JPH0488647A - Inspection substrate and method and device for circuit board inspecting - Google Patents

Abstract

PURPOSE:To make it possible to inspect simply a high-density circuit board and to improve the reliability of the circuit board by a method wherein the title substrate is provided with a plurality of pieces of voltage applying earthed circuits, which are capable of applying a voltage to the output terminals of inspection substrates and are capable of making the output terminals earth. CONSTITUTION:A circuit board 101 to be inspected is pinched by two sheets of inspection substrates 102, is aligned to the substrates 2, is pressure-welded to the substrates 2 and each land 106 to be measured on the substrate 101 is brought into contact to each probe terminal 103 on the substrates 102. Then, a voltage is generated in one terminal 103 of the inspection substrate by a voltage applying earthed circuit 104 on the basis of a command from an inspection signal generator 109 and at the same time, other terminals 103 are earthed in order by other voltage applying earthed circuits 104 and a current which is made to flow through the terminals is measured. This measured result is compared with a previously set value by the device 109 and whether the result is narmal or not is decided. When this inspection is executed for all the terminals 103, the inspection is completed. Thereby, an inspection of the high-density and large-scale circuit board is simply made possible and with the reliability of the circuit board improved, an inspection cost can be sharply reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for testing circuit boards such as semiconductor wafers and multilayer I&boards, to testing boards, and to 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 not uncommon for there to be over 1,000 lands on a single board. In addition, the gaps between the lands have become clogged, making it even impossible to stand the probe up for inspection. In the case of semiconductor wafers, probes are only partially erected at present.

Means for Solving IIB In order to solve such problems, the present invention has a plurality of voltage application grounding circuits that can apply voltage to the output terminal and ground the output terminal, and connect the output terminal to the probe terminal. There is a test board made of a semiconductor wafer, and the probe terminals are pressed into contact with the lands to be measured on the circuit board to be tested, and each voltage application grounding circuit is activated to apply a voltage to the designated probe terminals. The circuit board to be tested is tested by sequentially grounding the probe terminals and measuring the flowing tiJt.

Function Using the present invention, since terminals (pads and bumps) on a semiconductor wafer are used as probes, 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 and inspection 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 semiconductor wafer made of silicon, gallium arsenide, etc., which is simplified in FIG. The probe terminal 103 is arranged at the same position as the land to be measured on the circuit board to be tested, and contacts the land to be measured by pressing the probe terminal 103 into contact with the land to be measured. It is preferable to form a probe terminal with good conductivity and protrusions, such as a gold bump, as a probe terminal with good contact. Each probe terminal is an output terminal of a plurality of voltage applying ground circuits 104 formed on a semiconductor wafer. Each voltage application ground circuit receives a test signal (signal for testing) that enters the ground terminal 107.
It works by The connection terminal 107 is also a connection terminal for a test signal (information obtained from the circuit board to be tested) sent to the outside, a power supply, and the like. 108 is a test signal generator 1
09 and the test board 103. The test signal generator 109 operates the voltage application grounding 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 included),
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 application ground circuit generates a voltage at one probe terminal of the test board, while the other probe terminals are grounded one after another, and the flowing current is measured. This determination result is compared with a value set in advance by the test signal generator to determine whether it is normal or not. For all probe terminals,
Executing this test completes the test.

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.

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. The greater the number of probe terminals to be measured, the more difficult it becomes. In order to improve the contact, it is recommended to attach anisotropically conductive Ws (often used for drawing out terminals of liquid crystal display panels) to the surface of the probe terminals of the test board.

In addition, a pressure contact mechanism for positioning and pressing is required.

Even if the circuit board to be tested is a semiconductor wafer, where the land to be measured is only on one side of the board, there is no difference. Only one board is required for inspection.

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 on the circuit board to be tested 202, and each output probe terminal B of the voltage application grounding circuit 201 is brought into contact as shown in the figure.

The voltage application grounding circuit 201 is made up of two transistors, and causes current to flow from terminal A to output terminal B in accordance with a signal to signal terminal S, and also grounds output terminal B in accordance with a signal to signal terminal S.

