KR101138648B1 - 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; An optical sensor for detecting the second illumination light, an optical system provided on the 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 the substrate to reach the optical sensor, and introduced into the optical sensor A focus matching determination unit for determining whether the focus is matched through the first illumination light and a focus matching means for performing focusing between the optical system and the substrate upon receiving the focus misalignment signal, the optical system includes a movable optical system that is movable on the substrate plane. It includes.

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 using the same.

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. This has a problem of rising manufacturing costs.

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 board inspection method capable of obtaining autofocusing and review images at high speed for a moving specimen.

There is also a need for a substrate inspection apparatus and a substrate inspection method capable of obtaining autofocusing and review images while the inspection apparatus moves to an inspection region with respect to a moving specimen.

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; An optical sensor for sensing the first and second illumination lights; 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 the focus is matched through the first illumination light introduced into the optical sensor; And focusing means for performing focusing between the optical system and the substrate when receiving the focus misalignment signal of the focus matching determining unit, wherein the optical system includes a movable optical system that is movable on the substrate plane.

In addition, the first optical source may be coupled to the movable optical system to be movable on the substrate plane at the same time.

In addition, the first light source may be provided in the movable optical system such that the first illumination light reflected by reaching the substrate directly flows into the movable optical system.

The movable optical system may include an objective lens and an optical member positioned on an optical path of the first illumination light and the second illumination light to reflect light.

Also, when the inspection of one inspection region is completed, the movable optical system controller may be configured to control the movable optical system to move the objective lens in line with the inspection region to be inspected, based on the moving direction of the substrate.

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.

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

The apparatus may further include a substrate stage controller configured to control the substrate stage such 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 first illumination light.

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.

In addition, the focus matching determination unit may further include a second light source control unit for turning off the second light source when determining whether to focus.

The apparatus may further include a first light source controller to turn off the first light source while the second light source is detected by the optical sensor.

In addition, the optical sensor may be a common optical sensor for detecting both the first illumination light and the second illumination light.

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 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 A substrate inspection method using a substrate inspection apparatus including an optical system that is reflected from a substrate and guides the optical sensor, the method comprising: (a) analyzing a first illumination light reflected from the substrate and reaching the optical sensor to perform focus matching; Determining; (b) if it is determined that focus misalignment is performed, adjusting focus by controlling the optical system; And (c) when the focus adjustment is completed or determined to be in focus alignment, the second illumination light is reflected from the substrate to reach the optical sensor; And (d) the optical system includes a movable optical system and a fixed optical system that are movable on the substrate plane. After step (c), only the movable optical system is moved to the next inspection region to be inspected. In step) to (d), the substrate is moving.

In addition, by accessing the movable optical system to the inspection area of the substrate before or at the same time as the step (b), it is possible to determine whether the focus is coincident with the access to the inspection area and to complete the focus matching determination before the step (c). Step (e).

In addition, in the step (e), it may be a step of repeatedly irradiating the first illumination light at the same time as the approach to the inspection area, and repeatedly determining whether the focus match.

In addition, in the step (d), the movable optical system may be moved in the orthogonal direction using the moving direction of the substrate as a reference line to position the movable optical system on the same line as the next inspection region to be inspected.

In addition, the optical sensor includes a Charged Coupled Device (CCD), wherein the substrate image detected by the CCD is changed to be smaller than 1 pixel of the CCD during the duration of the ON state of the first illumination light of the first light source. The substrate stage may move the substrate.

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

In addition, the step (c) may be characterized in that the first light source is turned off while the second light source is detected by the optical sensor.

The method may further include storing inspection coordinates that need to be inspected in the substrate before step (a), and steps (a) to (d) may be performed with respect to the inspection coordinates.

The movable optical system is configured to reciprocate on the substrate surface, and when the whole optical system moves, there are many moving members, so it is inefficient in various aspects such as moving speed, operation accuracy, or energy efficiency. It is a moving structure. Accordingly, there is an effect that the substrate inspection can be more accurately and at high speed.

As the substrate is inspected while the substrate is being moved, the inspection efficiency can be improved since the degradation of the substrate inspection speed due to the operation of stopping and moving the substrate movement speed during the substrate inspection as in the prior art is prevented.

In addition, since the focus matching step is performed until the substrate inspection area is reached, the step of acquiring the substrate image may be performed immediately when the predetermined inspection area is reached, thereby reducing the time required for the inspection process.

