JPH03116012A - Detecting method for adjacent short-circuit defective part - Google Patents

Abstract

PURPOSE:To shorten the time for detecting a short-circuit defective part by deriving a position of a short-circuited part, based on a measured resistance value, a resistance value between both ends of each electrode, and length, as for each adjacent electrode which is decided to be short-circuited. CONSTITUTION:As for a short circuit of an adjacent electrode 2, a resistance value between the adjacent electrodes 2 is decided to be lower than usual, and this resistance value is proportional to a distance Xa extending from end part in which it is measured from a short-circuit part 5. Also, length of the electrode is proportional to the short- circuit part, and a resistance between both ends of the electrode is in inverse proportion thereto. Accordingly, based on the resistance value between these adjacent electrodes, and the length and the resistance value between both ends of the electrode, a position of the short-circuit part is derived. That is, when length of the electrode, a resistance value between both ends of the electrode, and a resistance value between adjacent electrode in one end are denoted as l, RE and RS, respectively, and a position of the short-circuit part is denoted by a distance (x) extending from one end thereof to the short-circuit part, the position (x) of the short-circuit part is calculated from an expression I. In such a way, the manhour of an inspection process and a restoration process of a substrate can be decreased.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for detecting adjacent short-circuit defects in an electrode pattern formed on a substrate, and in particular to a method for detecting adjacent short-circuit defects in an electrode pattern formed on a substrate, and in particular for detecting a group of electrodes formed in a stripe shape on a liquid crystal cell substrate or the like. The present invention relates to a method for detecting adjacent short-circuit defects.

[Prior Art] Very closely spaced stripe patterns are formed on the substrate of a matrix liquid crystal cell, but with the recent trend toward higher definition and larger screens, there are cases where more than a thousand stripes are formed on one substrate. In such cases, for each striped electrode that must exist in an electrically insulated state, there is a high rate of defects such as short-circuits and disconnections with adjacent electrodes during the manufacturing process. It is not possible to avoid the process of making the product non-defective using the repair method used. Conventionally, only good or defective products were selected by electrical means, and defective parts were detected by automated equipment using visual inspection or pattern recognition.

[Problems to be Solved by the Invention] However, in the conventional inspection method, when visually searching for repairable adjacent short-circuit defects on a defective board, an operator must detect adjacent short-circuited striped electrodes. It was necessary to catch up visually from the end, and it took a lot of time to detect the defective part.

Additionally, automated equipment that uses pattern recognition can
Since the resolution of defective parts of several μm is required, there are also drawbacks such as a large amount of time being wasted.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for detecting adjacent short-circuit defects, which greatly reduces the time required to detect short-circuit defects.

[Means for Solving the Problems] To achieve the above object, the method for detecting adjacent short-circuit defects of the present invention provides a method for detecting adjacent short-circuit defects between adjacent electrodes at at least one end of a plurality of striped electrodes formed close to each other on a substrate. The presence or absence of a short circuit between adjacent electrodes is determined by measuring the resistance value of the electrode, and for each adjacent electrode that is determined to be short-circuited, the measured resistance value and the resistance value and length between both ends of each electrode are determined. Based on this, the position of the short part is determined.

For example, for each adjacent electrode that has been determined to be short-circuited, the length of the electrode is ρ, the resistance value between both ends of the electrode is RE, the resistance value between adjacent electrodes at one end is R8, and the position of the shorted part is defined as this one end. If it is expressed as the distance MX from to the short part, then the position X of the short part is puX= ・R8 2R.

It is calculated as

[Operation] In this configuration, a short circuit between adjacent electrodes is determined as a resistance value between the adjacent electrodes that is lower than normal, and this resistance value is proportional to the distance from the end where it is measured to the short portion. Further, the length of the electrode is proportional to the distance to the shorted part, and the resistance between both ends of the electrode is inversely proportional. Therefore, the position of the short portion is determined based on the resistance value between these adjacent electrodes and the length and resistance value between both ends of the electrodes.

More specifically, when striped electrodes of the same shape are formed, the wiring resistance values R7 of adjacent electrodes are almost equal, and the distribution of conductivity that occurs during the formation of a conductive film and dimensional variations during patterning. etc., occur between large areas on the board. Considering this, the first
As shown in the figure, adjacent short-circuited electrodes are expressed and discussed using an equivalent circuit. In the figure, γ8 is the resistance of the short-circuit defect. For example, if we consider the case of the electrode of a matrix liquid crystal cell, the electrode with the short-circuit defect is ITO.
Even in the case of an electrode, the adjacent short resistance value R8 can be almost expressed as Rs J=rR2+R4, and it can be considered that R2=R4. Therefore, between the length l of the electrode from one end to the other end and the length X from one end to the defective part,
This value can be used as an extremely effective value for finding defective parts.

