JP2007114124A - Method and device for inspecting array substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inexpensively inspecting an array substrate that has incorporated a drive circuit, and to provide its device. <P>SOLUTION: In a drive state of a scanning line drive circuit 24 that has applied a drive current V<SB>DD-Y</SB>, a relay 112 is switched; and in respective cases where a resistor 110 is separated and in another case where the resistor is added, an electron beam is irradiated on an OLB pad 31 by an electron gun 104; and a potential difference ΔV<SB>eb-Y</SB>of the OLB pad 31 is detected from the difference between detection amounts of secondary electrons generated thereby. A current value I<SB>YD1</SB>, flowing when driving the drive circuit 24 is calculated, on the basis of expression I<SB>YD1</SB>=(ΔV<SB>eb-Y</SB>×V<SB>DD-Y</SB>)/[R<SB>st-Y</SB>×(V<SB>DD-Y</SB>-ΔV<SB>eb-Y</SB>)] from detected potential difference ΔV<SB>eb-Y</SB>, and electrical defect of the drive circuit is detected, depending on whether consumption current of the drive circuit 24 is in a prescribed range. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an array substrate inspection method and apparatus used in an active matrix type liquid crystal display device.

  In recent years, an active matrix type liquid crystal display device in which a TFT (thin film transistor) is arranged as a switching element for each pixel constituting a display screen has been widely spread because it is suitable for high definition without crosstalk between adjacent pixels. In particular, those using p-Si (polycrystalline silicon) TFTs as TFTs can integrate a driver circuit in addition to the pixel portion on the array substrate, thus facilitating wiring and miniaturizing the device. It is considered advantageous.

  By the way, after the manufacturing process of the array substrate is completed, the manufactured array substrate is inspected to prevent the defective array substrate from flowing into the next process. As an inspection method for such an array substrate, the voltage on the pixel electrode is detected by detecting secondary electrons emitted by irradiating each pixel with an electron beam, and the presence or absence of defective pixels in the display screen is inspected. Is known (see Patent Document 1). In this inspection method, when a p-Si array substrate with a built-in drive circuit is targeted, the potential on the pixel electrode can be measured without going through the drive circuit, so that defective pixels can be detected with high accuracy. .

However, in the inspection method using the electron beam described above, the pixel can be inspected, but the drive circuit cannot be inspected, and the test pattern is input from the input / output terminals formed on the array substrate. It is necessary to inspect the drive circuit with an electrical driver tester. Therefore, when inspecting an array substrate with a built-in drive circuit, an EB (Electron Beam) tester that irradiates an electron beam and detects secondary electrons must be used in combination with an electrical tester. There is a problem that the cost required increases. Further, when the EB tester and the electrical tester are used in combination, there are problems such as a decrease in processing capability due to a communication time lag between the two testers and a complicated processing of measured data.
JP 2000-3142 A

  The present invention has been made in view of the above problems, and an object thereof is to provide an array substrate inspection method and apparatus capable of reducing the cost required for inspection of an array substrate having a built-in pixel portion and drive circuit. To do.

  According to an array substrate inspection method of the present invention, a pixel TFT including a pixel TFT disposed at each intersection of a plurality of scanning lines and a plurality of signal lines and a pixel electrode connected to each pixel TFT, and driving the pixel section And an input terminal for supplying power from an external power supply to the signal line drive circuit. In the array substrate inspection method, the drive power is supplied from the external power supply to the drive circuit via the input terminal. In the supplied state, the input terminal is irradiated with an electron beam to emit secondary electrons, and the secondary potential is detected to obtain first potential information; and between the external power source and the input terminal In the state where driving power is supplied to the driving circuit from the external power source via the resistor and the input terminal with a resistor interposed between them, the input terminal is irradiated with an electron beam to emit secondary electrons, and the secondary power is emitted. By detecting electrons, the second power Comprising a step of obtaining information, and characterized by detecting an electrical failure of the drive circuit based on a potential difference of the input terminals that is calculated from the first potential information and the second electric potential information.

  According to the present invention, since the pixel portion and the drive circuit can be inspected by the EB tester, the electrical tester is not required, and the cost required for the inspection can be reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing an array substrate 10 to be inspected in an embodiment of the present invention. The array substrate 10 has a plurality of scanning lines 12 for scanning on an insulating substrate 11 such as a glass substrate. A plurality of signal lines 14 for video signals intersecting with these scanning lines 12, and p-Si pixels as switching elements in the vicinity of the intersections where these scanning lines 12 and the signal lines 14 intersect. A TFT (hereinafter referred to as a pixel TFT) 16 is provided. Each pixel TFT 16 has a source terminal connected to the signal line 12, a drain terminal connected to the pixel electrode 18, and a gate terminal connected to the scanning line 12. Each pixel electrode 18 is connected to one end of the auxiliary capacitor 20, the other end of each auxiliary capacitor 20 is connected to the auxiliary capacitor line 22, and a display area 19 is formed on the array substrate 10.

