JP2002296201A - Defect inspection device for face plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a defect inspection device for a face plate capable of efficiently observing a detected foreign matter without decreasing efficiency in defect inspection. SOLUTION: This defect inspection device for the face plate is equipped with a memory for storing data on the detected position of a foreign matter on the face plate detected with a defect inspection part by receiving reflected light or scattered light from projected light to the face plate at the specified irradiation angle; a measuring instrument for measuring the deflection amount of the face plate; and a microscope measuring system. Data on the detected position is read out of the memory, the measuring instrument is positioned in the detected position, the deflection amount in this position is measured, the detected position of the foreign matter is corrected based on the obtained deflection amount and the specified irradiation angle, and the microscope measuring system is positioned in the corrected position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection apparatus for a face plate, and more particularly, to a surface of a substrate such as a glass substrate for a liquid crystal panel or a synthetic resin substrate, which does not decrease the efficiency of defect inspection. The present invention relates to an improvement in a foreign matter observation processing system capable of efficiently observing foreign matter. In addition,
In this specification, a foreign substance is described as being included in a defect as one of the defects.

[0002]

2. Description of the Related Art A large number of TFT elements are formed on the surface of a TFT substrate constituting a liquid crystal panel using a glass substrate as a material. If a defect such as a scratch or a foreign substance is present on the surface, the TFT element is not formed well in that part,
Since the quality of the T substrate is impaired, a necessary measure is taken by detecting the presence or absence of a defect and its location (coordinates) by a defect inspection device. In a defect inspection system, a detection optical system projects a laser beam onto a glass substrate at low-angle irradiation, receives scattered light from the defect with a photodetector, detects the defect, and converts the detection signal into a data processing unit. , The size of the defect is calculated, the type of the defect is determined, and defect data obtained by adding the coordinate value at which the defect exists is output, or the defect is displayed on the screen of the display.

There are various types of defects in a glass substrate, and representative ones are foreign substances and scratches present on the front or back surface, and bubbles present inside the substrate. Of these, foreign matter on the front surface and scratches are inconvenient defects because they impair the quality of the TFT element to be formed, but foreign matter on the back surface, scratches and bubbles inside are harmful unless they are too large. Can be ignored because there is no As described above, the three types of defects have different effects on the TFT depending on the type. In particular, it is necessary to specify the content of the foreign matter. Therefore, the contents of the defect are confirmed by positioning an observation device having a visual observation system at the coordinates where the defect is detected. This is because in order to improve the yield of the liquid crystal panel and its substrate, it is necessary to feed back the detected defect content to the manufacturing process. In addition, foreign substances adhering to the substrate surface have been conventionally observed by visual observation, and when there are many foreign substances, re-cleaning or the like is performed.

[0004]

In recent years, the display dots of a liquid crystal panel have become smaller and higher in density, and on the other hand, the size of the substrate itself has increased.
Therefore, it is required to detect minute foreign substances and defects, and the detection position accuracy is also increasing. When the size of the substrate is increased, the deflection of the substrate causes the defect detection coordinates of the defect inspection apparatus to deviate from the positions of the actually existing defects. In particular, when a defect is detected by projecting a laser beam of low-angle irradiation, the influence becomes large. Therefore, even if the observation optical system is moved to the defect detection coordinates after the defect inspection to observe the target defect, the defect is often not found. In addition, at present, when the size of the substrate is increased, it is inefficient to examine all the defect contents and feed it back to the manufacturing process.

When a foreign object is detected by a low-angle irradiation laser beam, the detection coordinates of the foreign object in a defect inspection apparatus,
The relationship with the observation position is as shown in FIG. 5 when the glass substrate is bent. Assuming that the deflection amount of the glass substrate 1 is δ, when the observation optical system 10 is moved to observe the defect (foreign matter) F, the coordinate value between the foreign matter detection coordinate P and the actual observation position coordinate is ΔL. Misalignment occurs. Therefore, it takes time to observe a target foreign substance, and an observation target may be erroneously recognized. In addition, 8
1 is a light projection optical system of the defect inspection apparatus. In the drawing, an example is shown in which the glass substrate 1 is supported around the periphery in order to emphasize the deflection. However, in a defect inspection apparatus for a liquid crystal panel, pins such as pins are provided on the rear surface of the glass substrate 1 at predetermined intervals. Often there is a support point. Glass substrate 1 such as liquid crystal panel
Does not like the adhesion of foreign substances and flaws, and the adhesion of foreign substances on the back side becomes a problem, so that the entire back surface of the table is not placed solidly. Even in the case of multi-point support, the above-described deflection always occurs. Therefore, it is conceivable that the deflection amount is measured for each measurement point by a defect inspection apparatus, and the detected coordinates are corrected by arithmetic processing to obtain the absolute coordinates. However, this requires processing time and reduces the defect inspection efficiency. There's a problem. SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem of the prior art, and to provide a face plate defect inspection apparatus capable of efficiently observing a detected foreign substance without lowering the defect inspection efficiency. To provide.

