JPH0784010A - Non-contact multiprobe - Google Patents

Abstract

PURPOSE:To obtain a non-contact multiprobe which achieves a high inspection accuracy at a low cost and moreover, with a simple construction by producing a number of probe electrodes similar to a pixel electrode integral corresponding to the pitch of the pixel electrode. CONSTITUTION:This apparatus is provided with an FPC(flexible printed circuit), a plurality of probe electrodes 2 which have a shape the same as or smaller than pixel electrodes arranged on a substrate to be inspected and are arranged horizontal in one row on the surface of the FPC substrate 1 with an interval of a pixel pitch P, ground earth electrodes 6 formed surrounding the probe electrodes 2 through a slight gap 2a from the probe electrodes 2, and a peep window 3 for positioning which are provided on the ground earth electrode 6 at both ends of the probe electrodes 2 arranged horizontal in one row. Moreover, a leader line 5 which is formed on the rear of the FPC substrate 1 through a through hole 4 is connected to the probe electrodes 2 separately and a glass base is provided to fix the FPC substrate 1 in such a manner that the probe electrodes are positioned on the top surface thereof while placed out side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact probe used in an inspection apparatus for inspecting a thin film transistor active matrix substrate, for example.

[0002]

2. Description of the Related Art A thin film transistor active matrix substrate includes a plurality of data lines, gate lines, and a thin film transistor "Thin Film Transistor (hereinafter, referred to as" Thin Film Transistor ").
"Abbreviated as TFT)", a pixel electrode and a capacitive element are formed on a glass substrate by film formation and photolithography technology. Due to dust, photoresist defects, and the like in this manufacturing process, defects such as wiring short circuits, disconnections, and TFT defects occur.

Conventionally, as a defect inspection of this thin film transistor active matrix substrate, a method of measuring electrical resistance of all gate lines and data lines in the substrate and detecting short circuit and disconnection has been performed.

On the other hand, the inspection for each pixel electrode including defective TFTs is performed by not inspecting all the pixel electrodes but by measuring the TFTs provided around the matrix as a measurement sample.

As a method of inspecting all the TFTs in the display area, it is possible to apply a mechanical contact probe to each pixel electrode, but this method damages the pixel electrode. Moreover, it is not practical because it requires a huge number of measurements (one liquid crystal display is composed of approximately 100,000 or more pixel electrodes). Therefore, recently, as a method for testing all pixel electrodes, a method for inspecting the pixel electrode potential using an electro-optical element (Japanese Patent Application Laid-Open No. 3-142498).
Japanese Patent Application Laid-Open No. 3-20012), a method of inspecting by detecting electric charges accumulated in a capacitive element for each pixel electrode
No. 1), there is proposed a method of inspecting a pixel electrode defect by impedance analysis using the fact that the impedance of each pixel electrode changes by turning the TFT on and off.

As a practical example of the above-described inspection method, an AC voltage is applied to the data line connected to the pixel electrode to be inspected on the thin film transistor active matrix substrate, and a voltage for turning on the TFT is applied to the gate line. As a result, a coaxial probe that is positioned directly above the pixel electrode to be inspected and is in non-contact with the pixel electrode to be inspected is used as the AC potential of the pixel electrode connected to the TFT. The AC potential of the pixel electrode to be inspected is guided to the amplifier via the electrostatic capacitance between them and detected, and defects such as short circuit, disconnection and defective TFT of the pixel electrode to be inspected are inspected according to the detected state of this AC potential. A method (Japanese Patent Application No. 4-79399) has been proposed.

[0007]

However, the coaxial non-contact probe used to carry out the above inspection method is a single probe, and a plurality of probes are used to effectively carry out the above inspection method. Therefore, it is desired to shorten the inspection time by simultaneously inspecting a plurality of pixel electrodes.

Therefore, conventionally, as shown in FIG. 10, a plurality of coaxial cables 112 are arranged in parallel to form a single non-contact multi-probe, but the electrodes are similar to the pixel electrodes of the thin film transistor active matrix substrate. There is a problem that the shape cannot be made rectangular and efficient and highly accurate potential measurement cannot be performed. That is, the coaxial cable 112
It is difficult to align the pixel electrode and the probe electrode with a non-contact multi-probe in which plural probe electrodes are arranged side by side, and the probe electrode is attached to the pixel electrode having a narrow pitch equal to or smaller than the diameter of the coaxial cable 112. There is a problem in that they cannot be arranged while maintaining a sufficient shield effect between them.

