JP2000292122A - Positioning inspection method for bump module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time required for positioning a camera in a shorter time while holding high accuracy. SOLUTION: An oblique ray lighting means 5 is provided to light a bump module 1 comprising a number of protrusion parts 3... arranged in a specified configuration on a circuit board 2 from the direction aslant to the optical axis of a camera 4 and a coaxial lighting means 6 to light the bump module 1 from the same direction with the optical axis of the camera 4. After the camera 4 is moved roughly to the position of the interface of the bump module 1, the protrusion parts 3... alone are taken in as image by the oblique ray lighting from the oblique ray lighting means 5 and the camera 4 is moved to the interface area of the bump module 1. Thereafter, the protrusion parts 3... are lighted by the coaxial lighting from the coaxial lighting means 6 and the images of the protrusion parts 3... are taken in to inspect the protrusion parts 3....

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting a position on a bump module. More specifically, the present invention relates to an improvement in a positioning means at the time of inspecting a bump module formed by a plurality of protrusions such as solder.

[0002]

2. Description of the Related Art In recent years, the spread of CSP (chip size package) and the like has rapidly spread, and the degree of integration of a bump module has been increasing year by year, and the size of the module has been increasing. Normally, a camera is often used to inspect the projections (bumps) that form the bump module. However, when the size of the bump module does not fit within the camera's field of view, it is common to perform a separate inspection. is there. In this case, the module size and the camera field-of-view range are known, the number of divisions is determined in advance, and the positioning of the camera with respect to the bump module needs to be highly accurate.

As a method of accurately positioning a camera, there is a method of detecting a position by using a board recognition mark 101 provided on a circuit board 2 as shown in FIG. In this method, a camera and illumination for recognizing the board recognition mark 101 are prepared for positioning on the bump module 1, and the board recognition mark 101 is processed by image processing according to, for example, a flow shown in FIG.
The camera is positioned at the target bump module by recognizing several parameters of the target and calculating conversion parameters between the board coordinates and the robot coordinates.

[0004]

However, in the above-described method, two or more board recognition marks 101 are processed by image processing and positioned on the bump module 1, so that the camera is moved as shown in FIG. There is a problem that a corresponding time is lost for positioning by moving (or moving the circuit board).

Further, since the above-described method is indirectly recognized, the accuracy of the circuit board 2 and the accuracy of the device are easily affected, and the higher the accuracy of the bump module 1, the more the board recognition mark 101 alone is not enough. It is necessary to increase the number of times of viewing other component recognition marks and the like. For this reason, depending on the required accuracy, there is a possibility that the board recognition mark recognition operation time which is not directly related to the original inspection may increase. Further, since a camera for recognition and a camera for inspection for the original purpose must be prepared, there is a disadvantage that the number of cameras increases.

Accordingly, an object of the present invention is to provide a method of positioning and inspecting a bump module which can position a camera in a short period of time while maintaining high accuracy and reduce the time required for inspection.

[0007]

In order to achieve the above object, a method for inspecting the positioning of a bump module according to the first aspect of the present invention is directed to a bump module comprising a large number of protrusions arranged in a predetermined shape on a circuit board. Capturing an image of the bump module with a camera, positioning the camera at a predetermined position of the bump module, and inspecting the bump module. The oblique illumination unit illuminates the bump module obliquely with respect to the optical axis of the camera. And a coaxial illumination means for illuminating the bump module from the same direction with respect to the optical axis of the camera. After the camera is approximately moved to the boundary position of the bump module, only the projection is captured as an image by oblique illumination by oblique illumination. To move the camera to the boundary area of the bump module. Illuminated by illuminating the protrusion, it is obtained by providing a way to examine the projections capturing the image of the protrusions.