[0006]

A feature of the face plate defect inspection apparatus according to the present invention is that a face plate defect inspection apparatus having a foreign substance observing system is characterized in that reflected light from light projected on the face plate at a predetermined irradiation angle or reflected light. A memory for storing data of a detection position of a foreign substance on the face plate detected by the defect inspection unit in response to the scattered light, a measuring device for measuring a deflection amount of the face plate, and a microscope observation system, and The data is read, the measuring instrument is positioned at the detection position, the amount of deflection at that position is measured, and the detection position of the foreign object is corrected based on the obtained amount of deflection and a predetermined irradiation angle, and the position is corrected. This is for positioning the microscope observation system.

[0007]

As described above, according to the present invention, the amount of deflection is measured at the position where the foreign object is detected, and the amount of the foreign object is detected based on the amount of deflection and the irradiation angle of the light projecting system of the defect inspection unit. Since the position is corrected, the correction process is simple, the measurement error is small, and the microscope observation system can be immediately positioned at the position where the foreign object to be observed exists. As a result, the detected foreign matter can be efficiently observed without lowering the efficiency of the defect inspection, and erroneous recognition of the observed foreign matter can be prevented.

[0008]

FIG. 1 is a block diagram of a foreign matter observing system of a defect inspection apparatus according to one embodiment to which a face inspection apparatus of the present invention is applied.
FIG. 2 is an explanatory diagram of the coordinate position correction process, FIG. 3 is an explanatory diagram of the correction amount calculation in the Y direction, and FIG. 4 is an explanatory diagram of the correction amount calculation in the X direction. In FIG. 1, a defect inspection apparatus 1
Reference numeral 0 denotes a microscope observation unit 7 and a defect inspection unit 8. The microscope observation unit 7 includes an observation optical system 2, an XY stage 3 on which the glass substrate 1 is mounted, a control unit 4, a data processing unit 5, and a foreign object coordinate memory 6. Here, the foreign substance data is transferred from the defect inspection section 8 and stored in the foreign substance coordinate memory 6 of the microscope observation section 7. Note that the control unit 4, the data processing unit 5, and the foreign object coordinate memory 6 use the microscope observation unit 7
Is formed. The light projecting system and the light receiving system of the defect inspection unit 8 are located on the base table 31 adjacent to and in front of the X moving mechanism 33, as shown in FIG.
Are not shown.

The observation optical system 2 includes a microscope observation lens barrel 21 and a laser displacement meter 22 and is fixed to a moving plate 23. Observation position of microscope observation tube 21 and laser displacement meter 22
Is mounted with a displacement of Xp in the X direction. There is no shift amount in the Y direction. Note that Y
If there is a deviation in the direction, the position may be corrected by that amount (described later). The XY stage 3 has a base table 31
It comprises a Y-direction moving table 32 mounted thereon and an X moving mechanism 33 having a bridge frame supported at both ends of the base table 31 and bridged over the base table 31. The moving plate 23 is fixed to a ball nut provided on a bridge of the X moving mechanism 33, and moves the glass substrate 1 in response to driving of a driving motor 33a that drives in the X direction.
For example, moving along the longitudinal side, depending on its position,
The positioning of the moving table 32b (glass substrate 1) in the X direction is relatively performed. The Y-direction moving table 32 is
Moving table 32b in the Y direction on which glass substrate 1 is placed
And a drive motor 32a.
Is moved from the position of the moving table 32b indicated by a dotted line adjacent to the X moving mechanism 33, that is, from the inspection position of the defect inspection unit 8 to the observation position. (Solid line). Thereby, the glass substrate 1 moves along, for example, a side in the short direction of the glass substrate 1 to position the moving table 32b (glass substrate 1) in the Y direction.

