JP4817014B2 - Temperature measuring method in substrate inspection apparatus and substrate inspection apparatus - Google Patents

Description

The present invention relates to a substrate inspection in which a substrate is inspected for defects by detecting secondary electrons obtained by irradiating the substrate with an electron beam, and the heating temperature of the substrate heated in a vacuum heating apparatus provided in the substrate inspection apparatus is determined. The present invention relates to a temperature measurement method and a substrate inspection apparatus .

  For example, Patent Documents 1 and 2 are known as inspection apparatuses for inspecting the state (defectiveness) of a pixel on a TFT array substrate such as a flat panel display using an electron beam.

  This inspection device is a device that identifies a defect point from measurement image data, acquires image data (two-dimensional data) corresponding to the pixel array of the TFT substrate to be inspected from the measurement signal value, and detects the defect from this image data. By extracting pixels, inspection information such as defect coordinates and defect type classification is acquired.

  Here, in order to extract a defective pixel from image data, it is performed by extracting a pixel having a specific signal intensity, and the extracted pixel is used as a defective pixel. In addition, in the defect type classification, defects that are large and exist as isolated points (point defects), or defects that are lines due to a set of points that are continuous in the horizontal or vertical direction (line defects) being classified. Each point defect or line defect is further classified as a grouped defect according to the presence or absence of a mutual correlation.

  In the inspection apparatus, the correlation output corresponding to the state (good or bad) of each pixel of the TFT array substrate to be inspected can be measured as the signal intensity of each pixel, and the two-dimensional image data is constituted by the measurement signal intensity. can do.

  For example, the defect type is classified by extracting a point having an intensity value below this threshold as a defect point in the measured image data (two-dimensional data) as a threshold value (Threshold). The set of defect points is further grouped and classified. In this way, a set of defect points extracted from the measured two-dimensional (image) data is grouped and classified according to their positional or shape features and output as final inspection information.

  In substrate inspection, it has been proposed to detect defects that are difficult to detect at low temperatures by heating the substrate to be inspected and performing inspection at high temperatures. As means for heating the substrate, a configuration in which a heater is provided in the stage and a configuration in which a heating lamp is provided are known. In such substrate heating, it is required to know the heating temperature of the substrate. Conventionally, the temperature measurement of a heated substrate is not a direct measurement by bringing the temperature sensor into contact with the substrate, because it may interfere with the substrate inspection or damage the substrate itself. Indirect measurement is performed in which the temperature in the atmosphere in the chamber in which the substrate is placed is measured.

  Although it is not a technique for inspecting a substrate for defects as in the present invention, as a non-contact temperature measurement technique, a mounting component mounted on a substrate is imaged by an infrared sensor, and the mounting component is obtained from the obtained image data. A technique for measuring the temperature of these is proposed (see Patent Document 3).

JP-A-11-265678 JP 2000-3142 A JP 2005-114553 A

  As described above, when performing a defect inspection of a substrate in a heated state, the conventional method only measures the temperature of the substrate by indirect measurement such as measuring the temperature in the heat generating part or the atmosphere, so high measurement accuracy Further, there is a problem that the temperature distribution of the entire substrate cannot be obtained because only the temperature in the vicinity of a part of the substrate is estimated. In particular, in the case of a large substrate, a number of temperature sensors are required to measure the temperature with a temperature sensor for measuring the temperature in the heat generating part or the atmosphere as in the past. However, since the vacuum chamber is usually a limited space from the viewpoint of evacuation, the number of places where the temperature sensor can be installed is limited, and the number of temperature sensors necessary for obtaining the temperature distribution of the entire substrate is arranged. It is difficult.

  In addition, in order to apply the measurement technology that measures the temperature of mounted parts from image data using the infrared sensor described above, there is a problem that it is necessary to newly install an infrared sensor, and furthermore, the temperature of a large substrate is measured. In order to achieve this, it is necessary to dispose the infrared sensor at a position where the entire substrate can be seen, but it is difficult to find a desired position of the infrared sensor in a vacuum chamber in a limited space.

  SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems and to measure the temperature of a heated substrate in a vacuum heating apparatus and to measure the temperature distribution of the substrate.

  Moreover, it aims at measuring the temperature distribution of a board | substrate, without requiring the additional apparatus for temperature measurement.

  This light utilizes the fact that there is a correlation between the intensity and temperature of secondary electrons emitted from a substrate when the substrate is irradiated with an electron beam. The temperature of the substrate is obtained from the detected secondary electron intensity. Since the temperature measurement point corresponds to the irradiation position of the electron beam, the temperature distribution of the substrate can be measured by scanning the irradiation position of the electron beam on the substrate regardless of the arrangement configuration in the vacuum chamber.

  Moreover, in a substrate inspection apparatus that performs defect inspection of a substrate by detecting secondary electrons obtained by irradiating the substrate with an electron beam, the function of the substrate inspection apparatus can be used as it is, so that temperature measurement Therefore, it is not necessary to add a new device.

The present invention can be the embodiment of the temperature measuring method in a substrate inspection device, the embodiment of the substrate inspection device.

An aspect of a temperature measurement method in the substrate inspection apparatus of the present invention is a temperature measurement method for measuring the temperature of a substrate in a vacuum heating device of a substrate inspection device including a vacuum chamber and a heating device, and the substrate disposed in the vacuum chamber Based on the step of obtaining the intensity of the secondary electrons emitted from the substrate by the irradiation of the electron beam to the substrate and the correlation between the obtained secondary electron intensity and the temperature, Determining the temperature.

  Further, the method includes a step of obtaining an irradiation position of the electron beam on the substrate, and obtaining a temperature distribution of the substrate from the measurement position and the temperature, using the irradiation position of the electron beam as a temperature measurement position.

  The irradiation position of the electron beam on the substrate can be obtained from the position of the stage that supports the substrate and the scanning control that determines the deflection of the electron beam.

Further, an aspect of the substrate inspection apparatus according to the present invention is a vacuum heating apparatus including a vacuum chamber and a heating apparatus, a secondary electron detector that detects secondary electrons obtained from the substrate by irradiation with an electron beam, and the secondary electron detector. And a temperature measuring unit that measures the temperature of the substrate disposed in the vacuum chamber based on the detection signal of the electron detector.

  Here, the temperature measurement unit includes an intensity measurement unit that measures the secondary electron intensity from the detection signal, and a temperature conversion unit that converts the secondary electron intensity detected by the secondary electron detector into a temperature. The temperature conversion unit converts the secondary electron intensity measured by the intensity measurement unit into temperature based on the correlation between the secondary electron intensity and the temperature obtained in advance. Thereby, the temperature of the substrate can be measured.

  The correlation between the secondary electron intensity and the temperature can be determined in an arbitrary format such as a table or an arithmetic expression, and the correlation between the secondary electron intensity and the temperature is stored in the storage unit or the calculation unit. I can leave.

  The temperature conversion unit performs conversion from the secondary electron intensity to the temperature by reading the temperature corresponding to the secondary electron intensity detected by the secondary electron detector from the storage unit. Alternatively, the temperature corresponding to the secondary electron intensity detected by the secondary electron detector is obtained by calculation, thereby converting the secondary electron intensity to the temperature.

  Further, the vacuum heating apparatus includes a stage on which the substrate is arranged, and the temperature measurement unit obtains a temperature distribution from the measurement position and the temperature by setting the irradiation position of the electron beam to the stage as the temperature measurement position.

  According to the present invention, the temperature of the heated substrate and the temperature distribution of the substrate can be measured.

