JP5362368B2 - Appearance inspection apparatus and appearance inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and method for inspection of external appearance that shorten an imaging distance and a time tact. <P>SOLUTION: Arbitrary telecentric lenses 18c, 18d among a plurality of telecentric lenses where the width of whole pixels is larger than a scanning line width are arranged so as to allow optical axes to be vertical with respect to the surface of a movement stage. The other telecentric lenses 18a, 18b are arranged so as to allow the optical axes to be in parallel with the surface of the movement stage. Thus, a scanning line with respect to a workpiece on the movement stage is closely arranged in a scanning direction, thereby shortening the visual field intervals of line sensors 13. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an appearance inspection apparatus and an appearance inspection method capable of optically inspecting the appearance of a fine component, and more particularly to an appearance inspection apparatus and an appearance inspection method capable of reducing process work time (tact time).

  In recent years, electronic components have been miniaturized. For example, an LSI pad for connecting an LSI lead terminal to a substrate has a cubic shape with a width of 270 μm, a depth of 190 μm, and a height of 45 μm. It is necessary to perform an appearance inspection with an accuracy of 10 μm or more to determine whether there is a shape abnormality.

  As shown in FIG. 7, in the conventional visual inspection apparatus, a plurality of line sensors 13 are arranged on a base 11 formed in six locations with 2000 LSI pads 10 as a group, and these line sensors 13 are arranged in the direction of arrow A. It is configured to perform an optical inspection by scanning.

  As shown in FIG. 6, the line sensor 13 optically scans the scanning line 91 in the arrow A direction via the telecentric lens 18 having the coaxial illumination 17. This telecentric lens is a lens in which the chief rays are arranged so as to pass through the focal point, so that the chief rays are parallel to the optical axis (lens whose angle of view is 0 °). Measurement error occurs because the image size changes when moving in the axial direction, but the image size does not change even if the position of the object moves, and image distortion due to parallax occurs And a characteristic that a stable image can be taken in a flat plate-like workpiece by the combined use with the coaxial illumination 17.

  Incidentally, as a document describing an appearance inspection apparatus capable of optically inspecting the appearance of the above-mentioned fine parts, the following Patent Document 1 can be cited, and this Patent Document 1 includes a flat inspection object. A moving means for moving along the direction A, a linear illumination means spaced in parallel to the moving plane of the inspection object and arranged along a direction intersecting the moving direction A of the inspection object; Incident direction setting means for causing light emitted from the illumination means to enter obliquely forward, obliquely backward, or both directions in the moving direction A of the inspection object, and a line sensor for imaging the light reflected by the inspection object Although a technology that enables high-accuracy inspection without being affected by the mounting direction of components by using a configuration including a camera is described, a relatively large-diameter telecentric lens is used. It is not described inspection apparatus.

  Japanese Patent Laid-Open No. 11-160035

  In the appearance inspection apparatus using the telecentric lens described above, the telecentric lens 18 has a lens tube size twice that of the scanning field width (scanning line length) L04 (for example, the entire field width L04 = 20 mm). Therefore, in order to scan the base 11 on which the LSI pad group shown in FIG. 7 is arranged 3 × 3, the cylindrical width of the telecentric lens 18 is shown as a circle. Thus, the base 11 must be moved 85.4 mm relative to the plurality of telecentric lenses 18, so that the visual field interval of one line sensor becomes redundant, and the imaging distance and time tact There was a problem that would be longer.

  An object of the present invention is to provide an appearance inspection apparatus and an appearance inspection method capable of shortening an imaging distance and a time tact by shortening a visual field interval of a line sensor.

In order to achieve the above object, the present invention comprises a plurality of telecentric lenses having a total pixel width larger than the scanning line width on a plate-like object to be inspected, and is adjacent in a direction perpendicular to the direction of object movement. An appearance inspection apparatus for imaging and inspecting a fourth scanning area from a first scanning area on an object to be inspected ,
A plate-like moving stage that carries the plate-like object to be inspected and moves in the XY direction;
A plurality of parallel arranged telecentric lenses arranged in line symmetry with respect to the perpendicular direction so that the optical axis is parallel to the surface of the moving stage with respect to the surface of the moving stage;
A plurality of reflecting mirrors that receive and reflect the scanning light emitted from the plurality of parallel arranged telecentric lenses;
A plurality of parallel-arranged line sensors that make incident scanning light reflected by the plurality of reflecting mirrors and photoelectrically convert image signals;
A plurality of vertically arranged telecentric lenses arranged in line symmetry with respect to the perpendicular direction so that the optical axis is perpendicular to the surface of the moving stage;
A plurality of vertically arranged line sensors that enter scanning light emitted from the plurality of vertically arranged telecentric lenses and perform photoelectric conversion on image signals;
An image processing unit that processes an image signal of an object to be inspected with an image signal photoelectrically converted by the plurality of vertical arrangement and parallel arrangement line sensors as an input;
The parallel-arranged telecentric lens, the reflector, and the parallel-arranged line sensor form a first optical system that scans the first scanning area and a second optical system that scans a second scanning area adjacent to the first scanning area. And
The vertically arranged telecentric lens, the reflecting mirror, and the vertically arranged line sensor form a third optical system that scans the third scanning area and a fourth optical system that scans the fourth area adjacent to the third area. the second optical system and the fourth optical system is the perpendicular direction to the same the upper line after scanning the first optical system and the third optical system is the perpendicular direction that you scan on the same line a first Features.

