JP2013108854A - Wiring defect inspection method and wiring defect inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring defect inspection method and apparatus which can identify even preliminary defects by heat generation inspection.SOLUTION: A wiring defect inspection apparatus 100 is configured to: apply voltage in a wiring path in a semiconductor substrate to short-circuit preliminary short-circuit defects which have not been short-circuit defects yet; maintain a state without voltage applied for prescribed time; apply voltage to the semiconductor substrate to generate heat and raise temperature in portions including the short circuit defects in or between wires; and image the semiconductor substrate with an infrared camera.

Description

  The present invention relates to a wiring defect inspection method and a defect inspection apparatus suitable for detecting defects in wiring formed on a semiconductor substrate such as a liquid crystal panel or a solar battery panel.

  A manufacturing process of a semiconductor substrate (for example, a liquid crystal panel) is roughly divided into an array (TFT) process, a cell (liquid crystal) process, and a module process. Among these, in the array process, after the gate electrode, the semiconductor film, the source / drain electrode, the protective film, and the transparent electrode are formed on the transparent substrate, the array inspection is performed, and the short circuit of the wiring such as the electrode or the wiring Existence is checked.

  Usually, in the array inspection, such a defect is identified by bringing a probe into contact with the end portion of the wiring and measuring the electrical resistance at both ends of the wiring or between the adjacent wirings. However, even if the presence or absence of a defect in the wiring portion can be detected in the array inspection, it is not easy to specify the position of the defect.

  For example, as a method for improving the above problem and specifying the position of the defect, a voltage is applied to the leaky defect substrate to generate heat, and the defect position is specified using an image obtained by imaging the surface temperature of the leaky defect substrate with an infrared camera. There is an infrared inspection.

  Patent Document 1 relates to an infrared inspection for detecting a short-circuit defect of a substrate by an infrared image. By using a difference image of an infrared image of a substrate before and after applying a voltage, a wiring that generates heat is detected, and a defect position is disclosed. To be able to identify.

JP-A-6-207914 (Publication date: July 26, 1994)

  However, in the detection method of Patent Document 1, there is a possibility that a defect reserve army that is short-circuited but not completely short-circuited may be missed, and a defect may flow out to a subsequent process. This is because a defect reserve army that is short-circuited but not completely short-circuited may grow into a true defect when a voltage for heat generation inspection is applied. This is because heat generation is started after this time, and there is a case where heat generation does not occur sufficiently within a predetermined voltage application time. That is, when determining whether or not to apply a voltage based on a resistance inspection result as in Patent Document 1, it is highly likely that a substrate having only a defective reserve arm will end up with an inspection result of “good” (that is, no defect). There is a possibility of growing into a true defect in a later process.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a wiring defect inspection method and apparatus that can be specified by a heat generation inspection even if a defect reserve army.

Therefore, in order to solve the above problems, the wiring defect inspection method according to the present invention is:
A voltage is applied to the wiring provided on the semiconductor substrate to generate heat in the short-circuit path including the wiring short-circuit portion. Including a determination step for identifying
Prior to the determination step,
It includes a pretreatment step of applying a voltage to the wiring and maintaining a voltage non-application state for a predetermined time after the application.

  According to said structure, the short circuit preliminary | backup part which is a stage before a wiring short circuit part which becomes a wiring short circuit part if a voltage is applied can be made to grow into a wiring short circuit part by the voltage application by the said pre-processing process. For this reason, in the case where only the determination step is performed without performing the pretreatment step, the wiring including the short-circuit spare portion does not generate heat so that it is determined that there is a wiring short-circuit portion, and there is no wiring short-circuit portion. It is possible to avoid a situation in which it is erroneously determined and appears as a wiring short-circuit portion in the subsequent process due to voltage application. That is, according to the wiring defect inspection method according to the present invention, since the determination step is performed after the short-circuit spare portion is grown into the wiring short-circuit portion, there is an effect that accurate determination can be performed.

  Moreover, according to said structure, after applying a voltage and making a short circuit preliminary part grow into a wiring short circuit part in a pre-processing process, a voltage non-application state is maintained for a predetermined time. As a result, in the pretreatment process, the short circuit path (the short circuit path including the wiring short circuit part grown from the short circuit preparatory part) that has risen in temperature due to voltage application is cooled, and the wiring short circuit that originally existed at the start of the inspection by the infrared camera The temperature can be unified between the portion and the wiring short-circuit portion grown from the short-circuit spare portion. Therefore, the temperature rise by voltage application in the wiring short-circuit portion originally present and the wiring short-circuit portion grown from the short-circuit spare portion can be started under the same conditions. Therefore, accurate determination can be performed.

In addition to the above configuration, one aspect of the wiring defect inspection method according to the present invention is as follows.
Between the pretreatment step and the determination step, by measuring the resistance value of the wiring, including a resistance value measurement step of determining the presence or absence of a wiring short-circuit portion,
The determination process is as follows:
A voltage specified based on the resistance value measured in the resistance value measurement step is applied to a short-circuit path including the wiring short-circuit portion of the semiconductor substrate determined to have the wiring short-circuit portion in the resistance value measurement step. A heating step for generating heat in the short circuit path;
Shooting the short-circuit path that has generated heat in the heat generation step with an infrared camera, and specifying the position of the wiring short-circuit portion based on the information of the shooting,
It is preferable that it contains.

