JP2005337957A - Substrate inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate inspection device capable of clearly imaging the pattern on a substrate. <P>SOLUTION: An imaging head 10 is equipped with a CCD line sensor 20, six first illumination means 30 and a pair of second illumination means 40. The second illumination means 40 are arranged on both sides of the LED arranging direction in the first illumination means 30 so that the irradiation angle of the lights emitted from the second illumination means 40 to the surface of the substrate when the lights emitted from the second illumination means 40 are projected on a reference plane abcd is different from the irradiation angle to the surface of the substrate of the lights emitted from the first illumination means 30 when the lights emitted from the first illumination means 30 are projected on the reference plane abcd. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a substrate inspection apparatus for determining the quality of a pattern printed on a substrate by analyzing an image obtained by imaging a substrate surface.

  Conventionally, as such a substrate inspection apparatus, a CCD line sensor and a linear light source arranged in the CCD array direction in the CCD line sensor are provided, and these CCD line sensor and linear light source are disposed on the substrate surface. A substrate inspection apparatus having a configuration that reads an image of a substrate in a strip shape by moving in the scanning direction is known. Such a conventional substrate inspection apparatus has a problem that accurate density information of an image cannot be obtained when the illuminance distribution for illuminating the area read by the CCD line sensor on the substrate is uneven.

Therefore, as described in Patent Document 1, a plurality of LEDs arranged in the CCD array direction in the CCD line sensor illuminate a region read by the CCD line sensor, and the plurality of LEDs are lenticular lenses. A substrate inspection apparatus has been proposed that can illuminate the substrate via the illuminant to make the illuminance distribution illuminating the area read by the CCD line sensor uniform.
Utility Model Registration No. 2562299

  In the recent substrate where the printed pattern is miniaturized and the substrate surface is processed to make the substrate surface smoother than before by this miniaturization, irregular reflection hardly occurs on the surface of the substrate. Even with a substrate inspection apparatus as described in Document 1, it may be difficult to obtain clear density information due to pattern irregularities in the CCD array direction of the CCD line sensor. As a result, there has been a problem that the pattern printed on the substrate cannot be clearly imaged.

  For example, in the case of a wiring pattern in which a plurality of fine line patterns having a minute width extend in parallel in the direction in which the CCD line sensor scans and moves with respect to the substrate (the direction orthogonal to the arrangement direction of the CCD line sensor) There is a problem that the density of the fine line pattern and the groove between the fine line patterns (the concave part corresponding to the gap between the fine lines) cannot be clearly distinguished. In particular, such a problem is remarkable in a recent miniaturized substrate or a substrate whose substrate surface is smoothed like a mirror surface. Such a problem is considered to be due to a difference in reflection / scattering of illumination light due to the mirror surface of the substrate.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a substrate inspection apparatus capable of clearly imaging a pattern on a substrate.

  According to a first aspect of the present invention, in a substrate inspection apparatus for imaging a substrate surface by a CCD line sensor in which a number of CCDs are arranged, the CCD line sensor is arranged in a direction parallel to the CCD arrangement direction. A first illuminating unit that includes a substantially linear light irradiating unit and irradiates light toward a region imaged by the CCD line sensor on the substrate surface; and both longitudinal sides of the light irradiating unit in the first illuminating unit Of the light emitted from the first illumination means when projected onto a reference plane including a number of CCDs in the CCD line sensor and a region imaged by the CCD line sensor on the substrate surface. Photographed by the CCD line sensor on the substrate surface at an irradiation angle different from the irradiation angle after projection onto the reference plane onto the substrate surface A second illuminating means for irradiating light toward the area, the CCD line sensor, the first illuminating means, and the second illuminating means in a direction perpendicular to the CCD line-up direction in the CCD line sensor, And a moving means for moving the substrate relative to the substrate.

  According to a second aspect of the present invention, in the substrate inspection apparatus according to the first aspect, the first illumination unit includes a plurality of LEDs arranged in a direction parallel to a CCD arrangement direction of the CCD line sensor. It has a configuration.

  According to a third aspect of the present invention, in the substrate inspection apparatus according to the first or second aspect, the second illuminating unit includes a plurality of LEDs in a direction intersecting with the LED arrangement direction in the first illuminating unit. Are arranged in a row.

  According to a fourth aspect of the present invention, in the substrate inspection apparatus according to the third aspect, the light emitted from the LED in the second illuminating unit is between the substrate and the LED in the second illuminating unit. A lenticular lens for making the illuminance distribution on the substrate surface uniform is provided.