In this case, oblique light illuminating a number of projections is reflected by a curved surface at the tip edge of the projections and partially enters the camera. For example, a pattern or a resist on a circuit board other than the projections is used. Light reflected by the portion does not enter the camera. For this reason, in the image of the camera at the time of the oblique light irradiation, only the protrusions shine in an arc shape, a ring shape, and the like, and portions other than the protrusions are not reflected, so that only the shape of the protrusions can be detected. In other words, when oblique light is emitted, it is possible to detect and recognize only the position of the protrusion where the leading edge shines irrespective of the circuit on the circuit board or the board coordinates.

The use of such an oblique image makes it possible to detect the camera position without relying on a marking such as a board recognition mark.
The time required for inspection can be reduced without losing time for recognizing the board recognition mark. In addition, in such positioning, since the position of the protrusion can be directly detected to eliminate an error in forming the protrusion, the positioning can be performed with higher accuracy than when the detection is performed using the board recognition mark. can do. In addition, there is also an advantage that a camera for mark recognition is not particularly required, so that only a camera for inspection is sufficient.

According to a second aspect of the present invention, in the positioning inspection method for a bump module according to the first aspect, the bump module has a large number of protrusions arranged in a square shape, and the boundary position is a square corner. Department. in this case,
By bringing the square corner to the corner of the camera's field of view, many projections can be captured in the image at once.

[0011] The invention according to claim 3 is the invention according to claim 1 or 2.
In the positioning inspection method for a bump module described above, the circuit board is installed at a predetermined position, and an error is generated when the boundary area of the bump module by oblique illumination by the oblique illumination unit is smaller than a predetermined range. Things. If the boundary area of the bump module is not larger than the predetermined range, it is considered that the circuit board is not installed at the predetermined position and some trouble has occurred.

According to a fourth aspect of the present invention, in the method for inspecting positioning on a bump module according to the second aspect, only the projections are captured as images by oblique illumination by oblique illumination means, and brightness levels in the X-axis direction and the Y-axis direction are obtained. Thus, the position of the corner of the bump module is obtained, and the camera is moved to the position of the corner. Because there is a difference in the amount of light detected when scanning a row with protrusions and when scanning a row without protrusions, there is a step in the graph showing the brightness level obtained by connecting these detected light amounts, The position of the corner is indicated.

According to a fifth aspect of the present invention, in the positioning inspection method for a bump module according to the fourth aspect, the brightness level in the X-axis direction and the Y-axis direction is determined by adjusting the reflection level of the plurality of projections reflecting the brightness level. This is expressed by the total amount of light when the projection module scans the bump module in the X-axis direction or the Y-axis direction by the projection means. In this case, since the brightness level is detected for each row to be scanned, the boundary between the row with the projection and the row without the projection can be accurately recognized. Further, even when the arrangement of the projections is not parallel to the scanning direction, it is easy to detect the presence or absence of the projections.

According to a sixth aspect of the present invention, in the method for inspecting the positioning on a bump module according to any one of the first to fifth aspects, a projecting portion near an end among a large number of projecting portions captured in an image is provided. The next movement position of the camera is set based on the inclination obtained using both coordinates of the projection apart from the projection. In this case, since the inclination is obtained from the coordinates of both projections, the camera can be moved to an appropriate position in consideration of the inclination.

According to a seventh aspect of the present invention, in the method for inspecting the positioning on a bump module according to any one of the first to sixth aspects, the field of view of the camera is large enough to capture only a partial area of the entire bump module. This is what is set. In this case, the inspection time is shortened by positioning the camera so that the projection is sufficiently taken in the field of view of the camera.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

FIGS. 1 to 10 show an embodiment of a method for inspecting the positioning of a bump module according to the present invention. The method for inspecting the positioning of the bump module on the bump module according to the present embodiment includes a plurality of projections 3,.
The camera 4 captures an image of the bump module 1 composed of a camera, and positions the camera 4 at a predetermined position of the bump module 1 for inspection. That is, after the camera 4 is roughly moved to the boundary position of the bump module 1, only the projections 3,..., 3 are captured as images by oblique illumination by the oblique illumination means 5, and the camera 4 is moved to the bump module 1 based on this image. ., 3 are illuminated by the coaxial illumination by the coaxial illuminating means 6, and an image is taken in to inspect the bump module 1.