  According to said structure, by applying the voltage specified based on the resistance value acquired beforehand by the resistance test to the said semiconductor substrate, the emitted-heat amount in this semiconductor substrate becomes constant, and an infrared camera is used. The temperature rise can be reliably confirmed by infrared inspection, and the short circuit portion can be specified. Further, since the applied voltage is not too high to burn out the defective portion, the short-circuit portion can be identified stably.

Moreover, one form of the wiring defect inspection method according to the present invention is more specifically,
The voltage applied in the pretreatment step can be greater than or equal to the voltage applied in the determination step. As a result, the defect reserve army can be efficiently and reliably grown into a true defect.

Moreover, one form of the wiring defect inspection method according to the present invention is more specifically,
The voltage application time in the pretreatment step can be equal to or longer than the voltage application time in the determination step. As a result, the defect reserve army can be efficiently and reliably grown into a true defect.

Moreover, in order to solve the above-mentioned problem, the wiring defect inspection apparatus according to the present invention
A voltage application unit for applying a voltage to the wiring provided on the semiconductor substrate;
A control unit for controlling the voltage application unit;
An infrared camera that detects infrared rays from a semiconductor substrate that has generated heat by voltage application under the control of the control unit;
With
The control unit controls the voltage application unit so that a voltage is applied to the wiring before the infrared camera is detected by the infrared camera, and a voltage non-application state is maintained for a predetermined time after the application. It is characterized by that.

  According to said structure, the short circuit preliminary | backup part which is a front | former stage of a wiring short circuit part which becomes a wiring short circuit part if a voltage is applied can be made to grow into a wiring short circuit part by applying a voltage. For this reason, when only infrared detection is performed without applying the voltage, the wiring including the short-circuit spare portion does not generate heat so that it is determined that there is a wiring short-circuit portion, and erroneously states that there is no wiring short-circuit portion. Thus, it is possible to avoid a situation that appears as a wiring short-circuit portion due to voltage application in a subsequent process. That is, according to the wiring defect inspection method according to the present invention, since the determination step is performed after the short-circuit spare portion is grown into the wiring short-circuit portion, there is an effect that accurate determination can be performed.

  Moreover, according to said structure, after applying a voltage and making a short circuit preliminary part grow into a wiring short circuit part, a voltage non-application state is maintained for a predetermined time. As a result, the short-circuit path including the wiring short-circuit portion grown from the short-circuit spare portion, which has been heated by the voltage application, cools, and at the start of the inspection by the infrared camera, the original wiring short-circuit portion and the short-circuit spare portion grow. The temperature can be unified with the wiring short-circuit portion. Therefore, the temperature rise by voltage application in the wiring short-circuit portion originally present and the wiring short-circuit portion grown from the short-circuit spare portion can be started under the same conditions. Therefore, accurate determination can be performed.

In addition to the above configuration, one aspect of the wiring defect inspection apparatus according to the present invention is
It further includes a data capturing unit that captures a resistance value measured in advance of the wiring,
The control unit is configured to control the voltage value of the applied voltage for the heat generation based on the resistance value captured by the data capturing unit when the infrared camera detects the infrared light. Is preferred.

  According to the above configuration, by applying a voltage specified based on the resistance value of the wiring measured in advance to the semiconductor substrate (leak defect substrate), the amount of heat generated in the semiconductor substrate (leak defect substrate) is constant. Thus, the temperature increase can be reliably confirmed by the infrared inspection using the infrared camera, and the short circuit portion can be specified. Further, since the applied voltage is not too high to burn out the defective portion, the short-circuit portion can be identified stably.

  In addition, since resistance measurement is performed in a separate device, resistance measurement and infrared camera imaging can be operated in parallel, and the processing capability can be improved.

Moreover, instead of the above configuration, one form of the wiring defect inspection apparatus according to the present invention,
It further comprises a resistance measurement unit for measuring the resistance value of the wiring,
The control unit is configured to control the voltage value of the applied voltage for the heat generation based on the resistance value measured by the resistance measurement unit when detecting the infrared ray by the infrared camera. It is preferable.

  According to the above configuration, by applying a voltage specified based on a resistance value acquired in advance by a resistance test to the semiconductor substrate, the amount of heat generated in the semiconductor substrate becomes constant, and infrared rays using an infrared camera are used. The temperature rise can be surely confirmed by the inspection, and the short circuit portion can be specified. Further, since the applied voltage is not too high to burn out the defective portion, the short-circuit portion can be identified stably.

  Furthermore, since the wiring defect inspection device itself measures the resistance value of the wiring, it is not necessary to separately provide a device for measuring the resistance value, so that the number of devices can be reduced.

  As described above, the wiring defect inspection method and the wiring defect inspection apparatus according to the present invention can detect the short circuit spare part without missing it, and can accurately identify the short circuit part.

1 is a block diagram illustrating a configuration of a wiring defect inspection apparatus according to an embodiment of the present invention, and a perspective view illustrating a configuration of a mother substrate having a liquid crystal panel. It is a perspective view which shows the structure of the said wiring defect inspection apparatus. It is a top view of the liquid crystal panel and probe used in embodiment of this invention. It is a flowchart which shows the wiring defect inspection method which concerns on embodiment of this invention. It is a schematic diagram which shows the defect of the pixel part used in embodiment of this invention. It is a graph explaining the defect detection of a comparative example. It is a schematic diagram which shows the short circuit path | route used in embodiment of this invention.

