JP2008051583A - Inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the flaw of the overlapped part of a pattern of a double-sided substrate. <P>SOLUTION: The overlapped region 116 of a first metal pattern 110 containing a composited transmission image 114A and a second metal pattern 112 is set, on the basis of the preset density of the first transmission image 110A transmitted through the first metal pattern 110, the preset density of the second transmission image 112A transmitted through the second metal pattern 112 and the preset density of the composite transmission image 114A transmitted through both the first metal pattern 110 and the second metal pattern 112 of the radiation transmission image of the tape 22, having patterns formed on both sides. A computer detects the region 120 (disconnection 118) that is different from the predetermined density of the composite transmission image 114A as a flaw region, with respect to the overlapped region 116. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inspection apparatus for a double-sided board in which a metal pattern is formed on each of a front surface and a back surface.

  In recent years, there has been an increasing demand for miniaturization of semiconductor devices. For this reason, a semiconductor device of a chip size package (hereinafter referred to as CSP) in which the outer dimensions of the semiconductor device are reduced to almost the outer dimensions of a semiconductor element has been proposed. ing.

  As this CSP semiconductor device, for example, a semiconductor element is bonded to a substrate having an outer dimension slightly larger than the outer dimension of the semiconductor element with an adhesive or the like, and an electrode formed on the peripheral part of the semiconductor element and the peripheral part of the substrate A structure in which the electrodes formed on the substrate are electrically connected with a gold wire or the like, a substrate formed to have the outer dimensions of the semiconductor element and having an array of electrodes on the surface, and an array on the back side of the semiconductor element There have been proposed CSP semiconductor devices having various configurations, such as a configuration in which solder balls formed on are fused and electrically connected.

  In the manufacture of such a CSP semiconductor device, a large amount of CSP tape is used at once using a CSP tape in which a plurality of patterns such as wirings, electrodes, beam leads, and through holes formed corresponding to one chip are patterned. The package is to be manufactured.

  In this CSP tape, a conductive film such as a copper foil is formed on the surface of a base material such as a polyimide base material by vapor deposition or the like, and then a CSP wiring, an electrode, a beam lead, a through hole, etc. are used by using a normal etching technique. It is a long tape patterned by repeating a plurality of patterns.

  In manufacturing such a tape, after a pattern is formed, a disconnection of a wiring or a pattern defect such as a chip is inspected by an inspection apparatus as disclosed in Patent Document 1, for example. Detection of pattern defects by a conventional inspection apparatus optically reads a tape surface pattern by an image reading device such as a CCD, and automatically detects defects based on the read image. In this case, the read image can be converted into a binary image by image processing, and a pattern defect can be automatically detected.

  However, when the pattern is formed on both sides of the tape, the optical inspection requires a total of two inspections, the front surface inspection and the back surface inspection, and the pattern is formed on one side. In comparison, it takes twice the inspection time, and there is a problem that the pattern cannot be detected when a resist is provided on the pattern. Although it is conceivable to simultaneously photograph the front and back surfaces using two cameras, there is a problem that the apparatus configuration becomes complicated and the apparatus cost increases.

When inspecting a substrate provided with a resist, an inspector can check an X-ray transmission image photographed by an X-ray camera on a monitor to determine a pattern defect.
JP 2003-279498 A

  By the way, it is also conceivable to automatically detect a pattern defect in the same manner as an inspection apparatus that optically reads a pattern by processing an X-ray transmission image into a binary image.

  For example, in the X-ray transmission image, when a disconnection occurs in a region only with the front surface pattern (or a region only with the back surface pattern), the contour shape of the pattern changes, and therefore image processing (comparison with a preset reference) ) To determine that there is a defect.

  However, in the case of a double-sided substrate in which patterns are formed on both the front surface and the back surface, when an X-ray transmission image is converted into a binary image, the pattern on the front surface and the back surface pattern are overlapped with either pattern. When the disconnection occurs, the disconnection portion disappears on the binary image, and there is a problem that such a pattern defect cannot be detected by the conventional apparatus.

  The present invention has been made to solve the above problem, and an object of the present invention is to provide an inspection apparatus for a double-sided board capable of detecting a defect in an overlapping portion of a pattern of a double-sided board.

