JP3633776B2 - Inspection and correction methods for substrates for plasma display panels - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention, disconnection of electrodes wiring board for a plasma display panel, inspecting a short circuit, to a method of modifying.
[0002]
[Prior art]
In recent years, plasma display panels (hereinafter also referred to as PDPs) are being used in various display devices because of their thin depth, light weight, and clear display and wider viewing angle than liquid crystal panels.
In general, a plasma display panel (PDP) has a structure in which a pair of regularly arranged electrodes are provided on two opposing glass substrates, and a gas mainly composed of neon, xenon, or the like is enclosed therebetween. Then, a voltage is applied between these electrodes, and discharge is generated in minute cells around the electrodes, thereby causing each cell to emit light for display. In particular, in order to display information, the regularly arranged cells are selectively discharged to emit light.
[0003]
Here, the configuration of the PDP will be described with an example of the AC type PDP shown in FIG.
FIG. 5 is a perspective view of the PDP structure, but the front plate (glass substrate 510) and the back plate (glass substrate 520) are shown separated from each other for the sake of clarity.
As shown in FIG. 5, two glass substrates 510 and 520 are arranged in parallel and facing each other, and both are barriers (cell barriers) provided in parallel to each other on a glass substrate 520 serving as a back plate. (Also referred to as 530).
A composite electrode composed of a transparent electrode 540 as a discharge sustaining electrode and a metal electrode 550 as a bus electrode is formed in parallel with each other on the back side of the glass substrate 510 as a front plate. A layer 560 is formed, and a protective layer (MgO layer) 570 is further formed thereon.
In addition, address electrodes 580 are formed on the front side of the glass substrate 520 serving as a back plate so as to be perpendicular to the composite electrode and between the barriers 530 in parallel with each other. A fluorescent surface 590 is provided so as to cover.
The barrier 530 is for partitioning the discharge space, and each partitioned discharge space is called a cell or a unit light emitting region.
This AC type PDP is a surface discharge type, and has a structure in which an AC voltage is applied between the composite electrodes on the front plate to cause discharge. In this case, since alternating current is applied, the direction of the electric field changes corresponding to the frequency. The phosphor 590 emits light by the ultraviolet rays generated by this discharge, and the observer can visually recognize the light transmitted through the front plate. The DC type PDP is different from the AC type in that the electrode has a structure not covered with a dielectric layer, but the discharge effect is the same.
5 has a structure in which a base layer 567 is provided on one surface of a glass substrate 520 and a dielectric layer 565 is provided thereon, but the base layer 567 and the dielectric layer 565 are not necessarily required. .
[0004]
Since the manufacturing process of the back plate and the front plate of such a plasma display panel (PDP) substrate is complicated and long, defects occur in the manufacturing process, and various inspections are performed during and after manufacturing. In particular, inspection of disconnection and short-circuiting of electrode wiring is indispensable to assure the final quality of the back plate and the front plate.
Conventionally, inspecting the electrode wiring on the back plate and the front plate of the plasma display panel (PDP) substrate such as disconnection and short circuit, for example, using a probe as shown in FIG. As shown in (2), there has been known an electrical continuity test method in which each wiring is examined for whether each wiring is disconnected or whether there is a short circuit with an adjacent wiring.
This method is also called a probe inspection method. Basically, an operation of applying a voltage between two predetermined locations and confirming the presence or absence of conduction between the two locations is performed in the same wiring and adjacent two wirings. Therefore, this operation is performed for all the wirings to be inspected. There are various shapes for the flow.
Here, a method for inspecting the electrode wiring 440 (441, 442) using the probe shown in FIG. 4A will be described.
In order to make the explanation easy to understand, the electrode wiring 440 is arranged in a straight line at a predetermined pitch, and the interval between the needles (415 in FIG. 4 (a)) is substantially equal to the pitch of the electrode wiring 440. A case where inspection is performed using two probes each having a probe card will be given.