  Further, according to the present invention, the temperature distribution of the substrate can be measured without requiring an additional device for temperature measurement.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram for explaining the configuration of a substrate inspection apparatus according to the present invention, and shows an example of an array substrate inspection apparatus. Here, a configuration example in which defect inspection is performed by irradiating a substrate with an electron beam and detecting secondary electrons generated from the substrate will be described.

  In FIG. 1, a substrate inspection apparatus 1 including a vacuum heating apparatus includes an electron gun 2 that generates an electron beam 21 that irradiates a substrate 30, a lens system 5 that deflects the electron beam 21 emitted from the electron gun 2, and a substrate. 30, a stage 4 that changes the irradiation position of the electron beam on the mounted substrate 30, a secondary electron detector 3 that detects secondary electrons 22 emitted from the substrate 30 by the irradiation of the electron beam 21, and The scanning control unit 8 controls the defect inspection unit 7 that performs defect inspection using the detection signal detected by the secondary electron detector 3, the lens system 5 and / or the stage 4, and scans the electron beam 21 with the substrate 30. With.

  A heater 9 is provided in the stage 4 as means for heating the substrate 30 placed on the stage 4. The heater may be provided not only in the stage 4 but also in other places in the vacuum chamber 20. Further, the heating means may be a lamp or the like in addition to the heater.

  Further, as a mechanism for measuring the temperature, a temperature measuring unit 10 is provided which receives a secondary electron detection signal from the secondary electron detector 3 and obtains the substrate temperature from the secondary electron detection signal. The temperature measurement unit 10 obtains the temperature distribution of the substrate by acquiring position information regarding the temperature measurement point from the scanning control unit 6.

  The inspection result of the defect inspection unit 7 and the temperature or temperature distribution of the temperature measurement unit 10 can be displayed on the display unit 8.

  The temperature measurement by the vacuum heating apparatus of the present invention is based on the correlation found between the intensity of secondary electrons emitted from the substrate when the substrate is irradiated with the electron beam and the temperature of the substrate at that time. is there. Therefore, it is necessary to obtain in advance a correlation between the temperature of the substrate and the intensity of secondary electrons detected at that temperature.

  FIG. 2 is a flowchart showing a procedure for obtaining a correlation between the temperature of the substrate and the secondary electron intensity. In the flowchart of FIG. 2, while heating the substrate (S1), secondary electrons obtained by irradiating the substrate with an electron beam are detected, and the intensity of the detected secondary electron signal is measured (S2). The temperature at this time is measured by a separately prepared temperature sensor. This temperature sensor is prepared for obtaining the correlation between the secondary electron intensity and the temperature, and after the correlation is obtained, it can be made unnecessary for the temperature measurement by the vacuum heating device. (S3).

  The correlation between the secondary electron intensity obtained in S2 and the temperature obtained in S3 is stored. This correlation is stored in a storage device in the form of a table or an arithmetic expression, and the temperature corresponding to the obtained secondary electron intensity is read out. (S4). The steps S1 to S4 are performed until the temperature measurement is completed while changing the temperature of the substrate (S5).

  Hereinafter, temperature measurement using the secondary electron detection signal by the temperature measurement unit will be described in two aspects. In the first aspect, the temperature is obtained after obtaining the two-dimensional array data on the secondary electron intensity of the substrate. In the second aspect, the temperature is measured while measuring the secondary electron intensity of the substrate by scanning. It is the aspect which calculates | requires sequentially.

  First, a 1st aspect is demonstrated using the block diagram of the temperature measurement part of FIG. 3, and the flowchart of FIG.

  In FIG. 3, the temperature measurement unit 10 includes an intensity measurement unit 11 that measures the intensity of the secondary electron detection signal input from the secondary electron detector 3, a temperature conversion unit 12 that converts the secondary electron intensity into temperature, A storage unit 13 that stores two-dimensional array data, a correlation between secondary electron intensity and temperature, and a display unit 8 that displays temperature and temperature distribution are provided.

