JPH05341301A - Probe needle - Google Patents

Abstract

PURPOSE:To provide the probe needle which can be brought into linear contact with an electrode pad. CONSTITUTION:A horizontal contact part 20C which is paralleled with the electrode pad 14 is formed at the front end of the probe needle 20 which is provided on a probing substrate and is brought into contact with the electrode pad 14 of a liquid crystal display substrate and this part is brought into contact with the electrode pad 14, by which the linear contact is enabled. As a result, the contact resistance is decreased and the result of inspection is stabilized.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a probe needle.

[0002]

2. Description of the Related Art Generally, an LCD (Liquid Crystal Display) using a TFT (Thin Film Transistor) has been attracting attention because it provides a very high image quality. In this type of LCD, for example, a TFT is formed on a plate-shaped glass substrate by a photolithography technique.
The pixel electrode electrically connected to the drain electrode of
A large number of pixel units arranged in such a manner as to be arranged with an FT through a gap are arranged. For example, hundreds of thousands of rectangular pixel units each having a side of several 100 μm are arranged. Then, on such an LCD substrate, transparent electrodes common to each pixel unit are arranged to face each other through a gap, and liquid crystal is sealed in the gap to form an LCD.

By the way, as the pattern on the LCD substrate becomes finer and the capacity becomes larger, due to fine particles in the manufacturing process, for example, an open short circuit between the gate and drain of a TFT, a wiring pattern and a pixel. Although a defect such as a short circuit with the electrode is likely to occur, repair cannot be performed even if a defect is found by inspection after encapsulating the liquid crystal. Therefore, each pixel unit of the LCD is inspected for operation confirmation before encapsulating the liquid crystal. ..

In this inspection, for example, an inspection electrode is provided on the back side of the glass substrate so as to face the pixel electrode, a voltage is applied to the gate electrode, and a current is supplied to the inspection electrode from a common terminal to change the drain current. The quality of each TFT is determined by detecting the flowing current. Figure 1
As shown in FIGS. 1 and 12, the probing substrate 2 for performing this inspection has a large number of probe needles 6 tilted downward from the glass epoxy resin 4 or the like, for example. The board is contacted and the signal line 8 is connected to the printed board through pogo pins or the like. The probe needles 6 are provided at equal intervals so as to correspond to the electrode pads 14 provided along the circumferential direction on the outside of the display surface 12 of the LCD substrate 10 made of glass.

The electrode pad 14 constitutes a pad group G consisting of a plurality of electrode pads 8, in the illustrated example, five electrode pads 8. The probe needle 6 of the probing substrate 2 corresponds to the one pad group G. In addition, the illustrated example has five probe needles 6. Then, the probe needle 6 and the electrode pad 14 are sequentially brought into contact with each other while the probing substrate 2 is moved along a guide mechanism 14 provided on a side portion of the LCD substrate 10 and made of, for example, a screw screw, to inspect the LCD. It is like this. Incidentally, such a probing substrate is, for example, X, Y of the LCD substrate 10.
Will be provided in each direction.

[0006]

By the way, the probe needle 6 of the probing substrate 2 as described above is made of a material having high rigidity such as tungsten, and the tip thereof is made small in order to reduce the contact resistance at the time of inspection. Electrode pad 1
Press on 4 to form a scratch and expose a new surface,
The LCD is inspected by sending an inspection signal in a state of making point contact with the pad 14. However, in this kind of almost vertical probe needle 6, although scratches are formed on the pad 14 to bring the new surface into contact with the probe needle, it is inevitable because of point contact. However, the contact resistance has a relatively large value, which results in unstable test results and inaccurate test results.

Further, as described above, fine dust or particles are generated along with the formation of scratches on the pad 14, but there is a problem that this dust causes a reduction in yield. In particular, in today's situation where the tendency toward miniaturization is increasing and LCDs of a large size of, for example, 450 mm × 450 mm have appeared, it is strongly desired to improve the above-mentioned problems of contact resistance and dust. The present invention has been made to pay attention to the above problems and to solve them effectively. An object of the present invention is to provide a probe needle that can be in line contact with an electrode pad.

[0008]

In order to solve the above problems, the present invention provides a probe needle which is provided on a probing substrate and is in contact with an electrode pad of the liquid crystal display substrate for inspecting the liquid crystal display substrate. In order to bring the probe needle into line contact with the pad, the probe needle has a horizontal contact portion parallel to the pad.

