JP2006300665A - Inspection device, and conductive pattern inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection device and an inspection method, which detect an open circuit/short circuit of a conductive pattern. <P>SOLUTION: A tip part of a probe 30 is brought into contact with one end in either one out of the conductive patterns 15a, 15b arrayed regularly, a sensor part 20 having a size astride over a wiring pattern thereof and the adjacent pattern is positioned in a position with a prescribed separate distance from the patterns, and the probe 30 and the sensor part 20 are moved on an inspection objective substrate while synchronized. The short circuit or the like is judged, for example, on the basis of a difference between a detection signal in a usual time and a detection signal in an abnormal time, and a tendency in a level change between the detection signals. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to, for example, an inspection apparatus and a conductive pattern inspection method capable of inspecting the quality of a conductive pattern formed on a glass substrate.

  As a method for inspecting a conductive pattern (conductor pattern) formed on a circuit board, a pin is brought into contact with both ends of a conductor pattern to be inspected, an inspection signal is supplied from one end side thereof, and an inspection signal is supplied from the other end side. A contact method is known in which an inspection signal is received to perform a continuity test on the conductor pattern. In this method (also called a pin contact method, the details of which are described in, for example, Patent Document 1), if an inspection signal is detected at the power receiving end, it is assumed that conduction is ensured and the pattern to be inspected is normal. If the inspection signal is not detected, the conductor pattern is determined to be in a disconnected state.

  In addition to confirming that the inspection signal supplied to the conductor pattern to be inspected normally passed through the conductor pattern, an inspection probe is also placed in the pattern adjacent to the conductor pattern to be inspected, and inspection is performed from the adjacent pattern. There is also a method of determining a short-circuit state between a conductor pattern to be inspected and an adjacent pattern based on whether or not a signal is detected.

JP-A-62-269075

  However, in the inspection by the above-described pin contact method, for example, a metallic pin probe is erected on all the terminals of the substrate to be inspected, and an electric signal is sent to the conductive pattern via these probes. Therefore, although there is an advantage that a good S / N ratio (signal-to-noise ratio) can be obtained for the inspection signal, there is a problem that it is not possible to cope with the inspection of a highly dense conductor pattern in recent times.

  For example, when a high-definition pattern with a wiring pitch width of 50 μm or less is inspected, the manufacturing cost of a probe card composed of a narrow-pitch multiple probe is high. In addition, providing an open detection sensor for inspecting a disconnection state and a short sensor for inspecting a short-circuit state (short-circuit state) between adjacent patterns separately means that the configuration of the inspection result analysis program and the inspection apparatus Not only is it complicated, but there is a limit to downsizing the sensor unit itself, so efficient inspection cannot be performed.

  On the other hand, in a liquid crystal display panel incorporating a TFT (thin film transistor), a short circuit (also referred to as an interlayer short circuit or a cross short circuit) between a data line pattern and a gate line pattern is conventionally inspected based on pattern image processing. It was. However, there has been a problem that it is difficult to reliably and rapidly detect such an interlayer short in terms of resolution, processing speed, and the like.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an inspection apparatus and a conductive pattern inspection method that can detect an open state / short state of a conductive pattern with high accuracy.

  Another object of the present invention is to provide an inspection device and a conductive pattern inspection method capable of detecting an open state / short state of a conductive pattern on a TFT substrate with a simple device configuration.

  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 an inspection apparatus for inspecting the state of a conductive pattern arranged on a substrate, and includes a signal supply means for supplying an inspection signal to one end of the conductive pattern to be inspected, and the inspection target. A signal detection unit having a size covering at least the conductive pattern and a conductive pattern adjacent to the conductive pattern at the other end of the conductive pattern, and the signal supply unit and the signal detection unit to sequentially scan the conductive pattern Scanning means for positioning and moving, and identification means for identifying the quality of the conductive pattern based on a change in the signal detected by the signal detection means, wherein the signal supply means is at least an arrangement pitch width of the conductive pattern A signal supply terminal having a width equal to or less than that of the conductive pattern, and sequentially tracing one end of the conductive pattern with the signal supply terminal. The signal detection means moves in the scanning direction in synchronization with the signal supply means, and detects the inspection signal in a non-contact manner through capacitive coupling with the conductive pattern. It is characterized by that.

  For example, when the signal detection means sequentially shows two signals out of the inspection signals sequentially detected from the conductive pattern to be inspected by the signal detection means that are higher than the signal level in a normal state. It is determined that the conductive pattern is short-circuited with an adjacent pattern.

  In addition, for example, when the signal detection unit does not detect the inspection signal from the conductive pattern to be inspected, the identification unit determines that the conductive pattern is disconnected.

  For example, when the conductive pattern is arranged on two different wiring layers, if the level of the inspection signal detected by the signal detection means is lower than the signal level in a normal state, the identification means It is determined that the conductive pattern of the wiring layer is short-circuited with the conductive pattern of the other wiring layer.

