JPH0370838B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a measuring device that connects a plurality of measuring instruments and an object to be measured via a switch matrix, and is used to measure multiple items that require signal transmission systems with different characteristics. It is suitable for

Although the field of application of the present invention is not limited to this, for example, in the field of research and development of semiconductor devices, quality control on manufacturing lines, etc., it is possible to measure the capacitance between arbitrary terminals of a semiconductor device on a wafer, etc. When a voltage is applied to a certain terminal, it is often necessary to measure the small current flowing through the same terminal or another terminal. Since these measurements are usually performed on a plurality of pairs of terminals, it is extremely uneconomical to provide a dedicated measuring device for each terminal because the required number of measuring devices increases. For this reason, a switch matrix is provided between the measuring instrument group and the plurality of terminals of the semiconductor element to switch the connections therebetween.

Now, since it is not possible to arrange the measuring instrument group and the semiconductor element in close contact with each other, the problem is where to provide the switch matrix between them.
One method is to extend the transmission path (in this case, a cable) from each measuring device to the vicinity of the semiconductor element, and install a switch matrix here to connect each channel connected to each terminal of the semiconductor. A switched connection may also be used. However, the switch matrix is usually composed of relays and the like, and is quite large. Therefore, the presence of such a large switch matrix is not desirable when using a manual prober, which is often used to obtain connections with semiconductor devices in measurements that require high resolution.

In order to avoid the above-mentioned problem, it is also possible to provide a switch matrix near the measuring instruments group and to connect this switch matrix and each of the above-mentioned channels by one system of cables. However, this method causes the following problems regarding the cables connecting the switch matrix and each channel.

Characteristics particularly required of a cable through which a signal for measuring minute currents passes are, for example, particularly low noise and high insulation.

On the other hand, cables that carry signals for capacitance measurement are required to have particularly good AC characteristics.

However, since there is no cable that provides both of these functions, the above-described configuration requires sacrificing the performance of either capacitance measurement or minute current measurement.

The present invention solves the above-mentioned problems and provides a measuring device that does not degrade the performance of any measurement item even though the switch matrix and each channel are connected through transmission paths such as cables. The purpose is to In order to achieve this purpose, the present invention provides a plurality of transmission paths connecting the switch matrix and each channel, and further provides a switch for selectively connecting the plurality of transmission paths to each channel. There is. According to this configuration, most of the switching of connections between the measuring instrument group and each channel is performed by a switch matrix separate from the channel section. Therefore, only a small amount of switches are required in the channel section, resulting in a small size. Furthermore, since a plurality of transmission paths are provided between the switch matrix and each channel, the optimum transmission path can be used depending on the type of measurement signal. Note that the term "measuring instrument" is used here in a broad sense, including voltage sources and current sources.

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic block diagram of a measuring device capable of measuring capacitance and minute current according to the present invention. In Figure 1, 1 is a high frequency constant voltage source, 2
is an ammeter, 3A and 3B are constant voltage sources, 4 is a microammeter, and F ₁ to F ₄ have characteristics suitable for microcurrent measurement (e.g., high insulation, low noise especially during vibration, and low dielectric absorption). Cables, C ₁ to C ₄ are cables with characteristics suitable for capacitance measurement (for example, good high frequency characteristics and small variations in various constants), S ₁₁ to S ₂₄ are constant voltage source 1, ammeter 2 and cable C ₁ ~
Switches for selectively connecting C ₄ , T ₁₁ to T ₃₄
are constant voltage sources 3A, 3B, micro current meter 4 and cables
5 is a switch matrix that _includes switches _{S 11 to} S ₂₄ and _{T 11 to T 34} ; (not shown), U ₁ to U ₄ are switches that selectively connect channels CH ₁ to CH 4, respectively, to cables F ₁ to F ₄ , and V ₁ to V ₄ are switches, respectively, for connecting channels CH 1 to CH ₄ , _respectively .
A switch for selectively connecting CH ₄ to cables C ₁ to C ₄ ; 6 a switch group including switches U ₁ to U ₄ and V ₁ to V ₄ ; and 7 a switch matrix 5.
and a control device that controls opening and closing of each switch in the switch group 6. The distance between the switch group 6 and the semiconductor device to be measured is configured to be as short as possible.