[0009]

Since the present invention is constructed as described above, the horizontal contact portion provided on the probe needle comes into linear contact with the electrode pad of the liquid crystal display substrate in a substantially parallel state. Therefore, it is possible to significantly reduce the contact resistance without causing point contact as in the conventional case and generating particles.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the probe needle according to the present invention will be described in detail below with reference to the accompanying drawings. 1 is a perspective view showing a probing substrate using a probe needle according to the present invention, FIG.
FIG. 2 is a plan view of the probing substrate shown in FIG. 1. The same parts as those of the conventional device are designated by the same reference numerals. As shown in the figure, the probing substrate 22 provided with the probe needle 20 according to the present invention has a slightly larger area so that the entire LCD substrate 10 located therebelow can be covered at one time. The LCD substrate 10 is placed on the base 24 and has a size of, for example, 450 mm × 450 mm.
Is set to. The LCD substrate 10 is made of, for example, soda glass, and has a length L1 and a width L2 of 2400 μm and 140 μm, respectively, in a portion corresponding to the long side of the outer peripheral portion of the display surface 12, as shown in FIG.
An electrode pad 14 for drain having a size of m is, for example, 14
Six pad groups G formed by arranging, for example, 160 pieces at an interval of 0 μm are arranged at appropriate intervals (only three groups are shown in the figure), and therefore, for example, 16 pad groups are provided on both long sides.
Zero electrode pads 14 are formed.

Further, for example, 480 electrode pads 14 for gates are formed on one short side of the outer peripheral portion of the display surface 12 at the same intervals as described above. The probing substrate 22 to be inspected for the LCD substrate 10 has the display surface 1 of the LCD substrate at the center thereof.
2 has an opening 26 of substantially the same size as
The probing substrate 22 has a large number of probe needles 20 according to the present invention arranged along the edge of the opening, a substrate 28 for holding and positioning the probe needles 20, and a substrate 28 for attaching and supporting the substrate 28. It is mainly configured by the support plate 30.

FIG. 4 is an explanatory view for explaining a mounting state of the probe needle, and FIG. 5 is an enlarged view of the probe needle shown in FIG. The probe needle 20 is set to have a diameter of, for example, 100 μm, which is made of, for example, cipher (trade name) in which tungsten or iron wire is plated with gold, and the LCD is used.
A large number are provided in the openings 32 of the substrate 28 in groups along the longitudinal direction thereof so as to correspond to the installation positions of the electrode pads 14 on the substrate. The angular probe needle group G1 is composed of 160 probe needles 20 like the pad group G described above, but in the illustrated example, only 5 probe needles 20 are shown for simplification.

The substrate 28 for positioning and fixing the probe needle 20 is made of a material having the same linear expansion coefficient as that of the LCD substrate 10, for example, soda glass, and the expansion and contraction amounts thereof due to the temperature change are substantially the same. I am doing it. Further, glass epoxy resin, aluminum or the like may be used as the material of the substrate 28. When attaching the probe needle 20, as shown in FIG. 7, first, a U-shaped groove 34 having a width L1 of, for example, about 110 μm is etched at a predetermined pitch at a corner of the opening end 32 of the substrate 28. And the like. At this time, the interval L2 between the grooves 34 is set to, for example, about 80 μm, and the depth of each groove 34 is set to a depth that allows the probe needle 20 to be completely accommodated in this groove. And, in particular, the depth L3 of the groove 34A at the lower end portion
Is much larger than the diameter of the probe needle, for example, about 400 μm, because the groove 34A regulates the lateral movement of the probe needle as described later.

The probe needle 20, which is a feature of the present invention and is formed in a substantially U shape along the inside of the grooves 34, 34A.
Is provided. Particularly, in this embodiment, the probe needle 2
For example, a protruding bent portion 20B having a radius of 0.5 mm is formed at the lower end portion of the vertical portion 20A of 0, and the bent portion 20B is bent by approximately 90 degrees so that an elastic force can be applied to the bent portion 20B. ing. Then, in a portion extending from the bent portion 20B in the horizontal direction, the upper end is widened and bent downward in a substantially convex shape so that the lower end is in a substantially horizontal state, and the length L4 is about 1 m.
A horizontal contact portion 20C of about m is formed, and the horizontal contact portion 20C forms an electrode pad 14 having a length of about 2.4 mm.
Is configured to be in line contact with the surface of the. And
Probe needle tip 2 extending beyond the horizontal contact portion 20C
0D is provided below the bottom of the groove 34A at the lower end so as to have a free end so that this part also has an elastic force, and is applied to the horizontal contact part 20C at the time of contact with the electrode pad 14. A part of the pressing force is absorbed, and the guiding force can be regulated upward so as not to shift laterally.