According to the second aspect of the present invention, the parallel inspection optical system and the vertical arrangement optical system are alternately arranged in a direction perpendicular to the moving direction of the inspection object .

Furthermore, the present invention provides a flat plate-like moving stage that mounts a plate-like object to be inspected and moves in the XY direction, and an optical axis that is parallel to the surface of the moving stage with respect to the surface of the moving stage. A plurality of parallel arranged telecentric lenses having a total pixel width larger than a scanning line width arranged in line symmetry with respect to the perpendicular direction, and a plurality of scanning lights incident from and reflected from the plurality of parallel arranged telecentric lenses Reflector, a plurality of parallel line sensors that photoelectrically convert image signals by entering the scanning light reflected by the plurality of reflectors, and an optical axis perpendicular to the surface of the moving stage A plurality of vertically arranged telecentric lenses having a total pixel width larger than a scanning line width arranged in line symmetry with respect to the perpendicular direction, and scanning emitted from the plurality of vertically arranged telecentric lenses Image processing for processing an image signal of an object to be inspected by inputting a plurality of vertical arrangement line sensors that perform photoelectric conversion on an image signal by inputting the image signal, and image signals photoelectrically converted by the plurality of vertical arrangement and parallel arrangement line sensors And a visual inspection method for imaging and inspecting a first scanning region to a fourth scanning region on an inspection object adjacent in a direction perpendicular to the inspection object movement direction .
The parallel-arranged telecentric lens, the reflecting mirror, and the parallel-arranged line sensor form a first optical system that scans the first scanning region and a second optical system that scans a second scanning region adjacent to the first scanning region. The vertically arranged telecentric lens and the vertically arranged line sensor form a third optical system that scans the third scanning region and a fourth optical system that scans a fourth region adjacent to the third region;
After the second optical system and the fourth optical system scan the same line in the perpendicular direction, the first optical system and the third optical system operate so as to scan the same line in the perpendicular direction . Three features.

According to a fourth aspect of the present invention, in the visual inspection method, the parallel arrangement optical system and the vertical arrangement optical system are alternately arranged in a direction perpendicular to the moving direction of the inspection object .

  In the visual inspection apparatus and visual inspection method according to the present invention, an optical axis of any telecentric lens out of a plurality of telecentric lenses having a total pixel width larger than the scanning line width is perpendicular to the surface of the moving stage. By arranging the other telecentric lens so that the optical axis is parallel to the surface of the moving stage with respect to the surface of the moving stage, the scanning line for the object to be inspected on the moving stage is set in the scanning direction. They can be arranged closely, thereby shortening the imaging distance and time tact by shortening the visual field interval of the line sensor.

The figure which shows the whole structure of the external appearance inspection apparatus by one Embodiment of this invention. The figure which shows the whole structure arrangement | positioning of the external appearance inspection apparatus by this embodiment. The figure for demonstrating the scanning of the external appearance inspection apparatus by this embodiment. The figure which shows the optical system of the external appearance inspection apparatus by this embodiment. The figure which shows the structure part of the external appearance inspection apparatus by this embodiment. The figure for demonstrating a telecentric lens. The figure for demonstrating the scanning of the external appearance inspection apparatus by a prior art.

Hereinafter, an appearance inspection apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the overall configuration of the appearance inspection apparatus according to the present embodiment is divided into four line sensors 13 that scan the LSI pad scanning area 90 and light on two scanning lines in the line sensor 13. And a personal computer 50 that displays an analysis result input by the image processing unit 30 and an analysis result input by the image processing unit 30.

  As shown in FIG. 2, the overall configuration of the appearance inspection apparatus includes a first optical system for optically scanning the first scanning area and a second for optically scanning the second scanning area. The optical system includes a third optical system for optically scanning the third scanning region, and a fourth optical system for optically scanning the fourth scanning region.

