JPH07249669A - Semiconductor tester - Google Patents

Abstract

PURPOSE:To stabilize temperature environments to accurately evaluate characteristics by removing temperature variations inside a wiring TED tester. CONSTITUTION:A sputter film made of aluminum is formed on a semiconductor substrate coated with an insulation film etc., and dry-etched with the use of photoresist as a mask to form a turn-up wire TEG 5 made of aluminum. A power supply pad 8 and a power supply pad 9 formed with aluminum are disposed at both ends of the wires. At the same time, the turn-up wire made of aluminum is formed as a resistor 4 around the wiring TEG 5 in the same manner that wire intervals are equal to those of the wire TEG 5. A power supply pad 6 and a power supply pad 7 formed with aluminum are formed at both ends of the resistor 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor tester for testing and evaluating semiconductor products.

[0002]

2. Description of the Related Art A semiconductor TEG test apparatus is used to evaluate a semiconductor process and to test and evaluate reliability.

As an example, a test apparatus for a wiring TEG will be described below with reference to the drawings.

FIG. 2 is a plan view of a conventional semiconductor wiring TEG testing apparatus. In FIG. 2, 1 is a wiring TEG formed on a semiconductor substrate, 2 is a power supply pad connected to the wiring TEG1, and 3 is another power supply pad connected to the wiring TEG1.

A method of testing the semiconductor wiring TEG1 will be described. First, a voltage source is connected to the power supply pads 2 and 3 and a voltage is applied to cause a current to flow through the wiring TEG1. The characteristics of electromigration can be evaluated by monitoring the current flowing through the wiring TEG1.

[0006] The test by such a TEG test device,
When performing the evaluation, the temperature of the TEG test device is the sum of the ambient environment temperature and the temperature rise generated by the wiring TEG1 during the test. The temperature of the TEG test device has a very large effect on the characteristics during the electromigration test and evaluation, and therefore the temperature control during the test and evaluation is very important.

[0007]

However, in the above structure, due to the Joule heat generated by the current flowing through the wiring resistance, the central wiring portion where the wiring is dense and the peripheral wiring portion where there is no wiring adjacent to the central wiring portion. In and, a temperature difference occurs due to the difference in the surrounding wiring environment. Therefore, the temperature of the entire wiring TEG1 is not uniform, and the wiring TEG1
It had a problem that it could not be evaluated correctly.

The present invention solves the above problems by wiring TEGs.
It is intended to provide a TEG test apparatus for evaluating electromigration of a semiconductor, which eliminates a temperature difference in the interior and enables accurate characteristic evaluation.

[0009]

In order to solve the above problems, a semiconductor test apparatus of the present invention is arranged in the vicinity of the device under test formed on a semiconductor substrate and the periphery of the device under test. The resistor is composed of a single or a plurality of resistors made of a conductive material, and the power source pad independent of the device under test is arranged at both ends of the resistor.

[0010]

According to the present invention, the temperature of the device under test can be controlled by applying a current to the resistor arranged around the device under test and utilizing Joule heat generation.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As one embodiment, a case where the present invention is applied to a TEG test apparatus for evaluating electromigration of semiconductor will be described with reference to the drawings.

FIG. 1 is a plan view of a TEG testing apparatus for semiconductor electromigration evaluation in this embodiment. In FIG. 1, 4 is a temperature control resistor (hereinafter simply referred to as resistor 4), 5 is a wiring TEG, 6 is a power supply pad for the resistor 4, 7 is a power supply pad for the other resistor 4, and 8 is a wiring T.
A power supply pad connected to EG5, and 9 is another power supply pad connected to the wiring TEG5.

First, a method of manufacturing the TEG testing device of the present invention will be briefly described. An aluminum sputtered film is formed on a semiconductor substrate covered with an insulating film and dry-etched using a photoresist as a mask to form a film thickness of 0.5 μm, width of 1.2 μm, and wiring length of 1200 μm.
The aluminum wiring TEG5 is formed. A power supply pad 8 and a power supply pad 9 made of aluminum are formed on both ends of the wiring. At the same time, the resistor 4 is made of aluminum and has a film thickness of 0.5 μm and a width of 1.2 μm.
The folded wiring having a wiring length of 1200 μm is formed around the wiring TEG5 at the same intervals as the wiring intervals of the wiring TEG5. A power supply pad 6 and a power supply pad 7 made of aluminum are formed on both ends of the resistor 4.

