JPH0864651A - Method and apparatus for measuring temperature of micro wiring - Google Patents

Abstract

PURPOSE: To evaluate the lifetime of a wiring accurately by arranging the emitter-base junction of a transistor closely to the wiring and determining the temperature of the wiring from the variation of base-emitter voltage of the transistor when a constant current is fed thereto thereby measuring the temperature of the wiring accurately. CONSTITUTION: The emitter-base junction of a transistor is arranged closely to a wiring 6 for which the temperature is measured and the temperature of the wiring 6 is determined from the variation of base-emitter voltage of the transistor when a constant current is fed thereto. For example, a base region 2 and an emitter region 3 are formed in a substrate 1 and a transistor is constituted using the substrate 1 as a collector. Furthermore, the wiring 6 is patterned on the surface of the substrate 1 through a thin oxide insulation film 5 and the wiring 6 is stretched across the E-B junction 7 between the emitter region 3 and the base region 2. A constant current is then fed to the wiring 6 while applying the base region 2 with a voltage for turning the transistor ON.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine wiring temperature measuring method and apparatus for accurately measuring the temperature of a wiring formed on a substrate such as a semiconductor device in order to evaluate its life. .

[0002]

2. Description of the Related Art In a semiconductor device, a wiring such as Al is patterned on a field oxide film such as LOCOS. However, the current flowing through the wiring causes heat generation of the wiring itself to affect its life. There is electromigration in which a current corresponding to the cross-sectional area is applied and the life of the wiring is represented by the current density and the frequency such as temperature.

[0003]

In order to perform the above-described evaluation, conventionally, the temperature of the wiring is generally measured by an infrared monitor or the like, but the resolution of infrared wavelength is limited, Along with the recent miniaturization of wiring, there has been a problem that the temperature of fine wiring having a width of less than 1 μm cannot be independently measured. It is also possible to measure the change in resistance due to the temperature rise of each wiring, but the measurement error is large, for example, about 5%, which is not very realistic.

The present invention has been made in view of the problems of the prior art as described above, and its main purpose is to measure the temperature of an accurate wiring and thereby to precisely evaluate the life of the wiring. An object of the present invention is to provide a wiring temperature measuring method and apparatus.

[0005]

According to the present invention, there is provided a method for measuring a temperature of a fine wiring formed on a substrate due to self-heating, the method comprising: A method for measuring the temperature of a fine wiring, characterized in that the emitter-base junction of a transistor is arranged in close proximity, and the temperature of the wiring is obtained from a voltage change between the base-emitter of the transistor when a constant current is applied to the wiring. A device for measuring a temperature due to self-heating of fine wiring formed on a substrate, wherein the emitter-base junction is arranged below the wiring whose temperature is to be measured via an insulating film. A transistor formed on the substrate; and means for obtaining the temperature of the wiring from the voltage change between the emitter and base of the transistor when a constant current is applied to the wiring. It is achieved by providing a temperature measuring device of fine wiring to symptoms.

[0006]

The voltage between the base and emitter of the transistor changes with temperature. Therefore, by arranging the emitter-base junction (hereinafter, referred to as EB junction in this specification) of the transistor whose temperature has been calibrated in advance close to the wiring whose temperature is to be measured, the temperature change causes the base-emitter junction. The voltage changes. If the change amount ΔVBE is measured,
The temperature of the wiring is obtained from the calibration curve.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing the configuration of a temperature measuring device for fine wiring of a semiconductor device to which the present invention is applied. By introducing impurities into the substrate 1, for example, a base region 2 formed of an n-type active region and an emitter region 3 formed of a p-type active region are formed inside the base region 2, and thus the substrate 1 is formed. Is used as a collector to form a transistor. These base region 2 and emitter region 3
Are connected to a constant voltage source (not shown). Also,
A voltage measuring device 4 is connected between the base region 2 and the emitter region 3.

A thin oxide insulating film 5 is formed on the surface of the substrate 1, and a wiring 6 whose temperature is to be measured is patterned on the upper surface thereof. Here, the wiring 6 is extended along the EB junction 7 between the base region 2 and the emitter region 3 so as to straddle the same. The wiring 6 is connected to a constant current source (not shown). Here, the thinner the oxide insulating film 5 between the wiring 6 and the base region 2 and the emitter region 3, the better the thermal conductivity and the accurate temperature can be measured. Since it is feared that the emitter region 3 may be broken due to a potential difference between the emitter region 3 and the emitter region 3, the thickness is appropriately balanced.

The operating procedure of this embodiment will be described below. First, a bias Vb that turns on the transistor is applied to the base region 2 of the transistor having the base region 2 and the emitter region 3. Wiring 6 in that state
When a constant current is applied to the wiring 6, the temperature of the wiring 6 rises due to self-heating. Then, the EB junction 7 is heated, and the change amount ΔVBE of the voltage VBE between the base region 2 and the emitter region 3 changes as shown by the temperature calibration curve in FIG. This ΔVBE
Therefore, the temperature T of the wiring 6 is obtained. According to the actual measurement result, the error range of the temperature T at that time was within ± 0.5%. As a result, the life of the wiring 6 can be accurately evaluated.

In this embodiment, the EB joint 7 is connected to the wiring 6
Although the temperature is calculated to be substantially equal to, the temperature difference between the two should be corrected in practice.

[0011]

As is apparent from the above description, according to the temperature measuring method and apparatus for fine wiring of the present invention,
To measure the temperature due to self-heating of the fine wiring formed on the substrate, the emitter-base junction of the transistor is placed close to the wiring, and the voltage between the base and emitter of the transistor when a constant current is applied to the wiring. By determining the temperature of the wiring from the change, it is possible to accurately measure the temperature of the fine wiring above it by forming a transistor on the same scale as the fine wiring on the substrate under the wiring. Life evaluation can be performed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the configuration of a fine wiring temperature measuring device in a semiconductor device to which the present invention is applied.

FIG. 2 is a diagram showing the temperature of wiring on the substrate and the voltage V between base and emitter.
The graph which shows the relationship with the variation amount BE of BE.

[Explanation of symbols]

 1 substrate 2 base region 3 emitter region 4 voltage measuring device 5 oxide insulating film 6 wiring 7 EB junction

Claims (2)

[Claims] 1. A method for measuring a temperature due to self-heating of a fine wiring formed on a substrate, wherein a transistor emitter-connects to the wiring whose temperature is to be measured.
A method for measuring the temperature of a fine wiring, characterized in that the temperature of the wiring is obtained from the base-emitter voltage change when a constant current is applied to the wiring by arranging the base junctions close to each other. 2. An apparatus for measuring a temperature of a fine wiring formed on a substrate due to self-heating, wherein an emitter-base junction is disposed below the wiring whose temperature is to be measured, with an insulating film interposed therebetween. And a means for obtaining the temperature of the wiring from the voltage change between the emitter and the base of the transistor when a constant current is applied to the wiring. Temperature measuring device.