Interconnection substrate, skew measurement method, and test apparatus

1. An interconnection substrate used in skew adjustment between output pins in a test apparatus, the test apparatus supplying a test signal to a device under test to test the device under test, the interconnection substrate comprising:

a first terminal coupled to a first output pin that outputs the test signal;

a second terminal coupled to a second output pin that outputs the test signal;

a first interconnection connecting the first terminal to a bonding node;

a second interconnection connecting the second terminal to the bonding node; and

a third interconnection connecting the bonding node to an output node, wherein

the first interconnection and the second interconnection have a length equal to each other.

2. The interconnection substrate according to claim 1 , wherein

the length of the first interconnection and the second interconnection is the minimum.

3. The interconnection substrate according to claim 1 , wherein

the test apparatus includes an input terminal connected to a timing measurement circuit operable to measure a transition timing of an applied signal, and

the output node is a third terminal coupled to the input terminal.

4. The interconnection substrate according to claim 1 , further comprising:

a timing measurement circuit operable to measure a transition timing of an applied signal, wherein

the output node is an input node of the timing measurement circuit.

5. The interconnection substrate according to claim 1 , wherein

the test signal outputted from the first output pin is a positive phase signal, and the test signal outputted from the second output pin is a negative phase signal.

6. A skew measurement method for measuring a skew between output pins in a test apparatus, the test apparatus supplying a test signal to a device under test to test the device under test, the skew measurement method comprising:

preparing an interconnection substrate that includes a first terminal, a second terminal, a first interconnection connecting the first terminal to a bonding node, a second interconnection connecting the second terminal to the bonding node and having a length equal to the first interconnection, and a third interconnection connecting the bonding node to an output node;

coupling a first output pin of the test apparatus to the first terminal of the interconnection substrate, where the first output pin outputs the test signal, and coupling a second output pin of the test apparatus to the second terminal of the interconnection substrate, where the second output pin outputs the test signal; and

measuring a skew between the first output pin and the second output pin by measuring a voltage of the output node relative to a reference voltage.

7. The skew measurement method according to claim 6 , wherein

the measuring a skew includes:

outputting the test signal from the first output pin while maintaining the second output pin to either a high level or a low level, and measuring a first timing at which the voltage of the output node matches a first reference voltage, where the first reference voltage is determined based on a relation between a level of the second output pin and a transition state of the test signal;

outputting the test signal from the second output pin while maintaining the first output pin to either a high level or a low level, and measuring a second timing at which the voltage of the output node matches a second reference voltage, where the second reference voltage is determined based on a relation between a level of the first output pin and the transition state of the test signal; and

measuring the skew from a difference between the first timing and the second timing.

8. The skew measurement method according to claim 6 , wherein

the first output pin outputs a positive phase signal of the test signal, and the second output pin outputs a negative phase signal of the test signal, and

the measuring a skew includes measuring the skew using a value of a spike voltage occurring at the output node.

9. A test apparatus for supplying a test signal to a device under test to test the device under test, the test apparatus comprising:

a first output pin and a second output pin that output the test signal;

a timing measurement circuit operable to measure a timing of an applied signal; and

an interconnection substrate including:

a first terminal coupled to the first output pin, a second terminal coupled to the second output pin, a first interconnection connecting the first terminal to a bonding node, a second interconnection connecting the second terminal to the bonding node and having a length equal to the first interconnection, and a third interconnection connecting the bonding node to an output node that is coupled to an input of the timing measurement circuit.