  The first optical system irradiates light irradiated from the coaxial illumination 17a onto the first irradiation region, receives the reflected light, and polarizes the light parallel to the lens optical axis and emits the first centric lens 18a. A reflection mirror 16a that enters and reflects the reflected light from the irradiated region and enters the telecentric lens 18a, and a line sensor 13a that receives the scanning light emitted from the telecentric lens 18a.

  The second school system irradiates the light irradiated from the coaxial illumination 17b to the second irradiation region, receives the reflected light, polarizes it parallel to the lens optical axis, and emits the telecentric lens 18b. A reflection mirror 16b that enters and reflects the reflected light from the irradiation region and enters the telecentric lens 18b, and a line sensor 13b that receives the scanning light reflected from the reflection mirror 16b.

  The third optical system irradiates light irradiated from the coaxial illumination 17c to the third irradiation region, receives the reflected light, and polarizes the light in parallel with the lens optical axis and emits the telecentric lens 18c. And a line sensor 13c that receives light emitted from the lens 18c.

  The fourth optical system irradiates light irradiated from the coaxial illumination 17d to the fourth irradiation region, receives the reflected light, and polarizes the light parallel to the lens optical axis and emits it, and the telecentric lens 18d. The line sensor 13d receives light emitted from the lens 18d.

  In particular, in the optical system according to the present embodiment, the first optical system that scans the first scanning region and the second optical system that scans the second scanning region adjacent to the first scanning region are parallel to the scanning region surface. And a third optical system that scans the third scanning region and a fourth optical system that scans a fourth region adjacent to the third region are arranged in a direction perpendicular to the scanning region plane. It is configured.

  As shown in FIG. 4A, the first and second optical systems are arranged to face each other so that the scanning areas do not overlap with the moving direction of the inspection object (base 11). The reflected light is polarized 90 degrees by the reflecting mirrors 16a and 16b, the respective lights are incident on the telecentric lenses 18a and 18b, and the scanning lights emitted from the telecentric lenses 18a and 18b are incident on the line sensors 13a and 13b. Adjacent first and second regions can be optically scanned. Note that the scanning area may be overlapped because it can be deleted by an image processing section described later.

  As shown in FIG. 4B, the third and fourth optical systems are arranged vertically so that the scanning regions do not overlap with the moving direction of the inspection object (base 11), and are reflected from the inspection object. Light is incident on the telecentric lenses 18c and 18d, and the line sensors 13c and 13d are incident on the light emitted from the telecentric lenses 18c and 18d, so that the adjacent third and fourth regions can be optically scanned. . Note that the scanning area may be overlapped because it can be deleted by an image processing section described later.

  As shown in FIG. 5, the components of the entire appearance inspection apparatus according to the present embodiment include a first optical system unit 20a, a line sensor 13a for inputting reflected light emitted from the first optical system unit 20a, and the line. An image processing unit 30a that inputs image data converted by an electrical signal by photoelectric conversion by the sensor 13a and extracts an image of an LSI pad, a second optical system unit 20b, and a scan emitted from the first optical system unit 20b A line sensor 13b for inputting light, an image processing unit 30b for inputting image data converted by an electrical signal by photoelectric conversion by the line sensor 13b, extracting an image of the LSI pad, and determining a shape abnormality; The determination results output from the third and fourth optical systems / line sensors / image processing units, the image processing unit 30a, and the like and the image of the abnormal shape portion are transmitted via the LAN 40. A personal computer 50 that inputs via the AN interface 51 and displays an LSI pad shape abnormality, and a motor controller 52 of the personal computer 50 controls the motor drivers 54 and 55 to move the object under inspection (base 11) in the X and Y directions. And an XY stage that moves to the position.

  As shown in FIG. 3, the visual inspection apparatus according to the present embodiment configured as described above has an axial direction of the telecentric lenses 18a and 18b of the inspection object when viewed from the upper surface side of the inspection object (base 11). By arranging the telecentric lenses 18c and 18d perpendicular to the surface of the object to be inspected, the field interval is halved (42.7 mm) compared to the conventional case shown in FIG. As a result, the imaging distance and the time tact can be shortened.

That is, the visual inspection apparatus according to the present embodiment has a plurality of telecentric lenses having a structure in which the total pixel width L02 is larger than the visual field width L04 on the object to be inspected, and the optical axis is perpendicular and parallel to the base surface. By arranging in this way, it is possible to arrange the scanning lines of the line sensor more closely than in the prior art, thereby shortening the imaging distance and time tact.

