CN1982906A - Structure and method for testing metal interconnecting charge transfer - Google Patents

Abstract

The invention discloses a metal interconnection wire electromigration test structure, which includes a metal coil, an interconnection wire test structure and a temperature monitoring resistor, the interconnection wire test structure and the temperature monitoring resistor are both strip structures, and parallel to each other and arranged side by side, the metal coil surrounds the interconnection test structure and the temperature monitoring resistor. The invention also discloses a method for testing the electromigration of metal interconnection wires realized by the above-mentioned structure. Firstly, current is applied to the metal coil so that the temperature around the interconnection wire test structure reaches the set temperature, and then the interconnection wire test structure is energized to a constant temperature. current, and record the failure time. The evaluation of electromigration of metal interconnection wires in the present invention does not need to consume silicon wafers due to packaging and testing after dicing, thereby greatly reducing costs, shortening test time, improving test efficiency, and real-time monitoring of process changes. Effects of Electromigration in Metal Interconnects.

Description

Test Structure and Method for Electromigration of Metal Interconnect Lines

technical field

The invention relates to a test structure for reliability of semiconductor devices, in particular to a test structure for electromigration of metal interconnection lines. The invention also relates to a test method for electromigration of metal interconnection wires.

Background technique

Electromigration of metal interconnects is one of the main failure mechanisms in microelectronic devices. Electromigration causes open and short circuits of metal interconnects, which increases device leakage current. After the device size develops to sub-micron and deep sub-micron, the width of the metal interconnection is also continuously reduced, the current density is continuously increased, and it is more likely to fail due to electromigration. Therefore, with the progress of the process, the evaluation of the electromigration of metal interconnection wires has attracted much attention. However, the traditional electromigration evaluation method requires encapsulation and testing after dicing the sample, which consumes silicon wafers. During the evaluation process, an additional oven is used as a heating source to increase the ambient temperature, thereby increasing the evaluation cost, and from encapsulation to It took several weeks to complete the evaluation, which made it impossible for us to monitor the quality of the metal interconnection line in real time. Therefore, we urgently hope to obtain a fast metal interconnect electromigration evaluation structure, which can greatly improve the test efficiency on the premise of obtaining a fairly good consistency with the traditional packaging test results.

Contents of the invention

The technical problem to be solved by the present invention is to provide a metal interconnect electromigration test structure and method, which does not need to consume silicon wafers due to packaging and testing after scribing, and can shorten test time, improve test efficiency, and monitor in real time The effect of process variations on electromigration of metal interconnect lines at no additional cost.

In order to solve the above-mentioned technical problems, the technical scheme of the test structure for metal interconnection electromigration of the present invention is to include a metal coil, an interconnection test structure and a temperature monitoring resistor, and the interconnection test structure and the temperature monitoring resistor are both It is a strip structure, the interconnection test structure and the temperature monitoring resistor are arranged parallel to each other and side by side, and the metal coil surrounds the interconnection test structure and the temperature monitoring resistor.

The technical scheme of the testing method of metal interconnection electromigration of the present invention is, comprises the following steps:

(1) Measure the temperature resistance coefficient of the temperature monitoring resistor, and measure the initial resistance of the metal interconnection test structure, temperature monitoring resistor, and metal coil;

(2) Change the current of the metal coil;

(3) Monitor the resistance value change of the temperature monitoring resistor, and convert the resistance value change of the temperature monitoring resistor into a temperature change through the temperature resistance coefficient of the temperature monitoring resistor;

(4) judge whether to reach set temperature, if not reach, go to step (2);

(5) If the set temperature is reached, add a constant current to the interconnection test structure;

(6) Monitor the resistance change of the interconnection test structure, and record the time;

(7) Judging whether the failure criterion is reached, if not, go to step (6);

(8) If the failure criterion is met, output the failure time.

Through the above-mentioned structure and method, the present invention makes the evaluation of electromigration of metal interconnection wires unnecessary to consume silicon wafers due to encapsulation and testing after scribing, thereby greatly reducing costs, shortening test time, and improving test efficiency , which can monitor the effect of process variation on the electromigration of metal interconnect lines in real time.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment:

Fig. 1 is the schematic diagram of the test structure of electromigration of metal interconnection line of the present invention;

FIG. 2 is a flow chart of the test method for electromigration of metal interconnection wires according to the present invention.

Detailed ways

With the improvement of the integration level of modern integrated circuit chips, the length of the metal interconnection line and its interconnection level gradually increase, the line width of the metal interconnection line itself becomes narrower and narrower, and the current density passing through the metal line is also increasing , so such devices are more prone to electromigration. A fast and efficient metal interconnect electromigration evaluation structure can effectively monitor the reliability of the metal interconnect, and timely feedback the relevant situation to the production line, so as to strengthen the control of related process steps to obtain high quality and high reliability sex products.

