KR101138647B1 - High speed substrate inspection apparatus and method using the same - Google Patents

Abstract

The present invention relates to a high speed board inspection apparatus and a high speed board inspection method capable of autofocusing a moving substrate and at the same time obtaining a substrate image at a high speed. To this end, a substrate stage capable of loading and transporting a substrate, a first light source for irradiating a first stage illumination light for focusing the substrate stage, a second light source for irradiating a second stage illumination light for acquiring a substrate image, and a first illumination light; A common optical sensor for detecting both the second illumination light, an optical system provided on the optical path of the first illumination light and the second illumination light so as to reflect the first illumination light and the second illumination light from the substrate to reach the optical sensor, and an optical sensor And a focus matching unit configured to determine whether the focus is matched by the laser introduced into the focus matching unit, and a focus matching unit configured to perform focusing between the optical system and the substrate when the focus matching unit receives the focus matching unit.

Description

High speed board inspection device and high speed board inspection method using the same {HIGH SPEED SUBSTRATE INSPECTION APPARATUS AND METHOD USING THE SAME}

The present invention relates to a high speed board inspection apparatus and a high speed board inspection method.

In order to precisely inspect the substrate for defects, inspection is performed through an image enlarged by a high magnification camera.

In order to capture a portion of the substrate with a high magnification camera, the focus must be accurate to obtain a clear image.

 Focusing autofocusing operations can use a laser light source. When the image of the reflected laser reaches the sensor by irradiating the laser onto the substrate, it may be determined whether the focus is matched through the image of the laser detected by the sensor.

When the focus is achieved, the illumination light source is activated to capture an enlarged image by photographing the substrate surface through the camera.

In the prior art, a sensor for detecting an image of a laser used for an autofocusing operation and a camera for obtaining an enlarged image are separately required. In such a configuration, there is a problem that the manufacturing cost is increased.

In addition, substrate inspection is generally performed while the substrate is stopped. In other words, the substrate is moved to the inspection apparatus to stop and photographed, and then moved again to stop at the next inspection region and then photographed again.

Thus, the inspection progress in the stationary state has a problem that the inspection efficiency is lowered.

There is a need for a high speed board inspection apparatus and a high speed board inspection method capable of autofocusing on a moving specimen.

There is also a need for a high speed board inspection apparatus and a high speed board inspection method capable of acquiring autofocusing and review images using only one optical sensor.

Technical problems of the present invention are not limited to the above-mentioned technical problems, and other technical problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

According to another aspect of the present invention, there is provided a high speed board inspection apparatus comprising: a substrate stage capable of loading and transporting a substrate; A first light source for irradiating a focusing first illumination light to the substrate stage; A second light source for irradiating a second illumination light for acquiring a substrate image on the substrate stage; A common optical sensor for sensing both the first illumination light and the second illumination light; An optical system provided on an optical path of the first illumination light and the second illumination light to guide the first illumination light and the second illumination light to be reflected from a substrate to reach the optical sensor; A focus registration determination unit determining whether or not to focus through a laser introduced to the optical sensor; And focusing means for performing focusing between the optical system and the substrate when the focus misalignment signal is received.

In addition, the optical sensor may include a charged coupled device (CCD).

The apparatus may further include an inspection coordinate storage unit configured to store inspection coordinates requiring inspection on the substrate.

Also, when the focus matching signal is received, the substrate image acquisition unit converts the second illumination light reaching the optical sensor into an electrical signal to obtain a substrate image, and enlarges the substrate image obtained by the substrate image acquisition unit. The display unit may further include a display unit.

The optical system may be provided on an optical path from the first illumination light directly to the substrate to the optical sensor.

In addition, the first light source may be a laser light source for irradiating a laser.

In addition, the first light source may be a slit illumination light source for irradiating light in the form of a line.

The high speed board inspection method according to the present invention for solving the above problems includes a substrate stage capable of loading and transporting a substrate, a first light source for irradiating a first illumination light for focusing on the substrate stage, and acquiring a substrate image on the substrate stage. A second light source for irradiating the second illumination light, an optical sensor for detecting the first illumination light and the second illumination light, and an optical path of the first illumination light and the second illumination light, the first illumination light and the second illumination light In the substrate inspection method using a substrate inspection device comprising an optical system that is reflected from the substrate to guide the light sensor,

(a) determining a focus match by analyzing first illumination light reflected from the substrate and reaching the optical sensor;

(b) if it is determined that focus matching is poor, adjusting the focus by controlling the optical system; And

(c) if the focus adjustment is completed or determined to be in focus alignment, causing the second illumination light to be reflected from the substrate to reach the optical sensor;

The optical sensor used in the step (a) and the step (c) is a common optical sensor, characterized in that the substrate is moving in the step (a) to (c).