  For example, when the conductive pattern is arranged in two different wiring layers, the signal level of the inspection signal detected sequentially from the conductive pattern to be inspected by the signal detection means is a signal level in a normal state. If it is higher, the identification means determines that the conductive pattern is disconnected in a region other than the region sandwiched between the signal detection means and the signal supply means.

  Further, for example, the identifying means identifies the disconnection of the conductive pattern to be inspected and the short-circuit between the conductive patterns based on the result of comparing the signal level of the detected inspection signal and a predetermined threshold value. Features.

  For example, for each of the detected inspection signals, the identification unit obtains a level change tendency of the entire inspection signal from a level difference from the preceding and subsequent signals, and the level change of the inspection signal detected from the conductive pattern to be inspected is detected. If the level change tendency does not coincide, it is determined that the conductive pattern is disconnected or short-circuited with an adjacent pattern.

  As another means for solving the above-described problem, for example, the following configuration is provided. That is, the present invention is a conductive pattern inspection method in an inspection apparatus for inspecting the state of a conductive pattern arranged on a substrate, and at least a signal supply terminal having a width equal to or less than the arrangement pitch width of the conductive pattern. A step of supplying an inspection signal to one end portion of the conductive pattern to be inspected from a signal supply means having, and at least the conductive pattern and the conductivity adjacent to the conductive pattern at the other end portion of the conductive pattern to be inspected A step of detecting the inspection signal in a non-contact manner through capacitive coupling with the conductive pattern by a signal detecting means having a size covering the pattern; and the signal supply terminal sequentially detects one end of the conductive pattern. The signal detection means sequentially scans the other end of the conductive pattern in synchronization with the signal supply means. And a step of positioning and moving the signal supply means and the signal detection means, and a step of identifying the state of the conductive pattern based on a change in the signal detected in the signal detection step. .

  For example, in the identification step, when two signals among the inspection signals sequentially detected from the conductive pattern to be inspected by the signal detection unit continuously show a level higher than a signal level in a normal state. Determining that the conductive pattern is short-circuited with an adjacent pattern, and determining that the conductive pattern is disconnected when the signal detection means does not detect the inspection signal from the conductive pattern to be inspected; It is characterized by.

  For example, in the identification step, when the conductive pattern is arranged on two different wiring layers, if the level of the inspection signal detected by the signal detection means is lower than the signal level in a normal state, the conductive pattern It is determined that the pattern is short-circuited with the conductive pattern of another layer.

  In addition, for example, the identifying step may include a single signal level among the inspection signals sequentially detected from the conductive pattern to be inspected by the signal detection means when the conductive pattern is arranged on two different wiring layers. When the signal level is higher than the signal level in the normal state, it is determined that the conductive pattern is disconnected in a region other than the region sandwiched between the signal detection unit and the signal supply unit.

  For example, the identifying step identifies a disconnection of a conductive pattern to be inspected and a short-circuit between conductive patterns based on a result of comparing a signal level of the detected inspection signal with a predetermined threshold value. To do.

  Further, for example, in the identification step, for each of the detected inspection signals, a level change tendency of the entire inspection signal is obtained from a level difference from the preceding and succeeding signals, and the level of the inspection signal detected from the conductive pattern to be inspected When the change does not coincide with the level change tendency, it is determined that the conductive pattern is disconnected or short-circuited with an adjacent pattern.

  According to the present invention, it is possible to accurately and easily detect a short circuit state of a conductive pattern on a substrate to be inspected.

  Further, according to the present invention, it is possible to reliably detect short-circuits of conductor patterns having various specifications, including interlayer short-circuits on the TFT substrate, with simple and simple control.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited to the relative arrangement | positioning of a component demonstrated below, a numerical value, etc. at all, and unless there is specific description, the scope of the present invention is not the meaning which limits the following description.

  FIG. 1 is a diagram for explaining the principle of a conductive pattern inspection method in the substrate inspection apparatus according to the present embodiment. An inspection target substrate 10 of the substrate inspection apparatus shown in FIG. 1 is, for example, a liquid crystal display panel or a touch panel. Here, the quality of the row-shaped conductive patterns 15 regularly arranged on a glass substrate ( The disconnection state of the conductive pattern and the short-circuit state between the wiring patterns) are inspected. Each row-like conductive pattern 15 is, for example, a wiring pattern before pasting in these panels and has substantially the same pattern shape, and as its conductive material, for example, chromium, silver, aluminum, ITO, etc. Is used.

  The probe 30 is an inspection signal supply terminal having a diameter sufficiently smaller than the pitch of the row conductive patterns 15. The tip of the probe 30 has flexibility, for example, and is configured to contact only one of the conductive patterns. And the inspection signal is supplied to the conductive pattern by the tip part contacting the row-shaped conductive pattern 15. Here, in order to sequentially supply inspection signals to the pattern to be inspected, the probe 30 is scanned from one end of the substrate 10 to the other end in the direction of the arrow in the figure. Meanwhile, the inspection signal continues to be supplied from the supply unit (AC signal generation unit) 35 to the probe 30.

