CN220251771U - Optical detection system - Google Patents

Abstract

The embodiment of the invention discloses an optical detection system which is used for synchronously improving the efficiency and the precision of defect detection in a detection area. An optical detection system in an embodiment of the present invention includes: the area array optical detection system comprises a first light source, a plurality of objective lenses with different multiplying powers and an area array detection camera, wherein the first light source is used for providing light beams, the plurality of objective lenses with different multiplying powers are used for imaging a detection area of a detection object, and the area array detection camera is used for scanning the detection area frame by frame; the linear array optical detection system comprises a second light source, a single-magnification objective lens and a linear array detection camera, wherein the second light source is used for providing light beams, the single-magnification objective lens is used for imaging a detection area of a detection object, and the linear array detection camera is used for scanning a progressive image of the detection area; the area array optical detection system and the linear array optical detection system are matched with each other to realize defect detection on images scanned line by line and images scanned frame by frame in a detection area.

Description

Optical detection system

Technical Field

The invention relates to the technical field of detection, in particular to an optical detection system.

Background

In semiconductor manufacturing, defects on wafers need to be detected to ensure process yield or quality. In the existing wafer inspection, the wafer is generally scanned and inspected by a linear array optical inspection system or scanned and inspected by an area array optical inspection system.

When the wafer is inspected, the two methods often have the problems of low inspection efficiency and low inspection precision.

Disclosure of Invention

The embodiment of the invention provides an optical detection system which is used for controlling the mutual coordination of a linear array optical detection system and an area array optical detection system to scan and detect a detection area of a detection object, thereby improving the detection efficiency and the detection precision of the detection object.

An embodiment of the present application provides an optical detection system, including:

the area array optical detection system comprises a first light source, a plurality of objective lenses with different multiplying powers and an area array detection camera, wherein the first light source is used for providing light beams for irradiating a detection object at a preset angle, the plurality of objective lenses with different multiplying powers are used for imaging a detection area of the detection object with different multiplying powers, and the area array detection camera is used for scanning the detection area frame by frame;

the linear array optical detection system comprises a second light source, a single-magnification objective lens and a linear array detection camera, wherein the second light source is used for providing a light beam for irradiating a detection object at a preset angle, the single-magnification objective lens is used for carrying out single-magnification imaging on a detection area of the detection object, and the linear array detection camera is used for carrying out progressive image scanning on the detection area;

The control unit is used for controlling the area array optical detection system and the linear array optical detection system to be matched with each other so as to realize frame-by-frame image scanning and line-by-line image scanning of the detection area and detect defects of the frame-by-frame scanned image and the line-by-line scanned image.

In an embodiment, the detection area of the detection object has a coordinate axis, the detection object is placed on the stage, and the stage also has a coordinate axis, and the control unit is specifically configured to:

controlling the area array optical detection system to scan an image of a detection area of a detection object positioned on the objective table;

judging whether the coordinate axis of the detection area is parallel to the coordinate axis of the objective table according to the scanned image of the detection area;

if yes, triggering the area array optical detection system to start scanning the image of the detection area frame by frame, and/or triggering the linear array optical detection system to start scanning the image of the detection area line by line.

In an embodiment, the control unit is specifically configured to:

controlling the linear array optical detection system to perform row-by-row image scanning on a detection area of the detection object by utilizing the single-magnification objective lens;

Performing defect detection on the progressively scanned images;

if a defect is detected in the image, controlling the area array optical detection system to perform frame-by-frame image scanning again on a target detection area where the defect is located by using a target objective, wherein the multiplying power of the target objective is larger than that of the single-multiplying-power objective;

and performing defect detection again on the scanned image frame by frame.

In an embodiment, the control unit is specifically configured to:

controlling the linear array optical detection system to perform row-by-row image scanning on a detection area of the detection object by utilizing the single-magnification objective lens;

performing defect detection with first precision on the progressively scanned image;

controlling the area array optical detection system to perform image scanning on a detection area of the detection object frame by utilizing a target objective, wherein the multiplying power of the target objective is larger than that of the single-multiplying-power objective;

and performing defect detection with a second precision on the scanned image frame by frame, wherein the second precision is larger than the first precision.

In an embodiment, the area array detection camera is a black-and-white camera, and the area array optical detection system further comprises a color camera, wherein the color camera is arranged in a direction parallel to the black-and-white camera through a spectroscope and a reflector.

In an embodiment, the control unit is specifically configured to:

when a defect is detected in an image scanned by the linear array optical detection system, moving a target detection area where the defect is located to be under a target objective lens of the area array optical detection system, wherein the magnification of the target objective lens is larger than that of the objective lens with single magnification;

and controlling the color camera in the area array optical detection system to scan the image of the target detection area.

In an embodiment, the control unit is specifically configured to:

when a defect is detected in a black-and-white image scanned in the area array optical detection system, controlling the color camera in the area array optical detection system to perform image scanning on a target detection area where the defect is located;

or,

in the area array optical detection system, the area array detection camera and the color camera are controlled to synchronously scan the detection area of the detection object.