  The double-sided substrate inspection apparatus according to claim 1, wherein the radiation source irradiates a substrate having a first metal pattern formed on one surface and a second metal pattern formed on the other surface. Image generation means for receiving the radiation transmitted through the substrate and generating a radiation transmission image; a preset density of the first transmission image transmitted through the first metal pattern in the radiation transmission image; Based on a preset density of the second transmission image that has passed through the second metal pattern and a preset density of the composite transmission image that has passed through both the first metal pattern and the second metal pattern. Setting means for setting an overlapping area between the first metal pattern and the second metal pattern including the synthesized transmission image; and a predetermined density of the synthesized transmission image for the set overlapping area. It is characterized by having a defect detecting means for detecting a different region as a defect region.

  Next, the operation of the double-sided substrate inspection apparatus according to claim 1 will be described.

  In the double-sided board inspection apparatus according to the first aspect, the radiation is emitted from the radiation source toward the board, and the image generation unit receives the radiation transmitted through the board and generates a radiation transmission image.

  Since the first metal pattern is formed on one surface of the substrate and the second metal pattern is formed on the other surface, the first metal pattern and the second metal pattern are displayed on the radiation transmission image. Both are reflected.

  The setting means includes a predetermined density of the first transmission image transmitted through the first metal pattern, a predetermined density of the second transmission image transmitted through the second metal pattern, and a first density among the radiation transmission images. An overlapping region between the first metal pattern and the second metal pattern including the combined transmission image is set based on a preset density of the combined transmission image that has transmitted through both the metal pattern and the second metal pattern.

  Then, the defect detection means detects, as the defect area, an area different from the predetermined density of the combined transmission image with respect to the overlapping area set as described above. That is, in the region where the first metal pattern and the second metal pattern are overlapped (overlapping region), for example, if disconnection occurs in at least one pattern, Since the density is different from other parts, a region having a different density can be detected as a defect.

  As described above, according to the double-sided substrate inspection apparatus of the present invention, there is an excellent effect that it is possible to detect a defect in the overlapping portion of the pattern of the double-sided substrate, which was not possible with the prior art.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

  Hereinafter, an inspection apparatus 10 to which the present invention is applied will be described with reference to the drawings.

As shown in FIG. 1, the inspection apparatus 10 of the present embodiment is roughly provided with an unwinding unit 12, an optical inspection apparatus 14, an X-ray inspection apparatus 16, a marking apparatus 18, and a winding unit 20.
(Unwinding unit)
The unwinding unit 12 includes a roll 26 formed by winding a tape (for example, TAB tape, COF tape, etc.) 22 having a metal pattern on a synthetic resin film base and a spacer tape 24 together. An unwinding side reel tape 28 to be held and an unwinding side spacer tape shaft 30 to wind and hold the spacer tape 24 drawn together with the tape 22 are provided.

On the delivery side of the roll 26, a guide roller 32 for guiding the tape 22, a guide roller 34 for guiding the spacer tape 24, and a dancer 36 are arranged.
(Optical inspection equipment)
In the optical inspection device 14, a dancer 38, a roller 40, and a roller 42 are arranged in this order.

  The roller 40 and the roller 42 are horizontally disposed with a space therebetween, and a table 44 is disposed between the roller 40 and the roller 42.

  An optical image reading device 46 including a lens and a CCD line sensor is disposed above the center of the table 44.

  The tape 22 is stretched between the roller 40 and the roller 42, and is fed at a constant speed in one direction by the rotation of the roller 40 and the roller 42. The upper surface (circuit pattern, etc.) is taken. The rotation of the roller 40 and the roller 42 is controlled by a control device 48 including a computer or the like.

  The image information from the CCD line sensor is sent to a computer (not shown) that performs image processing of the control device 48, and the computer performs image processing based on the image signal (information) from the CCD line sensor to detect a pattern defect. Is detected optically.

The inspection image or the like can be displayed on the monitor 82 of the display device 80 described later.
(X-ray inspection equipment)
Next, in the X-ray inspection apparatus 16, a long dancer 52, a roller 54, and a roller 56 are sequentially arranged.

  The tape 22 is stretched between a roller 54 and a roller 56. The rollers 54 and 56 are rotated by a motor (not shown) controlled by the control device 48.

  An image generating device 58 is disposed between the roller 54 and the roller 56 above the transport path of the tape 22.

  The image generating device 58 includes a rotating drum 60. The rotary drum 60 has a rotation axis orthogonal to the transport direction of the tape 22 and parallel to the tape 22.

  A radiation image conversion layer containing a stimulable phosphor is disposed on the outer peripheral surface of the rotary drum 60.

