JPH1038951A - Inspection method for ic mounting board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inspection method in which a pattern can be checked without replacing an IC as a nondefective product by a method wherein a process in which a pattern disconnection and a soldering defect between respective pin erection positions for the IC are inspected is added to a process in which the IC is inspected. SOLUTION: A package 1 for a short circuit is constituted of a pressure plate 2 in which many probes 3 are attached to side ends so as to correspond to all pins 12 at an IC 11 and in which a guide hole 4 is made in the central part and of a guide plate 5 in which through holes 6, into and through which the probes 3 are inserted and passed, are made in side ends and in which a slide guide 7 used to hold a coiled spring 8 in the circumference is erected and installed in the central part on the surface. Then, the IC 11 which is mounted on an IC mounting board is covered with the package 1 for the short circuit, a circuit on the IC mounting board is electrified, and a pattern disconnection and a soldering defect to the IC from pin erection positions of the IC 11 covered with the package 1 for the short circuit are inspected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC (IC part) mounting board, in particular, an IC mounted with an LSI such as a QFP.
The present invention relates to a method for inspecting a mounting board.

[0002]

2. Description of the Related Art Due to rapid technological innovation in the electronics industry today, ICs (integrated circuits) are becoming more diversified and denser, making it very difficult to judge the quality of a single product. Similarly, the density of IC mounting boards has been increasing.

[0003] As a device for judging the quality of this IC mounting board, there is a device currently called an in-circuit tester. In this in-circuit tester, the pass / fail judgment procedure is to first check the pattern between connectors and between ICs in an open test, short-circuit all the nets and check for short-circuits and bridges in the network, and use an analog test to test resistors and capacitors. And the like, and finally, an IC test is performed, and a test pattern is individually given to judge pass / fail.

As described above, this apparatus individually tests mounted components and determines that the mounting board is non-defective if all components are non-defective. When checking the pattern between components, it is determined whether pins are set at both ends of the pattern and whether or not the pattern is short-circuited.

[0005]

However, in today's high-density boards, individual patterns in a circuit pattern are very thin, and surface mount components (QFP or chip components having a pin interval of 1 mm or less in pitch) are required. And so on), making it difficult to even set up one probe per net to perform a test.

In addition, since the test pattern of the IC is limited and only the defect of the input / output portion is actually detected, if it is determined that the IC is defective, it is determined whether the IC is defective or not from the pin setting position (solder portion). It is necessary to determine whether the pattern has run out. Therefore, replace the IC and if it is still defective, from the viewpoint of whether the pattern is
The pattern is checked one by one. For example, assuming a 100-pin IC, it can be understood that this pattern check requires a lot of time.

[0007] In short, the conventional test process has a specific I
C (Especially because the pitch is narrow,
Contrary to C), there was no step of inspecting a broken pattern or a solder defect from the pin stand position to the IC by using any technical means. Therefore, the breakage of the pattern from the pin setting position to the IC and the defective solder were also determined by the inspection by the functional test of the IC.

[0008] The inspection method of the IC mounting board of the present invention comprises:
The purpose of the present invention is to solve the above-mentioned drawbacks of the conventional example, and to perform a pattern check without exchanging non-defective ICs.

[0009]

Means for Solving the Problems That is, according to the present invention,
In the method of inspecting a C-mounted board, in the step of inspecting the IC mounted on the IC-mounted board, a step of inspecting a pattern break and a solder defect between respective pin standing positions of the IC is added to the step of inspecting the IC. It is characterized by the following.

An inspection method of an IC mounting board according to the present invention comprises:
In the above, it is also characterized in that the means for inspecting a broken pattern and a solder defect between the pin standing positions of the IC includes a plurality of probes and is formed of a short-circuit package in which the probes are conducted.

An inspection method of an IC mounting board according to the present invention comprises:
As described above, the process of inspecting the IC includes a process of inspecting the conduction state such as a broken pattern from the pin stand position to the IC and a conduction defect such as a solder defect, which has been conventionally difficult. It is possible to check for defects in the continuity state, and to significantly reduce the inspection time of the IC mounting board.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of a method for inspecting a mounting board will be described using an example.

In FIG. 1, reference numeral 1 denotes a short package that shorts between pins over an IC mounted on an IC mounting board.

The short package 1 has an IC 11
A large number of probes 3 are attached to the side ends corresponding to all the pins 12, and a pressing plate 2 having a guide hole 4 formed in the center and a through hole 6 through which the probe 3 is inserted are formed at the side ends. And a guide plate 5 having a slide guide 7 which stands around the center of the upper surface and which holds a coil spring 8. Of course, a large number of probes 3 are electrically connected.

In the short package 1, the guide hole 4 is fitted into the slide guide 7, and the pressing plate 2
Is mounted on the IC 11 in a state where the probe 3 is assembled with the guide plate 5, and the pressing plate 2 is pressed to bring the probe 3 into contact with the respective pins 12. That is, the short package 1 is put on the IC 11 mounted on the IC mounting board, and
The circuit of the C mounting board is energized and the IC 11 covered with the short package 1 is placed at the pin setting position.
Inspection of broken patterns and solder defects up to this point.

FIGS. 2 and 3 show a mechanism for collectively inspecting a plurality of ICs 11 on a target printed board 21. FIG.

In this example, a plurality of short packages 1 having different sizes are prepared in accordance with the respective ICs 11 mounted on the IC mounting board 21, and a holding board 22 having a size corresponding to the IC mounting board 21 is prepared. And IC11
And are arranged equally.