The bump module 1 to be inspected in this embodiment is formed by arranging a large number of projections 3,..., 3 on a circuit board 2 as shown in FIG.
In the present embodiment, the projections 3,..., 3 are provided in a grid pattern as shown in FIG. 9, and a set of these is arranged so as to be square in one module. Therefore, the four corners of the bump module 1 are square corners 7 as shown in FIG. 10, and each corner 7,..., 7 is a boundary position which is a standard when positioning the camera 4. As shown in FIG. 2, the protrusion 3 forming the bump module 1 has a distal end portion having a larger diameter than a base end portion and a distal end edge portion 3.
a is formed to be a smooth curved surface,
They are provided at equal intervals on a circuit board 2 installed at a predetermined position.

The camera 4 is a device for taking in an image for checking whether or not desired projections 3,..., 3 are formed on the surface of the bump module 1. In this embodiment, as shown in FIG. In order to capture an image from directly above the bump module 1, for example, a camera head 11 as shown in FIG. 3 is provided, and the optical head is provided downward with the optical axis perpendicular to the circuit board 2. The camera 4 is movable by being mounted on a three-axis orthogonal robot having horizontal X and Y axes and a vertical Z axis, and is provided so that it can be moved to a predetermined position of the bump module 1 and positioned. ing.

The field of view 12 of the camera 4 in this embodiment is large enough to take in only a part of the entire bump module 1 as shown in FIG. 10, for example. It is narrower than the range of one bump module 1. Therefore, the camera 4 can be used only for capturing the image once.
Cannot be inspected as a whole, and moves after capturing an image to capture the next image.

The oblique light illuminating means 5 is a member for illuminating the bump module 1 from an oblique direction with respect to the optical axis of the camera 4. For example, even if the oblique light illuminating means 5 is provided so as to emit light from different directions as shown in FIG. Alternatively, it may be provided so as to emit light only from a certain direction. In this embodiment,
For example, as shown in FIG. 1, a circular illuminating means is arranged on the upper part of the bump module 1 so that light is radiated from different directions. I try to shine light from.

The coaxial illumination means 6 is a means for illuminating the bump module 1 from the same direction with respect to the optical axis of the camera 4 and directing the light perpendicular to the circuit board 2. As shown in FIG. 1, the coaxial illumination unit 6 of the present embodiment is formed by a light emitting device 9 that emits light in the horizontal direction, and a reflection unit 10 including a half mirror provided vertically above the bump module 1. Is arranged so that the reflected light of the reflecting means 10 is parallel to the optical axis of the camera 4, but the configuration is not particularly limited as long as the bump module 1 can be illuminated with light parallel to the optical axis. Absent.

Although not shown in detail, a binarizing means 14 for taking out light of a certain brightness or more, a switching means 15 for instantaneously switching between oblique illumination and coaxial illumination generated by the oblique illumination means 5 and the coaxial illumination means 6. , A projection unit 16, an AD conversion unit 13, a module angle size registration unit 17, a conversion parameter acquisition bump (projection) position registration unit Each device such as 18, which is provided alongside the oblique illumination unit 5 and the coaxial illumination unit 6, functions according to the flow shown in FIG.

The positioning inspection method for the bump module according to the present embodiment is performed as follows in accordance with the flow shown in FIG. In the present embodiment, it is assumed that four bump modules 1,..., 1 are uniformly distributed and arranged at four corners as shown in FIG.

First, the camera 4 is roughly positioned while the corner 7 of the bump module 1 is within the visual field range 12 (step 1). In the present embodiment, the position of the circuit board 2 to be positioned is input in advance and is known from the viewpoint of the robot, so that rough positioning on the corner 7 of the bump module 1 is possible. Here, for example, when the arrangement of the projections 3,..., 3 is oblique to the circuit board 2, a part of the bump module 1 viewed from the camera 4 appears as shown in FIG. In this embodiment, the parallelism between the bump module 1 and the camera 4 can be adjusted mechanically.