The test structure of metal interconnection electromigration of the present invention is shown in Fig. 1, comprises metal coil 1, interconnection test structure 2 and temperature monitoring resistance 3, and described interconnection test structure 2 and described temperature monitoring resistance 3 are both It is a strip structure, the interconnection test structure 2 and the temperature monitoring resistor 3 are arranged parallel to each other and side by side, and the metal coil 1 surrounds the interconnection test structure 2 and the temperature monitoring resistor 3 . The metal coil 1 is in the shape of a "day", and the interconnection test structure 2 and the temperature monitoring resistor 3 are respectively located in two gaps in the metal coil. A node is arranged at a certain distance on the metal coil 1 , the distance may be 10 microns, so as to prevent electromigration of the metal coil for heating. The interconnect test structure 2 is a Kelvin structure resistance. The length of the interconnect test structure 2 is greater than 110 microns, and the width is between 6 microns and 8 microns. The metal interconnection electromigration test structure is on the metal layer of the semiconductor device. The metal coil 1, the interconnection test structure 2 and the temperature monitoring resistor 3 are made of the same material.

The method for testing the electromigration of metal interconnection wires realized by the present invention using the above structure includes the following steps:

(1) Measure the temperature resistance coefficient of the temperature monitoring resistor, and measure the initial resistance of the metal interconnection test structure, temperature monitoring resistor, and metal coil;

(2) Change the current of the metal coil;

(3) Monitor the resistance value change of the temperature monitoring resistor, and convert the resistance value change of the temperature monitoring resistor into a temperature change through the temperature resistance coefficient of the temperature monitoring resistor;

(4) judge whether to reach set temperature, if not reach, go to step (2);

(5) If the set temperature is reached, add a constant current to the interconnection test structure;

(6) Monitor the resistance change of the interconnection test structure, and record the time;

(7) Judging whether the failure criterion is reached, if not, go to step (6);

(8) If the failure criterion is met, output the failure time.

The present invention adds a circle of metal coils around the metal interconnection test structure through the above structure, and passes a certain current to the metal coils. Since the thermal resistance coefficient of metals is low, most of the power added to the metal coils is less than The form of heat is dissipated into the environment, so as to achieve the effect of increasing the ambient temperature of the metal interconnection test structure. Its effect is equivalent to the effect of the oven in the traditional method, but it can provide an ambient temperature much higher than that provided by the oven, so that It can accelerate the occurrence of electromigration of metal interconnection lines and shorten the evaluation time. The test structure and method of the present invention can be used to quickly evaluate the electromigration of metal interconnection lines on a semiconductor parameter tester, and the time it takes is usually tens of seconds, and the results obtained are quite consistent with those of traditional packaging tests. sex. At the same time, the structure can be placed in the dicing groove and tested together with ordinary electrical parameters without dicing and packaging, which can effectively save costs and can monitor the impact of changes in the production process on metal electromigration in real time.

Claims (9)

1. the test structure of a metal interconnecting charge transfer, it is characterized in that, comprise wire coil, interconnection line test structure and monitoring temperature resistance, described interconnection line test structure and described monitoring temperature resistance are list structure, described interconnection line test structure and described monitoring temperature resistance are parallel to each other and are arranged side by side, and described wire coil is enclosed in around described interconnection line test structure and the described monitoring temperature resistance.

2. the test structure of metal interconnecting charge transfer according to claim 1 is characterized in that, described wire coil is " day " font, and described interconnection line test structure and monitoring temperature resistance lay respectively in two interior spaces of wire coil.

3. the test structure of metal interconnecting charge transfer according to claim 1 is characterized in that, is provided with a node every a segment distance on the described wire coil.

4. the test structure of metal interconnecting charge transfer according to claim 1 is characterized in that, is provided with a node every 10 microns on the described wire coil.

5. the test structure of metal interconnecting charge transfer according to claim 1 is characterized in that, described interconnection line test structure is the resistance of Kelvin's structure.

6. the test structure of metal interconnecting charge transfer according to claim 1 is characterized in that, the length of described interconnection line test structure is greater than 110 microns, and width is between 6 microns to 8 microns.

7. the test structure of metal interconnecting charge transfer according to claim 1 is characterized in that, the test structure of described metal interconnecting charge transfer is on the metal level of semiconductor devices.

8. the test structure of metal interconnecting charge transfer according to claim 1 is characterized in that, described wire coil, interconnection line test structure and monitoring temperature resistance adopt identical materials.

9. utilize the method for testing of the metal interconnecting charge transfer of the described test structure realization of claim 1, it is characterized in that, comprise the steps:

(1) measures the temperature resistance coefficient of monitoring temperature resistance, measure the initial resistance of metal interconnecting wires test structure, monitoring temperature resistance, wire coil;

(2) electric current of change wire coil;

(3) change in resistance of monitor temperature monitored resistance by the temperature resistance coefficient of monitoring temperature resistance, changes into variation of temperature with the change in resistance of monitoring temperature resistance;

(4) judge whether to reach design temperature,, forward step (2) to if do not reach;

(5), then on the interconnection line test structure, add a steady current if reach design temperature;

(6) resistance variations of monitoring interconnection line test structure, and writing time;

(7) judge whether to reach failure criteria,, forward step (6) to if do not reach;

(8) if reach failure criteria, the output out-of-service time.

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