JPH0634392B2 - Inspection device for transparent electrodes - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent electrode inspection device, and in particular, a transparent electrode pattern indispensable for electronic devices used in various fields such as liquid crystal panels, EL panels, plasma panels and solar cells. Of the inspection device.

2. Description of the Related Art Conventionally, as a method for inspecting a transparent electrode, there has been a so-called visual inspection in which the surface of a substrate on which a transparent electrode is formed is observed using an optical microscope. For example, the pattern placed on the sample stage of the optical microscope is sequentially moved to inspect the pattern, or the surface of the substrate is observed by a video camera integrated with the optical microscope and displayed on the TV screen. The quality of the transparent electrode pattern was visually determined. Although the above visual observation is effective for observing a small area, for example, over a large area of A4 size,
Moreover, when observing a monotone striped repeating pattern, visual errors are likely to occur frequently. In addition, when dust is present on the substrate surface, it is often difficult to distinguish it from a pattern defect. As a transparent electrode pattern inspection apparatus that solves such a problem, the present applicant has proposed an apparatus that determines the quality of a pattern using infrared rays. (Japanese Patent Application No. 59-157269) Problems to be Solved by the Invention Although the new inspection device described above is very effective against an inspection error, which is a visual problem, the time and accuracy required for the inspection are reduced. Not enough in terms. The present invention has been made in view of the above points, and an object of the present invention is to provide a further improved transparent electrode inspection apparatus capable of inspecting a transparent electrode on a substrate in a short time with high accuracy.

Means for Solving the Problems In order to solve the above problems, the present invention irradiates a substrate on which a plurality of stripe-shaped transparent electrodes are formed with infrared rays, the transparent electrodes for the infrared rays, and The transparent electrodes and a plurality of infrared light detecting elements provided correspondingly between the electrodes so as to detect transmitted light or reflected light between the electrodes, respectively, and maintain the appropriate distance from the substrate. An infrared light line sensor arranged to intersect the transparent electrode, and transmission of the infrared ray from the transparent electrode and between the electrodes at an arbitrary position of the substrate using the infrared light line sensor. A means for detecting light or reflected light and storing the output value of the line sensor, and a similar detection at a position slightly displaced in the stripe direction of the transparent electrode from the arbitrary position, And a means for calculating a difference value and an average value by comparing the output value of the line sensor and the stored value for the transparent electrode and the electrode, respectively, and corresponding to the transparent electrode. It is configured to detect a disconnection of the transparent electrode by the difference value, a short circuit of the transparent electrode by the difference value corresponding to the electrodes, and a resistance value of the transparent electrode by the average value corresponding to the transparent electrodes. A device for inspecting a transparent electrode is provided.

Action The present invention, by virtue of the above configuration, the transmission and reflectance of infrared rays are different between the substrate and the transparent electrode, and the fact that the transmission and reflectance are also different depending on the resistance value of the transparent electrode is utilized. A transparent electrode and means for detecting and storing transmitted light or reflected light between the electrodes, and means for comparing a detection value at a new measurement point with the stored value and calculating a difference value and an average value That is, a disconnection occurs due to the difference value of the detection outputs corresponding to the transparent electrodes, a short circuit occurs due to the difference value of the detection outputs corresponding to the electrodes, and a resistance value of each transparent electrode depends on the average value of the detection outputs corresponding to the transparent electrodes. Each is accurately detected in a short time.