The vertical portion 20 of the probe needle 20
On the front side of A, a pressing plate 38 made of the same material as the substrate 28 is stretched along the longitudinal direction of the substrate 28. As a result, the groove 34 facing the front side is configured as the guide hole 40. Further, a supporting plate 30 for supporting the entire probing substrate is attached to the upper portion of the substrate 28 over the entire surface. The support plate 30
An elastic member such as an elastomer may be interposed between the substrate 28 and the substrate 28 so that a uniform pressing force can be applied at the time of contact. Further, the base portion of each probe needle 20 is connected to a signal line 42 (see FIG. 1) by a pogo pin or the like having a spring incorporated therein, which is not shown, and each signal line is connected to a tester 44. The LCD substrate 10 is configured to be inspected via 40.

Further, as shown in FIG. 2, the LCD substrate 1
On the upper part of the base 24 on which 0 is placed, a Z-axis adjusting mechanism 46 that is vertically movable to adjust Z (vertical direction),
Similar to the Y-axis adjusting mechanism 48 for adjusting the Y (vertical direction) direction, for example, a Y-axis adjusting mechanism 48 having a screw shaft or a nut driven by a stepping motor, and for adjusting the X (horizontal direction) direction. X-axis adjustment mechanism 50
Are sequentially provided, and a fixed plate 52 is provided on the X-axis adjusting mechanism 50. And this fixed plate 52
A rotatable disk-shaped θ plate 53 for adjusting the θ axis is provided on the upper side of the L plate 53.
The CD substrate 10 is placed and fixed. In addition, these X, Y,
The adjustment mechanism for each axis of Z and θ may be provided on the probing substrate side instead of the base 24 side. Further, as shown in FIG. 1, the LCD substrate 10 is provided with, for example, a cross-shaped alignment mark 54, and the substrate 28 of the probing substrate 22 is provided with a portion corresponding to the mark 54. A peep window 56 containing a CCD camera or a microscope is formed.

Next, the operation of this embodiment configured as described above will be described. First, the LCD substrate 10 is used as the base 2
4 is attached and fixed to the θ plate 53, and the probing substrate 22 provided on, for example, an elevating table is lowered from above to bring the horizontal contact portion 20C of the probe needle 20 to the LCD substrate 10.
To contact the electrode pad 14 of. At the time of this contact operation, each adjustment mechanism on the base 24 side is operated while gazing at the mark 54 of the LCD substrate 10 from the observation window 56 of the probing substrate 22 with a CCD camera or the like, and X, Y, Z, θ.
Adjust each axis of, and bring them into close contact with each other gradually. Then, a high-frequency voltage of a predetermined frequency is applied to the electrode pads 14 of the LCD substrate 10 from the tester 44 via the probe needles 20, and the LCDs are collectively inspected.

In this case, in this embodiment, since the probe needle 20 is provided with the horizontal contact portion 20C, this portion is linearly formed on the electrode pad 14 which is formed relatively long. That is, so-called line contact is made, and unlike the conventional point contact, the contact resistance can be significantly reduced. That is, when the horizontal contact portion 20C is brought into contact with the probe needle 20, the bendable portion 20B having elasticity is formed on the probe needle 20 as shown in FIG. 8 and the probe needle tip 20D is a movable free end. At the same time as the contact with the electrode pad 14, the horizontal contact portion 20C is bent to the bent portion 20B.
And the probe needle tip 20D contacts the bottom of the groove 34A at the lower end and moves so as to slide slightly horizontally, resulting in the horizontal contact portion 20C. Comes into elastic contact with the electrode pad 14, and the horizontal contact portion 20C of the probe needle 20.
It is possible to absorb the variation in the space between the electrode pad 14 and the electrode pad 14 and perform reliable line contact with a uniform pressure, and to significantly reduce the contact resistance. The uniformity of the contact pressure can be further improved when an elastomer is provided between the support plate 30 and the substrate 28.