In an embodiment, the first light source includes a first annular light source, the second light source includes a second annular light source, and a first plane in which the first annular light source is located and a second plane in which the second annular light source is located are both parallel to a plane in which the detection object is located;

The area array optical detection system further comprises a third light source, wherein the third light source comprises a first bright field light source, the first bright field light source is arranged in a third plane perpendicular to the first plane, the first bright field light source is coaxially arranged with the optical axis of the first annular light source through a reflector and a spectroscope, and the first bright field light source is used for providing a light beam for vertically irradiating a detection area in the detection object;

the linear array optical detection system further comprises a fourth light source, the fourth light source comprises a second bright field light source, the second bright field light source is arranged in a fourth plane perpendicular to the second plane, the second bright field light source is coaxially arranged with the optical axis of the second annular light source through a reflector and a spectroscope, and the second bright field light source is used for providing light beams for perpendicularly irradiating a detection area in the detection object.

In an embodiment, the first light source includes a first bright field light source that vertically irradiates the detection area, the second light source includes a second bright field light source that vertically irradiates the detection area, and the first bright field light source and the second bright field light source both provide light beams that vertically irradiate the detection area through a reflector and a spectroscope, respectively;

The area array optical detection system further comprises a third light source, wherein the third light source comprises a first annular light source, a first plane where the first annular light source is located is parallel to a plane where the detection object is located, the first plane is perpendicular to the plane where the first bright field light source is located, and an optical axis of the first annular light source and a light beam of the first bright field light source irradiating the detection area are coaxially arranged;

the linear array optical detection system further comprises a fourth light source, the fourth light source comprises a second annular light source, a second plane where the second annular light source is located is parallel to a plane where the detection object is located, the second plane is perpendicular to the plane where the second bright field light source is located, and an optical axis of the second annular light source and a light beam of the second bright field light source irradiating the detection area are coaxially arranged.

In an embodiment, the area array optical detection system further comprises a first autofocus sensor, and the linear array optical detection system further comprises a second autofocus sensor;

the first automatic focusing sensor is arranged in a plane where the first bright field light source is located through a spectroscope and a reflecting mirror and is perpendicular to the optical axis of the first bright field light source, and the first automatic focusing sensor is used for changing the distance between the detection area of the detection object and the plurality of objective lenses with different multiplying powers so as to realize clear imaging of the plurality of objective lenses with different multiplying powers and the area array detection camera on the detection area in the detection object;

The second automatic focusing sensor is arranged in a plane where the second bright field light source is located through a spectroscope and a reflecting mirror and is perpendicular to the optical axis of the second bright field light source, and the second automatic focusing sensor is used for changing the distance between different detection areas of the detection object and the single-magnification objective lens so as to realize clear imaging of the single-magnification objective lens and the linear array detection camera on different detection areas in the detection object.

In an embodiment, the area array optical detection system further includes a first light intensity monitor, where the first light intensity monitor is disposed in a plane where the first bright field light source is located through a reflector and a spectroscope, and in a direction perpendicular to an optical axis of the first bright field light source, so as to monitor a light intensity of the first bright field light source, so as to ensure that the light intensity of the first bright field light source is within a preset light intensity range;

the linear array optical detection system further comprises a second light intensity monitor, wherein the second light intensity monitor is arranged in a plane where the second bright field light source is located through a reflector and a spectroscope and is perpendicular to the optical axis of the second bright field light source, so that the light intensity of the second bright field light source is monitored, and the light intensity of the second bright field light source is ensured to be within a preset light intensity range.

In an embodiment, the area array optical detection system further includes a first filter wheel disposed along a direction of a light beam emitted by the first bright field light source, where a plurality of optical filters are disposed in the first filter wheel to screen light waves of a preset wave band from the first bright field light source;

the linear array optical detection system further comprises a second filter wheel arranged along the direction of the light beam emitted by the second bright field light source, wherein a plurality of optical filters are arranged in the second filter wheel so as to screen light waves with preset wave bands from the second bright field light source.

In an embodiment, the control unit is specifically configured to:

controlling a first light source and the third light source in the area array optical detection system to irradiate a detection area of the detection object at the same time;

controlling the area array detection camera to simultaneously perform image scanning on a detection area irradiated by the first light source and the third light source so as to simultaneously acquire a dark field image and a bright field image of the detection area;

or alternatively, the first and second heat exchangers may be,

controlling a second light source and the fourth light source in the linear array optical detection system to irradiate a detection area of the detection object at the same time;

and controlling the linear array detection camera to simultaneously perform image scanning on the detection area irradiated by the second light source and the fourth light source so as to simultaneously acquire a dark field image and a bright field image of the detection area.

In an embodiment, the area array optical detection system further includes a first optical filter disposed between the plurality of objective lenses with different magnifications and the area array detection camera along the optical axis direction of the first annular light source, for screening out a target wavelength sensitive to the detection object;

the linear array optical detection system further comprises a second optical filter arranged between the Shan Beilv objective lens and the linear array detection camera along the optical axis direction of the second annular light source, and the second optical filter is used for screening out target wavelengths sensitive to the detection object.

In one embodiment, the second light source comprises a strobe xenon lamp.

