JP3333148B2 - Appearance inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection apparatus used for visual inspection of an object such as a wafer or a liquid crystal glass substrate, and more particularly, to a macro observation system and a micro observation system which are arranged on the same stage. The present invention relates to a visual inspection device capable of switching from an observation system to a micro observation system.

[0002]

2. Description of the Related Art In a process of manufacturing a wafer, a liquid crystal glass substrate and the like, the presence or absence of a defect on a substrate is inspected in each film forming step, pattern baking step and etching step. For example,
In the inspection of a liquid crystal TFT substrate, a macro observation is performed for each process to detect a defect on the substrate, and if a defect is found on the substrate, a mark is made on the defective portion. Next, the defect found by the macro observation was inspected in detail by micro observation with a microscope.

However, the macro observation and the micro observation are individually performed on independent stages, and in the micro observation, a defect (mark) on the substrate is visually observed by relying on the mark made by the macro observation. Must be positioned at the optical axis position of the objective lens provided in the micro observation system, and the operation is extremely complicated.

[0004]

SUMMARY OF THE INVENTION In the above technical background, the present applicant disclosed in Japanese Patent Application No. 4-132577, a macro observation system and a micro observation system arranged on the same stage, and the macro observation system was discovered by macro observation. We have proposed an appearance inspection device that can easily move the defective part below the optical axis of the micro observation system.

As shown in FIG. 13, such an apparatus comprises an apparatus body 1, a stage 2 movably attached to the apparatus body 1 in the X and Y directions, and a stage 2 held by the apparatus body 1.
, A micro observation system 4 held by the apparatus main body 1 and arranged above the stage 2 adjacent to the macro observation system 3, and between the macro observation system 3 and the micro observation system 4 And a coordinate display device 5 for displaying the relative coordinates of.

In such a device, the defective portions found in the macro observation system 3 are sequentially arranged at the spot illumination position S of the spot illumination device 6, and each time the foot switch 7 is used.
Is pressed to input coordinates to the coordinate display device 5. When moving the defective part to the micro observation system, the stage 2 is moved to the micro observation system while the substrate is placed on the stage 2, and the stage 2 is moved so that the relative coordinates displayed on the coordinate display device 5 become zero. By doing so, the defective portion can be made to coincide with the optical axis position of the objective lens 8.

[0007] However, the above-described appearance inspection apparatus is
In order to input the coordinates of the defect found on the substrate, the defect must be placed at the spot illumination position S. In reality, it is necessary to move the large stage 2 to overlap the defective portion on the spot dropped on the substrate. Such a work requires a fine adjustment of the large stage 2 and places a great burden on the observer.

In the operation of superimposing the defective portion on the spot dropped on the substrate, a defect is searched for in such a posture as to cover the substrate on the stage 2, so that dust may fall from the operator onto the substrate. There is a problem that is high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can automate the transition from macro observation to micro observation, and can reduce the number of stage operations when inputting coordinates of a defect. It is an object of the present invention to provide a visual inspection apparatus capable of reducing the possibility of dust falling from an operator onto a substrate and acquiring data necessary for quality control of a process such as classification and number of defects.

[0010]

In order to achieve the above-mentioned object, the present invention provides a method for controlling the distance between a macro observation region and a micro observation region.
A movable motorized stage and a macro observation system that is arranged in a macro observation area and forms an object image through a low-magnification lens on the object mounted on the electric stage , and is arranged in a micro observation area, A micro observation system for forming an image of a subject mounted on a motorized stage through a high-magnification lens , and a macro image input unit for converting the subject image formed by the macro observation system into an image signal Display means for displaying the subject image converted by the macro image input means; designation means for designating a target area of the subject image on a display screen of the display means; The coordinate position is converted to the coordinate position of the motorized stage and stored in the storage means, and has already been input to the target part displayed on the display means.
Subjected Mino mark, and the attention area based on the coordinate position data of the target site that was read from the storage means has a control means for controlling the electric stage to move the optical axis position of the micro observation system A visual inspection device characterized by
You.

[0011] The present invention also relates to the above visual inspection apparatus.
The control means performs a plurality of observations of the subject in a matrix.
The observation area is divided into macro observation system macros.
(B) Move the motorized stage so that it is sequentially brought into the observation area
Control.

The present invention also relates to the above-mentioned appearance inspection apparatus.
The control means sets the center coordinates of each observation area in advance.
The observation area displayed on the display means and other observation areas
Calculate the movement amount of the motorized stage from the center coordinates of the rear
The center of the observation area is coincident with the optical axis of the macro observation system.
Control of the movement of the electric stage.

