JPH03163338A - Attached-dust inspecting apparatus - Google Patents

Abstract

PURPOSE:To make it possible to perform inspections characterized by a movable method, a low cost and high sensivity by projecting spot light on the surface of one part in a large square-shaped substrate which is held with a rotary body, and detecting attached dust based on the state of the reflected light. CONSTITUTION:A substrate to be inspected 1 is mounted on a rotary table 2, and a start signal S1 is inputted. Then, a detector 16 is moved to the position of a sensor 26 from the position of a sensor 17 with a motor 25. When the center of the detector approximately agrees with a rotary shafts 3 of the sensor 26, the inspection is started. The motor 25 is rotated in the reverse direction. The detector 16 is relatively moved along the surface of the substrate 1 toward the sensor 27. Spot light is projected during the movement, and the state of the reflected light is detected. That is, when the dust is attached to the substrate 1, the scattering light is extracted and stored. The fact is confirmed after the inspection is finished. When the detector 16 is further moved by a specified distance l, the detection is finished, and the rotation of the table 2 is stopped. This detecting method is the same as the detection of a semiconductor wafer. The entire surface of the large squared substrate cannot be detected, but this method is sufficient for controlling the dust in the manufacturing line and has the advantages such as the movable method, the low cost and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an attached dust inspection device used when manufacturing large square substrates for liquid crystal display panels.

(Conventional technology) In recent years, with the spread of word processors, personal computers, LCD televisions, etc., the demand for liquid crystal displays has increased. At the same time, the demand for finer displays and larger sizes for liquid crystal displays has also increased, and quality maintenance has become extremely difficult. It is becoming more and more demanding.

In response to such demands, the adhesion of dust in the manufacturing means of liquid crystal displays poses a major problem.

Liquid crystal displays are broadly divided into a display panel, which is a liquid crystal screen, and a module that drives the display panel.In manufacturing the display panel, photo-etching and photo-etching are applied to the glass plate that serves as the substrate.
There is a buttering process in which various fine patterns are formed through a process, and a cell process in which two buttered substrates are bonded together and liquid crystal is injected between them. In either case, if dust adheres to the substrate surface during the process, fine patterns may be cut or short-circuited, and defects such as short-circuiting of the electrodes of two substrates may occur in the cell process, resulting in production problems. This will lead to deterioration of yield and quality. In particular, recent TFT (Thin Film)
In the manufacturing of display panels with transistor structure,
The garbage problem is a major issue. Therefore, it is extremely important to inspect how much dust adheres to the substrate surface during each process in order to improve yield and quality.

For this reason, recently, large glass substrate adhering dust inspection equipment scans the substrate surface with a laser spot via a polygon mirror, and at the same time moves the substrate in a direction perpendicular to the scanning direction. Devices that detect the scattered and reflected light from dust on the surface in synchronization with the movement of the dust and inspect the state of dust adhesion are beginning to be used. However, this device is large in size, is stationary, and is expensive.Furthermore, the dust detection sensitivity is poor, and the minimum dust detection level is about 1#ffi.

Therefore, conventionally, wafer dust inspection apparatuses used in the manufacture of semiconductors have been widely used. in this case,
The substrate to be inspected is limited to a round semiconductor wafer or a glass substrate of the same shape. On the other hand, in manufacturing equipment used in the manufacturing process of display panels for liquid crystal displays, large square glass plates are transported and processed.

Therefore, conventionally, the semiconductor wafer was mounted on a tray specially manufactured for dust inspection and the process was carried out, or the semiconductor wafer was fixed with adhesive tape on the above-mentioned large glass plate and the process was carried out. We are trying to understand the waste situation within the process.

However, in this method, in a continuous substrate conveyance device that uses liquid for cleaning, etching, etc., when a wafer adhesively fixed onto a glass plate is conveyed, cleaning liquid or etching liquid accumulates in the gap between the glass plate and the wafer. This will contaminate the tank, etsu, and dressing tank. Further, because there is a step between the glass surface and the wafer, the area around the step becomes dirty and dust is generated there. Therefore, it is not possible to see the state of dust adhesion when only the original glass plate is used.

(Problems to be Solved by the Invention) As described above, in the past, there has not been used an inexpensive attached dust inspection device that can directly detect dust from a large glass substrate and can be easily moved.

The present invention was developed in view of this situation, and is designed to detect dust on one side of a large rectangular substrate.
The object of the present invention is to provide a movable, inexpensive, and highly sensitive adhering dust inspection device.

[Structure of the invention]

(Means for Solving the Problems) The present invention includes a rotating body that holds and rotates a substrate to be inspected, and a spot light is projected onto the surface of the substrate to be inspected held by the rotating body, and the state of the reflected light is and a detector that moves relatively in a direction along the surface of the substrate to be inspected held by the rotating body, and detects dust in a circular area approximately in the center of the substrate to be inspected. .