In an embodiment, the control unit is specifically configured to:

controlling the product of the exposure time of the area array detection camera and the movement speed of the detection object in the scanning direction to be not more than the preset image resolution precision;

and controlling the product of the stroboscopic period of the stroboscopic xenon lamp and the movement speed of the detection object in the scanning direction to be not more than the height of a single frame image scanned by the area array detection camera in the scanning direction.

In an embodiment, the area array optical detection system further includes an objective turntable, the plurality of objective lenses with different magnifications are mounted on the objective turntable, and the objective turntable switches the objective lenses with different magnifications when moving along a circle, so that the objective lenses image the detection area of the detection object with different magnifications;

Or,

the area array optical detection system further comprises a linear movement module, wherein a plurality of objective lenses with different multiplying powers are installed on the linear movement module, and the objective lenses with different multiplying powers are switched when the linear movement module moves along a straight line, so that the objective lenses image the detection area of the detection object with different multiplying powers.

In an embodiment, when the detection object is a COMS image sensor, the incident angles of the first and second ring light sources include 30 to 60 degrees.

From the above technical solutions, the embodiment of the present invention has the following advantages:

the optical detection system provided in the embodiment of the application includes: the system comprises an area array optical detection system and a linear array optical detection system, wherein the area array optical detection system comprises a first light source, a plurality of objective lenses with different multiplying powers and an area array detection camera, the first light source is used for providing light beams for irradiating a detection object at a preset angle, the plurality of objective lenses with different multiplying powers are used for imaging a detection area of the detection object with different multiplying powers, and the area array detection camera is used for scanning the detection area frame by frame; the linear array optical detection system comprises a second light source, a single-magnification objective lens and a linear array detection camera, wherein the second light source is used for providing a light beam for irradiating a detection object at a preset angle, the single-magnification objective lens is used for carrying out single-magnification imaging on a detection area of the detection object, and the linear array detection camera is used for carrying out progressive image scanning on the detection area; the control unit is used for controlling the area array optical detection system and the linear array optical detection system to be matched with each other so as to realize progressive image scanning and frame-by-frame image scanning of the detection area and defect detection of the progressive scanned image and the frame-by-frame scanned image.

Because the control unit in the optical detection system of the embodiment of the application can control the area array optical detection system and the linear array optical detection system to be matched with each other, the single-magnification objective lens in the linear array optical detection system has a large field angle and a large scanning range at a time, so that the detection efficiency can be improved, the magnification objective lens in the area array optical detection system is larger than the magnification objective lens in the linear array optical detection system, the field angle is small, more detail information can be seen at a time, and the detection precision can be improved.

Drawings

FIG. 1 is a schematic diagram of an embodiment of an optical detection system according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a frame-by-frame image scan and a line-by-line image scan in an embodiment of the present application;

FIG. 3 is a schematic diagram of another embodiment of an optical detection system according to an embodiment of the present application;

FIG. 4 is a schematic diagram of another embodiment of an optical detection system according to an embodiment of the present application;

FIG. 5 is a schematic diagram of another embodiment of an optical detection system according to an embodiment of the present application;

FIG. 6 is a schematic diagram of another embodiment of an optical detection system according to an embodiment of the present application;

FIG. 7 is a schematic diagram of another embodiment of an optical detection system according to an embodiment of the present application;

fig. 8 is a schematic diagram of another embodiment of an optical detection system according to an embodiment of the present application.

Detailed Description

The embodiment of the invention provides an optical detection system which is used for improving the detection efficiency and the detection precision of a detection object at the same time.

In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.

The terms first, second, third, fourth and the like in the description and in the claims and in the above drawings are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments described herein may be implemented in other sequences than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

For convenience of understanding, the optical detection system in the embodiment of the present application will be described below with reference to fig. 1, where the optical detection system in the embodiment of the present application includes:

the area array optical detection system 10 comprises a first light source 101, a plurality of objective lenses 102 with different multiplying powers, and an area array detection camera 103, wherein the first light source 101 is used for providing a light beam for irradiating a detection object at a preset angle, the plurality of objective lenses 102 with different multiplying powers are used for imaging a detection area of the detection object with different multiplying powers, and the area array detection camera 103 is used for scanning the detection area frame by frame;

the linear array optical detection system 20 comprises a second light source 201, a single-magnification objective 202 and a linear array detection camera 203, wherein the second light source 201 is used for providing a light beam for irradiating a detection object at a preset angle, the single-magnification objective 202 is used for carrying out single-magnification imaging on a detection area of the detection object, and the linear array detection camera 203 is used for carrying out progressive image scanning on the detection area;

the control unit 30 is configured to control the planar array optical detection system 10 and the linear array optical detection system 20 to cooperate with each other to perform progressive image scanning and frame-by-frame image scanning on the detection area, and perform defect detection on the progressive scanned image and the frame-by-frame scanned image.

The imaging process of the detection area will be described below by taking an area array optical detection system as an example:

specifically, in the embodiment of the present application, the detection object may be a wafer, glass, a chip, a mask, or the like, which is not specifically limited herein, after the first light source 101 irradiates the detection area of the detection object at a preset angle, the signal light is incident into the target objective 102 (the target objective is any one of a plurality of objective lenses with different magnifications), so that the target objective 102 images the detection area, and the area array detection camera 103 is used for scanning the frame-by-frame image of the detection area, where the area array detection camera may be a CCD or an ICCD, or the like, which is not specifically limited herein.