Note that in Figure 1, the cable connecting the measuring instrument and the channel is shown as one line for ease of viewing the drawing, but in reality, each cable has a core wire and is covered with a core wire so that it can be connected from the outside. It also has a guard wire to prevent it from being influenced by the guidance of other people. Furthermore, in order to avoid the effects of leakage resistance and stray capacitance in the switch portion, it is desirable to use a switch with a special structure for each switch in the switch matrix. An example of a connection between cables with guard wires and a switch used therein is given in the Utility Model Application Publication No. 1983-1999 entitled ``Matrix Switch.''
This is shown in the specification and drawings of No. 17021 (Utility Model Application Publication No. 57-131743).

A method for measuring capacitance and minute current using the measuring device shown in FIG. 1 will be explained below. Here, channels CH ₁ to CH ₄ are semiconductor elements on the wafer, such as FETs, transistors, diodes,
It is connected to various integrated circuits.

First, capacitance measurement will be explained. For example, when measuring the capacitance between the terminals connected between channels CH ₁ and CH ₂ , first
Channel CH ₁ and by closing V ₁ and V ₂
Cable C ₁ with characteristics suitable for capacitance measurement on CH ₂
and C ₂ respectively. Further switches S ₁₁ and S ₂₂
By closing the current meter 2, the current flowing between the channels CH ₁ and CH ₂ due to the high frequency voltage source 1 is detected.
It can be measured by From the relationship between the voltage of the voltage source 1 and the current value measured by the ammeter 2, the capacitance (and also the resistance component) between the terminals connected between the channels CH ₁ and CH ₂ is determined.

Next, measurement of minute current will be explained. For example, by applying voltage between channels CH ₁ and CH ₂ ,
When measuring a minute current such as MOSFET gate leakage current, first select the switches in switch group 6.
Channel CH ₁ and by closing U ₁ and U ₂
Connect CH ₂ to cables F ₁ and F ₂ , respectively, which have characteristics suitable for microcurrent measurements. Furthermore, by closing the switches _T11 and _T32 in the switch matrix 5, channels CH1 and _T32 are connected by the constant voltage source 3A.
A minute current flowing between CH ₂ is measured by a minute current meter 4. By separating the cables into those for capacitance measurement and minute current measurement, the measured value of minute current becomes stable in a short time after the switch is switched.

It is also possible to apply a voltage to a certain channel and measure the capacitance and minute current in other channels in that state. Other measurement items, such as inductance, can also be measured using the same measuring device. In this case, a cable with more preferable characteristics may be used, or another cable may be provided.

In the above description, the measurement of a semiconductor element was taken as an example, but the object to be measured is not limited to this, and the measurement items are, of course, not limited to those exemplified above.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a measuring device according to the present invention. 1: Constant voltage source, 2: Ammeter, 3A, 3B: Constant voltage source, 4: Micro ammeter, 5: Switch matrix, 6: Switch group, C ₁ to C ₄ : Cables with characteristics suitable for capacitance measurement , F ₁ to F ₄ : Cables with characteristics suitable for microcurrent measurement, CH ₁ to F 4
CH ₄ : Channel.

Claims (1)

[Scope of Claims] 1. A plurality of channels each connected to a terminal of an object to be measured, a plurality of transmission paths connected to the plurality of channels, a plurality of measuring instruments, and the plurality of measuring instruments and the plurality of measuring instruments. a switch matrix that selectively connects the transmission path of the switch matrix, and measures any one of the plurality of measurement items on any terminal of the object to be measured by switching the connection of the switch matrix. In the apparatus, a plurality of transmission paths having mutually different electrical characteristics are provided between each of the plurality of channels and the switch matrix, and a channel corresponding to the plurality of transmission paths having mutually different electrical characteristics is selected. A multi-item measuring device characterized by providing a group of switches that are connected to each other.