Next, oblique illumination is applied to the bump module 1 to illuminate only the protrusions (bumps) 3,..., 3 (step 2). At this time, the oblique illumination is illumination close to parallel light, and the pattern, resist, and the like on the circuit board 2 do not shine when viewed from the camera 4 because reflected light does not return to the camera 4. On the other hand, the protrusions 3 constituting the bump module 1
.., 3 are formed in such a manner that the surface of the front edge 3a is formed into a smooth curved surface and rounded as shown in FIG. To reflect. Therefore, as shown in FIG. 6 and the like, the protruding portions 3,..., 3 constituting the bump module 1 appear to shine in the shape of an arc or a ring at the tip end portion 3a. Regardless of the circuit on the substrate 2 or the substrate coordinates, the position of only the protruding portions 3,..., 3 where the front edge 3a shines can be detected and recognized.

Then, the corner 7 of the bump module 1 is determined by the projection means 16 (step 3).
In the present embodiment, the projection unit 16 performs projection in both the X direction and the Y direction to detect the brightness level. Specifically, as shown in FIG. 7, when the projection means 16 runs in a streak shape along the X-axis and the Y-axis parallel to the edge of the circuit board 2 and scans the reflected light, and when one line is scanned, The sum of the detected light amounts is shown in a graph as a brightness level.

When scanning is performed in this manner, there is a difference in the amount of light detected between when a row having the projection 3 is scanned and when a row having no projection 3 is scanned. In the graph indicating the brightness level, a step occurs as shown in FIG. Therefore, a straight line passing through the step portion is drawn in parallel with the X axis or the Y axis, respectively, and a boundary line is provided to separate the portion having the projection 3 from the portion having no projection. The field of view of the camera 4 is determined by the length in the X direction or the length in the Y direction (hereinafter, referred to as “module angle size”) of the area (boundary area 8) where the protrusion 3 is located among the areas divided by the boundary line. 1
2, the occupation range and the occupancy of the bump module 1 can be confirmed. If the arrangement of the projections 3,..., 3 is not parallel to the scanning direction, the brightness level of the projections 3,..., 3 becomes uniform, so that the presence or absence of the projections 3,. May be. The intersection of the two boundary lines at this time substantially coincides with the corner 7 of the bump module 1.

Here, it is checked whether the module angle size obtained as described above is equal to or larger than a predetermined value (step 4). If this module angle size is equal to or larger than the default value registered in the module angle size registration means 17, it is confirmed that the occupation ratio of the bump module 1 in the visual field range 12 is equal to or larger than a predetermined value. By moving to the field of view 1
2 can take in the bump module 1.

On the other hand, when the module angle size is smaller than the predetermined value, the bump module 1
Since the occupation ratio is less than a predetermined value, it is determined that an image cannot be taken in a state in which the corner 7 is at an appropriate position and is treated as an error, and is processed by another route as shown in FIG.

When it is confirmed that the occupation ratio of the bump module 1 in the visual field range 12 is equal to or more than a predetermined value, the camera 4 is moved so that the corner 7 of the bump module 1 is located at the corner of the visual field range 12. It is positioned at the inspection position (step 5). At this time, the camera 4 only needs to be slightly moved from the state shown in FIG. 7, and after the movement, the corner 7 is located at the corner as shown in FIG. 8 is captured.