The present invention has been made to solve the above-mentioned problems, and a large number of probe electrodes are formed in correspondence with the pixel electrode pitch to be inspected, and efficient and highly accurate inspection is performed. It is an object of the present invention to provide a non-contact multi-probe that has a simple structure capable of performing the above-mentioned steps, is easy to assemble and adjust, and is inexpensive.

[0010]

A non-contact multi-probe according to the present invention has the same shape as a flexible printed circuit board having flexibility and a pixel electrode arranged in a matrix on a substrate to be inspected or a shape smaller than the pixel electrode. A plurality of probe electrodes formed in a horizontal row on the front surface of the flexible printed circuit board at the same pitch as the pixel electrodes of the substrate to be inspected, and the probe electrodes with a slight gap from the probe electrodes. A shield ground ground electrode formed so as to surround, and a viewing window provided on the ground ground electrodes at both ends of a plurality of probe electrodes formed in a horizontal row, with the probe electrode in the viewing window. A viewing window having alignment markers patterned in a corresponding shape and pitch, and a slit formed on the back surface of the flexible printed circuit board. A lead wire connected to each probe electrode through a hole, and a glass base for adhering and fixing the flexible printed circuit board so that the probe electrode is located on the top surface and is on the outside. It is a feature.

[0011]

In the non-contact multi-probe of the present invention, a plurality of probes having the same shape as the pixel electrode or a shape smaller than the pixel electrode are horizontally arranged at the same pitch as the pixel electrode on the front surface of the flexible printed circuit board having flexibility. They are arranged in a line. The probe electrode is shielded by a ground ground electrode formed so as to surround the probe electrode via a slight gap. The probe electrode is fixed to the top surface of the glass base so that the probe electrode is on the outside. The probe electrode is connected to a lead wire formed on the back surface of the flexible printed circuit board through a through hole. Therefore, the probe electrodes can be arranged according to the pitch of the pixel electrodes, and efficient and highly accurate inspection can be performed.

Further, a viewing window is provided in the ground ground electrodes at both ends of the plurality of probe electrodes arranged in a horizontal row, and alignment markers patterned in the same shape and at the same pitch as the probe electrodes are provided in the viewing windows. Since it has, the relative alignment of the probe electrode and the pixel electrode can be easily performed.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. 1 is a development view of a flexible printed circuit board showing the arrangement of probe electrodes and lead lines, FIG. 2 is an enlarged view of a part of the probe electrode formation surface, and FIG. 3 is a lead line formation surface (electrode formation surface of FIG. 2). Figure 4
[Fig. 3] is an enlarged view of a viewing window forming portion.

In FIGS. 1 to 4, reference numeral 1 denotes a flexible printed circuit board (hereinafter referred to as an FPC board) in which an ultrathin insulating sheet such as polyimide is used as a base material and copper foil is applied to both front and back surfaces by, for example, plating or vapor deposition. ) 2 has the same shape as the pixel electrodes arranged in a matrix on the substrate to be inspected or slightly smaller than the pixel electrodes, and holds the pixel electrode pitch P to form one row of the FPC boards 1 in the width direction. A plurality of probe electrodes 3 disposed on the front surface are used as alignment viewing windows for viewing the pixel electrodes provided with the pixel electrode pitch P or an integer multiple of the pitch from the end probe electrodes 2. Is. In this case, a base material having a thickness of about 25 μm and having transparency is used, and the viewing window 3 is formed by omitting the copper foil applied to both front and back surfaces of the base material. Further, the viewing window 3 may have a size corresponding to one pixel electrode, but should be so sized that a plurality of pixel electrodes, for example, three pixel electrodes can be seen for easy alignment. , A marker 3a for alignment with a pixel electrode on a transparent base material
1 to 3a3 are formed. In this example, three alignment markers 3a are shown, but the number may be increased or decreased as necessary. Further, the viewing windows 3 may be provided at both ends of the FPC board 1.