  Further, a drive circuit 23 that controls the pixel TFT 16 and supplies a video signal to the pixel electrode 18 through the signal line 14 is formed at the end on the array substrate 10. More specifically, the drive circuit 23 is arranged outside the scan line drive circuit 24 provided at one end of the scan line 12, the signal line selection circuit 26 provided at one end of the signal line 14, and the array substrate 10. And a signal line driving circuit including a video signal supply circuit (not shown). The scanning line driving circuit 24 controls the pixel TFT 16 by supplying a scanning signal to the scanning line 14. On the other hand, in the signal line driving circuit, the video signal supplied from the video signal supply circuit is supplied to the signal line 16 selected by the signal line selection circuit 26.

  Further, OLB pads 31 to 39 for inputting power, logic signals and the like necessary for the operation of the scanning line driving circuit 24 and the signal line selection circuit 26 in the driving circuit 23 are included at the edge of the array substrate 10. An OLB pad group 30 is provided. Specifically, the OLB pads 31 and 32 are connected to the power supply terminal of the scanning line driving circuit 24, and the OLB pad 33 is connected to the signal input terminal of the scanning line driving circuit 24. The OLB pads 34 and 35 are connected to the power supply terminal of the signal line selection circuit 26, and the OLB pad 36 is connected to the signal input terminal of the signal line selection circuit 26. The OLB pad 37 is connected to all the auxiliary capacitance lines 22 through the wiring 28 provided on the array substrate 10.

  Next, a method for inspecting the array substrate 10 configured as described above by the EB method will be described.

  As shown in FIG. 2, the EB tester 100 used for this inspection includes a power / signal input / output unit 102 that supplies various test signals and power to the array substrate 10 to be inspected, and an electron beam to the array substrate 10. An electron gun 104 for irradiation and a detector 106 for detecting secondary electrons emitted by irradiation with an electron beam are provided.

The power / signal input / output unit 102 is connected to the probing pad group 40 connected to the OLB pad group 30 via a probe (not shown), and supplies various test signals and voltages to the array substrate 10. . More specifically, the power / signal input / output unit 102 supplies a predetermined power supply voltage YV _DD to the probing pad 41 connected to the OLB pad 31 via a relay 112 that can be switched between addition and disconnection of the resistor 110. , A predetermined power supply voltage YV _SS is supplied to the probing pad 42 connected to the OLB pad 32, and control for controlling the scanning line driving circuit 24 such as a clock signal and a horizontal synchronization signal to the probing pad 43 connected to the OLB pad 33 is performed. The signal Y _DATA is supplied.

Further, the power / signal input / output unit 102 supplies a predetermined power supply voltage XV _DD to the probing pad 44 connected to the OLB pad 34 via the relay 116 capable of switching between addition and disconnection of the resistor 114, and the OLB pad. A predetermined power supply voltage XV _SS is supplied to the probing pad 45 connected to the control signal 35, and a control signal X _DATA for controlling the signal line selection circuit 26 such as a clock signal and a video signal is supplied to the probing pad 46 connected to the OLB pad 36. It comes to supply.

The power supply / signal input-output unit 102, so as to supply a predetermined auxiliary capacitance voltage V _CS to the probing pad 47 connected with the OLB pads 37 via the relay 120 capable of switching between addition and disconnection of the resistor 118 It has become.

  Furthermore, the power / signal input / output unit 102 is connected to the electron gun 104 and the detector 106, and supplies control signals and power to them. Thus, the electron gun 104 is controlled to irradiate the array substrate 10 with the electron beam, and the electron gun 104 scans the entire array substrate 10 or irradiates a specific portion on the array substrate 10 with the electron beam. The power source / signal input / output unit 102 receives electrical potential information from the detector 106 and detects an electrical failure site in the array substrate 10 based on the electrical potential information.

When inspecting the scanning line driving circuit 24, first, the relay 112 is disconnected from the resistor 110, and power is supplied from the power source / signal input / output unit 102 to the scanning line driving circuit 24 via the OLB pads 31 and 32. At the same time, the control signal Y _DATA is input via the OLB pad 33, so that the scanning line driving circuit 24 is brought into a normal driving state. In this state, when the electron gun 104 irradiates the OLB pad 31 with an electron beam, secondary electrons corresponding to the potential of the OLB pad 31 are generated, and the amount of secondary electrons detected by the detector 106 is reduced to the first level. It is detected as potential information (see FIG. 4). At this time, the current I _YD1 flowing in the scanning line driving circuit 24 is given by the following equation (1). Here, V _DD is a voltage value of the power supplied from the signal / power generation unit 102 to the scanning line driving circuit 24, and a potential difference (YV _DD −YV _SS ) applied to the OLB pad 31 and the OLB pad 32. _RYD is an internal resistance value of the scanning line driving circuit 24.