(Function) In the present invention, the substrate to be inspected is rotated by driving the rotating body, and at the same time, the detector is moved relative to the substrate to be inspected from a predetermined position in the direction along the surface of the substrate. Spot light is projected onto the test board and the state of the reflected light from the board is detected. That is, dust on the surface of the substrate is detected by detecting scattered reflected light. Then, by the relative movement of the rotating body between the substrate to be inspected and the detector, dust within a circle approximately in the center of the substrate to be inspected is detected.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a substrate to be inspected consisting of a large square glass plate. Reference numeral 2 denotes a rotary table as a rotating body provided horizontally, on which the substrate 1 is placed and rotated while being sucked and held by a suction mechanism (not shown). A rotary shaft 3 provided at the lower center of the rotary table 2 is held perpendicularly to the machine frame 5 by a bearing 4.

A drive mechanism 6 is connected to the rotating shaft 3.

This drive mechanism 6 includes a pulley 7 attached to the lower part of the rotating shaft 3.
A belt 11 is stretched between a pulley 10 and a pulley 10 attached to a drive shaft 9 of a motor 8, and the drive of the motor 8 causes a pulley lO of a drive shaft 9, a belt IL pulley 7, and a rotation shaft 3.
The rotary table 2 is rotated via the rotary table 2.

Furthermore, a rotational encoder 12 and a rotational position detector 13 are provided below the rotational shaft 3. This rotational position detector 13 has a slit plate 14 in which a slit is carved at one location on the circumference fixed to the rotation Illll3, and a sensor 15 for detecting the slit position with respect to the slit plate 14 is provided. has been done.

A detector 16 is disposed above the rotary table 2 so as to be movable laterally. As shown in FIG. 2, this detector 16 is provided with a reflecting mirror 18 with an open bottom in a main body 17, and a laser projector 18 on one side of the reflecting mirror 18.
9 and the other side are provided at symmetrical positions, and a light detection sensor 21 is attached to the upper center of the reflecting mirror 18.

Then, a laser spot light }93 is projected from the laser projector 19 of the detector 16 onto the substrate 1 to be inspected held on the rotary table 2, and the specularly reflected light 19b is reflected by the reflection mirror 18.
passes through the through hole 20 to the outside, and the light detection sensor 21
On the other hand, if foreign matter (dust) adheres to the substrate 1, this foreign matter generates scattered reflected light 19c, and this scattered reflected light 19c is reflected by the reflection mirror 18 and becomes light. The light enters the detection sensor 21 and is photoelectrically converted to detect attached dust.

Further, as shown in FIG. 1, a moving mechanism 22 for the detector l6 is provided. This moving mechanism 22 has a screw shaft 24 horizontally supported by a bearing 23 on the machine frame 5.
A pulse motor 25 is connected to one end of this screw shaft 24, and the main body 17 of the detector 16 is screwed and supported on the screw shaft 24 so as to be able to move forward and backward, and Sensors 26 and 27 are arranged at the position and the side position, and the screw shaft 24 is rotated forward and backward by the drive of the motor 25, so that the detector 16 is in the full direction.
, It is designed to move forward and backward in 27 steps.

28 is a control device, and this control device 28 is connected to a motor drive circuit 29. The motors 8 and 25 are connected via 30,
Further, the control device 28 is connected to the rotary encoder 12, the sensor 15 of the rotary position detector 13, and an AND circuit 31 connected to the sensor 15 and the sensor 26, and further connected to the preamplifier 32 and the It is connected to receive signals via an A/D converter 33 connected to the rotary encoder 12.

Further, the rotary table 2, the detector l6, the moving mechanism 22 of the detector 16, the sensor 26 . The entire dust detection mechanism consisting of 27 etc. is covered with a dark box (not shown).
It is designed not to be affected by ambient light during detection. Furthermore, the dark box has a clean unit that flows clean air from the top through an air filter to keep the inside of the dark box dust-free.

Next, the operation will be explained.

First, the substrate 1 to be inspected is set on the rotary table 2. At the start of setting the substrate 1, the detector 1G is at the position of the sensor 27, and the rotary table 2 is stopped at a predetermined position. In this case, the slit of the slit plate l4 of the rotational position detector l3 is being detected by the sensor 15. That is, the positional relationship between the large square substrate 1 and the rotary table 2 is defined, and the rotational position of the rotary table 2 is determined so that the substrate 1 can be easily set.