  According to a fifth aspect of the present invention, in the substrate inspection apparatus according to any one of the first to fourth aspects, the plurality of LEDs in the second illuminating means are arranged on substantially the same plane as the reference plane. The

  According to a sixth aspect of the present invention, in the substrate inspection apparatus according to any one of the first to fifth aspects, the second illuminating unit is configured to be lit independently of the first illuminating unit. .

  According to the seventh aspect of the present invention, an imaging head having a CCD line sensor in which a plurality of CCDs are arranged is moved relative to the substrate to be inspected, and a wiring pattern on the substrate to be inspected is sequentially imaged and imaged. In the substrate inspection apparatus for inspecting the quality of the pattern based on the image data obtained in this manner, the imaging head includes first illumination means provided substantially parallel to the direction in which the CCD line sensors are arranged, and the first It is characterized by comprising at least a pair of second illuminating means which are disposed separately at both ends of the CCD line sensor separately from the illuminating means and illuminate from both end sides of the CCD line sensor toward the imaging region.

  According to the first aspect of the present invention, since the second illumination unit disposed on both sides in the longitudinal direction of the light irradiation unit in the first illumination unit is provided, the pattern on the substrate can be clearly imaged. It becomes. In particular, by providing the second illuminating means, even in a substrate having a wiring pattern in which a plurality of fine line patterns are arranged in parallel in a direction orthogonal to the direction in which the CCD line sensors are arranged, the fine line pattern and each fine line pattern are not connected. Thus, even a substrate having a relatively smooth mirror surface can be inspected satisfactorily.

  According to the second aspect of the present invention, the first illumination means has a configuration in which a plurality of LEDs are arranged in a direction parallel to the CCD arrangement direction in the CCD line sensor. The region imaged by the sensor can be irradiated with light that is easy to control and highly stable.

  According to the invention described in claim 3, since the second illumination means has a configuration in which a plurality of LEDs are arranged in a direction intersecting with the LED arrangement direction in the first illumination means, the CCD on the substrate surface is provided. The region imaged by the line sensor can be irradiated with light that is easy to control and highly stable.

  According to the invention described in claim 4, since a lenticular lens is provided between the substrate and the LED in the second illumination means, the light emitted from the LED in the second illumination means on the substrate surface. The illuminance distribution can be made uniform.

  According to the invention described in claim 5, since the plurality of LEDs in the second illuminating means are arranged on substantially the same plane as the reference plane, the pattern on the substrate can be imaged more clearly. Become.

  According to the invention described in claim 6, since the second illumination means is configured to be lit independently of the first illumination means, the pattern is clearly defined according to the pattern on the substrate to be imaged. It becomes possible to pick up images.

  According to the seventh aspect of the present invention, the imaging head includes a first illuminating unit provided substantially parallel to the direction in which the CCD line sensors are arranged, and the first illuminating unit separately from both ends of the CCD line sensor. And at least a pair of second illumination means for illuminating from both ends of the CCD line sensor toward the imaging region, it is possible to clearly image the pattern on the substrate. In particular, by providing the second illuminating means, even in a substrate having a wiring pattern in which a plurality of fine line patterns are arranged in parallel in a direction orthogonal to the direction in which the CCD line sensors are arranged, the fine line pattern and each fine line pattern are not connected. Thus, even a substrate having a relatively smooth mirror surface can be inspected satisfactorily.

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

  FIG. 1 is a side sectional view showing an imaging head 10 in a substrate inspection apparatus according to the present invention. FIG. 2 is a sectional view showing the substrate inspection apparatus according to the present invention from the AA direction in FIG.

  The substrate inspection apparatus according to the present invention images a substrate surface by a CCD line sensor 20 in which a large number of CCDs are arranged, and compares the image data of the imaged substrate surface with image data serving as a predetermined reference. It is an apparatus for judging the quality of a pattern printed on a substrate surface. The substrate inspection apparatus includes an imaging head 10 for imaging a substrate and a moving unit 50 (see FIG. 3) that moves the imaging head 10 relative to the substrate. The moving means moves the imaging head 10 in a direction (left and right direction of the drawing in FIG. 1) perpendicular to the CCD line-up direction (perpendicular to the drawing in FIG. 1) of the CCD line sensor 20 relative to the substrate. Move.