[0013] The present invention also relates to the above visual inspection apparatus.
And the control means includes an observation area displayed on the display means.
A frame indicating the observation area is superimposed on the macro observation image of
Adjacent observations that are shown and outside the frame
Marks already entered for the region of interest already specified in the area
Mark.

[0014]

Embodiments of the present invention will be described below.

FIG. 1 shows the functional configuration of an appearance inspection apparatus according to an embodiment of the present invention, and FIG. 2 shows the appearance of the apparatus.

In the visual inspection apparatus of the present embodiment, a pair of guide rails 12 are provided on the upper end surface of a microscope base 11 in the Y direction, and a Y stage 13 is slidably mounted on the guide rails 12. It is placed. A central portion of the Y stage 13 is opened in a square shape, and a pair of guide rails 14 is arranged in the X direction with the opening interposed therebetween. An X stage 15 is mounted on the guide rail 14 so as to be movable in the X direction. Hereinafter, Y stage 14, X stage 1
5 is referred to as an XY stage. A portal arm 16 fixed to the microscope base 11 is provided above the XY stage. The moving area above the X stage 15, the macro observation system 17 held by the arm 16 is arranged on the right side along the X direction, micro observation system held by the arm 16 to the left side along the X direction 18 Is arranged.

The macro observation system 17 has a wide field of view and a low magnification (1.
(Approximately / 40 to 1/5) of a TV lens 21 and a macro TV camera 22 for converting a substrate image captured through the TV lens 21 into a TV signal. In addition,
The macro observation system 17 includes a macro observation area centered on the observation optical axis.
Macro illumination device 19 for macro illumination of S is on the right side of the mounting table
It is located at the back.

The micro observation system 18, micro illumination device 23 for illuminating the microscopic observation region to the central observation optical axis (the objective optical axis), the microscope comprising an objective lens 24 and an eyepiece lens 25 and the like, taken from the objective lens 2 4 A micro TV camera 27 that projects the defective image onto a light receiving surface via a TV camera lens 26 and converts it into a TV signal.

As shown in FIG.
Motor 31 serving as a power source for moving the Y stage
It has. When the computer 32 gives a command to the controller 33, the controller 33 controls the driving amount of the motor 31 via the driver 34.

A scale 35 is provided on the side surface of the XY stage.
Is read and output to the scale counter 37. The count value of the scale counter 37 is input to the computer 32 via the controller 33.

Each TV signal from the macro TV camera 22 and the micro TV camera 27 is input to a switch 38. The switch 38 selects one of the TV signals in accordance with a switch signal provided from the computer 32 and selects one of the TV signals.
Send to 9

The computer 32 is connected with a mouse 41 constituting a part of the coordinate designating means, and a mouse mark is displayed on the screen of the display device 39 by the image processing circuit 42. In the present embodiment, the term “coordinate” refers to a position from an origin set in advance for the XY stage.

The mouse 41 has an input button 41a for instructing coordinate input and a cancel button 4 for canceling the input coordinates.
1b. Further, a floppy disk 43 and a keyboard 44 are connected to the computer 32.

The illumination area S of the macro illumination device 19 has a diameter of about 100 mm. This is a macro TV
Assuming that the magnification of the TV lens 21 of the camera 22 is 1/10,
Assuming that the size of the imaging tube of the macro TV camera 22 is 2/3 inch, the actual light receiving surface is about 8 × 6 mm.
It is a value obtained by multiplying a diagonal length of 10 mm of a 6 mm rectangle by a lens magnification. However, this setting should be set in consideration of the moiré caused by the liquid crystal pattern and the size of the camera, and the above setting is used here for easy understanding. The actual size of one area is 80 × 60 mm (corresponding to 8 × 6 mm on the light receiving surface of the TV camera 22).

In the present embodiment, as shown in FIG. 5, the substrate 10 is divided into a 6 × 5 matrix, and A1, A2,.
.., F5, F6. Therefore, the macro observation system 17
L1 between the optical axis of the micro observation system 18 and the optical axis of the objective lens 24, and the X stage 13 and the Y stage 15
Are stored in the computer 32 in advance, and the center of each area is set to the TV camera 2 for each area.
The coordinates that match the center of the optical axis 2 (match with the center of the monitor screen) are obtained and set in the computer 32 in advance.

Next, the operation of the present embodiment configured as described above will be described with reference to FIGS.