Then, in order to detect the positions of the protrusions 3,..., The oblique illumination is instantaneously switched to the coaxial illumination (step 6). This switching is performed by the switching means 15, whereby the process shifts from the process of detecting the corner 7 of the bump module 1 to the process of obtaining the conversion parameters as shown in FIG. When switching to the coaxial illumination, the distal end portion 3a, which has been shining in an arc or ring shape, can be seen as a whole shining as shown in FIG. At this time, the boundary area 8 of the bump module 1
, And only the projections 3,..., 3 are reflected.
Other than the projections 3,..., 3 such as patterns and resists are not shown. Also, even if the projections 3,..., 3 are missing, in the case of coaxial illumination, the pad that supports the base of the projection 3 shines, although not particularly shown.

Subsequently, necessary conversion parameters are detected. At this point, a screen as shown in FIG. 9 has been obtained. Out of the detected protrusions 3,..., 3, the protrusion 3a close to the corner 7 of the bump module 1 is taken out. Take out any protrusion 3b that is relatively separated from. At this time, the substrate coordinates of the projection 3a and the projection 3
Since the relative distance from “a” to the projection 3b can be obtained from the conversion parameter acquisition bump position registering unit 18, the mutual conversion parameters of the two projections 3a and 3b are obtained from the substrate coordinates and the vision coordinates. In addition, since the conversion parameters of the vision coordinates and the robot coordinates usually have a known calibration, the parameters are obtained for all the conversions of the board coordinates, the vision coordinates, and the robot coordinates.

When the conversion parameters are obtained in this manner, the data can be corrected using the conversion parameters, an inspection can be performed, and the camera 4 can be moved to the next division position and positioned (step 7). In this case, both projections 3
The camera 4 can be moved to an appropriate position in consideration of the inclination obtained from a and 3b. When the inspection position is completed, the inspection is completed, while when the inspection position is not completed, the operation of correcting the data is performed again (step 8).

As described above, when the inspection is performed by the positioning inspection method for the bump module 1 of the present invention, it is not necessary to recognize the board recognition mark 101 on the circuit board 2 every time the inspection is performed. There is no loss of time required for recognition. For this reason, marking such as the board recognition mark 101 is not required, and the time required for the inspection can be greatly reduced in total while ensuring high positioning accuracy.

Further, according to this positioning inspection method, since the bump module 1 can be directly recognized, a high-precision positioning inspection that is not affected by the accuracy of the circuit board 2 or the device can be performed. Further, since only one camera 4 is sufficient, the number of devices required for the inspection is small and the cost is not high.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, a large number of protrusions 3,.
Is a square bump module 1 arranged in a grid pattern
Has been described, but the inspection target is not limited to such a form. According to the present invention, even in the case of the bump module 1 in which the projections 3,... It is possible to locate and inspect.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When two or more substrate recognition marks 101 are processed by image processing and positioned on a bump module 1 by a conventional method, it takes about 1.5 to 2 seconds for positioning on the bump module 1. However, according to the positioning inspection method of the present invention, the time required for positioning the same bump module 1 can be reduced to 0.2 seconds or less.

[0039]

As is apparent from the above description, in the method for inspecting the positioning on the bump module according to the first aspect,
By irradiating the oblique light, the position of only the protrusion is detected regardless of the circuit on the circuit board or the board coordinates, so that the camera position can be detected without relying on the board recognition mark. Therefore, the time required for the inspection can be reduced without losing time for recognizing the board recognition mark. In addition, since the position of the protrusion is directly detected when positioning, the positioning can be performed with higher accuracy. In addition, a camera for recognition is not particularly required. It does not take.

According to the positioning inspection method for a bump module according to the second aspect of the present invention, a large number of projections can be taken into an image at a time by bringing a quadrangular corner of the bump module close to a corner of a field of view of a camera. Can be.

According to the method for inspecting the positioning of the bump module on the bump module, a case where the boundary area of the bump module does not exceed the predetermined range is treated as an error. Can be prevented.

According to the positioning inspection method for a bump module according to the fourth aspect, the position of the corner of the bump module is determined based on the brightness level of the image of only the projection, and the camera is moved to the position of the corner. Therefore, the camera can be moved to an appropriate position and many projections can be captured in the image.