Further, the first light source in the area array optical detection system and the second light source in the line array optical detection system may be LEDs, LCD lamps, or other forms of light sources, as long as a light beam irradiating the detection object at a preset angle can be provided, and the forms of the first light source and the second light source are not particularly limited herein.

In an area array optical detection system, as an alternative embodiment, a plurality of objective lenses 102 with different magnifications may be mounted on an objective lens turntable, and the objective lens turntable may switch the objective lenses with different magnifications when moving along a circle, so that the objective lens performs imaging with different magnifications on a detection area.

As another alternative embodiment, a plurality of objective lenses with different magnifications may be further mounted on the linear movement module, and the linear movement module switches the objective lenses with different magnifications when moving along the linear direction, so that the objective lenses image the detection area with different magnifications.

For easy understanding, fig. 2 shows a schematic diagram of performing a frame-by-frame image scan on the detection area, i.e., a scan unit is a frame, and performing a line-by-line image scan on the detection area, i.e., a scan unit is a line, and only one line of image can be obtained at a time.

Based on the optical detection system in the embodiment of fig. 1, a description is given below of how the control unit 30 controls the process of the mutual cooperation of the area array optical detection system and the line array optical detection system:

in one embodiment, assuming that the inspection object is a wafer, the control unit 30 levels the wafer by using an area array optical inspection system, and then further performs defect inspection on the inspection area in the wafer by using the area array optical inspection system or the linear array optical inspection system.

In this embodiment of the present application, the wafer is engraved with a small lattice (which may be regarded as the coordinate axis of the wafer) in advance, so that the position of the wafer is conveniently located, when the detection area of the wafer is scanned by the area array optical detection system or the linear array optical detection system, the wafer is generally placed on a flat objective table, and the coordinate axis is also preset on the objective table, so that the position of the wafer is conveniently located on the objective table, the coordinate axis of the wafer and the coordinate axis on the objective table generally need to be leveled, that is, the coordinate axis on the control wafer is parallel to the coordinate axis of the objective table.

Therefore, in this embodiment, the control unit first controls the area array optical detection system to scan the detection area of the detection object located on the stage, and determines whether the coordinate axis of the detection area is parallel to the coordinate axis of the stage according to the scanned image of the detection area, and if the coordinate axes are parallel to each other, triggers the area array optical detection system to start scanning the detection area with a frame-by-frame image, and/or triggers the line array optical detection system to start scanning the detection area with a line-by-line image.

Because the area array optical detection system can scan one frame of image at a time, the leveling speed can be improved relative to the linear array optical detection system in the leveling process.

Next, a description is given of how the control unit 30 controls the process of the mutual cooperation of the area array optical detection system and the line array optical detection system:

in an embodiment, because the single-magnification objective lens in the linear array optical detection system has a large field angle, a single-time scannable range is large, and the large-magnification objective lens (compared with the single-magnification objective lens in the linear array optical detection system) in the area array optical detection system has a small field angle, the single-time scannable range is small, the control unit can control the linear array optical detection system to quickly scan the detection object first, and then, when the defect is detected, the large-magnification objective lens in the area array optical detection system is utilized to perform detail scanning and defect detection on the detection area where the defect is located.

Specifically, the control unit 30 controls the linear array optical detection system to perform image scanning on the detection area of the detection object row by using the single-magnification objective lens, and performs defect detection on the image scanned row by row; if the defect is detected in the image, controlling the area array optical detection system to scan the target detection area where the defect is located by using the target objective again frame by frame, wherein the multiplying power of the target objective is larger than that of the Shan Beilv objective; and performing defect detection again on the scanned image frame by frame.

It should be noted that, in the embodiment of the present application, the detection object is driven to switch between the area array optical detection system and the linear array optical detection system by the movement of the objective table.

Next, a description is given of how the control unit 30 controls the process of the mutual cooperation of the area array optical detection system and the line array optical detection system:

in an embodiment, because the single-magnification objective lens and the multi-magnification objective lens have different accuracy of defects, for example, it is assumed that the single-magnification objective lens can only detect defects of 10um, and the multi-magnification objective lens can detect defects of less than 10um by switching objective lenses of different magnifications, it is assumed that the objective lens of maximum magnification can detect defects of 2um at minimum, and for different detection objects, there may be defects of both 10um and 2um, in order to realize simultaneous detection of the two defects, the control unit in the embodiment of the present application may:

The control linear array optical detection system utilizes a single-magnification objective lens to scan the detection area of the detection object row by row, performs defect detection of first precision on the image scanned row by row, and utilizes a target objective lens to scan the detection area of the detection object frame by frame, wherein the magnification of the target objective lens is larger than that of the Shan Beilv objective lens, and performs defect detection of second precision on the image scanned frame by frame, and the second precision is larger than the first precision.