When the computer 32 receives the macro observation request from the keyboard 44, the current coordinates of the XY stage are determined from the value of the scale counter 37, and the controller is adjusted so that the coordinates of the XY stage and the center coordinates of the area A1 match. The controller 33 sends a command to the controller 33 to control the driver 34. At the same time, a switching signal is sent to the switching unit 38 so that the T
The V signal is selected and input to the display device 39. as a result,
As shown in FIG. 6, the monitor screen M of the display device 39 includes
A macro observation image (substrate image) in which the center of the area A1 reaches the monitor center O is displayed. A mouse mark Q is displayed on the same screen M.

Here, the observer operates the mouse 41 to superimpose the mouse mark Q on the defective portion on the monitor screen M, and presses the input button 41a of the mouse 41.

When the input button 41a of the mouse 41 is pressed, the distance L2 between the mouse mark position on the monitor screen M and the monitor center O is read by the image processing circuit 42. The read distance L2 is converted into a value corresponding to the magnification of the TV lens 21, and converted into coordinates on the XY stage. The input coordinates of the defective part thus obtained are stored in the storage unit together with the defective part number. Defective part numbers are numbered by serial numbers. The computer 32 receives the type of defect from the keyboard 44 simultaneously with the input of the coordinates of the defect. For example, the types of defects are assigned in advance to the numeric keys (No. 1 to No. 30) of the keyboard.
The type of defect is recognized on the computer side, such as "scratch" for the first key and "particles" for the second key.

The computer 32 superimposes and displays a mark of a different shape stored in advance in accordance with the type of defect on the defective portion on the monitor screen. In the example shown in FIG.
A defective part recognized as “scratch” is indicated by a round mark R.

Next, if there is an instruction to end the coordinate input in the area A1, the process moves to the next area A2. In the area change, since the current coordinates of the XY stage and the coordinates after the movement are known in advance, a stage control amount that allows the center of the adjacent area to coincide with the center of the monitor screen is set in advance. By driving the motor 31 by the stage control amount,
The XY stage moves as long as the center of the adjacent area matches the center of the monitor screen.

When the macro observation of all the areas is completed as described above, the micro observation is executed after waiting for the micro observation request.

When the computer 32 receives the micro observation request from the keyboard 44, the computer 32 sends a switching signal to the switch 38 to input the TV signal of the micro TV camera 27 to the display device 39, and stores the defect stored during the macro observation. The input coordinates of the part are read in ascending order of the defective part number. Then, based on the count value of the scale counter 37, the optical axis position coordinates of the micro observation system with respect to the origin of the XY stage, and the read input coordinates of the defect, the defect is moved to the optical axis position of the micro observation system. The required amount of stage control is calculated, and the motor 31 is controlled in accordance with the calculated amount of stage control.
Drive.

X driven by the stage control amount
When the defective portion comes directly below the optical axis of the micro observation system by the Y stage, the defective portion arranged on the optical axis is spot-lighted by the illumination device 23. The illuminated image of the defective portion is enlarged at a high magnification by the observation optical system of the microscope (the objective lens 24 and the like) and forms an image on the light receiving surface of the micro TV camera 27.

Here, actually, the image is not captured by the high-magnification objective lens 24 by one stage control.
In the first stage control, focusing is performed with a relatively low-magnification (5 ×, 10 ×) objective lens in consideration of the coordinate accuracy in macro observation. Next, after the defect image projected on the monitor screen is brought to the center of the monitor screen, switching to a high-magnification objective lens is performed to perform detailed observation.

Next, the computer 32 operates the keyboard 4
Waiting for an instruction to change the defective part from Step 4, if the change instruction is input, it is determined whether or not the stored defective part remains, and if so, the input coordinates of the next defective part number are read. If all the coordinates input in the macro observation are not read out and remain, the micro observation is terminated.

When the coordinates and type of the defective portion are input as described above, an application program for creating a histogram, a pie chart, or the like is started as needed, and
The processing data is fed back to the previous process and used for preparation of the subsequent process.

As described above, according to the present embodiment, the macro observation image is displayed on the monitor screen, the defective portion is designated on the screen using the mouse 41, and the position of the designated defective portion is displayed on the stage. The XY stage is controlled so as to automatically convert the coordinates to the coordinates of the defect and to move the defect part immediately below the optical axis of the micro observation system when moving to the micro observation. This greatly simplifies the coordinate input work for the defect part. In addition, it is not necessary to look for a defective portion with the naked eye during micro observation, and dust and the like do not fall on the substrate 10 from the observer, so that the contamination is improved.