Further, according to the method for inspecting the positioning on the bump module, the projection means can detect the brightness level for each row and accurately recognize the boundary between the row with the projection and the row without the projection. .

Further, according to the method for inspecting the positioning of the bump module on the bump module, the inclination of the next projection of the camera is determined from the inclination obtained using both coordinates of the projection near the end and the projection far from the projection. Since the moving position is set, the camera can be moved to an appropriate position.

According to the method for inspecting the positioning on the bump module according to the seventh aspect, the camera for capturing only a partial area of the entire bump module can be positioned at an appropriate position, and the inspection time can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a bump module, a camera, and the like showing an embodiment of a method for inspecting a positioning on a bump module according to the present invention.

FIG. 2 is a partial side view showing a shape of a protrusion of a bump module.

FIG. 3 is a plan view showing a configuration of a camera.

FIG. 4 is a flowchart showing an embodiment of a method for inspecting a positioning on a bump module according to the present invention.

FIG. 5 is a flowchart showing a flow of detecting a corner of a bump module by oblique illumination and obtaining a conversion parameter by coaxial illumination.

FIG. 6 is a diagram showing an image of a bump module reflected in a field of view when the camera is roughly positioned.

FIG. 7 is a diagram showing a brightness level when projection is performed on the image shown in FIG. 6 together with the image.

FIG. 8 is a diagram showing an image of a bump module when oblique illumination is applied after the camera is positioned.

FIG. 9 is a diagram illustrating an image of a bump module when coaxial illumination is applied after the camera is positioned.

FIG. 10 is a plan view showing an example of a form of a bump module.

FIG. 11 is a flowchart showing an example of a conventional method for inspecting the positioning of a bump module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bump module 2 Circuit board 3 Projection part 4 Camera 5 Oblique illumination means 6 Coaxial illumination means 7 Corner part 8 Boundary area

Claims (7)

[Claims] An image of a bump module composed of a large number of projections arranged in a predetermined shape on a circuit board is captured by a camera, and the camera is positioned at a predetermined position of the bump module to be inspected. In the positioning inspection method, oblique illumination means for illuminating the bump module obliquely with respect to the optical axis of the camera, and coaxial illumination means for illuminating the bump module from the same direction with respect to the optical axis of the camera. Prepared,
After approximately moving the camera to the boundary position of the bump module, oblique illumination by the oblique illumination unit captures only the projection as an image, and moves the camera to the boundary region of the bump module. Illuminating the projection by coaxial illumination by means,
A method for inspecting the positioning of a bump module, wherein an image of the projection is captured so that the projection can be inspected. 2. The bump module according to claim 1, wherein the bump module has the plurality of protrusions arranged in a square shape, and the boundary position is a corner of the square shape. Positioning inspection method. 3. The method according to claim 2, wherein the circuit board is installed at a predetermined position, and an error occurs when a boundary area of the bump module by the oblique illumination by the oblique illumination unit is smaller than a predetermined range. The inspection method for positioning a bump module according to claim 1 or 2. 4. The oblique illumination by the oblique illumination unit captures only the protrusion as an image, determines the position of the corner of the bump module based on the brightness levels in the X-axis direction and the Y-axis direction, and calculates the position of the corner. 3. The inspection method according to claim 2, wherein the camera is moved to a predetermined position. 5. The brightness level in the X-axis direction and the Y-axis direction is determined on the bump module in the X-axis direction or the Y-axis direction by projection means for detecting the projections of the reflected portions of the plurality of projecting portions. 5. The method according to claim 4, wherein the method is represented by a total amount of light when scanning in a direction. 6. The next movement position of the camera from the inclination determined using the coordinates of the projection near the end and the projection apart from the projection among the many projections captured in the image. 6. The method for inspecting the positioning on a bump module according to claim 1, wherein: 7. The bump module according to claim 1, wherein a field of view of the camera is set to a size that can capture only a partial area of the entire bump module. Positioning inspection method.