JPH0485894A - Circuit board inspection method, inspection board, and circuit board inspection equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of testing a circuit board, a testing board, and a circuit board testing apparatus.

2. Description of the Related Art In the conventional circuit board testing method, a plurality of contact needles (probes) arranged on a board (probe card) are pressed against the circuit board to be tested, and the probes are placed on the land to be measured (tested land). The probe was brought into contact with patterned conductors, lands, etc. on the test circuit board, and signals were sent to and received from the probe to test whether the circuit board to be tested was properly formed.

Problems that inventions aim to solve However, recently, the miniaturization of devices has continued and there is no stopping point. In order to achieve miniaturization, extremely high-density packaging is being carried out, and it is becoming common to see more than one (100) lands on a single board.In addition, the pitch between the lands is also becoming narrower, making it difficult to stand the probes upright. It has even become impossible to carry out inspections.

Means for Solving the Problems In order to solve such problems, the present invention brings probe terminals on one side of a test board made of a multilayer wiring board into contact with lands to be measured on a circuit board to be tested. Then, apply a voltage to the land under test on the circuit board under test through the specified probe terminal by the voltage application ground circuit on the other side of the circuit board under test, and then contact the other land under test on the circuit board under test. The circuit board to be tested is tested by sequentially grounding the probe terminals and measuring the flowing current.

If the present invention is used, terminals (lands) on a multilayer board are used as probes, so even if the circuit board has a high density or there are many lands to be measured, it can be easily inspected.

Embodiment Hereinafter, an embodiment of the circuit board inspection method, inspection board, and circuit board inspection apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram of the principle of the circuit board inspection method of the present invention.

Lands to be measured (exterior wiring such as lands) 106 on the circuit board to be inspected 101 are connected by internal wiring 105 to other lands to be measured (exterior wiring such as lands) on the same surface or another surface. It is inspected whether the wiring condition of the circuit board to be inspected is as desired. Inspection board 1
02 is a multilayer wiring board, which is shown in a simplified manner in FIG.

The probe terminal 103 is located at the same position as the land to be measured on the circuit board to be tested, and comes into contact with the land to be measured by pressure contact. Each probe terminal is wired within the test board and connected to an application ground circuit 104. In the figure, one IC is representatively drawn.

108 is an inspection signal coming from the outside (signal for inspection)
It is a connection terminal for a detection signal (information obtained from the circuit board under test) to be sent to the outside, a power supply, etc. The application ground circuit and this connection terminal are connected by a wiring 107. A cable 109 connects the detection signal generator 110 and the test board 103. The test signal generator 110 operates the application ground circuit according to a preset program, processes information obtained from the circuit board to be tested thereby, and tests the circuit board to be tested.

A circuit board to be tested 101 is sandwiched between two test boards 103,
Align the positions and press them together (pressing mechanism is not shown).
Each land to be measured on the circuit board to be tested is brought into contact with each probe terminal on the board to be tested. In response to a command from the test signal generator, a voltage is generated at one probe terminal of the test board by an application grounding circuit, while other probe terminals are grounded one after another, and the flowing current is measured. This measurement result is compared with a value set in advance by the test signal generator to determine whether it is normal or not. The test is completed by performing this test on all probe terminals.

Continuity or resistance value testing can be performed by checking whether a desired current flows between desired probe terminals.

Furthermore, the leakage test may be performed by testing the current flowing through probe terminals other than the desired probe terminal.

The test substrate 102 may be a commonly used glass epoxy multilayer substrate or a ceramic multilayer substrate.

The application ground circuit may be made by combining individual components or may be an IC. Of course, it is also possible to use multiple ICs.

It is difficult to make contact between the land to be measured on the circuit board to be tested and the probe terminal on the board to be tested, and the more the number of probe terminals to be measured increases, the more difficult it becomes. To improve contact, it is best to apply an anisotropically conductive film (often used for connecting terminals of liquid crystal display panels) to the surface of the probe terminals on the test board. In addition, a pressure contact mechanism for positioning and pressing is required.

FIG. 2 is a specific example for more specifically explaining the inspection method of the present invention.

The probe terminal of the test board is brought into contact with the land to be measured of the circuit board to be tested 202, and each output probe terminal B of the application ground circuit 201 is connected as shown in the figure.

The voltage application grounding circuit 201 is made up of two wires, and connects the voltage from the power supply terminal A to the signal terminal S (S
It is transmitted to output terminal B according to the on/off current flowing through the current.

Further, the output terminal B is grounded by a signal to the signal terminal.

206 shows a part of the test signal generating device;
3 is a resistor for measuring current value. One end is connected to the power supply, and the other end is connected to the power supply terminal A of all applied ground circuits.

204 is a decoder, and with the ground terminal designation code 207,
Sends a grounding signal to the specified application grounding circuit and grounds the specified output terminal B. 205 is also a decoder, which sends an application signal to a specified application grounding circuit using an application terminal designation code 208, and connects a specified output terminal B to a power supply through a resistor 203.