The control unit 4 of the data processing device of the microscope observation unit 7 includes an X-direction driver 41, a Y-direction driver 42, an amplifier 43, a motor control board 44,
A D conversion board 45, and a bus 5 of the data processing unit 5
3 is connected. The X direction driver 41 and the Y direction driver 42 are respectively
The Y-direction drive motor 32a and the X-direction drive motor 33a are rotationally driven in accordance with the control to move the glass substrate 1 and the moving plate 23 by a predetermined amount, and move the microscope observation lens barrel 21 to the position of the foreign object to be observed. Or laser displacement meter 2
At the position of the predetermined coordinates positioned by 2, the amount of displacement there is measured. The measurement value of the laser displacement meter 22 is sent to the A / D conversion board 45 via the amplifier 43, where it is A / D converted, and the MPU
It is passed to 51.

The data processing unit 5 includes an MPU 51 and a memory 5
2 and these are interconnected via a bus 53,
These are further connected to the control unit 4 and the foreign object coordinate memory 6 via the bus 53. The memory 52 includes an observation foreign substance coordinate acquisition program 52a, a deflection amount measurement program 52b, and a coordinate correction value calculation program 52.
c, and an observation position positioning program 52d, and has a work area 52e, a parameter area 52f, and the like.

Hereinafter, the correction processing of the foreign object detection position by the processing of each program will be described with reference to FIG.
The observation foreign matter coordinate acquisition program 52a is executed by the MPU 51, and the MPU 51 stores the detected position data of the foreign matter transferred from the defect inspection unit 8 in the foreign matter coordinate memory 6.
(Step 101). Then, the first target coordinates (Xo, Yo) of the foreign substance are read from the foreign substance coordinate memory 6 (step 102) and stored in the work area 52e.
After that, the deflection amount measurement program 52b is called and M
Causes the PU 51 to execute. Deflection amount measurement program 52b
Is executed by the MPU 51, the MPU 51 reads out the coordinates (Xo, Yo) of the foreign matter from the work area 52e, moves the XY axes in accordance with the coordinates, and positions the laser displacement gauge 22 at the position of the coordinates (Xo, Yo). (Step 10
3). The deflection amount δ of the glass substrate 1 from the reference position Ps (see FIGS. 3B and 5) at that position is measured by the laser displacement meter 22 using the amplifier 43 and the A / D conversion board 4.
5 is converted into a deflection amount δ and calculated as a measured value (step 104). Note that, as described with reference to FIG. 5, the deflection amount δ is based on the position of the surface when the glass substrate 1 is horizontally supported as the reference position. this is,
The position is determined by adding the position of the support surface of the moving table 32b that supports the glass substrate 1 and the average thickness of the glass substrate 1. This reference position Ps is stored in the parameter area 52f as data input in advance. The measured deflection amount δ is stored in the work area 52e, and then the coordinate correction value calculation program 52c is called to
Cause U51 to execute.

The coordinate correction value calculation program 52c includes an MP
The MPU 51 executes the work area 52
e, the deflection amount δ is read out, and the correction amounts (ΔX, ΔY) in the X and Y directions are calculated according to the readout amount (step 105).
The program is stored in the work area 52e, and then the observation position positioning program 52d is called and the MPU 51 executes the program. The observation position positioning program 52d
The MPU 51 reads out the correction amount (ΔX, ΔY) and the coordinates (Xo, Yo) from the work area 52e, calculates (Xo + ΔX, Yo + ΔY) according to them (Step 106), and places the microscope at this position. It is positioned in the observation lens barrel 21 (step 107). In this case, the displacement Xp in the X direction between the measurement position and the observation position of the laser displacement meter 22 is automatically added to the calculation to perform the position correction. If there is a shift amount in the Y direction between the observation position and the measurement position, the correction calculation in the Y direction is also performed at this time. next,
It is determined whether the processing is completed (step 108). If the foreign object coordinate data still exists and the processing is not completed, N
The condition O is satisfied, the process returns to step 102, and the coordinates (Xo, Yo) of the next target foreign substance are read out.
The same process is continued from 03 onward. When the processing is completed, the result is YES, and the processing here is completed.