  The sensor unit 20 is positioned at a position separated from the column-shaped conductive pattern 15 of the liquid crystal display panel by a predetermined distance, and is scanned in the arrow direction in the drawing in synchronization with the probe 30. The sensor unit 20 is, for example, a rectangular electrode plate having a size that covers two wiring patterns (covers at least two wiring patterns). At the time of inspection, an inspection signal is supplied from the probe 30 to any one of the two wiring patterns straddled by the sensor unit 20. Therefore, the inspection signal supplied to the columnar conductive pattern 15 reaches the sensor unit 20 through capacitive coupling (electrostatic coupling) between the conductive patterns and the sensor unit 20.

  In the scanning described above, the sensor unit 20 and the probe 30 are moved in synchronization with each other, or the positions of the sensor unit 20 and the probe 30 are fixed with respect to the substrate (liquid crystal display panel) 10. A stage (not shown) on which the substrate 10 is placed (for example, one capable of three-dimensional position control by four-axis control of XYZθ angles) is moved on the order of μm so as to move relatively in the direction of the arrow 1. It may be. In any case, the position control and scanning control of the sensor unit 20 and the probe 30 are performed so that the inspection signal is always supplied from the probe 30 to one of the two wiring patterns that the sensor unit 20 straddles.

  Since the signal detected by the sensor unit 20 is a minute signal, it is sent to the amplifier 25 in order to amplify it with a predetermined amplification degree. The amplifier 25 is composed of, for example, an operational amplifier (op-amp) having an input impedance Z. The signal amplified by the amplification unit 25 is input to the display device 26 that displays the detection result. Here, the amplifier 25 is disposed immediately after the sensor unit 20 to eliminate the influence of external noise and the like on the detection signal.

  With the above configuration, an AC inspection signal is supplied from the AC power source 35 to the inspection signal supply terminal (probe) 30, the columnar conductive pattern 15 supplied with the inspection signal is used as one electrode, and the sensor unit 20 is used as the other electrode. The detection signal from the sensor unit 20 is amplified by the amplifier 25, and the obtained inspection signal is examined. As a result, the open state of the conductive patterns 15 arranged in a row on the substrate 10 can be individually inspected.

  That is, when an inspection signal is supplied to the conductive pattern to be inspected among the row-shaped conductive patterns 15, the capacitance formed by the conductor having the width of the conductive pattern and the facing portion (electrode plate) of the sensor unit 20 is reduced. Thus, an inspection signal which is an alternating current is supplied to the amplifier 25 side. For this reason, an AC voltage having a predetermined amplitude is output from the output terminal of the amplifier 25. Therefore, this output voltage is determined mainly by the area of the facing portion of the sensor unit 20 and the distance (gap) between the conductor and the sensor unit.

  For example, when the adjacent conductive patterns are all arranged at the same pitch, such as a liquid crystal panel, the capacitance formed by the conductive pattern and the opposing portion of the conductive pattern of the sensor unit 20 is substantially the same. It becomes. As a result, when there is no short circuit or the like in the pattern, detection signals of substantially the same level are obtained for each conductive pattern as will be described later.

  On the other hand, if there is a short circuit in the conductive pattern, an inspection signal is supplied to both the conductive pattern to be inspected and the shorted conductive pattern. Therefore, the output waveform of the amplifier 25 is monitored to determine whether the conductive pattern is short-circuited. By doing in this way, even if it does not perform the special positioning of a probe, etc., a defective part can be detected reliably with a simple configuration, and a defective part can be specified.

  In addition, the conductive pattern to be inspected is not limited to the above-described columnar conductive pattern, for example, even if the conductive pattern is a comb-like conductive pattern in which one end of the conductive pattern is opened and the base is short-circuited by a short bar, By sequentially scanning them, the quality of the pattern can be determined based on the same principle as described above.

  FIG. 2 is a specific configuration example of an inspection apparatus that realizes the inspection method described above. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals. In FIG. 2, the liquid crystal panel 10 to be inspected is positioned at the inspection position, and the sensor unit 20 is disposed at one end of the inspection target conductive pattern on the liquid crystal panel 10 in a non-contact state with the conductive pattern to be inspected. In addition, the probe 30 is positioned at the other end of the conductive pattern so that the tip thereof is in contact with the conductive pattern.

  The sensor unit 20 has a metal electrode (for example, an aluminum (Al) electrode) disposed on at least a surface thereof, and has a larger capacitance with respect to the conductive pattern than, for example, a semiconductor is used as an electrode. It is comprised so that it may become. The signal detected by the sensor unit 20 is sent to the analog signal processing circuit 50. The signal subjected to the analog signal processing by the analog signal processing circuit 50 is sent to the control unit 60, and the quality of the wiring pattern is determined. Note that the control unit 60 also performs control to supply the inspection signal to the inspection signal supply terminal 30 as described later.

  The analog signal processing circuit 50 amplifies the detection signal from the sensor unit 20, removes the noise component of the detection signal amplified by the amplifier 51, and passes only the inspection signal, and its bandpass A rectifier circuit 53 that full-wave rectifies the signal from the filter 52 and a smoothing circuit 54 that smoothes the detection signal that has been full-wave rectified by the rectifier circuit 53 are provided.