Embodiment 1
An embodiment of a wiring defect inspection method and a wiring defect inspection apparatus according to the present invention will be described with reference to FIGS.

(Configuration of wiring defect inspection equipment)
1A is a block diagram illustrating a configuration of a wiring defect inspection apparatus 100 that performs the wiring defect inspection method according to the present embodiment, and FIG. 1B illustrates a wiring defect using the wiring defect inspection apparatus 100. It is a perspective view of the mother board | substrate 1 (semiconductor substrate) which is a test object.

  The wiring defect inspection apparatus 100 can inspect wiring defects (short circuit defects) of a plurality of liquid crystal panels 2 (semiconductor substrates) formed on the mother substrate 1 shown in FIG. Therefore, the wiring defect inspection apparatus 100 includes a probe 3 for conducting with the liquid crystal panel 2 and a probe moving unit 4 for moving the probe 3 onto each liquid crystal panel 2. The wiring defect inspection apparatus 100 also includes an infrared camera 5 for acquiring an infrared image, and camera moving means 6 for moving the infrared camera 5 on the liquid crystal panel 2. The wiring defect inspection apparatus 100 further includes a control unit 7 that controls the probe moving unit 4 and the camera moving unit 6.

  The probe 3 is connected to a voltage application unit 9 for applying a voltage between the wirings of the liquid crystal panel 2. The voltage application unit 9 is controlled by the control unit 7. Although the details will be described later, the voltage application unit 9 uses the control unit 7 to measure the heat generation and to apply a voltage to the probe 3 in the determination step for specifying the position of the short-circuited portion, and at a stage prior to the determination step. A voltage is applied to the probe 3 in a certain pretreatment step.

  The probe 3 is connected to a resistance measuring unit 8 for measuring the resistance between the wires of the liquid crystal panel 2. The resistance measuring unit 8 is also controlled by the control unit 7.

  The control unit 7 is connected to a data storage unit 10 that stores resistance values between wirings and image data.

  FIG. 2 is a perspective view showing a detailed configuration of the wiring defect inspection apparatus 100 according to the present embodiment. As shown in FIG. 2, the wiring defect inspection apparatus 100 is configured such that an alignment stage 11 is installed on a base, and the mother substrate 1 can be placed on the alignment stage 11. The alignment stage 11 on which the mother substrate 1 is placed is adjusted in parallel with the XY coordinate axes of the probe moving unit 4 and the camera moving unit 6. At this time, for the position adjustment of the alignment stage 11, an optical camera 12 provided above the alignment stage 11 for confirming the position of the mother substrate 1 is used.

  The probe moving means 4 is slidably installed on a guide rail 13 a disposed outside the alignment stage 11. Guide rails 13b and 13c are also installed on the main body side of the probe moving means 4, and the mount portion 14a is installed so as to be able to move in the XYZ coordinate directions along these guide rails 13. A probe 3 corresponding to the liquid crystal panel 2 is mounted on the mount portion 14a.

  The camera moving means 6 is slidably installed on a guide rail 13d disposed outside the probe moving means 4. Further, guide rails 13e and 13f are also installed on the main body of the camera moving means 6, and the three mount portions 14b, 14c, and 14d are separately moved along the guide rails 13 in the XYZ coordinate directions. can do.

  An infrared camera 5a for macro measurement is mounted on the mount portion 14c, an infrared camera 5b for micro measurement is mounted on the mount portion 14b, and an optical camera 16 is mounted on the mount portion 14d.

  The infrared camera 5a for macro measurement is an infrared camera capable of macro measurement with a field of view expanded to about 520 × 405 mm. The infrared camera 5a for macro measurement is configured by combining, for example, four infrared cameras in order to widen the field of view. That is, the field of view per macro measurement infrared camera is approximately ¼ that of the mother board 1.

  The infrared camera 5b for micro measurement is an infrared camera capable of micro measurement capable of shooting with high resolution although the field of view is as small as about 32 × 24 mm.

  The camera moving means 6 may be equipped with a laser irradiation device for correcting a defective portion by adding a mount portion. By mounting the laser irradiation device, the defect can be continuously corrected by irradiating the defect with a laser after specifying the position of the defect.

  The probe moving means 4 and the camera moving means 6 are installed on separate guide rails 13a and 13d, respectively. Therefore, it is possible to move above the alignment stage 11 in the X coordinate direction without interfering with each other. As a result, the infrared cameras 5 a and 5 b and the optical camera 16 can be moved onto the liquid crystal panel 2 while the probe 3 is in contact with the liquid crystal panel 2.

  FIG. 3A is a plan view of one liquid crystal panel 2 among the plurality of liquid crystal panels 2 formed on the mother substrate 1. As shown in FIG. 3A, each liquid crystal panel 2 includes a pixel portion 17 in which a TFT is formed at each intersection where the scanning line and the signal line intersect, and a driving circuit that drives the scanning line and the signal line, respectively. A portion 18 is formed. Terminal portions 19 a to 19 d are installed at the edge of the liquid crystal panel 2, and the terminal portions 19 a to 19 d are connected to the wiring of the pixel portion 17 or the drive circuit portion 18.