According to the embodiment of the application, the detection object is driven to switch between the area array optical detection system and the linear array optical detection system through the movement of the object stage, and the detection of different precision of the detection area in the detection object is realized through controlling the cooperative work of the area array optical detection system and the linear array optical detection system.

Based on the area array optical detection system 10 in the embodiment of fig. 1, where the area array detection camera 103 is a black-and-white camera, in an actual detection scene, in order to obtain a more stereoscopic image of a defect, the embodiment of the present application further provides a color camera 104 in the area array optical detection system, where the color camera 104 is disposed in a direction parallel to the black-and-white camera through a beam splitter and a reflecting mirror.

For ease of understanding, fig. 3 shows a schematic diagram of the optical path of an area array optical detection system including a color camera.

Next, a description is given of how the control unit 30 controls the process of the mutual cooperation of the area array optical detection system and the line array optical detection system:

in an embodiment, the control unit is specifically configured to:

when a defect is detected in an image scanned by the linear array optical detection system, moving a target detection area where the defect is positioned to be under a target objective lens of the linear array optical detection system, wherein the multiplying power of the target objective lens is larger than that of a single multiplying power objective lens; and controlling a color camera in the area array optical detection system to scan the image of the target detection area.

That is, when a defect is detected in an image scanned by the linear array optical detection system, the area where the defect is located is moved under the linear array optical detection system, the defect area is scanned again by using a target objective lens in the linear array optical detection system (the magnification of the target objective lens is larger than that of a single-magnification objective lens in the linear array optical detection system), and then a color camera in the linear array optical detection system is controlled to scan the image of the target detection area so as to obtain a color detail image of the defect.

In another embodiment, the control unit is further configured to:

when a defect is detected in a black-and-white image scanned in an area array optical detection system, controlling the color camera in the area array optical detection system to perform image scanning on a target detection area where the defect is located;

that is, in the scanning process by using the area array optical detection system, if a defect is detected in the black-and-white image, the color camera is controlled to perform image scanning on the target detection area where the defect is located, so as to obtain a color image of the defect.

Further, in order to improve the detection efficiency of the detection object, the control unit may further control the black-and-white camera and the color camera in the area array optical detection system to synchronously scan the image of the detection area, so as to synchronously acquire the black-and-white image and the color image of the detection area, so as to improve the efficiency of acquiring the defective color image.

Based on the embodiment described in fig. 1, the following is a detailed description of the first light source 101 in the area array optical detection system 10 and the second light source 201 in the linear array optical detection system 20:

as an alternative embodiment, the first light source 101 may be a first annular light source, which provides a light beam for irradiating the detection area in the detection object at a preset angle, and the second light source 201 may be a second annular light source, which provides a light beam for irradiating the detection area in the detection object at a preset angle, where the first plane of the first annular light source and the second plane of the second annular light source are both parallel to the plane of the detection object, and as shown in fig. 1, when the first light source 101 is the first annular light source and the second light source 201 is the second annular light source, the detection signal of the detection area is mainly a scattering signal of the detection area.

Based on the actual detection scene, the first light source 101 may also be a first bright field light source for providing vertical illumination of the detection area in the detection object, and the second light source 201 may also be a second bright field light source for providing vertical illumination of the detection area in the detection object, where both the first bright field light source and the second bright field light source may be point light sources or surface light sources, and the specific limitation is not restricted herein.

When the first light source 101 is a first bright field light source and the second light source 201 is a second bright field light source, the provided light beam perpendicularly irradiating the detection area returns to the objective lens, so that when the first light source 101 is a first bright field light source and the second light source 201 is a second bright field light source, the detection signal is mainly a reflection signal of the detection area.

For ease of understanding, fig. 4 shows a schematic optical path of the optical detection system when the first light source 101 is a first bright field light source and the second light source 201 is a second bright field light source.

As another alternative embodiment, the area array optical detection system 10 may be further provided with a first annular light source 1011 and a first bright field light source 1012 at the same time, and the linear array optical detection system 20 may be also provided with a second annular light source 2011 and a second bright field light source 2012 at the same time, so as to be used for simultaneously illuminating the detection area of the detection object in some scenes, and since the defects of the detection object are different, possible defects may be imaged by reflected signals, and some defects need to be imaged by scattered signals, fig. 5 provides a schematic diagram of the area array optical detection system including the first annular light source 1011 and the first bright field light source 1012 at the same time, and the linear array optical detection system including the first annular light source 2011 and the second bright field light source 2012 at the same time.

Specifically, in the area array optical detection system, a first plane in which the first annular light source 1011 is located is parallel to a plane in which the detection object is located, and the first bright field light source 1012 is disposed in a third plane perpendicular to the first plane, and the first bright field light source 1012 is disposed coaxially with an optical axis of the first annular light source 1011 through a mirror and a beam splitter, so as to be used for providing a light beam for vertically irradiating the detection area of the detection object;

in the linear array optical detection system, a second plane in which the second annular light source 2011 is located is also parallel to a plane in which the detection object is located, the second bright field light source 2012 is disposed in a fourth plane perpendicular to the second plane, and the second bright field light source 2012 is disposed coaxially with an optical axis of the second annular light source 2011 through a reflector and a spectroscope, so as to be used for providing a light beam for perpendicularly irradiating the detection area of the detection object.