  The imaging head 10 includes a hollow casing 11 having a lower surface facing the substrate, an optical system 12 such as a lens that is provided in the casing 11 and collects scanning light incident from an opening on the lower surface, and the casing. 11, a CCD line sensor 20 that receives light collected by the optical system 12, and six first illumination means that irradiate light toward a region imaged by the CCD line sensor 20 on the substrate surface. 30 and a pair of second illumination means 40 for irradiating light toward a region imaged by the CCD line sensor 20 on the substrate surface.

  FIG. 3 is a block diagram showing the main electrical configuration of the substrate inspection apparatus according to the present invention. The board inspection apparatus includes a control unit 60 including a ROM 61 that stores an operation program necessary for controlling the apparatus, a RAM 62 that temporarily stores data and the like during control, and a CPU 63. The control unit 60 is connected to the moving unit 50, the CCD line sensor 20, the first illumination unit 30, and the second illumination unit 40 via the interface 64, and controls these operations. The second illumination means 40 can be turned on independently of the first illumination means 30 under the control of the control unit 60.

  In the substrate inspection apparatus, a plurality of imaging heads 10 may be arranged in a row so that the entire substrate can be imaged with a single movement. You may make it image a shape area | region repeatedly repeatedly. The latter includes a case in which the moving unit 5 is a mechanism that moves the imaging head 10 relatively in the sub-scanning direction in the CCD line direction in the CCD line sensor 20.

  FIG. 4 is an enlarged perspective view showing the first illumination means 30 and the second illumination means 40 described above.

  The first illumination means 30 has a configuration in which a plurality of LEDs 31 are arranged on the first support member 34 in a direction parallel to the CCD arrangement direction of the CCD line sensor 20. Then, the substrate to be inspected is irradiated with light substantially linearly in a direction parallel to the CCD line-up direction in the CCD line sensor 20.

  The first illumination unit 30 includes a lenticular lens 33 between the substrate and the LED 31. The lenticular lens 33 is fixed to the first support member 34 by a pair of column members 36 erected on the first support member 34. By the action of the lenticular lens 33, the illuminance distribution on the substrate surface of the light emitted from the LED 31 can be made uniform. Further, as shown in FIGS. 1 and 2, the first illumination unit 30 includes a linear Fresnel lens 32 between the substrate and the lenticular lens 33. The linear Fresnel lens 32 only needs to be on the irradiation optical axis from the LED 31 to the substrate. In this embodiment, the linear Fresnel lens 32 is bonded and fixed to the lenticular lens 33. By the action of the linear Fresnel lens 32, the light emitted from the LED 31 can be condensed on the area of the substrate surface imaged by the CCD line sensor 20. In FIG. 4, the illustration of the linear Fresnel lens 32 is omitted.

  FIG. 5 is an explanatory diagram schematically showing a positional relationship among the CCD line sensor 20, the first illumination means 30, and the second illumination means 40. 6 shows the light emitted from the first illuminating means 30 and the second illuminating means 40 as the reference plane abcd in FIG. 5 (line segment ad representing the arrangement direction of the CCD line sensor 20 and line representing the imaging region). It is explanatory drawing which shows the irradiation angle of the light at the time of projecting on the plane containing min bc.

  5 and 6, the LEDs 31 arranged in the first illumination unit 30 and the LEDs 41 arranged in the second illumination unit 40 are schematically shown. The direction parallel to the line segment ad is the Y axis, the direction parallel to the line segment ab is the Z axis, and the direction perpendicular to the plane abcd is the X axis.

  The pair of second illumination means 40 are disposed on both sides of the first illumination means 30 in the row direction of the LEDs 31. As shown in FIG. 6, the second illuminating unit 40 irradiates the light emitted from the second illuminating unit 20 onto the reference plane abcd, the irradiation angle of the light on the substrate surface (hereinafter referred to as “irradiation after second projection”). Θ2) is different from an irradiation angle (hereinafter referred to as an “irradiation angle after the first projection”) θ1 when the light emitted from the first illumination unit 30 is projected onto the reference plane abcd. Are arranged as follows. (In this embodiment, θ1 is 0 °, that is, perpendicular to the irradiation surface.) Therefore, a direction in which a plurality of fine thin lines are orthogonal to the direction in which the CCD line sensors 20 are arranged (the paper surface in FIG. 6). Even if the wiring pattern is arranged in parallel in the vertical direction, the fine lines and the grooves between the fine lines can be well illuminated. In particular, even on a substrate that has been subjected to smooth planar processing, it is possible to clearly image a pattern printed on the substrate.