  FIG. 3B is a plan view of the probe 3 for conducting with the terminal portions 19 a to 19 d installed on the liquid crystal panel 2. The probe 3 has a frame-like shape that is almost the same size as the liquid crystal panel 2 shown in FIG. 3A, and a plurality of probes corresponding to the terminal portions 19 a to 19 d installed on the liquid crystal panel 2. Needles 21a to 21d are provided.

  The probe needles 21a to 21d are individually connected to the resistance measuring unit 8 and the voltage applying unit 9 shown in FIG. 1A through switching relays (not shown). Can do. For this reason, the probe 3 can selectively connect a plurality of wires connected to the terminal portions 19a to 19d, or can connect the plurality of wires together.

  The probe 3 has a frame shape that is substantially the same size as the liquid crystal panel 2. Therefore, when the positions of the terminal portions 19 a to 19 d and the probe needles 21 a to 21 d are aligned, the positions can be confirmed using the optical camera 16 from the inside of the frame of the probe 3.

  As described above, the wiring defect inspection apparatus 100 according to the present embodiment includes the probe 3 and the resistance measurement unit 8 connected to the probe 3. The probe 3 is electrically connected to the liquid crystal panel 2, and each of them is connected. The resistance value of the wiring and the resistance value between adjacent wirings can be measured. The wiring defect inspection apparatus 100 according to this embodiment includes a probe 3, a voltage application unit 9 connected to the probe 3, and infrared cameras 5 a and 5 b. It is possible to determine the position of the defective part by measuring the heat generated by applying a voltage to the defective part and using the infrared cameras 5a and 5b. Therefore, according to the wiring defect inspection apparatus 100 of this embodiment, a single inspection apparatus can be used for both resistance inspection and infrared inspection. Furthermore, in the present embodiment, as described above, the voltage is applied to the probe 3 in the pretreatment process that is a stage before the determination process for measuring the heat generation and specifying the position of the short-circuited portion, thereby wiring the liquid crystal panel 2. A pretreatment process is performed in which a short-circuit spare part, which is a short-circuit reserve army that has not yet reached a short-circuit, is short-circuited to make a wiring short-circuit. That is, it can be realized in one wiring defect inspection apparatus 100 including a pretreatment process before resistance inspection and infrared inspection.

(Wiring defect inspection method)
FIG. 4 is a flowchart of a wiring defect inspection method performed using the wiring defect inspection apparatus 100 described above. In the wiring defect inspection method according to this embodiment, as shown in FIG. 4, the wiring defect inspection is sequentially performed on the plurality of liquid crystal panels 2 formed on the mother substrate 1 by the steps S <b> 1 to S <b> 10. .

  In step S1, the mother substrate 1 is placed on the alignment stage 11 of the wiring defect inspection apparatus 100, and the position of the substrate is adjusted to be parallel to the XY coordinate axes.

  In step S2, the probe moving means 4 moves the probe 3 to the upper part of the liquid crystal panel 2 to be inspected, and the probe needles 21a to 21d come into contact with the terminal portions 19a to 19d of the liquid crystal panel 2.

  In step S3, corresponding to various defect modes, wirings for subsequent resistance inspection or between the wirings are selected, and the probe needle 21 to be conducted is switched.

  In step S4 (pretreatment step), a voltage is applied to the probe needle 21 switched in step S3. The applied voltage value has a strength equal to or higher than the voltage value applied in the subsequent heat generation step. A longer voltage application time is stronger, and a higher applied voltage is stronger. As an example, a voltage of 60 V and 3 seconds is applied. By applying this voltage, the short-circuit spare part, which is a short-circuit reserve army that does not reach the wiring short-circuit in the liquid crystal panel 2, is short-circuited to form a wiring short-circuit (defective part 23). When the short-circuit spare part grows into the defect part 23, the wiring including the defect part 23 generates heat. In addition, the voltage application method in step S4 may be applied continuously or may be intermittently applied a plurality of times. Further, the voltage may be gradually increased from the start of voltage application.

  Further, in step S4, the voltage non-application state is maintained for a predetermined time after the voltage application as described above. By providing this voltage non-application time, the short circuit spare part becomes the wiring short circuit part (defect part 23) by the voltage application and the heat generated between the wirings or wirings is cooled. There is no particular limitation on the maintenance time in the non-application state. In addition, it is not necessary to cool completely, for example, if there is a non-application state even for an extremely short time of about 0.3 seconds, it may be cooled even slightly during that time.

  In step S5 (resistance value measurement step), a resistance test is performed. In step S5, the resistance value between the selected wirings or wirings is measured, and the presence / absence of a defect is inspected by comparing the resistance value with the resistance value when there is no defect. As a specific example, a resistance test threshold value stored in advance in the data storage unit 10 is compared. Here, when the resistance value acquired in step S5 is larger than the resistance inspection threshold value stored in advance in the data storage unit 10, it can be specified that the liquid crystal panel 2 under inspection has no defect, which will be described later. The process proceeds to step S9. On the other hand, when the resistance value acquired in step S5 is equal to or less than the resistance inspection threshold value stored in advance in the data storage unit 10, it can be specified that there is a defect between the wirings in the liquid crystal panel 2 being inspected. Then, the process proceeds to step S7.