The detection principle of the optical detection system in the embodiment of fig. 5 is described below:

when the area array optical detection system 10 works, the first annular light source 1011 and the first bright field light source 1012 can be turned on at the same time, so that the first annular light source 1011 and the first bright field light source 1012 irradiate the detection area of the detection object at the same time, and then the frame-by-frame image scanning is performed on the detection area through the area array detection camera 103, because some defects in the detection area can be imaged by the scattered signals irradiated by the first annular light source 1011 and some defects can be imaged by the reflected signals irradiated by the first bright field light source 1012, when the first annular light source 1011 and the first bright field light source 1012 are turned on at the same time, the efficiency of detecting different defects in the detection area can be improved.

Similarly, when the linear array optical detection system 20 works, the second annular light source 2011 and the second bright field light source 2012 can be turned on simultaneously, so that the second annular light source 2011 and the second bright field light source 2012 irradiate the detection area of the detection object simultaneously, and then the progressive image scanning is performed on the detection area through the linear array detection camera 203, because some defects in the detection area can be imaged by the scattered signals irradiated by the second annular light source 2011 and some defects can be imaged by the reflected signals irradiated by the second bright field light source 2012, when the second annular light source 2011 and the second bright field light source 2012 are turned on simultaneously, the efficiency of detecting different defects in the detection area can be improved.

Based on the optical detection system described in fig. 5, in order to obtain a clear scan image when the detected object is warped, an autofocus sensor may be further disposed in the area array optical detection system 10 and the linear array optical detection system 20 described in fig. 5, so as to implement autofocus on different planes of the detection area when the detected object is warped.

For ease of understanding, fig. 6 presents a schematic view of an optical detection system provided with an autofocus sensor.

Specifically, in the optical system shown in fig. 6, a first autofocus sensor 105 is disposed in the area array optical detection system 10, and a second autofocus sensor 204 is disposed in the linear array optical detection system 20, where the first autofocus sensor 105 is disposed in a plane where the first bright field light source 1012 is located through a beam splitter and a mirror, in order to reduce the volume of the optical path, the first autofocus sensor 105 is disposed in a direction perpendicular to the optical axis of the first bright field light source 1012, and when the plane where the detection object is located is warped, the first autofocus sensor 105 is configured to change the distance between the detection area of the detection object and the plurality of objective lenses with different magnifications, so as to implement clear imaging of the plurality of objective lenses with different magnifications and the detection area on different planes by the area array detection camera.

Similarly, the second autofocus sensor 204 is also disposed in the plane where the second bright field light source 2012 is located by a beam splitter and/or a reflecting mirror, in order to reduce the volume of the optical path, the second autofocus sensor 204 is disposed in a direction perpendicular to the optical axis of the second bright field light source 2012, and when the plane where the detection object is located is warped, the second autofocus sensor 204 is configured to change the distance between the detection area of the detection object and the single-magnification objective lens, so as to implement clear imaging of the single-magnification objective lens and the linear array detection camera on the detection area on different planes.

According to the optical detection system, when warpage occurs in the detection area of the detection object, automatic focusing on planes of different detection areas in the detection object can be achieved, and therefore accuracy of defect detection in the warpage detection object is improved.

Based on the optical detection system shown in fig. 6, when the first bright field light source 1012 or the second bright field light source 2012 is used to illuminate the detection region of the detection object, because the reflected signal is used for imaging, there is a certain requirement on the brightness of the light source, for example, the brightness of the light source cannot be lower than X candela per square meter, so in the optical detection system of the embodiment shown in fig. 6, a light intensity monitor may be further disposed to monitor the light intensity of the first bright field light source 1012 or the second bright field light source 2012.

For ease of understanding, fig. 7 presents a schematic view of an optical detection system provided with a light intensity monitor.

Specifically, in the optical detection system shown in fig. 7, a first light intensity monitor 106 is disposed in the area array optical detection system 10, and a second light intensity monitor 205 is disposed in the line array optical detection system 20, where the first light intensity monitor 106 is disposed in a plane where the first bright field light source 1012 is located through a mirror and a beam splitter, and in order to reduce the optical path volume, the first light intensity monitor 106 is disposed in a direction perpendicular to an optical axis of the first bright field light source for monitoring the light intensity of the first bright field light source 1012 to ensure that the light intensity of the first bright field light source is within a preset light intensity range.

Similarly, the second light intensity monitor 205 is disposed in the plane of the second bright field light source 2012 by a reflector and a beam splitter, and in order to reduce the optical path volume, the second light intensity monitor 205 is disposed in a direction perpendicular to the optical axis of the second bright field light source for monitoring the light intensity of the second bright field light source 2012, so as to ensure that the light intensity of the second bright field light source is also within a preset light intensity range.

The embodiment of the application can monitor the light intensity of the first bright field light source and the second bright field light source so as to ensure that the light intensity of the first bright field light source and the second bright field light source is within a preset light intensity range, thereby further improving the accuracy of defect detection in a detection area under the irradiation of the bright field light source.