When checking the IC 11, each I
Press C11 one by one with the short package 1,
Short between all pins 12 of C11. That is, a short check is sequentially performed between the two pins 12 of the IC 11 with the short package 1 covered.
In this way, it is sufficient to confirm that there is no broken pattern and no solder failure from the pin setting position to the IC 11.
The pressurizing operation of the short package 1 can be easily automated using a solenoid or the like.

FIGS. 4 to 6 show the main parts of an IC mounting board to be inspected. For example, pads between IC-A and IC-B and between IC-A 'and IC-B' are pad to pad.
Are connected by 1 to 5 are pins of the IC 11. At the time of inspection, IC1
A test pattern is transferred from the main body of the in-circuit tester between pins 1 to 5, and the conduction state is checked.
In such a case, a failure location mainly includes a broken pattern or a defective solder from the pin stand position to the IC.

More specifically, as shown in FIG.
Is pressed by the short package 1, and the pattern (1PA), the solder portion (1HA), the short portion of the short package 1, the solder portion (2HA), and the pattern (2) are taken from the 1-pin probing point (the position where the probe 3 stands).
PA) Measure resistance between 2 pin probing points. At this time, if defective, 1PA, 1HA, 2H
It can be seen that either A or 2PA is defective.

Similarly, 1 and 3, 1 and 4, 1 and n,...
The resistance is measured between 1 and 100. As a result, it is possible to determine the location of the error due to the change in the resistance, and it is possible to determine from which pin setting position the pattern to the IC is broken or a solder failure.

FIG. 8 is a flowchart for explaining the inspection process of the entire IC mounting board 21.

First, a description will be given of a case where a step of inspecting a solder defect of an IC covered with a short-circuit package and a circuit pattern up to the IC after performing a procedure for judging acceptability by an in-circuit tester.

That is, the in-circuit tester performs a check between connectors except for a pattern check between ICs in an open test, performs a short test on all nets, checks for a short circuit or a bridge, and performs an analog test for a resistor or a resistor. I for capacitors
The mounted components other than C are checked, and finally an IC test is performed.

When the above inspection is completed and OK is determined, the inspection ends.

If the determination result is NO, the IC-A is covered with the short package 1, and all pins are short-circuited. That is, when the short program is applied to the IC-A, from one pattern to the next pattern via the solder part, the short package 1, and the solder part,
A loop is formed between the patterns, and the conduction between the patterns is checked. If the result of the determination is OK, the IC-A is defective.
End the inspection.

Further, if the determination result is NO, the conduction state between the patterns from one pattern to the next pattern via the solder portion, the short package 1, and the solder portion is checked, so that which pin It turns out that the pattern has run out. Then, for example, the fact that three pins are out of pattern (poor contact) is printed, and the inspection is terminated.

Next, referring to FIG. 9, the process of inspecting the solder defect of the IC covered with the short package of the present invention and the circuit pattern up to the IC is automated, and after the short test in the procedure of judging pass / fail by the in-circuit tester. A description will be given of a case where a step of inspecting a circuit pattern up to an IC covered with a short package of the present invention is inserted and performed.

That is, the in-circuit tester performs a check between connectors except for a pattern check between ICs in an open test, and performs a short test on all nets to check for a short circuit or a bridge in the pattern.

In a specific IC for which a pattern check and a solder failure are to be tested, each IC below IC-A
11 is sequentially covered with the short package 1, and each IC 11
Are shorted at the shoulder 12 '. For example, if a short program is applied to the IC-A, and if the determination result is NO, the continuity between the patterns is checked and it can be determined which pin is disconnected. (Poor contact) is printed and the inspection is terminated.

In this embodiment, when the IC 11 is not defective, a broken pattern or a defective solder from the pin stand position to the IC can be easily detected, and the inspection can be performed quickly without the troublesome work in the IC test. .

[0032]

According to the method of inspecting an IC mounting board of the present invention, as described above, in the step of inspecting an IC, inspection of a conduction state such as a broken pattern or a solder defect from a pin stand position to the IC, which has been conventionally difficult, is performed. Since the process is added, it is possible to check for defects in the continuity state between the pins without replacing the IC, thereby greatly shortening the inspection time of the IC mounting board.

Further, it is not necessary to increase the number of pins of the tester main body for performing the pattern check as in the past.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a short-circuit package used in an IC mounting board inspection method according to the present invention.

FIG. 2 is a perspective view showing another example.

FIG. 3 is a perspective view showing a case where the present invention is applied to all ICs.

FIG. 4 is a plan view showing a main part of an IC mounting board to be inspected.

FIG. 5 is a perspective view thereof.

FIG. 6 is an enlarged perspective view of a main part.

FIG. 7 is a schematic diagram showing the details.

FIG. 8 is a flowchart showing an embodiment of a method for inspecting an IC mounting board according to the present invention.

FIG. 9 is a flowchart showing another embodiment of the method for inspecting an IC mounting board according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Short package 2 Press plate 3 Probe 4 Guide hole 5 Guide plate 6 Through hole 7 Slide guide 8 Coil spring 11 IC 12 pin 21 IC mounting board 22 Holding board

Claims (2)

[Claims] 1. A method of inspecting an IC mounted on an IC mounting board, wherein a step of inspecting a pattern break and a solder defect between pin standing positions of the IC is added to the step of inspecting the IC. Inspection method for IC mounting board. 2. The IC mounting board according to claim 1, wherein the means for inspecting a broken pattern and a solder defect between pin standing positions of the IC includes a plurality of probes, and is a short-circuit package in which the probes are electrically connected. Inspection method.