  Further, as shown in FIGS. 4 and 6, the second illumination means 40 has a plurality of LEDs 41 arranged on the second support member 44 in a direction intersecting with the arrangement direction of the LEDs 31 in the first illumination means 30. It has a configuration. In addition, it is preferable that the 2nd illumination means 40 is arrange | positioned so that it may become a uniform light quantity distribution with respect to the imaging region on a board | substrate by the illumination. Moreover, it is preferable that LED41 in the 2nd illumination means 40 is arrange | positioned on substantially the same plane as the reference plane abcd.

  2 and 4, the second illumination unit 40 includes a lenticular lens 43 between the substrate and the LED 41. The lenticular lens 43 is fixed to the second support member 44 via a fixing member (not shown). By the action of the lenticular lens 43, the illuminance distribution on the substrate surface of the light emitted from the LED 41 can be made uniform. Further, as shown in FIG. 2, the second illumination unit 40 includes a linear Fresnel lens 42 between the substrate and the lenticular lens 43. The linear Fresnel lens 42 only needs to be on the irradiation optical axis from the LED 41 to the substrate. In this embodiment, the linear Fresnel lens 42 is bonded and fixed to the lenticular lens 43. By the action of the linear Fresnel lens 42, the light emitted from the LED 41 can be condensed on the area of the substrate surface imaged by the CCD line sensor 20.

  In this embodiment, the reason why the first illumination unit 30 and the second illumination unit 40 irradiate light with the LEDs 31 and 41 is that control is easy and light with high stability can be emitted. . However, it is also possible to use a single linear light source instead of arranging a large number of LEDs 31 and LEDs 41 to form a linear light source.

  When imaging the substrate using the substrate inspection apparatus as described above, the imaging head 10 is moved in parallel with the substrate surface by the moving means 60. At this time, the substrate is scanned while being illuminated by the first illumination means 30 and the second illumination means 40. The light illuminated by both the illumination means 30 and 40 is reflected by the substrate, and the reflected light passes through an opening provided below the housing 11 and enters the optical system 12. Then, the light incident on the optical system 12 is condensed on the CCD line sensor 20. The CCD line sensor 20 photoelectrically converts the light received in this way, and captures the imaging area on the substrate as image data in a line sequential manner. In this embodiment, the first illumination unit 30 and the second illumination unit 40 irradiate the surface of the substrate with light so that a plurality of fine line patterns having a minute width extend in parallel. Even when the substrate surface is mirror-finished relatively smoothly, the pattern on the substrate can be clearly imaged. When the line spacing of the pattern on the substrate is large or the substrate surface is not so smooth, the second illumination unit 40 may be turned off and the first illumination unit 30 may be used for imaging as usual.

  FIG. 7 is an explanatory diagram for comparing the case where the substrate surface is imaged without turning on the second illumination means 40 and the case where the second illumination means 40 is turned on and the substrate surface is imaged. Among these figures, FIG. 7A shows a part of an image taken without turning on the second illumination means 40, and FIG. 7B shows an image taken with the second illumination means 40 turned on. The part is shown schematically. Note that all the patterns P extend in a direction orthogonal to the CCD arrangement direction.

  Comparing FIG. 7 (a) and FIG. 7 (b), FIG. 7 (a) shows a small density difference between the portion P where the pattern is printed and the portion (groove portion) N where the pattern is not printed. Whereas it is unclear, in FIG. 7B, the boundary between the portion P where the pattern is printed and the portion N where the pattern is not printed is clear. Thus, it is clear that the pattern printed on the board is clearly captured when the second illumination unit 40 is turned on and the image is taken without the second illumination unit 40 being turned on. Thus, when this image is binarized and comparatively inspected, the contour of the pattern P is clearly discriminated.

  From the experimental results, if the difference between the first post-projection irradiation angle θ1 and the second post-projection irradiation angle θ2 is θ, the pattern printed on the substrate is 10 ° <| θ | <60 °. It has been found that a clearer image can be taken, and that a pattern printed on the substrate can be taken more clearly when 20 ° <| θ | <45 °. The first post-projection irradiation angle θ1 is preferably approximately 0 °.

  In the embodiment described above, the second illumination unit 40 has a configuration in which a plurality of LEDs 41 are arranged on the second support member 44 in a direction crossing the arrangement direction of the LEDs 31 in the first illumination unit 30. Although the first post-projection irradiation angle θ1 and the second post-projection irradiation angle θ2 are different, the second illumination unit may be provided with a light guide unit such as a prism or an optical fiber. In this case, the linear light source in the first illumination unit 30 and the linear light source in the second illumination unit 40 are arranged in parallel, and the first post-projection irradiation angle θ1 and the second post-projection are arranged by the light guide unit. The irradiation angle θ2 may be different.