Based on the embodiment described in fig. 7, since different detection objects are relatively sensitive to wavelengths of different wavebands, in this embodiment of the present application, optical filters may be further disposed along the direction of the light beam of the first bright field light source 1012 and along the direction of the light beam of the second bright field light source 2012, respectively, so as to screen wavelengths of a preset waveband from the first bright field light source 1012 and the second bright field light source 2012, so as to vertically irradiate the detection area of the detection object through the wavelengths of the preset waveband, where the preset waveband depends on the material of the detection object.

In order to provide a plurality of optical filters, in this embodiment of the present application, filter wheels are respectively disposed along the direction of the light beam of the first bright field light source 1012 and along the direction of the light beam of the second bright field light source 2012, so as to be used for placing different optical filters, where each optical filter is used for screening wavelengths in a certain band.

Further, in order to screen out the wavelength sensitive to the material of the detection object from the scattered signals of the first annular light source 1011 and the second annular light source 1012, the embodiment of the present application further sets an optical filter 108 on the optical path between the objective lens of the area array optical detection system and the area array detection camera, and sets an optical filter 207 on the optical path between the objective lens of the area array optical detection system and the area array detection camera, so as to screen out the scattered signal relatively sensitive to the material of the detection object from the scattered signals of the detection area.

For ease of understanding, fig. 8 shows a schematic diagram of an optical detection system in which a filter wheel is provided on the optical path of the bright field light source and a filter is provided on the optical path of the annular light source.

In the embodiment of the application, the optical filters are respectively arranged on the optical path of the bright field light source and the optical path of the annular light source, so that the preset wavelength sensitive to the material of the detection object is screened out, and the accuracy of defect detection in the detection objects of different materials is improved.

Based on the optical detection system shown in fig. 8, when the first bright field light source 1012 irradiates the detection area vertically, because the area array detection camera in the area array optical detection system 10 scans the image frame by frame, in order to match the high-brightness LED light source with extremely short exposure time during frame by frame scanning, the first bright field light source 1012 is preferably a stroboscopic xenon lamp, and the second bright field light source 2012 is preferably an LED normally-bright light source.

It is easy to understand that, when the area array detection camera scans the detection area frame by frame, in order to increase the number of images scanned in a unit time, the scanning time of a single image needs to be reduced, and in order to reduce the scanning time of a single image, the moving speed of the area array detection camera opposite to the detection object needs to be increased, and the acquisition speed of the area array detection camera needs to be increased.

In order not to affect the detection effect, the smear length of the image cannot be larger than the resolution precision of the image, namely, the control is performed:

the product of the exposure time of the camera and the moving speed of the detection object in the scanning direction is not more than the preset image resolution precision (such as 1 pixel).

Further, in order to ensure that the strobe xenon lamp just lights, the area array detection camera can scan a single frame image, so the embodiment of the application also needs the control unit to control:

the product of the stroboscopic period of the stroboscopic xenon lamp and the moving speed of the detection object in the scanning direction is not larger than the height of a single frame image scanned by the area array detection camera along the scanning direction.

According to the method and the device, the stroboscopic xenon lamp is used as the first bright field light source in the area array detection camera, so that the requirement of the area array detection camera on light intensity in extremely short exposure time is guaranteed, the product of the exposure time of the camera and the movement speed of a detection object in the scanning direction is further controlled to be not more than the preset image resolution precision, the resolution of a single-frame scanning image is further guaranteed, and the accuracy of defect identification in a detection area is improved.

Based on the optical detection system in the embodiment of fig. 1 to 8, experiments prove that when the detection object is a COMS image sensor, the preset angles of the first annular light source in the area array optical detection system and the second annular light source in the linear array optical detection system are 30 to 60 degrees, so that the accuracy of defect detection in the COMS image sensor can be improved.

The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (11)

1. An optical detection system, comprising:

the area array optical detection system comprises a first light source, a plurality of objective lenses with different multiplying powers and an area array detection camera, wherein the first light source is used for providing light beams for irradiating a detection object at a preset angle, the plurality of objective lenses with different multiplying powers are used for imaging a detection area of the detection object with different multiplying powers, and the area array detection camera is used for scanning the detection area frame by frame;

the linear array optical detection system comprises a second light source, a single-magnification objective lens and a linear array detection camera, wherein the second light source is used for providing a light beam for irradiating a detection object at a preset angle, the single-magnification objective lens is used for carrying out single-magnification imaging on a detection area of the detection object, and the linear array detection camera is used for carrying out progressive image scanning on the detection area;

The area array optical detection system and the linear array optical detection system are matched with each other to realize frame-by-frame image scanning and line-by-line image scanning of the detection area and detect defects of the frame-by-frame scanned image and the line-by-line scanned image.

2. The optical detection system according to claim 1, wherein the area array detection camera is a black-and-white camera, and the area array optical detection system further comprises a color camera disposed in a direction parallel to the black-and-white camera via a spectroscope and a mirror.