[Example] Hereinafter, the present invention will be explained in detail using the drawings.

As shown in Figure 2 above, the ITO electrode 2 has a length 1 of 250 mm''1 and a pole width a of 0.3 mm, so that the distance between the electrodes is 0.
．． A glass substrate 1 having a plurality of stripes of 0.01 mm in diameter was prepared, and the resistance value from one end of one electrode 2 to the other end was measured with a multimeter 3, and it was found to be 3.2 Ω. Ta.

Next, one end of the manual blower needles 4a and 4b was brought into contact with the adjacent electrodes 2, and the resistance value between each adjacent electrode 2 was sequentially measured using the multimeter 3. Adjacent 74 without short defects. The electrode gap showed high insulation of 10 MΩ or more, but the short resistance value R5 between the electrodes with a short defect was 6 to 0 at the maximum. The values of this short resistance value R5 are shown in Table 1 for four defective parts (Example 1-4).

Next, the short defect portion 5 of the electrode 2 having these defects is found using a microscope, and the short defect portion 5 is
The distance from one end of the electrode to taX.

was measured. On the other hand, for the same electric 8i2, the distance to the short defective part! It was detected by calculating xb using the above equation (1).

These results are expressed as the error ΔX (=X,
-Xb) are shown in Table 1.

As shown in Table 1, it can be seen that, according to the method of the present invention, values extremely close to the values up to the short defect portion determined by actual observation were obtained. Furthermore, the distance at
x b with laser repair machine (NEC 5L-432)
By manually moving the coordinates to the position, it becomes possible to repair short-circuit defects faster than before.

As shown in FIG. 3, a substrate 1 similar to that in Example 1 is prepared, and two blower probes 4a, 4b, and 4c, 4d are contacted at both ends of the electrodes 8i2e and 2f, for example. First, turn on only switches 6a and 6d to increase the wiring resistance value RE of electrode 2f.
, = 3.18. Next, switches 6b and 60
The wiring resistance R, , = 3.18 when the voltage is turned on is 52
I found Ω. Thereafter, only switches 6a and 6b were turned on to obtain a short resistance value Rs+ = 3.785 kΩ, and only switches 6C and 6d were turned on to measure short resistance value R52 = 2.597 Ω. The resistance molecule of the short-circuit defect portion 5 was calculated from these resistance values, and the following was obtained. From this result, the distance to the defective part is 111
x was calculated and obtained.

This value also showed an accurate value for the actual defect location.

[Effects of the Invention] As explained above, according to the present invention, by simply measuring the resistance between adjacent electrodes and the resistance between both ends of the electrodes, it is possible to immediately detect not only the presence or absence of a short-circuit defect but also its position. The number of steps for inspecting and repairing the substrate on which the striped electrodes are formed can be significantly reduced. Furthermore, it becomes possible to create a device that integrates inspection and repair functions.

[Brief explanation of drawings]

FIG. 1 is an electrical equivalent circuit diagram of an electrode with an adjacent short defect to explain the detection method of the present invention, and FIG. 2 shows how a short defect is detected in the first embodiment of the present invention. FIG. 3 is a perspective view of the substrate shown, and FIG. 3 is a plan view of the substrate showing how a short circuit defect is detected in the second embodiment of the present invention. 1. Glass substrate, 2: ITO stripe electrode, 3: Multimeter 4a, 4b, 4c. 4d: Manual blowbare needle, 5: Mt! Short defective part, 6a, 6b, 6c, 6d switch.

Claims (2)

[Claims] (1) Measure the resistance value between adjacent electrodes at at least one end of multiple striped electrodes formed close to each other on the substrate to determine whether there is a short circuit between the adjacent electrodes, and if there is a short circuit, A method for detecting an adjacent short defect portion, characterized in that, for each determined adjacent electrode, the position of the short portion is determined based on the measured resistance value and the resistance value and length between both ends of each electrode. (2) For each adjacent electrode that is determined to be short-circuited, the length of the electrode is l, the resistance value between both ends of the electrode is R_E, the resistance value between adjacent electrodes at one end is R_S, and the position of the shorted part is 2. The method for detecting an adjacent short defective part according to claim 1, wherein the position x of the short part is calculated as x=(l/2R_E)·R_S when expressed by the distance x from one end to the short part.