An example of the inspection method is, for example, the application terminal designation code 208
A voltage is generated at the output terminal B1.

Next, using the grounding terminal designation code 207, the output probe terminals BO to B15 are grounded in sequence.

In the case of the wiring of the circuit board under test as shown in the figure, current flows only when output probe terminals B1 and 83 are grounded, and there is a voltage drop across resistor 203, confirming that the wiring is properly connected. . If there is a voltage drop in any other case, there is a short circuit, and you can discover the abnormality. If you do this process for all probe terminals (BO to 8
15], it can be seen whether the circuit board to be tested is manufactured normally.

With this testing method, you can not only test for continuity (but also measure the resistance value based on the magnitude of voltage drop). You can also measure capacitance and inductance. You can also test for inductance, leakage, etc. between probe terminals and stray capacitance. There is an extra grounding circuit, but it does not pose a problem for inspection. In the figure, a relay is used to make the operation of the grounding circuit easier to understand, but it is obvious that it can be done with semiconductors. This is more preferable because it allows XC and may require multiple probe terminals.

Although it is easy to imagine, the principles and specific examples shown are just examples, and there are many variations in circuit configuration, signal application method, etc. For example, a force-grounded circuit can function as long as it has the ability to source and sink current. That is, even if there is a small amount of resistance, it can be calculated and compensated for later. Furthermore, some signal processing circuits may be mounted on the test board, thereby simplifying communication with the test signal generator.

It is assumed that the probe terminals on the test board are located at positions corresponding to the lands to be measured on the circuit board to be tested.
There is no need for a one-on-one correspondence.

For example, it is also possible to arrange the probe terminals in a grid pattern that is finer than the shape of the land to be measured. In this case, it is not necessary to create a test board for each circuit board to be tested.

The test signal generating device may be something like a personal computer, or may be a dedicated device.

Effects of the Invention As is clear from the invention, by using the present invention, it is possible to easily inspect high-density, large-scale circuit boards, which was previously difficult, and the reliability of the circuit boards can be improved. However, inspection costs can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the principle of the circuit board testing method of the present invention, and FIG. 2 is a diagram illustrating the configuration and operation specifically explaining the circuit board testing method of the present invention. 101...Circuit board to be inspected, 102...
・Inspection board, 103...Probe terminal, 104
...... Application grounding circuit, 105... Internal wiring, 106... Land to be measured, 107...
... Wiring, 108... Ground terminal, 109...
... Connection cable, 110.206 ... Test signal generator, 201 ... Application grounding circuit, 20
2... Circuit board to be inspected, 203... Resistor, 204... Ground terminal designation decoder, 205
...Voltage application terminal designation decoder, 207...
...Grounding terminal designation code, 208...Voltage application terminal designation code.

Claims (10)

[Claims] (1) Contact the probe terminal on one side of the test board made of a multilayer wiring board to the land to be measured on the circuit board to be tested, and use the grounding circuit on the other side of the test board to A voltage is applied to the land under test on the circuit board under test through the probe terminal, while the probe terminals that contact other lands under test on the circuit board under test are grounded in sequence, the flowing current is measured, and the land under test is A circuit board inspection method for inspecting circuit boards. (2) Contact the test board from both sides of the circuit board to be tested,
2. The circuit board testing method according to claim 1, wherein the circuit to be tested is tested by making the application ground circuits on both test boards work together. (3) Probe terminals are provided on one side of the multilayer wiring board at positions corresponding to the lands to be measured on the circuit board under test, and application grounding is applied to the other side to apply voltage to or ground the specified probe terminals. An inspection board characterized by being provided with a circuit. (4) The test board according to claim (3), wherein the test board is a ceramic multilayer board. (5) The test board according to any one of claims (3) and (4), wherein the application grounding circuit is an IC. (6) The probe terminal surface of the test board is covered with an anisotropically conductive elastic material to facilitate contact between the land to be measured of the circuit board to be tested and the probe terminal of the test board (
The test board according to any one of 3) to (5). (7) At least, the circuit board is made of a multilayer wiring board, with probe terminals on one side for contacting lands under test on the circuit board under test, and on the other side, the specified probe terminals are passed through the circuit board under test. A test board that has a voltage application ground circuit that can apply voltage to or ground the land to be measured on the top, a test signal generator that operates the voltage application ground circuit in a predetermined manner to test the connection relationship, and a test board. A circuit board testing device having a press-contact mechanism for bringing each probe terminal on the top into contact with a corresponding terminal of a circuit board to be tested. (8) The circuit board testing device according to claim (7), wherein the testing board is a ceramic multilayer board. (9) The circuit board inspection apparatus according to claim 7 or 8, wherein the application ground circuit is an IC. (10) From claim (7), characterized in that the probe terminal surface of the test board is covered with an anisotropic conductive elastic material to facilitate contact between the probe terminals of the circuit board to be tested and the probe terminals of the test board. The circuit board inspection device according to any one of (9).