I _YD1 = V _DD / R _YD formula (1)
Next, the relay 112 is switched and the resistor 110 is interposed between the probing pad 41 and the power / signal input / output unit 102, and similarly to the above, the power and control signal Y _DATA are supplied to the scanning line driving circuit 24. Then, the electron gun 104 irradiates the OLB pad 31 with an electron beam, and the amount of secondary electrons detected by the detector 106 is detected as second potential information (see FIG. 4). At this time, the current I _YD2 flowing in the scanning line driving circuit 24 is given by the following equation (2). Here, R _ST-Y is the resistance value of the resistor 110.

I _YD2 = V _DD−Y / (R _YD + R _ST−Y ) Formula (2)
Next, as shown in FIG. 4, the potential difference ΔV _eb−Y of the OLB pad 31 in each case is detected from the difference in the detected amount of secondary electrons when the resistor 110 is disconnected and when the resistor 110 is added. Since this potential difference ΔV _eb−Y corresponds to the amount of voltage drop due to the addition of the resistor 110, the relationship between the potential difference ΔV _eb−Y , the current I _YD2 and the resistance value R _ST−Y is expressed by the following equation (3). Is established.

I _YD2 = ΔV _eb−Y / R _ST−Y formula (3)
By substituting the equations (2) and (3) into the equation (1), the following equation (4) is obtained. Based on this equation (4), the current that flows when the scanning line driving circuit 24 is driven from the potential difference ΔV _eb−Y. The value I _YD1 can be detected, whereby it is possible to check whether or not the consumption current of the scanning line driving circuit 24 is within a predetermined range.

I _YD1 = (ΔV _eb−Y × V _DD−Y ) / [R _ST−Y × (V _DD−Y −ΔV _eb−Y )] Formula (4)
The signal line selection circuit 26 can be inspected by the same method as that for the scanning line selection circuit 24 described above. That is, in the driving state in which the power supply and the control signal _XDATA are input to the signal line selection circuit 26, the relay 116 is switched, and the electron beam is applied to the OLB pad 34 in each of the cases where the resistor 114 is disconnected and added. Irradiation is performed, and the potential difference ΔV _eb−X of the OLB pad 34 is detected from the difference in the detected amount of secondary electrons generated thereby. By substituting the detected potential difference ΔV _eb−X into the following formula (5), the current value I _XD1 that flows when the signal line selection circuit 26 is driven can be detected. It can be checked whether the current is within a predetermined range. In the following formula (5), V _DD-X is a voltage value of the power supplied from the signal / power generation unit 102 to the scanning line driving circuit 24 and is applied to the OLB pad 34 and the OLB pad 35. This corresponds to a potential difference (XV _DD −XV _SS ), R _XD is an internal resistance value of the signal line selection circuit 26, and R _ST-X is a resistance value of the resistor 114.

I _XD1 = [ΔV _eb−X × V _DD−X ] / [R _st−X × (V _DD−X −ΔV _eb−X )] Formula (5)
Furthermore, the defect of the auxiliary capacitor 20 and the short circuit of the auxiliary capacitor line 22 can be inspected by the same method as in the scanning line selection circuit 24 described above, and the auxiliary capacitor voltage V _CS is input to the auxiliary capacitor 20. In this state, the relay 118 is switched and the OLB pad 37 is irradiated with an electron beam in each of the case where the resistor 120 is disconnected and the case where the resistor 120 is added, and the OLB pad is determined from the difference in the detected amount of secondary electrons generated thereby. The potential difference ΔV _eb−CS of 37 is detected. In a normal state where there is no defect in the auxiliary capacitor 20 and no short circuit of the auxiliary capacitor line 22, no current flows between the signal / power supply generation unit 102 and the auxiliary capacitor 20, and therefore no potential difference ΔV _eb−CS occurs. On the other hand, if there is a defect in the auxiliary capacitor 20 or if the auxiliary capacitor line 22 is short-circuited, a leak current is generated, and a potential difference ΔV _eb-CS is generated.

