JP2008122097A - Inspection measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection measuring device capable of continuing observation efficiently with a high-power objective lens as it is, by dispensing with operation wherein, in an inspection device using a microscope, it is determined whether an object is within a visual field of the high-power objective lens at every time when changing the object, and when being out of the visual field, switching to a low-power objective lens is performed again, and a pattern position is confirmed, and then switching to the high-power objective lens is performed. <P>SOLUTION: A pattern is photographed beforehand by the low-power objective lens, and its image and its coordinate position are registered. When observing by the high-power objective lens, the registered low-power image and a visual field domain 31 of the high-power objective lens are displayed on a low-power image screen 32. When the visual field domain of the low-power image is moved by a mouse, a stage is controlled sequentially, and an objective pattern can be positioned easily within a high-power objective lens visual field, to thereby dispense with switching to the low-power objective lens. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an inspection / measurement apparatus, and more particularly to stage control suitable for medical / industrial inspection / measurement apparatuses.

  One application example of the inspection and measurement apparatus is a line width measurement apparatus. The line width measuring device is a device that mainly measures a mask pattern width of a semiconductor TFT (Thin Film Transistor). The line width measuring device includes a microscope, a light source, a camera attached to the microscope, a monitor that displays a camera image, a stage that is a sample stage on which a subject is placed, and an XY movement that moves the stage in the XY direction within a horizontal plane. A mechanism, a Z movement mechanism that moves up and down in the Z direction perpendicular to the horizontal plane, and a PC (personal computer) that controls these movement mechanisms in the XYZ directions.

  Conventionally, in a line width measuring apparatus, a screen displayed on a monitor by a PC application software includes a live image screen using a high-magnification objective lens and a plurality of movement buttons for instructing each movement direction of the XY stage and the Z stage. It was an XYZ stage control screen. The operator can move the XY stage in a desired direction by pressing a movement button displayed on the XYZ stage control screen with a mouse or the like.

  In the line width measuring apparatus having such a configuration, for example, when observing a pattern continuously generated on a wafer with a high magnification objective lens, the subject is observed and measured in the following flow. I was going.

  First, the objective lens of the microscope is switched to a low-magnification objective lens, and the live image screen displayed on the monitor screen is observed. If the pattern can be confirmed, the operator checks the monitor screen while viewing the XYZ stage control screen. Operate the move button to move the stage. After moving the pattern to the center of the image, change the objective lens of the microscope from the low-magnification objective lens to the high-magnification objective lens, and press the move button on the XYZ stage control screen in the same way as when switching to the low-magnification objective lens. After the operation, the XY stage was moved so that the pattern was at the center position of the image, and then the pattern was observed and inspected and measured. Next, when the operator observes another pattern, first, it is determined whether or not it is within the field of view of the high-magnification objective lens. Operate the move button on the screen to move the stage and observe the pattern. If it is out of the field of view, the operator switches the objective lens to the low magnification objective lens again, observes the image displayed on the monitor screen, and if the pattern can be confirmed, switches to the high magnification objective lens. The pattern was measured and inspected.

  As this type of inspection and measurement apparatus, for example, in the process of creating inspection data in Patent Document 1, an overview inspection apparatus that automates the transition from macro observation to micro observation and simplifies the coordinate input of the defect portion. Patent Document 2 proposes an inspection data setting method capable of setting image processing parameters without requiring input of position coordinate data, and an inspection apparatus using the method.

JP 2000-35319 A JP 2005-30966 A

  According to the prior art described above, when observing a pattern of a subject to be measured with a high-magnification objective lens, the pattern is first confirmed by changing to a low-magnification objective lens, widening the field of view, and then the stage. Is moved to the center position of the image and then changed to a high magnification objective lens. For this reason, when observing another pattern, it is determined whether it is within the field of view of the high-magnification objective lens. After confirming the center position, it is necessary to repeat the determination and operation of changing to the high magnification objective lens every time the subject is changed, and the work efficiency is poor.

  Further, in Patent Documents 1 and 2, when switching from a low-magnification objective lens to a high-magnification objective lens, even if the target subject is out of the field of view of the high-magnification objective lens, the low-magnification objective lens is not switched. The problem of continuing observation with a high-magnification objective lens is not taken into consideration.

  Therefore, the object of the present invention is to determine whether or not the subject is in the field of view every time the subject is changed, and when it is out of the field of view, an operation of switching between the low magnification objective lens and the high magnification objective lens again is not necessary. An object of the present invention is to provide an inspection / measuring apparatus that can perform observation with the high magnification objective lens efficiently.