The optical sensor of the present invention can also function as an optical sensor for receiving a laser, and at the same time can also function as an optical sensor for receiving illumination light, which is simpler than a configuration in which a conventional laser sensor and an illumination light sensor must be provided separately. It is possible to implement it, thereby reducing the labor cost and cost.

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.

3 to 5 are schematic diagrams of a high speed board inspection apparatus according to another 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 121a 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, a first optical member 113, a second optical member 115, and a tube lens 117. The first optical member 113 and the second optical member 115 may be provided as a prism, a half mirror or a beam splitter.

The first light source 123a may be positioned above the substrate S, and the first illumination light irradiated from the first light source 123a may directly reach and reflect the substrate S, and then may be the objective lens 111 and the first light source. The optical sensor 125 may be reached through the first optical member 113, the second optical member 115, and the tube lens 117.

4 is another embodiment, the first illumination light irradiated from the first light source 123c may reach the first optical member 113 and be reflected after passing through the second optical member 115. The first illumination light reflected by the first optical member 113 passes through the objective lens 111 and is reflected by the substrate S, and then again the objective lens 111, the first optical member 113, and the second optical member ( 115, the tube lens 117 may be sequentially passed to the optical sensor 125.

The tube lens 117 is provided to adjust to parallel light when the cross sectional area of the light is reduced or expanded.

When the first light sources 123a, 123b, 123c, and 123d are provided as laser light sources for measuring the focal length of the moving substrate S, the first light sources 123a, 123b, 123c, and 123d 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 sources 121a, 121b, 121c, and 121d irradiate 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 thereafter. The optical sensor 125 reaches through the photo sensor 125 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 optical system 110 may be provided as a movable optical system 118a and a fixed optical system 119 that are movable on a substrate plane. In the embodiment of FIG. 1, the first light source 123a is coupled to the movable optical system 118a and is movable together.

2 is a diagram showing the operation of the movable optical system of the high speed board inspection apparatus according to the present embodiment.

The movable optical system 118a has a configuration in which the movable optical system 118a can reciprocate on the substrate surface. When the whole optical system is moved, there are many moving members, so it is inefficient in various aspects such as moving speed, accuracy of operation, or energy efficiency, so that only the minimum components are moved. Accordingly, there is an effect that the substrate inspection can be more accurately and at high speed.

5 is another embodiment, when the first light source 123d and the second light source 121d are located behind the second optical member 115 to irradiate the first illumination light and the second illumination light, the first optical member 113. Reflected from the objective lens 111 reaches the configuration. In this case, the first light source 123d is coupled to the movable optical system 118d and does not need to move together.

As shown in FIG. 1, the movable optical system moving means 127 may be provided to move the objective lens 111 and the first optical member 113 in the Y-axis direction. The movable optical system operating means 127 may serve to move a part of the objective lens and the optical system to the position of the next substrate inspection region.

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

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

As shown in FIG. 1, only the objective lens 111, the first optical member 113, and the first light source 123a move in the Y-axis direction, and the second light source 121a is behind the second optical member 115. A second illumination light may be irradiated from the rear side of the second optical member 115.

3 is another embodiment, the movable optical system 118b is composed of an objective lens and a first optical member, the second light source 121b is fixed to the outside of the movable optical system 118b and the second illumination light through an optical fiber or the like. Is transmitted to irradiate the second illumination light toward the first optical member 113.

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 actuator that is electronically controlled, and the 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 may also function as an optical sensor for receiving a laser, and may 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 movable optical system control unit 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.

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

As shown in FIG. 6, first, the 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.

For this purpose, the movable optical system control unit is movable so that the objective lens, the first optical member, the second light source, and the first light source can be moved in the Y axis direction through the movable optical system moving means, and are positioned on the Y axis coordinate axis where the substrate inspection area is located. The optical system operating means can be controlled.

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, it is determined that the inspection area has been reached, the second light source is switched to the ON state by the illumination light source control unit, the first light source is turned to the OFF state, and the illumination light reflected from the substrate reaches the optical sensor to display the substrate image. Acquisition step S24 may proceed.

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, step S28 may be performed to determine whether there is a substrate inspection region to be inspected further. 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 movable optical system to the next substrate inspection region may be performed. Then, the process may proceed to step S16 again. Accordingly, the step of determining whether the focus registration is newly performed for each substrate inspection region may be performed.