Further, according to the present embodiment, since the defect type is input when the coordinates of the defective portion are input in the macro observation, data necessary for quality control such as the type and number of defects can be obtained.

By the way, if the macro observation area (coordinate input range) is displayed on the entire monitor screen, it is difficult to observe a defect at the boundary between the relevant area and the adjacent area. There is a possibility that it will not be known.

Therefore, such a problem can be solved by adopting a method of a coordinate input screen as shown in FIGS. In the above embodiment, the TV lens 21 of the macro TV camera
Although a single area is displayed on the entire monitor screen using a 10 × magnification, in this modification, for example, the TV lens 21
Use the one with a magnification of 1 / 15x for the area (80m
The area corresponding to (m × 60 mm) is framed on the monitor screen to separate the coordinate input target range from the other area.

With reference to FIG. 7 and FIG. 9, a description will be given of a process when the area C4 is displayed on the monitor as a coordinate input target area.

In this modification, the center of the area C4 is located at the optical axis position of the macro observation system, and the macro observation image is captured via a TV lens having a real field of view larger than one area.
The captured macro observation image is displayed on the monitor screen with the center of the area C4 serving as the coordinate input target area as the monitor center.

Next, on the monitor screen M, a frame indicating the area N of the area C4 which is the coordinate input target area is superimposed and displayed. The observer can recognize that the area N is a coordinate input target area.

On the other hand, it is determined whether or not an input defective portion exists in a region other than the area C4 in the macro image displayed on the monitor screen M. Since macro observation has been completed for A1 to C3, there is a possibility that an input defective portion exists in those areas. If there is an input defective portion in an area other than the area C4, the input mark R is displayed so as to overlap the corresponding defective portion.

If the coordinates of the defective part are input to the area C4, the input coordinates are stored together with the defective part number.
In addition, the input completion mark is displayed on the relevant part.

According to this modified example, the surrounding area of the coordinate input target area is displayed on the same screen, and if there is a defective area in which the coordinates of the defective portion have been input, the input completion mark is displayed. Therefore, it is easy to determine whether or not the input has been made at the boundary between the adjacent area, and it is possible to prevent an input drop or an error such as a double input.

As shown in FIG. 8, the moving amount per step when changing the area is made smaller than that in the above-described embodiment, and a part of the adjacent area is displayed. In this case, as in the above embodiment, 1/10 × T
A V lens can be used. In FIG. 8, an area A2 indicated by oblique lines is set as a coordinate input target area.
It can be recognized from the screen that the defect A at the boundary between the area A1 and the area A2 has already been input during the inspection of the area A1.

In the macro observation system of the above-described embodiment, the focused light is applied to the substrate 10, but the light may not be focused.

FIGS. 10 to 11A and 11B show modified examples of the illumination device in the macro observation system of the above embodiment.

The modified example shown in FIG.
This is an example of an interference optical system that irradiates light emitted from a lens 53 with a half mirror 52 to a lens 53 and irradiates the substrate 10 with interference light. The reflected light from the substrate 10 illuminated by the interference optical system is captured and displayed by a TV camera.

In this modification, film unevenness is mainly inspected. When the TV lens 21 is disposed at a distance from the light emitted from the fiber 51 to the collimator lens 53, that is, at a position conjugate with the focal length of the collimator lens 53, the TV lens 21 becomes a filament image from a lighting device (not shown). , The inspection for film unevenness cannot be performed. Therefore, the TV lens 21 is not disposed at the conjugate position, but rather than the conjugate position.
Are arranged at positions distant from the optical axis. FIG.
In the modified examples shown in (a) and (b), a fiber group 54 in which a large number of optical fibers are linearly bundled is irradiated at an angle nearly parallel to the substrate 10. The reflected light from the substrate 10 due to the oblique incidence on the substrate 10
The light is condensed by the lens 21 and formed on a TV camera to obtain a macro observation image.

According to this modification, the LCD pattern on the substrate 10 disappears, and only the reflected light from the dust and flaws is reflected on the TV.
Since the light enters the camera, there is an advantage that the influence of moire on the light receiving surface of the TV camera 22 can be removed.

FIG. 12 shows a modification of the coordinate input means in place of the mouse in the above embodiment. In this modification, a box 56 with a built-in trackball 55
D alphabet keys, 1 to 4 numeric keys, A-1 to A-4 keys for classifying types of defects, an input button for instructing coordinate input, and a cancel button for canceling. I have. For example, on the computer side, A-1
The type of each key is discriminated, and individual processing assigned to each key is executed, such as recognizing a large scratch, A-2 a small scratch, A-3 a large dust, and A-4 a small dust. Keep it.