In order to solve the above problems, an inspection and measurement apparatus according to the present invention includes an XY stage, an XY movement mechanism that moves the XY stage in the XY direction, a Z stage movement mechanism that moves the XY stage in the Z direction, A microscope having a low-magnification objective lens and a high-magnification objective lens, a camera attached to the microscope, a computer to which a video signal of a subject generated by the camera is input, and a video signal of the subject input to the computer In an inspection and measurement apparatus comprising at least a monitor that displays the image of
The image of the subject photographed with the low-magnification objective lens of the microscope and its coordinate position are registered in advance, and when observing the pattern of the subject with the high-magnification objective lens, on the monitor screen, In addition to displaying the registered image, the field of view by the high-magnification objective lens is displayed, and the computer interlocks with the movement operation by the pointing device with respect to the displayed field of view, and the XY stage moving mechanism and the Z It has a function of controlling the stage moving mechanism.

  According to the present invention, when observing a subject pattern with a high-magnification objective lens, the subject pattern is once photographed with a low-magnification objective lens, and its image and coordinate position are registered in advance. As a result, when observing a pattern in the field of view of the low-magnification objective lens, the field of view is narrowed by changing to the high-magnification objective lens, and even if the observed pattern is not visible, the pre-saved low-magnification image data is shown. The XY stage is moved to the coordinate position of the visual field by the control of the PC 50 simply by selecting the selected position with a mouse or the like. When the viewing area is moved by operating the mouse or the like on the low-magnification image display screen, the movement of the XY stage is controlled in conjunction with the movement of the mouse, so that it can be easily moved to a position having a target pattern.

  Therefore, it is not necessary to switch to the low magnification objective lens every time the subject is changed, and inspection and measurement can be performed efficiently.

  An embodiment according to the present invention will be described in detail below with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a configuration of a line width measuring apparatus according to the present invention. Usually, the line width measuring device is mainly an XY stage 45, a Z moving mechanism 44, an X moving mechanism 42, a Y moving mechanism 43, a camera 40, a light source 46, a microscope 41, and an AF device for automatically focusing on the subject of the microscope. 52, a PC (personal computer) 50, and a monitor 51.

  The XY stage 45 is a sample stage on which a subject is placed. The X movement mechanism 42 and the Y movement mechanism 43 perform horizontal position control, and the Z movement mechanism 44 performs vertical position control. The X moving mechanism 42, the Y moving mechanism 43, and the Z moving mechanism 44 are driven by controlling the X driver 47, the Y driver 48, and the Z driver 49 by application software of the PC 50, respectively. A subject image is input from the microscope 41 to the camera 40. The camera 40 generates a video signal and inputs this signal to the PC 50. The application software of the PC 50 displays these videos on the monitor 51.

  FIG. 2 is a diagram showing a display screen of the present embodiment by the application software of the PC 50. The monitor 51 includes a live image screen 30 that displays a live image of a high-magnification image, a low-magnification image that is captured and registered in advance with a low-magnification objective lens, and a low-magnification image screen 32 that indicates a field-of-view area number, An XYZ stage control screen 33 showing a control button for controlling movement of the XY stage in the XY direction and the Z movement direction, and a schematic diagram screen 37 showing a schematic diagram of the wafer are displayed.

  The block arrow on the XYZ stage control screen 33 is a button. When this button is pressed with a pointing device such as a mouse, the X driver, Y driver, and Z driver are controlled by the application software of the PC 50. The XY stage button 35 moves in the + X direction, -X direction, + Y direction, and -Y direction, and the Z stage button 34 moves in the + Z direction and -Z direction, respectively.

  A circular pattern 36 on the schematic diagram screen 37 schematically shows the wafer. A field of view area 31 on the low-magnification image screen 32 indicates the current field of view of the objective lens.

  The schematic diagram screen 37 is divided into twelve squares in a lattice shape, and here, the reference numbers P1 to P12 are given respectively. This indicates that the wafer can be divided into 12 fields of view with a low magnification objective lens. Further, the twelve cells P1 to P12 have button functions, and when the cells are pressed, the cells move to a predetermined coordinate position of the registered image corresponding to the cells and display the registered image on the low-magnification image screen 32. . The coordinates of the cells can be determined uniquely because the wafer size is known.

In addition, if the number of imaging elements in the horizontal direction and the vertical direction is known, the size per pixel of the objective lens can be determined in advance for an image of one field of view. Therefore, as shown in FIG. 3, for example, when obtaining the coordinates (X, Y) of the hatched pixel 61 in one visual field 60, the size of one pixel, that is, dx and dy are known. Therefore, if the visual field coordinates (X0, Y0) that are the coordinates of the visual field area can be determined, the following expression is obtained.
X = X0 + 5dx
Y = Y0 + 5dy
That is, the coordinates of an arbitrary pixel position in this image can be calculated.
The case of observing a pattern continuously generated on a wafer with a high-magnification objective lens will be described with reference to FIG.