3. The optical detection system of claim 1, wherein the first light source comprises a first annular light source and the second light source comprises a second annular light source, and wherein a first plane in which the first annular light source is located and a second plane in which the second annular light source is located are both parallel to a plane in which the detection object is located;

the area array optical detection system further comprises a third light source, wherein the third light source comprises a first bright field light source, the first bright field light source is arranged in a third plane perpendicular to the first plane, the first bright field light source is coaxially arranged with the optical axis of the first annular light source through a reflector and a spectroscope, and the first bright field light source is used for providing a light beam for vertically irradiating a detection area in the detection object;

The linear array optical detection system further comprises a fourth light source, the fourth light source comprises a second bright field light source, the second bright field light source is arranged in a fourth plane perpendicular to the second plane, the second bright field light source is coaxially arranged with the optical axis of the second annular light source through a reflector and a spectroscope, and the second bright field light source is used for providing light beams for perpendicularly irradiating a detection area in the detection object.

4. The optical detection system of claim 1, wherein the first light source comprises a first bright field light source that vertically irradiates the detection area, the second light source comprises a second bright field light source that vertically irradiates the detection area, and the first bright field light source and the second bright field light source both provide light beams that vertically irradiate the detection area through a mirror and a beam splitter, respectively;

the area array optical detection system further comprises a third light source, wherein the third light source comprises a first annular light source, a first plane where the first annular light source is located is parallel to a plane where the detection object is located, the first plane is perpendicular to the plane where the first bright field light source is located, and an optical axis of the first annular light source and a light beam of the first bright field light source irradiating the detection area are coaxially arranged;

The linear array optical detection system further comprises a fourth light source, the fourth light source comprises a second annular light source, a second plane where the second annular light source is located is parallel to a plane where the detection object is located, the second plane is perpendicular to the plane where the second bright field light source is located, and an optical axis of the second annular light source and a light beam of the second bright field light source irradiating the detection area are coaxially arranged.

5. The optical detection system of claim 3 or 4, wherein the area array optical detection system further comprises a first autofocus sensor, and the line array optical detection system further comprises a second autofocus sensor;

the first automatic focusing sensor is arranged in a plane where the first bright field light source is located through a spectroscope and a reflecting mirror and is perpendicular to the optical axis of the first bright field light source, and the first automatic focusing sensor is used for changing the distance between the detection area of the detection object and the plurality of objective lenses with different multiplying powers so as to realize clear imaging of the plurality of objective lenses with different multiplying powers and the area array detection camera on the detection area in the detection object;

the second automatic focusing sensor is arranged in a plane where the second bright field light source is located through a spectroscope and a reflecting mirror and is perpendicular to the optical axis of the second bright field light source, and the second automatic focusing sensor is used for changing the distance between different detection areas of the detection object and the single-magnification objective lens so as to realize clear imaging of the single-magnification objective lens and the linear array detection camera on different detection areas in the detection object.

6. The optical detection system according to claim 3 or 4, further comprising a first light intensity monitor, wherein the first light intensity monitor is disposed in a plane where the first bright field light source is located and in a direction perpendicular to an optical axis of the first bright field light source by a reflector and a spectroscope, and is configured to monitor a light intensity of the first bright field light source to ensure that the light intensity of the first bright field light source is within a preset light intensity range;

the linear array optical detection system further comprises a second light intensity monitor, wherein the second light intensity monitor is arranged in a plane where the second bright field light source is located through a reflector and a spectroscope and is perpendicular to the optical axis of the second bright field light source, so that the light intensity of the second bright field light source is monitored, and the light intensity of the second bright field light source is ensured to be within a preset light intensity range.

7. The optical detection system according to claim 3 or 4, further comprising a first filter wheel disposed along a direction of a light beam emitted by the first bright field light source, wherein a plurality of filters are disposed in the first filter wheel to screen light waves of a preset wavelength band from the first bright field light source;

The linear array optical detection system further comprises a second filter wheel arranged along the direction of the light beam emitted by the second bright field light source, wherein a plurality of optical filters are arranged in the second filter wheel so as to screen light waves with preset wave bands from the second bright field light source.

8. The optical detection system according to claim 3 or 4, further comprising a first optical filter provided between the plurality of objective lenses of different magnifications and the area array detection camera in the optical axis direction of the first annular light source for screening out a target wavelength sensitive to the detection object;

the linear array optical detection system further comprises a second optical filter arranged between the Shan Beilv objective lens and the linear array detection camera along the optical axis direction of the second annular light source, and the second optical filter is used for screening out target wavelengths sensitive to the detection object.

9. The optical detection system of claim 1, wherein the second light source comprises a strobe xenon lamp.

10. The optical detection system according to claim 1, further comprising an objective lens turret, wherein the plurality of objective lenses of different magnifications are mounted on the objective lens turret, and the objective lens turret switches the objective lenses of different magnifications when moving along a circle so that the objective lens images a detection area of the detection object of different magnifications;

Or,

the area array optical detection system further comprises a linear movement module, wherein a plurality of objective lenses with different multiplying powers are installed on the linear movement module, and the objective lenses with different multiplying powers are switched when the linear movement module moves along a straight line, so that the objective lenses image the detection area of the detection object with different multiplying powers.

11. The optical detection system according to claim 3 or 4, wherein when the detection object is a COMS image sensor, the incidence angles of the first annular light source and the second annular light source include 30 to 60 degrees.