As shown in FIG. 4B, first, the both ends of the electrode wiring 440 are brought into contact with the probe terminals 410A and 410B of the probes, respectively. The needle P1 of the probe card 410 and the needle P2 of the probe card 410B are both in contact with the wiring 411, and the needle of each probe card is in contact with the adjacent wiring in sequence. In this state, by selecting a predetermined two needles, a predetermined one needle of the probe card 410A and a predetermined one needle of the probe card 410B, applying a voltage between the two needles and checking the voltage between them, It is possible to know the disconnection or conduction state between two needles.
That is, if the two hands P1 and P2 shown in FIG. 4B are designated, the presence or absence of disconnection of the wiring 441 can be confirmed. If the two hands P1 and P3 are designated, the presence or absence of conduction between the adjacent wiring 441 and wiring 442 is confirmed. Can be confirmed.
Actually, the designation of the two needles to be inspected is performed by sequentially changing (scanning) by a detection unit (not shown). Then, the obtained voltage waveform is processed by the processing unit to detect the presence / absence of disconnection of wiring and the presence / absence of conduction between adjacent wirings.
In this manner, the presence / absence of disconnection of the wiring and the presence / absence of conduction between the adjacent wirings are detected for all the electrode wirings in the region (1).
Next, for all the wirings in the area {circle around (2)}, the probe card 410A is moved in the direction of the arrow until P1 reaches the position of P5, the probe card 410B is moved in the direction of the arrow, and P2 is in the position of P6. Until each needle touches the wire.
When the probe cards 410A and 410B are moved, the one end needle is separated from the wiring.
As described above, the presence / absence of disconnection of wiring and the presence / absence of conduction between adjacent wirings are detected for all the wirings in the area (2).
In this way, the inspection method using the probe card, in this way, each of the two probes is in a direction perpendicular to the wiring at a predetermined pitch corresponding to the number of probe terminals (number of needles) and the pitch between the needles. The inspection is performed for all the wirings in the entire board while sequentially feeding.
[0005]
As another inspection method, there is known a defect extraction method for extracting shape defect position coordinates of electrode wiring over the entire inspection target region by performing image processing on image data of a sample obtained by an imaging unit. This method is also called an image processing inspection side, Briefly, the process of extracting a portion Recessed difference image data or we deleted obtained by comparing the image data the aspirations of the adjacent electrode wiring, the design rule to based captured image data, sequentially, erosion processing, dilation processing, or sequentially, expansion processing, by comparing the image data and the original photographed image data obtained by performing erosion processing and processing for extracting a defect portion It is used together.
[0006]
In the inspection by the probe inspection method, there is a drawback that the quality of the shape cannot be inspected simply by inspecting continuity and short circuit.
Further, in the inspection in the image processing inspection method, the quality of the shape can be inspected, but it is difficult to extract a short circuit in a state close to transparency or a disconnection with a very small width.
For this reason, for example, a first inspection, a correction method, or a probe that performs inspection by the probe inspection method and inspection by the image processing method on the entire inspection target region of the sample and corrects a defective portion obtained from both inspections. Inspect the entire inspection target area of the sample by the inspection method, extract the disconnection or short-circuit defect location, further inspect only the extracted location by the image processing inspection method, and correct only the defect location to be corrected The second inspection and correction method was adopted.
In the first inspection and correction method, the defect extraction including the shape defect is more reliable than the second method, but there is a problem that it takes an inspection time.
In the second method, since the inspection by the image processing inspection method is performed only on the portion extracted by the inspection by the probe inspection method, there is an advantage that the inspection time can be reduced as compared with the first inspection method. However, shape defect extraction is not sufficient.
In addition, since both the first method and the second method are corrected after the inspection by the probe inspection method and the inspection by the image processing method, the final quality assurance for the state after the correction cannot be performed.
For this, the probe inspection may be performed again after the correction, but the inspection and correction process becomes complicated.
[0007]
[Problems to be solved by the invention]
As described above, in the inspection and correction methods for disconnection, short circuit, and other shape defects of the electrode wiring provided on the substrate for the conventional plasma display panel, it is efficient without complicating the entire inspection and correction process. In particular, there has been a demand for an inspection and correction method capable of correcting defects to be corrected including shape defects on the entire inspection target area.