  The control unit 60 controls the entire inspection apparatus including overall control such as an inspection sequence to be described later. For example, a central processing unit (CPU) 61 composed of a microprocessor, a control procedure for the CPU 61, a substrate inspection procedure, and the like are performed by a computer. ROM 62 stored as a program, RAM 63 used as a work area for temporarily storing processing information (control data, inspection data) and the like of the CPU 61, A for converting an analog signal from the analog signal processing circuit 50 into a corresponding digital signal / D converter 64, a signal supply unit 65 for supplying an inspection signal to the inspection signal supply terminal 30, and a display unit 66 made of, for example, a CRT or a liquid crystal display for visual display of inspection results and operation instruction guidance. .

  The signal supply unit 65 generates, for example, a sine wave signal having a signal level of 10 Vp-p and 100 KHz as the inspection signal, and supplies it to the inspection signal supply terminal 30. In this case, the bandpass filter 52 has a band for allowing a 100 KHz signal to pass therethrough.

  The inspection signal supply terminal (probe) 30 moves while tracing the signal supply terminal portion (connection terminal) etc. of the conductive pattern whose tip is the inspection target, and sequentially inspects each conductive pattern. Supply the signal. The tip of the probe 30 is formed of, for example, a flexible tungsten alloy, and has a size that is less than the pattern pitch of the pattern to be inspected (the pattern width of the conductive pattern and the pattern gap). For example, by setting the wire diameter of the base portion to 150 μm and the tip portion (tracing portion) diameter to 15 μm, it is possible to inspect a conductive pattern on a substrate having a pattern width to be inspected of 30 μm and a pattern gap of about 20 μm. it can.

  The robot controller 70 controls the scalar robot 80 under the control of the control unit 60. The scalar robot 80 positions and holds the liquid crystal panel 10 at the inspection position, and holds the tip portion of the inspection signal supply terminal 30 in contact with all the connection terminals of the liquid crystal panel 10 according to the control of the robot controller 70. The tip portion is scanned so as to sequentially trace all the connection terminals.

  Next, an inspection method in the substrate inspection apparatus according to the present embodiment will be described. FIG. 3 is a flowchart showing the inspection procedure of the present embodiment. First, in step S1 in FIG. 3, the liquid crystal panel 10 to be inspected is transported and set to a predetermined position (inspection position) of the substrate inspection apparatus along a transport path (not shown). Subsequently, in step S2, a flag (NG flag) indicating that there is a defective portion in the inspection target pattern is reset, and "1" is set in the N flag indicating the inspection target conductive pattern, so that the quality of the first conductive pattern is acceptable. Make a decision. As a result, the preparation for starting the inspection is completed. In the subsequent step S3, the control unit 60 waits for a start instruction input indicating the start of the inspection.

  If there is a start instruction, the process proceeds to step S4, where an instruction is given to the robot controller 70 to control the scalar robot 80, and the inspection signal supply terminal (probe) 30 is moved to the inspection start position of the conductive pattern to be inspected. In step S5, the signal supply unit 65 is activated, an inspection signal is output to the inspection signal supply terminal (probe) 30, the tip portion is brought into contact with the inspection target conductive pattern, and the signal supply unit is supplied to the predetermined conductive pattern. The inspection signal from 65 is transmitted and supplied.

  At the same time, the analog signal processing circuit 50 is activated and reading of the inspection signal from the sensor unit 20 is started. Thereafter, until the “tracing” by the inspection signal supply terminal 30 is completed, the detection data for every predetermined time is sequentially taken and stored in the RAM 63, for example. When the scanning of the conductive pattern to be inspected by the inspection signal supply terminal 30 is completed, the process proceeds to step S7, and the signal supply unit 65 is deactivated. After that, the process proceeds to a conductive pattern pass / fail judgment process described later.

  FIG. 4 is a flowchart showing the pass / fail judgment processing procedure of the conductive pattern in the substrate inspection apparatus according to the present embodiment. For example, when the substrate inspection apparatus is inspecting the nth conductive pattern, the detection voltage value of the sensor unit 20 when the inspection signal is supplied to the conductive pattern (nth) in step S11 of FIG. read out. If it is the first pattern (first), the detection voltage value by the sensor unit 20 when the inspection signal supply terminal 30 supplies the inspection signal to the conductive pattern at the position where the tracing is started is read out.

  Subsequently, in step S12, whether or not the detection voltage (output voltage) at the sensor unit 20 is equal to or higher than a predetermined threshold value based on the detection level when the pattern is in a normal state, and adjacent to other than the inspection target wiring pattern. It is checked whether or not a signal is detected from the pattern. If it is below the specified threshold and no signal is detected from the adjacent pattern, it is determined that the wiring pattern is normal and the process proceeds to step S13.