  When the inspection result shows that there is a defect, the measured resistance value is stored in the data storage unit 10.

  Here, in FIGS. 5A to 5C, as an example, the position of the defective portion 23 (wiring short-circuit portion) generated in the pixel portion 17 is schematically shown.

  FIG. 5A shows, for example, in a liquid crystal panel in which the wiring X and the wiring Y intersect vertically like the scanning line and the signal line, the defective portion 23 in which the wiring X and the wiring Y are short-circuited at the intersection. Is shown. The probe needle 21 to be conducted is switched to the pair of 21a and 21d or the pair of 21b and 21c shown in FIG. 3, and the resistance value between the wirings is measured 1: 1 with respect to the wirings X1 to X10 and the wirings Y1 to Y10. Thus, the presence and position of the defective portion 23 can be specified.

  FIG. 5B shows a defective portion 23 that is short-circuited between adjacent wiring lines X such as a scanning line and an auxiliary capacitance line. Such a defective portion 23 is obtained by switching the probe needle 21 to be conducted to a pair of the odd number 21b and the even number 21d and measuring the resistance value between the adjacent wires X1 to X10. The wiring with the part 23 can be specified. When the inspection result shows that there is a defect, the measured resistance value is stored in the data storage unit 10.

  FIG. 5C shows a defective portion 23 that is short-circuited between adjacent wirings Y such as a signal line and an auxiliary capacitance line. Such a defective portion 23 is obtained by switching the probe needle 21 to be electrically connected to a pair of the odd number 21a and the even number 21c and measuring the resistance value between the adjacent wires Y1 to Y10. The wiring with the part 23 can be specified. When the inspection result shows that there is a defect, the measured resistance value is stored in the data storage unit 10.

  In step S6, it is determined whether or not to perform infrared inspection based on the presence or absence of the defective portion 23 inspected in step S5. If there is a defect 23, the process proceeds to step S7 to perform infrared inspection, and if there is no defect 23, the process proceeds to step S9 without performing infrared inspection. It can be said that this step S6 is a part of the resistance value measuring step.

  For example, as shown in FIG. 5A, when a defect 23 occurs at a location where the wiring X and the wiring Y intersect, an abnormality is detected in the wiring X4 and the wiring Y4 by the resistance inspection between the wirings. The position up to the defect portion 23 can be specified. Therefore, in the case of the defect portion 23 shown in FIG. 5A, it is not always necessary to specify the position by infrared inspection (step S6). That is, if the resistance inspection is performed for every combination of the wiring X and the wiring Y, the position can be specified, so that the infrared inspection is unnecessary. However, since the number of combinations is enormous, it takes a long time. For example, in the case of a full high-definition liquid crystal panel, since there are 1080 wirings X and 1920 wirings Y, there are approximately 2.70 million combinations. If resistance inspection is performed for each such combination, the tact time becomes long, and the inspection processing capability is greatly reduced, which is not realistic. Therefore, the number of resistance inspections can be reduced by combining all the combinations of the wiring X and the wiring Y into several and performing a resistance inspection. For example, if a resistance inspection is performed between the wiring X grouped together and the wiring Y grouped together, the number of times of the resistance inspection is only one. However, a short circuit between wirings can be detected by resistance inspection, but the position cannot be specified. Therefore, it is necessary to specify the position of the defective portion 23 by infrared inspection.

  On the other hand, as shown in FIG. 5 (b) or FIG. 5 (c), when a defective portion 23 occurs between adjacent wirings, there is a defective portion between a pair of wirings, for example, the wiring X3 and the wiring X4. Can be identified. However, since the position of the defect portion 23 cannot be specified in the length direction of the wiring, it is necessary to specify the position of the defect portion 23 by infrared inspection.

  Since the resistance inspection between adjacent wirings is enormous, it takes a long time. For example, in the case of a full high-definition liquid crystal panel, the number of resistance inspections between adjacent wires X is 1079 times, and the number of resistance inspections between adjacent wires Y is 1919 times. In the case of resistance inspection between adjacent wirings X as in the case of FIG. 5B, if resistance inspection is performed between all X odd numbers and all X even numbers, the number of resistance inspections is only one. Times. In the case of resistance inspection between adjacent wirings Y as in FIG. 5C, if resistance inspection is performed between all Y odd numbers and all Y even numbers, the number of resistance inspections is only one. Times. However, a short circuit between wirings can be detected by resistance inspection, but the position cannot be specified. Therefore, it is necessary to specify the position of the defective portion 23 by infrared inspection.

  In step S7 (determination step, heat generation step), an infrared inspection is performed on the liquid crystal panel 2 that is determined to require an infrared inspection. In step S 7, a voltage value is set based on the resistance value stored in the data storage unit 10 in step S 5, and the voltage of the voltage value is applied to the liquid crystal panel 2 by the voltage application unit 9. Specifically, in this embodiment, an applied voltage V (volt) proportional to the square root of the resistance value acquired in step S5 is applied to the liquid crystal panel 2. That is, in step S7, the applied voltage V (volt) is changed to the following formula (1);

And set.

