JP2006194787A - Sensor, inspection device, and inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly sensitive and highly precise sensor, an inspection device, and an inspection method. <P>SOLUTION: A sensor electrode 20 is made of an ITO film, an electrically conductive film and made to function as a reception electrode via electrostatic coupling in-between with pixel electrodes on a panel. A gate metal 23 is formed below a gate electrode 51. By connecting the sensor electrode 20 to one end part of the gate metal 23 via a contact 43, the connection between a CMOS element 41 and the sensor electrode 20 is secured. As a result, it is possible to electrically connect the sensor electrode 20 to the gate electrode 51 of the CMOS element 41 without depending on production processes of the gate electrode 51. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to, for example, a sensor, an inspection apparatus, and an inspection method that can inspect the quality of a liquid crystal panel and a liquid crystal display substrate.

  With the demand for thinner and larger displays such as television receivers and personal computers, liquid crystal display panels with a high pixel count have been developed, and products that use them are on the market. In a product employing such a thin and large display device, it is important to inspect the display alone as well as an operation test after the product is assembled.

  As a method for inspecting a display substrate such as a liquid crystal display panel, a probe is brought into contact with each of a gate wiring and a source wiring connected to a TFT transistor provided corresponding to each pixel in a conventionally known method. There is one that determines the presence or absence of a defect in the pixel electrode from the output voltage.

  On the other hand, in the inspection method using the probe as described above, problems such as frequent contact failure and increased probe replacement cost are caused by the narrowing of the pixel pitch accompanying the full color and high definition of the liquid crystal display. It was. In view of such problems, for example, in the liquid crystal panel inspection apparatus disclosed in Patent Document 1, a thin array sensor is arranged on a substrate, an amplifier and a scanner are provided adjacent to the array sensor, and the space between them is set. In addition, a lead wire for forming a metal film is wired to the array sensor so as to be close to the liquid crystal panel to be inspected, thereby improving the detection level and S / N ratio in the non-contact inspection. This array sensor incorporates a potential sensor using a field effect transistor. An example is shown in FIG.

  In FIG. 5, the liquid crystal panel 116 includes a glass substrate 117 and pixel electrodes 118, and a distance d between the glass substrate 117 and the unit transistor layer 5N is 20 μm. The potential sensor 1N applies an FET function, and a drain electrode D, a source electrode S, and a gate electrode G are formed in the unit transistor layer 5N. When a signal 111 is applied to the pixel electrode 118, a pixel voltage having a constant value is generated unless the pixel electrode 118 is disconnected. Therefore, by applying the command signal 113 for starting inspection, the gate electrode G is electrostatically connected to the pixel electrode facing the potential sensor via the capacitance C in the space according to the distance d. As a result, a current is generated between the drain electrode D and the source electrode S, and a potential sensor signal 2N is generated.

  Further, in Patent Document 2, a switch element including a source electrode, a semiconductor, and a drain electrode is arranged on the inspection substrate so as to face the image electrodes arranged on the liquid crystal display substrate, and the inspection substrate is brought close to the pixel electrode. Thus, a technique is disclosed in which a field effect transistor is formed by a semiconductor, a source electrode, a drain electrode, and a pixel electrode, and the pixel electrode acts as a gate electrode of the field effect transistor.

  In the potential sensor described in Patent Document 3, when the sensor is brought close to the pixel electrode of the liquid crystal display and inspected for non-contact quality, the gate terminal of the enhancement type MOS-FET is connected to the panel to be inspected via the air gap. It is connected to the upper pixel electrode.

Japanese Patent Laid-Open No. 11-153637 Japanese Patent Laid-Open No. 10-62474

JP 2001-133487 A

  However, the sensor used in the conventional inspection method described above, for example, the potential sensor described in Patent Documents 1 and 2, causes the pixel electrode of the liquid crystal panel to be inspected to act as the gate of the field effect transistor, and the wiring is obtained from the pixel voltage. Disconnection or short circuit is detected. For this reason, the sensitivity of the sensor becomes insufficient depending on the process of forming the field effect transistor, and there is a problem that the inspection result is not reliable.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a sensor, an inspection apparatus, and an inspection method with high sensitivity and high inspection accuracy.

  As a means for achieving this object and solving the above-mentioned problems, for example, the following configuration is provided. That is, the present invention is a sensor for detecting an inspection signal applied to an inspection object, and is connected to a MOS transistor formed on a substrate and a gate terminal of the MOS transistor formed on the substrate. And a means for outputting the inspection signal detected by the conductor film, wherein the substrate is a semiconductor substrate, a glass substrate, or a plastic substrate.

