JPS5856834B2 - Contact state detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting a contact state between an electronic component such as a semiconductor device and a measurement head.

When performing a characteristic test on a semiconductor device such as an integrated circuit device IC, it is necessary to check the contact state between the external terminal of the object to be measured and the measurement terminal of a measurement head such as a socket before starting the test.

As the above-mentioned contact state detection method, a method is usually used in which a DC current is passed between input and output terminals and the voltage and current values at that time are measured to determine whether the contact is good or bad.

Such a DC method can be easily implemented using a test device having a DC characteristic measurement function.

However, in the case of dedicated testing equipment for AC characteristics, it is necessary to add a DC characteristics measurement function to detect the contact state using this method, which not only complicates the configuration of the measuring equipment and increases equipment costs, but also Adding a DC section unrelated to the measurement of the characteristics of the AC characteristics test equipment will lead to a decrease in the performance of the AC characteristics test device.

An object of the present invention is to solve the above-mentioned problems and provide an AC contact state detection method that does not require a DC characteristic measurement function.

The feature of the present invention is to detect the rise time and fall time of the pulse waveform when the object to be measured is attached to the measurement head and the output pulse of the pulse generator is applied to each terminal. The purpose of this is to determine whether the contact state of each terminal is good or bad.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of main parts showing an embodiment of the contact state detection method according to the present invention, and in this actual case, an example will be explained in which the contact state is determined using an automatic IC AC characteristic measuring device. do.

In the figure, 1 is the IC of the object to be measured, 2 is the measurement head on which the object to be measured is attached, 3 is the controller, 4 is the measurement unit for AC characteristics, and 5 is the T-T for converting time (1) into electric mV'll. V
A conversion circuit (TVC), 6 a comparison circuit, 7 a pulse generator, 8 a pattern generator, all of which are pulse generators, and 9 a multiplexer.

Note that the TVC 5 and comparison circuit 6 mentioned above are those normally included in an automatic AC characteristic measuring device.

Prior to the AC characteristic test, before the object to be measured is attached to the measuring head 2, a pulse signal as shown in FIG. is applied, and the rise time (or fall time) of the pulse is measured by the measurement unit 4 at the terminal portion of the measurement head 2, and the value is stored for each terminal.

The above measurement function is included in the AC characteristic automatic measurement device, so it is sufficient to use it, and there is no need to add a measurement circuit.

Next, the measuring head 2 mounts the IC 1 to be measured, and repeats the same operation as before based on the command from the controller 3 to measure the rise time of each terminal.

Fig. 3 is a diagram showing the rise characteristics at the terminal section of the measuring head 2 when the pulse shown in Fig. 2 is applied.The solid line is the rise characteristic when no object to be measured is attached, that is, the rise characteristic peculiar to the measurement system, and the broken line is indicates the rise characteristic when the object to be measured is attached.

As seen in the figure, the rise characteristics when the object to be measured is attached are worse than the rise characteristics inherent to the measurement system.

The present invention attempts to detect a contact state by utilizing this.

Therefore, the peak value v1 of the pulse voltage and the potential V when no pulse is applied.

The difference between [Vl-V.

] For example, the values V and vB of 10 [%] and 90 groups are determined.

Then, the time required for the pulse to reach VB from vA is measured when the object to be measured is not attached and when it is attached.

Let these times be tr and tr', respectively.

Specifically, the measurement of the rise time mentioned above is the measurement of the above tr, tr.
' G is measured.

That is, based on a command from the controller 3, the measurement unit 4 first measures tr, and the TVC 5 converts it into a voltage Vr corresponding to tδ, which is further stored in a register (not shown) provided in the comparison circuit 6.

This operation is performed for all terminals by activating the multiplexer 9 in response to a command from the controller 3.

Next, tr' is similarly measured for each terminal, converted to Vr', and compared with the Vr' by the comparator circuit 6 to obtain (Vr'-V
It is checked whether r'l is larger than a predetermined value Δvo.

As mentioned above, when the IC1 is attached to the measurement head 2, the rise characteristics deteriorate and tr>tr, that is, Vr'>Vr, but if the contact between the terminals is insufficient, the terminal will appear to be open at the top. tr”: tr or Vr”:;Vr
becomes.

Therefore, if Vr'-Vr≧Δvo, the comparison circuit 6 receives a signal, for example, signal [1], which indicates that the contact state is good.
Vr'Vr <If Δvo, a signal indicating poor contact condition] is sent to the controller 3 for each terminal.

The controller 3 sends out a control signal to proceed with a predetermined test when all the terminals are in a good contact state.

However, if even one terminal is in a bad contact state, the controller 3 stops the test and displays a contact failure.

As mentioned above, in this actual case, without adding a DC characteristic measurement function to the automatic AC characteristic measurement device, we can automatically detect whether the contact condition is good or bad by adding the measurement of the rise characteristic before measuring the AC characteristic. was completed.

It is easy to understand that in order to add the measurement of the rise characteristic described above, it is only necessary to partially change the program for proceeding with the measurement of the AC characteristic.

The present invention can be implemented by further modifying the actual case described above.

That is, in the above-mentioned actual case, the above-mentioned Vr)Vr' is the comparator circuit 6.
However, the present invention is not limited to this, and Vr and Vr' may be directly sent to the controller 3 and compared.In short, tr and tr
' may be compared for each terminal by some means, and there is no need to limit the means.

Therefore, the rising characteristic i"i= t r ' unique to the measurement system is measured in advance and stored in the controller 3, etc., and the rest is t
The present invention can also be practiced by measuring only r' and comparing it with stored tr.

Furthermore, in the case of a manual measuring instrument rather than an automatic measuring instrument, the present invention can be carried out by measuring and comparing the above-mentioned tr and tr' using a synchro scope or the like normally provided in the measuring section.

As explained above, according to the present invention, the contact state between the measurement head and the terminal of the object to be measured can be detected prior to measurement by simply changing the measurement procedure without making any changes to the AC characteristics measurement device. .

Therefore, measurement errors due to poor contact do not occur, and the reliability of measurement is improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of main parts showing the configuration of a system used in an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing the principle of the present invention. In the figure, 1 is an object to be measured, 2 is a measurement head, 3 is a controller, 4 is a measurement section, and 7 and 8 are pulse generators.

Claims (1)

[Claims] 1. Before testing the electrical characteristics of a measured object using a measuring device equipped with a pulse generator, the pulse generated when the measured object is attached to the measuring head and the output pulse of the pulse generator is applied to each terminal. A contact state detection method characterized by determining whether the contact state of each terminal is good or bad by detecting either the rise time or the fall time of a waveform.