  The rotating drum 60 is made of a metal that can prevent X-ray transmission. The rotating drum 60 may be one in which a metal plate such as lead is attached to the outer peripheral surface side (below the stimulable phosphor).

  The rotating drum 60 is rotated by a motor (not shown) controlled by the control device 48.

  Between the roller 54 and the roller 56, an X-ray generator 62 is disposed below the transport path of the tape 22, and the X-ray generator 62 irradiates the upper rotating drum 60 with X-rays. .

  The X-ray generator 62 includes a slit 64 made of a metal such as lead (not shown) on the X-ray irradiation side, and X-rays are irradiated toward the lower end of the rotary drum 60 in a long and narrow rectangular shape in the rotation axis direction. It has become so.

  The size of the X-ray irradiation area is the same as the width of the tape 22 in the width direction of the tape 22 on the transport path of the tape 22 (narrower than the width of the tape 22 depending on the inspection apparatus position). However, the dimension in the tape conveyance direction is set smaller than the dimension in the width direction of the tape 22.

  As the tape 22 is transported, the rotary drum 60 rotates counterclockwise (in the direction of arrow A in FIG. 1) in FIG. Since the X-ray generator 62 emits from one point (generation point P) of the X-ray tube, X-rays are emitted radially. Therefore, if the distance from the X-ray tube generation point to the tape 22 is A and the distance from the X-ray tube generation point to the photostimulable phosphor is B, the tape 22 is on the photostimulable phosphor B Since the image is magnified / A times, the peripheral speed of the rotary drum 60 is set to B / A times the conveying speed of the tape 22.

  Around the rotary drum 60, an excitation light irradiation device 63, a detection device 65, and an erasing light irradiation device 66 are sequentially arranged downstream of the X-ray irradiation position in the rotation direction.

  As shown in FIG. 2, the excitation light irradiation device 63 is driven by an excitation light source (for example, a laser diode) 68 that emits excitation light La that excites and emits a stimulable phosphor, and is driven by a motor 70. A polygon mirror 72 that deflects La, and an optical system 74 that collects excitation light deflected by the polygon mirror 72 on the photostimulable phosphor are configured. As this excitation light irradiation device 63, for example, an optical scanning device used in a laser printer or the like can be used.

  Excitation light La emitted from the excitation light source 68 passes through the polygon mirror 72 and the optical system 74 on the photostimulable phosphor provided on the outer peripheral surface of the rotary drum 60 in the main scanning direction (rotational axis direction of the rotary drum 60). 2 in the direction of arrow B in FIG.

  While the excitation light La repeatedly scans the stimulable phosphor in the main scanning direction, the stimulable phosphor moves in the sub-scanning direction (the rotating direction of the rotating drum 60) by the rotation of the rotating drum 60. Thus, the excitation light La scans the photostimulable phosphor two-dimensionally.

  In the excitation light irradiation device 63 of this embodiment, the excitation light La can be main-scanned from one end to the other end in the axial direction of the rotary drum 60 by the rotation of the polygon mirror 72.

  A detection device 65 is disposed in the vicinity of the excitation light irradiation device 63.

  The detection device 65 includes a light collecting guide 76 into which the photostimulated luminescent light Lb generated from the photostimulable phosphor is incident, and a photomultiplier that photoelectrically detects the photostimulated luminescent light Lb emitted from the exit end of the light collecting guide 76. A plier 78 is provided.

  The stimulated emission light Lb is incident on the photomultiplier 78, is then photoelectrically converted, and is output to the control device 48 as an electrical analog signal.

  In the control device 48, the analog signal output from the photomultiplier 78 is converted into a digital signal and stored in the image memory as two-dimensional image data. The image memory includes an area for storing an optically read image and an area for storing an image read by X-rays.

  The image information from the photomultiplier 78 is sent to a computer (not shown) that performs image processing of the control device 48, and the computer performs image processing based on the image signal (information) from the photomultiplier 78. Defect detection.

  As shown in FIG. 1, a display device 80 is connected to the control device 48. The display device 80 includes a video signal processing circuit that inputs two-dimensional data of an image memory, converts the data into a video signal, and outputs the video signal, and a monitor 82 that displays an image based on the video signal output from the video signal processing circuit. .

  The erasing light irradiation device 66 is provided with a long lamp (for example, a halogen lamp, a fluorescent lamp, a xenon lamp, etc.) along the axial direction of the rotary drum 60, and a reflector that collects erasing light from the lamp on the drum surface.