This figure is omitted to explain the method.
Details such as signal voltage levels to signal terminals A and D are not considered, and the concept is merely expressed.

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 ends are all connected to terminal A of the voltage application grounding circuit. 2
04 is a decoder which sends a grounding signal to a designated voltage application grounding circuit using a grounding terminal designation code 207 to ground the designated output terminal B.

205 is also a decoder, which sends an application signal to a specified voltage application grounding circuit using an application terminal designation code 208, and connects a specified output terminal B to the 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 the output probe terminals B1 and 83 are grounded, and there is a voltage drop across the resistor 203, confirming that the wiring is properly connected. can. If there is a voltage drop at any other point, 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.

This testing method not only tests for continuity, but also measures the resistance value based on the magnitude of the voltage drop. You can also measure capacitance and inductance. In addition, although there is an extra voltage application grounding circuit in Figure 0, which can inspect leakage between probe terminals, stray capacitance, and inductance, it does not pose any problem for inspection.

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, even in a voltage application grounded circuit, the ability to flow current If you have the ability to inhale, you can perform your functions. In other words, even if there is some resistance, it can be compensated for later. Furthermore, some signal processing circuits may be mounted on the test board, thereby simplifying communication with the test signal generator.

Regarding the probe terminals on the test board, it was stated that they should be provided 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. Also, according to the position of the land to be measured on the circuit board to be tested, the semiconductor wafer
It is also possible to attach bumps only to those at the corresponding positions among the voltage application grounding circuits that are laid out all over the top. 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 above explanation, by using the present invention, it is possible to easily inspect high-density, large-scale circuit boards, which was difficult in the past, and the great performance of 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 tested, +02...Block/Test board, 103...Probe terminal, 10.4...Old voltage application grounding circuit, 105...Internal wiring ,
106...Land to be measured, 107...
Connection terminal, 108... Connection cable, 109.
206...Test signal generator, 201...
・Voltage application ground circuit, 202...Circuit board to be inspected, 203...Resistor, 204...Ground terminal designation decoder, 205...Voltage application terminal designation Decoder, 207... Ground terminal designation code,
208... Voltage application terminal designation code.

Claims (8)

[Claims] (1) There is a test board made of a semiconductor wafer that has multiple voltage application grounding circuits that can apply voltage to output terminals and ground them, and uses the output terminals as probe terminals. Press it into contact with the land to be measured on the circuit board, apply voltage to the designated probe terminal by activating each voltage application grounding circuit, ground the other probe terminals in sequence, measure the flowing current, and A circuit board inspection method for inspecting an inspection circuit board. (2) Inspect the circuit board to be tested by bringing the probe terminals of the two test boards on both sides into contact with the lands to be measured on both sides of the circuit board to be tested, and activating the voltage application grounding circuits on both boards to be tested. The circuit board inspection method according to claim (1), characterized in that: (3) A test board made of a semiconductor wafer, which has at least a plurality of voltage application grounding circuits capable of applying a voltage to or grounding an output terminal, and whose output terminals serve as probe terminals. (4) The test board according to claim (3), wherein a bump is provided on the output terminal of the voltage application grounding circuit and is used as a probe terminal. (5) Claim (5) characterized in that the probe terminal surface of the test board is covered with an anisotropically conductive elastic body 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 (4). (6) It has at least a plurality of voltage applying grounding circuits capable of applying voltage to the output terminals and grounding them, and includes a test board made of a semiconductor wafer whose output terminals are used as probe terminals, and a voltage applying grounding circuit. a test signal generator that operates in a predetermined manner to test connection relationships;
A circuit board testing device that includes a pressure contact mechanism that brings probe terminals on a test board into contact with lands to be measured on a circuit board to be tested. (7) The circuit board inspection apparatus according to claim (6), wherein the inspection board has a bump provided on the output terminal of the voltage application grounding circuit and uses the bump as a probe terminal. (8) From claim (6), characterized in that the probe terminal surface of the test board is covered with an anisotropically 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 (7).