The method may further include storing inspection coordinates that need to be inspected in the substrate before the step (a).

In addition, in the steps (a) and (b), as the optical system approaches the stored inspection coordinates, the first light source continuously irradiates the pulsed illumination light and continuously determines whether or not the focus is matched. It may be a step to complete the focus registration.

In addition, after step (c), the method may further include displaying or recording an image of the substrate through the second illumination light induced by the optical sensor.

In addition, the optical sensor includes a Charged Coupled Device (CCD), and it is possible to determine whether or not the focus is matched through the image of the first illumination light reaching the CCD.

In addition, the substrate stage may move the substrate so that the substrate image sensed by the CCD is changed to be smaller than 1 pixel of the CCD during the duration of the ON state of the second illumination light of the second light source.

In addition, in the step (a), the first illumination light is directly irradiated onto the substrate, and the first illumination light reflected from the substrate may reach the optical sensor through the optical system.

In addition, in step (a), the second light source may be turned off while determining whether to focus.

In addition, step (c) may turn off the first light source while the second illumination light is detected by the optical sensor.

Autofocusing and substrate image acquisition can be performed by using one optical sensor, which reduces component parts and reduces labor, resulting in cost reduction and improved production efficiency.

In addition, since the inspection can be continued without stopping the substrate, the inspection efficiency is improved.

The technical effects of the present invention are not limited to the above-mentioned effects, and other technical effects not mentioned will be clearly understood by those skilled in the art from the following description.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present embodiment is not limited to the embodiments disclosed below, but can be implemented in various forms, and only this embodiment makes the disclosure of the present invention complete, and the scope of the invention to those skilled in the art. It is provided for complete information. Shapes of the elements in the drawings may be exaggerated parts for a more clear description, elements denoted by the same reference numerals in the drawings means the same element.

1 is a schematic configuration diagram of a high speed board inspection apparatus according to the present embodiment.

2 is a schematic diagram of a high speed board inspection apparatus according to another exemplary embodiment. The same reference numerals as in FIG. 1 perform similar functions, and thus redundant descriptions thereof will be omitted.

As shown in FIG. 1, the substrate S is placed on the substrate stage 101, and the substrate stage 101 is controlled by the substrate stage control unit 102 on the substrate surface, that is, on the XY plane in the X-axis direction or the Y-axis direction. It can have a structure to move the substrate (S). Or it may have a structure which moves the board | substrate S up and down in a Z-axis direction.

The first illumination light emitted from the first light source 123a and the second illumination light emitted from the second light source 121 may reach the optical sensor 125 through the optical system 110.

The first light source 123a may be a laser light source for irradiating a laser, or may be a slit illumination light source for irradiating a line-shaped light.

The optical system 110 may include an objective lens 111, an optical member 113, and a tube lens 117. The optical member 113 may be provided as a prism, a half mirror or a beam splitter.

The first illumination light emitted from the first light source 123a directly reaches and reflects the substrate S and passes through the objective lens 111, the optical member 113, and the tube lens 117 to reach the optical sensor 125. can do.

The second illumination light irradiated from the second light source 121 is reflected by the optical member 113 and passes through the objective lens 111, and then is reflected by the substrate S to be again reflected by the objective lens 111, the optical member 113, The light sensor 125 may be passed through the tube lens 117.

2 is another embodiment, the first illumination light emitted from the first light source 123b and the second illumination light emitted from the second light source 121 are respectively reflected by the optical member 113 to pass through the objective lens 111. After the light is reflected from the substrate S, the light may be passed through the objective lens 111, the optical member 113, and the tube lens 117 to reach the optical sensor 125.

The tube lens 117 may be provided to be adjusted to parallel light when the cross-sectional area of the light is reduced or expanded, and may be appropriately disposed at other positions on the light path.

When the first light sources 123a and 123b are provided as laser light sources for measuring the focal length of the moving substrate S, the first light sources 123a and 123b may emit laser pulses having a short period or a short duration. Depending on the situation, various laser pulses may be irradiated, and may be arranged to have a period of approximately 600 Hertz or have a duration of several tens of microseconds.

The second light source 121 irradiates the second illumination light when the focus is matched, and the second illumination light reaches the substrate S through the optical system 110 and is reflected, and then again passes through the optical system 110 through the optical sensor 110. 125 is reached to provide an image of the substrate (S).

In order to clearly capture the image of the moving substrate S, the shutter speed may be set relatively fast, and thus the duration of the second illumination light may last only a few microseconds. The second light source may be provided with strobe type illumination.

As shown in FIG. 1, the entire optical system 110 may be provided to be movable on a substrate plane. In the embodiment of FIG. 1, the first light source 123a is coupled to the optical system and is movable together.