Since the probe needle 20 and the electrode pad 14 are brought into line contact with each other as described above, dust from scratches formed by the line contact is not generated, and
It is also possible to improve the yield. In addition, in this embodiment, the probe needle 20 of the probing substrate 22 is used.
Since the substrate 28 for positioning and fixing is made of a material forming the LCD substrate 10, for example, a material having the same linear expansion coefficient as that of soda glass, for example, soda glass which is the same material, the size of the LCD substrate is 450 mm
Even if the size is increased to × 450 mm, the amount of expansion and contraction due to changes in the environmental temperature of both members is almost the same, and therefore the probe needle 2
When 0 and the electrode pad 14 corresponding thereto are not displaced, it is possible to bring them into contact with each other reliably.

Although the probe needle tip 20D is a free end in the above embodiment, the present invention is not limited to this. As shown in FIG. 9, the probe needle tip 20D is bonded to the substrate by an adhesive 60 such as a bond. Adhesively fixed to the groove bottom of the lower end of 28,
It may be configured as a fixed end. In this case, since the elastic force of the horizontal contact portion 20C of the probe needle 20 may be insufficient to some extent, a uniform contact pressure at the time of contact between the substrate 28 and the support plate 30 is ensured. It is preferable to interpose an elastic member, for example, the elastomer 62.

Further, in the above embodiment, the collective type probing substrate which is brought into contact with the entire LCD substrate 10 at a time has been described, but the present invention is not limited to this, and the conventional structure as shown in FIG. 11, for example. The probe needle having the horizontal contact portion according to the present invention may be applied as the probe needle in the divided type probing substrate. Further, as shown in FIG. 10, a pair of split-type probing substrates 22A, 22A to which the probe needle 20 according to the present invention is applied are provided to face each other along both long sides of the LCD substrate 10, and the probing substrates 22A are provided. , 22A are connected by a connecting plate 66, and the connecting plate 66 is connected to the LC plate.
The pair of guide rails 68, 68 provided along the longitudinal direction of the D substrate 10 may be moved by a screw screw 72 rotated by, for example, a stepping motor 70 as a drive source. Further, in order to contact the electrode pad for the gate of the LCD substrate 10, a probing substrate 22B to which the probe needle 20 according to the present invention is applied is provided on the side corresponding to one edge of the LCD substrate 10. .. Although the LCD substrate has a quadrangular shape in the above embodiments, the present invention is not limited to this, and the present invention is applicable to LCDs having a triangular shape or other shapes.
Of course, it can be applied to a substrate.

[0022]

As described above, according to the present invention, the following excellent operational effects can be exhibited. Since the probe needle and the electrode pad are brought into line contact with each other, the contact resistance at the time of inspection can be greatly reduced, and therefore the inspection result can be stabilized and accurate inspection can be performed. .. In addition, since scratches due to contact do not occur, it is possible to suppress dust generation and improve product yield.

[Brief description of drawings]

FIG. 1 is a perspective view showing a probing substrate using a probe needle according to the present invention.

FIG. 2 is a plan view of the probing substrate shown in FIG.

FIG. 3 is an enlarged plan view showing electrode pads of an LCD substrate.

FIG. 4 is an explanatory diagram for explaining a mounting state of a probe needle.

5 is an enlarged view of the probe needle shown in FIG.

6 is a side view of the probe needle shown in FIG.

7 is a cross-sectional view of a mounting portion of the probe needle shown in FIG.

FIG. 8 is an operation explanatory view showing the operation of the probe needle shown in FIG. 7.

FIG. 9 is a diagram showing a modification of the probe needle of the present invention.

FIG. 10 is a plan view showing another probing substrate to which the probe needle according to the present invention is applied.

FIG. 11 is a side view for explaining a probe needle of a conventional probing substrate.

FIG. 12 is a plan view for explaining a probe needle of a conventional probing substrate.

[Explanation of symbols]

 10 LCD board 12 Display surface 14 Electrode pad 20 Probe needle 20A Vertical part 20B Bent part 20C Horizontal contact part 20D Probe needle tip 22 Probing board 28 Board 34 Groove 34A Lower end groove 38 Presser plate 42 Signal line 44 Tester 46 Z-axis adjustment Mechanism 48 Y-axis adjusting mechanism 50 X-axis adjusting mechanism 53 θ plate 60 Adhesive 62 Elastomer G Pad group G1 Probe needle group

Claims (1)

[Claims] 1. A probe needle provided on a probing substrate and contacting an electrode pad of the liquid crystal display substrate for inspecting the liquid crystal display substrate, wherein the probe needle is the pad for making line contact with the pad. A probe needle having a horizontal contact portion made parallel to the probe needle.