  Here, the calorific value J (joule) per unit time is expressed by the following formula (2):

From the above formulas (1) and (2), the calorific value J per unit time is represented by the following formula (3);

It is expressed.

  That is, by applying an applied voltage V (volt) proportional to the square root of the resistance value to the liquid crystal panel 2 based on the formula (1), the heat generation amount per unit time can be made constant.

  Therefore, although the resistance value of the short circuit path including the defect 23 varies greatly depending on the type of the substrate or the cause of the short circuit such as the location of the defect 23 on the substrate, the unit time can be increased by performing step S5 of the present embodiment. The amount of heat generated per hit can be made constant.

  Thus, according to step S7, the presence / absence of a defect is determined by resistance inspection. When it is determined that there is a defect, the resistance value in the short-circuit path of the liquid crystal panel 2 is acquired and specified based on the resistance value. A voltage is applied to the liquid crystal panel 2. Thereby, since either the defect part 23 or the wiring part generates heat sufficiently, the position of the defect can be easily recognized during the infrared inspection. Further, there is no possibility that the position of the defect portion 23 is not known because the heat generation amount of the defect portion 23 and the wiring portion is insufficient. Furthermore, since the high voltage is not applied too much and the defective portion 23 is not burned out, the position of the defective portion 23 can be identified stably during the infrared inspection.

  The voltage adjustment in step S7 is performed by the control unit 7 shown in FIG.

  In step S8 (determination step, position specifying step), in order to detect infrared light from the defect portion 23 that has generated heat due to the application of the voltage, the defect portion 23 is photographed using an infrared camera. To do. In this embodiment, the infrared camera 5a for macro measurement and the infrared camera 5b for micro measurement are provided. First, using the infrared camera 5a for macro measurement that can fit the wide range of the liquid crystal panel 2 in the field of view, If necessary, the position of the defect 23 is specified by scanning the infrared camera 5a for macro measurement. Subsequently, if necessary, the periphery of the heat generating part may be measured using the infrared camera 5b for micro measurement. Since the position of the heat generating portion is specified by the infrared camera 5a for macro measurement, the camera can be moved so that the heat generating portion is located within the field of view of the infrared camera 5b for micro measurement, and the defective portion 23 coordinate positions can be specified with high accuracy, or information such as a shape necessary for correction can be measured. In the present embodiment, the infrared camera 5a for macro measurement and the infrared camera 5b for micro measurement are provided for shooting in two stages, but the present invention is not limited to this, A configuration may be used in which shooting is performed in one stage using one infrared camera. Or you may implement the imaging | photography step like the modification mentioned later.

Here, the short circuit path, which is configured from the wiring portion and the defect portion 23, the heating value J of short-circuit path is configured with the heating value J ₁ of the wiring part, from the calorific value J ₂ Metropolitan defect portion 23 Is done.

And as follows:
(A) when the resistance of the defect portion 23 is relatively small, the heat generation amount J ₂ of the defect portion 23 becomes smaller. However, since the heating value J of short-circuit path as discussed above it is constant, the amount of heat generation J ₂ of the defect portion 23 is reduced, the calorific value J ₁ of the wiring portion is increased. Therefore, it is possible to easily recognize a wiring portion that generates heat in the infrared image. Then, by further analyzing the recognized portion and specifying a portion where the wiring and the wiring are short-circuited, the defective portion 23 can be detected.

(B) when the resistance of the defect portion 23 is relatively large, the heating value J ₂ of the defect portion 23 increases. In this case, since the calorific value J of short-circuit path as discussed above it is constant, the amount of heat generation J ₂ of the defect portion 23 increases, calorific value J ₁ of the wiring portion is reduced. Therefore, it is possible to easily recognize the defective portion 23 that generates heat well in the infrared image.

  (C) When the resistance value of the defect portion 23 is neither small nor large, as described above, since the heat generation amount J of the short-circuit path is constant, both the defect portion 23 and the wiring portion generate heat to the same extent. . Therefore, the defect portion 23 and the wiring portion can be easily recognized from the infrared image.

  According to the above (a) to (c), either the defective portion 23 or the wiring portion generates sufficient heat. Therefore, in the photographed infrared image, the temperature of the defective portion 23 or the wiring portion through which the current flows is higher than the surroundings. Is displayed. Thereby, the position of the defect part 23 is specified easily. The specified position is stored in the data storage unit 10.

  In step S9, it is determined whether or not all inspections in various defect modes have been completed for the liquid crystal panel 2 being inspected. If there is an uninspected defect mode, the process returns to step S3. Then, the connection of the probe 3 is switched in accordance with the next defect mode, and the defect inspection is repeated. Here, the defect mode is a type of the defect portion 23 as shown in FIG. FIG. 5 shows three defect modes. That is, the short-circuit defect mode between the wiring X and the wiring Y in FIG. 5A, the short-circuit defect mode between the wiring X in FIG. 5B, and the short-circuit defect mode between the wiring Y in FIG.

  In step S10, it is determined whether or not the defect inspection of all the liquid crystal panels 2 has been completed for the mother substrate 1 being inspected. If the uninspected liquid crystal panel 2 remains, the process returns to step S2. Then, the probe is moved to the liquid crystal panel 2 to be inspected next, and the defect inspection is repeated.