Alternatively, a number of 1 to 30 corresponding to the type of defect is displayed on the monitor screen, and after inputting the defect, a matching mark is added to the number, and the computer recognizes the type of defect from the input, and You may comprise so that an observer may recognize later.

The coordinate input means is not limited to a mouse. For example, a panel having a signal line called a digitizer can be used. By applying a probe to the panel, a mark appears at a corresponding position on the monitor screen corresponding to the probe position of the panel.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

[0058]

As described above in detail, according to the present invention, the transition from macro observation to micro observation can be automated, the stage operation can be reduced when inputting the coordinates of a defective portion, and the operation can be simplified. Definitely specify defects
Can be deleted and marked
Defects and other defects can be grasped at a glance and specified once
This prevents double input mistakes for defects that have occurred, reduces the possibility of dust falling from the operator onto the substrate, and provides data necessary for process quality control such as the type and number of defects. An appearance inspection device that can be obtained can be provided.

[Brief description of the drawings]

FIG. 1 is a functional configuration diagram of a visual inspection device according to an embodiment of the present invention.

FIG. 2 is an external view of the appearance inspection apparatus shown in FIG.

FIG. 3 is a flowchart showing a part of the operation of the visual inspection apparatus shown in FIG. 1;

FIG. 4 is a flowchart showing another part of the operation of the visual inspection apparatus shown in FIG. 1;

FIG. 5 is a diagram showing a divided state when a substrate is macro-observed.

FIG. 6 is a diagram showing a monitor screen on which a macro observation image is displayed.

FIG. 7 is a diagram showing a modification of a method of displaying a macro observation image on a monitor screen.

FIG. 8 is a diagram showing another modified example of a method of displaying a macro observation image on a monitor screen.

FIG. 9 is a flowchart showing a main part of the operation content of the modification shown in FIG. 7;

FIG. 10 is a view showing a modification of the illumination device in the appearance inspection device shown in FIG.

11 is a diagram showing another modification of the illumination device in the appearance inspection device shown in FIG.

12 is a diagram showing a modification of the coordinate input means in the visual inspection device shown in FIG.

FIG. 13 is a perspective view of an appearance inspection apparatus in which a macro observation system and a micro observation system are linked.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Substrate 13 ... Y stage 15 ... X stage 17 ... Macro observation system 18 ... Micro observation system 19 ... Macro illumination device 21, 26 ... TV lens 22 ... Macro TV camera 23 ... Micro illumination device 24 ... Objective lens 27 ... Micro TV Camera 32 Computer 39 Display 41 Mouse

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01B 11/24 G01N 21/88 G09F 9/00 353 H01L 21/66 G02F 1/13 101

Claims (4)

(57) [Claims] 1. Between a macro observation area and a micro observation area
An electric stage capable of moving, the disposed macro observation area, a macro observation system the subject placed on the motorized stage to form a subject image through the low magnification of the lens, the micro observation region disposed, the micro observation system for forming an object image of the subject placed on the electric stage through the high magnification of the lens, the image signal the subject image formed by the macro observation system Macro image input means for converting the image of the subject, display means for displaying the object image converted by the macro image input means, and designation of designating a target portion of the object image on a display screen of the display means and means, the coordinate position of the specified attention site in the specifying means the electrodepositing
Converted to the coordinate position of the moving stage , stored in the storage means, and already input to the target part displayed on the display means.
Subjected Mino mark, also the electric stay as attention site on the basis of the coordinate position data of the attention area read from the storage means is moved in the optical axis position of the micro observation system
And a control means for controlling the image. 2. The control means according to claim 1, wherein
The observation area is divided into a plurality of observation areas
I will bring it to the macro observation area of the macro observation system in order
The visual inspection device according to claim 1, wherein the movement of the electric stage is controlled as described above. 3. The control means according to claim 1 , wherein
The heart coordinates are set in advance and the view displayed on the display means is set.
From the observation area and the center coordinates of the other observation area,
Calculate the moving amount of the cottage and the center of the other observation area is in front.
The motorized stay is aligned with the optical axis of the macro observation system.
3. The visual inspection apparatus according to claim 2 , wherein the movement of the laser is controlled . 4. The control means displays the information on the display means.
On the macro observation image of the observation area
A frame indicating the rear is superimposed and displayed outside the frame
Attention already specified in the adjacent observation area
3. The visual inspection device according to claim 2 , wherein the input mark is attached to a part .