Although not shown, the apparatus is shielded from a lead plate or the like so that X-rays do not leak out from the X-ray inspection apparatus 16.
(Marking device)
In the marking device 18, a long dancer 84, a roller 86, a roller 88, and a short dancer 90 are arranged in this order.

  The tape 22 is stretched between a roller 86 and a roller 88.

Between the roller 86 and the roller 88, a marking unit 92 is disposed for marking at a predetermined position of the package pattern detected as having a defect.
(Winding unit)
The winding unit 20 is disposed downstream of the marking device 18 in the tape transport direction.

  The winding unit 20 includes a winding-side spacer tape shaft 94 that holds the spacer tape 24 formed in a roll shape, and a winding-side reel shaft 96 that winds the spacer tape 24 and the inspected tape 22 together. .

On the tape take-up side of the take-up reel shaft 96, rollers 98 and 100 for changing the transport direction of the tape 22 are arranged. A roller 102 and a short dancer 104 are disposed on the tape winding side of the winding side spacer tape shaft 94.
(Function)
Next, the operation of the inspection apparatus 10 of this embodiment will be described.

  First, an inspection procedure for the tape 22 having a metal pattern formed on one side will be described.

  The tape 22 drawn out from the roll 26 is conveyed onto a table 44, and the upper surface of the tape (the side on which the pattern is formed) is sequentially photographed by the image reading device 46. The image information output from the image reading device 46 is sent to the computer of the control device 48 for image processing, and the captured image of the tape 22 is displayed on the monitor 82 and whether or not the tape 22 is defective. Judgment is made.

  Here, when the defect is a foreign object, it is difficult to determine whether the defect is a metal foreign object that is a serious defect from an optical photographed image. In the inspection apparatus 10 of the present embodiment, when it is determined that there is an optical defect, an inspection by X-ray is automatically performed for confirmation (verification).

  The tape 22 that has passed through the image reading device 46 is conveyed at a constant speed, and a portion that is determined to be defective is imaged by the X-ray inspection device 16. Since the tape 22 has a metal pattern formed on a synthetic resin base film, dust other than the metal transmits X-rays better than the metal. It is not reflected and is not mistakenly recognized as a pattern defect. Therefore, excessive detection due to dust other than metal foreign matter is extremely reduced. On the other hand, metal dust that causes a short circuit or the like is reflected as a radiographic image, so that it can be determined that it is a serious defect. Therefore, the quality of the inspection result is improved by performing the inspection by X-ray.

  In the inspection apparatus 10 of the present embodiment, since the apparatus automatically determines a metal foreign object reflected in a radiographic image, it becomes possible to dispense with an inspector. Of course, the inspector may judge the defect by looking at the image on the monitor 82.

  In some cases, a resist is placed on a metal pattern and the pattern cannot be seen optically. Since resist transmits X-rays better than metal, an image of a pattern can be reliably obtained by X-ray inspection.

  Next, as shown in the schematic diagram of FIG. 3A, an inspection procedure for the tape 22 having a metal pattern formed on both sides will be described. FIG. 3A shows a part of the tape 22, in which the first metal pattern 110 is formed on the front surface and the second metal pattern 112 is formed on the back surface.

  When inspecting the tape 22 having the pattern formed on both sides, the X-ray inspection apparatus 16 performs imaging on all the portions where the pattern is formed.

  As shown in FIG. 3B, the radiation transmission image photographed by the X-ray inspection apparatus 16 includes a first transmission image 110A that has passed through the first metal pattern 110 formed on the tape surface side, Both of the second transmission images 112A transmitted through the second metal pattern 112 formed on the back surface of the tape are shown.

  The image processing computer (setting means of the present invention) of the control device 48 sets the preset density of the first transmission image 110A that has passed through the first metal pattern 110 in the radiation transmission image, and the second metal pattern. Based on the preset density of the second transmission image 112A that has passed through 112 and the preset density of the composite transmission image 114A that has passed through both the first metal pattern 110 and the second metal pattern 112. An overlapping region (a square region in FIG. 3B) 116 of the first metal pattern 110 and the second metal pattern 112 including the image 114A is set.

  Here, for example, as shown in FIG. 3C, when the first metal pattern 110 has a disconnection 118 at a portion where the first metal pattern 110 and the second metal pattern 112 intersect with each other. The radiation transmission image of the intersecting portion is as shown in FIG.