Then, the substrate I is placed on the rotary table 2 and fixed by a vacuum mechanism of the rotary table 2 (not shown). When the start signal St is input to the control device 28 in this state,
The motor 25 of the moving mechanism 22 is driven by the motor drive circuit 30.
is driven, and the detector 1G begins to move from the position of the sensor 27 toward the position of the sensor 26 due to the rotation of the screw transport 24. At the same time, the motor 8 of the drive mechanism 6 is driven by the motor drive circuit 29, and the pulley 7, IO, belt 11
The rotary table 2 is rotated to a predetermined rotation speed via the rotation shaft 3, and the speed is maintained.

Then, when the detector I6 comes to the position of the sensor 26, the third
As shown in the figure, a rotational position detector 1 that indicates the rotational position of the substrate 1
An AND signal S3 is generated by an AND circuit 3l of the output signal S1 of the sensor 15 of No. 3 and the output signal S2 of the sensor 2G. At this time, the center position of the detector 16 is
and almost coincides with the center position of rotation #i3 of the rotary table 2.

This state becomes the dust detection start position, that is, the above A
The ND signal S3 becomes a dust detection start signal, and at the same time becomes a reverse feed signal for the detector 16. As a result, the motor 25 rotates in the opposite direction, and the detector l6 starts moving relatively from the sensor 26 position toward the sensor 27 position in a direction along the surface of the substrate 1 held on the rotary table 2. do.

At the same time, a spot light is projected onto the substrate 1 from the detector l6, and the state of the reflected light is detected.

That is, the specularly reflected light 19b of the spot light 19i projected from the laser projector 19 of the detector l6 is reflected by the reflection mirror 1.
However, if foreign matter (dust) adheres to the substrate 1, scattered reflected light 19C will be generated, and the scattered reflected light 19c will not enter the light detection sensor 2l through the through hole 20 of 8. 18 efficiently enters the light detection sensor 21,
Photoelectrically converted.

Then, the detection output of the detector 16 is amplified by the preamplifier 32, and then A/D converted and sampled by the A/D converter 33 at the timing of the signal S4 from the rotary encoder 12, and sequentially recorded in the memory of the control device 28. be done.

Then, when the detector 16 moves by a predetermined distance l, the dust detection ends, the motor 8 decelerates, and the rotary table 2 stops when the sensor l5 detects the slit. That is, the substrate 1 to be inspected is stopped at a predetermined position from which it can be easily taken out.

On the other hand, the detector l6 reaches the position of the sensor 27, that is,
It moves to a position away from the substrate 1 placed on the rotary table 2 and stops. Next, according to the operator's instructions, the control device 26 reads the data of the detector 16 recorded in the memory.
Based on the positional information on the substrate 1 calculated from the number of pulses of the rotary encoder 12 and the rotational speed of the rotary table 2, the size of the dust and its positional distribution are processed based on an appropriate algorithm, and the data is processed on a display or printing device (not shown). Display the output in .

Therefore, as shown in FIG. 4, dust is detected within a circle with a diameter of 2 l at approximately the center of the substrate 1, and the dust location is accurately displayed with respect to the substrate 1. In addition, the same detection speed and accuracy as in semiconductor wafer dust detection can be obtained.

The dust detection principle is exactly the same as the dust detection method for wafers, but in cases where dust cannot be detected over the entire surface of the large rectangular substrate 1, by incorporating the idea of inspecting a considerable circular area approximately in the center, It is small, lightweight, inexpensive, and enables high-performance garbage inspection. Therefore, since it is easily movable, equipment management and atmospheric dust management can be easily carried out by bringing it to various parts of the production line and easily inspecting it for dust. Note that in this inspection, only the circular area at the center of the square substrate is inspected for dust, but this is practically sufficient for controlling the dust level on the production line. Furthermore, by expanding the software processing, the dust detection area can be made into a donut shape. In other words, since it is possible to detect dust in an area with a diameter of 2g to (2l+2L), the area within the diameter of 2l is first detected as dust, and then the area with a diameter of 21 - (2l + 2L) is detected to remove dust from the internal memory. It is possible to detect debris over a large area without increasing the area.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a movable, inexpensive, and highly sensitive attached dust inspection device that detects dust on one side of a large square substrate.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the device of the present invention, Fig. 2 is a sectional view of the detector shown in Fig. 1, Fig. 3 is a signal waveform diagram, and Fig. 4 is a diagram showing an embodiment of the device of the present invention.
The figure is an explanatory diagram of the detection surface of the substrate to be inspected. 1. Board to be inspected, 2. Rotating body, 16. Detector.

Claims (1)

[Claims] (1) A rotating body that holds and rotates the substrate to be inspected; a spot light is emitted onto the surface of the substrate to be inspected held by this rotating body, and the state of the reflected light is detected; and the substrate is held by the rotating body. What is claimed is: 1. An attached dust inspection apparatus comprising: a detector that moves relatively in a direction along a surface of a board to be inspected, and detects dust in a circular area approximately in the center of the board to be inspected.