  For example, the conductor film is a film made of a refractory metal having a predetermined area. For example, the refractory metal contains at least ITO, IZO, aluminum, or tungsten.

  For example, the deposition area of the conductor film is at least 10 times the deposition area of the gate terminal. For example, the conductor film functions as a receiving electrode through capacitive coupling with the inspection object. For example, the inspection signal is detected from the inspection object in a non-contact manner through capacitive coupling between the conductor film and the inspection object.

  As another means for achieving the above object and solving the above-described problems, for example, the following configuration is provided. That is, the inspection apparatus according to the present invention includes a line sensor in which a plurality of the sensors according to the present invention are continuously arranged.

  As another means for solving the above-described problem, the inspection method according to the present invention is characterized in that the state of the inspection object is inspected in a non-contact manner using the inspection apparatus according to the invention.

  According to the present invention, the sensor sensitivity can be dramatically increased and the quality of the inspection target can be determined at high speed.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. As an inspection object by the sensor according to the present embodiment, in the following description, a plurality of pixel electrodes and thin film transistors (TFTs) for driving them are arranged in an array (or matrix) on a glass substrate. An example is a liquid crystal display panel or a touch panel having an arrayed structure. However, the inspection target is not limited to such an example. Here, since the inspection is performed in a non-contact manner, the sensor is positioned at a predetermined distance from the liquid crystal panel, and the quality of the pixel electrode formed on the liquid crystal panel is inspected based on the output from the sensor. To do.

  FIG. 1 schematically shows a configuration of a sensor circuit in which a plurality of sensors according to this embodiment are arranged. As shown in FIG. 1, the sensor circuit 31 of this embodiment is connected to a plurality of CMOS elements (MOS field effect transistors) 41 each having a sensor electrode 20 and a gate terminal (G) of the CMOS element 41. The sensor electrode 20 is a conductor film having a predetermined area and made of a high melting point metal (for example, ITO, IZO, aluminum, tungsten, etc.).

  The source terminal (S) of each CMOS element 41 is connected to the ground (GND) of the sensor circuit, and the drain terminal (D) of each element is connected to, for example, a signal processing unit of an inspection apparatus (not shown). In the sensor circuit 31, the distance L between the centers of the sensor electrodes 20 arranged in parallel is, for example, 70 μm and the pitch width is 50 μm.

  Next, the circuit pattern of the sensor according to the present embodiment will be described in detail. FIG. 2 shows an example of a circuit pattern of the sensor according to the present embodiment. In FIG. 2, only a circuit pattern of two sensors among a plurality of sensors is shown for simplicity, and the others are omitted. Also, illustration of a substrate on which these patterns are formed (for example, a semiconductor substrate, a glass substrate, a plastic substrate, a quartz substrate, etc.) is omitted.

  In the sensor shown in FIG. 2, the sensor electrode 20 is formed of, for example, ITO, IZO, aluminum, tungsten, or the like as a conductive film (oxide film). In the sensor circuit 31, the sensor electrode 20 is formed on a panel to be inspected. It functions as a receiving electrode (that is, an antenna) through electrostatic coupling (capacitive coupling) with the formed pixel electrode. Therefore, in order to ensure the connection between the CMOS element 41 and the sensor electrode 20, a gate metal 23 having a larger area is formed under the gate electrode 51, and the sensor is connected to one end of the gate metal 23 via a contact 43. The electrode 20 is connected.

  By doing so, the sensor electrode 20 having a predetermined area and having a high degree of freedom can be electrically connected to the gate electrode 51 of the CMOS element 41 without depending on the process of forming the gate electrode 51 in the CMOS element 41. Can be connected. The sensor electrode 20 has an area that is at least 10 times the area of the gate electrode 51.

  The source electrode 53 of the CMOS element 41 is connected to the ground line (GND) 21 of the sensor circuit 31 by a contact 45, and the drain electrode 55 is a signal of an inspection device (not shown) via a predetermined wiring shown in FIG. It is connected to the processing unit.

  FIG. 3 is a flowchart showing a manufacturing process of the sensor according to the present embodiment. In step S1 of FIG. 3, a gate metal and a ground metal are formed, and in subsequent step S3, a wiring pattern of the gate electrode 51 and the ground 21 is formed. For these pattern formations, for example, a photolithography method common in semiconductor technology is used.