  In the embodiment described above, six first illumination units are provided. However, the first illumination unit may be a single unit or a plurality other than six units.

  Furthermore, in the embodiment described above, a pair of second illumination means 40 is disposed on both sides of the first illumination means 30 in the direction in which the LEDs 31 are arranged, but a plurality of pairs of second illumination means 40 are arranged. May be provided.

1 is a side sectional view showing an imaging head 10 in a substrate inspection apparatus according to the present invention. It is sectional drawing which shows the imaging head 10 in the board | substrate inspection apparatus based on this invention from the AA direction in FIG. It is a block diagram which shows the main electrical structures of the board | substrate inspection apparatus which concerns on this invention. It is a perspective view which expands and shows the 1st illumination means 30 and the 2nd illumination means 40. FIG. 3 is an explanatory diagram schematically showing a positional relationship among a CCD line sensor 20, a first illumination unit 30, and a second illumination unit 40. FIG. It is explanatory drawing which shows the irradiation angle of the light at the time of projecting the light radiate | emitted from the 1st illumination means 30 and the 2nd illumination means 40 on the reference plane abcd in FIG. It is explanatory drawing which compares what imaged the board | substrate surface, without lighting the 2nd illumination means 40, and what imaged the board | substrate surface by turning on the 2nd illumination means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Imaging head 11 Case 12 Optical system 20 CCD line sensor 30 1st illumination means 31 LED
32 linear Fresnel lens 33 lenticular lens 34 first support member 35 cover member 36 pillar member 40 second illumination means 41 LED
42 Linear Fresnel Lens 43 Lenticular Lens 44 Second Support Member 45 Cover Member 50 Moving Means 60 Control Unit 61 ROM
62 RAM
63 CPU
64 Interface θ1 Irradiation angle after the first projection θ2 Irradiation angle after the second projection P The part where the pattern is printed N The part where the pattern is not printed

Claims (7)

In a substrate inspection apparatus that images a substrate surface by a CCD line sensor in which a large number of CCDs are arranged,
A substantially linear light irradiation unit disposed in a direction parallel to the CCD line-up direction in the CCD line sensor, and irradiates light toward a region imaged by the CCD line sensor on the substrate surface. 1 lighting means;
Projected on a reference plane that is disposed on both sides of the light irradiating portion in the first illumination means in the longitudinal direction and includes a number of CCDs in the CCD line sensor and a region imaged by the CCD line sensor on the substrate surface Further, the light emitted from the first illuminating means is irradiated toward a region imaged by the CCD line sensor on the substrate surface at an irradiation angle different from an irradiation angle after the projection onto the substrate surface. A second illumination means;
Moving means for moving the CCD line sensor, the first illuminating means, and the second illuminating means relative to the substrate in a direction perpendicular to the CCD line-up direction in the CCD line sensor;
A board inspection apparatus comprising: The board inspection apparatus according to claim 1,
The first illumination means is a substrate inspection apparatus having a configuration in which a plurality of LEDs are arranged in a direction parallel to a CCD arrangement direction in the CCD line sensor. In the board | substrate inspection apparatus of Claim 1 or Claim 2,
The second illuminating means is a substrate inspection apparatus having a configuration in which a plurality of LEDs are arranged in a direction intersecting with an arrangement direction of the LEDs in the first illuminating means. The substrate inspection apparatus according to claim 3,
A substrate inspection apparatus provided with a lenticular lens for uniforming the illuminance distribution on the substrate surface of the light emitted from the LED in the second illumination unit between the substrate and the LED in the second illumination unit . In the board | substrate inspection apparatus in any one of Claim 1 thru | or 4,
The plurality of LEDs in the second illuminating means is a substrate inspection apparatus disposed on substantially the same plane as the reference plane. In the board | substrate inspection apparatus in any one of Claim 1 thru | or 5,
The second illuminating means is a substrate inspection apparatus configured to be lit independently of the first illuminating means. An image pickup head having a CCD line sensor in which a plurality of CCDs are arranged is moved relative to the substrate to be inspected, and a wiring pattern on the substrate to be inspected is line-sequentially imaged. In board inspection equipment that inspects the quality of
The imaging head includes first illuminating means provided substantially parallel to the line-up direction of the CCD line sensors, and the first illuminating means are individually disposed at both ends of the CCD line sensor, and the CCD line A substrate inspection apparatus comprising: at least a pair of second illuminating units that illuminate toward the imaging region from both ends of the sensor.

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