Next, a test method for applying the TEG test apparatus of the present invention to electromigration evaluation of aluminum wiring will be described. When + 1.8V is applied to the power supply pad 8 of the wiring TEG5 and 0V is applied to the power supply pad 9, a current of about 18 mA flows through the wiring TEG5, and the temperature inside the wiring rises by an average of about 20 ° C. due to Joule heat. When this semiconductor substrate was held at 180 ° C. and subjected to an electromigration test, when a current of 18 mA was applied, 50% of the samples were broken (MTTF: Meen Ti
me to failure) was 190 hours.

At this time, the average temperature of the wiring TEG5 is
The ambient temperature is 180 ° C, and the temperature rise of 20 ° C due to Joule heat generation is added to 200 ° C.
The temperature of the central wiring portion and the peripheral wiring portion of No. 5 has a temperature variation of about 5 ° C. due to the concentration and dissipation of heat depending on the presence or absence of adjacent wiring. MTTF by electromigration is proportional to exp (-ΔE / kT). From this, it is possible to estimate the MTTF of the aluminum wiring used in the integrated circuit in the actual usage state (maximum wiring temperature of 100 ° C.).

However, if the temperature of the portion broken by electromigration is inaccurate, MT at 100 ° C.
The estimate of TF will be inaccurate. For example, when the temperature of the cut part is 200 ° C, ΔE is generally 0.6 eV.
And the temperature acceleration coefficient from 200 ° C to 100 ° C is 5
Since it is 1.8, MTTF at 100 ° C. is 190
It can be estimated that the time will be 51.8 = 9842 hours. However, if the wire is disconnected near the center, which is 5 ° C higher than the outer peripheral wiring, the wiring temperature is 205 ° C
Since the acceleration coefficient of the temperature from to 100 ℃ is 60.4,
The wire breaks in 190 hours × 60.4 = 111476 hours, and an error of about 15% occurs in the estimated value of MTTF due to electromigration.

In the TEG testing apparatus according to the present invention, the above error can be suppressed by passing an appropriate current through the temperature controlling resistor 4. For example, by applying +1.8 V to the power supply pad 6 and applying 0 V to the power supply pad 7 to cause a current to flow in the same manner as the wiring TEG5, the temperatures of the wiring TEG5 and the resistor 4 become the same. Since the resistance 4 is adjacent to the outer periphery of the wiring TEG5, the temperature does not decrease, and the temperature of the wiring TEG5 becomes constant. As a result, there is no difference in temperature between the central wiring portion and the peripheral wiring portion of the wiring TEG5, and a stable temperature state during the test can be secured.

As described above, the electromigration resistance can be properly evaluated. In the case of the present embodiment, the current density of the wiring TEG5 and the resistor 4 during the test evaluation is
It is necessary to make the exothermic conditions the same so that the temperatures are the same.

As described above, according to the present embodiment, by providing the resistor 4, the temperature difference between the central wiring portion and the outer peripheral wiring portion of the wiring TEG 5 is eliminated, so that accurate electromigration evaluation can be performed. Although the voltage is applied to the power supply pad 6 in the first embodiment, current may be applied. Further, although the wiring TEG5 and the resistor 4 are formed of the same aluminum wiring in this embodiment, even if they are formed of different aluminum wirings or different conductive materials,
It is clear that the objects of the invention can be achieved.

[0020]

According to the present invention, the device under test and the periphery of the device under test are provided on the semiconductor substrate with one or a plurality of resistors made of a conductive material. The Joule heat that is generated can create a temperature environment similar to that of the central wiring part in the outer peripheral wiring part of the device under test, so that there is no temperature difference in the wiring of the device under test, and stable and accurate electromigration The evaluation result can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of a test apparatus for evaluating electromigration of a semiconductor according to an embodiment of the present invention.

FIG. 2 is a plan view of a conventional semiconductor wiring TEG testing device.

[Explanation of symbols]

 4 resistance 5 wiring TEG 6 to 9 power supply pad

Claims (1)

[Claims] 1. A device under test formed on a semiconductor substrate, and a single or a plurality of resistors made of a conductive material and arranged in proximity to the periphery of the device under test,
Moreover, a power supply pad independent of the device under test is arranged at both ends of the resistor, and the semiconductor test device is characterized in that: