JPS6318933Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention supplies a test signal to the IC element under test and compares its output with an expected value to
Related to IC testers that test elements.

Conventionally, in this type of IC tester, a test signal is generally supplied from one test signal source to one IC element under test, and the output of that one IC element under test is checked to ensure that the correct output is obtained. I was testing whether it worked or not. However, in a functional test, for example, since it is relatively time-consuming, a common test signal is applied to a plurality of IC elements to be tested and their outputs are specifically determined.

In such a case, in order to match the input and output, conventionally, as shown in FIG. The outputs of the IC devices under test 15 and 16 are led to the comparators 21 and 22 in the IC tester 11 through connection lines 17 and 18, respectively, to determine their logic levels, and the determination results are The output was compared with the expected value to determine whether the correct output was obtained.

When the output impedance of the driver 12 is 50Ω, the connection lines 13 and 14 have a characteristic impedance of 100Ω. Therefore, the impedance seen from the driver 12 on the connection lines 13 and 14 side is 50Ω, and matching between the input and output is achieved. The input and output impedance of the tested IC elements 15 and 16 is 50Ω, and the connection lines 17 and 18 on the output side are
The characteristic impedance of the amplifier 8 is also set to 50 Ω, and the input impedance of the decision circuits, that is, the comparators 21 and 22, is also selected to be 50 Ω.

In this way, the two IC elements to be tested 15,
16 were tested at the same time. IC element under test 1
The input impedance of 5 and 16 is 50Ω,
Looking at the connection lines 13 and 14 on the input side from the IC elements 15 and 16 under test, the characteristic impedance of the connection lines 13 and 14 is 100Ω, resulting in impedance mismatch.

Therefore, a reflection occurs at the connection between the IC devices under test 15, 16 and the input connection lines 13, 14, which returns to the driver 12, but the connection line 1
If the lengths of 3 and 14 are the same, there will be no effect because the same reflections will reach the output side of the driver 12 at the same time, and the operation will be the same whether there is one connection line or two connection lines. are doing. However, in this way, the lengths of the connecting lines 13 and 14 are not necessarily the same,
For this reason, the reflected waves generated at the input points of the IC elements 15 and 16 under test returned to the driver 12 side, sometimes affecting the output of the driver 12. It is reflected again at the output side of the driver 12 and sent to the test object again through the input connection lines 13 and 14.
The light reaches the IC elements 15 and 16 and is reflected back to the input side repeatedly, leading to the risk of so-called multiple reflections.

The purpose of this invention is to test two items as necessary.
The purpose is to supply the same signal to IC elements, and to enable accurate testing without affecting the test signal supply.

Below is a second example of an IC tester based on this invention.
Let me explain with reference to the diagram. In FIG. 2, a test signal is supplied from a driver 12 in an IC tester 11 to IC devices under test 15 and 16, and the characteristic impedance of connection lines 13 and 14 is adjusted to match the output impedance of the driver 12. The value is the impedance multiplied by the number of connection lines (2). For example, when the output impedance of the driver 12 is 50Ω, the connection lines 13 and 14 each have a characteristic impedance of 100Ω.

In this embodiment, terminal elements 26, 27 having an impedance equal to the characteristic impedance of the connecting lines 13, 14 are provided at the input connecting portions 24, 25 where the connecting lines 13, 14 are connected to the IC elements 15, 16 under test. Connected. In this example, the input connections 24 and 25 are connected to the termination elements 26 and 27 through connection lines 28 and 29 having a characteristic impedance of 100Ω.
is connected.

Furthermore, in this example, the IC device under test 15,
16 output connections 35 and 36 to comparators 21 and 22
In this example, the output connection lines 17 and 18 are connected to each other with the impedance of 50Ω.
In this embodiment, it has the same characteristic impedance as the input connection line 13, i.e. 100Ω in this example.
The parallel connection of the output connection lines 31 and 32 with a characteristic impedance of
7, 18.

Furthermore, in this embodiment, these connection lines 1
3, 14, 28, 29, 31, 32, 33, 34
is provided on the common board 37 and the IC under test
Input connection lines 13 and 28 are connected to input connection portions 24 of elements 15 and 16, respectively, and one ends of connection lines 14 and 29 are connected to input connection portion 25. Further, one ends of the connection lines 31 and 32 are connected to the output connection part 35 of the IC element under test 15, one ends of the connection lines 33 and 34 are connected to the output connection part 36 of the IC element under test 16, and ,32,33,3
4 are connected to each other at their other ends, and are connected to one input side of comparators 21 and 22, respectively. Furthermore, the other ends of the input connection lines 13 and 14 are connected to the output side of the driver 12, and the connection lines 28 and 29
Terminal elements 26 and 27 are connected to each other end of the terminal. The impedance of the termination elements 26 and 27 is the characteristic impedance of the connection lines 28 and 29, which is 100Ω in this example.

Depending on the IC elements 15 and 16 to be tested, the relationship between their terminal pins and input/output is different. Since the connection line is provided on the board 37, the connection parts 24, 25, 3
Connecting wires 13, 14, 28, 29, 3 to 5, 36
1, 32, 33, and 34 are connected to each other, and these connection lines are connected to the driver 12 and the judgment circuits 21 and 2.
2. Furthermore, which of the termination elements 26 and 27 to connect to is determined according to the input/output positional relationship of the pins of the IC element to be tested.

Because of this configuration, IC tester 11
In this example, the impedance seen from the driver 12 on the connection lines 13 and 14 side is matched with the output impedance of the driver 12, and moreover, the impedance at the input terminals of the IC elements 15 and 16 under test, that is, the input connection portion 24 , 25, the connection wires 13 and 28 are connected in parallel with respect to the input connection portion 24, and in this example, the impedance is 50Ω, ensuring impedance matching. Connecting wire 1 from end 25
Impedance matching can also be achieved when looking at the 4 and 29 sides. Further, the test signal from the driver 12 is supplied to the IC element 15 under test through the connection line 13, but even if reflection occurs at the connection part 24, it is absorbed at the termination element 26 side through the connection line 28, so that multiple reflections do not occur. Even if the lengths of the connecting lines 13 and 14 are different, and even if the test signal from the driver 12 is reflected at the terminal connections 24 and 25, it is absorbed by the terminating elements 26 and 27, and these terminating elements is reflected again to driver 1.
Even if it returns to 2, the level will be very small and there is no possibility of it affecting the output test signal.

When the connection wires are provided on the board 37 and each connection wire is a set of two as in the embodiment shown in FIG. Even if the IC tester and connection wire 1
3, 14, 28 to 34 can be freely selected, and in that case impedance matching can be performed on the input side and the output side.

If a test is performed to measure the input impedance of the IC elements 15 and 16 under test when the termination elements 26 and 27 are connected in this manner, it will not be possible to perform the test correctly due to the influence of these termination elements. Therefore, as shown in the figure, the input connections 24, 25
Switches 38 and 3 are connected between the terminal elements 26 and 27.
9 and turn off the switches 33 and 38 to measure the impedance.

Furthermore, the minimum value for the driver 12 is, for example, -2V.
If you connect the termination element as in the previous example when the output can only be output up to
Only a minimum signal of -1V can be supplied to the IC element 15. Also, although one end of the connection of these termination elements is grounded in the diagram, a large current may flow from the driver 12 to the termination element due to this relationship, and it is preferable for an IC tester to have such a large current flow. do not have.
In other words, not only does current consumption increase, but there is a risk that the driver 12 will become saturated and will not operate correctly. From this point of view, for example, as partially shown in FIG. 3, the termination element 26 is connected to one end of the connection line 28, and the other end is connected to the power supply 41, and the voltage of this power supply 41 is selected to perform the above procedure. Ensure that excessive current such as
A bias is applied to the IC device so as to provide a test signal of a desired level. If the power source 41 is connected, there is a risk that high frequency alternating current noise will be introduced thereto, so a noise removal capacitor 42 is connected in parallel with the power source 41.

This invention can be applied, for example, to a heated environment test device, a so-called handler device, for IC devices under test. rather than the IC handler's IC
It comes into contact with. Further, as for the output connection portion, impedance matching may be achieved using a single connection line without providing a plurality of connection lines.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the connection state between a conventional IC tester and the input/output section of the IC element under test, Figure 2 is a diagram of the connection between the IC tester and the IC element under test, and Figure 3 is a diagram showing an example of the IC tester according to this invention. is a diagram showing another example of a part thereof. 11: IC tester, 12: Driver, 13,
14: Input connection line, 15, 16: IC element under test, 24, 25: Input connection section, 28, 29: Connection line, 31, 32, 33, 34: Output connection line, 3
5, 36: Output connection part, 26, 27: Termination element,
21, 22: Comparison circuit for determination.

Claims (1)

[Scope of utility model registration request] One end of each of the two connection lines is connected to a test signal source that generates a test signal, the characteristic impedance of these connection lines is selected to be twice the output impedance of the test signal source, and the other end of each of these connection lines is It is connected to the input connection portions to be connected to the input terminals of the two devices under test, and these two input connection portions are connected to the input connection portions through the connection wires having the characteristic impedance described above. An IC tester in which each impedance termination element is connected.