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

 7 is a diagram illustrating a board inspection process by the high speed board inspection method according to the present embodiment.

As shown in FIG. 7, in step (A), it is determined whether the focus is matched in the first inspection area, and if it is determined that the focus is poor, the board image is photographed after the focus is adjusted. It can be moved downward by d1 to the second inspection area.

In this case, if the horizontal state of the substrate is uniform, only the focus adjustment may be performed once in the first inspection area, and only the substrate imaging step may be performed in the next inspection area.

The substrate stage is moved in the opposite direction of the X axis direction at a constant speed, during which the movable optical system is moved downward by d1 in the opposite direction of the Y axis by the movable optical system operating means.

When the substrate image is photographed in the second inspection area, the next inspection area may be moved upward by d2 to inspect the third inspection area.

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 is a diagram showing the operation of the movable optical system of the high speed board inspection apparatus according to the present embodiment.

3 to 5 are schematic diagrams of a high speed board inspection apparatus according to another embodiment.

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

7 is a diagram illustrating a board inspection process by the high speed board inspection method according to the present embodiment.

Claims (22)

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; An optical sensor including a sensor detecting the first illumination light and a sensor detecting the second illumination light; An optical system provided on an optical path between 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 optical system is a high speed substrate inspection apparatus including a movable optical system that can move to the inspection area that requires inspection on the substrate plane. The method of claim 1, And a first light source coupled to the movable optical system to simultaneously move on the substrate plane. 3. The method of claim 2, And the first light source is provided in the movable optical system such that the first illumination light reflected by reaching the substrate is introduced into the movable optical system. The method of claim 1, The movable optical system includes an objective lens and an optical member positioned on an optical path of the first illumination light and the second illumination light to reflect light. 5. The method of claim 4, And a movable optical system controller configured to control the movable optical system to move the objective lens on the same line as the next inspection region to be inspected, when the inspection of one inspection region is completed. 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. 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 8, And a substrate stage controller configured to control the substrate stage such that the substrate image sensed by the CCD changes smaller than one pixel of the CCD during the duration of the ON state of the first illumination light. 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 a second light source controller to turn off the second light source when the focus matching decision unit determines whether to focus. The method of claim 1, And a first light source controller to turn off the first light source while the second light source is detected by the optical sensor. The method of claim 1, The optical sensor is a high speed substrate inspection apparatus, characterized in that the common optical sensor for detecting both the first illumination light and the second illumination light. A substrate stage capable of loading and transferring a substrate, a first light source for irradiating a first illumination light for focusing to the substrate stage, a second light source for irradiating a second illumination light for acquiring a substrate image onto the substrate stage, and the first illumination light And an optical sensor for sensing 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, (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 misalignment is performed, adjusting focus by controlling the optical system; And (c) if 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; And (d) the optical system includes a movable optical system and a fixed optical system that are movable on the substrate plane, and after step (c), move only the movable optical system to the inspection region to be inspected next. The high speed board inspection method, characterized in that the substrate in the (a) to (d) step is moving. The method of claim 15, Approaching the inspection optical field of the substrate before or at the same time as the step (b), determining whether the focus is coincident with the access to the inspection area and completing the focus matching determination before the step (c). A high speed board inspection method comprising the step (e). The method of claim 16, In the case of step (e), the first substrate is irradiated with the first illumination light at the same time as the approach to the inspection area, and the step of determining whether the focus match repeatedly. The method of claim 15, In the step (d), the high speed substrate inspection comprises moving the movable optical system in the orthogonal direction using the moving direction of the substrate as a reference line to position the movable optical system on the same line as the next inspection region to be inspected. Way. The method of claim 15, The optical sensor includes a Charged Coupled Device (CCD), the substrate stage such that the substrate image sensed by the CCD changes smaller than 1 pixel of the CCD during the duration of the ON state of the first illumination light of the first light source. High speed substrate inspection method, characterized in that for moving the substrate. The method of claim 15, In the step (a), the first light source is turned off while determining whether the focus is matched. The method of claim 15, In the step (c), the first light source is turned off while the second light source is detected by the optical sensor. The method of claim 15, And storing the inspection coordinates to be inspected in the substrate prior to the step (a), wherein the steps (a) to (d) are performed on the inspection coordinates.

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