  On the other hand, in step S12, when the value of the signal detected by the sensor unit 20 is equal to or greater than the specified threshold value and a signal is detected from an adjacent pattern other than the inspection target wiring pattern, the process proceeds to step S15, and the nth wiring pattern Is determined to be short-circuited with the wiring pattern adjacent thereto. In step S16, “1” is set in the NG flag, and the process proceeds to step S17. That is, if a short circuit is detected during the inspection, the inspection time can be further shortened by stopping the further “tracing control” and immediately proceeding to the next process assuming that the target substrate is defective.

  In step S13, the value of the N flag is checked to determine whether or not it indicates the last wiring pattern of the wiring pattern to be inspected. If the pass / fail judgment has not been completed for all the wiring patterns to be inspected on one liquid crystal panel 10, the process proceeds to step S14, and the N flag is incremented by 1 to specify the wiring pattern to be inspected next. (N = n + 1). Then, the process returns to step S11. The determination as to whether or not the inspection has been completed for all the wiring patterns to be inspected is, for example, the movement distance of the sensor unit 20 or the inspection target substrate (liquid crystal panel 10) is the sum of all the wiring pattern widths and those patterns. This is performed based on whether or not the distance obtained by adding up the total of the intervals matches.

  On the other hand, if it is determined in step S13 that the quality determination of the wiring pattern to be inspected has been completed to the end, the process proceeds to step S17. In step S17, the inspection result is displayed. For example, the NG flag is checked, and when the NG flag is set, the display unit 66 displays that the liquid crystal panel 10 is a defective panel in which the wiring pattern is short-circuited (NG display). . When the NG flag is not set, a display (OK display) indicating that the liquid crystal panel 10 is normal is performed.

  In step S18, the liquid crystal panel is removed from the substrate inspection apparatus (the liquid crystal panel is lowered to the transport position and placed on the transport path and transported to the next stage, or the defective panel is removed from the transport path). Do). In subsequent step S19, it is checked whether or not the inspection of the liquid crystal panel is completed. If there is a liquid crystal panel to be inspected next, the process returns to step S1 shown in FIG. 3 to set a new liquid crystal panel. However, when there is no panel to be inspected next, the inspection is terminated in step S19, and this processing is terminated.

  In the above example, every time an inspection result is obtained, control is performed so as to determine whether the pattern is in a short circuit state or the like. However, the present invention is not limited to this. For example, a single inspection substrate (liquid crystal After the inspection results from all the inspection target patterns on the panel) are collected, the quality of the substrate may be determined by collectively performing data processing or the like.

  In addition, the setting of the liquid crystal panel to be inspected and the removal thereof are not limited to the above example. For example, the liquid crystal panel is automatically set and removed, and the removed liquid crystal panel is judged as good or bad. Accordingly, the product may be automatically stored in the non-defective product storage unit or the defective product storage unit. Further, the above inspection process may be incorporated into a part of the production line, the liquid crystal panel sent from the upstream side may be inspected, and only good products may be conveyed downstream.

  Next, the inspection result in the substrate inspection apparatus according to the present embodiment will be specifically described. FIG. 5 shows an example of the inspection result when the inspection target is a columnar conductive pattern in the substrate inspection apparatus according to the present embodiment. As shown in FIG. 5, the probe 30 moves in the direction of the arrow while supplying an AC inspection signal to each of the conductive patterns 15 a, 15 b, and the sensor unit 20 moves in the same direction in synchronization with the probe 30. An inspection signal is detected in a non-contact manner from the conductive pattern 15 of the liquid crystal panel to be inspected. When the conductive pattern to be inspected is a normal pattern without a short circuit or the like like the conductive patterns 15a and 15b in FIG. 5, when an inspection signal is sequentially supplied to these conductive patterns 15a and 15b, each conductive pattern Since there is a capacitor (capacitor) that is equivalently connected between the sensor unit 20 and the stage (not shown), the sensor unit 20 can obtain the detection signals SG1 and SG2 of almost the same level from any pattern.

  On the other hand, when there is a short circuit 90 between the patterns as in the conductive patterns 15c and 15d, the inspection signal is applied not only to the conductive pattern 15c to which the probe 30 supplies an AC inspection signal but also to the conductive pattern 15d that is short-circuited to the conductive pattern 15c. Flows in. As a result, detection signals SG3 and SG4 are obtained from both of the conductive patterns 15c and 15d. Further, when there is a short circuit between the conductive patterns, a difference occurs in the intensity of the detection signal as compared with the case where there is no short circuit, and the voltage level sensed by the sensor 20 also changes.

  That is, as shown in FIG. 5, a signal having a level higher than that obtained from other normal conductive patterns is detected from the short-circuited conductive patterns 15c and 15d. In addition, when there is a short circuit between the patterns, two high-level signals (SG3, SG4) are detected in time series. In this way, the high level signal is detected when a part of the conductive pattern is short-circuited, the area of the conductive pattern facing the sensor unit 20 is almost double that of one conductive pattern when the pattern is normal. This is because the output of the amplifier 25 increases significantly compared to the case where there is no short circuit because the area is equal to two.