The present invention responds to the mass production of plasma display panels, which are becoming larger and more miniaturized, and inspects for the disconnection, short circuit, and other shape defects of the electrode wiring provided on the plasma display panel substrate. An object of the present invention is to provide an inspection and correction method that can efficiently and reliably correct defects to be corrected including shape defects on the entire inspection target area.
[0008]
[Means for Solving the Problems]
The method for inspecting and correcting a plasma display panel substrate according to the present invention is a method for inspecting and correcting disconnection and short-circuiting of electrode wirings provided on a substrate for a plasma display panel. A defect extraction step of extracting defect position coordinates over the entire inspection target region by performing image processing on the photographed image data of the sample obtained, and (b) disconnection, short circuit, and others that can be corrected among the extracted defect locations a correcting step for correcting a defective shape, (c) electrically disconnection of the electrode wire, to have a electrical continuity inspection step of inspecting the presence or absence of a short circuit, the defect extraction step, the adjacent electrode wires image a process of extracting data same aspirations Recessed difference image data or it deleted obtained by comparing the position, with respect to captured image data on the basis of the design rule, successively shrinking process, the expansion process or sequence Rise Process, is characterized in that in which a combination of the process of extracting the defect portion by comparing the image data and the original photographed image data obtained by performing contraction processing.
Further, in the above, the electrical continuity inspection step is to perform inspection for presence / absence of conduction in each electrode wiring and inspection for presence / absence of conduction between adjacent electrode wirings using a probe. Is.
In addition, the defect in a defect extraction process means a shape defect, and here, the defect which does not become a disconnection, a short circuit, and a disconnection and a short circuit, and a convex defect are made into a shape defect.
[0009]
[Action]
The inspection and correction method for the plasma display panel substrate of the present invention has such a configuration, thereby inspecting the disconnection, short circuit, and other shape defects of the electrode wiring provided on the plasma display panel substrate, In the correction method, it is possible to provide an inspection and correction method that can efficiently and reliably correct defects to be corrected including shape defects on the entire inspection target region.
As a result, it is possible to cope with the mass production of plasma display panels that are becoming larger and cells are becoming finer.
Specifically, sequentially, (a) a defect extraction step of extracting defect position coordinates over the entire area to be inspected by performing image processing on the captured image data of the sample obtained by the imaging means, and (b) extracted A correction process for correcting disconnection, short circuit, and other shape defects that can be corrected among the defective portions, and (c) an electrical continuity inspection process for electrically inspecting the presence or absence of disconnection or short circuit of each electrode wiring. This is achieved by being. I.e., by image processing the image data of the sample obtained by the imaging means, by performing the defect extraction step of extracting a defect position coordinates over inspected entire region, disconnection, Ru can extract short defect and shape defects It is said. And, after performing a correction process that corrects disconnection, short circuit, and other shape defects that can be corrected among the extracted defect locations, an electrical continuity inspection process is performed to correct or correct defects detected. It is possible to prevent the outflow of the substrate that cannot be performed downstream of the process.
[0010]
The image processing of the image data of the photographed sample in defect extraction process, specifically, the captured image signal after capturing converted A / D, compares the captured image data the aspirations of the adjacent electrode wirings a process of extracting the obtained difference image data or et defect portion with respect to the captured image data on the basis of the design rule, successively shrinking process, the expansion process or sequentially, expansion processing, image data obtained by performing erosion processing you combination with a process for extracting a defective portion by comparing the original photographed image data and. As the electrical continuity inspection process, using the probe 400 as shown in FIG. 4 (a), to inspect the presence or absence of conduction between the inspection, and electrode wiring for each adjacent presence or absence of conduction at each electrode in the wire A method is mentioned.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a method for inspecting and correcting a substrate for a plasma display panel according to the present invention will be described.
FIG. 1 is a flowchart showing an example of the embodiment, FIG. 2 is a diagram showing an example of an electrode wiring pattern, and FIG. 3 is a schematic configuration diagram for explaining a photographing method.
