JP3480187B2 - Inspection method for electronic component misalignment - Google Patents

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 positional deviation of an electronic component such as a square chip having two terminals.

[0002]

2. Description of the Related Art After an electronic component having two terminals is soldered to an electrode on a substrate, a displacement inspection as described below is performed. Here, FIGS. 7A and 7B are process explanatory views of a conventional method for inspecting the positional deviation of electronic components, and FIG.
Shows the case where the positional deviation is within the positional deviation allowable value and should be judged to be good, and FIG. 7B shows the case where the positional deviation exceeds the positional deviation allowable value and it should be judged to be defective.

In FIG. 7A, reference numerals 1 and 2 denote two electrodes, and two terminals 4 and 5 of the electronic component 3 are solders 6 and 7.
It is fixed to the electrodes 1, 2. Here, when illuminating the electronic component 3 from directly above and observing it with a camera, the portions of the terminals 4 and 5 and the electrodes 1 and 2 exposed above are bright because they reflect light directly above. To be observed.
However, since the solders 6 and 7 are inclined in a curved surface,
It does not reflect light directly above and is observed dark.

Therefore, in the conventional displacement inspection method for electronic parts, the positions of the electrodes 1 and 2 (known in advance)
, The inspection frames S1 and S2 are arranged, the terminals 4 and 5 (bright parts) are detected, the coordinates of the centers of gravity G1 and G2 of the bright parts are obtained, and the position of the electronic component 3 is determined from the coordinates of the centers of gravity G1 and G2. It was calculated and judged good or bad.

[0005]

However, in such a configuration, there is a case where a good judgment is erroneously made when it should be originally judged as a bad as described below.

That is, as shown in FIG. 7B, when the terminal 4 is completely detached from the electrode 1, the solder 6 applied to the electrode 1 and melted and solidified has a gentle mountain shape. It is on 1. Then, when illuminating from directly above and observing from directly above, the top of the solder 6 is almost flat and reflects light directly above. Therefore, when the inspection frame S1 is set similarly to FIG. 7A, the top portion 6 of the solder 6 is placed in the inspection frame S1.
The image of a exists as a bright image. At this time, the center of gravity G3 of the top portion 6a of the solder 6 which is a bright image is almost in the vicinity of the center of the electrode 1 and is erroneously recognized as a small positional deviation. As a result, it is erroneously determined as good. As described above, the conventional misalignment inspection method for electronic components has a problem in that erroneous determination is likely to occur and accuracy is low.

Therefore, it is an object of the present invention to provide a method for inspecting the positional deviation of electronic parts, which can improve the determination accuracy.

[0008]

According to the method for inspecting displacement of electronic parts of the present invention, there is a step of obtaining a luminance distribution on both sides of an electrode, and there is no brighter portion than the terminal in the obtained luminance distribution. If not, if not, the steps of detecting the position of the terminal on the electrode and the step of checking the positional deviation based on the detected position of the terminal are included.

Further, a step of setting a deviation detection line at a position deviated from the electrode by a positional deviation allowance value, and obtaining a luminance distribution of this deviation detection line, and a portion where the obtained luminance distribution is equal to or brighter than the terminal If there is, the step of setting a check area between this part and the electrode, the step of checking the area ratio or the number of pixels of a bright portion equal to or higher than the terminal in the check area, and the area ratio or the number of pixels Is determined to be defective when is greater than or equal to a predetermined value or exceeds a predetermined value.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for inspecting the positional deviation of an electronic component according to claim 1 includes a step of obtaining a luminance distribution on both sides of an electrode, and there is no bright portion equal to or more than a terminal in the obtained luminance distribution. If not, if not, the steps of detecting the position of the terminal on the electrode and the step of checking the positional deviation based on the detected position of the terminal are included.

According to a second aspect of the present invention, there is provided a method for inspecting a positional deviation of an electronic component, which comprises the steps of setting a deviation detection line at a position deviated from the electrode by a positional deviation allowance value, and obtaining a luminance distribution of the deviation detection line. When there is a bright spot equal to or higher than the terminal in the luminance distribution, a step of setting a check area between this spot and the electrode,
The method includes a step of checking the area ratio or the number of pixels of a bright portion equal to or higher than the terminal in the check area, and a step of determining a defect when the area ratio or the number of pixels exceeds or exceeds a predetermined value.