Embodiment FIG. 1 is a block diagram showing an embodiment of the transparent electrode inspection apparatus of the present invention. In FIG. 1, reference numeral 1 denotes a glass substrate, which is used as a transparent electrode for indium tin oxide (hereinafter referred to as ITO).
A plurality of ITO electrodes 2 are formed in stripes. An infrared light source 3 having a wavelength of 2 μm is provided on the glass substrate 1 so as to irradiate the glass substrate 1 with infrared rays, and the ITO electrode 2 and the space between the electrodes are placed 5 mm below the glass substrate 1. An infrared light line sensor 5 provided with a large number of infrared light detecting elements 4 so as to detect the transmitted infrared rays respectively corresponding to the respective electrodes and between the respective electrodes is installed orthogonally to the ITO electrodes. There is. Using this infrared light line sensor 5, a timing control circuit 6
Thus, the transmitted infrared light from the ITO electrode 2 on the glass substrate 1 and between the electrodes is detected at a proper timing, the output of the detection element 4 is amplified by the amplifier 7, and the value is stored in the memory circuit 8. Next, the glass substrate 1 is moved by 100 μm in the horizontal direction along the stripe of the ITO electrode 2 by the substrate drive circuit 9, the same detection is performed, and the output of the detection element 4 is amplified by the amplifier 7.
Is amplified and compared with the output value stored in the memory circuit 8, the differential value is calculated by the differential amplifier 10, and the average value is calculated by the average value circuit 11. In this example, the infrared ray having a wavelength of 2 μm was transmitted through the glass substrate 1 only at a rate of 90%, and the ITO electrode 2 on the glass substrate 1 was transmitted at a rate of 7%. Therefore, regarding the ITO electrode, when there is no disconnection in the ITO electrode 2, the difference value is equal to 0, and in the case of disconnection, an output appears and disconnection detection 11 is performed. Regarding the output corresponding to the electrodes, the difference value increases only when the ITO electrode 2 is short-circuited with the adjacent ITO electrode 2, and the short-circuit detection 12 is performed. In this way, since the disconnection and the short circuit are determined by the difference value rather than the absolute value of the infrared detection output, regardless of, for example, the film quality of the ITO electrode 2, the pattern width, or the variation in the infrared transmittance of the glass substrate between the substrates. It has the merit of being able to inspect. Regarding the resistance value of the ITO electrode 2, for example, as shown in FIG.
There is a dependency between the infrared ray transmittance of μm and the film resistance value. Therefore, if the infrared ray transmittance is calibrated in advance, the resistance value can be known from the transmittance.
In the apparatus of the present embodiment, the previous detection value and the new detection value stored in order to improve the accuracy are input to the average value circuit 11, the average value is calculated, and the electrode resistance detection 13 is performed based on this value. In the same manner, the glass substrate 1 was moved by controlling the substrate driving circuit 9 with good timing by the timing control circuit 6, and the transparent electrodes on the entire surface of the substrate could be inspected.

As described above, by using the transparent electrode inspection apparatus according to the present invention, it is possible to reproducibly and quickly inspect the transparent electrode on the substrate for disconnection, short circuit and resistance. In the embodiment of the present invention, the transmitted light of the infrared ray is used, but of course, the effect does not change even if the configuration detects the reflected light. The wavelength of the infrared light source is 2 μm in this embodiment.
However, the optimum wavelength is determined by the type of substrate on which the transparent electrode is formed, or whether infrared light is used for transmission or reflection, but quartz glass is used as the substrate. When utilizing the transmission of infrared rays, a wavelength of 5 μm or less was suitable. Further, in this embodiment, the substrate is moved with respect to the infrared ray detection system, but it goes without saying that the substrate may be fixed and the infrared ray detection system may be moved.

EFFECTS OF THE INVENTION As described above, the transparent electrode inspection device of the present invention is
The disconnection, short circuit, and detection of the resistance value of the transparent electrode on the substrate can be reproduced with high accuracy over the entire surface of the substrate with high accuracy, regardless of the variation between the substrates and in a short time.

[Brief description of drawings]

FIG. 1 is a block diagram of a transparent electrode inspection apparatus showing an embodiment of the present invention, and FIG. 2 is a diagram showing a relationship between a resistance value of an ITO film and an infrared ray transmittance. 1 ... Glass substrate, 2 ... ITO electrode, 3 ... Infrared light source, 4 ... Infrared light detecting element, 5 ... Infrared light line sensor, 10 ... Differential amplification circuit.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Yosuke Fujita 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Tomizo Matsuoka, 1006 Kadoma, Kadoma City, Osaka 72) Inventor Atsushi Abe 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 61-38406 (JP, A) JP 55-85210 (JP, A) JP A 55-87431 (JP, A)

Claims (3)

[Claims] 1. A means for irradiating a substrate on which a plurality of stripe-shaped transparent electrodes are formed with infrared rays, and means for detecting transmitted light or reflected light between the transparent electrodes and the electrodes of the infrared rays, respectively. An infrared light detecting element provided corresponding to each of the transparent electrodes and between the electrodes, the infrared light being arranged so as to intersect the transparent electrode while maintaining an appropriate distance from the substrate. An optical line sensor and the infrared light line sensor are used to detect transmitted light or reflected light of the infrared ray from the transparent electrode and between the electrodes at an arbitrary position of the substrate, and an output value of the line sensor. The same detection is performed at a position slightly displaced in the stripe direction of the transparent electrode from the arbitrary position, and the output value of the line sensor at that time and the stored value are stored. And a means for calculating a difference value and an average value by respectively comparing the transparent electrodes and the electrodes respectively, and disconnecting the transparent electrodes by the difference values corresponding to the transparent electrodes, between the electrodes. An inspection apparatus for a transparent electrode, characterized in that a short circuit of the transparent electrode is detected by the difference value corresponding to, and a resistance value of the transparent electrode is detected by the average value corresponding to the transparent electrode. 2. The transparent electrode inspection apparatus according to claim 1, wherein the wavelength of infrared rays is 5 μm or less. 3. The transparent electrode inspection apparatus according to claim 1, wherein the transparent electrode is made of at least a transparent conductive film containing an oxide of In.