  In step S5, for example, patterning of the source electrode 53 and the drain electrode 55 is performed using a photolithography method, and in step S9, in order to form the sensor electrode 20 described above, a high level of ITO, IZO, aluminum, tungsten, or the like is used. Film formation with a melting point metal is performed. In step S11, the sensor electrode 20 is patterned so as to have the pitch width described above.

  In step S13, a contact pattern (via hole) 43 for connecting the sensor electrode 20 to the gate electrode 51 (gate metal 23) of the CMOS element 41 and a source electrode 53 for connecting to the ground (GND) 21 of the sensor circuit. The contact pattern 45 is formed.

  FIG. 4 shows an example of the configuration (arrangement state of each sensor) of the line sensor including the sensors according to the present embodiment. The line sensor 1 shown in FIG. 4 is, for example, a one-dimensional structure configured such that a plurality of sensors 5 are alternately arranged with a constant pitch width, and has the same width as the liquid crystal panel 10 to be inspected as a whole. It is a line sensor. More specifically, it is a one-dimensional line sensor that inspects and determines the presence or absence of disconnection of a pixel electrode on a liquid crystal panel to be inspected by a sensor 5 in a non-contact manner. Further, the liquid crystal panel 10 is supplied with inspection signals necessary for inspection of individual pixel electrodes from a signal supply source (not shown).

  The sensor 5 needs to be arranged close to the pixel electrode in order to detect the potential (pixel voltage) of the inspection signal applied to the pixel electrode in a non-contact manner. Therefore, in the line sensor 1 shown in FIG. 4, in order to make the distance between the upper surface of the sensor 5 and the pixel electrode, for example, 100 μm or less, one end portion of the sensor 5 is brought into close contact with the spacer 33, and Try to be high.

  As described above, a conductor plate having a predetermined area, for example, a sensor electrode made of a conductor film such as ITO, IZO, aluminum, tungsten or the like is connected to a gate terminal (G) of a CMOS element (field effect transistor), By causing the sensor electrode to function as a receiving electrode (antenna) through electrostatic coupling with the pixel electrode, the sensor sensitivity can be dramatically increased. Further, by causing the sensor electrode to act as a gate of a field effect transistor, high-speed inspection can be performed with simple control.

  Further, by providing a sensor electrode connected to the gate terminal separately from the gate terminal of the CMOS element itself, the inspection accuracy for the inspection object does not depend on the process of forming the field effect transistor. As a result, the degree of freedom of the sensor shape is increased, and variations in sensor performance are eliminated, so that the quality of the inspection object can be reliably selected, and the quality can be easily and quickly determined.

It is a figure which shows typically the structure of the sensor circuit comprised with the sensor which concerns on the example of embodiment of this invention. It is a figure which shows the circuit pattern of the sensor which concerns on the example of embodiment. It is a flowchart which shows the manufacturing process of the sensor which concerns on the embodiment. It is a figure which shows the structural example of the line sensor comprised with the sensor which concerns on the example of embodiment. It is a figure which shows the structure of the electric potential sensor in the conventional liquid crystal panel test | inspection apparatus.

Explanation of symbols

1 Line Sensor 5 Sensor 15 Pixel Electrode 20 Sensor Electrode 24 Signal Processing Board 31 Sensor Circuit 33 Spacer 41 CMOS Element 43 Contact 51 Gate Electrode 53 Source Electrode 55 Drain Electrode

Claims (8)

A sensor for detecting an inspection signal applied to an inspection object,
A MOS transistor formed on a substrate;
A conductor film formed on the substrate and connected to a gate terminal of the MOS transistor;
Means for outputting the inspection signal detected by the conductor film,
The sensor is a semiconductor substrate, a glass substrate, or a plastic substrate. The sensor according to claim 1, wherein the conductor film is a film made of a refractory metal having a predetermined area. 3. The sensor according to claim 2, wherein the refractory metal contains at least ITO, IZO, aluminum, or tungsten. 4. The sensor according to claim 3, wherein the film formation area of the conductor film is at least 10 times the film formation area of the gate terminal. The sensor according to claim 4, wherein the conductive film functions as a receiving electrode through capacitive coupling with the inspection target. 6. The sensor according to claim 5, wherein the inspection signal is detected from the inspection object in a non-contact manner through capacitive coupling between the conductor film and the inspection object. An inspection apparatus comprising a line sensor in which a plurality of the sensors according to claim 1 are continuously arranged. An inspection method for inspecting a state of an inspection object in a non-contact manner using the inspection apparatus according to claim 7.

Images