First, the images for the fields of view P1 to P12 on the schematic diagram screen 37 are taken and registered with the low magnification lens.
In step 1, the operator changes the objective lens of the microscope 41 to a low magnification objective lens.
Next, in step 2, the operator presses the grid on the schematic diagram screen 37, and the PC 50 controls the X movement mechanism 42, the Y movement mechanism 43, and the Z movement mechanism 44, and the XY stage 45 moves in the XYZ directions. Move to the coordinate position for the visual fields P1 to P12.
In step 3, the operator takes an image of the location. After adjusting the coordinate position on the XYZ stage control screen 33, in step 4, the coordinate is registered as the coordinate of the visual field. The coordinate-registered image and coordinate position data are not shown, but may be stored in an external storage device of a peripheral device such as a hard disk connected to the PC 50. Is the operator all done? In the determination step 5, it is determined whether or not the images for the visual fields P1 to P12 and the coordinate registration are completed. If not, the process returns to the XYZ movement in step 2.

  Next, when the image and coordinate registration for the fields of view P1 to P12 are completed, the objective lens of the microscope is changed to a high-magnification objective lens in Step 6.

  In step 7, the operator selects field numbers from the field of view P <b> 1 to P <b> 12 on the field-of-view position designation schematic diagram screen 37. The area indicating the field number on the schematic diagram screen 37 is a button. When the operator presses the field number button, in step 8, the PC 50 controls the X movement mechanism 42, the Y movement mechanism 43, and the Z movement mechanism 44, and the XY stage moves to the coordinate position of the field number. . In step 9, the image registered in the coordinate registration in step 4 is displayed. In the low-magnification image screen 32 of FIG. 2, a case where the visual field P5 is pressed is shown as an example. A live image by the high-magnification objective lens in the visual field region 31 is displayed on the image screen 30 of the high-magnification image screen (live). Yes.

  Next, the operator moves the visual field region 31 of the low-magnification image 32 with a pointing device such as a mouse in the visual field frame movement in step 10. The application software of the PC 50 moves the stage by controlling the X driver 47, the Y driver 48, and the Z driver 49 in the XYZ movement of step 11 by the amount of movement of the visual field region 31. In step 12, the operator can observe the target pattern on the live image screen 30.

  Next, when observing another pattern with the high magnification objective lens, the operator determines whether or not the pattern is displayed on the low magnification image screen 32 in step 13. Move. If it is out of the field of view, the process proceeds to the field position designation step 7 and a field of view with a pattern is selected from the fields of view P1 to P12 of the schematic diagram screen 37.

  As described above, the position of the image of the low-magnification objective lens registered on the schematic diagram 37 showing the entire wafer is indicated by the field frame 31 of the low-magnification objective lens. By simply selecting the image of the low magnification objective lens with a pointing device or the like, the image can be easily switched, and the XY stage is controlled in conjunction with the movement operation of the visual field region 31 of the low magnification image 32 with a mouse or the like. The target pattern can be easily moved within the field of view of the high-magnification objective lens. Therefore, it is not necessary to switch to the low magnification objective lens every time the subject is changed.

  The preferred embodiment has been described above, but various modifications can be made without departing from the spirit of the present invention.

The figure which shows the structure of the test | inspection measuring device which concerns on this invention. The figure which shows the display screen of the test | inspection measuring apparatus which concerns on this invention. The figure explaining the coordinate calculation of a pixel position. The observation flowchart with the high magnification objective lens in the test | inspection measuring apparatus of this invention.

Explanation of symbols

  30 ... Live image screen, 31 ... Field of view of objective lens, 32 ... Low magnification image screen, 40 ... Camera, 41 ... Microscope, 33 ... XYZ stage control screen, 34 ... Z stage button, 35 ... XY stage button, 42 ... X moving mechanism, 43 ... Y moving mechanism, 44 ... Z moving mechanism, 45 ... XY stage, 46 ... light source, 47 ... X driver, 48 ... Y driver, 49 ... Z driver, 50 ... PC (personal computer), 51 ... Monitor, P1 to P12 ... Field of view.

Claims (1)

XY stage,
An XY moving mechanism for moving the XY stage in the XY direction;
A Z stage moving mechanism for moving the XY stage in the Z direction;
A microscope having a low magnification objective lens and a high magnification objective lens;
A camera attached to the microscope;
A computer to which a video signal of a subject generated by the camera is input;
In an inspection and measurement apparatus comprising at least a monitor that displays an image of a video signal of the subject input to the computer,
An image of a subject photographed with the low-magnification objective lens of the microscope and its coordinate position are registered in advance, and when the pattern of the subject is observed with the high-magnification objective lens, the registration is displayed on the monitor screen. And the computer displays the field area by the high-magnification objective lens, and the computer operates in conjunction with the movement operation by the pointing device with respect to the displayed field area, and moves the XY stage moving mechanism and the Z stage. An inspection and measurement apparatus having a function of controlling a moving mechanism.

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