Next, in order to inspect the pixel unit 19, the power / pixel is supplied from the signal / power generation unit 102 to the scanning line driving circuit 24 and the signal line selection circuit 26 via the probe 108, the probing pad group 40 and the OLB pad group 30. A control signal for inspecting the unit 19 is input, and a predetermined auxiliary capacitance voltage _VCS is input to the auxiliary capacitance line 20. Thereby, each pixel electrode 18 of the pixel unit 19 is scanned so that a predetermined voltage is sequentially applied, and in synchronization with this, the electron gun 104 irradiates each pixel electrode 18 with the electron beam and emits secondary electrons. Is detected by the detector 106, the voltage value of each pixel electrode 18 can be detected, and it can be inspected whether the pixel portion 19 has a defect.

  As described above, in the array substrate inspection method according to the present embodiment, since the pixel unit and the drive circuit can be inspected by the EB tester 100, an electrical tester is not necessary, and the cost required for the inspection can be reduced. it can.

It is the schematic which shows the array board | substrate made into test object in one Embodiment of this invention. It is the schematic which shows the inspection method of the drive circuit of an array board | substrate. It is a figure which shows the detection amount of the secondary electron at the time of the test | inspection of a drive circuit.

Explanation of symbols

10 ... Array substrate 12 ... Scanning line 14 ... Signal line 16 ... Pixel TFT
DESCRIPTION OF SYMBOLS 18 ... Pixel electrode 19 ... Pixel part 23 ... Drive circuit 24 ... Scan line drive circuit 26 ... Signal line selection circuit 100 ... EB tester 102 ... Power supply / signal input / output part 104 ... Electron gun 106 ... Detector 110, 114 ... Resistance 112 116 ... Relay

Claims (7)

A pixel TFT disposed at each intersection of a plurality of scanning lines and a plurality of signal lines; a scanning line driving circuit for supplying scanning signals to the scanning lines; and a signal line driving circuit for supplying video signals to the signal lines; An inspection method for an array substrate comprising: an input terminal for supplying power from an external power source to the scanning line driving circuit and the signal line driving circuit,
In a state in which driving power is supplied from the external power source to the driving circuit through at least one of the scanning line driving circuit and the signal line driving circuit through the input terminal, the input terminal is irradiated with an electron beam to perform secondary operation. Obtaining first potential information by emitting electrons and detecting the secondary electrons;
In the state where a drive power is supplied from the external power supply to the drive circuit via the resistor and the input terminal by interposing a resistor between the external power supply and the input terminal, the input terminal is irradiated with an electron beam. A step of emitting secondary electrons and obtaining second potential information by detecting the secondary electrons,
An inspection method for an array substrate, comprising: detecting an electrical failure of the drive circuit based on a potential difference between the input terminals calculated from the first potential information and the second potential information.   2. The array substrate inspection method according to claim 1, wherein the drive circuit is formed on the array substrate. A drive current value _ID flowing through the drive circuit in a state in which drive power is supplied from the external power supply to the drive circuit via the input terminal is calculated from the following formula, and the drive is calculated based on the drive current value _ID. 3. The method for inspecting an array substrate according to claim 1, wherein an electrical failure of the circuit is detected.
I _D = ΔV _eb × V _DD / [R _st × (V _DD −ΔV _eb )]
Here, ΔV _e is a potential difference of the input terminal, V _DD is a voltage value of the driving power source supplied to the driving circuit by the external power source, and R _st is a resistance value of a resistor interposed between the external power source and the input terminal.   4. The array substrate inspection method according to claim 1, wherein the driving circuit is the scanning line driving circuit.   4. The array substrate inspection method according to claim 1, wherein the drive circuit is the signal line drive circuit.   The signal line driving circuit includes a video signal supply circuit that outputs a video signal, a signal line selection circuit that supplies a video signal from the video signal supply circuit to a signal line selected from a plurality of signal lines, and The array substrate inspection method according to claim 1, wherein the signal line selection circuit is formed on the array substrate. A pixel TFT disposed at each intersection of a plurality of scanning lines and a plurality of signal lines; a scanning line driving circuit for supplying scanning signals to the scanning lines; and a signal line driving circuit for supplying video signals to the signal lines; An array substrate inspection apparatus for inspecting an array substrate having an input terminal for supplying power from outside to the scanning line driving circuit and the signal line driving circuit,
Power supply means for supplying drive power to the drive circuit via the input terminal;
Switching means for switching whether or not to interpose a resistor between the power supply means and the input terminal;
When the drive power is supplied to the drive circuit, the secondary electron is emitted by irradiating the input terminal with an electron beam in each of the case where the resistor is disconnected and the case where the resistor is added, and the secondary electron is detected. Detecting means for acquiring potential information by doing,
A failure analysis means for detecting an electrical failure of the drive circuit based on a potential difference of the input terminal calculated from the potential information;
An inspection apparatus for an array substrate, comprising:

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