  On the other hand, when there is an open portion 91 in a part thereof as in the conductive pattern 15f of FIG. 5, even if the probe 30 is in contact with the conductive pattern 15f and an inspection signal is supplied, the sensor 20 No signal is detected from. Therefore, no detection signal appears at the output terminal of the amplifier 25.

  Next, another example of the inspection result in the substrate inspection apparatus according to the present embodiment will be described. FIG. 6 shows an example of a pattern inspection result when a liquid crystal display panel or the like (hereinafter simply referred to as a TFT substrate) having a wiring layer having a two-layer structure incorporating TFTs (thin film transistors) is used as an inspection target. In this TFT substrate, a first wiring layer and a second wiring layer are formed in a laminated state in an upper layer / lower layer positional relationship, and the first wiring layer is a TFT transistor ( The conductive pattern 15 as a data line (not shown) is formed on the lower glass substrate, and the second wiring layer is formed on the upper glass substrate so that the conductive pattern 17 as the gate line is orthogonal to the conductive pattern 15. Become. The conductive pattern 15 has a configuration in which one end is opened and a base is short-circuited by a short bar 19 via a tab (TAB) region 18.

  Also in the TFT substrate having the two-layer conductive pattern shown in FIG. 6, in the inspection of the conductive pattern, the probe 30 is moved in the direction of the arrow to supply the AC inspection signal to each of the conductive patterns 15a, 15b. 20 is moved in the same direction in synchronization with the probe 30. The sensor unit 20 detects the inspection signal in a non-contact manner from the conductive pattern 15. When there is no short circuit or the like in the conductive pattern, detection signals of substantially the same level are obtained from those patterns, such as SG1, SG4, SG6, and SG7.

  When there is a short-circuited portion 94 between the conductive patterns 15b and 15c, the inspection signal flows into the conductive pattern 15b and the conductive pattern 15c that is short-circuited therewith, so that detection signals SG2 and SG3 are obtained from both of the conductive patterns. At this time, as in the case shown in FIG. 5, the signal intensity is different from the signal level when there is no short circuit, and two signals (SG2, SG3) having a level higher than the normal level are detected in succession. Is done.

On the other hand, when there is a short circuit (also referred to as an interlayer short circuit or cross short circuit) 95 between the conductive pattern 15e of the first wiring layer and the conductive pattern 17d of the second wiring layer, as shown by x in FIG. The inspection alternating current i supplied to the conductive pattern 15e from 30 is shunted at the short-circuited portion 95 and flows to the conductive pattern 17d of the second wiring layer as currents i ′ and i ″. In addition, since the capacitors (capacitors) C ₁ and C ₂ are equivalently connected to a stage (not shown), the signal current from the probe 30 serving as a power feeding section is transmitted through these conductive patterns. This is because it flows into the capacity.

  Thus, when there is an interlayer short on the TFT substrate, the inspection signal current is diverted from the conductive pattern of one layer to the conductive pattern of the other layer at the short-circuited portion. Therefore, in FIG. 6, the signal level detected by the sensor unit 20 positioned on the conductive pattern 15e is lower than the normal level when there is no short circuit, as in the detection signal SG5 in FIG. Therefore, it is possible to easily determine whether or not there is a short circuit between layers only by detecting this level.

  On the other hand, in the tab (TAB) region 18, when there is an open portion 96 in a part of the conductive pattern 15h, even if an inspection signal is supplied from the probe 30 to one end of the conductive pattern 15h, most of the inspection current is obtained. Then, it flows to the sensor 20 side through capacitive coupling with the conductive pattern. This is because if there is an open portion in the tab area, the ground (GND) is removed. Therefore, in this case, the signal level detected by the sensor 20 is higher than the normal level as the signal SG8 in FIG.

  In the inspections shown in FIG. 5 and FIG. 6, if a constant threshold is set for the output of the amplifier 25 and the level of the detection signal is equal to or higher than the threshold, the position of the probe 30 at that time is used. Therefore, it is determined that the conductive pattern has a short-circuit portion with another pattern. This is because there is a large difference between the level of the detection waveform in the conductive pattern that is short-circuited and the level of the detection waveform in the normal state.For example, the average detection level in the normal state is half of the difference between the detection signal in the normal state and the short-circuit state Even if the value obtained by adding the values of (1/2) is set as the threshold value of whether or not a short circuit occurs, a short circuit can be detected.

However, as described above, in the substrate inspection apparatus according to the present embodiment, the sensor unit is disposed in a non-contact state with the conductive pattern to be inspected. The voltage level detected by the sensor unit varies depending on the inspection object (liquid crystal display panel or the like). For example, when fluctuation occurs with respect to the entire level of the measured voltage as shown by a dotted line in FIG. 7B, a constant threshold A _th is set in the output voltage waveform of the amplifier as shown in FIG. 7A. However, it is difficult to accurately identify a normal conductive pattern and a pattern such as a short circuit based only on the level of the measured voltage.