The optical system operating means 127 may be provided to move the objective lens 111, the tube lens 117, and the optical member 113 in the Y-axis direction.

In some cases, it may be provided to be movable in the X direction or the Z axis direction. The optical system driving means 127 may be provided to include an electronically controlled actuator or the like.

On the other hand, the optical system control unit 137 for controlling the optical system operating means 127 may be provided.

Focus matching means 126 may be provided to move the objective lens 111 up and down in the Z-axis direction for focus matching. The focus matching means 126 may be provided to include an electronically controlled actuator and the like, and a focus matching means controller 136 may be provided to control the focus matching means 126.

In another embodiment, the movable optical system actuating means may be configured to function as a focusing means.

The optical sensor 125 may be provided as a charged coupled device (CCD). A CCD is a sensor that converts light into electric charges to obtain an image. A CCD chip can be made up of many photodiodes, and the amount of electrons of the corresponding diode means brightness of light depending on the amount of light irradiated to each diode.

Accordingly, the optical sensor 125 of the present embodiment can also function as an optical sensor for receiving a laser, and can also function as an optical sensor for receiving a general strobe type LED, xenon lamp, and the like. Therefore, the conventional laser sensor and the illumination light sensor can be more simply implemented than the configuration that must be provided separately, thereby reducing the labor and cost.

The operation of the optical sensor 125 is controlled by the optical sensor control unit 135, and a signal of the optical sensor 125 may be sent to the focus matching determination unit 138 in order to check whether focus matching is performed.

 When a signal indicating that the focus match is good in the focus match determination unit 138 is generated, the electrical signal generated by the illumination light reaching the optical sensor 125 is transferred to the substrate image acquisition unit 134.

 When a signal indicating that the focus matching is bad is generated by the focus matching determination unit 138, a signal may be sent to the focus matching means controller 136 to induce the control of the focus matching means 126 again.

The inspection coordinate storage unit 132 may store the coordinates of the inspection area to be irradiated in advance and provide position information to the optical system controller 137 to transmit a signal for the control amount.

In addition, the central processing unit 139 determines whether the objective lens has reached the inspection area and performs other comprehensive control.

3 is a flowchart illustrating a high speed board inspection method according to the present embodiment.

As shown in FIG. 3, first, a step (S10) of storing the coordinates of the substrate inspection region in the inspection coordinate storage unit 132 may be performed. The other substrate inspection apparatus may also receive the general substrate defects and receive electronically coordinates for the area determined to be further detailed.

Next, step S12 of moving the substrate may be performed. The movement of the substrate can be maintained until the end of the substrate inspection. The moving speed of the substrate may be maintained at a constant speed. As a result, the degradation of the substrate inspection speed due to the operation of stopping and moving the substrate movement speed again during the substrate inspection may be prevented, thereby improving inspection efficiency.

In addition, the movable optical system is moved to the stored substrate inspection area, and at the same time, a step (S14) of irradiating a laser pulse as the first illumination light may be performed while the first light source is turned on.

To this end, the optical system can be moved in the Y-axis direction through the optical system operating means, and the optical system control unit can control the optical system operating means to be positioned on the Y-axis coordinate axis where the substrate inspection region is located.

In the first light source, the irradiated laser pulse is reflected from the substrate to reach the optical sensor.

Next, the step S16 of determining whether the focus is matched may be performed. If it is determined that the focus misalignment in step S16, it can proceed to step S18 to perform the focus adjustment again.

In the focus matching decision unit, a general focus matching determination algorithm may be executed. For example, the focus matching determination unit may determine whether the focus matching is performed by analyzing the position and the degree of change of the line-shaped laser image formed by compressing the laser image in one direction. have.

Next, if it is determined in step S16 that the focus is matched, the step S20 of determining whether the stored substrate inspection area has been reached may proceed.

If it is determined that it has not reached, it continues to move to the stored inspection area (S22).

Until the stored inspection area is reached, the first light source continuously irradiates the laser pulses and determines whether the focus alignment is continued (S16).

As a result, the step of acquiring the substrate image may be performed immediately upon reaching the predetermined inspection area, thereby reducing the time required for the inspection process.

Next, when it is determined that the inspection area has been reached, the second light source is turned on by the illumination light source controller, the first light source is turned off, and the illumination light reflected from the substrate reaches the optical sensor to obtain a substrate image. Step S24 may be performed.

In this case, the second light source can irradiate the second illumination light and move the substrate stage such that the substrate image detected by the CCD changes smaller than 1 pixel of the CCD during the duration of the ON state of the second illumination light. You can adjust the speed and shutter speed. As a result, the substrate image can be recorded clearly even while moving.

Next, an electrical signal for the image of the substrate obtained by reaching the optical sensor may be displayed through the display unit 141 or sent to the storage device 143 to store the electrical signal (S26).