Therefore, in any of the above configurations, if the electronic component is misaligned, an abnormality that should not be originally present in the luminance distribution (the presence of a bright portion equal to or higher than the terminal) appears, so check this abnormality. By doing so, it is possible to reduce erroneous determination and improve the determination accuracy accordingly.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an inspection apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 8 is an XY table for positioning the board 9. The electronic component 3 is mounted on the board 9 as shown in FIG. 7 and then soldered. 10
Is a camera for observing the electronic component 3 on the substrate 9 from directly above, 1
Reference numeral 1 denotes an illumination that irradiates the field of view of the camera 10 with light from directly above. Then, the image output by the camera 10 is processed by the image processing unit 12 according to the flow described below, and the result of determination of good / defective is output to the control unit 13 that controls the entire apparatus.

Next, each process of the method for inspecting the positional deviation of the electronic component of the present embodiment will be described along the flowchart of FIG. 2 and with reference to FIGS. First, as shown in FIG. 3A, in this embodiment, four shift detection lines L1 to L4 are set on both sides of the electrodes 1 and 2. These deviation detection lines L1 to L4 are long and narrow linear areas each having a width of 1 pixel and a length of n pixels (the same as the lateral width of the electrodes 1 and 2).
The electrodes 1 and 2 are provided in parallel with the upper and lower edges of the electrodes 1 and 2 and are separated by a positional deviation allowance value A.

Then, as shown in FIG. 3, when the positional deviation is small and it should be judged as good, the flow is as follows. That is, in step 1, the luminance distribution on each of the deviation detection lines L1 to L4 is obtained. Then, in the obtained luminance distribution, it is checked whether or not there is a portion having a luminance equal to or higher than a threshold value (which is preset with the same value as the brightness of the terminals 4 and 5) (step 2).

Here, as shown in FIG. 3 (a), if soldered correctly, at least terminals 4 and 5 will have electrodes 1 and 2.
It is on the upper side, and the terminals 4 and 5 do not touch the deviation detection lines L1 to L4. Therefore, in the case as shown in FIG. 3A, the check result in step 2 is “none”, and the process proceeds to step 5.

After step 5, as in the conventional method for inspecting the positional deviation of electronic parts, as shown in FIG. 3B,
The inspection frames S1 and S2 are set, and the centers of gravity G1 and G of the terminals 4 and 5 are set.
The coordinates of 2 are obtained (step 5), the positional deviation is calculated based on these coordinates, and it is examined whether or not it is within the allowable range (step 6). If it is within the allowable range, it is determined to be good (step 7), and if it is not, it is determined to be defective (step 8).

Next, as shown in FIG. 4 (a), a case will be described in which a conventional electronic component position shift inspection method determines that the device is good, although it should be determined to be defective.

In this case, the terminal 4 is disengaged from the electrode 1 and is in contact with the deviation detection line L1. Therefore, a part of the deviation detection line L is bright, and when the luminance distribution of the deviation detection line L1 is obtained in step 1 and the luminance is checked in step 2, the result is “present” and the process proceeds to step 3. .

Here, if there is a portion of the luminance distribution that is equal to or larger than the threshold value, it is not determined immediately as defective.
This is because the luminance distribution may be disturbed by noise or the like, as described later.

Now, in step 3, as shown in FIG. 4B, a check area C is set between the electrode 1 and the portion on the deviation detection line L1 where the luminance is equal to or higher than the threshold value. As the check area C, one side is a rectangular area having a positional deviation allowance value A. Then, in the check area C, the number of pixels equal to or larger than the threshold value described above is obtained (step 4). Then, if the number of pixels is equal to or larger than a predetermined value, it is determined to be defective (step 8). On the other hand, if it is less than the predetermined value, the processing shifts to the processing after step 5 described above.

Here, since the area around the abnormal portion is inspected planarly by the check area C, if this portion is brightened by the terminal 4 as shown in FIG. 4B. If so, the flow of steps 4 to 8 is followed, and it is correctly determined as defective. On the other hand, if an abnormality occurs due to noise, the noise is present in a scattered manner, so the check area C does not become bright on average, and a planar inspection by the check area C is performed. Thus, it can be prevented that the defect is erroneously determined. The determination in step 4 may be made based on the area ratio instead of the number of pixels as described above.