(Operational effect of this embodiment)
According to this embodiment, even if it is a short circuit spare part which is a 'short circuit reserve army' in a stage before a wiring short circuit that cannot be said to be a defective part 23 in a state where no voltage is applied, it is detected using an infrared camera. Can do.

  Here, the effect of this embodiment is demonstrated, pointing out the problem of a comparative example. FIG. 6 is a graph showing the relationship between the voltage application time and the temperature rise value of the wiring arranged in the liquid crystal panel when the above-described heat generation process is performed in the liquid crystal panel of the comparative example. In FIG. 6, a portion where the temperature rises (heat generation) by 1 ° C. or more when a voltage is applied for 2 seconds is detected as a defective portion. That is, the defect A in FIG. 6 can be detected. Here, the defect A is a so-called true defect in which the wiring is short-circuited before the voltage application is started. Here, FIG. 6 shows an increase in temperature of the defect B, but the defect B is a defect reserve army (short-circuit reserve part) that has not yet been short-circuited before the start of voltage application. This defect B is a defect that grows into a wiring short circuit (true defect) 1.5 seconds after the start of voltage application. Then, the defect B grows into a true defect 1.5 seconds after the start of voltage application, and gradually generates heat from 1.5 seconds onward. However, the defect B does not reach the threshold temperature increase of 1 ° C. even after 2 seconds from the start of voltage application. That is, in the comparative example, the position of the defect B is not specified as a defect even in the position specifying process. If the defect B is overlooked in this way, it adversely affects the liquid crystal panel or the liquid crystal display device equipped with the liquid crystal panel in a subsequent process. Therefore, in the present embodiment, a voltage is applied at a stage before the heat generation process and the position specifying process, and the defect B is grown as a true defect. Similarly, it can be in a state where it has already become a true defect. For this reason, in the heat generation process and the position specifying process, the position is characterized, and the repairing process as described above can be performed. That is, according to the wiring defect inspection method of the present embodiment, there is an effect that accurate determination can be performed.

  Moreover, according to said structure, after applying a voltage and making a short circuit preliminary part grow into a wiring short circuit part in a pre-processing process, a voltage non-application state is maintained for a predetermined time. As a result, in the pretreatment process, the short circuit path (the short circuit path including the wiring short circuit part grown from the short circuit preparatory part) that has risen in temperature due to voltage application is cooled, and the wiring short circuit that originally existed at the start of the inspection by the infrared camera The temperature can be unified between the portion and the wiring short-circuit portion grown from the short-circuit spare portion. Therefore, the temperature rise by voltage application in the wiring short-circuit portion originally present and the wiring short-circuit portion grown from the short-circuit spare portion can be started under the same conditions. Therefore, a more accurate determination can be performed.

  As described above, according to the present embodiment, it is possible to avoid the inspection failure by a simple method of applying a voltage without considering the direction of the current between the wirings of the liquid crystal panel or between the wirings.

(Modification)
In the present embodiment, as shown in FIG. 1, the configuration provided with the resistance measurement unit 8 that measures the resistance value of the wiring has been described. However, the present invention is not limited to this, and the wiring is measured in advance. As a configuration including a data capturing unit (not shown) that captures the resistance value, the control unit 7 controls the voltage value of the applied voltage for the heat generation based on the resistance value captured by the data capturing unit. It may be configured.

  With this configuration, since resistance measurement is performed in a separate device, resistance measurement and infrared camera imaging can be operated in parallel, and the processing capability can be improved.

[Embodiment 2]
Another embodiment according to the present invention will be described. In the present embodiment, a device similar to the device in the first embodiment is used. In the first embodiment described above, in step S7, the applied voltage V (volt) proportional to the square root of the resistance value acquired in step S5 is applied to the liquid crystal panel 2. On the other hand, in this embodiment, the applied voltage V (volt) proportional to the resistance value acquired in step S5 is applied to the liquid crystal panel 2 ((b) and FIG. 2 in FIG. 1).

  Specifically, in step S6 of the present embodiment, the applied voltage V (volt) is changed to the following formula (4);

And set. Here, the current I (ampere) is expressed by the following formula (5);

It becomes. That is, the current can be made constant by appropriately determining the applied voltage.

  Here, the resistance value R of the wiring formed on the substrate is expressed by the following equation (6):

The electrical resistivity ρ and the cross-sectional area A are constants determined by the type and location of the wiring. Therefore, the resistance value R / L = ρ / A of the wiring per unit length is also a constant. That is, if the number assigned to each wiring type and location is i, the resistance value r (i) per unit length of the wiring i is expressed by the following equation (7):

It is expressed.

  Therefore, the calorific value of the wiring i per unit length of the wiring i is expressed by the following formula (8) from the above formulas (2), (5) and (7):

It becomes.