The inspection / correction method shown in FIG. 1 is an inspection / correction method for disconnection or short circuit of electrode wiring provided on a substrate for a plasma display panel.
Then, in order, (a) a defect extraction step of extracting defect position coordinates over the entire inspection target region by performing image processing on the captured image data of the sample obtained by the imaging unit, and (b) the extracted defect location among possible modifications, breakage, is to perform a short circuit, and a correcting step of correcting the other defective shape, and an electrical continuity inspection step of inspecting the presence or absence of disconnection, short-circuit (c) electrically each electrode wiring .
[0012]
First, as shown in FIG. 1, an electrode wiring provided on one surface of a back plate (glass substrate) is photographed by an imaging means, and the obtained image data is subjected to image processing, whereby a defective shape of the electrode wiring is regarded as a defect. Extract. (S110)
Here, the disconnection, the short circuit, and the concave defect and the convex defect that do not become the disconnection or the short circuit are extracted.
As shown in FIG. 3, the imaging is performed using an imaging means 310 such as a line sensor (or area sensor) using a CCD element or the like by applying illumination light 320A from the back side of the sample (back plate) 370, as shown in FIG. By moving the back plate 370) and the imaging means 310 relatively, the entire inspection region of the sample 370 is imaged with the transmitted light 320B, and the captured image signal obtained by each imaging is A / D converted. Obtained as photographed image data, processed by the image processing unit 340, and defect extraction is performed. Note that in order to capture the entire inspection region, the imaging is usually performed while moving the sample 370 in a predetermined direction (thick arrow direction) by the transfer unit 330, but the imaging timing is performed by the encoder 380.
In FIG. 3, 300 is an imaging inspection apparatus, 310 is imaging means, 320 is illumination means, 320A is illumination light, 320B is transmitted light, 321 is a diffuser, 330 is a transfer unit, 340 is an image processing unit, and 350 is A monitor, 360 is a control unit, 370 is a back plate, 380 is an encoder, 381 is a signal detection head, and 385 is a signal detection unit.
For example, the electrode wiring has a pattern as shown in FIG. For this reason, with respect to the stripe portion 223 that can be handled as a periodic pattern, a defective portion can be extracted by comparing between image data corresponding to adjacent electrode wirings.
For terminal portions (also referred to as drawer portions) (225 in FIG. 2) that cannot be treated as periodic patterns, the image data obtained by shooting are subjected to shrinkage processing and expansion processing sequentially or based on design rules. By sequentially performing expansion processing and contraction processing (also referred to as design rule check (DRC) processing) and comparing the obtained image data with the original photographed image data, a defective portion can be extracted.
In other words, with regard to shape defects such as disconnection, short circuit, concave defect, convex defect, etc., which are limited by the design rule, the short circuit and convex defect are subjected to shrinkage processing and expansion processing in order to obtain the shape from the captured image data Defects can be removed, and disconnection and concave defects are defect extraction utilizing the fact that shape defects can be removed from captured image data by sequentially performing expansion processing and contraction processing.
Note that the comparison between the image data referred to here is to obtain a difference image data by taking a difference in units of pixels, and the obtained difference image data is usually subjected to defect point emphasis processing such as differentiation processing. Thereafter, a defective portion is extracted by comparing with a predetermined defect detection level.
By obtaining the difference image data, the photographic image data contains a gradual signal change (shading) caused by uneven illumination, uneven sensitivity on the imaging surface, etc., or fixed unevenness based on photographing (based on dust adhering to the optical system, etc.) Local irregularities, etc.) are excluded. For random noise generated by a video signal circuit or the like, photographing at the same location is performed a plurality of times (N times), and each image data is added for each pixel and averaged to obtain image data at that location. Can be excluded. Random noise generated in a video signal or the like is 1 / N ^1/2 .
[0013]
Next, correction is performed as necessary on all the detected defective portions in this way. (S120)
In the case of the disconnection, the correction is performed by applying a conductive paste to the disconnection portion and firing it. Moreover, in the case of a short circuit, the process which removes the part is performed.