  Incidentally, in FIG. 3D, the density of the portion where the pattern is not formed is the highest, and the next darkest density portion is the first transmission image 110A transmitted through the first metal pattern 110 and the second metal. It is the 2nd transmission image 112A which permeate | transmitted the pattern 112, and the lowest density part turns into the synthetic | combination transmission image 114A which permeate | transmitted both the 1st metal pattern 110 and the 2nd metal pattern 112. FIG.

  The density of the broken line 118 portion is the same as the density of the first transmission image 110A because the X-rays pass only through the first metal pattern 110.

  The image processing computer (defect detection means of the present invention) of the control device 48 uses the region 120 (in this embodiment, different from the predetermined density of the combined transmission image 114A for the overlapping region 116 set as described above. A portion having the same density in the first transmission image 110A) is detected as a defect area.

  As described above, in the overlapping region 116, the density of the broken line 118 part and the density of the part that is not broken (the part where the two patterns overlap) are different. (Disconnection) can be easily detected by image processing.

When a defect is detected, the marking device 18 performs marking at a predetermined location corresponding to the defective pattern.
[Other Embodiments]
The excitation light irradiation device 63 of the inspection apparatus 10 can perform main scanning of the excitation light La from one end to the other end in the axial direction of the rotary drum 60 by the rotation of the polygon mirror 72. When the axial length is increased, the scanning range may be insufficient. In such a case, a plurality of excitation light irradiation devices 63 may be arranged in the axial direction of the rotary drum 60. In this case, scanning is performed so that one excitation light scanning beam and the other excitation light scanning beam adjacent to the excitation light scanning beam slightly overlap each other when viewed in the drum circumferential direction. When the stimulable phosphor is irradiated with excitation light a plurality of times, the stimulated emission light becomes weak, but it may be corrected by image processing.

  In the above embodiment, the photostimulable phosphor is provided on the outer peripheral surface of the rotary drum 60. However, the photostimulable phosphor may be provided on the surface of an endless belt that spans a pair of rollers. In this case, a lead plate or the like for shielding X-rays is arranged between the rollers so that the opposite photostimulable phosphor is not irradiated with X-rays.

  In the above embodiment, an example in which a defect in the long tape 22 is detected has been described. However, the inspection object is not limited to a tape shape, and may be shorter than a tape 22 such as a normal printed circuit board. good. In the case of such an object to be inspected, it may be conveyed by a belt conveyor made of a material that easily transmits X-rays such as rubber, and a plurality of objects to be inspected without using a plurality of imaging plates as in the prior art. Can be continuously inspected.

  In the above-described embodiment, the inspection is performed while the inspection object is being transported. However, the inspection can be similarly performed even if the inspection object is fixed and the X-ray inspection apparatus 16 is transported.

  Further, in the inspection apparatus 10, X-rays transmitted through the tape 22 are received by the radiation image conversion layer including the stimulable phosphor provided on the outer peripheral surface of the rotary drum 60, and the stimulated emission light from the stimulable phosphor is received. However, the present invention is not limited to this, and a general X-ray camera using an image intensifier or the like may be used as the X-ray inspection apparatus.

It is the block diagram which looked at the inspection apparatus from the front. It is a perspective view of an excitation light irradiation apparatus and a detection apparatus. (A) is a plan view seen from the tape surface side showing a part of the tape, (B) is a radiation transmission image of a part of FIG. 3 (A), and (C) shows a part of the tape with a disconnection. It is the top view seen from the tape surface side, (D) is a radiation transmission image of a part of FIG.3 (C).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inspection apparatus 16 X-ray inspection apparatus 22 Tape 46 Image reading apparatus 48 Control apparatus

Claims (1)

A radiation source for irradiating a substrate having a first metal pattern formed on one surface and a second metal pattern formed on the other surface;
Image generating means for receiving the radiation transmitted through the substrate and generating a radiation transmission image;
Among the radiation transmission images, a predetermined density of a first transmission image transmitted through the first metal pattern, a predetermined density of a second transmission image transmitted through the second metal pattern, and the first The overlapping region of the first metal pattern and the second metal pattern including the composite transmission image based on a preset density of the composite transmission image transmitted through both the metal pattern and the second metal pattern A setting means for setting
For the set overlapping region, defect detection means for detecting a region different from a predetermined density of the combined transmission image as a defect region;
An inspection apparatus for a double-sided board, comprising:

Images