Stress migration evaluation method
First Claim
1. A method for evaluating stress migration effects on a conductive runner fabricated according to a given fabrication process, said method comprising the steps of:
- heating said runner at a first temperature for a first time period to induce material interactions at an accelerated rate, said runner fabricated according to said given fabrication process;
cooling said runner to a second temperature, and maintaining said second temperature for a time of sufficient duration such that relaxation occurs;
heating said runner at a third temperature for a time sufficient to nucleate a predetermined number of voids;
heating said runner at a fourth temperature, less than said third temperature and greater than room temperature, to propagate said voids such that a maximum void size is determined.
9 Assignments
0 Petitions
Accused Products
Abstract
A method for accurately and objectively evaluating stress migration effects on long term reliability of integrated circuits. A sample containing a conductive runner is fabricated according to a given fabrication process. The fabricated sample undergoes a heating step at a first temperature for a first time period to induce material interactions at an accelerated rate, followed by cooling the sample to a second temperature and maintaining the second temperature for a time of sufficient duration such that relaxation occurs. Then the sample undergoes a heating process at a third temperature for a time sufficient to nucleate a predetermined number of voids, followed by heating the sample runner at a fourth temperature, less than than the third temperature, to propagate the voids such that a maximum void size is determined. Void distribution is preferably monitored by optical and scanning electron microscopy. By analyzing the void size distribution data for the isothermal void propagation annealing, a measure of the long term reliability is provided.
35 Citations
20 Claims
-
1. A method for evaluating stress migration effects on a conductive runner fabricated according to a given fabrication process, said method comprising the steps of:
-
heating said runner at a first temperature for a first time period to induce material interactions at an accelerated rate, said runner fabricated according to said given fabrication process; cooling said runner to a second temperature, and maintaining said second temperature for a time of sufficient duration such that relaxation occurs; heating said runner at a third temperature for a time sufficient to nucleate a predetermined number of voids; heating said runner at a fourth temperature, less than said third temperature and greater than room temperature, to propagate said voids such that a maximum void size is determined. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method for fabricating integrated circuits, comprising the steps of:
forming at least one conductive runner layer or at least one interlayer dielectric according to processing parameters predetermined based on executing a stress migration evaluation method on each of an array of conductive runner samples fabricated according to respective processing parameters, the stress migration evaluation method comprising the steps of; heating the conductive runner sample at a first temperature for a first time period to induce material interactions at an accelerated rate; cooling the conductive runner sample to a second temperature, and maintaining said second temperature for a time of sufficient duration such that relaxation occurs; heating the conductive runner sample at a third temperature for a time sufficient to nucleate a predetermined number of voids; heating the conductive runner sample at a fourth temperature, less than said third temperature and greater than room temperature, to propagate said voids such that a maximum void size is determined. - View Dependent Claims (14, 15, 16)
-
17. An integrated circuit comprising an interconnect conductive layer or an interlayer dielectric formed according to a process which is predetermined based on executing a stress migration evaluation method on each of an array of conductive runner samples fabricated according to respective processing parameters, the stress migration evaluation method comprising the steps of:
-
heating the conductive runner sample at a first temperature for a first time period to induce material interactions at an accelerated rate; cooling the conductive runner sample to a second temperature, and maintaining said second temperature for a time of sufficient duration such that relaxation occurs; heating the conductive runner sample at a third temperature for a time sufficient to nucleate a predetermined number of voids; heating the conductive runner sample at a fourth temperature, less than said third temperature and greater than room temperature, to propagate said voids such that a maximum void size is determined. - View Dependent Claims (18, 19, 20)
-
Specification