JPH04236345A - Inspecting apparatus of solder ball - Google Patents

Abstract

PURPOSE:To detect a solder ball with good accuracy by binarizing with a plurality of binarizing levels, and generating inspecting windows corresponding to a plurality of inspecting areas. CONSTITUTION:Binarizing circuits 14, 16 binarize with different binarizing levels a dark-and-bright image signal (a) output from a photographing camera 13 which photographs the surface of a substrate where an FIC 12 illuminated by an illuminating device 11 is mounted. Binarized image signals (b), (d) are output from the circuits 14, 16. Window generating circuits 15, 17 generate a first and a second windows of a preset dimension at the parts of the binarized image signals (b), (d) corresponding to a first and a second areas between the leads of the FIC 2, extracting only the binarized image signals within the windows and outputting binarized image signals (c), (e) in the first and second windows, respectively. A judging circuit 18 checks the logic level of the signals (c), (e). When a signal of the indicated logic level is present, the circuit 18 outputs a signal (f) indicating that a solder ball is present. Accordingly, even when a solder ball has a part hard to be illuminated by the light, the ball can be detected with good accuracy.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a solder ball inspection device,
In particular, the present invention relates to a solder ball inspection device that inspects the presence or absence of solder balls between the leads of an FIC soldered to a printed circuit board.

0002

2. Description of the Related Art A conventional solder ball inspection device will be explained in detail with reference to the drawings. FIG. 3 is a block diagram showing an example of the conventional technology. The solder ball inspection device shown in FIG.
(B) between the leads of the FIC 12; (B) between the leads of the FIC 12; A window that generates a window with preset dimensions in a portion of the binarized image signal g corresponding to an area of , extracts only the binarized image signal within the window, and outputs it as a binarized image signal h within the window. A generation circuit 35, (C) a determination circuit 36 which checks the logic level of the in-window binarized image signal h and outputs a solder ball presence signal f when a signal with a specified logic level is present. be done.

FIG. 4 is a top view showing the principle of the apparatus shown in FIG. An inspection window 42 is generated between the FIC 40 and leads 41 and 41b. Since the solder balls 43 located between the leads reflect stronger light than other parts between the leads, in the binarization circuit 34, only the parts of the solder balls 43 have a logic level "1". Therefore, if there was a logic level "1" in the inspection window 42, it was determined that a solder ball was present.

0004

[Problems to be Solved by the Invention] The conventional solder ball inspection device described above can detect solder balls between the leads in the flat part where the leads are in contact with the pad, but cannot detect the solder balls in the parts where the leads are bent upward. As for the solder balls between the leads, the reflected light is reduced because the illumination light is difficult to hit, so the solder balls may be missed.
Furthermore, if the binarization level is set low so as not to overlook solder balls, there is a problem in that flux or the like may be mistakenly determined to be solder balls in areas where leads between leads are connected to pads.

[0005]

[Means for Solving the Problems] The solder ball inspection device of the present invention has the following features: (A) A grayscale image signal output from a camera that photographs the mounting surface of a board on which an FIC is mounted, which is illuminated by a lighting device. (B) first and second binarization circuits that binarize at different binarization levels and output first and second binarized image signals; generating first and second windows with preset dimensions in portions of the first and second binarized image signals corresponding to a second area; (C) first and second window generation circuits that extract only the digitized image signal and output it as binarized image signals within the first and second windows;
and a determination circuit that checks the logic levels of the first and second in-window binarized image signals and outputs a solder ball presence signal if a signal of a designated logic level is present.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. The solder ball inspection device shown in Figure 1 is (A)
The grayscale image signal a output from the camera 13 that photographs the mounting surface of the board on which the FIC 12 is mounted and which is illuminated by the lighting fixture 11 is binarized at different binarization levels to obtain a binarized image signal. The first and second two that output b, d
The digitization circuits 14 and 16 (B) create first and second windows with preset dimensions in the portions of the binarized image signals b and d corresponding to the first and second areas between the leads of the FIC 12; occurs, and the first
Extract only the binarized image signal in the second window,
first and second window generation circuits 15 and 17 outputting first and second intra-window binarized image signals c and e;
(C) A determination circuit 18 that checks the logic level of the in-window binarized image signals c and e and outputs a solder ball presence signal f if a signal of a specified logic level is present. .

FIGS. 2(a) and 2(b) are a top view and a side view showing the principle of the apparatus shown in FIG. 1. In Figure 2(a),
A situation is shown in which inspection windows 22 and 23 are generated between leads 21 and 21b of the FIC 12. The inspection window 22 is located at the flat portion where the lead contacts the pad, and the inspection window 23 is located at the portion where the lead is bent upward. FIG. 2(b) shows the leads 21, 21b.
This explains the positional relationship between the solder balls 24 and 25, and the part of the solder ball 24 on the flat part of the lead is 2
It becomes logic “1” by the value converting circuit 14, and 2 in the window
The digitized image signal c includes logic "1".

The binarization circuit 15, which binarizes the grayscale image signal a of the solder ball 25 in the part where the lead is bent upward, is designed to cope with less reflected light.
The binarization level is set low so that when a solder ball 25 is present, a logic "1" is output.

0010

Effects of the Invention The solder ball inspection device of the present invention performs inspection by adding a binarization circuit and performing binarization using a plurality of binarization levels to generate inspection windows corresponding to a plurality of inspection areas. This has the effect of accurately detecting solder balls located in areas that are difficult to reach with the irradiation light.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention.

2(a) and 2(b) are a top view and a side view showing the principle of the apparatus shown in FIG. 1;

FIG. 3 is a block diagram showing a conventional example.

FIG. 4 is a top view showing the principle of the device shown in FIG. 3;

[Explanation of symbols]

11 Lighting equipment 12 FIC 13 Cameras 14, 16 Binarization circuits 15, 17 Window generation circuit 18 Judgment circuit a Gray image signals b, d Binarized image signals c, e In-window binary image signal f
Solder ball presence signal

Claims (1)

[Claims] Claim 1: (A) irradiated by a lighting equipment;
The grayscale image signal output from a camera that photographs the mounting surface of a board on which a surface-mounted IC (hereinafter referred to as FIC) is mounted is binarized at different binarization levels, and the first and second two
a first and second binarization circuit that outputs a digitized image signal, (B
) generating first and second windows with preset dimensions in portions of the first and second binarized image signals corresponding to the first and second regions between the leads of the FIC; (C) first and second window generation circuits that extract only binary image signals within the first and second windows and output them as binary image signals within the first and second windows; a determination circuit that checks the logic levels of the binary image signals in the first and second windows and outputs a solder ball presence signal when a signal of a specified logic level is present. Inspection equipment.