The probe electrode 2 is connected to a lead wire 5 provided on the back surface of the FPC board 1 by a through hole 4. On the other hand, the probe electrode 2 includes a ground ground electrode 6 (FPC board) via a slight gap 2a in order to remove electrical influences from pixel electrodes other than the pixel electrode to be inspected and data lines and gate lines adjacent to the pixel electrode to be inspected. 1 is surrounded by copper foil plating), and the lead wire 5 on the back surface is also connected to the ground ground electrode 7 (on the FPC board 1) through a slight gap 5a to avoid crosstalk between adjacent probe electrodes. It is surrounded by copper foil plating. Further, the lead lines 5 may be alternately drawn as shown in the figure in order to reduce the lead density. Reference numeral 8 is a connector portion for connecting the lead wire 5 to an external amplifier (not shown).

FIG. 5 shows an example of the structure of the non-contact multi-probe head of the present invention. The FPC board 1 provided with the probe electrodes 2 is shown in FIG. 6 on the surface of a prism-shaped glass base 9. The probe electrode 2 is positioned on the top surface of the glass base 9 and is fixed by an adhesive or the like so that the probe electrode 2 is on the outer side, thereby forming the non-contact multi-probe 10.

The glass base 9 is attached to the glass holding mechanism 11, and the connector portion 8 is attached to the processing substrate 1.
It is connected to the second connector portion 13 and is brought close to the inspected substrate 21 by a Z-direction slide mechanism (not shown) to perform the above-mentioned potential measurement. In this case, the probe electrode 2
The position of the pixel electrode 35 to be inspected is aligned with the microscope 1 from above.
Markers 3a1 to 3a3 formed on the viewing window 3 using 6
(See FIG. 4) and the adjacent electrode of the pixel electrode to be inspected facing the probe electrode are overlapped with each other, so that this alignment can be performed easily and accurately.

Hereinafter, the non-contact multi-probe 10 of the present invention will be described.
An example of the inspection device using the will be described with reference to FIG. First, a substrate 22 to be inspected is attached to a chuck 22 capable of adsorbing the substrate.
Fixed on.

Then, facing the substrate to be inspected 21,
The non-contact probe 10 of the present invention having the above-described configuration is supported by the mechanism section 24 which is positionable and movable in the height direction Z and the X direction in the drawing.

On the other hand, the chuck 22 has a mechanism portion 27 which can be positioned and moved in the Y direction which is perpendicular to the X direction and perpendicular to the paper surface.
Is supported by using both mechanism parts 24 and 27,
The non-contact probe 10 can be positioned on an arbitrary pixel electrode on the substrate 21 with an arbitrary distance.

The contact type probe 28 is a probe for supplying a voltage to the data line and the gate line, and is connected to a power source (not shown). In FIG. 7, 25 is an X-direction positioning guide, and 26 is a gantry.

FIG. 8 shows a typical structure of one pixel electrode of the substrate 21 to be inspected.
2, having a drain contact 33 and a gate contact 34. The source contact 32 is connected to the pixel electrode 35, the drain contact 33 is connected to the data line 36, and the gate contact 34 is connected to the gate line 37. The pixel electrode 35 is connected to an electrode of a capacitance element 38 that forms a storage capacitance, and the other electrode of the capacitance element 38 is connected to a grounded counter electrode line 39 for storage capacitance called a Cs line. .

The substrate 21 to be inspected has such a pixel electrode 3
Each pixel electrode 35 is addressable by using a specific gate line and data line. The frequency f is applied to the data line that addresses the pixel electrode to be inspected.
By applying an AC voltage of (Hz) and an appropriate bias voltage to the gate line for addressing the pixel electrode to be inspected, the TFT 31 can always be turned on or off with respect to the AC voltage. Under such a condition, the potential of the pixel electrode 35 to be inspected has an AC component of frequency f (Hz), and the amplitude of the AC component greatly differs when the TFT is turned on and when it is turned off.