In this embodiment, an example in which two telecentric lenses are alternately arranged in the same arrangement has been described. However, the present invention is not limited to this, and for example, telecentric lenses arranged vertically and in parallel are arranged alternately. Other arrangements may be made.

13, 13a to 13d: line sensor, 16, 16a, 16b: reflecting mirror,
17, 17a to 17d: coaxial illumination, 18, 18a to 18d: telecentric lens,
20a, 20b: optical system unit, 30, 30a, 30b: image processing unit,
50: Personal computer 51: LAN interface
52: Motor controller, 54: Motor driver, 90: Pad scanning area.

Claims (4)

A first scanning region on a moving object to be inspected that includes a plurality of telecentric lenses having a total pixel width larger than a scanning line width on a plate-shaped object to be inspected and is adjacent to the direction of the object to be inspected perpendicularly A visual inspection apparatus for imaging and inspecting the fourth scanning region ,
A plate-like moving stage that carries the plate-like object to be inspected and moves in the XY direction;
A plurality of parallel arranged telecentric lenses arranged in line symmetry with respect to the perpendicular direction so that the optical axis is parallel to the surface of the moving stage with respect to the surface of the moving stage;
A plurality of reflecting mirrors that receive and reflect the scanning light emitted from the plurality of parallel arranged telecentric lenses;
A plurality of parallel-arranged line sensors that make incident scanning light reflected by the plurality of reflecting mirrors and photoelectrically convert image signals;
A plurality of vertically arranged telecentric lenses arranged in line symmetry with respect to the perpendicular direction so that the optical axis is perpendicular to the surface of the moving stage;
A plurality of vertically arranged line sensors that enter scanning light emitted from the plurality of vertically arranged telecentric lenses and perform photoelectric conversion on image signals;
An image processing unit that processes an image signal of an object to be inspected with an image signal photoelectrically converted by the plurality of vertical arrangement and parallel arrangement line sensors as an input;

The parallel-arranged telecentric lens, the reflector, and the parallel-arranged line sensor form a first optical system that scans the first scanning area and a second optical system that scans a second scanning area adjacent to the first scanning area. The vertical arrangement telecentric lens, the reflecting mirror, and the vertical arrangement line sensor include a third optical system that scans the third scanning area and a fourth optical system that scans the fourth area adjacent to the third area. Forming,
An appearance inspection apparatus in which the first optical system and the third optical system scan the same line in the perpendicular direction after the second optical system and the fourth optical system scan the same line in the perpendicular direction . The appearance inspection apparatus according to claim 1, wherein the parallel arrangement optical system and the vertical arrangement optical system are alternately arranged in a direction perpendicular to the moving direction of the inspection object. A flat plate-like moving stage that mounts a plate-like object to be inspected and moves in the XY directions, and the perpendicular direction so that the optical axis is parallel to the surface of the moving stage with respect to the surface of the moving stage A plurality of parallel arranged telecentric lenses having a total pixel width larger than a scanning line width arranged in line symmetry; a plurality of reflecting mirrors that receive and reflect scanning light emitted from the plurality of parallel arranged telecentric lenses; A plurality of parallel-arranged line sensors that photoelectrically convert the image signal by entering the emitted scanning light reflected by the reflecting mirror, and the perpendicular direction so that the optical axis is perpendicular to the surface of the moving stage A plurality of vertically arranged telecentric lenses having a total pixel width larger than the scanning line width arranged symmetrically and scanning light emitted from the plurality of vertically arranged telecentric lenses. A plurality of vertical arrangement line sensors that perform photoelectric conversion, and an image processing unit that processes image signals of an object to be inspected by inputting image signals photoelectrically converted by the plurality of vertical arrangement and parallel arrangement line sensors. A visual inspection method for imaging and inspecting a fourth scanning region from a first scanning region on an object movement adjacent in a direction perpendicular to the inspection object movement direction using an inspection device ,
The parallel-arranged telecentric lens, the reflecting mirror, and the parallel-arranged line sensor form a first optical system that scans the first scanning region and a second optical system that scans a second scanning region adjacent to the first scanning region. The vertically arranged telecentric lens and the vertically arranged line sensor form a third optical system that scans the third scanning region and a fourth optical system that scans a fourth region adjacent to the third region;
An appearance inspection method in which the first optical system and the third optical system operate so as to scan the same line in the perpendicular direction after the second optical system and the fourth optical system scan the same line in the perpendicular direction. . 4. The appearance inspection method according to claim 3, wherein the parallel arrangement optical system and the vertical arrangement optical system are alternately arranged in a direction perpendicular to the moving direction of the inspection object .

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