Next, the case where there is noise will be described in detail with reference to FIG. In the example of FIG. 5, although the electronic component 3 is correctly soldered, the flux 14, 1
5 exists, light and dark portions 14a and 15a are present in a part of the fluxes 14 and 15, and a part 14a thereof is in contact with the deviation detection line L2.

In such a case. In FIG. 2, the process proceeds to step 1 (FIG. 5A) to step 2 to step 3 to step 4 (FIG. 5B). However, as described above, there are few bright parts in the check area C, the result of step 4 is less than the predetermined value, and the processes of steps 5 and 6 are performed (FIG. 5C). Besides this,
Although a part of the circuit pattern formed on the substrate and the reflected light from other parts are also included in the part of the noise, it can be dealt with in the same manner as above.

Further, as shown in FIG. 6, an unnecessary electronic component 16 is scattered near the electronic component 3, and the scattered electronic component 1
The terminal 17 of 6 may be close to the electrode 2. Even in such a case, an abnormality is found in the deviation detection line L4, the inspection result in the check area C moves to Steps 4 to 8, and it can be determined as defective. In this case, the correctly soldered electronic component 3 is determined to be defective, but since the scattered electronic components 17 may cause a short circuit or the like, it is determined to be defective and the operator is alerted. However, there is no problem and it is convenient to prevent accidents.

[0027]

Since the present invention is constructed as described above,
It is possible to suppress erroneous determination and improve the determination accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram of an inspection device according to an embodiment of the present invention.

FIG. 2 is a flowchart of a method for inspecting a positional deviation of an electronic component according to an embodiment of the present invention.

FIG. 3 (a) is a process explanatory view of an electronic component position shift inspection method according to an embodiment of the present invention. FIG. 3 (b) is a process explanatory diagram of an electronic component position shift inspection method according to an embodiment of the present invention.

FIG. 4 (a) is a process explanatory view of the electronic component position shift inspection method according to the embodiment of the present invention. FIG. 4 (b) is a process explanatory diagram of the electronic component position shift inspection method according to the embodiment of the present invention.

FIG. 5 (a) is a process explanatory diagram of the electronic component position shift inspection method according to the embodiment of the present invention. FIG. 5 (b) is a process explanatory diagram of the electronic component position shift inspection method according to the embodiment of the present invention. ) Process explanatory drawing of the position shift inspection method of the electronic component in one embodiment of the present invention

FIG. 6 is a process explanatory diagram of the method for inspecting the positional deviation of the electronic component according to the embodiment of the present invention.

FIG. 7A is a process explanatory view of a conventional electronic component position shift inspection method. FIG. 7B is a process explanatory diagram of a conventional electronic component position shift inspection method.

[Explanation of symbols]

1, 2 electrodes 4, 5 terminals A misalignment tolerance L1, L2, L3, L4 Deviation detection line C check area

Continuation of the front page (56) Reference JP-A-5-209727 (JP, A) JP-A-6-288931 (JP, A) JP-A-5-264222 (JP, A) JP-A-63-181079 (JP , A) JP-A-3-131983 (JP, A) JP-A-62-261048 (JP, A) JP-B-5-40241 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) G01B 11/00-11/30 H05K 13/08 G06T 1/00 G06T 7/00

Claims (3)

(57) [Claims] 1. When inspecting a positional deviation of an electronic component mounted so that a terminal is located on an electrode, a step of obtaining a luminance distribution on both sides of the electrode and a step of obtaining a luminance distribution equal to that of the terminal or If there is no brighter spot than that, and if there is no bright spot, the step of detecting the position of the terminal on the electrode, and the step of checking the positional deviation based on the detected position of the terminal Misalignment inspection method. 2. When inspecting a positional deviation of an electronic component mounted so that a terminal is located on an electrode, a deviation detection line is set at a position deviated from the electrode by an allowable positional deviation value,
A step of obtaining the luminance distribution of this deviation detection line; a step of setting a check area between this portion and the electrode when there is a bright portion equal to or higher than the terminal in the obtained luminance distribution; Including a step of checking the area ratio or the number of pixels of a bright portion which is equal to or more than the terminals in the area, and a step of judging a defect when the area ratio or the number of pixels exceeds or exceeds a predetermined value. A method for inspecting displacement of electronic parts, characterized by: 3. The method for inspecting the positional deviation of an electronic component according to claim 2, wherein one side of the check area is a rectangular area having the positional deviation allowable value or less.