The shape defect portion is similarly adjusted to a predetermined shape.
[0014]
Next, the electrode wiring thus corrected is further inspected for disconnection and short circuit of each electrode wiring by a probe inspection method using the probe 410 as shown in FIG. 4 (S130), and the inspection result is OK ( Only those that are good) are passed to the next (downstream) process. (S140)
Then, if the inspection result is OUT (defect determination), it does not flow to the next (downstream) process and is determined as a defective product at that stage. (S145)
[0015]
For example, when the electrode wiring has a pattern as shown in FIG. 2, two probes are arranged at positions (1) and (2), and further arranged at (3) and (4). In the same manner as described in (b), the presence or absence of disconnection or short circuit of each wiring is inspected for all the inspection regions.
Needless to say, it is necessary to use probes at positions (1) to (4) according to the pitch of the wiring to be inspected. Further, depending on the pattern of the electrode wiring, the probes used for (1) and (2) can be used as probes at positions (4) and (3).
Note that the Y direction in FIG. 2 is a direction along the stripe portion 223, the X direction is a direction orthogonal to this, and a direction along the surface of the back plate (glass substrate) 2310. The probe at positions (1) to (4) is moved along the X direction for inspection.
[0016]
By inspecting and correcting in this way, it is possible to prevent a defective product from flowing into the next (downstream) process. That is, the generation of waste such as creating a PDP using a defective electrode wiring is eliminated.
[0017]
【The invention's effect】
The present invention, as described above, disconnection of the electrode wiring provided on a substrate for plasma display panel, the short-circuit test, in the modified method, efficiently, and reliably, to be corrected in the inspection areas over the entire surface It has become possible to provide inspections and correction methods that can correct defects. In particular, it is effective for substrates having electrode wirings for plasma display panels, which are becoming larger and cells are becoming increasingly finer. As a result, it is possible to cope with mass production of substrates for plasma display panels .
[Brief description of the drawings]
FIG. 1 is a flowchart of an example of an embodiment of the present invention. FIG. 2 is a diagram showing a pattern (pattern) of electrode wiring. FIG. 3 is a diagram for explaining an imaging method. FIG. 5 is a perspective view for explaining the PDP. FIG. 5 is a perspective view for explaining the PDP.
S110 to S145 Processing step 210 Back plate (glass substrate)
220 Electrode wiring 223 Stripe part 225 Terminal part (lead-in part)
300 imaging inspection apparatus 310 imaging means 320 illuminating means 320A illumination light 320B transmitted light 321 diffuser plate 330 transfer unit 340 image processing unit 350 monitor 360 control unit 370 back plate 380 encoder 381 signal detection head 385 signal detection unit 410, 410A, 410B Probe card 415 Needle (terminal)
415A Needle tip 440, 441, 442 Electrode wiring

Claims (2)

A method for inspecting and correcting disconnection and short-circuiting of electrode wirings provided on a substrate for a plasma display panel, wherein (a) inspection is performed by image processing of image data of a sample obtained by an imaging means. A defect extracting step for extracting defect position coordinates over the entire target area; (b) a correcting step for correcting disconnection, short circuit, and other shape defects that can be corrected among the extracted defect locations; and (c) electrical. disconnection of each electrode wiring, have a electrically conductive inspection process for inspecting the presence or absence of a short circuit, the defect extraction step, the adjacent electrode wires image data comrades defect from the difference image data obtained by comparing the location of the The image data obtained by performing the expansion process and the contraction process sequentially on the captured image data based on the design processing rule and the captured image data or the expansion process and the contraction process, and the original captured image A plasma display panel for inspection of the substrate, modified wherein the by comparing the over data in which a combination of the process of extracting the defect. The method for inspecting and correcting a plasma display panel substrate according to claim 1 , wherein the electrical continuity inspection step uses a probe to inspect the presence / absence of continuity in each electrode wiring and to conduct continuity between each adjacent electrode wiring. A method for inspecting and correcting a substrate for a plasma display panel, wherein the presence or absence is inspected.

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