In order to detect the AC potential of the pixel electrode to be inspected, as shown in FIGS. 9A and 9B, the non-contact multi-probe 10 is connected to the line including the pixel electrodes 35, 42 and 43 to be inspected. Position on top with appropriate distance. For example, by applying an AC voltage to the data line 36 for addressing the inspected pixel electrode 35 and applying a control voltage of the TFT 31 for controlling the inspected pixel electrode to the similarly addressed gate line 37, the inspected pixel electrode 35 becomes Whether or not it is operating normally is detected by measuring the potential of the probe electrode facing the inspected pixel electrode 35 of the non-contact multi-probe 10. At this time, if the adjacent pixel electrodes 42 and 43 are driven at the same time, the operation can be detected at the same time. In FIG. 9, 40 and 41 are the pixel electrodes 3 to be inspected.
5 is a pixel electrode adjacent to the pixel electrode to be inspected (a common data line is in contact with the inspected pixel electrode); Shows.

As described above, while the non-contact multi-probe 10 is moved by the driving mechanism shown in FIG. 7, a plurality of pixel electrodes driven immediately below the non-contact multi-probe 10 are inspected efficiently and quickly at one time. be able to.

[0026]

As described above, according to the present invention, the probe electrode of the non-contact multi-probe is formed on the front surface of the flexible printed circuit board having the same shape as the pixel electrode or a shape smaller than the pixel electrode. Since a plurality of electrodes are arranged in a horizontal row, it is possible to easily arrange the probe electrodes according to the pitch of the pixel electrodes, and it is possible to efficiently and quickly inspect a plurality of pixel electrodes at once. .

Further, since the probe electrodes are shielded by a ground ground electrode formed so as to surround the probe electrodes via a slight gap, the shield between the probe electrodes is surely performed. Further, a viewing window is provided in the ground ground electrodes at both ends of the plurality of probe electrodes arranged in a horizontal row, and positioning markers patterned in accordance with the shape and pitch of the probe electrodes are provided in the viewing window. Therefore, the relative alignment between the probe electrode and the pixel electrode can be easily performed, and the pixel electrode with high reliability can be inspected.

Further, the probe electrode and the viewing window can be easily and precisely formed on the flexible printed circuit board by a pattern forming technique, and a highly accurate non-contact multi-probe can be formed. The non-contact multi-probe can be easily assembled and adjusted, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a development view of a flexible printed circuit board used in a non-contact multi-probe according to the present invention.

FIG. 2 is an enlarged view of a part of a probe electrode forming surface of the flexible printed circuit board of FIG.

3 is an enlarged view of a part of a lead line forming surface of the flexible printed circuit board of FIG.

4 is an enlarged view of a viewing window forming portion of the flexible printed circuit board of FIG.

FIG. 5 is a perspective view showing an assembled state of the non-contact multi-probe according to the present invention.

FIG. 6 is a perspective view of a glass base on which a flexible printed circuit board of the non-contact multi-probe according to the present invention is assembled.

FIG. 7 is a front view of an inspection apparatus using the non-contact multi-probe according to the present invention.

FIG. 8 is a configuration diagram of one pixel electrode of a substrate to be inspected.

FIG. 9 is a perspective view showing a substrate to be inspected and a state in which a non-contact multi-probe is positioned on the substrate to be inspected.

FIG. 10 is a perspective view of a conventional non-contact multi-probe.

[Explanation of symbols]

 1 flexible printed circuit board 2 probe electrode 3 viewing window 4 through hole 5 lead wire 6 ground ground electrode 9 glass base

Claims (1)

[Claims] 1. A flexible printed circuit board having flexibility, the pixel electrode having the same shape as or smaller than the pixel electrodes arranged in a matrix on the inspected substrate, and having the same pitch as the pixel electrodes of the inspected substrate. A plurality of probe electrodes formed in a horizontal row on the front surface of the flexible printed circuit board; and a ground ground electrode for a shield formed to surround the probe electrodes with a slight gap from the probe electrodes. , A sighting window provided on the ground grounding electrodes at both ends of a plurality of probe electrodes formed in a horizontal row, the alignment marker being patterned in the sighting window in a shape and pitch corresponding to the probe electrode. A viewing window having, and formed on the back surface of the flexible printed circuit board,
A lead wire connected to each probe electrode through a through hole; and a glass base for adhesively fixing the flexible printed circuit board so that the probe electrode is located on the top surface and is on the outside. Non-contact multi-probe.