  Here, FIG. 7 is a diagram for explaining the short-circuit path, and is an example of an electrical wiring diagram of the thin film transistor substrate. In the thin film transistor substrate of FIG. 7, scanning lines (wirings) 31 to 35 and signal lines (wirings) 41 to 45 are arranged in a grid pattern on a glass substrate, and thin film transistors and transparent pixel electrodes (not shown) are connected to each intersection. This is a substrate on which 5 × 5 pixels are formed as a whole. A thin film transistor substrate and a common electrode substrate (not shown) are arranged in parallel and a liquid crystal is sealed between them, which is a liquid crystal panel. In addition, as shown in FIG. 7, the leading end portions of the lead lines 31p to 35p of the scanning lines are commonly connected to the thin film transistor substrate by the common line 30 to prevent electrostatic breakdown. The same applies to the signal lines. In the thin film transistor substrate shown in FIG. 7, a short-circuit portion 50 is formed between the scanning line 33 and the signal line 43. In such a thin film transistor substrate, considering the case where the short-circuit path is divided as lead line 33p → scan line 33 → short-circuit point 50 → signal line 43 → lead line 43p, the scan line 33 and signal per unit length are considered. The heat generation amount of the line 43 can be made constant.

  Accordingly, the scanning line 33 and the signal line 43 can be stably recognized from the infrared image by appropriately determining the constant m in advance regardless of the magnitude of the electrical resistance of the short-circuited portion.

  Then, by further analyzing the recognized wiring portion and specifying a portion where the scanning line 33 and the signal line 43 are short-circuited, the short-circuited portion can be specified. If the resistance value at the short-circuited portion is high, the amount of heat generated at the short-circuited portion increases, and therefore the short-circuited portion can be easily identified from the infrared image.

  Further, in order to determine the voltage based on the resistance value of the wiring, the control unit 7 may execute the process of calculating the above formula (1) or formula (4) each time. Alternatively, the relationship between the resistance value and the voltage may be stored in advance as a table, and the control unit 7 may refer to this table each time and determine the voltage from the resistance value.

  As described above, also by the wiring defect inspection method and the wiring defect inspection apparatus of the present embodiment, defects can be recognized from an infrared image as in the first embodiment.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is not limited to said embodiment. Various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention.

  The present invention can be used for inspection of a wiring state of a semiconductor substrate having wiring such as a liquid crystal panel.

1 Mother board (semiconductor board)
2 Liquid crystal panel (semiconductor substrate)
DESCRIPTION OF SYMBOLS 3 Probe 4 Probe moving means 5a, 5b Infrared camera 6 Camera moving means 7 Control part (control part)
8 Resistance measurement unit 9 Voltage application unit 10 Data storage unit 11 Alignment stages 12, 16 Optical cameras 13a, 13b, 13c, 13d, 13e, 13f Guide rails 14a, 14b, 14d, 14d Mount unit 17 Pixel unit 18 Drive circuit unit 19a , 19b, 19c, 19d Terminal portions 21a, 21b, 21c, 21d Probe portion 23 Defective portion (wiring short-circuit portion)
30, 40a, 40b Common lines 31, 32, 33, 34, 35 Scan lines 31p, 32p, 33p, 34p, 35p Scan line leader lines 41, 42, 43, 44, 45 Signal lines 41p, 42p, 43p, 44p, 45p Signal line lead line 50 Short circuit point 100 Wiring defect inspection device

Claims (7)

A voltage is applied to the wiring provided on the semiconductor substrate to generate heat in the short-circuit path including the wiring short-circuit portion. Including a determination step for identifying
Prior to the determination step,
A wiring defect inspection method comprising a pretreatment step of applying a voltage to the wiring and maintaining a voltage non-application state for a predetermined time after the application. Between the pretreatment step and the determination step, by measuring the resistance value of the wiring, including a resistance value measurement step of determining the presence or absence of a wiring short-circuit portion,
The determination process is as follows:
A voltage specified based on the resistance value measured in the resistance value measurement step is applied to a short-circuit path including the wiring short-circuit portion of the semiconductor substrate determined to have the wiring short-circuit portion in the resistance value measurement step. A heating step for generating heat in the short circuit path;
Shooting the short-circuit path that has generated heat in the heat generation step with an infrared camera, and specifying the position of the wiring short-circuit portion based on the information of the shooting,
The wiring defect inspection method according to claim 1, further comprising:   The wiring defect inspection method according to claim 1, wherein the voltage applied in the pretreatment step is equal to or higher than the voltage applied in the determination step.   4. The wiring defect inspection method according to claim 1, wherein the voltage application time in the pretreatment step is equal to or longer than the voltage application time in the determination step. 5. A voltage application unit for applying a voltage to the wiring provided on the semiconductor substrate;
A control unit for controlling the voltage application unit;
An infrared camera that detects infrared rays from a semiconductor substrate that has generated heat by voltage application under the control of the control unit;
With
The control unit controls the voltage application unit so that a voltage is applied to the wiring before the infrared camera is detected by the infrared camera, and a voltage non-application state is maintained for a predetermined time after the application. A wiring defect inspection apparatus characterized by the above. It further includes a data capturing unit that captures a resistance value measured in advance of the wiring,
The control unit is configured to control the voltage value of the applied voltage for the heat generation based on the resistance value captured by the data capturing unit when the infrared camera detects the infrared light. The wiring defect inspection apparatus according to claim 5. It further comprises a resistance measurement unit for measuring the resistance value of the wiring,
The control unit is configured to control the voltage value of the applied voltage for the heat generation based on the resistance value measured by the resistance measurement unit when detecting the infrared ray by the infrared camera. The wiring defect inspection apparatus according to claim 5.

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