FIG. 3 shows a correction amount (Δ
(X, ΔY) is a diagram illustrating the relationship between the correction amount ΔY in the Y direction and the irradiation optical system, and FIG. 4 is a diagram illustrating the correction amount ΔX in the X direction. FIG.
FIG. 1A is an explanatory diagram when the Y-direction moving table 32b is positioned at the inspection position of the defect inspection unit 8 indicated by a dotted line adjacent to the X movement mechanism 33 in FIG. It is. The glass substrate 1 is placed on a moving table 32b in the Y direction, receives a laser beam from the light projecting optical system 81 of the defect inspection unit 8 at a low irradiation angle, and
Scan in the direction. The irradiation angle at this time is θ1 (elevation angle), and as shown in FIG.
Assuming the deflection amount δ at a certain coordinate position, the correction amount ΔY is
ΔY = δ / tan θ1. Further, the irradiation angle in the X direction is θ
If the angle is 2 (elevation angle), as shown in FIG.
Becomes ΔX = ΔY × sin θ2. Thus, the correction amount (ΔX, Δ
Y) can be calculated. The irradiation angles θ1 and θ2 are stored in the parameter area 52f, and based on this, M
The PU 51 executes the coordinate correction value calculation program 52c to calculate the correction amount.

As described above, in the embodiment, the deflection amount is measured by the laser displacement meter. However, the measuring device may be an electrostatic displacement meter or another distance measuring device. Is not limited to a laser displacement meter.
Further, in the embodiments, the example of the glass substrate of the liquid crystal panel is given, but the present invention is not limited to the glass substrate of the liquid crystal panel, and other liquid crystal substrates, liquid crystal panels, glass substrates, PDP substrates, Organic EL substrates, synthetic resin substrates, etc.
Of course, it can be applied to other face plates.

[0016]

As described above, according to the present invention, the amount of deflection is measured at the position where the foreign object is detected, and the amount of the foreign object is detected based on the amount of deflection and the irradiation angle of the light projecting system of the defect inspection unit. Since the position is corrected, the correction process is simple, the measurement error is small, and the microscope observation system can be immediately positioned at the position where the foreign object to be observed exists. As a result, the detected foreign matter can be efficiently observed without lowering the efficiency of the defect inspection, and erroneous recognition of the observed foreign matter can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a foreign matter observation system of a defect inspection apparatus according to one embodiment to which a face plate defect inspection apparatus of the present invention is applied.

FIG. 2 is an explanatory diagram of the coordinate position correction processing.

FIG. 3 is an explanatory diagram of calculation of a correction amount in a Y direction;
(A) is an explanatory diagram of the irradiation state of the light projecting optical system of the defect inspection unit, and (b) is an explanatory diagram of calculation of a correction amount in the Y direction.

FIG. 4 is an explanatory diagram of calculation of a correction amount in an X direction.

FIG. 5 is an explanatory diagram of deflection of a glass substrate of a conventional liquid crystal panel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... Observation optical system, 81 ... Projection system, 3 ...
XY stage, 4 ... control unit, 5 ... data processing unit, 51 ...
MPU, 52: memory, 53: bus, 6: foreign object coordinate memory, 7: microscope observation unit, 8: defect inspection unit, 10: defect inspection device.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/13 101 G02F 1/13 101 F term (Reference) 2F065 AA49 AA65 CC01 FF12 FF32 GG04 HH12 HH14 MM03 PP12 QQ03 QQ23 TT02 UU01 UU02 2G051 AA42 AA73 AA84 AA90 AB02 BA10 CA11 CB01 CB05 DA07 EA12 EA14 EB01 EC03 2G086 EE10 2H052 AD19 AF02 2H088 FA11 HA01 HA06 HA08 MA20

Claims (2)

[Claims] In a defect inspection apparatus for a face plate having a foreign matter observing system, reflected light or scattered light from light projected on the face plate at a predetermined irradiation angle is detected by a defect inspection unit. A memory for storing data of the detection position of the foreign matter, a measuring device for measuring the amount of deflection of the face plate, and a microscope observation system, and reading the data of the detection position from the memory and moving the measuring device to the detection position. Positioning and measuring the amount of deflection at that position, correcting the detection position of the foreign matter based on the obtained amount of deflection and the predetermined irradiation angle, and positioning the microscope observation system at the corrected position. Features a face plate defect inspection device. 2. The defect inspection section detects various defects including the foreign matter, the face plate is a substrate of a liquid crystal panel, the measuring device is a laser displacement meter, and the microscope observation is performed. The face plate defect inspection apparatus according to claim 1, further comprising a member for fixing a system and the laser displacement meter, wherein the member is moved in one of the X direction and the Y direction.