 7 in the registered image display area shown in FIG. It is displayed as 16. As the image information displayed in the registered image display area 16, sample image information according to the newly selected measurement recipe is displayed every time the measurement recipe is switched.

FIG. 4 is a flow chart showing an example of a procedure for registering a sample image and manual measurement according to the present invention. Figure 4
4A shows a procedure for registering a sample image, and FIG. 4B shows a procedure for manual measurement. In FIG. 4A, first, a measurement recipe is selected (step 100). Next, it is determined whether the image registration button 14 has been pressed (step 10).
1). If not (No), the registration ends. If the image registration button 14 is pressed (Yes), the measurement target location of the measurement target corresponding to the selected recipe is imaged with the combination of the measurement conditions of the measurement recipe (step 102). Next, the sample image information associated with the measurement recipe is recorded in the hard disk 6 (step 103). Further, in FIG. 4B, the function function and the parameter are selected, that is,
A measurement recipe is selected (step 200). Next, the sample image information recorded according to the selected measurement recipe is displayed on the screen of the monitor 7 in the registered image display area 16 shown in FIG. 3 (step 201). Next, the operator inputs the image information of the camera image display area 9 and the registered image display area 16
The sample image information is compared with the sample image information (step 202). As a result of the comparison, it is determined whether or not they are substantially the same (step 203). If they are not the same (in the case of No), the measurement is ended. If they are the same (Yes), the operator measures the dimensions (step 204). By doing so, when a measurement recipe is selected and a combination of the selected measurement conditions is used to cause the measurement device to perform measurement, it is recorded in advance according to the measurement recipe that is a combination of predetermined measurement conditions, and , The displayed sample image information in the registered image display area 16 and the image information in the camera image display area 9 displaying the image information based on the image signal currently captured by the TV camera 3 for measurement. , The operator can compare. So, for example,
If the image information is almost the same, it can be confirmed that the correct measurement recipe is selected. Therefore, the operator is less likely to perform dimension measurement using the wrong combination of measurement conditions, and can confirm that the optimal measurement recipe is correctly centered on the measurement object more efficiently. It is possible to eliminate the need to make a separate measurement.

If "Registered image display" is selected in the registered image display field 15 during measurement, the sample image information registered above is displayed, and if "Enlarged image display" is selected, Image information obtained by enlarging the registered sample image information is displayed. Further, the quality judgment display of the map display area 8 described in the related art may be displayed simultaneously with the image information and the sample image information of the camera image display area 9 of the present invention.

[0017]

As described above, according to the present invention, prerecorded sample image information is displayed in accordance with a measurement recipe which is a sample according to a measurement recipe that is a combination of measurement conditions. Therefore, the operator can perform the measurement work while comparing the image information display as the sample with the image information display based on the image signal output from the TV camera during image pickup. Therefore, as a result of the comparison, for example, when the selection of the measurement recipe is erroneous for the measurement object, the display of the registered image display area 16 and the display of the camera image display area 9 are mutually performed as shown in FIG. It can be immediately recognized that the measurement points are different, and it can be seen that the measurement points are erroneous. Therefore, it is possible to avoid as much as possible an operation error such that the operator acquires the measurement data without noticing that the measurement is erroneous.

[Brief description of drawings]

FIG. 1 is a diagram showing a block configuration example of a minute dimension measuring device.

FIG. 2 is a diagram showing an example of a measurement screen display on a monitor 7 according to a conventional technique.

FIG. 3 is a diagram showing a display example of a measurement screen according to the present invention.

FIG. 4 is a flowchart showing an example of a procedure of registering a sample image and manually measuring according to the present invention.

[Explanation of symbols]

1: Optical microscope, 2: Sample (measurement object), 3: T
V camera, 4: measurement control unit (PC), 5: capture board, 6: hard disk, 7: monitor, 8:
Map display area, 9: Camera image display area, 1
0: Left vertical cursor line that serves as a reference for measuring position,
11: Right vertical cursor line that serves as a reference for specifying the measurement position,
12: Horizontal cursor line that serves as a reference for measuring position,
13: contrast figure, 14: image registration button,
15: Registered image display column, 16: Registered image display area.

Continued front page    F term (reference) 2F064 AA01 DD08 DD09 HH03 HH05                       HH08 MM11 MM22 MM26 MM37                       MM45 MM50                 2F065 AA01 AA21 BB02 BB03 BB18                       CC17 DD19 FF01 FF04 FF27                       FF61 FF67 JJ03 JJ26 PP12                       PP24 QQ24 QQ25 QQ28 QQ31                       RR09                 4M106 AA01 BA10 CA50 DH60

Claims (3)

[Claims] 1. A microscope having a stage on which an object to be measured is placed, an imaging device for taking an enlarged image of the object to be measured magnified by the microscope, and a recording device for recording measurement conditions according to the object to be measured. And a micro-dimension measuring device that measures the dimensions of the measurement object based on image information output from the imaging device based on the recorded measurement conditions, in accordance with the recorded measurement conditions in advance. And storing the sample image information obtained by imaging the measurement object in the storage device, and displaying the recorded sample image information when measuring the measurement object based on the recorded measurement conditions. A minute dimension measuring device characterized by performing. 2. The small dimension measuring device according to claim 1, wherein various settings of the measuring device are performed based on the recorded measurement conditions, and at least any one of the various settings is further changed. A minute dimension measuring device characterized by being settable. 3. The minute dimension measuring apparatus according to claim 1 or 2, wherein the sample image information and the measuring condition are recorded in the recording apparatus at the same time.