Therefore, as shown in FIG. 7B, for each signal waveform, the level difference from the signal waveform before and after it is obtained, and the change tendency of the entire output voltage waveform is obtained from the increasing or decreasing tendency of the level difference. For example, in FIG. 7B, for each signal waveform, level differences ΔA _{1 to} ΔA ₈ from the signal waveforms before and after the signal waveform are obtained. And the change tendency which those level differences show is judged as the change tendency of the whole output voltage waveform shown by the dotted line of Drawing 7 (b).

In the example shown in FIG. 7B, the level difference ΔA ₃ between the signal SGa and the signal SGb and the level difference ΔA ₄ between the signal SGb and the signal SGc are greatly different from the level difference (change tendency) between the other signals. . Therefore, it can be determined that the change tendency of the level difference between the signals does not match the overall change tendency indicated by the dotted line for the signal SGb. Therefore, in this case, it can be determined that the signal SGb is a signal corresponding to a certain conductive pattern such as a short circuit.

  FIG. 7C shows an example in which the change tendency of the entire output voltage waveform is different from that in FIG. 7B, that is, a case where the change tendency is gentle as shown by a dotted line. Even in this case, for each signal waveform, determine the level difference from the signal waveform before and after it, and check whether the change trend matches the change trend of the entire output voltage waveform indicated by the dotted line. The presence or absence of a certain conductive pattern is determined.

  As described above, the method of detecting the presence or absence of a short circuit of the conductive pattern by performing a relative comparison based on the change tendency of the level difference of the detection signal of the adjacent pattern, the detection data from each conductive pattern is stored in the RAM or the like. The inspection method is stored in order, and after all the conductive patterns have been scanned, it conforms to the inspection method for collectively performing the pass / fail judgment process for the conductive patterns.

  As described above, according to the present embodiment, the probe tip is brought into contact with only one of the regularly arranged conductive patterns, and the conductive pattern and a pattern adjacent thereto. The sensor unit having a size over the two is positioned in a non-contact state at a position separated from the pattern by a predetermined distance, and the probe and the sensor unit are synchronized to move on the inspection target substrate. By doing so, it is not necessary to position each of the conductive patterns to be inspected and bring the inspection pins into contact with each other, and it is possible to detect a short circuit or an open state of the conductive pattern simply by tracing and scanning the inspection target pattern. Therefore, the inspection apparatus can be simplified and a reliable and highly reliable pattern inspection can be realized.

  In addition, even if the pitch of the conductive pattern to be inspected is different, the conductive pattern is surely short-circuited by simply scanning so that the tracing position of the inspection probe crosses the inspection target pattern without performing special control. Can be detected. In addition, the difference between the normal detection signal level and the detection target level at the time of abnormality, which are subject to detection, not only clearly appears, but especially when there is a short circuit, a high-level signal in the signal arranged in time series Since two are detected in succession, a reliable and highly reliable test result can be obtained.

  Furthermore, among the inspection target patterns, for example, it is only necessary to sequentially scan the connection terminal portions, so even if the pattern placement status of the inspection target pattern is changed, the accurate positioning of the inspection pins is unnecessary, By simply controlling the scanning route, it is possible to perform a short circuit inspection of a conductive pattern without any complicated positioning control even if the wiring is complicated or the pattern interval of the pattern to be inspected varies.

  In addition, even when a TFT substrate having a two-layer wiring layer is an object to be inspected, if there is an interlayer short between the conductive pattern of the first wiring layer and the conductive pattern of the second wiring layer, detection from the pattern Since the signal level is lower than the normal level without a short circuit, it is possible to easily determine whether or not there is a short circuit between the layers simply by detecting the level.

It is a figure for demonstrating the principle of the inspection method of the conductive pattern in the board | substrate inspection apparatus which concerns on the embodiment of this invention. It is a block diagram which shows the specific structure of the board | substrate inspection apparatus which concerns on the example of embodiment. It is a flowchart which shows the test | inspection procedure in the board | substrate inspection apparatus which concerns on the example of embodiment. It is a flowchart which shows the quality determination process sequence of the conductive pattern in the board | substrate inspection apparatus which concerns on the embodiment. It is a figure which shows an example of the test result in the board | substrate inspection apparatus which concerns on the embodiment. It is a figure which shows an example of the test result of the TFT substrate in the board | substrate inspection apparatus which concerns on the example of an embodiment. It is a figure for demonstrating the level determination method of the detection signal in the board | substrate inspection apparatus which concerns on the example of an embodiment.