  For example, the intensity measurement unit 11 obtains secondary electron intensity information by A / D converting the signal level of the secondary electron detection signal.

  The temperature conversion unit 12 converts the secondary electron intensity obtained by the intensity measurement unit 11 into a corresponding temperature using the correlation between the secondary electron intensity and the temperature.

  The storage unit 13 stores the secondary electron intensity information obtained by the intensity measurement unit 11 and the position information on the substrate from which the secondary electrons are obtained in the form of secondary array data, The storage unit 13b for storing the correlation between the secondary electron intensity and the temperature obtained in advance, the temperature information obtained by the temperature conversion unit 12, and the position information on the substrate from which the temperature information is obtained are stored in two. And a storage unit 13c that stores the data in the form of next sequence data.

  Here, the position information includes position information related to the position of the stage 4 and position information related to the deflection position of the lens system 5, and can be acquired from the scanning control unit 6. The positional information related to this scanning is the position of the electron beam 21 irradiated to the substrate 30 placed on the stage 4, but this position is also a position where secondary electrons are emitted, and at the same time a temperature measurement point. It is also a position corresponding to. Therefore, the position in the two-dimensional array data of the storage unit 13a and the storage unit 13b represents the same position on the substrate, and the position in the two-dimensional array data of the storage unit 13a represents a measurement point of secondary electrons. The position in the two-dimensional array data 13c represents a temperature measurement point.

  The flowchart of FIG. 4 mainly shows the operation of the temperature conversion unit 12. The temperature conversion unit 12 reads the secondary electron intensity from the two-dimensional array data stored in the storage unit 13a (S11), and sets the read secondary electron intensity to the corresponding temperature based on the correlation stored in the storage 13b. Conversion is performed (S12). The converted temperature information is stored as two-dimensional array data in the storage 13c together with the position information (S13).

  By repeating the steps S11 to S13 for all data stored in the two-dimensional array data stored in the storage unit 13a (S14), the temperature distribution in a predetermined region can be obtained and displayed on the display hand unit 8. (S15).

  In addition, the area | region of the two-dimensional arrangement | sequence data memorize | stored in the memory | storage part 13a can be made into the arbitrary areas defined on the board | substrate other than the whole surface of a board | substrate. Further, the range of the area read by the temperature conversion unit 12 from the storage unit 13a may be an arbitrary area in addition to the entire area stored in the storage unit 13a.

  Next, a 2nd aspect is demonstrated using the block diagram of the temperature measurement part of FIG. 5, and the flowchart of FIG.

  Since the configuration shown in FIG. 5 is substantially the same as the configuration shown in FIG. 3, the description of the common configuration is omitted here, and only the different configuration is described.

  The temperature conversion unit 12 sequentially inputs the intensity of the secondary electron detection signal measured by the intensity measurement unit 11, and converts the secondary electron intensity into temperature based on the correlation in the storage unit 13b. The converted temperature information is stored as two-dimensional array data in the storage unit 13c together with the position information.

  The flowchart in FIG. 6 mainly shows the operation of the temperature conversion unit 12. The temperature conversion unit 12 acquires the position information and the secondary electron detection signal (S21), obtains the intensity of the secondary electron signal by the intensity measurement unit 11, and sends it to the temperature conversion unit 12 (S22). The temperature conversion unit 12 receives the secondary electron intensity from the intensity measurement unit 11, and converts the secondary electron intensity into a corresponding temperature based on the correlation stored in the storage 13b (S23). The converted temperature information is stored as two-dimensional array data in the storage unit 13c together with the position information (S24).

  The display unit 8 displays the temperature information and the position information stored in the storage unit 13c on the display unit 8 (S25).

  By repeating the steps S21 to S25 for the measurement region (S26), the temperature distribution in the predetermined region can be obtained and displayed on the display hand 8.

  According to this aspect, the temperature can be obtained every time the secondary electron detection signal is obtained, and the temperature at the corresponding position can be sequentially displayed according to the scanning of the electron beam.