Next, a step S28 of determining whether there is a substrate inspection region to be additionally inspected may be performed. The inspection coordinate storage unit 132 may be performed in a manner of determining whether there are unchecked coordinates among the inspection coordinates.

 In this case, when there is a substrate inspection region to be additionally inspected, a step (S30) of moving the optical system to the next substrate inspection region may be performed. Then, the process may proceed to step S16 again. Therefore, the laser pulse is continuously irradiated while moving to the next inspection area to determine whether the focus is matched continuously.

If there is no substrate inspection region to be inspected further, the inspection can be terminated.

An embodiment of the present invention described above and illustrated in the drawings should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art will be able to modify the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the scope of the present invention as long as they are obvious to those skilled in the art.

1 is a schematic configuration diagram of a high speed board inspection apparatus according to the present embodiment.

2 to 4 is a schematic configuration diagram of a high speed board inspection apparatus according to another embodiment.

5 is a flowchart illustrating a high speed board inspection method according to the present embodiment.

Claims (16)

A substrate stage capable of loading and transferring a substrate; A first light source for irradiating a focusing first illumination light to the substrate stage; A second light source for irradiating a second illumination light for acquiring a substrate image on the substrate stage; A common optical sensor provided to serve as both a sensor for detecting the first illumination light and a sensor for detecting the second illumination light; An optical system provided on an optical path of the first illumination light and the second illumination light to guide the first illumination light and the second illumination light to be reflected from a substrate to reach the optical sensor; A focus matching determination unit determining whether or not focus matching is performed through the first illumination light introduced into the optical sensor; And And focus matching means for performing focusing between the optical system and the substrate when receiving the focus misalignment signal of the focus matching determination unit. The method of claim 1, The optical sensor is a high speed substrate inspection device comprising a CCD (Charged coupled device). The method of claim 1, High speed substrate inspection apparatus further comprises an inspection coordinate storage unit for storing the inspection coordinates that need to be inspected on the substrate. The method of claim 1, When receiving the focus matching signal of the focus matching determination unit, the substrate image acquisition unit for converting the second illumination light reaching the optical sensor into an electrical signal to obtain a substrate image and to enlarge and display the substrate image obtained by the substrate image acquisition unit High speed substrate inspection device further comprising a display unit. The method of claim 1, And an optical system provided on the optical path from the first illumination light directly to the substrate to the optical sensor. The method of claim 1, And said first light source is a laser light source for irradiating a laser. The method of claim 1, The first light source is a high speed substrate inspection apparatus, characterized in that the slit illumination light source for irradiating light in the form of a line. A substrate stage capable of loading and transferring a substrate, a first light source for irradiating a first illumination light for focusing on the substrate stage, a second light source for irradiating a second illumination light for acquiring a substrate image on the substrate stage, and the first light source; An optical sensor for detecting an illumination light and a second illumination light, and an optical system provided on an optical path of the first illumination light and the second illumination light to guide the first illumination light and the second illumination light to be reflected from a substrate to reach the optical sensor. In the substrate inspection method using a substrate inspection apparatus to (a) determining a focus match by analyzing first illumination light reflected from the substrate and reaching the optical sensor; (b) if it is determined that focus matching is poor, adjusting the focus by controlling the optical system; And (c) if the focus adjustment is completed or determined to be in focus alignment, causing the second illumination light to be reflected from the substrate to reach the optical sensor; The optical sensor used in the step (a) and the step (c) is a common optical sensor, the high-speed substrate inspection method, characterized in that the substrate is moving in the step (a) to (c). The method of claim 8, And storing the inspection coordinates requiring inspection in the substrate before step (a). 10. The method of claim 9, In the steps (a) and (b), the optical system approaches the stored inspection coordinates and the first light source continuously irradiates the pulsed illumination light and continuously determines whether the focus is matched, thereby focusing before the step (c). A high speed board inspection method, characterized in that the step of completing the matching. The method of claim 8, After the step (c), further comprising the step of displaying or recording the image of the substrate through the second illumination light guided to the optical sensor. The method of claim 8, The optical sensor includes a Charged Coupled Device (CCD), and determines whether the focus is matched through the image of the first illumination light that reaches the CCD. The method of claim 12, And the substrate stage moves the substrate such that the substrate image sensed by the CCD changes less than one pixel of the CCD during the duration of the ON state of the second illumination light. The method of claim 8, In the step (a), the first illumination light is directly irradiated to the substrate and the first illumination light reflected from the substrate reaches the optical sensor through the optical system. The method of claim 8, In the step (a), the second light source is turned off while determining whether the focus is matched. The method of claim 8, In the step (c), the first light source is turned off while the second illumination light is detected by the optical sensor.

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