Explanation of symbols

10 Substrate (liquid crystal display panel)
15a, 15b conductive pattern 18 tab (TAB) region 20 sensor unit 25, 51 amplifier 26 display device 30 probe 35 AC signal generating unit 50 analog signal processing circuit 60 control unit 90, 94, 95 short-circuited part 91 open part

Claims (15)

An inspection device for inspecting the state of a conductive pattern arranged on a substrate,
Signal supply means for supplying an inspection signal to one end of the conductive pattern to be inspected;
A signal detecting means having a size covering at least the conductive pattern and a conductive pattern adjacent to the conductive pattern at the other end of the conductive pattern to be inspected;
Scanning means for positioning and moving the signal supply means and the signal detection means so as to sequentially scan the conductive pattern;
An identification means for identifying the quality of the conductive pattern based on a change in the signal detected by the signal detection means,
The signal supply means has at least a signal supply terminal having a width equal to or less than the arrangement pitch width of the conductive pattern, and moves in the scanning direction while sequentially tracing one end of the conductive pattern at the signal supply terminal. The signal detection means moves in the scanning direction in synchronization with the signal supply means, and detects the inspection signal in a non-contact manner through capacitive coupling with the conductive pattern. apparatus. The identification unit is configured to perform the conduction when two signals among the inspection signals sequentially detected from the conductive pattern to be inspected by the signal detection unit continuously show a level higher than a signal level in a normal state. The inspection apparatus according to claim 1, wherein the pattern is determined to be short-circuited with an adjacent pattern. The inspection apparatus according to claim 1, wherein the identification unit determines that the conductive pattern is disconnected when the signal detection unit does not detect the inspection signal from the conductive pattern to be inspected. When the conductive pattern is arranged on two different wiring layers, if the level of the inspection signal detected by the signal detection means is lower than the signal level in a normal state, the identification means The inspection apparatus according to claim 1, wherein the conductive pattern is judged to be short-circuited with the conductive pattern of the other wiring layer. When the conductive pattern is arranged on two different wiring layers, the single signal level of the inspection signals sequentially detected from the conductive pattern to be inspected by the signal detection unit is higher than the signal level in a normal state. 2. The inspection apparatus according to claim 1, wherein when the height is high, the identification unit determines that the conductive pattern is disconnected in a region other than the region sandwiched between the signal detection unit and the signal supply unit. . The identification means identifies disconnection of a conductive pattern to be inspected and short-circuit between conductive patterns based on a result of comparing a signal level of the detected inspection signal with a predetermined threshold value. Item 6. The inspection device according to any one of Items 1 to 5. For each of the detected inspection signals, the identification unit obtains a level change tendency of the entire inspection signal from a level difference from the preceding and succeeding signals, and the level change of the inspection signal detected from the conductive pattern to be inspected is the level. 6. The inspection apparatus according to claim 1, wherein if the change tendency does not coincide with the change tendency, it is determined that the conductive pattern is disconnected or short-circuited with an adjacent pattern. A conductive pattern inspection method in an inspection apparatus for inspecting the state of a conductive pattern arranged on a substrate,
Supplying an inspection signal to one end of the conductive pattern to be inspected from a signal supply means having a signal supply terminal having a width equal to or less than the arrangement pitch width of the conductive pattern;
At the other end portion of the conductive pattern to be inspected, the signal detecting means having a size covering at least the conductive pattern and the conductive pattern adjacent to the conductive pattern is not coupled via capacitive coupling with the conductive pattern. Detecting the inspection signal by contact;
The signal supply terminal and the signal are sequentially traced at one end of the conductive pattern, and the signal detection means sequentially scans the other end of the conductive pattern in synchronization with the signal supply means. Positioning and moving the detection means;
And a step of identifying the state of the conductive pattern based on a change in the signal detected in the signal detecting step. In the identification step, when the signal detection means sequentially detects two of the inspection signals sequentially detected from the conductive pattern to be inspected and shows a level higher than the signal level in a normal state, It is determined that a pattern is short-circuited with an adjacent pattern, and when the signal detection unit does not detect the inspection signal from the conductive pattern to be inspected, it is determined that the conductive pattern is disconnected. The conductive pattern inspection method according to claim 8. In the identification step, when the conductive pattern is arranged on two different wiring layers, and the level of the inspection signal detected by the signal detection means is lower than the signal level in a normal state, the conductive pattern is The conductive pattern inspection method according to claim 9, wherein the conductive pattern is determined to be short-circuited with a conductive pattern of another layer. In the identification step, when the conductive pattern is arranged on two different wiring layers, the single signal level among the inspection signals sequentially detected from the conductive pattern to be inspected by the signal detection unit is normal. 10. The conductive pattern according to claim 9, wherein the conductive pattern is determined to be disconnected in a region other than the region sandwiched between the signal detection unit and the signal supply unit. Inspection method. The identifying step identifies a disconnection of a conductive pattern to be inspected and a short-circuit between conductive patterns based on a result of comparing a signal level of the detected inspection signal with a predetermined threshold value. Item 12. The conductive pattern inspection method according to any one of Items 8 to 11. In the identification step, for each of the detected inspection signals, a level change tendency of the entire inspection signal is obtained from a level difference from the preceding and succeeding signals, and the level change of the inspection signal detected from the conductive pattern to be inspected is the level. 12. The conductive pattern inspection method according to claim 8, wherein if the change tendency does not coincide, it is determined that the conductive pattern is disconnected or short-circuited with an adjacent pattern. A computer-readable recording medium storing a computer program for realizing the conductive pattern inspection method according to claim 8 by computer control. A computer program sequence for realizing the conductive pattern inspection method according to claim 8 by computer control.

Images