  The present invention can be applied to a liquid crystal substrate, an organic EL substrate, and the like.

It is a figure for demonstrating the structure of the board | substrate inspection apparatus of this invention. It is a flowchart which shows the procedure which calculates | requires the correlation between the temperature of a board | substrate, and secondary electron intensity. It is a block diagram for demonstrating the temperature measurement part of the 1st aspect of this invention. It is a flowchart for demonstrating operation | movement of the temperature measurement part of the 1st aspect of this invention. It is a block diagram for demonstrating the temperature measurement part of the 2nd aspect of this invention. It is a flowchart for demonstrating operation | movement of the temperature measurement part of the 2nd aspect of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate inspection apparatus, 2 ... Electron gun, 3 ... Secondary electron detector, 4 ... Stage, 5 ... Lens system, 6 ... Scan control part, 7 ... Defect inspection part, 8 ... Display part, 9 ... Heater, 10 DESCRIPTION OF SYMBOLS ... Temperature measurement part, 11 ... Strength measurement part, 12 ... Temperature conversion part, 13, 13a-13d ... Memory | storage part, 20 ... Vacuum chamber, 21 ... Electron beam, 22 ... Secondary electron, 30 ... Board | substrate.

Claims (6)

In a substrate inspection apparatus that performs defect inspection of a substrate by detecting secondary electrons obtained by irradiating the substrate with an electron beam, the temperature of the substrate in the vacuum heating apparatus of the substrate inspection apparatus comprising a vacuum chamber and a heating device A temperature measurement method for measuring
Obtaining secondary electron intensity emitted from the substrate by irradiation of the electron beam to the substrate disposed in the vacuum chamber;
A temperature measurement method in a substrate inspection apparatus , comprising: a step of obtaining a substrate temperature from the secondary electron intensity based on a correlation between secondary electron intensity and temperature obtained in advance. The method includes a step of obtaining an irradiation position of the electron beam on the substrate, obtaining a temperature distribution of the substrate from the measurement position and the temperature, using the irradiation position of the electron beam as a temperature measurement position. 2. A temperature measurement method in the substrate inspection apparatus according to 1. In a substrate inspection apparatus that performs defect inspection of a substrate by detecting secondary electrons obtained by irradiating the substrate with an electron beam,
A vacuum heating device comprising a vacuum chamber and a heating device ;
A secondary electron detector for detecting secondary electrons obtained from the substrate by irradiation with an electron beam;
Based on the detection signal of the secondary electron detector, and a temperature measuring unit for measuring the temperature of the substrate placed in said vacuum chamber,
The temperature measuring unit is
An intensity measuring unit for measuring secondary electron intensity from the detection signal;
A temperature conversion unit that converts the secondary electron intensity detected by the secondary electron detector into a temperature;
The temperature conversion unit converts the secondary electron intensity measured by the intensity measurement unit into a temperature based on a correlation between the secondary electron intensity and temperature obtained in advance, and the substrate inspection apparatus . A storage unit for storing a correlation between the secondary electron intensity and temperature;
The temperature conversion unit performs conversion from secondary electron intensity to temperature by reading a temperature corresponding to the secondary electron intensity detected by the secondary electron detector from a storage unit. 3. The substrate inspection apparatus according to 3. The temperature conversion unit calculates a temperature corresponding to the secondary electron intensity detected by the secondary electron detector by an arithmetic expression representing a correlation between the secondary electron intensity and the temperature, and calculates the secondary electron intensity from the secondary electron intensity. The substrate inspection apparatus according to claim 3, wherein conversion to temperature is performed. A stage on which the substrate is disposed;
The temperature measurement unit obtains a temperature distribution from the measurement position and the temperature, using the electron beam irradiation position on the stage as a temperature measurement position, according to any one of claims 3 to 5. The board | substrate inspection apparatus of description.

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