Novel test structure for speeding a stress-induced voiding test and method of using the same

Abstract

A test structure, comprising a first member having a first roughly rectangular shape, wherein the roughly rectangular shape of the first member has a first width dimension, and a first length dimension that is greater than the first width dimension; and a second member having a roughly rectangular shape, wherein the roughly rectangular shape of the second member has a second width dimension and a second length dimension that is greater than the second width dimension, wherein the second member is combined with the first member to form a roughly symmetrical cross-shaped test structure, and the test structure is used for testing stress-induced voiding.

1 . A test structure, comprising: 
 a first member having a first roughly rectangular shape, wherein the roughly rectangular shape of the first member has a first width dimension, and a first length dimension that is greater than the first width dimension; and    a second member having a roughly rectangular shape, wherein the roughly rectangular shape of the second member has a second width dimension and a second length dimension that is greater than the second width dimension, wherein the second member is combined with the first member to form a roughly symmetrical cross-shaped test structure, and the test structure is used for testing stress-induced voiding.    
     
     
         2 . The structure of  claim 1 , further comprising: 
 a first and second metal lines each having opposing ends;    the first and second metal lines being joined at two of their respective opposing ends to form an intersection; and    a via extending from the first and second metal line intersection to the approximate center of the cross-shaped test structure.    
     
     
         3 . The structure of  claim 1 , wherein: 
 the first length dimension of the first member is about twice as great as the first width dimension of the first member; and    the second length dimension of the second member is about twice as great as the second width dimension of the second member.    
     
     
         4 . The structure of  claim 1 , wherein the cross-shaped test structure is comprised of copper.  
     
     
         5 . The structure of  claim 1 , wherein the cross-shaped test structure has a thickness of from about 5000 to 10,000 Å.  
     
     
         6 . The structure of  claim 1 , wherein the cross-shaped test structure  100  has a thickness of about 5000 Å.  
     
     
         7 . The structure of  claim 1 , wherein the cross-shaped test structure is formed on a test wafer or a test site within a product wafer.  
     
     
         8 . The structure of  claim 1 , wherein the cross-shaped test structure is formed on a test wafer and the cross-shaped test structure occupies an area of from about 0.4 by 0.4 μm on the test wafer.  
     
     
         9 . The structure of  claim 1 , wherein the cross-shaped test structure is formed on a test wafer and the cross-shaped test structure occupies an area of from about 1.0 by 1.0 μm on the test wafer.  
     
     
         10 . A test structure, comprising: 
 a first member having a first roughly rectangular shape, wherein the roughly rectangular shape of the first member has a first side with a first width dimension W 1 , and a second side with a first length dimension L 1  that is greater than the first width dimension W 1 ; and    a second member having a roughly rectangular shape, wherein the roughly rectangular shape of the second member has a third side with second width dimension W 2  and a fourth side with a second length dimension L 2  that is greater than the second width dimension W 2 , wherein the second member is combined with the first member to form a roughly symmetrical cross-shaped test structure, wherein W 1  is larger than (L 2 -W 1 ) /2 or (L 1 -W 2 )/2, or W 2  is larger than (L 2 -W 1 )/2 or (L 1 -W 2 )/2.    
     
     
         11 . The structure of  claim 10 , wherein W 1  is larger than (L 2 -W 1 )/2.  
     
     
         12 . The structure of  claim 10 , wherein W 1  is larger than (L 1 -W 2 )/2.  
     
     
         13 . The structure of  claim 10 , wherein W 2  is larger than (L 2 -W 1 )/2.  
     
     
         14 . The structure of  claim 10 , wherein W 2  is larger than (L 1 -W 2 )/2.  
     
     
         15 . The structure of  claim 10 , further comprising: 
 a first and second metal lines each having opposing ends; the first and second metal lines being joined at two of their respective opposing ends to form an intersection; and    a via extending from the first and second metal line intersection to the approximate center of the cross-shaped test structure.    
     
     
         16 . A semiconductor device, comprising: 
 a substrate;    a test structure for testing voids in interconnects of the semiconductor device, disposed overlying the substrate and comprising:    a structure having a geometry with smaller area than that of a square test structure, wherein the test structure with the geometry has faster stress induced voiding failure than the square test structure.    
     
     
         17 . The structure of  claim 16 , wherein the test structure is substantially 75% area of the square test structure.  
     
     
         18 . The structure of  claim 16 , wherein the test structure is cross shaped.  
     
     
         19 . The structure of  claim 18 , further comprising: 
 a first and second metal lines each having opposing ends; the first and second metal lines being joined at two of their respective opposing ends to form an intersection; and a via extending from the first and second metal line intersection to the approximate center of the cross-shaped test structure.    
     
     
         20 . The structure of  claim 18 , wherein the cross-shaped test structure is comprised of copper.